Advertisement

Determination of the Mechanism of Thermal Decomposition Reactions of Solids by Using the Cyclic and Constant Decomposition Rate Thermal Analysis Method

  • J. M. Criado

Abstract

The cyclic and Constant Rate Thermal Analysis technique (CRTA) has being used. The two rates automatically selected in the cyclic curve are small enough to allow the two states of the sample to be compared have nearly the same reacted fraction, α. Thus, the activation energy, E, can be calculated without prior knowledge of the actual reaction mechanism.

A procedure is developed for determining the kinetic law followed by the reaction by means of master curves that represent the values of α as a function of In A/C — E/RT,once E has been obtained from the cyclic CRTA diagram. The plots of α against E/RT must be superpossed upon the curve corresponding to the actual kinetic of the reaction by a lateral shift. The length of the lateral shift must be equal to In A/C, C being the constant rate and A the preexponential factor of Arrhenius. This procedure has been checked by studying the thermal decomposition of BaCO3.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. (1).
    J. M. Criado, Thermochim. Acta, 28 (1979) 307CrossRefGoogle Scholar
  2. (2).
    F. Rouquerol and J. Rouquerol, in “Thermal Analysis” (G. H. Wiedeman Ed.), Verlag, Basel and Stüggart, 1972, Vol. 1, p. 373Google Scholar
  3. (3).
    J. M. Criado and J. Morales, Thermochim. Acta 16 (1976) 382CrossRefGoogle Scholar
  4. (4).
    J. M. Criado and J. Morales, Thermochim. Acta 19, (1977) 305CrossRefGoogle Scholar
  5. (5).
    J. Rouquerol, Proceedings 2nd International Conference on Thermal Analysis, Worcester, U. S. A., 1968, Academic Press, New York 1969, Vol. 1, p. 281Google Scholar
  6. (6).
    J. Rouquerol, J. Thermal Anal. 5 (1973) 203CrossRefGoogle Scholar
  7. (7).
    F. Rouquerol, S. Regnier and J. Rouquerol, in “Thermal Analysis” (E. Buzag Ed.), Heyden, London 1975, Vol. 1, p. 313Google Scholar
  8. (8).
    J. H. Sharp, G. W. Brindley and N. N. Achar, J. Am. Ceram. Soc., 47 (1966) 379CrossRefGoogle Scholar
  9. (9).
    J. M. Criado, F. Rouquerol and J. Rouquerol, Thermochim. Acta, in the pressGoogle Scholar

Copyright information

© Springer Basel AG 1980

Authors and Affiliations

  • J. M. Criado
    • 1
  1. 1.Departamento de Química Inorgánica and Departamento de Investigacio-nes Físicas y Químicas, Facultad de QuímicaCentro Coordinado del C. S. I. C.SevillaSpain

Personalised recommendations