Inhibition Effect of Natural Pozzolan and Zinc Phosphate ...InternationalJournalofCorrosion Pre-cleaning of steel specimens in an alkaline solution (pH~12) Rinsing by water Pickling

Research ArticleInhibition Effect of Natural Pozzolan and Zinc Phosphate Bathson Reinforcing Steel Corrosion

Aref M al-Swaidani

Associate Professor Faculty of Architectural Engineering Arab International (Formerly European) University Damascus Syria

Correspondence should be addressed to Aref M al-Swaidani aydlswaidaniyahoofr

Received 26 January 2018 Accepted 24 May 2018 Published 2 July 2018

Academic Editor Tuan A Nguyen

Copyright copy 2018 Aref M al-SwaidaniThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Zinc phosphate (ZnP) baths are widely used for increasing corrosion resistance and surface preparation for painting Studies onexploiting these baths in the reinforced concrete (RC) are still in the early stages This is probably due to the shortcomings such asthe alkaline instability and high porosity of the obtained coatings Use of natural pozzolan (NP) as cement replacement is growingrapidly due to its economic ecological and technical benefits The combined effect of using ZnP baths and NP-based cementon the resistance of concrete against damage caused by corrosion has been investigated Four phosphating baths were preparedZnP ZnP-Ni ZnP-Cu and ZnP-Mn Steel specimens were phosphated at 55-60∘C for 15 min Concrete specimens were producedwith four different levels of NP 0 (control) 10 20 and 30 The investigation was carried out using RC specimens wherea constant anodic potential was impressed after 28 and 90 days of concrete curing The electrochemical behavior of the coatedsteel has further been evaluated in chloride contaminated Ca(OH)2 saturated solution (CH-Cl) using the open circuit potential(OCP) the potentiodynamic polarization and the polarization resistance with time The bond strength between the coated steeland concrete has been evaluated by the pull-out test Test results showed that concrete containing NP at higher replacement levelsand steel specimens treated in bication baths exhibited corrosion initiation times several times longer than the control concretewith uncoated steel In addition the best corrosion performance was noted in the steel specimen treated in the ZnP-Cu bath Itscorrosion density was about twentyfold lower with respect to the bare steel and its inhibition efficiency exceeded 95 in (CH-Cl)solution In addition its polarization resistance was about fifteenfold lower with respect to the bare steel SEM EDX and XRDtechniques have been employed as well

1 Introduction

Reinforcing steel embedded in fresh concrete develops aprotective passive layer on its surface This layer which isformed as a result of the high alkalinity of the concrete poresolution (pH sim 13) consists of 120574-Fe2O3 adhering tightly tothe steel As long as that oxide film is present the steelremains intact [1] However chloride ions attack and concretecarbonation can destroy the film and in the presence ofH2O and O2 reinforcement corrosion takes place Chlorideions which were described by Verbeck [2] as the specific andunique destroyer can be present in concrete through the useof either contaminated aggregate sea water brackish wateror admixtures containing chlorides [1]

In the literature there are state-of-the-art review studieson numerous methods of protection against reinforcement

corrosion [3ndash8] A variety of protective coatings such aszinc and epoxy coatings have widely been used to improvethe corrosion resistance of reinforcing bars Treatments ofreinforcing steel in zinc phosphate baths could probably bea vital approach in the future [9ndash12]

The phosphating process has been known for over acentury [13] It was extensively used in the automobileand appliance industries [14 15] This treatment primarilyprovides an inexpensive [15 16] nontoxic [17 18] reasonablyhard highly adherent and electronically nonconductingphosphate coating [13]

The insulation properties make an important contri-bution to the prevention of reinforcement corrosion [19]Further the zinc phosphate baths are currently consideredeco-friendly [20] However the obtained phosphate coatingsusually contain pores which are pathways for the corrosive

HindawiInternational Journal of CorrosionVolume 2018 Article ID 9078253 18 pageshttpsdoiorg10115520189078253

2 International Journal of Corrosion

electrolyte diffusion into the metal substrate As a result thecorrosion resistance of the conventional phosphate coating isnot high enough Additives such as Ni2+ Cu2+ Mn2+ Ca2+and Mo2+ and nanoparticles have been extensively used toproduce phosphate coatings with uniform structure lowerporosity higher corrosion resistance and improved adhesionproperties [11 15 21ndash25] A brief state-of-the-art review ofthese additives and their effects on the characteristics of zincphosphate baths has recently been published by the author[26]

Zinc phosphating is essentially an electrochemical pro-cess [27] When the steel comes into contact with phosphatesolution which is basically a phosphoric acid-based solutionan electrochemical reaction takes place Fe2+ ions start todissolve and release electrons at the anodic site and thereduction of H+ occurs at the cathodic site The evolutionof hydrogen and consumption of H+ ions result in a localincrease of pH at the surface leading to precipitation ofzinc phosphate crystals [28] According to Zimmermann etal [23] Donofrio [29] and Kunst et al [30] the possiblereactions taking place in the zinc phosphating bath are asfollows

3Zn2+ + 2H2PO4minus + 4H2O 997888rarr

Zn3 (PO4)2 4H2O (Hopeite) + 4H+

(1)

2Zn2+ + Fe2+ + 2H2PO4minus + 4H2O 997888rarr

Zn2Fe (PO4)2 4H2O (Phosphophyllite) + 4H+

(2)

The alkaline stability of the obtained zinc phosphatecoating on steel is of great importance as it will be embeddedin a highly alkaline environment (pHsim13) Literature showsthat the alkaline stability of zinc phosphate coatings dependson their chemical composition and crystal structure [31]Hopeite (Zn3(PO4)24H2O) has a higher alkaline solubilitythan phosphophyllite (Zn2Fe(PO4)2H2O) [29 32 33] Thusalkaline solutions first dissolve the coating composed ofhopeite Then the dissolution continues for layers rich iniron and those mainly composed of phosphophyllite [34] Ingeneral the presence of phosphophyllite is associated with abetter corrosion resistance than hopeite probably due to itsenhanced chemical stability relative to alkaline electrolytes[35]

Natural pozzolan (NP) is being widely used as cementreplacement due to its ecological economic and perform-ance-related advantageous properties [36ndash41] However itsuse caused a lower alkalinity compared with plain Portlandcement [42] This could be due to the reduction in cementcontent (ie the dilution effect) when adding natural poz-zolan and the consumption of portlandite (CH) through thepozzolanic reaction

Syria is rich in natural pozzolan with estimated reservesof about one billion tonnes [43] There are a significantnumber of studies that deal separately with the effect of usingnatural pozzolan or that of zinc phosphating process on thecorrosion of reinforcing steel However very little or evenno previous works as the author thinks have been carriedout in the past to investigate the combined effect of adding

NP as cement replacement and zinc phosphate coated steelon the anticorrosion properties of reinforcing steel exposedto highly chloride ion concentrations In addition literaturedid not cover the benefit in terms of alkaline stabilitywhich can be achieved when the zinc phosphate coatedsteel is embedded in concrete of relatively lower alkalinityFurther the reduced concrete permeability offered by NP-based cements could be considered an additional physicalbarrier between steel and its environment

The objective of this paper is to investigate the influenceof adding NP as cement replacement on the corrosionperformance of reinforcing steel treated in different zincphosphate baths Four binders with different replacementlevels of NP (0 10 20 and 30) have been producedfor this investigation In addition four zinc phosphatingbaths were employed the first one is a monocation bath (ieit contains only Zn-cation) and three bication baths Zn-Ni Zn-Cu and Zn-Mn respectively Two test environmentswere created for this investigation concrete specimens anda contaminated Ca(OH)2 saturated solution in which thecoated steel was embedded or immersed

The study is of particular importance for the followingpoints

(i) Replacement of OPC by natural pozzolan could sig-nificantly minimize CO2 released into atmosphereand save energy In addition zinc phosphating pro-cess is considered eco-friendly

(ii) This study is the first of its kind in Syria However itis not limited to the country It can be applied to othercountries of similar geology eg Harrat Al-Shamah avolcanic field which covers a total area of some 45000km2 and about 15000 km2 is located in the countryThe rest covers parts of Jordan and KSA

(iii) As our country begins preparations for the hugereconstruction after the war comes to its end theencouraging results can be considered a motivationof other studies for instance use of these localsupplementary cementing materials in enhancementof the anticorrosion properties of reinforced concretemade from recycled concrete aggregates (RCA) RCAare expected to be an inevitable building materialduring the postwar reconstruction in Syria

2 Experimental Procedure

21 NP-Based Concrete Natural pozzolan (NP) used in theexperiments was collected from a Tal Shihan quarry 70 kmsoutheast of Damascus More detailed information related toits characteristics can be found in the latest research work ofthe author and colleagues [44]

Four binder specimens have been prepared one plainPortland cement CEM I (control) and three binary binderswith three replacement levels of 10 20 and 30 NP (EN197-1) 5 of gypsum was added to all the binder specimensThis ratio is frequently used by all Syrian cement plantsproviding about 235 SO3 content The amount of gypsumadded to the cement clinker is expressed usually as the

International Journal of Corrosion 3

Pre-cleaning of steel specimensin an alkaline solution (pH~12)

Rinsing by water

Pickling in 10 HCl solution

Rinsing by distilled water

Drying using an electric dryer

Rinsing by deionized water

Final drying

pH~2 for 15 minPhosphating at 55-60 and∘C

Figure 1 A schematic representation of the full steps of phosphating process

mass of SO3 present this is limited by European StandardBS EN 197-1 2000 to a maximum of 35 percent [45] Allreplacements were made by mass of cement All binders weredesignated according to the replacement level For instanceNP10 and NP30 refer to the binders containing 10 and 30of NP respectively More data on the characteristics of thebinder components namely particle size distribution and thegrinding method can also be found in the scientific work ofthe author and colleagues [44]

