Three-dimensional-linked carbon fiber-carbon nanotube hybrid structure for enhancing thermal conductivity of silicon carbonitride matrix composites

In this paper, a novel three-dimensional-linked (3D-linked) carbon fiber-carbon nanotube (Cf-CNT) hybrid structure is presented to improve the through-thickness thermal properties of polymer derived silicon carbonitride matrix composites. Comparing with pristine plain woven carbon fiber, the pores in the criss-cross position are fully filled with carbon nanotubes (CNT) in the presented Cf-CNT hybrid structure. CNT can be integrated in between the plain woven carbon fibers and generate a 3D-linked Cf-CNT hybrid network structure. Thanks to the percolating network of CNT and the densification effect, the through-thickness thermal conductivity of the resultant ceramic matrix composites is improved significantly, which is enhanced by 10% with short CNT and by 31% with long CNT, respectively. The thermal conductivity is found to increase with temperature from 100 to 900 °C for these composites. Multiphysics simulation is conducted to reveal the effects of the 3D-linked Cf-CNT hybrid structure on the thermal conductivity at various temperatures, which are consistent with experimental results.