HVOF Thermal Spray TiC/TiB2 Coatings for AUSC Boiler/Turbine Components for

Enhanced Corrosion Protection

US DOE Project Number: DE-FE0008864Project Officer: Richard Dunst

Principal Investigator: Kanchan MondalSouthern Illinois University Carbondale

Co-Principal Investigator: Rasit KocSouthern Illinois University Carbondale

Co-Principal Investigator: Chinbay FanGas Technology Institute, Des Plaines

2016 Crosscutting Research & Rare Earth Elements Portfolios Review Apr 18-22, 2016

Presenter: Chung-Ying TsaiSouthern Illinois University Carbondale

Kanchan MondalPrincipal Investigator

Rasit KocCo-Principal Investigator

Rasit KocPowder Synthesis

Kanchan MondalParticle Characterization

Corrosion Studies

Zhezhen FuPh. D. Student

Chinbay Q FanCo-Principal Investigator

Chinbay Q. FanHVOF coating

Chung-Ying TsaiPh. D. Student

Ronald StanisResearcher

PROJECT TEAM

Adam SimsPh. D. Student

HVOF, Flame Spray Coatings

GTI project number 21397Chinbay Fan and Ronald Stanis

Background

0

10

20

30

40

50

60

0

200

400

600

800

1000

1200

Subcritical AdvancedSupercritical (270bar/600C/620C)

AUSC (350 bar/700C/720C)

AUSC with Feedwater heating

optimized

Cycl

e Ef

ficie

ncy/

CO2

Redu

ctio

n (%

)

CO2

Emiss

ions

(kg/

Mw

e-hr

)

CO2 Emissions (kg/MWe-hr)

Cycle Efficiency (% LVH)

CO2 reduction compared to subritical plants

• High Temperature, High Pressure, Supercritical water

• Mechanical Strength– Max Allowable Stress– Creep Rupture Stress– Fatigue Resistance

• Corrosion Resistance– Fireside Corrosion

• Thermal conductivity• Low coefficient of expansion• Manufacturing process issues such as

weldability and fabricability

0

50

100

150

200

250

300

450 500 550 600 650 700 750 800

Cree

p Ru

ptur

e St

ress

, Mpa

Metal Temperature, oC

Super 304H 347 HFG Sanirco 25Alloy 617 Alloy 263 Inconel 740SAVE 12 T23 T24P92

Substrate Material Class Applicable Component1 Super 304H Austenitic SH/RH tubes2 Sarnico 25 Austenitic SH/RH tubes3 HR3C Austenitic SH/RH tubes

4 STD617/CCA 617 Nickel Alloy Tubing, HP turbine-casing, piping, rotor -700 oC

5 Haynes 230 Nickel Alloy SH tubes, HP turbine rotor – 700oC

6 Inconel 740 Nickel Alloy SH tubes, HP turbine - casing, piping, rotor-760 oC

7 P91/P92 Ferritic Low Temp SH/RH

8 T91/T92 Ferritic Low Temp SH/RH, HP turbine piping –620oC

9 430 Ferritic Boiler Tubes10 T23/T24 Ferritic Furnace Tubes

Substrates of Interest

Carbothermal Process for TiC and TiB2 Powder Synthesis

100 nm

Fuel Flexible: H2, Acetylene,Kerosene…Oxidant Flexible: O2 or Air

GTI HVOF Flame Spray System

SS 304H As received After surface roughening

Water honing

Safety is first priorityHearing protectionEye protection (light)Face ShieldFlame arrestorsTwo person operation

One holding gunOne operating gas flows

Emergency Stop Button

KT3KT4

Slide 7

KT3 TiC mp 3260HVOF- up to 3300 when H2 introduced.Kyle T, 4/18/2016

KT4 Hydrogen and oxygen are mixed together and combust causing the powder material to become molten.Velocity ranges from 600-100 m/sKyle T, 4/18/2016

Flame Only

Flame with Powder

Partially Covered SamplesSpray Deposition

SS 304H C(0.04-0.1) Si(0.75) Mn (2) P (0.045) S (0.03) Cr (18-20) Ni (8-10.5)SS 430 C(0-0.12) Si (0-1) Mn (0-1) Cr(16-18) Ni(0)P91 C(0.08-0.12) Si(0.2-0.5) Mn (0.3-0.6) Mo (0.8-1.05) Cr(8-9.5) Ni(0.4 max)

