Diamond-Graphite Equilibrium Line from Growth and Graphitization of Diamond

Diamond growth occurs at high temperatures and pressures in the presence of certain molten metals which serve as solvent catalysts. The zones of pressure and temperature in which diamond growth occurs have been determined for a number of metals. These zones are bounded on the low-temperature side by the melting point of the metal-carbon eutectic at pressure. They are bounded on the high-temperature side by the diamond-graphite equilibrium line. This experimentally determined equilibrium line agrees very closely with the theoretical extrapolation of the thermodynamically calculated line proposed by Berman and Simon, viz., P(kbar)=7.1+0.027T(∘K).