Study of the TiC$_{1-x}$ – TiO$_2$ reactive interface

Abstract : The TiC$_{1-x}$–TiO$_2$ reactive interface obtained at 1100 °C has been studied by local structural investigations using Transmission Electron Microscopy (TEM) and X-rays microdiffraction. These results were completed by coupling complementary chemical characterizations by Nuclear Reaction Analysis (NRA), Rutherford Backscattering (RBS) and STEM (Scanning Transmission Electron Microscopy). A complex pattern of reactive interlayers of various thicknesses was formed as a result of the crossed redox reactions between TiO$_2$ and TiC$_{1-x}$. Our results show that the TiC$_{1-x}$ carbide is not oxidized by forming TiC$_x$O$_y$ oxycarbides in spite of the complete solid solution existing between TiC$_{1-x}$ and TiO$_2$. TiC$_{1-x}$ is in fact destabilized by the oxygen liberated during the transformation of TiO$_2$ into Magnéli type compounds (Ti$_n$O$_{2n-1}$) to form the most reduced Magnéli sub-oxides following the reaction: 3 TiC$_x$O$_y$ + (5-3y)/2 O$_2$ = Ti$_3$O$_5$ + 3x C. Starting from TiO$_2$, a progressive reduction is achieved showing spatially distributed Ti$_n$O$_{2n-1}$ Magnéli phases characterized by high values of n close to TiO$_2$ and lower values of $n$ as reaching TiC$_{1-x}$. The most reduced term is shown to be Ti$_3$O$_5$. Ti$_3$O$_5$ thus represents the final product of the reaction at 1100 °C both for the reaction of reduction of TiO$_2$ and for the reaction of oxidation of TiC$_{1-x}$.
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https://hal-cea.archives-ouvertes.fr/cea-01681190
Contributeur : Serge Palacin <>
Soumis le : jeudi 11 janvier 2018 - 14:11:43
Dernière modification le : jeudi 18 janvier 2018 - 01:39:13

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F. Réjasse, G. Trolliard, J. Léchelle, O. Rapaud, P. Carles, et al.. Study of the TiC$_{1-x}$ – TiO$_2$ reactive interface. Acta Materialia, Elsevier, 2018, 〈https://www.sciencedirect.com/science/article/pii/S1359645418300119〉. 〈10.1016/j.actamat.2017.12.055〉. 〈cea-01681190〉

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