SiC coating toughened by SiC nanowires to protect C/C composites against oxidation

A dense SiC coating toughened by SiC nanowires was prepared on carbon/carbon (C/C) composites using a two-step technique of chemical vapor deposition (CVD) to protect them against oxidation. The morphologies and crystalline structures of the coatings were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. SiC nanowires played a role in decreasing the size of the cracks and improving the thermal shock resistance of the coating. The result of thermal shock between 1773 K and room temperature for 21 times indicates that, compared with the SiC coating without SiC nanowires, the average size of the cracks in the SiC coating toughened with SiC nanowires reduced from 5 +/- 0.5 to 3 +/- 0.5 mu m. The weight loss of the SiC coated C/C composites decreased from 9.32 to 4.45% by the introduction of SiC nanowires. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.