First‐Principles Thermochemistry and Thermodynamic Modeling of the Al ₂ O ₃ –Nd ₂ O ₃ –SiO ₂ –Y ₂ O ₃ Pseudoquaternary System

Abstract

The Al 2 O 3 –Nd 2 O 3 –SiO 2 –Y 2 O 3 pseudoquaternary system was thermodynamically modeled with a focus on the phase equilibria concerning the sintering of neodymium‐doped yttrium aluminum garnet, Nd:YAG ((Y 1− x Nd x ) 3 Al 5 O 12 ). The Nd 2 O 3 –SiO 2 and Nd 2 O 3 –Y 2 O 3 systems were evaluated. Due to the lack of experimental thermochemical data, first‐principles calculations were used to predict the enthalpy of formation of Nd 2 SiO 5 and the enthalpy of mixing of Nd in YAG. Isothermal sections of the Al 2 O 3 –Nd 2 O 3 –SiO 2 , Al 2 O 3 –Nd 2 O 3 –Y 2 O 3 , and Nd 2 O 3 –SiO 2 –Y 2 O 3 pseudoternary systems are presented.