Spall Resistant HVOF Coatings
D. Webb, R. Vander Straten
ES3, Clearfield Utah
Brad Martin
417th SCMS/GUEA, Hill AFB Utah
Abstract
The Under Secretary of Defense mandated all DoD facilities reduce or eliminate Hexavalent Chrome from all processing environments. The USAF Landing Gear Systems Engineering located at Hill AFB Utah is converting all line of sight EHC plating to High Velocity Oxygen Fuel (HVOF) applied tungsten carbide-cobalt (WC/Co) and/or tungsten carbide-cobalt chrome (WC/Co/Cr) coatings. The original HVOF coating thickness of 0.015 inch has been reduced to 0.010 inch due to spallation concerns. This has resulted in the condemnation of many expensive assets due to this coating thickness reduction. ES3 is developing an HVOF applied spall resistant coating for the USAF that may be applied up to 0.030 inch for High Strength Steels (HSS) above 200 KSI stress levels. Material test data and recommendations for use are detailed in this paper.