The goal of this research is to obtain a detailed understanding of indentation-induced flaw nucleation in ceramic materials. A unique high temperature microhardness tester, capable of operating up to 1600 0C, will be used to produce indentations. Indentation sites will be characterized by SEM and TEM in order to determine effect of crystallography, load, and temperature on the deformation mechanisms leading flaw nucleation. Initially, single crystals of alumina, magnesium oxide, and barium titanate will be used, followed by bicrystals.