Rapid carbothermal synthesis of nanostructured silicon carbide particles and whiskers from rice husk by microwave heating method

This paper reported a simple and rapid route to large-scale synthesis of nanostructured SiC powders using rice husk as the precursor. Rapid carbothermal reduction reactions were achieved in a 2.45 GHz microwave field in an argon atmosphere. The XRD patterns revealed that complete carbothermal reduction of silica was achieved at 1300 °C for 60 min or at 1500 °C for only 15 min by microwave heating, resulting in β-SiC formation. The FE-SEM images showed that the β-SiC powders were mixtures of particles and whiskers. The β-SiC particles had diameters of 60–130 nm and the β-SiC whiskers, which were several to tens of micrometers in length, had diameters of 110–170 nm. The β-SiC powder synthesized at 1500 °C for 15 min showed the highest BET surface area of 12.2 m2/g. Compared to the conventional heating method, the microwave heating method proved to be an efficient approach for synthesis of SiC in terms of energy and time saving, as well as for fabrication of nanostructured SiC.

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► Nanostructured β-SiC powders were synthesized from rice husk by microwave heating.
► The effects of reaction temperatures and times were investigated.
► Microwave heating is more energy and time saving than conventional heating.
► Microwave heating is favorable to synthesis of nanostructured β-SiC.