Product crystallite size–reaction rate relationship in M(OH)2–MO decomposition. Structural transformation mechanism

Abstract

Two mechanisms were proposed to explain the decomposition reaction of brucite: the homogeneous and the inhomogeneous mechanisms. These two mechanisms, on the one hand, and the main structural transformation modes, on the other, are reviewed and discussed in connection with an important new result. When no sintering occurs the oxide crystallite size is independent of temperature, i.e. it is independent of the overall reaction rate. This result excludes a diffusion process and is in agreement with the homogeneous mechanism. It is shown that the structural transformation associated with this reaction exhibits the most important morphological and structural features of a shear transformation.