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SERDP Plasma ID update. 21st HCAT Program Review Toronto, September 26, 2002. Program objective. Develop plasma spray for smooth, low porosity coatings for IDs standard, small particle, nanoagglomerates Evaluate new miniature guns for minimal spray diameter. How it all fits together.
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SERDP Plasma ID update 21st HCAT Program Review Toronto, September 26, 2002
Program objective • Develop plasma spray for smooth, low porosity coatings for IDs • standard, small particle, nanoagglomerates • Evaluate new miniature guns for minimal spray diameter
Findings so far • Nanoagglomerate WC-Co is not really commercially available • therefore cannot be used • Minimum ID that can be coated with good properties is 2.5 - 3” • coatings are high rate, so ideal for landing gear and utility actuators • Sulzer Metco may evaluate new, smaller F 300 gun • T 400, WC-12Co, WC self-fluxing (WC12Co)33Ni9Cr3.5Fe2Si2B2.5C now optimized • Latest WC-Co and self-fluxing look very good
Sample holder Pull test Metallography Corrosion Almen Wear Sulzer F 210 Praxair SG 2700
NRC standard polishing procedure(Jean-Gabriel Legoux) Cutting high speed diamond wheel Mounting vacuum infiltration Polishing SiC grind 9m diamond, 3m diamond OP-A acidic alumina Measurement of porosity a) vacuum mount, b) Bakelite hot mount (smears) 6.4% porosity 2.7% porosity
T400 coating Tube overspray 3” ID 7” long 0.0165” thick 600 ” Ra 0.0115” thick 300 ” Ra Issues to be resolved • Tube rotates, spray head goes in and out
ID vs OD spray microstructure WC-Co 38m powder, 60 OD spray, 3% porosity WC-Co 38m powder, 60 ID spray, 9% porosity • Overspray incorporates into coating as go down tube • Additional air jets to blow overspray powder away under test at Praxair
Are guns different? • Sulzer Metco gun has additional gas sources to cool gun • appears to be effective in blowing out more overspray • Will be checking the different guns and making mods to gas flow as necessary • NRC has made “FumeSpector” dust storm monitor
To be done next few months • Minimize overspray incorporation • Spray test samples using holder • Property and performance testing • metallography, adhesion, Almen, • wear, abrasion, corrosion, fatigue