Tribological performance of thermally sprayed cermet coatings containing solid lubricants

Protective WC–10Ni cermet coatings containing a small portion of solid lubricant [MoS2, WS2 or fluorinated ethylene propylene (FEP teflon)] for use in wear applications needing a low coefficient of friction were investigated in this study. These coatings were deposited on stainless steel substrates using the HVOF thermal spray process. The solid lubricant powders were added to the WC–10Ni cermet powder and mechanically mixed prior to the deposition. The performance of each coating was evaluated using a sliding wear test on a carbon-graphite counterpart to measure the coefficient of friction and the wear rate. The addition of solid lubricants to the cermet coating did not change significantly the coefficient of friction when sliding against carbon-graphite but the wear rate of both rubbing parts was greatly influenced.