Transformation of C60 fullerenes into a superhard form of carbon at moderate pressure

Abstract

A very hard and conducting form of carbon has been obtained from pure C60 fullerenes, as well as its mixture with aluminium at nonhydrostatic pressures of 2.6–3 GPa and a temperature of 700 °C. The hardness of the material is more than 4000 kg/mm2. Its electrical conductivity is about 100 Ω−1 cm−1 and is weakly dependent on temperature in the range 4.2–300 K. X-ray diffraction and Raman measurements show lack of the long-range crystalline order in the transformed material.