Thermal expansion and thermodynamic properties of M′-YbTaO4 ceramics

Abstract

The synthesis of M′-YbTaO4 ceramics was carried out by co-precipitation and calcination at 1700 K; phase and chemical purity were confirmed by XDA, XPS, and chemical analysis.The thermal expansion of the crystal lattice was determined by high-temperature diffraction analysis, and the linear and volume thermal expansion coefficients of M′-YbTaO4 ceramics were calculated at 298–1173 K. The heat capacity of M′-YbTaO4 ceramics was measured using adiabatic methods in the temperature range of 19.6–350 K and differential scanning calorimetry in the range of 316–1326 K. Using the smoothed heat capacity values, the thermodynamic functions of entropy, changes in enthalpy, and reduced Gibbs energy of M′-ytterbium orthotantalate were calculated. The Schottky-type anomalous contribution in the temperature dependence of heat capacity was estimated.