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| Home > Publications database > Der Einfluß des Sauerstoffpartialdruckes auf das quasiternäre System Cr-Mn-Ti-Oxid |
| Home > Publications database > Der Einfluß des Sauerstoffpartialdruckes auf das quasiternäre System Cr-Mn-Ti-Oxid |
| Book/Report | FZJ-2018-03449 |
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1991
Forschungszentrum Jülich GmbH Zentralbibliothek Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/18879
Report No.: Juel-2475
Abstract: The passivation layers formed by the oxidizing corrosion of high temperature alloys consist primarily of oxides and mixed oxides of the elements chromium, manganese and titanium. For a reproducible formation and characterization of such oxide layers it is necessary to know the phase equilibria of these oxide systems at temperature and oxygen partial pressure conditions which will be relevant during their application. For the investigation of the quasi-ternary system Cr-Mn-Ti-oxide, oxide powders were prepared and annealed at 1000°C under different oxygen partial pressures ranging from 0.21 bar to 10$^{-21}$ bar. Phase identification and determination of lattice parameter using x-ray diffraction analysis as well as the direct measurement of phase boundaries as a function of oxygen partial pressure using the emf-methode were carried out for these investigations. In the quasi-ternary system Cr-Mn-Ti-oxide the spinels play a decisive role in the oxigen partial pressure range examined. The spinel MnCr$_{2}$O$_{4}$ may be regarded as the most significant compound. Part of the chromium canjoe replaced by trivalentmanganese at high oxygen partial pressures and by trivalent titanium at low pressures, and the formation of a solid solution with the spinel Mn$_{2}$TiO$_{4}$ is possible in all cases. In this way a coherent single-phase spinel region is observed which extends over the entire oxygen partial pressure range form 0.21 bar to10$^{-21}$ bar examined at 1000°C.
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