Thermodynamic and Thermochemical Characteristics of Erbium Silicides

Abstract

The Gibbs energies and enthalpy and entropy of formation of erbium silicides ErSi_2–b (ErSi_1,67), ErSi, ErSi_1–х(ErSi_0,96), Er₅Si₄ and Er₅Si₃ are determined by measuring of electromotive forces in the range 820–1050 K. The enthalpy of ErSi1,67, ErSi, and Er5Si3 in the wide temperature range is studied by the drop calorimetry method. The temperature dependences of the heat capacity, entropy, and reduced Gibbs energy of these compounds are determined from the experimental data. The enthalpies and entropies of polymorphic transformation β-ErSi_2–b ↔ α-ErSi_2–b and the melting enthalpy and entropy of ErSi_2–b5Si₃ silicides are also determined.