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原位增韧SiC-YAG复相陶瓷的致密化

黄政仁; 谭寿洪; 江东亮; 赵诚宰+   

  1. 中国科学院上海硅酸盐研究所, 上海 200050; +韩国标准科学研究院, 大田 韩国
  • 收稿日期:1999-02-11 修回日期:1999-03-05 出版日期:1999-10-20 网络出版日期:1999-10-20

Densification of in-situ Toughened SiC-YAG Composites

HUANG Zheng-Ren; TAN Shou-Hong; JIANG Dong-Liang, CHO Seong-Jai+   

  1. Shanghai Institute of Ceramics; Chinese Academy of Sciences Shanghai 200050 China;-+Korea Research Institute of Standards and Sciences; Tajeon; Korea
  • Received:1999-02-11 Revised:1999-03-05 Published:1999-10-20 Online:1999-10-20

摘要: 以β-SiC粉加入少量作为晶种的α-SiC为起始原料,通过高温热处理过程中的相变和长柱状晶粒生长来制备原位增韧SiC基复相陶瓷;调整埋烧工艺控制高温热处理过程中液相挥发和保持稳定的化学计量比,以保证液相全部晶化为YAG相,着重解决了长柱状晶粒生长过程中的致密化.发现在完全形成紧密的网络状结构之前,长柱状晶粒的形成可能延缓致密化速率,但不会由此中止致密化过程.通过调整热处理条件,制备得到了完全致密化(>99%理论密度)并具有优异断裂韧性(1c=6.9MPa·m1/2,SEPB法)的原位增韧SiC-YAG复相陶瓷.

关键词: 原位增韧, 液相烧结, 碳化硅, YAG

Abstract: Densification, β→α phase transformation, elongated SiC grain growth and microstructure, and mechanical properties, especially toughness, of in-situ
toughened SiC-YAG composites were investigated in detail. By using packing powders with same compositions as packed samples, the evaporation of Al2O3
was inhibited and full densification (>99% of theoretical density) of in-situ toughened SiC-YAG was achieved. The β→α phase transformation occurrs at
1950℃, however, remained β-SiC can be still found by XRD after post-heated at 2100℃ for 4h. The content of liquid phase and α-SiC seeds has no effect on the phase transformation rate.
Following phase transformation and grain growth during post-heating, further densification of in-situ SiC-YAG continues and the network microstructure
consisting of elongated SiC grains can be obtained. Finally, the SEPB fracture toughness achieved is near 7.0 MPa·m1/2.

Key words: in-situ toughening, liquid phase sintering, Silicon Carbide, YAG

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