The Investigation of Graphene Oxide-Enhanced Hybrid Slurry Preparation and Its Polishing Characteristic on CVD Single Crystal Diamond

As an environment-friendly material, graphene oxide nanosheet can effectively improve the polishing surface quality of single crystal diamond workpieces. However, the lubricating and chemical effects of graphene oxide nanosheets have an uncertain impact on the polishing material removal rate. In this paper, the graphene oxide-enhanced hybrid slurry was prepared with good stability. The femtosecond laser etching and contour measurement method was adopted to analyze the polishing material removal rate of the CVD single crystal diamond workpiece. The surface damage of the workpiece polished with SiC abrasive grains is minimal, while the workpiece with diamond abrasive grains has the largest material removal rate. With an increase in abrasive grain size, the polishing material removal rate increases, but new surface scratches and pits can be introduced if the grain size is too large. Therefore, a grain size of 2.5 μm was selected to improve the surface quality. The surface roughness first decreases and then increases with the increase in polishing rotation speed. At a speed of 4000 rpm, the surface roughness reached its minimum with a relatively high material removal rate simultaneously. A series of CVD single crystal diamond scratching experiments were conducted with different scratching speeds, which proved that graphene oxide can help facilitate material surface micro-protrusion removal.