Journal of Inorganic Materials

• Research Paper • Previous Articles     Next Articles

SiC Coating Prepared by a Two-step Technique of Pack Cementation and CVD on Carbon/Carbon Composites

WANG Biao, LI Ke-Zhi, LI He-Jun, FU Qian-Gang, WANG Xiang, LAN Feng-Tao   

  1. School of Materials Science, Northwestern Polytechnical University, Xi’an 710072, China
  • Received:2006-08-11 Revised:2006-10-17 Published:2007-07-20 Online:2007-07-20

Abstract: A SiC coating was prepared on carbon/carbon (C/C) composites by a two-step technique of pack cementation and CVD processes to prevent these composites from oxidation. SEM, EDS and XRD were applied to analyze the surface and cross-section morphologies, element distribution and phase composition of the coating, respectively. The results show that a transitional layer with gradient distribution of Si and C content is formed between the SiC coating obtained by pack cementation process and C/C substrate, and the compact coating prepared by CVD process effectively fills the pores of the coating by pack cementation. The coating made by the two-step technique exhibits excellent oxidation protective ability. The weight loss percentage of the coated C/C composites is only 2.01% after oxidation in air at 1500℃ for 60h. The weight loss of C/C composites is primarily due to the reaction of C/C and oxygen diffusing through the microcracks in the coating during the thermal cycle between 1500℃ and room temperature.

Key words: carbon/carbon composites, chemical vapor deposition, coating

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