Specific heat and thermodynamic properties of undercooled liquid cobalt

Co is undercooled to 227 K (0.128 T_m) and its specific heat has been determined as 40.6 Jmol^-1K^-1 by electromagnetic levitation drop calorimeter, whose good accuracy is verified by the measured specific heat data of pure nickel. On the basis of measured specific heat data, the thermodynamic properties, such as thermodynamic driving force and relative nucleation rate, are calculated. Moreover, the theoretical models of Turnbull and Dubey-Ramachandrarao are also used to calculate the thermodynamic properties for a comparison. It is found that both the thermodynamic driving force and relative nucleation rate have large deviation compared with the calculated results based on experimental data. This indicates that, since the deviation of specific heat value has a drastic influence on thermodynamic driving force and nucleation rate for the undercooled liquid metals, it is necessary to measure the specific heat quantitatively by experiments.