Comparison of the tribological characteristics of titanium nitride and titanium carbonitride coating films

The tribological parameters are composed of specimens coated with titanium film as underlayer, and different ceramic materials as top layers. Titanium nitride (TiN) film or titanium carbonitride (Ti(C,N)) film of different thicknesses was deposited as the top layer using the cathodic are ion plating technique. We address the influence of the thickness of the two different coating layers on the friction coefficient, wear rate, adhesion strength, wear mechanism, microhardness and temperature of the specimen, and the effect of sliding speed on both the friction coefficient and wear rate. Increasing sliding speed results in a significant decline in both the wear rate and friction coefficient. For specimens with the same coating layer thickness, higher temperatures were obtained with the Ti(C,N) coating, even when there was a relatively lower accompanying friction coefficient. The decrease in adhesive strength caused by increasing the top layer thickness is evidently higher than that caused by increasing the underlayer thickness. If the thickness of the underlayer is held constant, the specimen microhardness increases with increasing top layer thickness. If the thickness of the top layer is held constant, whichever material was coated as the top layer, increasing the underlayer thickness decreases the microhardness.