Structures and physical properties of superhard and ultrahard 3D polymerized fullerites created from solid C60 by high pressure high temperature treatment Original Research Article

Superhard and ultrahard phases of C60 were synthesized by quenching at high pressures up to 13 GPa and high temperatures in the 300–2100 K range. The structures of the samples are discussed on the basis of X-ray and Raman spectra and electron microscopy data. The following physical properties of hard samples were studied: specific gravity; specific heat in the range 400–600 K; sound velocities; elastic moduli; electrical properties; resistance to uniaxial stress; stability against oxidation. These properties are different from those of diamond and other carbon forms. The hardness of ultrahard fullerites exceeds the hardness of diamond.