Validity of isothermal kinetic prediction by advanced isoconversional method

Abstract

Isothermal prediction based on kinetic parameters from advanced isoconversional method (NLN) has been successfully used in various materials. However, the validity of the method is sometimes suspected because of some depressing predictions. In this paper, we set a single-step solid state reaction and a multi-step solid state reaction to simulate and predict. The effects of set temperature and composition of heating rate group on the isothermal prediction are evaluated. For the single-step reaction, all the relative errors of single-step reaction are less than 10%. Therefore, the method provides accurate enough isothermal predictions at different set temperatures and heating rate groups. As for the multi-step reaction, the accuracy of prediction varies with the set temperature and the composition of heating rate group. The reason for the failure of multi-step reaction prediction is the inconsistency in the concept of isothermal and nonisothermal isoconversional activation energy.