FRICTION AND WEAR PERFORMANCE OF AN ELECTROSPARK-DEPOSITED Ta COATING ON CrNi3MoVA ST

Abstract

A Ta coating was prepared on a CrNi3MoVA steel substrate by means of electrospark deposition (ESD) and its friction and wear performance was investigated. The nanomechanical properties and friction coefficient were tested by employing a nanoindenter and a friction and wear testing machine, respectively. Moreover, the phase structure was obtained using X-ray diffraction (XRD), and the morphology and composition were analysed before and after friction utilizing scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that the gradient Ta coating with nanocrystals is composed of -Ta and Fe-Ta intermetallics, and Ta2O5 and -Fe phases. The hardness of the Ta coating increased by 115 % compared to that of the CrNi3MoVA steel and its elasticity was reduced by 21 %. The friction coefficient of the Ta coating was reduced by 81 % compared to that of the CrNi3MoVA steel and its weight loss was reduced by 89 %. The wear mechanism of the Ta coating can be characterized as slight adherence, whilst that of the CrNi3MoVA steel includes severe adherence and fatigue.