材料科学
复合材料
抗弯强度
氮化硅
热冲击
断裂韧性
氮化物
烧结
纳米线
制作
陶瓷
多孔性
纳米技术
图层(电子)
替代医学
病理
医学
作者
Duan Li,Bin Li,Xuejin Yang,Shitao Gao,Yuanyi Zheng
标识
DOI:10.1016/j.jeurceramsoc.2018.02.001
摘要
The in situ silicon nitride nanowires reinforced porous silicon nitride (SNNWs/SN) composites were fabricated via gelcasting followed by pressureless sintering. SNNWs were well distributed in the porous silicon nitride matrix. The tip-body appearance suggested a VLS growth mechanism. The flexural strength and elastic modulus of the prepared composites can achieve 84.3 ± 3.9 MPa and 23.3 ± 2.0 GPa respectively (25 °C), while the corresponding porosity was 40.7 vol.%. Remarkably, the strength retention rate of the composites at 1400 °C was up to 66.1%. This is due to the excellent thermal stability of SNNWs and silicon nitride matrix. Also, the fracture toughness of the composites was improved to ∼42% larger than pure porous silicon nitride ceramics because of the bridging effect of the NWs and the interlocking effect of β-Si3N4 crystals. In addition, a good thermal shock resistance and dielectric properties were indicated. The good overall performance made SNNWs/SN composites promising candidate for advanced high-temperature applications.
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