ISSN:
1572-8943
Keywords:
Constant Rate Thermal Analysis (CRTA)
;
solid state kinetics
;
Stepwise Isothermal Analysis (SIA)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The results obtained in this work point out that both SIA and CRTA traces, simulated assuming the same values of the reaction rate, are identical provided that either 'n order’ or diffusion controlled kinetics are concerned. The α-T CRTA plots of solid state reactions fitting an Avrami-Erofeev kinetic model show that the temperature decreases with increasing α until reaching a minimum at a value of the reacted fraction α = αmin characteristic of the Avrami-Erofeev exponent. The shapes of the corresponding SIA diagrams are quite different and a very long isothermal step is obtained. Moreover, the reaction rate is not maintained constant during the isothermal period but it shows a maximum at a value of α depending on the Avrami-Erofeev coefficient. It is important to point out that this αmax value agrees with the corresponding αmin calculated from a CRTA curve by assuming the same Avrami-Erofeev exponent.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1010172821020
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