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ADVANCED PARTICLE ADVANCED PARTICLE CHARACTERIZATION FOR CHARACTERIZATION FOR
IMPROVED UNDERSTANDING IMPROVED UNDERSTANDING OF SPRAY COATING QUALITYOF SPRAY COATING QUALITY
E. PirardE. PirardUnivUniv. Liège (Belgium). Liège (Belgium)
F. Campana, J-P F. Campana, J-P JanssenJanssen
Advanced Coating, Liège (Belgium)Advanced Coating, Liège (Belgium)
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
IntroductionIntroduction
The interaction between the gas and the The interaction between the gas and the individual particle plays a key roleindividual particle plays a key role
A better understanding of the way individual A better understanding of the way individual particles are affected, will allow for developing particles are affected, will allow for developing more accurate powder specificationsmore accurate powder specifications
Existing norms provide only limited insight into Existing norms provide only limited insight into particle characteristicsparticle characteristics
Use innovative single particle digital imaging Use innovative single particle digital imaging and analysis to access pertinent informationand analysis to access pertinent information
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
Metal PowdersMetal Powders High velocity oxy-fuel (HVOF) spray coatings with High velocity oxy-fuel (HVOF) spray coatings with
four (Crfour (Cr33CC22-NiCr 75/25) comparable powders :-NiCr 75/25) comparable powders :
A B C D
SupplierSulzer Metco
Sulzer Metco Sylvania
Deloro Stellite
Size Range [µm] [-45+15] [-45+15] [-53+10] [-53+10]Flowability 50g
[sec.] N.A. 18,26 26 23App. density
[g/cm3] N.A. 3,67 3,6 3,62Carbon (%) 9,64 9,48 9,11 9,45
Manuf. Process A/S A/S/P.D. A/S/P.D. A/S/P.D.supplier data
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
Standard CharacterizationStandard Characterization ISO 3923/2: Determination of apparent densityISO 3923/2: Determination of apparent density
Part 2: Scott volumeter methodPart 2: Scott volumeter method
DensityDensity A B C D
Test 1 2,77 3,82 3,79 3,84
Test 2 2,75 3,87 3,79 3,8
Test 3 2,76 3,82 3,78 3,78
m 2,76 3,84 3,79 3,81
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
Standard CharacterizationStandard Characterization ISO 4490 : Determination of flow time by means of a ISO 4490 : Determination of flow time by means of a
calibrated funnel (Hall flowmeter)calibrated funnel (Hall flowmeter)
FlowFlow A B C D
Test 1 29,59 22,15 29,29 21,78
Test 2 29,73 22,23 29,37 21,18
Test 3 29,66 22,28 28,75 21,79
m 29,66 22,22 29,14 21,58
Suppl. data N.A. 18,26 26 23
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
Particle ImagingParticle Imaging
Particle AnalysisParticle Analysis
Digital Image Analysis Digital Image Analysis ofof
Individual ParticlesIndividual Particles Three essential steps requiring dedicated Three essential steps requiring dedicated
solutions :solutions :
Powder DispersionPowder Dispersion
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
Powder DispersionPowder Dispersion
Patented vacuum disperserPatented vacuum disperser Cylindrical chamberCylindrical chamber Pinhole with plastic membranePinhole with plastic membrane Settling onto circular glass slideSettling onto circular glass slide
AdvantagesAdvantages Perfect dispersion (1:500)Perfect dispersion (1:500) No breakage / deformation of No breakage / deformation of
particlesparticles Controlled (symmetrical) Controlled (symmetrical)
segregationsegregation
Occhio InstrumentsOcchio InstrumentsVDD270VDD270
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
Particle ImagingParticle Imaging
Occhio InstrumentsOcchio Instruments ALPAGA 500 nanoALPAGA 500 nano
Automated Digital MicroscopyAutomated Digital Microscopy Diascopic illumination @ 439nm Diascopic illumination @ 439nm
