Microstructure and properties of reaction-formed SiC ceramic derived from mesocarbon microbeads

Reaction-formed SiC was fabricated by mesocarbon microbeads(MCMBs) and SiC powder through molding and Si infiltration.The changes of volume fractions of phases as functions of SiC powder content, silicinized temperature and holding time were calculated. Meanwhile, the properties were tested and the morphologies of surfaces were investigated by SEM. The calculated results show that volume fractions of Si and SiC phases increase with increasing SiC powder content, and that of C phase decreases; the open porosity decreased and density increases with increasing silicinized temperature, meanwhile the content of SiC phase clearly increases. The performance experimental results indicate that the samples have low electric resistivity (the lowest value of 0.36 μΩ·m) and high banding strength (the highest value of 359 MPa). The etched surfaces of SEM micrographs show that there are two sizes of SiC particles, indicating there existing different silicon/carbon reaction mechanisms.