Evaluation of Gamma irradiated Ti6Al4V and Silver alloyed a-C coatings as friction pair via Response Surface Methodology

Abstract

ABSTRACT The present study discusses a possible friction pair of silver alloyed a-C-coated stainless steel 316 LVM and gamma-irradiated Ti6Al4V alloy for application in medical implants. The morphology and structure of the materials were studied using AFM and XRD analysis respectively. The experiments for the dry-simulated tribotest were designed using Box-Behnken design (BBD)- based L15 array. ANOVA analysis was performed to evaluate the influence of design parameters (applied load in N, sliding velocity in m/s and sliding distance in m) on the response variables (surface quality, friction coefficient, mass loss in the coating and Vickers microhardness). The optimum wear parameters obtained using BBD was 5.75 N, 0.1 m/s and 1515 m. What is more, the worn surface analysis of the gamma-irradiated Ti6Al4V indicated grooving and scuffing as primary wear mechanism whereas the coated surface witnessed mild abrasion. The XRD pattern propounded the formation of TiO2 oxide layer on the surface of the pin. Raman studies on the worn silver alloyed a-C-coated surface indicate no statistically significant loss in the structural make-up of the coating. During sliding, the silver-alloyed a-C- coated surface and gamma-irradiated Ti6Al4V counterbody suffered three-body wear mechanism.