Papers by Keyword: C/C Composite

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Authors: Yan Bo Liu, Quan Sheng Wang, Kang Zhi Ma, Jun Liang Liu, Si Hao Wei, Wen Chao Fan
Abstract: Carbon fiber reinforced carbon matrix composites (C/C) have received much attention due to their excellent high-temperature strength, high thermal conductivity, low coefficient of thermal expansion (CTE), good thermal shock resistance. However, the poor ablation resistance of the C/C restricts its high temperature ablating applications. Making a thin anti-ablation coating on the C/C has been proved to improve the performance effectively. In order to improve the anti-ablation property of the composite, MoSi2 coatings were deposited by Atmosphere Plasma Spraying (APS) on the SiC covered C/C matrix. The SiC coatings were prepared by pack cementation. Oxyacetylene flame torch was selected to simulate the ablation situation. The ablation temperature was 1800°C. XRD and SEM were employed to discover the diversification of the coatings structure and composition. And the mechanism of anti-ablation of the MoSi2 coatings system was investigated in this paper.
Authors: Tsuyoshi Aoki, Hidenori Hatta, Koji Goto, H. Fukuda
Authors: Wen Dong Yang, Jian Feng Huang, Li Yun Cao, Xie Rong Zeng
Abstract: Cristobalite aluminum phosphate (C-AlPO4) coatings were prepared by hydrothermal electrophoretic process on SiC coated C/C composites at different temperatures. The as-prepared C-AlPO4 coatings was characterized by SEM analyses. The influence of hydrothermal deposition temperature on the microstructures of the as-prepared coatings and the deposition kinetics mechanism were investigated. Results show that dense and homogeneous C-AlPO4 coatings on SiC coated C/C composites can be achieved at 373K and 220V deposition voltage; Kinetics investigations show that the deposition process of the C-AlPO4 coatings on SiC coated C/C composite is controlled by the diffusion rate of the charged C-AlPO4 particles to the cathode; the deposition rate increases with the increase of hydrothermal temperature. The diffusion equation and the kinetic expression of coating process follow the Fick’s second law and Ahrennius relationship. The deposition activation energy of the C-AlPO4 coatings fabricated by the hydrothermal electrophoretic process is calculated to be 21.88kJ/mol.
Authors: Jae Ho Jeon, Hai Tao Fang, Zhong Hong Lai, Zhong Da Yin
Abstract: The concept of functionally graded materials (FGMs) was originated in the research field of thermal barrier coatings. Continuous changes in the composition, grain size, porosity, etc., of these materials result in gradients in such properties as mechanical strength and thermal conductivity. In recent years, functionally graded structural composite materials have received increased attention as promising candidate materials to exhibit better mechanical and functional properties than homogeneous materials or simple composite materials. Therefore the research area of FGMs has been expending in the development of various structural and functional materials, such as cutting tools, photonic crystals, dielectric and piezoelectric ceramics, thermoelectric semiconductors, and biomaterials. We have developed functionally graded structural ceramic/metal composite materials for relaxation of thermal stress, functionally graded anti-oxidation coatings for carbon/carbon composites, and functionally graded dielectric ceramic composites to develop advanced dielectric ceramics with flat characteristics of dielectric constant in a wide temperature range. This paper introduces functionally graded coatings for C/C composites with superior oxidation resistance at high temperatures.
Authors: Hua Liang Liu, Xiu Jun Liu, Zhi Jun Qiao, Tong Qi Li, Zi Jun Hu
Abstract: C/C composites were prepared by low temperature and hot pressure moulding process from T300 carbon fibre and medium temperature pitch(MTP) or MP with nematic liquid crystalline. The effect of the content of carbon fibre and different proportion of MTP to MP on interlaminar bonding strength (ILBS) of C/C composites was investigated. C/C composites were characterized by ILBS test and scanning electron microscope. Results showed that the ILBS increased with the increase of the content of carbon fibre and proportion of MTP. When the content of carbon fibre was 60.5%, the ILBS of composites prepared from MP reached up to 1.498MPa, and to 3.031MPa from MTP.
Authors: J. W. Ren, Rui Cheng Bai, H. Li, Ai Jun Li, M. S. Ren, Jin Liang Sun
Abstract: The effect of DLC film on tribological properties of C/C composites was investigated with a ball-on-disk tribometer in dry air, compared with the result of specimen without DLC film. The DLC film was prepared on the surface of C/C composites substrate by plasma enhanced chemical vapor deposition method (PECVD). After PECVD, structural characterization of the film, adhesion strength of film to substrate, surface morphology and linear wear were studied by Raman spectroscopy, Rockwell-C apparatus, Scanning Electron Microscopy (SEM) and Optical Microscopy (OM), respectively. The result showed that the film deposited on the surface of C/C substrate exhibited typical Raman spectroscopy fingerprints of DLC films and a good adhesion to the substrate surface was found. A stable friction coefficient was observed during the friction tests. With the DLC film, the friction and wear properties of C/C composites were improved significantly. The average friction coefficient of the C/C specimen with DLC film (0.08637) was reduced by 65.56% than that of the one without DLC film (0.2508) and the linear wear was decreased by 84.7% ( from 148.47μm to 22.71 μm) as well.
Authors: Dong Su Bae, Dong Young Son, Sang Ll Lee, Hong Sik Park, Kwang Soo Kim, Jae Ho Jeon
Abstract: Four kinds of raw C/C composites with a density between 1.25~1.66g/㎤ were used in order to investigate the effect of the initial porosity of C/C composites on mechanical properties of liquid silicon infiltrated C/SiC composites. The microstructure observation, image analysis and flexural strength test of the composites were performed. The density and microstructural changes with the variation of the initial porosity was discussed in the terms of the infiltration behavior of liquid silicon and the reaction between liquid silicon and matrix carbon.
Authors: Xiao Hu Zhang, He Jun Li, Zhi Biao Hao, Hong Cui
Abstract: The influence of needling parameters on mechanical properties of carbon-carbon (C-C)composites reinforced by needled carbon cloth was studied in the present investigation. The results showed that needling density (ND)and needle-punching depth (PD) both had a larger effect on interlaminar shear strength (ILSS) than on compression strength and flexible strength of Needling C-C(NC-C). The mechanical properties of NC-C increased with increasing punching density in the range of 20-45 punch/cm2 and also with increasing punching depth range from10 to16mm. The NC-C with the highest ND value of 55punch/cm2 had highest ILSS value of 27 MPa.The optimized ND and PD parameters was 30 punch/cm2 and 12mm respectively, which resulted in a high value of tensile strength(119MPa), bending strength (220MPa) and compression strength (235 MPa) in the X-Y direction .
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