F. Qian-Gang et al /Ceramics International 36(2010)1463-1466 Fig. 7. Fracture surface micrographs of the samples after flexural tests. (a)C/C and(b) HPRS-SiC coated C/C pyrocarbon evidently, which is advantageous to the ductility of Fund of State Key Laboratory of Solidification Processing the sample. From Fig. 7(b), the HPRS-SiC coated C/C sample (NWPU), China( Grant No. KP200913) had an even fracture surface. accordant with its brittle fracture characteristic. It is well-known that defects. such as holes and References cracks, are generally existent at the interface between carbon fiber and carbon matrix. By HPRS-SiC coating, these defects [11 N.S.Jacobson, D.M. Curry, Oxidation microstructure studies of reinforced will be eliminated partially, and the interface bonding between carbon/carbon, Carbon 44(2006)1142-1 150 ber and matrix will be improved largely. Therefore, the [2] J.F. Huang, H.J. Li, X.B. Xiong, X.R. Zeng K.Z. Li, YWFu, Progress on the oxidation protective coating of carbon-carbon composites, New fracture mode of the C/C sample changed from a pseudo-plastic Carbon Materials 20(2005)373-379 fracture behavior to a brittle one after being coated with a [3] W.M. Lu, DD L Chung, Oxidation protection of carbon materials by acid HPRS-SiC coating 4. Conclusions W hosphate impregnation, Carbon 40(2002)1249-12<>y/ Surface and tion through coating cracks of SiC-protected carbon/carb Coatings Technology 203(2008)372-383 [5 J.F. Huang, X.R. Zeng. H. Li, X.B. Xiong. Y.w. Fu, Influence of the HPRS technique can be applied to obtain a dense and crack- preparation are on the phase, microstructure and anti-oxidation free SiC coating for C/C composites. The HPRS-SiC coating es, Carbon42(2004)1517-1521 can infiltrate into C/C substrate deeply, resulting in excellent [6] C.A. A Cairo, M.L.A. Graca, C.R.M. Silva,JC.Bressiani,Functionally thermal shock and oxidation resistance between 1773 K and radient ceramic coating for C-C antioxidation protection, Journal of the European Ceramic Society 21(2001)325-329 room temperature. The flexural property of the HPRS-SiC [7) B Wang, K.Z. Li, H.J. Li, Q.G. Fu, X Wang, Sic coating prepared by a coated C/C sample is higher than those of the bare C/C and the ique of pack cementation and CVD on carbon/carbor PRS-SiC coated C/C sample. The fracture mode of the C/C posites, Journal of Inorganic Materials 22(2007)737-741 ample changes from a pseudo-plastic behavior to a brittle one [8] S. Lloyd. N. Avery, M. Pal, A novel laser technique for oxidation-resistar after being coated with a HPrs-Sic coating ting of carbon-carbon composite, Carbon 39(2001)991-999 [9 Q.G. Fu, H.. Li, X.H. Shi, K.Z. Li, G D. Sun, Silicon carbide coating to protect carbon/carbon composites against oxidation, Scripta Materialia 52 Acknowledgements 2005)923-927 [10] D. Veljovic. B Jokic, R. Petrovic, E. Palcevskis, A. Dindune, I.N. Mihai This work has been supported by the National Natural escu,D. Janackovic, Processing of dense nanostructured HAP ceramics by Science Foundation of China under Grant No. 50802075 and nd hot pressing, Ceramics International 35(2009)1407-1413 [11 LJ. Huang, L Geng, A B. Li, F.Y. Yang, H.X. Peng, In situ TiBw/Ti-6Al- the""Project under Grant No. 08040, and supported by 4V composites with novel reinforcement architecture fabricated by rea NPU Foundation for Fundamental Research and the Research tion hot pressing, Scripta Materialia 60(2009)996-999pyrocarbon evidently, which is advantageous to the ductility of the sample. From Fig. 7(b), the HPRS-SiC coated C/C sample had an even fracture surface, accordant with its brittle fracture characteristic. It is well-known that, defects, such as holes and cracks, are generally existent at the interface between carbon fiber and carbon matrix. By HPRS-SiC coating, these defects will be eliminated partially, and the interface bonding between fiber and matrix will be improved largely. Therefore, the fracture mode of the C/C sample changed from a pseudo-plastic fracture behavior to a brittle one after being coated with a HPRS-SiC coating. 