Densification,mechanical and thermal properties of ZrC1 ? x ceramics fabricated by two-step reactive hot pressing of ZrC and ZrH2 powders |
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| Authors: | Boxin Wei Lei Chen Yujin Wang Haibin Zhang Shuming Peng Jiahu Ouyang Dong Wang Yu Zhou |
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| Affiliation: | 1. Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Heilongjiang, Harbin 150080, China;2. Innovation Research Team for Advanced Ceramics, Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Sichuan, Mianyang, 621900, China |
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| Abstract: | Densification behavior, mechanical and thermal properties of ZrC1 ? x ceramics with various C/Zr ratios of 0.6–1.0 have been investigated by two-step reactive hot pressing of ZrC and ZrH2 powders at 30 MPa and 1500–2100 °C. The two-step reactive hot pressed ZrC1 ? x ceramic has a higher relative density (> 95.3%) than that (91.9%) of stoichiometric ZrC sintered at 2100 °C. A cubic Zr2C-type ordered phase forms in the ZrC1 ? x sample obtained at a ZrC/ZrH2 molar ratio of 0.6 at a relatively low temperature of 1100 °C. The decrease in C/Zr ratio is beneficial to densification of ZrC1 ? x ceramic, however, excess grain growth occurs after sintering above densification temperature. The elastic modulus and Vickers hardness decrease with decreasing the C/Zr ratio. With decreasing the C/Zr ratio, both thermal conductivity and specific heat decrease due to the enhanced scattering of conducting phonons and electrons by carbon vacancies. |
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| Keywords: | Reaction sintering Densification Mechanical properties Thermal properties |
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