The relationship between intergranular segregation and grain boundary crystallography was investigated in the case of a Mg- and Ti-doped commercial-grade alumina. A marked enrichment of Ti, and of impurities such as Ca and Si, was found to occur at almost all of the grain boundaries. The well-ordered twin boundaries did not exhibit segregation, or grain boundaries whose plane was parallel to a dense plane of alumina in both grains. In grain boundaries with a high degree of segregation, the nature and content of the major element varied strongly with the grain boundary crystallographic parameters, and depended upon the orientation of the grain boundary plane. High-resolution electron microscopic studies of the grain boundary structure did not reveal the presence of any intergranular glassy phase in the material.

W.Swiatnicki, S.Lartigue-Korinek, J.Y.Laval: Acta Metallurgica et Materialia, 1995, 43[2], 795-805