| 摘要 |
PURPOSE:To attain high denseness at low temp. and to improve strength and oxidation resistance at high temp. by firing a molded body consisting of the oxide of a rare earth element, vanadium oxide, the oxide of an element such as Nb, Ta or Cr and silicon nitride under prescribed conditions. CONSTITUTION:Starting material consisting of 1-20wt.% oxide of a rare earth element, 0.5-8wt.% vanadium oxide, 0.5-8wt.% oxide of Nb, Ta, Cr, Mo or W and the balance silicon nitride is mixed and a molded body of this mixture is subjected to primary firing at 1,700-1,900 deg.C under <=10 atm pressure of a nitrogen atmosphere and secondary firing at >=1,600 deg.C under >=50 atm pressure of the same nitrogen atmosphere. |
