Densification and grain growth behaviour of high-purity MgO ceramics by hot-pressing |
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| Affiliation: | 1. General Research Institute for Nonferrous Metals, Beijing 100088, PR China;2. Grikin Advanced Materials Co. Ltd., Beijing 102200, PR China;3. Beijing Engineering Research Center, Beijing 102200, PR China;1. Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Institute of Ceramics and Powder Metallurgy, School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China;2. Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang 110819, China;1. Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, 221116, China;2. Guangdong Provincial Key Laboratory of Materials for High Density Electronic Packaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China;3. School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, 30332, USA;1. Univ. Limoges, SPCTS, UMR CNRS 7315, F-87068 Limoges, France;2. LCTL, SPCTS, UMR CNRS 7315, F-87068 Limoges, France;3. ILT&SR, Polish Academy of Science, ul. Okólna 2, 50-422 Wroc?aw, Poland;1. College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China;2. Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China |
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| Abstract: | High-purity MgO ceramics with a relative density higher than 99.60% and a mean grain size of 8.1 µm were prepared by hot-pressing at 1450 °C and 35 MPa for 120 min. The MgO ceramic was 130 mm in diameter and 10 mm in height. The densification mechanism and grain growth of MgO powder during the sintering process were investigated based on the principles of general deformation and classical phenomenological kinetic theory. The threshold pressure of plastic deformation at the initial sintering stage was also analysed. The results suggest that plastic deformation is the dominant densification mechanism during the initial period and that an applied pressure of 20 MPa is sufficient for the deformation. During the final period, Mg2+ diffusion along the grain boundaries controls the densification process, and the grain growth activation energy at the final stage is estimated as 336.38±2.35 kJ mol?1. |
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| Keywords: | MgO Densification Grain size Hot-pressing |
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