研究了木材制备ＳｉＣ陶瓷的反应过程及熔融硅与多孔木炭反应的机理．结果表明，木材制得的ＳｉＣ陶瓷的最终组织取决于渗硅处理温度．较低温度下形成碳化硅多孔材料，较高温度下形成 Ｓｉ／ＳｉＣ复相致密材料．分析指出，木材制备 ＳｉＣ陶瓷中 Ｓｉ／Ｃ反应的大致过程为：熔融硅沿木炭毛细管壁上升，同时与接触的碳反应形成碳化硅，碳化硅层不断向碳层推进直至多孔碳骨架完全转化为碳化硅．生成的碳化硅在反应后期会发生再结晶，最终组织形态表现为多边形大颗粒碳化硅分布在自由硅基体上．
The process of reaction of silicon carbide ceramics derived from wood was investigated. The reaction
mechanism was also analyzed. The results show that the temperature of silicon infiltration determines the ultimate microstructure of SiC
ceramics. Porous SiC materials are formed at lower temperature, while at higher temperature, compact Si/SiC composite materials formed.
The process of silicon-carbon reaction can be described as three steps: (1) Melted Si ascends via capillary of charcoal and reacts with contacted carbon forming silicon carbide.
(2) The thickness of SiC layer increases toward carbon layer till the end. (3) Reaction-formed SiC will re-crystallize in the later
stage of the reaction, and the ultimate microstructure is composed of large size of polygonal SiC and free Si.
参考文献
| [1] | Ota Toshitaka, Takahashi Minoru. J. Am. Ceram. Soc., 1995, 78 (12): 3409--3411. [2] Hong Zhou, Raj N Singh. J. Am. Ceram. Soc., 1995, 78 (9): 2456--2462. [3] Fitzer E, Gadow R. Am. Ceram. Soc. Bull., 1986, 65: 326. |
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