Thermogravimetric Study of the M-Co-O System: I, M = Ta and Nb at 1200°C |
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Authors: | Kenzo Kitayama |
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Affiliation: | Department of Chemistry, Faculty of Science, Tokyo Institute of Technology, Ookayama, Tokyo 152, Japan |
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Abstract: | Phase equilibria in the Ta-Co-O and Nb-Co-O systems have been studied at 1200°C at oxygen partial pressures from 10?0.68 to 10?13.50 atm for the former and from 10?0.68 to 10?13.30 atm for the latter. In both systems, M2CoO6 and M2Co4O9 are stable ternary compounds under the experimental conditions, and a new phase, Nb5Co2O14, has been identified. The Ta-Co-O system is simple, whereas the Nb-Co-O system is somewhat more complicated because of the extra phase. The lattice constants of the ternary compounds have been determined and compared with previous values. The standard Gibbs energies of reactions have been determined using oxygen partial pressures in equilibrium with three solid phases. |
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Keywords: | phase equilibria thermogravimetry cobalt tantalam niobium |
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