2.45 GHz microwave sintered Si_3N_4-ZrO_2 composites(<Feature>SiAlons and Non-oxides)
スポンサーリンク
概要
- 論文の詳細を見る
An investigation has been made of the use of 2.45 GHz microwave energy to sinter Si_3N_4-ZrO_2 (4 mol% Y_2O_3 stabilized) composites with 5 mass% MgO as a densifying aid at 1600℃ to avoid the formation of ZrN. XRD phase analysis showed the presence of ZrN in all the sintered samples. Higher temperature developed within the specimen favored the reaction between Si_3N_4 and ZrO_2 to form ZrN. SEM microstructures revealed elongated β-Si_3N_4 grains with high aspect ratio. Indentation fracture toughness of the composites increased with increasing weight fraction of ZrO_2. Cracks were propagated intergranularly through Si_3N_4/ZrO_2 interfaces and transgranularly through ZrO_2 grains with many microcracks in the process zone of the main crack. The results indicated that the dominant toughening mechanisms operating were crack deflection and bridging in the case of 0 mass% ZrO_2 and 10 mass% ZrO_2 whereas crack deflection, bridging and microcrack toughening were observed when the amount of ZrO_2 in the composites increased to 25 and 40 mass%.
- 2008-06-01
著者
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Chockalingam Sreekumar
Kazuo Inamori School Of Engineering At Alfred University
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AMARAKOON Vasantha
Kazuo Inamori School of Engineering at Alfred University