Long β-Silicon Carbide Necklace-Like Whiskers Prepared by Carbothermal Reduction of Wood Flour/Silica/Phenolic Composite

Long silicon carbide (SiC) microwhiskers with a necklace-like morphology have been successfully synthesized by a carbothermal reduction process without using any catalyst. In the process, the wood flour/silica (SiO(2))/phenolic composite was chosen as both silicon and carbon sources. The morphology and structure were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). Studies found that the as-synthesized whiskers were grown as single crystalline beta-SiC along the (111) direction with the length up to hundreds of micrometers. The whiskers consisted of beta-SiC strings with diameters of 1-2 mu m and periodic beta-SiC beads with diameters of 3-5 mu m. On the basis of characterization results, a growth mechanism is proposed to clarify the formation of necklace-like whiskers.