Microstructure and mechanical properties of SiC nanowires reinforced hydroxyapatite coating on carbon/carbon composites

In order to improve the cohesion strength of hydroxyapatite (HA) coating on carbon/carbon composites, SiC nanowires were introduced as reinforcement material in the coating. The results showed that the coating reinforced by SiC nanowires consisted of flake-like crystals with non-uniform grain size and plate-like crystals. The flake-like crystals were embedded in the plate-like crystals to form an interlocking structure. The thickness of the coating with SiC naowires was 80 mu m, thicker than 25 mu m without SiC nanowires. Moreover, in the inner layer of coating, HA crystals distributed uniformly in the SiC nanowires which formed a three-dimensional framework structure. Tensile bond test shows that the average tensile strength of the coatings can be increased from 3.96 +/- 0.34 to 8.05 +/- 0.41 MPa after introducing SiC nanowires. The porous SiC nanowires could form pinning effect at the coating/matrix interface to improve the interface bond, and provide a three-dimensional framework structure in the deposition process to improve the cohesion of HA coating. (c) 2012 Elsevier B.V. All rights reserved.