Advances and problems in the investigation of the mechanisms of solid-state reactions by analysis of absolute reaction rates

Some preliminary results of application of the dissociative-evaporation scheme and of the method for calculation of the absolute reaction rates to an analysis of the kinetics and interpretation of the mechanism of solid-state reactions are presented. This analysis is based on the literature data obtained by methods of classical thermal analysis. A discussion is given of some general features of solid-state reactions, which are connected with the primary products of decomposition being different from the equilibrium composition, and with the effects of the external partial pressure of gaseous products and the reactant self-cooling on the decomposition kinetics. These features are taken into account in a consideration of the decomposition mechanism of some important classes of inorganic compounds, namely, salt hydrates, hydroxides, azides and carbonates. The problems associated with the effect of condensation of a low-volatility product on the rate of reactant decomposition and, as a consequence, on the origin of induction and acceleratory periods during the decomposition process are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.