Thermal diffusivity and thermal conductivity studies on europium, gadolinium and lanthanum pyrohafnates

Abstract

The measurement of thermal properties forms an important aspect of the research on materials of interest in nuclear technology. In particular thermal diffusivity and thermal conductivity data are of relevance in the quantitative evaluation of the heat flow and temperature variations in materials operating at high temperatures. Since isotopes of several lanthanide elements and hafnium have high neutron absorption cross-sections, their compounds are potential candidates for control rod applications. In this paper, our studies on rare earth pyrohafnates R₂Hf₂O₇ (where R represents a rare earth), which are 2:1 solid solutions of hafnium dioxide and a rare earth sesquioxide, are reported. Thermal diffusivity and thermal conductivity data obtained on europium, gadolinium and lanthanum pyrohafnates, employing a laser flash apparatus set up in our laboratory and covering the temperature range 600-1300 K, are presented.