Experimental test to validate the rate equation “d α/d t = kf( α)” used in the kinetic analysis of solid state reactions

Abstract

In order to improve the soundness of the kinetic analysis of solid-state reactions, we present an experimental test based on a sudden change (jump), during an experiment, of the temperature, or of the partial pressure of gases, which have an influence on the kinetic rate. This test, denoted “ f( α) test” allows to discriminate if the kinetic modelling may or may not involve the rate equation d α/d t = kf( α) for any kind of reaction: thermal decomposition, solids reacting with gases, … Numerous examples are given and discussed according to the answer of the test, mainly based on the consideration of nucleation and growth processes.