Abstract:
The present study investigates the effect of additional carbon source, in the form of carbon nanotubes (CNTs), on mechanical and thermal properties of carbon fiber reinforced silicon carbide (C/C-SiC) ceramic matrix composites (CMC) produced by liquid silicon infiltration (LSI) technique. The CNTs used in this study were impregnated into the C/C preforms before the liquid silicon infiltration stage. The results showed that the addition of excess carbon to the C/C preforms in the form of CNTs enhanced Si infiltration efficiency significantly resulting in C/C-SiC composites with higher density and microstructural uniformity. Accordingly, the addition of CNTs improved the flexural strength of the composites by 40% with respect to no-CNT-containing composites due to a lower amount of residual porosity and additional reinforcement effect of the unreacted CNTs. The thermal conductivity of the resulting C/C-SiC composites has been also increased by 31% and 18% parallel and perpendicular to the carbon fiber-woven fabric surface, respectively, by CNT addition.Graphical abstract