Mechanical and friction behavior of sputtered Mo-Cu-(N) Coatings under various N2 gas flow using a multicomponent single alloy target

Abstract

Mo–N based coatings have attracted increasing attention as protective coatings for mechanical components owing to their superior mechanical performance. In this study, ternary (binary) Mo–Cu–(N) nanocomposite coatings are prepared at various N2 gas flow rates by direct current magnetron sputtering using a multicomponent single alloy target. The microstructure, morphology, mechanical properties, and friction behavior of the coatings are characterized. The friction and wear behavior of the coatings prepared at various nitrogen gas flow rates are measured under different lubricant environments such as 5W30 with MoDTC additive and polyalphaolefin. The composition of the coatings is found to be nearly similar to that of the target regardless of the nitrogen content, but the microstructure showed significant changes. In this study, Mo–Cu–(N) nanocomposite coating obtained under N2 gas flow rate of 6 sccm exhibits the best mechanical property and friction performance under harsh environments (100 N, 150 °C) owing to the presence of hard MoxN phase with a grain size of approximately 6.43 nm and Cu phase. The extremely low friction coefficient of 0.003 is attributed to the interaction of the coating and oil/counterpart components during the friction test under the polyalphaolefin lubricant environment.