Melting line and thermal equation of state of fcc-cobalt: A combined experimental and computational approach
Simone Anzellini, Silvia Boccato, Samuel Baty, Leonid Burakovsky, Daniele Antonangeli, Daniel Errandonea, R. Torchio
Abstract
The melting line of cobalt has been investigated both experimentally, using synchrotron X-ray diffraction coupled with laser-heated diamond anvil cells, and theoretically, using ab initio simulations. Over the investigated pressure and temperature range - between 30 and 100 GPa and from ambient temperature up to 4000 K - the hexagonal close-packed structure, stable at ambient conditions, is replaced at high temperature by the face-centred cubic structure, observed stable till melting. The melting temperatures obtained by the two methods are in remarkable agreement and the melting line can be well described by a Simon-Glatzel equation of the form Tm = 1768(K)(P(GPa)/35.62+1)0.64. Finally, from the obtained results it was possible to determine a thermal equation of state for the cubic face-centred phase of Co.