TRANSFORMATION OF C-60 FULLERENES INTO A SUPERHARD FORM OF CARBON AT MODERATE PRESSURE

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-1cm-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.© 1995 American Institute of Physics.