Tribological performance of ceramic-based films under different tribo-test media and vacuum conditions

The influence of different ceramic-based coatings on the adhesion and wear resistance of M2 high-speed steels has been investigated under different tribo-test conditions. For this purpose, TiN, CrN, and DLC films were deposited on the substrates and silicon wafers by a magnetronsputtering PVD system. Structural, mechanical, and tribological properties of coated samples were examined with SEM, XRD, tribotester, microhardness and scratch tester. The sliding wear tests were performed under air, dry nitrogen, oil, and vacuum environments. It was seen that the highest hardness and residual stress values were obtained from the TiN-coated samples, while the lowest hardness and residual stress values were seen in the CrN-coated specimen. It was determined that the hardness and residual stress values of the coating were the most effective parameters between film and substrate adhesion. Therefore, it was observed that high hardness and residual stress had negative effects on critical load values. Tribological tests showed that the wear and friction behaviors differed from each other according to the coating type and tribo-test conditions. Both the lowest friction coefficient values and wear rates were obtained from the oil tribo-test environment. The lowest friction coefficient and wear rate values were achieved in DLC-coated samples.