Mechanism of retaining graphite phase in the graphite/SiC composite by condense layer with fine SiC grain reaction formed via nano carbon black

Abstract

For the reaction-formed graphite/SiC composites, the drastic consumption of vast amounts of carbon phase by violent reaction with liquid silicon is a prominent problem during reactive melt infiltration, resulting in low carbon content of the composites. To retain adequate graphite phase, in this work, hybrid carbon powders (PFC@G), adhered with nano carbon black via a binder, were employed as carbon sources for fabricating the graphite/SiC composites with high carbon content. The mechanism of retaining graphite phase in the graphite/SiC composites by reaction-formed SiC layer with nano carbon black was investigated. The results indicate that a carbon content of 43.03 vol% was obtained for graphite/SiC composites when the content of nano carbon black is 10 wt% in the carbon source. The microscopy results revealed that the PFC@G was protected effectively by the condense layer with fine SiC grains generated via the reaction between nano carbon black and liquid silicon.