The free surfaces of ceramic materials control many of the important properties of these materials including, for example, their sinterability and catalytic activity. Ceramic surfaces are currently the subject of a range of theoretical and experimental treatments. This study is part of a broader program which monitors ceramic surfaces under experimental conditions which more closely parallel those encountered during the commercial processing of ceramic materials than the conditions utilized in conventional surface-sensitive UHV techniques. TEM foils of single crystal α-Al2O3 were prepared in the usual way and annealed in air for 24h at 1400°C . The microstructure which typically results from this heat treatment is shown in Fig.1A, a bright-field (BF) image from a (1120) α-Al2O3 foil with the electron beam parallel to the [1120] direction.