Pulse calorimetry and transient measurement of thermal properties at high temperatures

Abstract

A system is described for the transient (subsecond) measurement of selected thermal and related properties of electrically-conducting substances in the temperature range 1500 K to the melting point of the specimen. The method is based on resistive self-heating of the specimen from room temperature to any desired high temperature in less than 1 s by the passage of an electrical current pulse through it; and on measuring and recording the experimental quantitites every 0.4 ms with a full-scale signal resolution of one part in 8000. The system has been used to measure heat capacity, electrical resistivity, hemispherical total emittance, normal spectral emittance, and the melting point of selected refractory elements and alloys. The results of preliminary experiments have shown the potential application of the system to measurements of temperatures and energies of solid–solid phase transformations and heat of fusion at high temperatures.