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通过烧成制备电阻率不同的4种SiC纤维,并对纤维的元素组成、结晶性能和表面结构进行分析。结果表明:通过调整不熔化及烧成工艺参数可以获得电阻率量级不同的SiC纤维。当纤维表层具有一定厚度的高富碳层结构时,纤维的电阻率受整体自由碳含量与结晶性能的影响不显著,此时,纤维具有较低的电阻率。富碳层的产生与不熔化纤维烧成时分解产生的烃类小分子的重新裂解沉积有关。通过低温氧化除去纤维表面的富碳层可以使纤维的电阻率增大。表面结构对连续SiC纤维的电阻率有重要影响。
Four kinds of SiC fibers with different resistivities were prepared by calcining, and the elemental composition, crystallinity and surface structure of the fibers were analyzed. The results show that SiC fibers with different resistivity can be obtained by adjusting the parameters of non-melting and sintering. When the fiber surface has a certain thickness of the carbon-rich layer structure, the electrical resistivity of the fiber is not significantly affected by the overall free carbon content and the crystallinity. In this case, the fiber has a lower resistivity. The production of a carbon-rich layer is related to the re-cracking of small hydrocarbon molecules produced by the decomposition of the un-melted fiber. The carbon-rich layer on the fiber surface can be oxidized by low temperature oxidation to increase the resistivity of the fiber. The surface structure has an important effect on the resistivity of continuous SiC fibers.