Electron microscopic study of the dehydration of diaspore

The thermal transformation of natural, single-crystal diaspore (D) to corundum (C) and water has been analyzed in detail by means of transmission electron microscopy (TEM). Pieces of singlecrystal diaspore were partially dehydrated at temperatures ranging from 400 to 600 °C and were prepared in cross-section for TEM studies. The transformation of diaspore was studied at the faces (100)D, (010)D, and (001)D, with special attention to the microstructural details at the reaction interface.