Four concrete mixes have been prepared using the sameconstituents and procedure followed by the author in hislatest work [44] Concrete cubes (150 mm) were cast for thedetermination of compressive strength and water permeabil-ity Concrete cylinders of 75 mm times 150 mm and 100 mm times200 mm were also cast for testing the concrete porosity andthe concrete chloride ion penetrability respectively The RCspecimen for the accelerated corrosion test was 100 mm times200mm concrete cylinder in which 14 mm diameter steel barwas centrally embeddedThe steel bar was embedded into theconcrete cylinder such that its end was at least 45 mm fromthe bottomof the cylinder and it was coatedwith epoxy at theexit from the concrete cylinder in order to eliminate crevicecorrosion

22 Zinc Phosphate Baths Four zinc phosphate baths werecreated conventional bath ormonocation bath withoutmod-ifying elements and three bication baths modified either bynickel (Ni2+) copper (Cu2+) or manganese (Mn2+) cationsTheir chemical compositions and designations are illustratedin Table 1 All the chemical reagents applied in the presentwork were of analytic grade Deionized water was used in allzinc phosphating baths Phosphating process was carried out

by the conventional immersion of reinforcing steel specimensat 55-60∘C for 15 min in the phosphating baths at a pHvalue of 2plusmn01 The phosphating process primarily includedprecleaning activation phosphating rinsing and dryingThe full steps of the phosphating process are schematicallyillustrated in Figure 1The chemical composition of steel rebarwith some mechanical properties is presented in Table 2A macrograph of treated steel specimens with an opticalmicroscopic photo is shown in Figure 2 A ZnP-Ni coatingof about 8 120583m thickness can clearly be seen in Figure 2(b)

23Morphology of Zinc PhosphateCoatings Themorphologyand elemental composition of the obtained zinc phosphatecoatings were studied by scanning electron microscope(SEM VEGA II TESCAN) and energy disperse X-ray (EDX)spectrometer

24 Mechanical and Durability-Related Tests of Concrete

241 Compressive Strength Water Permeability Chloride IonPenetrability and Porosity Tests The compressive strengthdevelopment of concrete was conducted on 150 mm cubicconcrete specimens in accordance with ISO 4012 at agesof 28 and 90 days Concrete permeability measured interms of depth of water penetration has been carried outas per the standard EN 12390-8 The results shown in thispaper are the average penetration depth The rapid chloridepenetrability (RCP) test was conducted in accordance withASTM C1202 Three cylinder specimens of each concretemix were tested after 28 and 90 days of curing Porositymeasurements were conducted using vacuum saturationmethod in accordance with RILEM CPC 113 The results


(a) (b)

Figure 2 (a) Photograph of the some phosphated steel rebars (b) an optical microscopy photo of cross-sectional ZnP-Ni treated steel

Table 1 Chemical composition of the prepared zinc phosphating baths

Bath type Designation Concentration (Molel)PO43- NO3

1- Zn2+ Ni2+ Cu2+ Mn2+

Mono-cation bath (conventional) ZnP 034 014 017 0 0 0

Bi-cation bathsZnP-Ni 034 014 017 0017ZnP-Cu 034 014 017 0017ZnP-Mn 034 014 017 0017

Table 2 Chemical composition with some physical characteristics of the steel bars used in the experiments

Rebar type Chemical composition () Mechanical propertiesC Si Mn P S Ni Cu Elastic point (MPa) Tensile strength (MPa) Elongation ()

14 mm (RB 400) 023 011 054 0006 0009 0001 0001 4887 6382 15

reported represent the average of six readings for compressivestrength test and the average of three readings for all othertests

242 Accelerated Corrosion Test A rapid corrosion test wasused to compare the corrosion performance of NP-basedcement concrete in which either straight phosphate rebars orbent phosphate rebars are embedded as shown in Figure 3The objective of evaluating the bent phosphated rebars is toverify the coating soundness and to investigatewhether or notthe bending action might affect its corrosion performanceSimilar techniques with little differences were reported byother researchers [36 46ndash50]The cylindrical specimen shapewas adopted to provide uniform cover and easier fabricationIn the study RC specimens were immersed in a 15 NaClsolution leveling half of the concrete cylinder and the steel bar(working electrode) was connected to the positive terminalof a DC power source while the negative terminal wasconnected to a steel plate (counter electrode) placed near theconcrete specimen in the solutionThe corrosion process wasinitiated by impressing a relatively high anodic potential of 12V to accelerate the corrosion processThe instrument used inthe test is a LaboratoryDCpower supplyModel GPC-60-300equipped with a Digital Multimeter Sanwa CD 721

Figure 3 shows a schematic representation of the experi-mental setup for the accelerated corrosion testThe specimenswere monitored periodically to see how long it takes forcorrosion cracks to appear on the specimen surface Thecurrent readings with time were recorded at 3 h intervalsThree specimens from each concrete mix and phosphatingbath were tested after 28 and 90 days of curing

243 Bond Strength Test Pull-out tests and beam tests arethe common experimental methods used for assessmentof bond performance [51] In the study the concrete cubespecimens were tested to determine the bond strengthbetween steel rebars and concrete using the concentric pull-out test This concentric pull-out test was similar to thatoutlined in ASTM C 234 Although this type of test doesnot represent the actual situation in a structure the authorsused this method since the study is basically a comparativestudy The pull-out test was carried out using 150 mm cubicspecimens with the bar centrally embedded Deformed steelbars with 16 mm in diameter were used instead of no 6(19 mm) bars specified in ASTM C 234 which is used asthe basis of casting and testing procedures Each mold wasdesigned to cast one 150 mm cubic specimen as shownin Figure 4(a) The mold was made of steel plates The


~50

mm

~50

mm

~50 mm ~50 mm

~50 mm~50 mm

(a) (b)

Epoxy coating

Power Supply (~)

45 mm

Rectifier (12 V) Ammeter

+ -

Steel plate (Cathode)

Lollipop specimen

Steel bar (Oslash14 mm)(Anode)

15 NaCl solution

200mm

100 mm

100 mm

(c)

Figure 3 ((a) and (b)) Schematic representation of the concrete specimen with bent steel rebar (c) Schematic representation of experimentalsetup for the accelerated corrosion test

holed cap was designed to support the bar in a verticalposition

The embedment length of reinforcing bars was 72 mm(sim45 times the rebar diameter) The required embedmentlength has been obtained by breaking the bond between steeland concrete using polyvinyl chloride (PVC) sleeves to coverthe unembedded length The gap between the reinforcingsteel and sleeves was sealed with a silicon sealant

Sketch map of the bond test setup and a photograph ofthe bond test frame with the specimen in position are shownin Figures 4(b) and 4(c) The specimen was mounted in theframe with the bar passing through the slot in the frame Adigital dial indicator has been installed on the free end tomeasure the rebarrsquos displacements

A 2000 kN capacity universal testing machine has beenused for the pull-out testing The bond stress (120591) has been

calculated by dividing the applied load (119865) by the surface area(120587Oslash119897) of reinforcing steel in contact with concrete as shownin the following formula

120591 =119865

120587Oslash119897(3)

where 119897 is the length of embedment (72 mm) and Oslash is thediameter of the reinforcing bar (16 mm)

The free-end slip values were plotted against the bondstresses and the bond strengths at failure have been deter-mined for each concrete mixture and curing age

25 Tests in Chloride Contaminated Ca(OH)2 Saturated Solu-tion A saturated Ca(OH)2 solution with an approximate pHof 125 was used to simulate the pore solution existing inconcrete 35 NaCl was added to the saturated Ca(OH)2


(a)

Bond test frameConcrete cube

Reinforcing steel

Digital dial indicator

Unloaded end

Slippage direction

Machine grips

Bond breaker

(b) (c)

Figure 4 (a) Photograph of the mold used in the bond test with the bar in place (b) sketch map of the bond set up (c) photograph of thebond test setup with the specimen in position

solution to simulate reinforced concrete exposed to chlo-ride attack The obtained chloride contaminated solution isdenoted (CH-Cl) Its pH value was about 123 In numerousstudies of reinforcement corrosion saturated Ca(OH)2 hasbeen used as a substitute for concrete pore solution [52]

The electrochemical tests in the (CH-Cl) solution wereperformed with a three-electrode system The working elec-trode was either the coated steel or the bare steel the counterelectrode was a platinum sheet and the reference electrodewas a saturated Calomel electrode (SCE) The surface areaof the working electrode exposed to the solution was 6cm2 Different electrochemical methods were employed toevaluate the corrosion behavior of the coated steel specimensFirst the coated and bare steel specimens were immersedin the test solution for one hour to reach stationary opencircuit potential (OCP) Second polarization curves havebeen measured with a scan rate of 05 mVs and a scan rangefrom -025 V for OCP to + 025 V for pitting potentialThird periodic measurements of linear polarization resis-tance (LPR) over time were performed during 96 h Thespecimens were polarized at plusmn20mVwith respect to the opencircuit potential (Eocp) at a scan rate of 05 mVs and theLRP measurements were taken every 30 minutes For a smallperturbation about the open circuit potential there is a linearrelationship between the change in applied current per unitarea of electrode (Δi) and the change of the measured voltage(ΔE) The ratio (ΔEΔi) is called polarization resistance (Rp)The testing temperature was 25∘C

