摘要
分别于真空和氮气气氛中,在1650,1750和1850℃对硅／碳化硅进行高温处理,通过光学显微镜、扫描电镜和X射线衍射仪研究了硅／碳化硅的组织变化。结果表明：氮气氛下,α子晶在界面能驱动下,通过基面以层状形式不断聚合长大,最终以完全“吞食”所包裹的β-SiC来完成相转变；在真空条件下,除了前一种方式外,还有一定的蒸发-凝聚烧结机制存在,两者同时作用使得比氮气条件下有较快的β-SiC转化速度。转化驱动力随温度的上升而提高。1850℃氮气环境下处理的材料仍有少量β相存在,而真空1750℃处理后就能得到单-α相的多孔材料。
Si/SiC materials were treated respectively in vacuum and nitrogen atmosphere at 1 650, 1 750 and 1 850 ℃. The transformation of microstructure in Si/SiC was investigated by means of optical microscopy, scanning electrion microscopy and X-ray diffraction. In nitrogen atmosphere the transformation mode was nucleation of α-SiC seed lamellae of base plane by interface energy drawn. In vacuum, two transformation modes of base plane nucleation and evaporation-coacervation were concurrently present, and β-SiC was transformed more quickly than in nitrogen atmosphere. The driven force of transformation increased with temperature. There was a little β-SiC phase present at 1 850 ℃ treated in nitrogen atmosphere, but single α-SiC phase porous material was obtained by treated at 1 750℃ in vacuum.
出处
《机械工程材料》
CAS
CSCD
北大核心
2006年第9期17-20,38,共5页
Materials For Mechanical Engineering
基金
国家"863"科技攻关资助项目(2001AA333010)
