Melt Processing and Properties of Barium‐Sialon Glasses

Abstract

Bulk oxynitride glasses in the system Ba‐Sialon were prepared by cooling homogenized melts from ∼1740°C at ∼50°C/min. The microchemistry, microstructure, and properties of these materials were studied by DTA, dilatometry, electron microscopy, and energy dispersive X‐ray analysis. Up to ∼ 7 at.% nitrogen was retained in the glasses by the conventional glass‐processing techniques used. Microscopically homogeneous glasses were obtained despite macroscopic segregation of millimeter‐sized metallic spheres consisting of Si and Fe. Incorporation of nitrogen in the glass network led to decreasing thermal expansion coefficients, higher glass‐transition temperatures, and greater values of indentation hardness with increasing nitrogen content.