Microstructure refinement and mechanical properties improvement of HfB₂-SiC composites with the incorporation of HfC

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• 作者：De-Wei Ni ; Ji-Xuan Liu ; Guo-Jun Zhang ; ^{gjzhang@mail.sic.ac.cn}
• 关键词：Hot pressing ; Mechanical properties ; Hafnium diboride ; UHTCs ; Synthesis
• 刊名：Journal of the European Ceramic Society
• 出版年：2012
• 期刊代码：53_09552219
• 类别：ms
• 出版时间：August, 2012
• 卷：32
• 期：10
• 页码：2557-2563
• 文件大小：989 K

摘要

HfB₂ and HfB₂-10 vol%HfC fine powders were synthesized by carbo/boronthermal reduction of HfO₂, which showed high sinterability. Using the as-synthesized powders and commercially available SiC as starting powders, nearly full dense HfB₂-20 vol%SiC (HS) and HfB₂-8 vol%HfC-20 vol%SiC (HHS) ceramics were obtained by hot pressing at 2000 掳C/30 MPa. With the incorporation of HfC, the grain size of HHS was much finer than HS. As well, the fracture toughness and bending strength of HHS (5.09 MPa m^1/2, 863 MPa) increased significantly compared with HS (3.95 MPa m^1/2, 654 MPa). Therefore, it could be concluded that the incorporation of HfC refined the microstructure and improved the mechanical properties of HfB₂-SiC ceramics.