自蔓延高温合成氮化硅多孔陶瓷的研究进展

多孔氮化硅陶瓷兼具有高气孔率和陶瓷的优异性能, 在吸声减震、过滤等领域具有非常广泛的应用。然而, 目前常规的制备方法如气压/常压烧结、反应烧结-重烧结以及碳热还原烧结存在烧结时间长、能耗高、设备要求高等不足, 导致多孔Si₃N₄陶瓷的制备成本居高不下。因此, 探索新的快速、低成本的制备方法具有重要意义。近年来, 采用自蔓延高温合成法直接制备多孔氮化硅陶瓷展现出巨大潜力, 其可以利用Si粉氮化的剧烈放热同时完成多孔氮化硅陶瓷的烧结。本文综述了自蔓延反应的引发以及所制备多孔氮化硅陶瓷的微观形貌、力学性能和可靠性。通过组分设计和工艺优化, 可以制备得到氮化完全、晶粒发育良好、力学性能与可靠性优异的多孔氮化硅陶瓷。此外还综述了自蔓延合成多孔Si₃N₄陶瓷晶界相性质与高温力学性能之间的关系, 最后展望了自蔓延高温合成多孔Si₃N₄陶瓷的发展方向。

Progress of Porous Silicon Nitride Ceramics Prepared via Self-propagating High Temperature Synthesis

Porous silicon nitride (Si₃N₄) ceramics can be widely used in various fields, such as sound and shock absorption, filtration and so on, due to its high porosity and outstanding properties of ceramics. However, conventional preparation methods, such as gas-pressure/pressureless sintering, sintering reaction-bonded sintering and carbothermal reduction sintering, perform long sintering time, high energy consumption and high equipment requirements, which makes the preparation of porous Si₃N₄ ceramics expensive. Therefore, it is of great importance to explore a rapid and low-cost preparation method. In recent years, the direct preparation of porous Si₃N₄ ceramics by self-propagating high temperature synthesis (SHS) has showed great potential of which the heat released from the nitridation of Si powder could be used for the in-situ sintering of porous Si₃N₄ ceramics. In present paper, researches relating to the initiation of the SHS reaction, and microstructural evolution, mechanical properties, and reliability of the fabricated Si₃N₄ ceramics are summerized systematically. Porous Si₃N₄ ceramics with complete nitridation, excellent grain morphology and outstanding mechanical properties and reliability are obtained by adjusting raw materials and process parameters. Furthermore, the relationship between properties of grain boundary phase and high-temperature mechanical properties of SHS-fabricated porous Si₃N₄ ceramics is reviewed. Finally, the development direction of the self-propagating high temperature synthesis of porous Si₃N₄ ceramics is prospected.