Structural transformations during sintering and annealing of beta alumina

Changes in the phase content, microstructure, and lattice parameters occur in stabilized beta / beta double prime -Al sub 2 O sub 3 specimens following extended sintering and annealing treatments. Following post-sinter heat treatment, splitting of XRD peaks reveals a segregation of the beta double prime -phase into 2 components of differing lattice parameter. The splitting is attributed to a structural change resulting from the expulsion of Na sub 2 O from supersaturated beta double prime -grains.