Polycarbosilane as a modulator for reaction-bonded silicon carbide processing of GNPs/Si mixtures

When graphene is used to enhance reaction-bonded silicon carbide (RBSC), the problem of graphene being corroded by molten silicon should be considered. In this work, the polycarbosilane (PCS) was uniformly adhered to the surface of graphene nanoplatelets (GNPs) by the sol–gel method, and SiC barrier formed after pyrolysis. The structural evolution of GNPs in reaction sintering and the chemical structure of GNPs-PCS were investigated. The results showed that GNPs after siliconizing showed a porous structure, consisting of nanometer SiC particles on the surface. The ceramic yield and final pyrolysis temperature of PCS were reduced after mixing with GNPs and divinylbenzene (DVB). The SiC formed by the pyrolysis of PCS was uniformly distributed among GNPs. SiC whiskers (SiC w ) were observed in the sample of GNPs and GNPs-PCS after siliconizing. The difference and formation mechanism of SiC w in these two samples were discussed. After PCS modification and pyrolysis, GNPs survived in the loss on ignition experiment. The prepared composite powder further improved the toughness of GNPs/RBSC by 14.69%.