Phase relations and spectral properties of new phases in Sc₂O₃–V₂O₅–Nb₂O₅–Ta₂O₅ system

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• 作者：E.V. Arkhipova ; M.G. Zuev and L.A. Perelyaeva
• 关键词：Quaternary phase diagram ; Solid solutions ; Optical and IR spectroscopy
• 刊名：Journal of Alloys and Compounds
• 出版年：2006
• 出版时间：13 April 2006
• 年：2006
• 卷：414
• 期：1-2
• 页码：48-54
• 全文大小：429 K

文摘

Phase relations in the Sc₂O₃–V₂O₅–Nb₂O₅–Ta₂O₅ system up to 950 °C have been analyzed. Solid solutions ScNb_{1 − x}Ta_xO₄ (x = 0–1) with the wolframite structure (FeWO₄, the space group P2₁/n) and ScNb_{2 − 2x}Ta_2xVO_{9 − δ} (x = 0–1) with the tetragonal structure (the space group I), and also a region of a three-dimensional solid solution based on VNb₉O₂₅, which is limited by compounds TaNbV₂O₁₀, ScNb₂VO₉, ScTa₂VO₉, VNb₉O₂₅ and VTa₉O₂₅, were detected in this system. Elementary tetrahedrons have been found in the Sc₂O₃–V₂O₅–Nb₂O₅–Ta₂O₅ system. Solid solutions ScNb_{1 − x}Ta_xO₄ and ScNb_{2 − 2x}Ta_2xVO_{9 − δ} were studied by the methods of vibrational and optical spectroscopy. It was found that the forbidden gap in these solid solutions increased and decreased with growing concentrations of tantalum and niobium atoms, respectively. A correlation between optical and IR spectroscopic data was established.