DIAMOND PRODUCTION AS A RESULT OF ELECTRICAL EXPLOSIONS OF GRAPHITE-CONTAINING SAMPLES

A method to achieve the region of thermodynamic stability of diamond i s described. Pressures in the range 10-30 GPa and temperatures in the range 2000-4000 K may be obtained by current pulse heating of a specia l graphite-containing sample. Numerical modeling of some regimes of ca pacitor bank discharge through the sample showed that this is possible by current pulses with a duration 2-10 mus and a magnitude of about 1 MA and higher. In doing so, the conductivity of the sample is of grea t importance. The analysis of numerical modeling results indicates tha t the best values of diamond synthesis parameters are achieved for met allic samples. Nonporous material containing small graphite particles having a size in the range of 10-100 mum was used. The best results ar e achieved when graphite constitutes no more than about 30% by volume of the sample. The method was tested under laboratory conditions. In t hese experiments, hexagonal diamond particles were obtained. The mean size of diamond crystallites was about 0.1-0.2 mum or smaller.