Keith Legg Summary of coating integrity and planned testing HCAT Program Review August 2001 Toronto

Keith Legg Big bar tests at NAWC, PAX River n #6, R= -1, WC-Co 0.012” ä Failed at 180 ksi n #2, R= -0.33, WC-Co 0.012” ä Test ksi 20 cycle  Failed at 200 ksi n R= -1, WC-Co 0.003” ä Passed 220 ksi #6 #2 Very sensitive to thickness. Insensitive to R Very sensitive to thickness. Insensitive to R Big bars not much different to small

Keith Legg Hill AFB re-optimization WC-Co looks good to 240 ksi, R=-0.5 Note failures at higher substrate T, lower dep rate WC-CoCr WC-Co, 3 pts WC-Co fail We can make 0.005”, 0.015” WC-Co coatings that do not spall at 240 ksi, R=-0.5

Keith Legg Latest data from 40 specimens coated at Southwest Aero, 0.003”, 100 cycles at each load to 240 ksi S R=-0.5 M5-7, WC-CoCr fullM5-17, WC-CoCr patch M5-28, WC-Co patch M5-37, WC-Co full 190Subsurface*SubsurfaceNone 51 cyclesSubsurfaceNoneSubsurface & bulging** 210Crack, no cycles, some subsurface Same 220Crack, no spalling Same 230Crack, no spalling Crack, some bulging** Same 240Nf=3046 cycles, fracture Nf=3004 cycles, fracture Nf=3368 cycles, spalling 72 cycles, Nf=3716 cycles WC-CoCr survived to 240 ksi and exceed Nf Does this mean WC-CoCr is not a lot more brittle than WC-Co? WC-CoCr survived to 240 ksi and exceed Nf Does this mean WC-CoCr is not a lot more brittle than WC-Co?

Keith Legg Ogden ALC A-10 LG bend tests, R= ” WC-Co deposited at OO-ALC using new parameters  500 cycles at loads to 190 ksi  ultrasonic tests showed no delamination  50 cycles at loads >190 ksi  no spalling at 240 ksi (yield)  coating spalled at 256 ksi (>yield) 0.015” WC-Co  spalled at low load - cause unknown We can reach 240 ksi with thick coating Is spalling very sensitive to thickness? We can reach 240 ksi with thick coating Is spalling very sensitive to thickness?

Keith Legg Conclusions to date WC-Co and WC-CoCr can both exceed commercial requirements for OEM coatings (0.003”) WC-Co can exceed Air Force (land-based aircraft) requirements for rebuild coatings Spalling appears most sensitive to  deposition conditions (how it is optimized)  coating thickness Spalling appears not very sensitive to  sample diameter (details of coating morphology)  R ratio (once you get interface cracking it does not need a big push to delaminate) WC-Co looking likely to work for all but high-bend parts

Keith Legg Work to be done Additional testing  Additional samples and big bar tests at NAWC  New samples and big bar tests at Metcut and AFRL  Bend tests to examine D/T ratios at Hill  Additional A-10 bend tests at Hill  Bending fatigue of large cylinders at Goodrich Process mapping  Coatings can exceed requirements - let’s make sure we know how to ensure they always do! Consideration of rebuild options  Ensure coating integrity through deposition control  Duplex coatings (alloy build-up, carbide cap)  e.g. Long Beach Joe Kolek reported Tribaloy does not crack - is it a good rebuild, or is NiAl better (cc sulfamate Ni)?