After the test the specimens were rinsed at room temper-ature and the surface was observed and analysed with SEMand EDX SATOE STADI X-ray diffractometer (XRD) usingCuK120572 radiation operated at 40 KV and 30 mA with a scanmode ranging from 5 to 85∘ and a scan speed of 2∘min was

also employed in order to investigate the phases formed onthe coated steel surface after immersion in (CH-Cl) solution

All the electrochemical tests were performed using apotentiostat (TACUSSEL PGZ 301) at ambient temperatureThe tests were repeated three times with the same conditionsfor confirming the reproducibility of the obtained zincphosphate coatings All electrochemical experiments wereremarkably reproducible

3 Results and Discussion

31 Morphology and Chemical Composition of Zinc Phos-phate Coating Scanning electron micrographs of the zincphosphate coatings obtained during the phosphating processare shown in Figures 5ndash8 The SEM observations give moredetail about the modifications of coating morphology withthe cation type in the phosphating solutions

For the monocation bath ZnP bath the coating seems tobe porous It consists of platelet shaped crystallites of 30ndash40120583m length and 5ndash10 120583m width which uniformly covered thesurface of the specimen Figure 5 However the presence ofNi2+ Cu2+ and Mn2+ cations in the phosphating solutionsresulted in a significant modification of the crystalline formand size

The ZnP-Ni coating is smoother than the monocationZnP coating Its structure is characterized by platelets withsizes up to 20 120583m in length and up to 3 120583m in width asshown in Figure 6 The grain refinement was also reportedin literature [9 35 53 54] The relatively high weight of Ni inthe coating as confirmed by the EDX analysis may indicatethe substitution of Zn2+ by Ni2+ in hopeite or the depositionof Ni in the coating This result was in agreement with theresults obtained by Zimmermann et al [23] and Su and Lin


0 13 26 39 52 65 78 91 104

Fe LP L

Zn k

Zn k

Fe k

Fe k

P k

Zn L

C k

O k

Si k

117k

104k

91k

78k

52k

26k

0

65k

39k

13k

Figure 5 SEM and EDX of ZnP coating

0 13 26 39 52 65 78 91 104

Fe K Zn K

Fe K Fe K

P K

Si K

C K

Fe LNi K

O K

Ni K

Zn L

P L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k

Figure 6 SEM and EDX of ZnP-Ni coating

0 13 26 39 52 65 78 91 104

Fe LC K

Fe K

p K

Zn L

Cu L

P L

S K

156k

13k

104k

78k

52k

26k

0

Figure 7 SEM and EDX of ZnP-Cu coating


0 13 26 39 52 65 78 91 104

Fe K Zn K

Zn KFe KMn KMn K

P K

Si K

Zn LO K

C KP L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k

Figure 8 SEM and EDX of ZnP-Mn coating

[55] who proposed the formation of Zn(3-x)Nix(PO4)2yH2OAccording to Kulinich and Akhtar [56] Ni2+ has two mainroles in the zinc phosphate coating mechanism First therate of increase in local solution pH is limited by theslower kinetics of reactions involvingNi2+ compared to Zn2+leading to thinner zinc phosphate coatings when Ni2+ ispresent in the coating solution Second most Ni2+ depositionoccurs during the later stages of the coating process by nickelphosphate deposition and formation of Ni-rich corrosion-resistant oxide

TheZnP-Cu coating consists of smaller grains the dimen-sions of which varied between 2 and 6 120583m Copper as clearlyseen in Figure 7 modified and refined the crystal structureand enhanced the coverage of the surface significantly Thiswhich was in agreement with the results obtained by Abdallaet al [57] can be attributed to the effect of CU-Fe galvaniccouple on dissolution of iron and acceleration of crystaldeposition [57] From the EDX analysis Figure 7 it canclearly be distinguished that the dominant element wascopper Therefore the metal surface exposed between theformed crystals might be a surface of copper rather than thebase metal This result is in well agreement with the result ofOgle andBuchheit [35] who concluded that Cu2+may depositas copper metal on the surface

From Figure 8 it is noted that the ZnP-Mn coating iswell crystallized and it completely covers the steel surfaceIts structure is characterized by small platelets whose widthis about 3 120583m and length is 15 120583m Manganese (Mn2+)behavior to some extent in the phosphating bath is similarto that of Ni2+ as clearly seen in Figure 8 In addition Mn2+may replace Zn2+ in the hopeite crystal lattice The presenceof Mn2+ in the coating may support this assumption asclearly seen from the EDX analysis in Figure 8 This was inagreement with the results obtained by Su and Lin [55] whoproposed the formation ofMn2Zn(PO4)24H2O Rezaee et al[21] also observed this formation In addition adding Mn2+reduced the phosphate coating porosity and improved surfacecoverage which led to an enhanced corrosion resistance[21]

0102030405060708090

Curr

ent (

mA

)

50 100 150 200 2500Time (Hour)

NP0NP10

NP20NP30

Figure 9 Typical curves of corrosion current versus time ofconcrete specimens tested after 28 days of curing

32 Compressive Strength and Permeability-Related Proper-ties of Concrete Tables 3 and 4 show the test results ofcompressive strength water penetration depth chloride ionpenetrability and porosity of concrete The test results willnot be discussed here as the same trend of results using thesame or a similar natural pozzolan was studied in depth inrecent works carried out by the author [44 58] In additionthe microstructural investigation of the hydration productscan also be found in these works

33 Corrosion Resistance of Coated Steel Specimens Embeddedin NP-Based Concrete Typical curves of corrosion currentversus time for the reinforced concrete specimens made withNP-based binders and phosphate steel rebars are illustrated inFigures 9ndash12 respectively As shown in Figures 9ndash12 current-time curve initially descended till a time value after whicha steady low rate of increase in current was observed andafter a specific time period a rapid increase in current wasdetected until failure The decreasing tendency of currentat the very early time could be explained by the filling ofthe pores with salt and other deposits in the salt water[36]


Table 3 Compressive strength development of concrete

Mix type Compressive (119891c) strength of concrete (MPa) normalized28 days of curing 90 days of curing

NP0 421-100 479-100NP10 401-95 469-98NP20 342-81 437-91NP30 323-77 478-89

Table 4 Water penetration depths porosity chloride penetrability and pH of the investigated concrete

Curing time Binder type Water penetration depth (mm) Porosity () Chloride penetrability (Coulombs) pH

28 days

NP0 65 172 6278 1265NP10 61 157 5891 1234NP20 48 142 4367 1208NP30 42 111 2915 1201

90 days

NP0 53 144 3971 1257NP10 43 122 3214 1219NP20 29 97 1965 1191NP30 22 68 1112 1193

Bare steel-NP1028 days of curingZnP-NP1028 days of curingZnP-Mn-NP1028 days of curingZnP-Ni-NP1028 days of curingZnP-Cu-NP1028 days of curing

0

10

20

30

40

50

60

70

80

90

Curr

ent (

mA

)

20 40 60 80 100 120 140 160 1800Time (Hour)

Figure 10 Time to cracking of RC specimens made with NP10-based cement and phosphated steel rebars after 28 days of curing

Almost a similar variation of the corrosion current withtime has also been observed by other researchers [46 50]Thefirst visual evidence of corrosionwas the appearance of brownstains on the surface of the specimens Crackingwas observedshortly thereafter and it was associated with a sudden rise inthe current

Figure 13 presents the average corrosion times requiredto crack the specimens made with NP-based binders andphosphated steel rebars Time to cracking in NP0-basedconcrete specimens was in the range of 87ndash134 h (36ndash56days) whereas that in NP30-based concrete was in the range


50 100 150 200 2500Time (Hour)

0

10

20

30

40

50

60

70

Curr

ent (

mA

)


of 197ndash367 h (82ndash153 days) In addition it was observed inFigure 13 that the corrosion resistance of NP-based cementconcrete specimens increased significantly with age whilethat of the plain cement concrete had a slight increase whichhas also been indicated by other researchers [36 50]

The combined effect of using NP-based cement concreteand zinc phosphated steel rebars can clearly be seen inFigure 13 From the graphs it is very clear to note that the timetaken for initiation of 28-day cured concrete cracking wasfound to be 197 215 246 263 and 232 h for bare steel rebarZnP coated steel rebar ZnP-Mn coated steel rebar ZnP-Nicoated steel rebar and ZnP-Cu coated steel rebar which wereembedded in NP30-based concrete respectively The best


bare steel-NP30ZnP-NP30ZnP-Ni-NP30

ZnP-Cu-NP30ZnP-Mn-NP30

0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)


Bare steel ZnP ZnP-Ni ZnP-Cu ZnP-MnBath type

NP30-28 days of curingNP30-90 days of curingNP20-28 days of curingNP20-90 days of curing


0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

Figure 13 Average corrosion times of RC specimens at 28 and 90days of curing (straight rebars)

corrosion resistance was noted in the following system ZnP-Cu bath-NP30-based cementTheZnP-Cu coated steel rebarsembedded in NP30-based concrete have taken about 4 timeslonger duration for crack initiation than the bare steel rebarsembedded in NP0-based concrete The test lasted for 261 and523 h in this specimen after 28 and 90 days of curing timesrespectively

