Conversion Process of Amorphous Si-Al-C-O Fiber into Nearly Stoichiometric SiC Polycrystalline Fiber
Conversion Process of Amorphous Si-Al-C-O Fiber into Nearly Stoichiometric SiC Polycrystalline Fiber
复制标题
非晶Si-Al-C-O纤维转化为近化学计量SiC多晶纤维的过程
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
T. Ishikawa
中科院分区：
文献类型：
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作者：
Ryutaro Usukawa;H. Oda;T. Ishikawa
Tyranno SA（SiC-多晶纤维，宇部工业株式会社）显示出优异的耐热性高达2000℃，具有相对较高的机械强度。这种纤维是在氩气保护下，在1500℃以上的高温下，由Si-Al-C-O非晶纤维转变为SiC多晶纤维而制得的。在该转化过程中，进行非晶Si-Al-C-O纤维的降解反应，同时释放CO气体以获得化学计量组成，随后进行降解纤维的烧结。此外，Si-Al-C-O纤维中气态SiO的汽化、相变和各组分的主动扩散相互竞争。在这些变化中，转化过程中气态SiO的蒸发导致异常SiC晶粒生长，并且还导致非化学计量组成。然而，使用具有富氧表面的改性Si-Al-C-O纤维，有效地防止了气态SiO的蒸发，并且因此可以获得接近化学计量的SiC组合物。
Tyranno SA (SiC-polycrystalline fiber, Ube Industries Ltd.) shows excellent heat-resistance up to 2000℃ with relatively high mechanical strength. This fiber is produced by the conversion process from a raw material (amorphous Si-Al-C-O fiber) into SiCpolycrystalline fiber at very high temperatures over 1500℃ in argon. In this conversion process, the degradation reaction of the amorphous Si-Al-C-O fiber accompanied by a release of CO gas for obtaining a stoichiometric composition and the subsequent sintering of the degraded fiber proceed. Furthermore, vaporization of gaseous SiO, phase transformation and active diffusion of the components of the Si-Al-C-O fiber competitively occur. Of these changes, vaporization of the gaseous SiO during the conversion process results in an abnormal SiC-grain growth and also leads to the non-stoichiometric composition. However, using a modified Si-Al-C-O fiber with an oxygen-rich surface, vaporization of the gaseous SiO was effectively prevented, and then consequently a nearly stoichiometric SiC composition could be obtained.