A novel approach to obtain near damage-free surface/subsurface in machining of single crystal 4H-SiC substrate using pure metal mediated friction

High speed friction induced removal behavior of single crystal silicon carbide (4H-SiC) by pure metals (iron and nickel) were investigated, and the subsurface damage were explored for both C-face and Si-face of SiC substrates. A near damage-free subsurface was obtained for C-face SiC substrate. Crystal defects including cracks, dislocations, stacking faults and lattice distortions were evidenced for Si-face SiC substrate. The highest material removal rate (MRR) was found to be 8.9 μm/min on Si-face using pure nickel. The formation of silicide and/or oxide indicated that the material removal of C-face and Si-face of 4H-SiC were both dominated by the friction-induced chemical interaction. A friction reaction-removal model of single crystal 4H-SiC substrate using pure metal was also proposed in this paper.