First-Principles Thermochemistry and Thermodynamic Modeling of the Al2O3-Nd2O3-SiO2-Y2O3 Pseudoquaternary System

Abstract

The Al2O3–Nd2O3–SiO2–Y2O3 pseudoquaternary system was thermodynamically modeled with a focus on the phase equilibria concerning the sintering of neodymium-doped yttrium aluminum garnet, Nd:YAG ((Y1−xNdx)3Al5O12). The Nd2O3–SiO2 and Nd2O3–Y2O3 systems were evaluated. Due to the lack of experimental thermochemical data, first-principles calculations were used to predict the enthalpy of formation of Nd2SiO5 and the enthalpy of mixing of Nd in YAG. Isothermal sections of the Al2O3–Nd2O3–SiO2, Al2O3–Nd2O3–Y2O3, and Nd2O3–SiO2–Y2O3 pseudoternary systems are presented.