62.59%0.83%34.43% 1.86% 0.29%

P91

500 µm

430

Fe OCr Mn

61.06%9.69%27.82% 1.32% 0.10%

S

500 µm

7-Days 750 ⁰C Simulated Flue Gas Corrosion Test

Pristine 430 and P91 Steels: Corrosion Behavior

430

FeO Cr S

Fe OCr SMo

20 µm

200 µm

P91

FeO Cr SMo

Pristine 430 and P91 Steels: Corrosion Behavior

7-Days 750 ⁰C Simulated Flue Gas Corrosion Test

KT1KT2

Slide 10

KT1 The surface of the steel was initially covered with Cr2O3, which was then converted to FeCr2O4, and finally Fe3O4 and Fe2O3 formed on it. These results indicated that the reason for the breakaway oxidation in type 430 stainless steel is Cr depletion beneath Cr2O3 layerand the subsequent ionisation of Fe, not the simple mechanical failure of Cr2O3.Kyle T, 4/17/2016

KT2 Hematite (Fe2O3) occurs on the inner surface of the tube. Then magnetite (Fe3O4) appears below hematite. Going deeper into the layerthere is a spinel, i.e. a mixture of magnetite and chromite.Kyle T, 4/17/2016

Fe

O

Cr

P91 Matrix

200 µm90 µm45 µm

Mo S

7-Day 750 ⁰C Simulated Flue Gas Test: P91 Substrate

Depth from Surface (µm)

Atom

ic A

mou

nt

0 430

550 ⁰C50 µm

650 ⁰C50 µm

750 ⁰C200 µm

FeO Cr S

7-Day Simulated Flue Gas Test: P91 Substrate

62.59% 0.83%34.43% 0.29%

Fe Cr SO

PristineP91

0.04%1.08%

24.94%

73.70% 0.15%

Fe Cr SO

TiBSE

Ti CoatedP91

7-Day 750 ⁰C Simulated Flue Gas Test: Ti Coated P91 Substrate

200 µm FeO Cr S

10 µm FeO Cr SMoTi

PristineP91

Ti CoatedP91

7-Day 750 ⁰C Simulated Flue Gas Test: Ti Coated P91 Substrate

CrSMo

Ti Fe

O

0 49

Ti Coating P91 Matrix28 µm ~4 µm

7-Day 750 ⁰C Simulated Flue Gas Test: Ti Coated P91 Substrate

Depth from Surface (µm)

Atom

ic A

mou

nt

Pristine P91

7-Day 700 ⁰C H2O + O2 Corrosion Test on P91 Substrates

30 µm

30 µmFeO CrTi

Ti Coated P91

FeO Cr

7-Day 700 ⁰C Air Corrosion Test on P91 Substrates

Pristine P91

50 µm

Ti Coated P91

10 µm FeO CrTi

FeO Cr

XRD Results of Ti Coated and Pristine P91 After Corrosion Tests

H2O + O2

Sim Flue Gas

Ti Coated-Sim Flue Gas

O2

◊ ◊ ◊◊ ◊ ◊ ◊

XX

Inte

nsity

Δ Δ ΔΔΔΔ

ΔΔΔ

Δ Δ

◊ ◊◊ ◊ ◊ ◊ ◊

◊ ◊ ◊ ◊ ◊ ◊ ◊

Δ- Rutile ◊- Hematite X- Fe-Cr

Impact of Coating Density on Corrosion Resistant

10 µm FeO Cr SMoTi

50 µm FeO Cr SMoTi

Dense Coating

LooseCoating

Ti MetalCoated

TiCCoated In

tens

ity

ΔΔ

ΔΔΔ

Δ

ΔΔ

ΔΔ

Δ

10 µm

Ti MetalCoated

10 µm

TiCCoated

BSE Ti Fe

BSE Ti Fe

Δ- Rutile

HVOF Coatings: TiC and Ti Metal

Achievements

HVOF thermal spray coating of the prepared powders on P91 steel substrates.

Corrosion characterizations of pristine and coated P91 steels.

Increased longevity and corrosion resistance of the coated substrates subjected to fireside corrosion in AUSC SH/RH tubes and boiler tubes.

Acknowledgement

Thank You

US DOE Project Number: DE-FE0008864Project Officer: Richard Dunst