Synthesis and High-Temperature Heat Capacity of Neodymium Titanate

Neodymium dititanate, Nd2Ti2O7 (monoclinic structure, sp. gr. P21), has been prepared by solid-state reaction in air at temperatures from 1673 to 1773 K using the Nd2O3 and TiO2 oxides as starting materials. The high-temperature heat capacity of the resultant polycrystalline Nd2Ti2O7 samples has been determined by differential scanning calorimetry. The experimental Cp(T) data have been used to evaluate the thermodynamic functions of neodymium dititanate (enthalpy increment H°(T)–H°(320 K), entropy change S°(T)–S°(320 K), and reduced Gibbs energy Ф°(T)) in the temperature range 320–1053 K.