Specific heat of refractory carbides (ZrC_0.95, HfC_0.85 and Ta_0.8Hf_0.2C) in the temperature interval 2500-5000 K

Abstract

A fast method for studying the physical properties of substances is considered, -heating by a single current pulse for 5-8 µs. Its advantages over the stationary methods is in obtaining bulk thermophysical properties of carbides at high temperatures (2500-5000 K). The temperature was measured by an optical method using high-speed photo-detectors PDA-10A (Thorlabs) and temperature lamp calibration. There is a sharp increase in the heat capacity of the solid phase for « 300 K before melting for all the studied carbides. It is assumed that the reason for the accelerated growth of heat capacity is associated with the formation of paired Frankel defects, in conditions of insufficient time for saturation of the volume with equilibrium vacancies.