Scratching tests of a diamond substrate were performed using a tool fixed with four types of grains potentially harder than diamond. Materials reported by other researchers to be harder than diamonds often contain combinations of carbon, boron, and nitrogen. From the viewpoint of manufacturing, fullerene, wurtzite (hexagonal lattice boron nitride), polycrystalline diamond, and flame-synthesized diamond were selected in this study. After creating and testing saw wires and wheel saws, flame combustion synthetic diamond was determined to be the most promising. This is because only scratches from flame combustionsynthesized diamond initiate cleavage fracture.
MIZUMA et al. (Thu,) studied this question.