Abstract
Most modern matrix composite materials employ a variety of carbon nanofillers to improve their mechanical, electrical, and functional properties. Nanofillers are separately implanted into the initial ceramic matrix, which complicates the composite manufacturing technology and increases the final cost. In this work, the synthesis of nanocarbon fillers was carried out using high-temperature (1200 degrees C) pyrolysis of phenolic resin directly inside the silicon carbide matrix. This results in the formation of a continuous 3D nanocarbon mesh uniformly binding and reinforcing the final product throughout the volume. The nanocarbon filler synthesized in the SiC matrix contains two allotropic carbon forms: nanographite and nanofibers. The study of the features of the carbon structure and morphology showed that during the pyrolysis the multilayered nanographite structures had been formed on the surface of SiC grains of average crystallite size equal to 20-35 nm. In the matrix pores, carbon nanofibers a few micrometers in length and 20-40 nanometers in diameter are synthesized. The reiteration of the phenolic resin impregnation-pyrolysis cycle increased the free carbon content from 4 to 7 wt.% for once and twice impregnated and pyrolyzed samples, respectively, and the Young's modulus, from 50.7 to 94.3 GPa. The obtained carbon content and structure are appropriate to produce C/SiC composite for application of ceramics and electrodes.