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Microstructure, mechanical and thermo-physical properties of hot-pressedAl2O3-GdAlO3-ZrO2 ceramics with eutectic composition |
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| Authors: | Abdelkhalek Henniche Jiahu Ouyang Yonghui M Zhigang Wang Zhanguo Liu Yujin Wang Mehdi Derradji Xinyu Liu |
| Affiliation: | Laboratoire Génie des Matériaux, école Militaire Polytechnique, BP17 Bordj El-Bahri, 16046 Algiers, Algeria,School of Materials Science and Engineering, Harbin Institute of Technology, 92 Westdazhi Street, Harbin 150001, China,School of Materials Science and Engineering, Harbin Institute of Technology, 92 Westdazhi Street, Harbin 150001, China,School of Materials Science and Engineering, Harbin Institute of Technology, 92 Westdazhi Street, Harbin 150001, China,School of Materials Science and Engineering, Harbin Institute of Technology, 92 Westdazhi Street, Harbin 150001, China,School of Materials Science and Engineering, Harbin Institute of Technology, 92 Westdazhi Street, Harbin 150001, China,Institute of Composite Materials, Key Laboratory of Superlight Material and Surface Technology of Ministry of Education, College of Materials Science andChemical Engineering, Harbin Engineering University, Harbin 150001, China and School of Materials Science and Engineering, Harbin Institute of Technology, 92 Westdazhi Street, Harbin 150001, China |
| Abstract: | A low cost chemical co-precipitation method was employed to fabricate nanoscale Al2O3-GdAlO3-ZrO2 powder with eutectic composition. A careful control of reaction conditions was required during the preparation. The synthesized nanopowders exhibited a particle size of 20–200 nm, and were highly dispersive and uniform. The results showed that calcination temperature had an important influence on the phase constituents of the nanopowders. With increasing the calcination temperature, a phase transformation from Ɵ-Al2O3 to α-Al2O3 and a thermal decomposition from Gd3Al5O12 (GdAG) to GdAlO3 and α-Al2O3 occurred in sequence. A calcination temperature of 1300 °C was needed for the crystallization of α-Al2O3. These nanosized powders were consolidated via hot pressing to produce a fully densified ceramic composite with eutectic composition. The Al2O3-GdAlO3-ZrO2 ceramic hot-pressed at 1500 °C exhibited a relative density of 99.4%, a flexural strength of 485 MPa and a fracture toughness of 6.5 MPa m1/2. The ceramic had a thermal conductivity of 1.9 W m K−1 at 1200 °C and a thermal expansion coefficient of 9.49 × 10−6 K−1 at 1100 °C. |
| Keywords: | Al2O3-GdAlO3-ZrO2 systemCo-precipitation hot pressingFlexural strength thermal conductivity |
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