Papers by Keyword: Silicon Carbide Fiber

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Authors: Zeng Yong Chu, Yan Dong Wang, C.X. Feng, Yong Cai Song, Jun Wang, J.Y. Xiao, X.D. Li
651
Authors: Dong Geun Shin, Doh Hyung Riu, Hyung Rae Kim, Y. Kim, Young Keun Jeong, Hong Sik Park, Hyoun Ee Kim
91
Authors: Zeng Yong Chu, Hai Feng Cheng, J. Wang, Yong Cai Song, Yan Dong Wang, C.X. Feng
Abstract: Microflaws were detected on the cross-section of polymer-derived silicon carbide fibers and their formation mechanism was studied by varying the curing degree and the firing rate. The results show that microflaws decrease in size with increase of the curing degree due to an increased ceramic residue. The results also show that microflaws decrease in size with decrease of the firing rate. No microflaws are detectable when the firing rate is as low as 10K/h. This indicates that the microflaws are the main channels of evolution gases and the pressure of these gases leads to their formation and propagation. So a high curing degree and a low firing rate are both preferred in the preparation of dense silicon carbide fibers.
1297
Authors: M. Holmquist, Annika Kristoffersson, R. Lundberg, J. Adlerborn
239
Authors: Natalia I. Baklanova, B.N. Zaitsev, Anatoly Titov
Abstract: CMC's reinforced by SiC-based fibers achieve high toughness and damage tolerance through the disposal of weak fiber coating which can deflect cracks and promote debonding at the fiber/matrix region. Refractory oxide-based systems are considered as the most promising ones for this purpose. Sols of zirconia, including stabilized zirconia were used as simple and readily processable precursors for obtaining interfacial coatings on SiC tow and cloth. The morphology, composition, topography, roughness, tensile properties of as-prepared and exposed to air at 1000°C coated fibers were evaluated by SEM/EDS, XPS, XRD, AFM, micro Raman analysis. The peculiarities of the behavior of oxide-coated fibers are governed by the properties of initial sols, procedure for coating fabrication, chemical and nanostructural factors. The peculiarities of the behavior of the stabilized zirconia interphase with accurate phase control will be discussed. A monitoring of the t→ m phase transformation within ZrO2 interfacial coating on SiC fiber using micro Raman makes it possible quantitatively to evaluate an ability of ZrO2 as oxidation resistance and readily deformable weak interfacial coating for the next-generation CMC's.
51
Authors: Zeng Yong Chu, Rong An He, Xiao Dong Li, Hai Feng Cheng, Jun Wang
Abstract: In the preparation of polymer-derived SiC fibers, nanochannels are believed to be formed in the early pyrolysis stages due to loss of large volumes of pyrolysis gases. In this paper, small angle X-ray scattering (SAXS) was applied to the characterization and calculation of nanochannels in partiallypyrolyzed SiC fibers. The SAXS measurements showed that nanochannels with a radius of 1.0-20 nm were formed for fibers heat-treated at 973K and 1173K. But their distributions were not continuous and at lower part of the distribution, a peak value was observed at about 1.2nm. This means if the nanochannels are finely controlled, the partially-pyrolyzed SiC fibers have great potential application in the fields of hydrogen storage, gas separation, and so on.
1301
Authors: Akira Idesaki, Masaki Narisawa, Kiyohito Okamura, Masaki Sugimoto, Y. Morita, T. Seguchi, M. Itoh
39
Authors: Xin Xing, Lin Liu, Feng Cao, Xiao Dong Li, Zeng Yong Chu, Hai Feng Cheng
Abstract: A melt-spinnable precursor for SiC based fibers was prepared from blend polymers of polycarbosilane (PCS) and modified polymethylsilane (M-PMS). The blend polymers cured at 320°C are different from M-PMS and PCS. The ceramic yield of these blend polymers is about 83%. The C/Si ratio of M-PMS/PCS derived ceramics (pyrolyzed at 1250°C) is linear to the content of MPMS in M-PMS/PCS. After melt spinning, thermal oxidation curing, and pyrolysis, Si-C-O fibers were obtained. The diameter and the tensile strength of the resulted fibers are 16.5μm and 1.62GPa, respectively.
139
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