Structural, mechanical and tribological properties of nanostructured CN{sub}x/TiN multilayers

摘要

Nanostructured CN{sub}x/TiN multilayers were deposited onto Si(l 00) and M42 high-speed steel substrates using closed-filed unbalanced magnetron sputtering. The deposition process was controlled by a closed-loop optical emission monitor (OEM) to regulate the flow of N{sub}2 gas. Different carbon nitride Λ{sub}(CN{sub}x) layer thicknesses could be attained by varying the C target current (0.5-2.0A). OEM settings and bilayer thickness periods (i.e. Λ{sub}(CN{sub}x) = 0.3-1.2nm, while Λ{sub}(TiN) = 3.0nm) significantly affected the mechanical and tribological properties of CN{sub}x/TiN multilayer films. XPS analyses revealed that the chemical states, such as TiN, TiC, TiN{sub}xO{sub}y ???????????and TiO{sub}2, existed in a TiN layer. The nanohardness of the film with bilayer thickness Λ{sub}(TiN) = 3.0 nm and Λ{sub}(CN{sub}x) = 0.9 nm was ～41.0GPa. The residual compressive stress was found to be between 1.5 and 3.0 GPa. By the scratch test, the critical load value obtained was high ～78 N. Rockwell-C adhesion tests exhibited the best adhesion and cohesive strength for multilayers with Λ{sub}(TiN) = 3.0 nm, Λ{sub}(CN{sub}x) = 0.3 and 0.6 nm. The friction coefficient of a multilayer was found to be low 0.11. Lower frictional coefficients and wear rates were the consequences of the increase in Λ{sub}(CN{sub}x), which provided a lubricating function in the multilayers.