High‐Temperature Phase Relations in the System Y2O3‐Ta2O5

Yoshiyuki Yokogawa, Masahiro Yoshimura

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31 Citations (Scopus)


The phase relations for the system y2o3–Ta2o5 in the composition range 50 to 100 mol% Y2O3 have been studied by solid‐state reactions at 1350°, 1500°, or 17000C and by thermal analyses up to the melting temperatures. Weberite‐type orthorhombic phases (W2 phase, space group C2221), fluorite‐type cubic phases (F phase, space group Fm3m)and another orthorhombic phase (O phase, space group Cmmm)are found in the system. The W2 phase forms in 75 mol% Y2O3 under 17000C and O phase in 70 mol% Y2O3 up to 1700°C These phases seem to melt incongruently. The F phase forms in about 80 mol% Y2O3 and melts congruently at 2454° 3°C. Two eutectic points seem to exist at about 2220°C 90 mol% Y2O3, and at about 1990°C, 62 mol% Y2O3. A Phase diagram including the above three phases were not identified with each other.

Original languageEnglish
Pages (from-to)2077-2081
Number of pages5
JournalJournal of the American Ceramic Society
Issue number9
Publication statusPublished - 1991 Sep

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry


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