Study on process parameters of ultraviolet photocatalytic-Fenton reaction polishing of single-crystal silicon carbide based on Ag@AgCl photocatalyst

To address the issues of low photocatalytic activity, poor stability, and insufficient reusability of traditional photocatalyst TiO₂, a novel Ag@AgCl photocatalyst was prepared in the early stage. Under ultraviolet (UV) irradiation, the photocatalyst utilises the characteristics of photogenerated carrier separation and surface plasmon resonance effect to efficiently generate highly oxidative hydroxyl radicals, thereby significantly enhancing the photocatalytic performance, accelerating the oxidation process of single-crystal silicon carbide (SiC), and achieving its high-efficiency and high-quality processing. In this study, this novel photocatalyst was applied to the UV photocatalytic-Fenton reaction polishing of single-crystal SiC, with a focus on exploring the effects of major polishing process parameters on the surface quality and material removal rate (MRR) of single-crystal SiC. A set of polishing process parameters with high MRR and surface quality requirements were obtained. The influence of abrasive types on the surface quality and MRR of single-crystal SiC was studied by single factor experiment method, and a reasonable orthogonal optimization experiment was designed to seek better polishing process parameters. The research results indicate that the use of diamond abrasive can effectively improve the polishing effect in the UV photocatalytic-Fenton reaction polishing process of single-crystal SiC. Under the conditions of polishing pressure of 50 kPa, polishing speed of 60 rpm, diamond particle size of 200 nm, concentration of 2 wt%, H₂O₂ concentration of 5 wt%, and photocatalyst concentration of 1.8 wt%, excellent polishing effect with MRR of 1757.6 nm/h and surface roughness Ra of 0.45 nm was achieved. The UV photocatalytic-Fenton polishing technology, which is based on the Ag@AgCl photocatalyst and optimized process parameters, can achieve a high MRR while also obtaining a high-quality single-crystal SiC surface.