Microstructure of 96% Alumina Ceramics: I, Characterization of the As‐Sintered Materials

Characterization of the microstructure and microchemistry of a group of commercial 96% Al 2 O 3 ceramics, using analytical and conventional electron microscopy techniques, was conducted. A continuous glassy grain‐boundary phase was found in all samples, in addition to a number of intragranular and intergranular crystalline second phases; the phases present depended on the original boundary‐glass composition. The faceted nature of many of the Al 2 O 3 ‐glass interfaces was studied and is thought to be an equilibrium structure.