Enhancement mechanism of Y-doped Ce1−xYxO2 for photocatalytic-assisted chemical-mechanical polishing

Photocatalytic-assisted chemical-mechanical polishing (PCMP) is an ultra-precision machining method which combines photocatalytic technology with chemical-mechanical polishing (CMP) technology. CeO2 has unique physicochemical properties (tribological properties and photochemical oxidation activity) and is applied to industrial fields extensively. In this paper, a series of Ce1−xYxO2 nanoparticles with controlled size and shape were produced by the molten salt method. SEM images show that Ce1−xYxO2 nanoparticles are nearly spherical with a size of about 113–148 nm. Ion doping can adjust the defect concentration and further enhance the chemical activity of samples. XPS spectra show that doping is beneficial to improve the concentration of Ce3+ and oxygen vacancy. In this way, the photocatalytic activity of CeO2 nanoparticles can be improved. Quartz glasses were polished by synthetic Ce1−xYxO2 nanoparticle polishing solution, where x is the doping amount. The results show that the material removal rate (MRR) of Ce0.95Y0.05O2 abrasives in PCMP was increased by 34.5%. The PCMP mechanism of CeO2 nanoparticles is further discussed. Ultraviolet irradiation increased the reactive sites on the surface of Ce1−xYxO2 nanoparticles, making them have better chemical activity. The hydration layer and Ce-O-Si bond on the surface of quartz glass are formed more easily, thus improving the material removal rate.