Enhanced electroless Ni-P plating quality on binderless tungsten carbide by atmospheric pressure plasma pretreatment

Abstract

Precision glass molding (PGM) has been widely utilized in optical components production, during which binderless tungsten carbide (WC) is a popular mold material. Researchers have proposed the application of electroless nickel‑phosphorus (NiP) plating on WC molds, offering good surface finish, non-stick properties, and enhanced corrosion resistance, while typical NiP plating pretreatment is complex, time-consuming, carrying risks of surface damage and pollution. In this study, Atmospheric-pressure (AP) plasma surface processing has been proposed as an alternative pretreatment technique to enhance electroless NiP plating quality on binderless WC, contributing to the reduction of plating steps, time, smoothing of the plated NiP layer, and improvement in adhesion quality. The interaction mechanism between AP plasma and WC has been analyzed. The influence of AP plasma surface pretreatment on the surface quality of NiP plating has been investigated in detail. Surface characterization and adhesion test have been conducted to evaluate the effectiveness of AP plasma pretreatment method. Despite the fact the replication of substrate roughness exists in typical NiP plating process, the surface roughening and enhanced surface energy induced by AP plasma pretreatment can have a smoothing effect for the following electroless NiP plating process. The effectiveness of ICP AP plasma as an alternative pretreatment technique for high-quality electroless NiP plating on binderless WC has been validated.