Abstract

Fabrication of smooth damage-free diamond surfaces has been a popular subject in the manufacturing research field. In this study, the polycrystalline diamond was ground by a vitrified bonded diamond wheel to obtain damage-free diamond surfaces with low surface roughness and high quality. Atomic force microscopy verified that surface roughness of Sa 4.20 nm, Sa 2.06 nm, and Sa 0.548 nm were achieved under grinding speeds of 750, 1050, and 1350 rpm, respectively. Electron energy loss spectroscopy spectra confirmed the existence of a graphitic layer (black layer) with a thickness of similar to 15 nm in the subsurface after grinding. The "black layer " showed an easy ability to be removed under scratch and high-temperature oxidation. Moreover, transmission electron microscopy demonstrated that no damaged layer was observed in the subsurfaces at 750 rpm and 1050 rpm grinding speed. For grinding speed of 1350 rpm, stacking faults and micro-crack appear in the subsurface, thus forming a damaged layer with several microns in thickness. Our work proposes a new strategy to efficiently fabricate nanoscale smooth and damage-free diamond surfaces by diamond wheel grinding. More innovatively, this work demonstrates a unique removal mechanism for abrasive processing of hard-and-brittle materials, as distinct from either mechanical grinding or chemical mechanical grinding.