Continuous sol–gel derived SiOC/HfO2 fibers with high strength
Continuous sol–gel derived SiOC/HfO2 fibers with high strength
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DOI：
10.1039/c4ra14540b
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发表时间：
2015-04
期刊：
影响因子：
3.9
通讯作者：
Yao Xu;Dong Su;Hongjun Feng;Xiao-xia Yan;Ning Liu;Yongqiang Sun
中科院分区：
文献类型：
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作者：
Yao Xu;Dong Su;Hongjun Feng;Xiao-xia Yan;Ning Liu;Yongqiang Sun
本研究采用溶胶-凝胶法制备了高强度的SiOC/HfO 2连续纤维。以聚乙烯吡咯烷酮（PVP）为纺丝剂，以硅醇盐和二氯化铪为原料，纺制出了连续的聚硅氧烷（PHfSO）凝胶纤维，经干燥和热解处理，得到了致密、收缩均匀的SiOC/HfO 2纤维。傅立叶变换红外光谱、X射线光电子能谱和X射线衍射分析表明，非晶态SiOC/HfO 2纤维由碳氧化硅（SiOxC 4 −x，x = 1-4）和四价的铌氧单元组成，并被一定的游离碳相包围。扫描电子显微镜和透射电子显微镜的观察表明，具有均匀的Hf分布的SiOC/HfO 2纤维表现出圆形或椭圆形的横截面取决于其厚度时，作为凝胶纤维。力学性能测试表明，SiOC/HfO 2纤维具有良好的力学性能，由于SiOC网络中引入了Hf，其最大拉伸强度为1.5GPa。
This study presents the fabrication and characterization of continuous SiOC/HfO2 fibers with high strength by the sol–gel process. Continuous polyhafnosiloxane (PHfSO) gel fibers are spun from the solutions of silicon alkoxides and hafnium dichloride using polyvinyl pyrrolidone as a spinning reagent, and then transform into dense SiOC/HfO2 fibers with homogeneous shrinkage by subsequent drying and pyrolysis treatment. Fourier transform infrared and X-ray photoelectron spectra together with X-ray diffraction analysis indicate that the amorphous SiOC/HfO2 fibers consist of mixed silicon oxycarbide (SiOxC4−x, x = 1–4) and tetravalent hafnium–oxygen units embraced with a certain free-carbon phase. Scanning electron microscopy and transmission electron microscopy observations reveal that the SiOC/HfO2 fibers with homogenous Hf distribution exhibit a circular-shaped or an elliptical-shaped cross-section depending on their thickness when employed as gel fibers. Mechanical testing shows that the SiOC/HfO2 fibers exhibit good mechanical property with the maximum tensile strength of 1.5 GPa arising from the incorporation of Hf in the SiOC network.