High Pressure Synthesis of Diamond in the Systems of Grahpite-Sulfate and Graphite-Hydroxide

Abstract

Diamonds were reproducively synthesized from graphite in the presence of Na2SO4, MgSO4, CaSO4·1/2H2O, Mg(OH)2 and Ca(OH)2 at high pressure of 7.7 GPa and a temperature of 2150°C. Although starting graphite was completely transformed to diamond in the presence of the sulfates or hydroxides, no transformation to diamond could be detected from graphite only at the same pressure and temperature condition. Therefore, we concluded that sulfates and hydroxides have a strong catalytic effect on the transformation of graphite to diamond.