High Temperature Material Processes (An International Quarterly of High-Technology Plasma Processes) An International Journal

ISSN for PRINT: 1093-3611

For Online Access

Best Paper Award Selection - Editorial Board Site

2002, Volume6

Issue 3

100 pages

Issue price - $144.00

Alexandra Maitre
Laboratoire Science des Procedes Ceramiques et Traitements de Surface UMR CNRS 6638 123 Avenue Albert-Thomas F-87060 Limoges Cedex, France

Pierre Lefort
Laboratoire Science des Precedes Ceramiques et Traitements de Surface UMR CNRS 6638 123 Avenue Albert-Thomas F-87060 Limoges Cedex, France

On the basis of a sintering model, the diffusion rates of a reactive system (Ti₃O₅/C giving Ti₂OC) were evaluated. Three elementary steps were considered: volumic diffusion through the neck supposed to be formed between two grains (C and Ti₃O₅) during their reaction ; surface diffusion on the external surface of the neck; gaseous diffusion of reactive gas (CO or CO₂). Theoretical diffusion rates were obtained/or a real powder bed with the estimate of the number of contacts between the grains following Cournil-Thomas's model. The comparison with the experimental rate of the reaction at 1523 К shows that the theoretical diffusion rates were 10³ to 10⁸ times higher. This confirms previous results which show that diffusion cannot be the limiting step of this system, in respect of the classical Langmuir-Hinshelwood's model. Such a kind of calculation could be extended to many other reactive systems.

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