Biomorphic porous Si/SiC ceramics were prepared by liquid silicon infiltration-reaction and subsequent removal of residual Si. The microstructure morphology and component analysis of the cellular Si/SiC were investigated by means of scanning electron microscopy and X-ray diffraction. The porosity and distribution of the pore diameter of porous Si/SiC were determined by mercury intrusion method. Results show that the resulting porous ceramic is composed of major crystal phase β-SiC and secondary phase residual free Si. The ceramic composite maintained the original morphology of the wood and exhibited a porosity of 16%~32% by controlling the for Si removal time. The Archimedes and three-point bending methods were used to test the apparent porosity and bending strength of porous SiC ceramic. The influences of the Si removal time on the final phase composition and mechanic properties of the formed biomorphic Si/SiC ceramic composite were analyzed. The formation mechanism of SiC was also discussed.%榉木经高温热解转化为生物碳模板,经液相渗硅反应(LSIP),在1 550 ℃、渗硅1.5 h、1 700 ℃抽真空排硅制备了保持木材微观结构的多孔Si/SiC生态陶瓷. 利用X射线衍射分析(XRD)和扫描电子显微镜(SEM)及压汞技术对样品的物相构成、显微结构和孔径分布进行了测试分析. 利用阿基米德法和三点弯曲法测定了多孔陶瓷的气孔率、密度和弯曲强度. 结果表明,最终产物由主晶相β-SiC和少量Si组成,控制高温排硅时间可以得到孔隙率为16%~32%的多孔Si/SiC生态陶瓷,可调控其产物的相组成和力学性能. 对LSIP工艺的反应机理进行了探讨.
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