Study on the Friction and Wear Characteristics of Plasma Sprayed Ni-TiC Coatings with or without Rare Earth Additive

The effect of rare earth ferrosilicon on the friction and wear behaviors of plasma sprayed Ni TiC coating on 12Cr2Ni4A substrate was investigated by means of friction and wear testing, metallographic and scanning electron microscopic observations. The friction and wear testing of the coating sliding against a high speed steel was conducted on a pin on disk tester by simulating the sliding between gear tooth. As the results, the plasma sprayed Ni TiC coatings doped with rare earth ferrosilicon registers lower friction coefficient and is of high compactness as compared with that of coatings without rare earth ferrosilicon. At the same time, the former has considerably higher wear resistance than the latter and records a lower wear volume loss of the counterpart pin as well. It was supposed that a continuous and relatively thinker oxide film was formed on the surface of the coatings containing rare earth ferrosilicon, which helps to keep the frictional pair surfaces off adhesion and contact, subsequently improve the friction reduction behavior and increase the wear resistance of the coatings.