【摘要】 本研究采用sol-gel方法制备了Si-O-C纤维,利用IR和XRD监视纤维在不同热处理条件下化学结构的发展,用ICP-AES和SEM分析了热处理对纤维化学成分和显微组织的影响。结果表明:经1000℃氧气氛下分解后,纤维的力学性能达到最高,约为IGPa;该材料在1100℃的空气中具有良好的抗氧化能力;1300℃(氩气)以下处理后的纤维是无定型相;进一步加热导致碳化硅的生成和结晶,并伴随力学性能的下降。更多还原

【Abstract】 Amorphous silicon oxycarbide fibre has been prepared using sol-gel technique. It is found that under carefully controlled hydrolysis conditions and with secondary cellulose acetate as fibre-forming agent,vinyltrimethoxysilane could be hydrolysed to give a spinnable solution. IR and XRD investigation revealed that the as-spun fibre was converted into glassy silicon oxycarbide at 800～1300℃ in an inert atmosphere and maximium tensile strength around 1GPa was obtained for fibre pyrolysed at 1000℃. However, pronounced carbothermic reduction took place within the fibre above 1400℃ to form β-SiC, degrading fibre mechanical properties. The silicon oxycarbide fibre has good oxidation resistance. It loses only 2％ in mass after being exposed to air at 1000℃ for 10h.更多还原