This delay in corrosion time can be attributed to thefollowing (i)Thepozzolanic reaction between glassy phase inNP and CH released during cement hydration contributes tofilling the voids and pores in concrete with an additional C-S-HThis leads to decrease of pore size and to a smaller effectivediffusivity for chloride [36]This whichwas confirmed by thewater penetration depth chloride penetrability and concreteporosity tests can also improve the long-term corrosionresistance of RC structures andmake concrete denser and lesspermeable [36 50] (ii) The role of Cu2+ cation in refinement

of the coating was confirmed by SEM and EDX analysisFigure 7 (iii) The deposition of Cu2+-based layer on thephosphated steel rebars contributes to forming a physicalbarrier between the base metal (steel) and its environment(iv) Bication baths enhance the alkaline stability of the zincphosphate coatings According to Simescu and Idrissi [11]study the dissolution of ZnP-Ni coating in the alkalinemedium (pH sim125) is accompanied by the formation ofhydroxyapatite Ca10(PO4)6(OH)2 Hydroxyapatite formationoccurs even in the presence of aggressive chloride ions [11]This chemical compound provides an effective protectionagainst reinforcement corrosion and contributes to the reduc-tion in chloride aggressiveness [10] (v) Adding NP as cementreplacement reduced pH values of concrete as seen in Table 4This reduction can be due to the consumption of CH throughthe pozzolanic reaction and the lower cement content (iethe dilution effect)

From this accelerated test it is also confirmed that thebication phosphating baths have higher corrosion resistancewhen compared to the monocation bath at all replacementlevels of NP

Further it is worth mentioning that the bending actiondid not negatively affect the corrosion resistance of thephosphated steel rebars The maximum reduction which wasnoted in ZnP treated rebar did not exceed 6

34 Bond Strengths The bond stresses at 025 mm slip andat failure were presented in Table 5 It can be clearly seenthat phosphate coatings applied to the embedded steel did notsignificantly reduce the bond strength of steel with concreteAfter 28 days of curing some of the phosphating bathsincreased the bond strength (ie ZnP-Cu ZnP-Ni) whilethe other slightly decreased the bond strength with concrete(ie ZnP-Mn and ZnP) However after 90 days of curingall phosphated steel rebars achieved higher bond strengthswhen compared with the bare steel embedded in the controlconcrete

35 Corrosion Behavior of Coated and Bare Steel in (CH-Cl) Solution The open circuit potential values which wererecorded after stabilization for the coated and bare steelspecimens are illustrated in Figure 14 The results show thatthe potentials are becoming more noble for bication zincphosphate coatings and theZnP-Cu coating is themost nobleone However an inversion appears for the monocation zincphosphate coating (ie ZnP bath) This according to theauthor can be explained by the following

(i)Thepresence of Cu orNi in the bication zinc phosphatecoatings may increase the potential values as copper andnickel are more noble than steel

(ii) The formation of passive phases may make thepotential more noble over time This was confirmed by SEMEDX and XRD analysis as shown in Figures 17ndash20

(iii) The additives contribute to refinement of zinc phos-phate crystals [26]

The polarization curves are shown in Figure 15 Uponincreasing the potential above Ecorr which corresponds tothe minimum current density a passive region was observedwhere the current density was of the order of 120583Acm2 Pitting


Table 5 Bond stresses (MPa) of the investigated phosphate steel rebars

Concrete type Rebar typeBond stresses (MPa)

28 days of curing 90 days of curingat 025 mm slip at failure at 025 mm slip at failure

NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547

ZnP-Ni 845 1434 887 1608ZnP-Cu 828 1441 891 1588ZnP-Mn 814 1403 878 1527

NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE

minus650 minus600 minus550 minus500

ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu

minus350minus400minus450

Figure 14 OCP values of the obtained coatings after stabilization

Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)

06040200 08 10minus04minus06minus08 minus02minus10E (VSCE)

Figure 15 Polarization curves for zinc phosphate coating and baresteel after immersion in (CH-Cl) solution

occurred in the bare steel at a potential value of less thanzero On the other hand at potential values higher than06 VSCE an increase in the current density was observedin ZnP-Cu and ZnP-Ni specimens This sharp increase inthe current density corresponds to the pitting potential EpitDue to the effective barrier offered by the bication zincphosphate coatings the average polarization current declinesconsiderably as compared to the bare steel Table 6 presentsEcorr Icorr Epit and passivity range of specimens after thepolarization test Among all the investigated coatings theZnP-Cu and ZnP-Ni coated specimens exhibited the lowestvalues of Icorr about twentyfold lower with respect to the baresteel In addition these coatings revealed a passive region ofabout 1000mVThe inhibition efficiency (IE) has further beenestimated using the following equation [59]

119868119864 =[(Icorr)0 minus Icorr][(Icorr)0]

(4)

Here (Icorr)0 and Icorr denote corrosion current densityof reinforcing steel in the absence and presence of zinc


Table 6 Icorr Ecorr Epit the passivity range and the inhibition efficiency for the coated steel specimens and the bare steel

Zinc phosphate bath I (120583Acm2) Ecorr (VSCE) Epit (VSCE) Passivity range (VSCE) Inhibition efficiency ()Bare steel (Reference) 103 -0626 -0081 0545 -ZnP 24 -0646 0134 078 767ZnP-Mn 16 -0586 0243 0829 845ZnP-Ni 07 -0521 0468 0989 932ZnP-Cu 05 -0416 0594 101 951

Bare steelZnP-CuZnP-Ni

ZnP-MnZnP

10 20 30 40 50 60 70 80 90 1000Immersion time (Hour)

0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)

Figure 16 Polarization resistance over time of coated steel specimens and bare steel after 96 h of immersion in (CH-Cl) solution

phosphate coating respectively As illustrated in Table 6inhibition efficiency values of more than 90 were observedin the zinc phosphate coatings modified by either Cu2+ orNi2+ cations This result suggests that ZnP-Cu and ZnP-Nicoatings provide an effective corrosion resistance

The periodic measurements of linear polarization resis-tance are displayed in Figure 16 For the bication zinc phos-phate coatings the differences in the behavior are not verysignificant The polarization resistance decreases slightly atthe beginning of the immersionmeaning that the dissolutionrate of the bication coating slows down then the polarizationresistance increases probably due to the formation of apassive phase by the resulting products This result wasconfirmed by SEM EDX and XRD analysis as shown inFigures 17ndash20The formation ofmore than one passive phaseeven in the presence of chloride ions can clearly be seen inFigure 19 These passive phases led to a better protection ofsteel as evidenced by the polarization tests I = f(E) and Rp =f(t) After 96 h of immersion in the (CH-Cl) solution ZnP-Cu and ZnP-Ni coatings recorded polarization resistance ofabout 40 kOhmcm2 On the other hand the polarizationresistance of the bare steel and the monocation coatingrecorded values of less than 10 kOhmcm2

Based on the XRD analysis the presence of calciumhydroxyzincate Ca(Zn(OH)3)22H2O is clearly seen in allzinc phosphate coatings after 96 h of immersion in the (CH-Cl) solutionThis compound is themain corrosion product ofgalvanised steel in chloride contaminated concrete [60 61]

New peaks related to the formation of other products suchas hydroxyapatite Ca10(PO4)6(OH)2 and copper oxide weredetected in ZnP-Cu coating The formation of such passiveproducts in a highly alkaline solution contaminated withchloride ions was reported by other researchers [9ndash11 62]These products contribute to the decrease of the chlorideaggressiveness and provide an effective protection againstthe reinforcement corrosion although further investigationis needed to study their electrochemical behavior in a widerrange of pH and at different chloride ion concentrations Itis worth mentioning that the copper particles deposited inthe zinc phosphating remained intact as evidenced by thestrong peaks of copper shown in either EDX analysis or XRDdiffraction test Compared with that of bication baths themonocation bath has the worst corrosion performance whereuncovered steel zones can easily be distinguished in Figure 17These zones are attributed to the rapid dissolution of thephosphating coating and the complete breakdown of the localpassive layer

4 Conclusions

This paper was an attempt to investigate the effects of someadditives such as alkali metal ions on zinc phosphate bathproperties In addition the effect of using NP-based binderson corrosion performance was mainly studied

(i) Bication baths led to improvements in the zincphosphate coating performance in terms of reinforcement


Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K

P KCl L Ca K Cr K Zn K

Fe K

Cl KZn L

Fe L

Area 1 (Uncovered zone)

0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)

Zn Zinc휶Fe SubstratePhosphophyllite

HopeiteCalcium Hydroxyzincate

Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)

Figure 17 SEMs and EDX (a) and XRD analysis (b) of ZnP coating after immersion in (CH-Cl) solution for 96 h

corrosion resistance and bond strength between concreteand steel The best corrosion resistance was observed inthe ZnP-Cu-NP30-based binder system It took corrosioninitiation periods 4 times longer than the bare steel-NP0-based cement system The reduced chloride penetrabilitywater permeability and porosity of NP-based concrete spec-imens made a further significant improvement in termsof reinforcement corrosion resistance A similar excellent

corrosion performance was also noted in the ZnP-Ni systemas it performed very well in the electrochemical tests carriedout using either (CH-Cl) solution or concrete specimensAlthough ZnP-Mn coating performed to some extent wellbut its corrosion performance was not as high as the ZnP-Cuand ZnP-Ni coatings

(ii) Bent phosphated steel rebars did not significantlyaffect the corrosion performance


Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)

Figure 18 SEMs and EDX (a) and XRD analysis (b) of ZnP-Ni coating after immersion in (CH-Cl) solution for 96 h

(iii) Based on the results of bond strength it shouldbe noted that the hydrogen embrittlement which can beencountered in acidic baths may be considered negligible inthe studied phosphating baths

(iv) The stability of the phosphate layer in a highlyalkaline solution was significantly increased by modi-fying the zinc phosphating bath with Cu2+ Ni2+ andMn2+


Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper

Copper OxideHydroxyapatite

ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000

Zn Zinc휶Fe Substrate

PhosphophylliteHopeiteCalcium Hydroxyzincate

Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)

Figure 19 SEMs and EDX (a) and XRD analysis (b) of ZnP-Cu coating after immersion in (CH-Cl) solution for 96 h


Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K

Fe KMn K Zn KCa KMn K

Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)

Figure 20 SEMs and EDX (a) and XRD analysis (b) of ZnP-Mn coating after immersion in (CH-Cl) solution for 96 h

(v) Electrochemical test results revealed that the bicationcoatings performed very well in highly alkaline solutionscontaminated with chloride ions The inhibition efficiencyvalues ranged from about 85 to 95 The SEM EDX andXRD analysis supported this result where passive resultingproducts were detected

(vi) The microscopical examination of the monocationbath specimens after the polarization resistance test revealed

uncovered steel zones indicating that corrosion performanceof this bath may not be relied upon

(vii) Further studies on the chemical stability of themodified zinc phosphate coatings are highly recommendedLong-term tests when these coatings are exposed to chlorideions are also recommended Testing the efficiency of theformed phosphate coatings when immersed in concreteexposed to carbonation is recommended as well


(viii) Finally there is a need to develop an optimumchemical composition of the phosphating bath and treatmentconditions that provide maximum protection against rein-forcement corrosion

Data AvailabilityThe data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

The author declares that there are no conflicts of interestregarding the publication of this paper

References

[1] A Neville ldquoChloride attack of reinforced concrete an over-viewrdquoMaterials and Structures vol 28 no 2 pp 63ndash70 1995

[2] G J Verbeck ldquoMechanisms of Corrosion of Steel in Concreterdquoin Corrosion of Metals in Concrete vol SP-49 pp 21ndash38American Concrete Institute 1975

[3] A Poursaee ldquoCorrosion protection methods of steel in con-creterdquo Corrosion of Steel in Concrete Structures pp 241ndash2482016

[4] L Bertolini B Elsener P Pedeferri E Redaelli and R PolderCorrosion of Steel in Concrete Prevention Diagnosis Repair vol12 69469 Wiley-VCH Verlag GmbH Co Boschstr WeinheimGermany 2nd edition 2003

[5] B Elsener Corrosion Inhibitors for steel in concrete-state of theart report vol 35 EFC publication IOM CommunicationsLondon 2001

[6] J Carmona P Garces and M A Climent ldquoEfficiency of aconductive cement-based anodic system for the application ofcathodic protection cathodic prevention and electrochemicalchloride extraction to control corrosion in reinforced concretestructuresrdquo Corrosion Science vol 96 pp 102ndash111 2015

[7] C M Hansson ldquoCorrosion of stainless steel in concreterdquo inCorrosion of Steel in Concrete Structures A Poursaee EdElsevier Ltd 2016

[8] M Ormellese F Bolzoni S Goidanich M P Pedeferri and ABrenna ldquoCorrosion inhibitors in reinforced concrete structuresPart 3 - Migration of inhibitors into concreterdquo CorrosionEngineering Science and Technology vol 46 no 4 pp 334ndash3392011

[9] A A Elshami S Bonnet A Khelidj and L Sail ldquoNovelanticorrosive zinc phosphate coating for corrosion preventionof reinforced concreterdquo European Journal of Environmental andCivil Engineering vol 21 no 5 pp 572ndash593 2017

[10] F Simescu and H Idrissi ldquoEffect of zinc phosphate chemicalconversion coating on corrosion behaviour of mild steel inalkaline medium protection of rebars in reinforced concreterdquoScience and Technology of Advanced Materials vol 9 no 4 p045009 2008

[11] F Simescu and H Idrissi ldquoCorrosion behaviour in alkalinemedium of zinc phosphate coated steel obtained by cathodicelectrochemical treatmentrdquo Corrosion Science vol 51 no 4 pp833ndash840 2009

[12] OGirciene R Ramanauskas LGudaviciute andAMartuieneldquoFormation of conversion ZnNiMn phosphate coatings onsteel and corrosion behaviour of phosphated specimens in a

chloride-contaminated alkaline solutionrdquo Chemiji vol 24 pp182ndash189 2013

[13] P Zarras and J D Stenger-Smith ldquoSmart Inorganic andOrganic Pretreatment Coatings for the Inhibition of Corrosionon MetalsAlloysrdquo in Intelligent Coatings for Corrosion ControlA Tiwari and etal Eds Butterworth-Heinemann 2015

[14] D G Weldon Failure Analysis of Paints and Coatings JohnWiley amp Sons Ltd 2009

[15] M Tamilselvi P KamarajM Arthanareeswari S Devikala andJ A Selvi ldquoDevelopment of nano SiO2 incorporated nano zincphosphate coatings on mild steelrdquo Applied Surface Science vol332 pp 12ndash21 2015

[16] F Fang J-H Jiang S-Y Tan A-B Ma and J-Q JiangldquoCharacteristics of a fast low-temperature zinc phosphatingcoating accelerated by an ECO-friendly hydroxylamine sulfaterdquoSurface and Coatings Technology vol 204 no 15 pp 2381ndash23852010

[17] D R Harris and P Casey ldquoFormulating Surface Coatingsrdquo inActive Protective Coatings vol 233 of Springer Series inMaterialsScience pp 85ndash104 Springer Netherlands Dordrecht 2016

[18] D Grigoriev ldquoAnticorrosion Coatings with Self RecoveringAbility Based on DamageTriggered Micro- and Nanocontain-ersrdquo in Intelligent Coatings for Corrosion Control A Tiwari andetal Eds Butterworth-Heinemann 2015

[19] O Girciene R Ramanauskas V Burokas and A MartusieneldquoFormation of phosphate coatings on steel and corrosionperformance of phosphated specimens in alkaline solutionsrdquoTransactions of the IMF vol 82 no 5-6 pp 137ndash140 2004

[20] R Zeng Z Lan L Kong Y Huang and H Cui ldquoCharacteriza-tion of calcium-modified zinc phosphate conversion coatingsand their influences on corrosion resistance of AZ31 alloyrdquoSurface and Coatings Technology vol 205 no 11 pp 3347ndash33552011

[21] N RezaeeMM Attar and B Ramezanzadeh ldquoStudying corro-sion performance microstructure and adhesion properties of aroom temperature zinc phosphate conversion coating contain-ing Mn2+ on mild steelrdquo Surface and Coatings Technology vol236 pp 361ndash367 2013

[22] MM Jalili S Moradian and D Hosseinpour ldquoThe use of inor-ganic conversion coatings to enhance the corrosion resistanceof reinforcement and the bond strength at the rebarconcreterdquoConstruction and Building Materials vol 23 no 1 pp 233ndash2382009

[23] D Zimmermann A G Munoz and J W Schultze ldquoMicro-scopic local elements in the phosphating processrdquo Electrochim-ica Acta vol 48 no 20-22 pp 3267ndash3277 2003

[24] M Manna A Shah and S V Kulkarni ldquo Development ofphosphate coating on the surface of TMT rebar an option tostudy the effect of n-SiO rdquo Ironmaking amp Steelmaking vol 44no 9 pp 666ndash675 2016

[25] M Sheng Y Wang Q Zhong H Wu Q Zhou and H LinldquoThe effects of nano-SiO2 additive on the zinc phosphating ofcarbon steelrdquo Surface and Coatings Technology vol 205 no 11pp 3455ndash3460 2011

[26] A A al-Swaidani ldquoModified Zinc Phosphate Coatings APromisingApproach to Enhance theAnti-Corrosion Propertiesof Reinforcing SteelrdquoMOJ Civil Engineering vol 3 no 5 2017

[27] D B Freeman Phosphating and Metal Pre-Treatment Wood-head-Faulkner Cambridge UK 1986

[28] S K Rahimi R Potrekar N K Dutta and N R ChoudhuryldquoAnticorrosive interfacial coatings for metallic substratesrdquo Sur-face Innovations vol 1 no 2 pp 112ndash137 2013


[29] J Donofrio ldquoZinc phosphatingrdquo Metal Finishing vol 108 no11-12 pp 40ndash56 2010

[30] H Kunst et al Metals Surface Treatment Encyclopedia ofindustrial chemistry Wiley-VCH Verlag GmbH amp Co KGaAWeinheim 2012

[31] D Weng P Jokiel A Uebleis and H Boehni ldquoCorrosion andprotection characteristics of zinc and manganese phosphatecoatingsrdquo Surface and Coatings Technology vol 88 no 1-3 pp147ndash156 1997

[32] K Ogle A Tomandl N Meddahi and M Wolpers ldquoThealkaline stability of phosphate coatings I ICP atomic emissionspectroelectrochemistryrdquo Corrosion Science vol 46 no 4 pp979ndash995 2004

[33] A Tomandl M Wolpers and K Ogle ldquoThe alkaline stability ofphosphate coatings II In situ Raman spectroscopyrdquo CorrosionScience vol 46 no 4 pp 997ndash1011 2004

[34] M Shoeib M Farouk and F Hanna ldquoInfluence of ethoxylatesurfactants on zinc phosphate coatingsrdquoMetal Finishing vol 95no 9 pp 62ndash68 1997

[35] K Ogle and R G Buchheit Conversion Coatings CorrosionProtection Encyclopedia in electrochemistry 2007

[36] A M al-Swaidani and S D Aliyan ldquoEffect of adding scoria ascement replacement on durability-related propertiesrdquo Interna-tional Journal of Concrete Structures and Materials vol 9 no 2pp 241ndash254 2015