4. Conclusions HPRS technique can be applied to obtain a dense and crack￾free SiC coating for C/C composites. The HPRS-SiC coating can infiltrate into C/C substrate deeply, resulting in excellent thermal shock and oxidation resistance between 1773 K and room temperature. The flexural property of the HPRS-SiC coated C/C sample is higher than those of the bare C/C and the PRS-SiC coated C/C sample. The fracture mode of the C/C sample changes from a pseudo-plastic behavior to a brittle one after being coated with a HPRS-SiC coating. Acknowledgements This work has been supported by the National Natural Science Foundation of China under Grant No. 50802075, and the ‘‘111’’ Project under Grant No.08040, and supported by NPU Foundation for Fundamental Research and the Research Fund of State Key Laboratory of Solidification Processing (NWPU), China (Grant No. KP200913). References [1] N.S. Jacobson, D.M. Curry, Oxidation microstructure studies of reinforced carbon/carbon, Carbon 44 (2006) 1142–1150. [2] J.F. Huang, H.J. Li, X.B. Xiong, X.R. Zeng, K.Z. Li, Y.W. Fu, Progress on the oxidation protective coating of carbon-carbon composites, New Carbon Materials 20 (2005) 373–379. [3] W.M. Lu, D.D.L. Chung, Oxidation protection of carbon materials by acid phosphate impregnation, Carbon 40 (2002) 1249–1254. [4] N.S. Jacobson, D.J. Roth, R.W. Rauser, J.D. Cawley, D.M. Curry, Oxida￾tion through coating cracks of SiC-protected carbon/carbon, Surface and Coatings Technology 203 (2008) 372–383. [5] J.F. Huang, X.R. Zeng, H.J. Li, X.B. Xiong, Y.W. Fu, Influence of the preparation temperature on the phase, microstructure and anti-oxidation property of a SiC coating for C/C composites, Carbon 42 (2004) 1517–1521. [6] C.A.A Cairo, M.L.A. Graca, C.R.M. Silva, J.C. Bressiani, Functionally gradient ceramic coating for C–C antioxidation protection, Journal of the European Ceramic Society 21 (2001) 325–329. [7] B. Wang, K.Z. Li, H.J. Li, Q.G. Fu, X. Wang, SiC coating prepared by a two-step technique of pack cementation and CVD on carbon/carbon composites, Journal of Inorganic Materials 22 (2007) 737–741. [8] S. Lloyd, N. Avery, M. Pal, A novel laser technique for oxidation-resistant coating of carbon–carbon composite, Carbon 39 (2001) 991–999. [9] Q.G. Fu, H.J. Li, X.H. Shi, K.Z. Li, G.D. Sun, Silicon carbide coating to protect carbon/carbon composites against oxidation, Scripta Materialia 52 (2005) 923–927. [10] D. Veljovic, B. Jokic, R. Petrovic, E. Palcevskis, A. Dindune, I.N. Mihai￾lescu, D. Janackovic, Processing of dense nanostructured HAP ceramics by sintering and hot pressing, Ceramics International 35 (2009) 1407–1413. [11] L.J. Huang, L. Geng, A.B. Li, F.Y. Yang, H.X. Peng, In situ TiBw/Ti–6Al– 4V composites with novel reinforcement architecture fabricated by reac￾tion hot pressing, Scripta Materialia 60 (2009) 996–999. Fig. 7. Fracture surface micrographs of the samples after flexural tests. (a) C/C and (b) HPRS-SiC coated C/C. 1466 F. Qian-Gang et al. / Ceramics International 36 (2010) 1463–1466