Corrosion and wear performance of Si face of single-crystal SiC based on metal electrochemical corrosion

Abstract

Abstract Herein, we proposed a chemical mechanical polishing method for single-crystal SiC based on metal electrochemical corrosion and investigated the corrosion and wear performance of the Si face of single-crystal SiC. By comparing the corrosion performance of Al, Cu, and Fe metals on the Si face in a Na2SO4 electrolyte solution, it was found that only Al can generate a noticeable corrosion layer. The EDS and XPS analyses of the Si face confirmed that the corrosion is due to the formation of the SiO2 layer. Frictional wear experiments were conducted to investigate the influence of solution composition on the wear behavior of Si face. Increasing the concentration of the Na2SO4 electrolyte solution resulted in higher wear, with a maximum wear value of 7.19 µm2 obtained in 1 mol/L Na2SO4 electrolyte solution. In an acidic corrosive solution, the Si face exhibited the highest material removal, with a wear value of 11.97 µm2 achieved at pH 3. The material removal mechanism of single-crystal SiC via metal electrochemical corrosion involved the corrosive reaction involving Al at the cathode, which generated a corrosion current, and the subsequent oxidation of the SiC surface at the anode, forming a SiO2 oxide layer leading to material removal.