Electrochemical magnetorheological finishing for hard-to-machine functional materials with nanometer-scaled surface roughness

Abstract

Tungsten carbide (WC) is a widely employed mold material in micro/nano-manufacture industry due to its exceptional attributes, including excellent chemical stability, high temperature resistance, and substantial stiffness. Nevertheless, its formidable hardness and wear resistance pose signi cant machining challenges. To realize high-quality and high-e ciency polishing, we introduce electrochemical magnetorheological nishing (ECMRF), which combins magnetorheological nishing (MRF) and electrochemical mechanical polishing (ECMP). Because the WC workpiece surface becomes loose rapidly due to the formation of an oxide layer through surface electrooxidation, ECMRF exhibits remarkable material removal rates (MRR) of up to 92.0 nm/min, nearly ve times higher than that of conventional MRF (16.7 nm/min). Moreover, ECMRF accelerates the convergence rate of surface roughness (Sa) by a factor of 17 when compared to MRF. More importantly, chemical composition analysis reveals no surface or subsurface chemical damage after an simple additional MRF process, maintaining the pristine state of the WC workpiece. The nal Sa is signi cantly reduced from 87.2 nm to 2.1 nm. This pioneering research underscores the prospect in polishing challenging materials and presents an innovative route to achieve highly e cient surface polishing with nanoscale roughness.