酸素雰囲気中におけるSi_3N_4常庄焼結体の高温酸化(<小特集>セラミック材料)

概要

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Six kinds ofpressureless sintered Si_3N_4 With three different additives (CeO_2-Al_2O_3-MgO, Y_2O_3-Al_2O_3, Y_2O_3-A1_2O_3 MgO) were rapidly heated up to1400℃ and then held at this temperature for 15h in pure oxygen. During the oxidation, N_2, NO and CO_2 concentrations in the exhaust gas were continuously measured by a mass spectrometer. In every sample, a good correlation was observed be tween the amount of N_2 formed and weight gain. Thea mount of N_2 formed and weight gain after oxidation of Si_3N_4 increased with decreasing sintering temperature. The rates of N_2 and NO formation in Creased rapidly for 5 min after the beating temperature reached 1400C and then decreased rapidly. After rapid decrease, the N_2 formation curve showed different behavior with three additives. The maximum N_2 formation rate was in the order Y_2O_3-Al_2O_3 MgO>CeO_2-Al_2O_3-Mg0>Y_2O_3Al_20_3. The total amount of N_2 formed was in the order Y_2O_3-Al_2O_3 MgO>CeO_2-Al20_3-MgO≒Y_2O_3-Al_2O_3. From the Si_3N_4 With CeO_2-Al_2O_3-MgO, a large amount of CO_2 was released and the surface of oxide scale was rough.
社団法人日本材料学会の論文
1991-04-15