(LED)(LED) Superzoom telecentric lensSuperzoom telecentric lens Hi-resolution digital videoHi-resolution digital video Fully motorized glass plateFully motorized glass plate
AdvantagesAdvantages Typ. 10.000 particles/minTyp. 10.000 particles/min Controlled particle position and Controlled particle position and
velocityvelocity Dynamic range : 0,5 µm – 200 µmDynamic range : 0,5 µm – 200 µm
15 µm
a 15 µm particle is typically 800 pixels
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
Particle AnalysisParticle Analysis Accurate estimation of a “sieving diameter”Accurate estimation of a “sieving diameter”
ISO TC24SC4 : ISO TC24SC4 : Sizing by methods other than sievingSizing by methods other than sieving
Application oriented shape characterizationApplication oriented shape characterization Computation of a wear index :Computation of a wear index :
Computation of a satellity index :Computation of a satellity index :W 46,18 64,14 65,71 82,55
RND 99.6 % 97.2 % 66.7 % 61.6 % 50.9 %
EL 0.78 18.64 5.65 17.51 12.67
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
Results on Results on CrCr33CC22-NiCr 75/25 particles-NiCr 75/25 particles
Size DistributionsSize Distributions By Number of by VolumeBy Number of by Volume Sub-sieve analysis capabilitySub-sieve analysis capability
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
ResultsResults
MorphostatisticsMorphostatistics Quality control statisticsQuality control statistics Discriminant statisticsDiscriminant statistics
DIN
[µm]W [%]
RoundnessEl [%]
Elongation
A 33,66 65,67 25,68
B 33,35 74,83 21,70
C 28,97 58,29 21,70
D 30,02 79,00 16,10
Mean values
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
ResultsResults
Coating Deposition EfficiencyCoating Deposition Efficiency
Q Fl Th/r Th/p/Flg/(m²x0.1mm)
g/min µm µm/(g/min)
A1 Mean 1.184 39 11.8 0,3Std Dev 70 5.4 1.8 0,03
A2 Mean 1.252 38.1 11.4 0,3Std Dev 244 2.1 1.6 0,05
DMean 1.381 45.5 12.2 0,27Std Dev 142 7.3 1.3 0,05
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
ResultsResults
Coating Deposition EfficiencyCoating Deposition Efficiency
Th [µm]
Porosity Hardness [HV0,3]
Mean Min. Max. Mean Min. Max.
A 183 2,6% 2,1% 3,8% 1041 845 1255
D 159 1,1% 0,4% 1,4% 971 856 1173
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
Discussion & ConclusionsDiscussion & Conclusions Image analysis provides very accurate size Image analysis provides very accurate size
distributionsdistributions Perfect correlation with sievesPerfect correlation with sieves Number weighted distributions are unique Number weighted distributions are unique (e.g. A contains 90% (e.g. A contains 90%
<15µm)<15µm)
Image analysis provides unique shape information Image analysis provides unique shape information that correlates perfectly with flowability teststhat correlates perfectly with flowability testsDIN
[µm]W [%]
Roundness
El [%]
Elongation Scott Hall
A 33,66 65,67 25,68 2,76 29,66B 33,35 74,83 21,70 3,84 22,22C 28,97 58,29 21,70 3,79 29,14D 30,02 79,00 16,10 3,81 21,58
ITSC Seattle 15-18 May 2006ITSC Seattle 15-18 May 2006 PirardPirard (Univ. Liège), (Univ. Liège), CampanaCampana & & JanssenJanssen (Advanced Coating ) (Advanced Coating )
PerspectivesPerspectives
Image analysis offers a unique insight into metal Image analysis offers a unique insight into metal
powder properties (direct measurement !).powder properties (direct measurement !).
It opens the way to a better understanding of It opens the way to a better understanding of
coating qualities with respect to powder coating qualities with respect to powder
propertiesproperties
This new analytical technology allows to optimize This new analytical technology allows to optimize
powder specifications.powder specifications.
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