[37] N Kouloumbi G Batis and P Pantazopoulou ldquoEfficiency ofnatural Greek pozzolan in chloride-induced corrosion of steelreinforcementrdquo Cement Concrete and Aggregates vol 17 no 1pp 18ndash25 1995

[38] M I Khan and A M Alhozaimy ldquoProperties of naturalpozzolan and its potential utilization in environmental friendlyconcreterdquo Canadian Journal of Civil Engineering vol 38 no 1pp 71ndash78 2010

[39] M R Moufti A A Sabtan O R El-Mahdy andWM ShehataldquoAssessment of the industrial utilization of scoria materials incentral Harrat Rahat Saudi Arabiardquo Engineering Geology vol57 no 3-4 pp 155ndash162 2000

[40] G K Al-Chaar M Alkadi and P G Asteris ldquoNatural pozzolanas a partial substitute for cement in concreterdquo The OpenConstruction amp Building Technology Journal vol 7 pp 33ndash422013

[41] Y Senhadji G Escadeillas H Khelafi M Mouli and A SBenosman ldquoEvaluation of natural pozzolan for use as supple-mentary cementitious materialrdquo European Journal of Environ-mental and Civil Engineering vol 16 no 1 pp 77ndash96 2012

[42] V Saraswathy SMuralidharan KThangavel and S SrinivasanldquoInfluence of activated fly ash on corrosion-resistance andstrength of concreterdquo Cement and Concrete Composites vol 25no 7 pp 673ndash680 2003

[43] GEMGR ldquothe General Establishment of Geology and MineralResourcesrdquo in Syria (2017) Official document no (3207T9)dated 21112007 (in Arabic)

[44] A Al-Swaidani A Soud and A Hammami ldquoImprovementof the Early-Age Compressive Strength Water Permeabilityand Sulfuric Acid Resistance of Scoria-BasedMortarsConcreteUsing Limestone Fillerrdquo Advances in Materials Science andEngineering vol 2017 pp 1ndash17 2017

[45] A M Neville Properties of concrete Pearson Education Fifth2011

[46] V Horsakulthai S Phiuvanna and W Kaenbud ldquoInvestigationon the corrosion resistance of bagasse-rice husk-wood ash

blended cement concrete by impressed voltagerdquo Constructionand Building Materials vol 25 no 1 pp 54ndash60 2011

[47] A K Parande B Ramesh Babu M Aswin Karthik K KDeepak Kumaar and N Palaniswamy ldquoStudy on strengthand corrosion performance for steel embedded in metakaolinblended concretemortarrdquo Construction and Building Materialsvol 22 no 3 pp 127ndash134 2008

[48] T Ha S Muralidharan J Bae et al ldquoAccelerated short-termtechniques to evaluate the corrosion performance of steel in flyash blended concreterdquo Building and Environment vol 42 pp78ndash85 2007

[49] V Saraswathy and H-W Song ldquoCorrosion performance ofrice husk ash blended concreterdquo Construction and BuildingMaterials vol 21 no 8 pp 1779ndash1784 2007

[50] E Guneyisi T Ozturan and M Gesoglu ldquoA study on rein-forcement corrosion and related properties of plain and blendedcement concretes under different curing conditionsrdquo CementConcrete Composites vol 27 pp 449ndash461 2005

[51] G Xing C Zhou T Wu and B Liu ldquoExperimental study onbond behavior between plain reinforcing bars and concreterdquoAdvances in Materials Science and Engineering Article ID604280 2015

[52] A Poursaee ldquoCorrosion of steel bars in saturated Ca(OH)2 andconcrete pore solutionrdquo Concrete Research Letters vol 1 no 3p 90 2010

[53] Z Panossian ldquoPhosphating of Steel for Cold Forming Pro-cessesrdquo in Encyclopedia of Tribology Q J Wang and Y WChung Eds Springer 2013

[54] A V Sandu C Coddet and C Bejinariu ldquoStudy on the chem-ical deposition on steel of zinc phosphate with other metalliccations and hexamethilen tetramine I Preparation and struc-tural and chemical characterizationrdquo Chemistry Magazine vol63 no 4 pp 401ndash406 2012

[55] H-Y Su and C-S Lin ldquoEffect of additives on the properties ofphosphate conversion coating on electrogalvanized steel sheetrdquoCorrosion Science vol 83 pp 137ndash146 2014

[56] S A Kulinich and A S Akhtar ldquoOn conversion coating treat-ments to replace chromating for Al alloys Recent developmentsand possible future directionsrdquo Russian Journal of Non-FerrousMetals vol 53 no 2 pp 176ndash203 2012

[57] K Abdalla A Rahmat and A Azizan ldquoEffect of copper (II)acetate pretreatment on zinc phosphate coating morphologyand corrosion resistancerdquo Journal of Coatings Technology andResearch (JCTR) vol 10 no 1 pp 133ndash139 2013

[58] A M Al-Swaidani ldquoProduction of more durable and sustain-able concretes using volcanic scoria as cement replacementrdquoMateriales de Construccion vol 67 no 326 2017

[59] B Assouli A Srhiri and H Idrissi ldquoEffect of 2-mercaptoben-zimidazole and its polymeric film on the corrosion inhibitionof brass (6040) in ammonia solutionrdquo Corrosion vol 60 no 4pp 399ndash407 2004

[60] F Belaid G Arliguie and R Francois ldquoCorrosion productsof galvanized rebars embedded in chloride-contaminated con-creterdquo Corrosion vol 56 no 9 pp 960ndash965 2000

[61] M A Arenas C Casado V Nobel-Pujol and J De Dambore-nea ldquoInfluence of the conversion coating on the corrosion ofgalvanized reinforcing steelrdquo Cement and Concrete Compositesvol 28 no 3 pp 267ndash275 2006

[62] L E A Berlouis D A Mamman and I G Azpuru ldquoTheelectrochemical behaviour of copper in alkaline solutions con-taining fluoride studied by in situ ellipsometryrdquo Surface Sciencevol 408 no 1-3 pp 173ndash181 1998

CorrosionInternational Journal of

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Submit your manuscripts atwwwhindawicom


electrolyte diffusion into the metal substrate As a result thecorrosion resistance of the conventional phosphate coating isnot high enough Additives such as Ni2+ Cu2+ Mn2+ Ca2+and Mo2+ and nanoparticles have been extensively used toproduce phosphate coatings with uniform structure lowerporosity higher corrosion resistance and improved adhesionproperties [11 15 21ndash25] A brief state-of-the-art review ofthese additives and their effects on the characteristics of zincphosphate baths has recently been published by the author[26]

Zinc phosphating is essentially an electrochemical pro-cess [27] When the steel comes into contact with phosphatesolution which is basically a phosphoric acid-based solutionan electrochemical reaction takes place Fe2+ ions start todissolve and release electrons at the anodic site and thereduction of H+ occurs at the cathodic site The evolutionof hydrogen and consumption of H+ ions result in a localincrease of pH at the surface leading to precipitation ofzinc phosphate crystals [28] According to Zimmermann etal [23] Donofrio [29] and Kunst et al [30] the possiblereactions taking place in the zinc phosphating bath are asfollows

3Zn2+ + 2H2PO4minus + 4H2O 997888rarr

Zn3 (PO4)2 4H2O (Hopeite) + 4H+

(1)

2Zn2+ + Fe2+ + 2H2PO4minus + 4H2O 997888rarr

Zn2Fe (PO4)2 4H2O (Phosphophyllite) + 4H+

(2)

The alkaline stability of the obtained zinc phosphatecoating on steel is of great importance as it will be embeddedin a highly alkaline environment (pHsim13) Literature showsthat the alkaline stability of zinc phosphate coatings dependson their chemical composition and crystal structure [31]Hopeite (Zn3(PO4)24H2O) has a higher alkaline solubilitythan phosphophyllite (Zn2Fe(PO4)2H2O) [29 32 33] Thusalkaline solutions first dissolve the coating composed ofhopeite Then the dissolution continues for layers rich iniron and those mainly composed of phosphophyllite [34] Ingeneral the presence of phosphophyllite is associated with abetter corrosion resistance than hopeite probably due to itsenhanced chemical stability relative to alkaline electrolytes[35]

Natural pozzolan (NP) is being widely used as cementreplacement due to its ecological economic and perform-ance-related advantageous properties [36ndash41] However itsuse caused a lower alkalinity compared with plain Portlandcement [42] This could be due to the reduction in cementcontent (ie the dilution effect) when adding natural poz-zolan and the consumption of portlandite (CH) through thepozzolanic reaction

Syria is rich in natural pozzolan with estimated reservesof about one billion tonnes [43] There are a significantnumber of studies that deal separately with the effect of usingnatural pozzolan or that of zinc phosphating process on thecorrosion of reinforcing steel However very little or evenno previous works as the author thinks have been carriedout in the past to investigate the combined effect of adding

NP as cement replacement and zinc phosphate coated steelon the anticorrosion properties of reinforcing steel exposedto highly chloride ion concentrations In addition literaturedid not cover the benefit in terms of alkaline stabilitywhich can be achieved when the zinc phosphate coatedsteel is embedded in concrete of relatively lower alkalinityFurther the reduced concrete permeability offered by NP-based cements could be considered an additional physicalbarrier between steel and its environment

