Preparation and properties of silicon oxycarbide fibers
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Silicon oxycarbide fibers have been prepared from vinyl trimethoxysilane (VTMS) by a modified sol–gel method and with secondary cellulose acetate (SCA) as the fiber-forming aid. Its main advantage over a normal sol–gel fiber processing is that the spinning dope remains spinnable for a long period of time. The effect of the pre-hydrolysis of VTMS on the dope spinnability is studied. At H2O/VTMS = 4, the resultant sol transforms into gel very quickly, unsuitable to obtain a spinnable dope; at H2O/VTMS = 2, too much un-reacted VTMS exists in the sol, making the extruded fiber difficult to solidify; at H2O/VTMS = 3, a dope with good spinnability and stability, and thus high ceramic yield is obtainable. Pyrolysis at 1,000 °C in argon/5% hydrogen results in silicon oxycarbide fibers with the maximum tensile strength (940.0 MPa), moderate Young’s modulus (63.2 GPa) and high carbon content (33.2%).
KeywordsPyrolysis Silicon Carbide Pyrolysis Temperature High Carbon Content Carbothermal Reduction
The project is sponsored by Natural Science Foundation of China, No. 50472056, and China’s “863 scheme”, No. 2002AA305101. A part of the work was carried out under the supervision of Professor F. L. Riley (School of Materials, University of Leeds, England) and Professor G. C. East (Department of Textile Industries, University of Leeds, England).
- 1.Yajima S, Hayashi J, Omori M (1975) Chem Lett 45:931Google Scholar
- 5.White DA, Oleff SM, Boyer RD, Budinger PA, Fox JR (1987) Adv Ceram Mater 2:42Google Scholar
- 8.Chen LF (1992) Fabrication and characterization of SiC-based fibers. Ph. D. thesis, Leeds University, EnglandGoogle Scholar
- 12.Fareed AS, Fang P, Koczak MJ, Ko FM (1987) Am Ceram Soc Bull 66:353Google Scholar