窒化ケイ素セラミックスの高温酸化挙動に及ぼす焼結助剤およびSiC添加の影響

概要

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High temperature oxidation behavior of Si_3N_<4->based ceramics was investigated systematically. The test has been made at 13000C in dry air environment up to 2000 hours. The Si_3N_4 specimens tested were as follows, a) S-l : Si_3N_4 added 8mass% Y_2O_3. b) S-2 : Si_3N_4 /SiC added 8mass% Y_2O_3. c) S-3 : Si_3N_4 added 5mass% Y_2O_3 and 3mass%Al_2O_3. d) S-4 : Si_3N_4 /SiC added 5mass% Y_2O_3 and 3mass%Al_2O_3. The main conclusions are as follows. 1) Oxidized layer thickness of S-3 and S-4 were much thicker than those of S-1 and S-2. 2) Relationship between the oxidation time and oxi dized layer thickness obeyed the parabolic law in all specimens. 3) The Y concentration under the oxidized layer was reduced considerably. The zone was defined as diffused layer. The thickness of diffused layer was very large in S-3 and S-4 samples. 4) Crystalline phases in the oxidized layer were mainly SiO_2 and Y_2Si_2O_7. 5) Effect of SiC composition on the oxidation behavior was slight.
社団法人日本材料学会の論文
2002-11-15