Low-Energy Ablation and Low Thermal Diffusivity of a CFRC Composite Modified by SiC

Abstract

The use of materials for aerospace devices, such as rocket nozzles and thermal shields, depends primarily on their thermal and structural characteristics. Ceramic materials and carbon composites have been studied for this purpose. This work measures and investigates the ablation and thermal diffusivity of hybrid matrix composites of carbon–silicon carbide matrix reinforced by carbon fiber (C/C-SiC). Silicon powder was added to a phenolic thermoset matrix with proportions of 5, 10, and 20 %. In addition, the liquid polymer infiltration (LPI) process using a silicone polymer was used to produce the same composites. A thermal plasma torch was used to obtain the ablation and effective thermal diffusivity characteristics of the materials. The morphologies, microstructures, and chemical compositions of the samples were investigated by scanning electron microscopy and energy-dispersive spectrometry (SEM/EDS) and X-ray diffraction (XRD). The thermal diffusivities of the composites were found to be in the range of 0.2–1.5 × 10−6 m2·s−1 from 700 °C to 1000 °C, respectively. The void volume fraction of the composites was approximately 20 % and decreased the thermal diffusivity.