Grain-Boundary Microstructures in a Liquid-Phase Sintered Alumina ( Alpha -Al sub 2 O sub 3 )

摘要

Grain boundary microstructures in a commercial 99.8% alumina ceramic have been analyzed using transmission electron microscopy. Nearly all boundaries are wet by an amorphous film, therefore, the CSL and DSC lattice construction should be invalidated. Facets of widely differing sizes are observed primarily on basal (0001), rhombohedral (anti 1012), and prism (11 anti 20) planes. The facets are always multiatomic in height and range up to approx. 1000A; this probably results from substantial anisotropy in the Al sub 2 O sub 3 -glass interfacial energy. Basal annealing twins are observed without amorphous films; they lie predominantly on (11 anti 20) and show interfacial energies much lower than adjacent random boundaries. (ERA citation 07:054438)