Barium Gallogermanate Glass Ceramics for Infrared Applications

The germanate glass ceramics is a potential candidate material for infrared (IR) dome and window applications. The crystallization mechanism of 20BaO-10Ga2O3-70GeO2 glass was investigated by differential thermal analysis (DTA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Two different types of phase evolution were found in the early stage of crystallization: (1) the further growth of the microcrystal formed during the slow cooling of glass melt and (2) the glass-in-glass phase separation. The controlled crystallization was obtained by two-step heat treatment. The middle infrared (MIR)-transparent glass ceramics were obtained, with expected thermal and mechanical improvements.