Pressureless Sintering of High-Density ZrB2–SiC Ceramic Composites |
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Authors: | Yongjie Yan Zhengren Huang Shaoming Dong Dongliang Jiang |
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Affiliation: | Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, China |
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Abstract: | Ultra-high-temperature ceramic composites of ZrB2 20 wt%SiC were pressureless sintered under an argon atmosphere. The starting ZrB2 powder was synthesized via the sol–gel method with a small crystallite size and a large specific surface area. Dry-pressed compacts using 4 wt% Mo as a sintering aid can be pressureless sintered to ∼97.7% theoretical density at 2250°C for 2 h. Vickers hardness and fracture toughness of the sintered ceramic composites were 14.82±0.25 GPa and 5.39±0.13 MPa·m1/2, respectively. In addition to the good sinterability of the ZrB2 powders, X-ray diffraction and scanning electron microscopy results showed that Mo formed a solid solution with ZrB2, which was believed to be beneficial for the densification process. |
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