Synthesis and Thermodynamic Functions of Erbium Titanate at 2–1900 K

Abstract

Erbium titanate was synthesized by the coprecipitation of erbium and titanium hydroxides followed by high-temperature annealing. The temperature intervals of the formation sequence of the pyrochlore-type crystal structure were determined. The isobaric heat capacity of erbium titanate in the range 2–1870 K was measured by relaxation calorimetry, adiabatic calorimetry, and differential scanning calorimetry. The smoothed heat capacity values were used to calculate the entropy and enthalpy increment in the range 0–1900 K, evaluate the contribution of the Schottky anomaly at temperatures up to 300 K, and calculate the Gibbs free energy of erbium titanate formation at 298.15 K.