Thermal and mechanical properties of SiC/SiC-CNTs composites fabricated by CVI combined with electrophoretic deposition

In order to improve the thermal and mechanical properties, CNTs were introduced into the matrix of SiC/SiC composites through electrophoretic deposition. Effect of the introduction of CNTs into CVI SiC/SiC composites was investigated. Microstructure, mechanical properties and thermal conductivity of SiC/SiC composites (SS) and SiC/SiC-CNTs composites (SSCS) were compared. Results indicated that matrix of SSCS presented a multi-layer morphology while that of SS showed a single-layer of SiC. Compared with SS, intra-bundle pores in SSCS were much smaller and fewer, which was accorded with the higher density (2.78±0.04 g/cm3) and smaller porosity (5.8±0.3%). SSCS had a better performance in bending strength (484±16 MPa) and damage tolerance (19.4±0.7 MPa m1/2) because of the pull out and crack bridging of CNTs. The thermal conductivity of SSCS was 1.74 times higher than that of SS. With the introduction of CNTs into CVI SiC/SiC composites, density, bending strength, damage tolerance and thermal conductivity were improved.