The objective of this paper is to investigate the influenceof adding NP as cement replacement on the corrosionperformance of reinforcing steel treated in different zincphosphate baths Four binders with different replacementlevels of NP (0 10 20 and 30) have been producedfor this investigation In addition four zinc phosphatingbaths were employed the first one is a monocation bath (ieit contains only Zn-cation) and three bication baths Zn-Ni Zn-Cu and Zn-Mn respectively Two test environmentswere created for this investigation concrete specimens anda contaminated Ca(OH)2 saturated solution in which thecoated steel was embedded or immersed

The study is of particular importance for the followingpoints

(i) Replacement of OPC by natural pozzolan could sig-nificantly minimize CO2 released into atmosphereand save energy In addition zinc phosphating pro-cess is considered eco-friendly

(ii) This study is the first of its kind in Syria However itis not limited to the country It can be applied to othercountries of similar geology eg Harrat Al-Shamah avolcanic field which covers a total area of some 45000km2 and about 15000 km2 is located in the countryThe rest covers parts of Jordan and KSA

(iii) As our country begins preparations for the hugereconstruction after the war comes to its end theencouraging results can be considered a motivationof other studies for instance use of these localsupplementary cementing materials in enhancementof the anticorrosion properties of reinforced concretemade from recycled concrete aggregates (RCA) RCAare expected to be an inevitable building materialduring the postwar reconstruction in Syria

2 Experimental Procedure

21 NP-Based Concrete Natural pozzolan (NP) used in theexperiments was collected from a Tal Shihan quarry 70 kmsoutheast of Damascus More detailed information related toits characteristics can be found in the latest research work ofthe author and colleagues [44]

Four binder specimens have been prepared one plainPortland cement CEM I (control) and three binary binderswith three replacement levels of 10 20 and 30 NP (EN197-1) 5 of gypsum was added to all the binder specimensThis ratio is frequently used by all Syrian cement plantsproviding about 235 SO3 content The amount of gypsumadded to the cement clinker is expressed usually as the



Rinsing by water





Final drying











(a) (b)




1- Zn2+ Ni2+ Cu2+ Mn2+





14 mm (RB 400) 023 011 054 0006 0009 0001 0001 4887 6382 15






~50

mm

~50

mm

~50 mm ~50 mm

~50 mm~50 mm

(a) (b)

Epoxy coating

Power Supply (~)

45 mm


+ -


Lollipop specimen


15 NaCl solution

200mm

100 mm

100 mm

(c)







120591 =119865

120587Oslash119897(3)





(a)


Reinforcing steel


Unloaded end

Slippage direction

Machine grips

Bond breaker

(b) (c)












0 13 26 39 52 65 78 91 104

Fe LP L

Zn k

Zn k

Fe k

Fe k

P k

Zn L

C k

O k

Si k

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe K Zn K

Fe K Fe K

P K

Si K

C K

Fe LNi K

O K

Ni K

Zn L

P L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe LC K

Fe K

p K

Zn L

Cu L

P L

S K

156k

13k

104k

78k

52k

26k

0



0 13 26 39 52 65 78 91 104

Fe K Zn K

Zn KFe KMn KMn K

P K

Si K

Zn LO K

C KP L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k





0102030405060708090

Curr

ent (

mA

)

50 100 150 200 2500Time (Hour)

NP0NP10

NP20NP30







NP0 421-100 479-100NP10 401-95 469-98NP20 342-81 437-91NP30 323-77 478-89



28 days

NP0 65 172 6278 1265NP10 61 157 5891 1234NP20 48 142 4367 1208NP30 42 111 2915 1201

90 days

NP0 53 144 3971 1257NP10 43 122 3214 1219NP20 29 97 1965 1191NP30 22 68 1112 1193


0

10

20

30

40

50

60

70

80

90

Curr

ent (

mA

)

20 40 60 80 100 120 140 160 1800Time (Hour)





50 100 150 200 2500Time (Hour)

0

10

20

30

40

50

60

70

Curr

ent (

mA

)







0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)





0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

















NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls






Rinsing by water





Final drying











(a) (b)




1- Zn2+ Ni2+ Cu2+ Mn2+





14 mm (RB 400) 023 011 054 0006 0009 0001 0001 4887 6382 15






~50

mm

~50

mm

~50 mm ~50 mm

~50 mm~50 mm

(a) (b)

Epoxy coating

Power Supply (~)

45 mm


+ -


Lollipop specimen


15 NaCl solution

200mm

100 mm

100 mm

(c)







120591 =119865

120587Oslash119897(3)





(a)


Reinforcing steel


Unloaded end

Slippage direction

Machine grips

Bond breaker

(b) (c)












0 13 26 39 52 65 78 91 104

Fe LP L

Zn k

Zn k

Fe k

Fe k

P k

Zn L

C k

O k

Si k

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe K Zn K

Fe K Fe K

P K

Si K

C K

Fe LNi K

O K

Ni K

Zn L

P L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe LC K

Fe K

p K

Zn L

Cu L

P L

S K

156k

13k

104k

78k

52k

26k

0



0 13 26 39 52 65 78 91 104

Fe K Zn K

Zn KFe KMn KMn K

P K

Si K

Zn LO K

C KP L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k





0102030405060708090

Curr

ent (

mA

)

50 100 150 200 2500Time (Hour)

NP0NP10

NP20NP30







NP0 421-100 479-100NP10 401-95 469-98NP20 342-81 437-91NP30 323-77 478-89



28 days

NP0 65 172 6278 1265NP10 61 157 5891 1234NP20 48 142 4367 1208NP30 42 111 2915 1201

90 days

NP0 53 144 3971 1257NP10 43 122 3214 1219NP20 29 97 1965 1191NP30 22 68 1112 1193


0

10

20

30

40

50

60

70

80

90

Curr

ent (

mA

)

20 40 60 80 100 120 140 160 1800Time (Hour)





50 100 150 200 2500Time (Hour)

0

10

20

30

40

50

60

70

Curr

ent (

mA

)







0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)





0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

















NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





(a) (b)




1- Zn2+ Ni2+ Cu2+ Mn2+





14 mm (RB 400) 023 011 054 0006 0009 0001 0001 4887 6382 15






~50

mm

~50

mm

~50 mm ~50 mm

~50 mm~50 mm

(a) (b)

Epoxy coating

Power Supply (~)

45 mm


+ -


Lollipop specimen


15 NaCl solution

200mm

100 mm

100 mm

(c)







120591 =119865

120587Oslash119897(3)





(a)


Reinforcing steel


Unloaded end

Slippage direction

Machine grips

Bond breaker

(b) (c)












0 13 26 39 52 65 78 91 104

Fe LP L

Zn k

Zn k

Fe k

Fe k

P k

Zn L

C k

O k

Si k

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe K Zn K

Fe K Fe K

P K

Si K

C K

Fe LNi K

O K

Ni K

Zn L

P L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe LC K

Fe K

p K

Zn L

Cu L

P L

S K

156k

13k

104k

78k

52k

26k

0



0 13 26 39 52 65 78 91 104

Fe K Zn K

Zn KFe KMn KMn K

P K

Si K

Zn LO K

C KP L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k





0102030405060708090

Curr

ent (

mA

)

50 100 150 200 2500Time (Hour)

NP0NP10

NP20NP30







NP0 421-100 479-100NP10 401-95 469-98NP20 342-81 437-91NP30 323-77 478-89



28 days

NP0 65 172 6278 1265NP10 61 157 5891 1234NP20 48 142 4367 1208NP30 42 111 2915 1201

90 days

NP0 53 144 3971 1257NP10 43 122 3214 1219NP20 29 97 1965 1191NP30 22 68 1112 1193


0

10

20

30

40

50

60

70

80

90

Curr

ent (

mA

)

20 40 60 80 100 120 140 160 1800Time (Hour)





50 100 150 200 2500Time (Hour)

0

10

20

30

40

50

60

70

Curr

ent (

mA

)







0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)





0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

















NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





~50

mm

~50

mm

~50 mm ~50 mm

~50 mm~50 mm

(a) (b)

Epoxy coating

Power Supply (~)

45 mm


+ -


Lollipop specimen


15 NaCl solution

200mm

100 mm

100 mm

(c)







120591 =119865

120587Oslash119897(3)





(a)


Reinforcing steel


Unloaded end

Slippage direction

Machine grips

Bond breaker

(b) (c)












0 13 26 39 52 65 78 91 104

Fe LP L

Zn k

Zn k

Fe k

Fe k

P k

Zn L

C k

O k

Si k

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe K Zn K

Fe K Fe K

P K

Si K

C K

Fe LNi K

O K

Ni K

Zn L

P L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe LC K

Fe K

p K

Zn L

Cu L

P L

S K

156k

13k

104k

78k

52k

26k

0



0 13 26 39 52 65 78 91 104

Fe K Zn K

Zn KFe KMn KMn K

P K

Si K

Zn LO K

C KP L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k





0102030405060708090

Curr

ent (

mA

)

50 100 150 200 2500Time (Hour)

NP0NP10

NP20NP30







NP0 421-100 479-100NP10 401-95 469-98NP20 342-81 437-91NP30 323-77 478-89



28 days

NP0 65 172 6278 1265NP10 61 157 5891 1234NP20 48 142 4367 1208NP30 42 111 2915 1201

90 days

NP0 53 144 3971 1257NP10 43 122 3214 1219NP20 29 97 1965 1191NP30 22 68 1112 1193


0

10

20

30

40

50

60

70

80

90

Curr

ent (

mA

)

20 40 60 80 100 120 140 160 1800Time (Hour)





50 100 150 200 2500Time (Hour)

0

10

20

30

40

50

60

70

Curr

ent (

mA

)







