Nucleation and Growth of Cubic Diamond in Shock Wave Experiments

Abstract

In 1959 the announcement that the presence of diamond had been detected in a sample of shock-compressed graphite was met with skepticism; it was pointed out that the calculated shock temperature was much too low to permit nucleation and growth of diamond during the microsecond available at pressure. Jamieson subsequently confirmed the presence of diamond and suggested a diffusionless mechanism, c-axis compression of rhombohedral graphite [1]. However, subsequent experiments yielded diamond far in excess of the amount of rhombohedral graphite present in the initial material. Furthermore, when shock temperature and shock pressure were varied independently, yields of diamond were found to depend more strongly on calculated shock temperature than on shock pressure, over the shock pressure range from 15 to 150 GPa. The calculated shock temperatures associated with good diamond yields were only about 1500 C, too low for nucleation and growth to be plausible.