The Preparation and Performance Analysis of a Cr2O3 Gel Abrasive Tool for Sapphire Substrate Polishing

Abstract

In order to solve the problem of the agglomeration of abrasives in traditional hot-pressing abrasive tools, this paper proposes a chromium oxide (Cr2O3) gel abrasive tool with a polyacrylamide gel and a polyimide resin as the bonding agent. The effects of the dispersant and slurry pH on slurry viscosity and the effects of different sintering temperatures on the properties of the abrasives tool were explored. The influence of abrasive tools on the friction coefficient at different sintering temperatures was compared through friction and wear experiments. A comparison experiment of sapphire substrate polishing was carried out to compare the processing effect of the hot-pressing abrasive tool and the gel abrasive tool on the workpiece. The experimental results show that, when the pH value of the slurry is between 8–9 and the mass fraction of the dispersant is 1.5 wt%, the viscosity of the slurry is the lowest. When the sintering temperature is 350 °C, the tensile and flexural strengths of the abrasive tool reach 96 MPa and 42 MPa, and the hardness reaches 72 HRF. In the friction wear test, the friction coefficient is the most stable, and the wear rate of the abrasive tool is the lowest. In the polishing experiment, the gel abrasive tool performs better than the hot-pressing abrasive tool. After processing using the gel abrasive tool, the average surface roughness Ra reaches 2.69 nm, and the flatness PV reaches 0.65 μm; after CMP, the surface roughness Ra reaches 0.67 nm and no scratches appear on the surface of the sapphire.