0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)





0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

















NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





(a)


Reinforcing steel


Unloaded end

Slippage direction

Machine grips

Bond breaker

(b) (c)












0 13 26 39 52 65 78 91 104

Fe LP L

Zn k

Zn k

Fe k

Fe k

P k

Zn L

C k

O k

Si k

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe K Zn K

Fe K Fe K

P K

Si K

C K

Fe LNi K

O K

Ni K

Zn L

P L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe LC K

Fe K

p K

Zn L

Cu L

P L

S K

156k

13k

104k

78k

52k

26k

0



0 13 26 39 52 65 78 91 104

Fe K Zn K

Zn KFe KMn KMn K

P K

Si K

Zn LO K

C KP L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k





0102030405060708090

Curr

ent (

mA

)

50 100 150 200 2500Time (Hour)

NP0NP10

NP20NP30







NP0 421-100 479-100NP10 401-95 469-98NP20 342-81 437-91NP30 323-77 478-89



28 days

NP0 65 172 6278 1265NP10 61 157 5891 1234NP20 48 142 4367 1208NP30 42 111 2915 1201

90 days

NP0 53 144 3971 1257NP10 43 122 3214 1219NP20 29 97 1965 1191NP30 22 68 1112 1193


0

10

20

30

40

50

60

70

80

90

Curr

ent (

mA

)

20 40 60 80 100 120 140 160 1800Time (Hour)





50 100 150 200 2500Time (Hour)

0

10

20

30

40

50

60

70

Curr

ent (

mA

)







0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)





0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

















NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





0 13 26 39 52 65 78 91 104

Fe LP L

Zn k

Zn k

Fe k

Fe k

P k

Zn L

C k

O k

Si k

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe K Zn K

Fe K Fe K

P K

Si K

C K

Fe LNi K

O K

Ni K

Zn L

P L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k


0 13 26 39 52 65 78 91 104

Fe LC K

Fe K

p K

Zn L

Cu L

P L

S K

156k

13k

104k

78k

52k

26k

0



0 13 26 39 52 65 78 91 104

Fe K Zn K

Zn KFe KMn KMn K

P K

Si K

Zn LO K

C KP L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k





0102030405060708090

Curr

ent (

mA

)

50 100 150 200 2500Time (Hour)

NP0NP10

NP20NP30







NP0 421-100 479-100NP10 401-95 469-98NP20 342-81 437-91NP30 323-77 478-89



28 days

NP0 65 172 6278 1265NP10 61 157 5891 1234NP20 48 142 4367 1208NP30 42 111 2915 1201

90 days

NP0 53 144 3971 1257NP10 43 122 3214 1219NP20 29 97 1965 1191NP30 22 68 1112 1193


0

10

20

30

40

50

60

70

80

90

Curr

ent (

mA

)

20 40 60 80 100 120 140 160 1800Time (Hour)





50 100 150 200 2500Time (Hour)

0

10

20

30

40

50

60

70

Curr

ent (

mA

)







0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)





0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

















NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





0 13 26 39 52 65 78 91 104

Fe K Zn K

Zn KFe KMn KMn K

P K

Si K

Zn LO K

C KP L

117k

104k

91k

78k

52k

26k

0

65k

39k

13k





0102030405060708090

Curr

ent (

mA

)

50 100 150 200 2500Time (Hour)

NP0NP10

NP20NP30







NP0 421-100 479-100NP10 401-95 469-98NP20 342-81 437-91NP30 323-77 478-89



28 days

NP0 65 172 6278 1265NP10 61 157 5891 1234NP20 48 142 4367 1208NP30 42 111 2915 1201

90 days

NP0 53 144 3971 1257NP10 43 122 3214 1219NP20 29 97 1965 1191NP30 22 68 1112 1193


0

10

20

30

40

50

60

70

80

90

Curr

ent (

mA

)

20 40 60 80 100 120 140 160 1800Time (Hour)





50 100 150 200 2500Time (Hour)

0

10

20

30

40

50

60

70

Curr

ent (

mA

)







0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)





0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

















NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls







NP0 421-100 479-100NP10 401-95 469-98NP20 342-81 437-91NP30 323-77 478-89



28 days

NP0 65 172 6278 1265NP10 61 157 5891 1234NP20 48 142 4367 1208NP30 42 111 2915 1201

90 days

NP0 53 144 3971 1257NP10 43 122 3214 1219NP20 29 97 1965 1191NP30 22 68 1112 1193


0

10

20

30

40

50

60

70

80

90

Curr

ent (

mA

)

20 40 60 80 100 120 140 160 1800Time (Hour)





50 100 150 200 2500Time (Hour)

0

10

20

30

40

50

60

70

Curr

ent (

mA

)







0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)





0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

















NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls







0

10

20

30

40

50

60

Curr

ent (

mA

)

50 100 150 200 250 3000Time (Hour)





0

100

200

300

400

500

600

Cor

rosi

on in

itiat

ion

time (

Hou

r)

















NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls








NP0

Bare steel 821 1423 864 1509ZnP 793 1379 861 1547


NP10

Bare steel 805 1396 875 1551ZnP 787 1381 879 1569


NP20

Bare steel 823 1509 869 1554ZnP 811 1501 91 1569


NP30

Bare steel 851 1534 904 1583ZnP 846 1509 881 1595


ESCE


ZnP BS ZnP-Mn

ZnP-Ni

ZnP-Cu



Bare steelZnPZnP-Mn

ZnP-NiZnP-Cu

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

001

01

1

Curr

ent d

ensit

y (A

cm

2)





(4)






ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls








ZnP-MnZnP


0

10

20

30

40

50Po

lariz

atio

n re

sista

nce (

KOhm

cm2)






4 Conclusions




Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Area 1 (Uncovered

zone)

Area 2

Area 3Ca K

Cr L

Fe KO K


Fe K

Cl KZn L

Fe L


0

26k

52k

78k

104k

13k

156k

182k

208k

13 26 39 52 65 78 91 1040

Ca K

Ca KFe K

Zn K

Zn K

P KZn L

O K

Fe KCa L

Fe K

0

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

Area 3

Zn KFe K

Zn KFe KCa K

Ca K

P K

Zn LO K

C KFe L Si K

Area 2

0

26k

52k

78k

104k

13k

13 26 39 52 65 78 91 1040(a)



Zn휶

Fe

Zn 휶Fe

Zn

Zn

휶Fe

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta

(b)






Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Area 1

Area 2

Area 3

Ni K

P K Ca K

Zn L

O K

Fe K Zn K

Fe K

Ca K

C K

Ni L

Ca L

Zn K

Si KFe L

Ca K

Fe K Zn K

Fe KNi L

Zn LO K

P K

Zn KC K Ca K

Fe L

Area 2

Area 1

Area 3

Ca K

Fe KCa K

Zn K

Zn KCa LNi L

Fe K

O K

Zn LP K

Ni K0

13k

26k

39k

52k

65k

78k

91k

104k

117k

13 26 39 52 65 78 91 10400

13k

26k

39k

52k

65k

78k

91k

104k

13 26 39 52 65 78 91 1040

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

(a)

Ni Nickel

ZnN

i휶

Fe

NiZn 휶FeZn

Ni

휶Fe

Zn

Inte

nsity

0

200

400

600

800

1000

10 20 30 40 50 60 70 80 9002ndasheta



(b)





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Area 3 Area 2

Area 4 Area 1

Ca K

P KZn L

O K

C KCa K Fe K Cu K

Zn K

Cu L

Ca K

Ca K

P K

Fe KCu K

Zn K

Cu L

O K

C K

Zn K

Zn L

Cu KCl KMg K

P K

Cu L

O K

Fe K

Ca K

Cu K

Zn KC KFe K Cu K

Zn K

Zn L

Fe L

Fe k

Ca k

Ca k

P k

Zn L

Cu L

O k

Cu k Zn kC k

Fe LFe k Zn kCu k

013k26k39k52k65k78k91k

104k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104k117k

13k143k

13 26 39 52 65 78 91 1040

013k26k39k52k65k78k91k

104k117k

13k

13 26 39 52 65 78 91 10400

13k26k39k52k65k78k91k

104kArea 1

Area 2

Area 4

13 26 39 52 65 78 91 1040

Area 3

(a)

Cu Copper


ZnCu

휶Fe

Cu

Zn 휶Fe

Zn Zn

휶Fe

Cu

10 20 30 40 50 60 70 80 9002ndasheta

Inte

nsity

0

200

400

600

800

1000



Cu2O

Cu2O Cu

2O

Cu2O

Cu2O

Cu2O

(b)



Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Area 1

Area 3

Area 2

Ca K

P KZn L

O K

Ca L

Mn LCl K

Ca KMn K

Fe K

Fe K

Zn K

Zn KMn K

Ca K

P K

Fe KZn K

O K


Ca L Mn K

Zn L

Fe L

Ca K

P K

Mn KZn K

Mn KCa L

Mn K

O K

Zn L

Zn KFe K026k52k78k

104k13k

156k182k208k234k

26k

13 26 39 52 65 78 91 10400

26k

52k

78k

104k

13k

156k

182k

13 26 39 52 65 78 91 1040

0

13k

26k

39k

52k

65k

78k

91k

104k

0 26 39 52 65 78 91 10413

Area 1

Area 2Area 3

(a)

Zn휶

Fe

Zn

휶FeZn Zn

휶Fe

10 20 30 40 50 60 70 80 9002-eta

Inte

nsity

0

200

400

600

800

1000



(b)











References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls









References




































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls










































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls






Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




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