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

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.

Automated summary

In this study, hybrid carbon powders (PFC@G) adhered with nano carbon black were used as carbon sources to fabricate graphite/SiC composites with a high carbon content. The retention mechanism of the graphite phase was investigated, and it was found that the reaction-formed SiC layer with nano carbon black effectively protected the graphite phase.