Controllable synthesis of chain-bead SiC whiskers from rice husk powders via molten-salt method

In view of the current situation that morphology of SiC whiskers synthesized from rice husk is too single, in this work, the chain-bead SiC whiskers were successfully synthesized via a simple molten-salt method. The effects of heating temperature on the phase composition and morphology of the product were compared under the salt-free and molten-salt conditions. The results indicated that the liquid environment formed by molten salt could retain SiO 2 in the product and promote the formation of cristobalite, inhibiting the formation of SiC. Compared with the SiC synthesized under salt-free condition (linear morphology), the SiC whiskers synthesized by the molten-salt method at 1400 °C showed a chain-bead morphology, which was composed of β-SiC stalks and round beads of amorphous SiO 2 on the stalks. Finally, the formation mechanism of chain-bead SiC whiskers in the molten-salt environment was clarified.