Structures and physical properties of superhard and ultrahard 3D polymerized fullerites created from solid C 60 by high pressure high temperature treatment

Abstract

Superhard and ultrahard phases of C 60 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.