Melting Curves of Copper, Silver, Gold, and Platinum to 70 kbar

Abstract

The melting curves of Cu, Ag, Au, and Pt have been measured versus pressure to 60 or 70 kbar using the discontinuity in electrical resistance of a wire enclosed in parallel heating strips. The results, which compare favorably with other measurements at lower pressures, were fit to a Simon's equation. Only in the case of gold do the measured parameters in this equation closely agree with that predicted theoretically. Pressure corrections to the thermocouple measurement and temperature corrections on the pressure calibration are considered. The melting curves for Au and Ag and probably Pt are normal in the sense that they curve toward the pressure axis, but the melting curve for Cu is linear over the pressure range measured to within the accuracy of the experiment.