Thermal Decomposition of Brucite: I, Electron and Optical Microscope Studies

The decomposition of brucite was studied directly in electron and optical microscopes. A small amount of decomposition caused marked changes in the physical state of the brucite crystal. The decomposition was interpreted as a normal nucleation and growth process in which magnesium oxide nuclei formed coherently with the brucite matrix. This process accounts for: ( a ) the structural relations between parent and product phases, ( b ) the small crystallite size of the product, ( c ) the cracking process occurring in the initial stages of decomposition, and ( d ) the range of d spacings observed for the magnesium oxide formed during the decomposition.