Composition‐dependent thermal and thermomechanical properties of spinel‐type MgAlON from density functional calculation

Abstract

AbstractAs ceramics based on magnesium aluminum oxynitrides solid solutions are promising materials as refractories, windows/armors, phosphors, and so forth, it is essential to explore their thermal and thermomechanical properties, owing to the physical requirements on application. In this study, Mg5xAl23−5xO27+5xN5−5x were chosen for the investigation on composition‐dependent thermal and thermomechanical properties by the theoretical calculations. Though the binary system with octahedral bonds contributes more to the thermal expansion coefficient of Mg5xAl23−5xO27+5xN5−5x, the binary system with tetrahedral bonds plays an important role in the variation of the thermal expansion coefficient. The change of heat capacity with the rise of x is mainly attributed to the variation of covalent character of Mg5xAl23−5xO27+5xN5−5x. Moreover, the thermal conductivity is mainly affected by the scattering from atoms in 8a sites. Both thermal and mechanical properties contribute to the variation of thermomechanical properties of Mg5xAl23−5xO27+5xN5−5x. This study can provide guidance to designing spinel materials with desirable thermal and thermomechanical properties for application.