Using high-resolution electron microscopy, temperature dependence of faceting of an asymmetric Σ5 grain boundary in SrTiO3 was observed. The bicrystal samples were fabricated by ultra-high vacuum diffusion bonding and heat-treated between 1100 and 1600C. Below 1300C, this grain boundary facets into symmetric (310) and asymmetrical (100)//(430) grain boundary planes. At 1300C, in addition to the asymmetric facet, the symmetric {210} facet appeared: three different facets were thus observed at this temperature. At 1400 and 1500C, the asymmetrical facet disappeared and the two kinds of symmetrical facets remain. At 1600C, faceting disappeared and the grain boundary became de-faceted. The faceting/de-faceting transition behavior of the grain boundary was interpreted in terms of the Wulff plot and its corresponding equilibrium crystal shape.

Temperature Dependence of Faceting in Σ5 (310) [001] Grain Boundary of SrTiO3. S.B.Lee, W.Sigle, W.Kurtz, M.Rühle: Acta Materialia, 2003, 51[4], 975-81