Dislocation Etch Pits in Single-Crystal and Poly crystalline Beryllium Oxide

An etching solution is reported which can successfully reveal dislocation sites on the basal, first- and second-order prismatic, and the first-order pyramidal planes of beryllium oxide single crystals. Each of these crystallographic surfaces has an uniquely shaped dislocation etch pit which had not previously been reported. Freshly introduced dislocations on all the above planes were mobile at room temperature under high stresses. Dislocation motion was observed in several directions having low indices. The etchant also revealed dislocation sites in as-sintered and plastically deformed polycrystalline specimens.