Effects of constituent layers and interfaces on the mechanical and tribological properties of metal (Cr, Zr)/ceramic (CrN, ZrN) multilayer systems

Abstract

The influences of constituent layers and interfaces on the mechanical and tribological behaviors of metal (Cr, Zr)/ceramic (CrN, ZrN) multilayer coatings were systematically investigated in the present study. Four sets of multilayer coatings (Cr/CrN, Cr/ZrN, Zr/CrN and Zr/ZrN) with the same number of interfaces were synthesized by multi-arc ion plating technique. The crystalline structures of the multilayer coatings were determined by X-ray diffraction and morphologies were observed by scanning electron microscope and transmission electron microscope. Furthermore, the nanoindenter, Vicker indenter, scratch tester and ball-on-disk tribometer were employed to evaluate the hardness, indentation toughness, adhesion strength and tribological properties of as-prepared coatings, respectively. Results revealed that the multilayer coatings with different constitute layers and interfaces presented different microstructures and properties. Based on the analysis of the cross-sectional indentation topographies, Zr interlayers exhibited higher crack resistances compared to Cr interlayers. Zr/CrN multilayer coating showed the highest hardness of 28 GPa, the strongest strength adhesion (>100 N) and the lowest wear rate. The excellent tribological performance of Zr/CrN multilayer coating was mainly ascribed to the high crack resistance of Zr layer, high wear-resistant layer of CrN as well as the local coherent interface between Zr and CrN sublayers.