Authors:Eda Elmas, Kenan Yildiz, Nil Toplan, and H. Özkan Toplan
The effects of mechanical activation on the thermal behavior of kaolinite – alumina ceramic system and the non-isothermalkinetics of mullite formation were investigated and the following results were obtained.
In the kaolinite
Authors:Wenwei Wu, Xuehang Wu, Shuibin Lai, and Sen Liao
potential [ 11 – 13 ]. In this article, the mechanisms and kinetics of the decomposition of NH 4 ZrH(PO 4 ) 2 ·H 2 O were studied using TG–DTA technique. Non-isothermalkinetics of the decomposition process of NH 4 ZrH(PO 4 ) 2 ·H 2 O were interpreted by
The most debatable and discrepant viewpoints of non-isothermal kinetics are discussed in the form of twelve questions and answers. The reputation of non-isothermal kinetics when carried out by thermoanalysts; the consequences of simplified concepts transferred from the kinetics of homogeneous reactions; the physical meaning of basic kinetic parameters in solid-state processes; the kinetic compensative effect and interdependence of kinetic parameters using the Arrhenius rate constant; the mutual usefulness of differential and integral methods of kinetic data evaluation; their accuracy and correctness; the reliability of DTA measurements; non-isothermal versus isothermal investigations; equilibrium and kinetic data and their mutual effect; the extended discussion initiated by MacCallum and Tanner; non-isothermal data publication policy; and finally the use of computers.
Authors:Xuehang Wu, Wenwei Wu, Kaiwen Zhou, Xuemin Cui, and Sen Liao
-DSC technique. Non-isothermalkinetics of the thermal decomposition of precursor was interpreted by Flynm–Wall–Ozawa (FWO) method [ 18 , 19 ]. The kinetic ( E a , ln A , mechanism) parameters of the thermal decomposition of precursor MgFe 2 (C 2 O 4 ) 3 ·6H 2
Theoretical consideration has been made of the non-isothermal kinetics of consecutive reactions based on the superposition
principle. In the model the first reaction product reacts to form the final product and the two reactions proceed independently.
The amount of the first reaction product and the production rate of the final product have been obtained as a function of
time for isothermal cases and as a function of the reduced times for non-isothermal cases.
Authors:Zhipeng Chen, Qian Chai, Sen Liao, Yu He, Wenwei Wu, and Bin Li
2 O using TG–DTA technique. Non-isothermalkinetics of the decomposition process of α-LiZnPO 4 ·H 2 O was interpreted by a modified method [ 24 – 29 ], the apparent activation energy E a was obtained from iterative procedure [ 29 ], the most
It is shown that the total differential of the function of the amount of conversion versus temperature and time (α=f(T, t)) is equal to zero non-isothermal kinetics at constant heating rate. Hence, the mathematical expression used in the literature for the rate of the non-isothermal transformation,
, is not valid.
The authors continue their considerations concerning the validity of the steady-state approximation in non-isothermal kinetics.
A sequence of two first-order consecutive reactions with an active intermediate was subjected to kinetic analysis by numerical
solution of the corresponding differential kinetic equations for a number of particular cases. The results demonstrated that
the rate of change of concentration of the active intermediate is negligibly small if the assumption made in the isothermal
case is also accepted for the non-isothermal case, i.e. k2(T(t))>>