Preparation and thermal conductivity of CNTs/SiC nanocomposite film

The good high-temperature tolerance of SiC allows its use as thermal protection systems under severe conditions. Critical to the success is the effective heat transfer through a material to allow for effective cooling, however, the relative low thermal conductivity of SiC limited its application. The Carbon nanotubes (CNTs) are expected to be very good thermal conductors along the axis direction. Buckypaper was used as the preform, the CNTs/SiC nanocomposite film with a density of 1.66 g/cm³ and an open porosity of 15.9% was prepared by phenolic resin infiltration-pyrolysis and liquid silicon infiltration (LSI). CNTs were well filled within the SiC matrix and enwrapped by SiC matrix. The specific heat of this nanocomposite film was increased with the increasing temperature and reached a maximum of 3.11 Jg^-1 k^-1 at 1400 °C. The thermal conductivity perpendicular to the film surface reached a maximum close to 20 Wm^-1 K^-1 in the temperature range of 600∼1400 °C.