In situ synthesis of nano size silicon carbide and fabrication of C-SiC composites during the siliconization process of mesocarbon microbeads preforms

C-SiC composites with carbon-based mesocarbon microbeads (MCMBs) preforms are a new type of high-performance and high-temperature structural materials for aerospace applications. In the present study, MCMB-SiC composites were fabricated by liquid silicon infiltration (LSI). Physical and mechanical properties such as density, porosity and bending strength were measured before and after siliconization. The results show the C-SiC composites have excellent bending strength, density and porosity of 210 MPa, 2.41 g/cm(3) and 0.62%, respectively. The chemical analysis shows that the composite is composed of 89% SiC, 2% Si and 9% C. The microstructural results also show the existence of two different areas of SiC, one zone of coarse micron size SiC at SiC Si interface and the other zone consists of fine nano-SiC particles at SiC C interfaces. The formation mechanism governing the siliconization of porous MCMB preform was also investigated. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.