Thermal expansion and heat capacity of dysprosium hafnate

Dysprosium hafnate is a candidate material for as control rods in nuclear reactor because dysprosium (Dy) and hafnium (Hf) have very high absorption cross-sections for neutrons. Dysprosium hafnate (Dy2O3 center dot 2HfO(2)-fluorite phase solid solution) was prepared by solid-state as well as wet chemical routes. The fluorite phase of the compound was characterized by using X-ray diffraction (XRD). Thermal expansion characteristics were studied using high temperature X-ray diffraction (HTXRD) in the temperature range 298-1973 K. Heat capacity measurements of dysprosium hafnate were carried out using differential scanning calorimetry (DSC) in the temperature range 298-800 K. The room temperature lattice parameter and the coefficient of thermal expansion are 0.5194 nm and 7.69 x 10(-6) K-1, respectively. The heat capacity value at 298 K is 232 J mol(-1) K-1.