Effect of tribological process parameters on the wear and frictional behaviour of Cr-(CrN/TiN) composite coating: An experimental and analytical study

Abstract

The present study optimizes the tribological parameters for Cr-(CrN/TiN) composite coating on DAC-10 tool steel using the effective concept of Taguchi design. The effect of the most suitable combination of tribological parameters such as applied load, sliding velocity, sliding distance and coolant type on the responses like surface roughness (Ra), friction coefficient (COF) and wear mass loss (WML) was evaluated. The experiment was designed using Taguchi L9 orthogonal array and ANOVA study was conducted to understand the relative effect of the tribological parameters on the responses. The outcomes of the ANOVA study showed that the most significant tribological parameters were coolant type and applied load with average percentage contribution 61.47% and 36.25% respectively followed by sliding velocity (1.26%) and sliding distance (1.02%) which influences the desired responses. With the obtained optimal parameters, confirmatory experiment was conducted to examine the potency of the Taguchi design for the optimization. The results of confirmatory experiment show 45.98%, 38.46% and 32.92% reduction in the value Ra, COF and WML respectively. The desired value for Ra, COF and WML was 2.8 μm, 0.24 and 11.39 mg respectively. SEM micrographs of the worn surface (at optimum condition) show lower wear compared to the worn surface obtained after tribo-test at initial levels of parameter.