Published online by Cambridge University Press: 28 February 2011
The present understanding of the structure of grain boundaries and phase boundaries in ceramic materials is briefly reviewed with a view to extracting general conclusions on the structure of such interfaces. Examples of experimental studies of grain boundaries in alpha-alumina, spinel and germanium are discussed together with illustrations of the wustite/spinel and sesquioxide/spinel interface. In the oxide systems discussed here, both the grain boundaries and phase boundaries can facet even in the case where the anion sublattice is effectively undisturbed, this observation emphasises the influence of the cations on the selection of the boundary plane.