Kinetic analysis of solid-state reactions: Precision of the activation energy obtained from one type of integral methods without neglecting the low temperature end of the temperature integral

Many approximated equations have been proposed to approximate the temperature integral, which frequently occurs in the nonisothermal kinetic analysis of solid-state reactions and has no exact analytical solution. The main application of those equations is the determination of the activation energy, not the estimation of the temperature integral. Several authors have analyzed the precision of the activation energy obtained from some integral methods. In their calculations, the low temperature end of the temperature integral was neglected. In this paper, a systematic analysis of the precision of one type of integral methods for the determination of the activation energy has been carried out without doing any simplification. Our results have indicated that for all integral methods analyzed in this work, there is a significant influence of two dimensionless quantities (γ, the dimensionless activation energy, and ξ, the normalized temperature) in the precision of the calculated activation energy values.

The relative error involved in the activation energy obtained from one type of integral methods is given below:ɛ=−ξ2p3γⅆln(∫1ξⅇ−γ/ξⅆξ)ⅆξ−p2ξp3γ−1Figure optionsDownload as PowerPoint slide