A New Method for Determining Material Thermal Properties at Static High Pressures

Abstract

The response of materials under shock loading is strongly dependent on the mechanical and thermal properties of materials at high pressures. Despite the availability of several methods that quantify mechanical properties of materials at high pressures and loading rates, only a few existing techniques can measure heat capacity or thermal conductivity at high pressures. A new method is proposed to determine the thermal transport properties of materials in gem anvil cells (GAC). The test material and a ruby sphere were enclosed in a GAC and brought to pressure. The ruby was heated at a constant rate by a pulse of light whose intensity had a square wave temporal profile. Time‐resolved ruby fluorescence spectra were recorded with a spectrometer and a streak camera. The temperature profile of the ruby during both the heating and cooling (following removal of the laser light) periods was sensitively dependent on the thermal transport properties of the surrounding material. A pressure‐dependent set of results is presented for sodium chloride (NaCl) and Teflon, utilizing this new technique. The data is compared to simulations using previously published data.