Mechanical and Tribological Properties of CrWN Nanostructured Hard Films

Abstract

This work determines optimal settings for the deposition parameters of CrWN hardened, nanocomposite films grown on tungsten carbide tools and glass substrates with direct current (DC) reactive magnetron co-sputtering. Using metallic Cr and W targets, argon was the plasma gas and nitrogen was the reactive gas. An orthogonal array, the signal-to-noise ratio and analysis of variance are together used to analyze the effect of the deposition parameters. The Taguchi method was used to design a robust experiment. Then deposition parameters of the CrWN hard films, including Cr DC power (Watts), W DC power (Watts), N2/(Ar+N2) flow-rate ratios (%) and deposition time (min) were optimized with reference to structure of the films, dry turning tests of AISI 316 stainless steel (50 mm diameter) and wear tests of CrWN films. This study uses a grey-based Taguchi method to determine the parameters of the coating process for CrWN hard films by considering multiple performance characteristics. In the confirmation runs, according to grey relational analysis, improvements were noted of 6.17% in the surface roughness, 26.27% in the flank wear, and 6% in the coefficient of friction. The wear resistance of CrWN films can be evaluated by considering the other mechanical properties, including elastic recovery, hardness and Young’s modulus, which are obtained from the nanoindentation testing.