Investigation on the effects of pretreatment on the surface characteristics of duplex plasma-treated AISI P20 tool steel

Abstract

Plasma nitriding (PN) coupled with physical vapor deposition (PVD) has emerged as one of the promising surface treatments to achieve an elevation in the tribological, oxidation resistance, and load-bearing ability of the engineering materials in recent years. However, the consequential impact of heat treatment processes implemented upon the base substrate on enhancing the wear resistance of such materials cannot be disregarded. In the present study, AISI P20 steel samples in as received and heat-treated conditions were selected for the investigation to establish the influence of pretreatment prior to the duplex treatment through microstructural, phase and compositional characterizations carried out by the means of XRD, SEM and EDS analysis followed by surface roughness and microhardness tests. Heat-treated samples were observed to bear higher hardness than the as-received ones, while surface roughness evaluations indicated a reversed behavior. Further, tribological investigations were conducted for an accurate estimation of wear resistance and coefficient of friction of the duplex-coated samples. All the results of the investigations indicated a significant influence of the white compound layer in governing the tribological and mechanical properties of the duplex-coated samples for as received as well as heat-treated samples.