Covalently armoring graphene on diamond abrasives with unprecedented wear resistance and abrasive performance

Abstract

Next-generation semiconductor materials, including diamond, SiC, and GaN, offer significant advantages for high-power devices. However, the high-performance polishing of these ultrahard materials is limited by insufficient grit wear resistance and low-quality material removal with conventional diamond abrasives. In this study, we report robust integration of flexible graphene armor on diamond abrasives through covalent interfacial bonding for high-efficiency high-quality polishing of ultrahard materials. Utilizing a novel Ga-diamond cellular wetting strategy followed by vacuum heating treatment, we achieved highly scalable production of graphene-armored diamond abrasives with a productivity of 1 kg/L. The employment of graphene-armored diamond abrasives simultaneously improved the polishing efficiency and polishing quality, enabling damage-free atomic-level surface finish and an atomic attrition rate 5 times greater than conventional diamond abrasives. This efficient material attrition is attributed to the robust combination of exceptional intrinsic wear resistance, bonding capability and high flexibility of graphene with the ultrahigh hardness of diamond. The synergy of soft graphene and hard diamond grit provides sufficient material removal capability while simultaneously reducing the polishing damage that is often induced by brittle fracture and extreme local contact pressure with conventional diamond abrasives. This work offers a novel solution that enables high-efficiency high-quality polishing of ultrahard materials with a room-temperature, chemical-free and low-cost mechanical polishing procedure.