STUDY OF INTERGRANULAR PHASE IN ALUMINA CERAMICS

Metal-ceramic seals have in recent years become widely used in high Va cuum technology. One of the ceramics used in these seals is high alumi na. High alumina ceramics with additives from the system CaO-MgO-SiO2 were investigated by SEM. Reactions of the alumina with these additive s result in the formation of a liquid phase at the firing temperature. At room temperature this phase is a separate part of the microstructu re. Studies of the microstructure by SEM show the inhomogeneity of the intergranular phase. Many areas with different chemical compositions were found. The intergranular phase was analysed by EDS.