Study on the polishing mechanism under the combined effect of K2CO3, KH550 and ultrasonic vibration for K9 optical glass

Abstract

K9 optical glass plays an important role in the field of optics and optoelectronic information due to its high thermal stability and excellent optical imaging properties. Considering the low polishing efficiency and surface quality from its extremely high hard and brittle properties, a novel SiO₂ polishing slurry containing K₂CO₃ and 3-aminopropyltriethoxysilane (C₉H₂₃NO₃Si, KH550) is prepared for ultrasonic vibration chemical–mechanical polishing (UV-CMP) of K9 optical glass, and its polishing characteristics and mechanism are investigated. The results demonstrate that K₂CO₃ promotes the material removal rate (MRR) significantly, while the adsorption effect of KH550 reduces the wear ratio and coefficient of friction (COF), and improves the dispersion of SiO₂ abrasive particles and polishing performance of UV-CMP remarkably. Ultrasonic wave further induces softening of surface hydration reaction, homogeneous distribution of abrasive particles and enhances impact and grinding ability of abrasive particles. The optimal MRR is14.5298 μm/min and Sa is 54.07 nm at 1.5 wt% K₂CO₃, 1.6 wt% KH550 and the ultrasonic amplitude of 6 μm, indicating that the UV-CMP supplied guidance for multi-field-assisted polishing of hard and brittle materials.