Density, Thermal Expansion, Enthalpy, Heat Capacity, and Thermal Conductivity of Calcium in the Temperature Range 720-1290 K

Thermophysical properties of solid and liquid calcium (99.75 wt % pure) were experimentally studied with high accuracy in the temperature range 720-1290 K using dilatometer measurements, gamma-ray attenuation measurements (the gamma-ray method), high-temperature drop calorimetry, and the laser flash method. The behaviors of the density, enthalpy, and thermal conductivity of calcium in the fusion-crystallization region were studied. The enthalpy of fusion was measured as 8075 J/mol, the relative density change upon fusion as 3.3%, and the relative change in thermal conductivity upon fusion as 26%. The results were compared to the respective values in the related literature. The measurements at temperatures above 720 K either significantly amend the available literature data, or are currently unique. The constancy of the heat capacity of liquid calcium in the temperature range 1115-1290 K was verified. Fitting equations were derived, and recommended values of the investigated properties of calcium were tabulated for 720-1290 K, the temperature range where calcium is in the condensed state.