Mechanical Properties of Hot Isostatically Pressed Zirconia-Toughened Alumina Ceramics Prepared from Coprecipitated Powders |
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Authors: | Yosuke Matsumoto Ken Hirota Osamu Yamaguchi Suguru Inamura Hiroki Miyamoto Nobuaki Shiokawa Kazuhiro Tsuji |
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Affiliation: | Department of Applied Chemistry, Faculty of Engineering, Doshisha University, Kyoto 602, Japan;Osaka Prefectural Institute of Industrial Technology, Osaka 550, Japan;Osaka Cement Co., Ltd., Osaka 597, Japan |
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Abstract: | Amorphous Al2O3–ZrO2 composite powders with 5–30 mol% ZrO2 have been prepared by adding aqueous ammonia to the mixed solution of aqueous aluminum sulfate and zirconium alkoxide containing 2-propanol. Simultaneous crystallization of γ-Al2O3 and t -ZrO2 occurs at 870°–980°C. The γ-Al2O3 transforms to α-Al2O3 at 1160°–1220°C. Hot isostatic pressing has been performed for 1 h at 1400°C under 196 MPa using α-Al2O3– t -ZrO2 composite powders. Dense ZrO2-toughened Al2O3 (ZTA) ceramics with homogeneous-dispersed ZrO2 particles show excellent mechanical properties. The toughening mechanism is discussed. The microstructures and t / m ratios of ZTA are examined, with emphasis on the relation between strength and fracture toughness. |
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