Pressure Dependences of the Melting Temperature of Graphite and the Electrical Resistivity of Liquid Carbon

Abstract

The melting line of graphite and the electrical resistivity of liquid carbon are investigated along the melting line by a flash-heating experiment under high pressures. The melting temperature of graphite increased from 4650 K at 1.4 GPa to a maximum of 4790 K at 5.6 GPa, then decreased to 4640 K at 9.4 GPa. The electrical resistivity of liquid carbon along the melting line decreased from 900 to $600\ensuremath{\mu}\ensuremath{\Omega}\mathrm{cm}$ with an increase of pressure of 1.4 to 9.4 GPa. Changes in slopes of the melting line and of the electrical resistivity at about 5.6 GPa suggest a possibility for a first-order phase transition in liquid carbon.