High-Temperature Phase Relations in the System Gd2O3-Ta2O5 |
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Authors: | Yoshiyuki Yokogawa Nobuo Ishizawa Shigeyuki Smiya Masahiro Yoshimura |
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Affiliation: | Research Laboratory of Engineering Materials, Tokyo Institute of Technology, Yokohama 227, Japan |
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Abstract: | The Phase relations of the system Gd2O3-Ta2O5 in the composition range 50 to100 mol% Gd2O3 was studied by solidstate reactions at 1350°, 1500°, or 1700°C and by thermal analyses up to the melting temperatures. Weberite-type orthorhombic phase (W2 phase, space group C2221) with the composition of Gd3 TaO7 seems to melt incongruently; at about 2040°C, although this Gd3TaO7 Phase was previously reported to melt congruently. A new fluorite-type cubic phase (F phase, space group Fm3m ) was found for the first time above 1500°C in the system. It melts congruently with the composition of about 80mol% Gd2O3at 2318° 3°C. A phase diagram was proposed for the system Gd2O3–Ta2O5 in the Gd2O3–rich portion |
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Keywords: | Phases gadolinium oxide tantalum oxide systems thermal analysis |
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