Fusion Curves of Four Group VIII Metals to 100 000 Atmospheres

The fusion curves of Ni, Pt, Rh, and Fe have been experimentally determined to 100 000 atmospheres. At this pressure, the melting points of the pure metals were: Ni, 1670±10°C; Pt, 2070±15°; Rh, 2400±15°; Fe, 1740±10°. The Pt and Rh values were extrapolated by Simon's fusion equation which fitted all of the data quite well and enabled the volume changes at the mp to be computed. $\frac{\Delta V}{V_s}$ for the four metals were: Ni, 0.06±0.01; Rh, 0.12±0.03; Fe, 0.03±0.005. The constants of Simon's equation differed considerably from their theoretical values but a functional relationship appears evident between Simon's exponent $c$ and the Grüneisen constant $\gamma$.