Impact of the gaseous environment on the kinetics of solid-state decompositions

The main purpose of this study is to review the current state of the problem of the impact of gaseous environment on the kinetics of solid-state decompositions. Three different theoretical approaches to the interpretation of the decomposition kinetics have been considered. As it follows from the literature published over the past 80 years, the Arrhenius and Knudsen-Langmuir approaches based on the assumption of two different reaction mechanisms (congruent and incongruent) could not solve the problem. At the same time, successes in the application of the thermochemical approach that is based on the assumption of a unitary congruent dissociative vaporization mechanism with condensation of oversaturated vapor remain unnoticed by the TA community. Taking into account this situation, the author has outlined the key points of the thermochemical kinetics in a compact but rigorous and complete form once more. The revised kinetic equations for the different modes of decomposition, several important interrelations between the kinetic parameters, and, finally, the results in the interpretation or reappraisal of the main effects related to the impact of gaseous environment on the kinetics have been considered. In the framework of the thermochemical approach, the problem being discussed may be considered nowadays practically resolved.