Ultrahard and superhard phases of fullerite C60: Comparison with diamond on hardness and wear

Abstract Hardness and wear of ultra-and superhard fullerites and diamond were measured. The measured hardness was revealed 137±6 and 167±5 GPa for the diamond faces (100) and (111) respectively and that for the ultrahard fullerites was 290±30 and 310±40 GPa depending on synthesis conditions. The method of sclerometry (scratch at a constant indenter load) was used for the hardness measurements. The diamond surface (111) was deformed as a plastic material under the scratching with the ultrahard fullerite C60 indenter at room temperature. A wear resistance of ultrahard fullerite ceramic in order exceeds that of polycrystal (carbonado-type) diamond. The results of hardness and wear measurements of ultra- and superhard fullerites show a good opportunity for processing of hard and superhard materials.