自增韧热压氮化硅陶瓷的研究

详细信息

SELF-REINFORCED HP SILICON NITRIDE CERAMICS

摘要

摘要: 本文对自增韧热压Si₃N₄陶瓷材料进行了研究,着重研究了材料的自增韧机理,Y₂O₃与La₂O₃之间的配比和(Y₂O₃+La₂O₃)的重量含量对自增韧热压氮化硅陶瓷结构及性能的影响。对最优助剂含量和配比的热压氮化硅试样进行了氧化行为和抗热震性的研究。研究发现热压氮化硅陶瓷材料的自增韧机理为β-Si₃N₄柱状晶使裂纹发生桥接和偏转。当Y₂O₃La₂O₃=11且(Y₂O₃+La₂O₃)为20wt%时,1350℃时的抗弯强度达最大值(σf^1350℃为715MPa),且(Y₂O₃+La₂O₃)为16wt%时,室温的断裂韧性达最大值(K_IC^RT为7.8MPa·m^1/2).1150℃热压氮化硅材料经200小时氧化处理,内部析出针状晶体。经1100℃→100℃多次热循环后,强度下降的主要原因是裂纹的产生和扩展。
- 自增韧 /
- 热压氮化硅 /
- 力学性能
Abstract: For the self-reinforced HP Si₃N₄ ceramics, the effects of(Y₂O₃+La₂O₃) wt% and the ratio between Y₂O₃ and La₂O₃ on the mechanical properties and microstructure were studied. Analysis of toughening processes indicated that both crack deflection and -Si₃N₄ bridging mechanisms can contribute to the fracture toughness of HP-Si₃N₄ ceramics. Inaddition, the oxidizing behavior and feature of subjecting to thermal cycling were studied in this paper.
- self-reinforce, silicon nitride, mechanical properties, microstructure /
- undefined /
- undefined