MCMB-SiC composites; new class high-temperature structural materials for aerospace applications

Graphite-silicon carbide (G-SiC), carbon/carbon silicon carbide (C/C-SiC) and mesocarbon microbeads-silicon carbide (MCMB-SiC) composites were produced using liquid silicon infiltration (LSI) method and their physical and mechanical properties, including density, porosity, flexural strength and ablation resistance were investigated. In comparison with G-SiC and C/C-SiC composites, MCMB-SiC composites have the highest bending strength (210 MPa) and ablation resistance (9.1%). Moreover, scanning electron microscopy (SEM) and optical microscopy (OM) are used to analyze the reacted microstructure, pore morphology and pore distribution of carbon-based matrices. As a result, SiC network reinforcement was formed in situ via a reaction between liquid silicon and carbon. The unreacted carbon and solidified silicon are two phases present in the final microstructure and are characterized by X-ray diffraction (XRD). Based on the results obtained and the low-cost processing of pitch-based materials, the MCMB-SiC composite is a promising candidate for aerospace applications. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.