| Autor: |
Rousset, A., Clerc, L., Vajpei, A. C., Gillot, B., Jemmali, F. |
| Zdroj: |
Journal of Thermal Analysis and Calorimetry; May 1987, Vol. 32 Issue: 3 p845-855, 11p |
| Abstrakt: |
Non-isothermal and isothermal TG studies on the cation distribution in submicronic titanomagnetites; Fe3−xTixO4 with 02O3. The DTA results show that the temperature of oxidation of Fe2+ to Fe3+ ions is increased, whereas the temperature of phase change is decreased with increasing titanium substitution. The kinetics of oxidation is found to be governed by the law of diffusion for variable working conditions and for different extents of the vacancies created at the solid-gas interface. The diffusion of iron(II) ions located at octahedral sites proceeds with a lower activation energy than that of iron(II) ions located at tetrahedral sites. Diffusion rates were discerned to be composition-dependent and the variations can be identified with the distribution of the iron ions in sublattices. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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