Fabrication and Characterization of SiC-coated Multi-Walled Carbon Nanotubes Reinforced Reaction Bonded SiC Composite

摘要

SiC-coated multi-walled carbon nanotubes (SiC-coated MWNTs) made by RF magnetron sputtering were introduced into the SiC suspensions to enhance the mechanical behaviors of reaction bonded silicon carbide ceramics. The composites were prepared by the epoxy resin curing and liquid silicon infiltration at 1550°C for 60min. The distribution, morphology, and reinforcing behaviors of MWNTs were investigated. X-ray diffraction (XRD) reveals that the MWNTs were reserved during the reaction sintering. The flexural strength and fracture toughness increase with MWNTs ranging from 0wt% to 0.5wt%, reaching the peaks value of 347MPa and 4.3MPam~(1/2) respectively at the MWNTs fraction of 0.5 wt%. This improvement derives from the MWNTs pullout. The consequent decline at MWNTs fraction of 1wt% is resulted from the corrosion of agglomerated MWNTs and the increase of residual silicon.