The carbothermal reduction of SiO2 gel containing filter paper (as carbon precursors) in argon was used to prepare SiC nanowires and nanoparticles. The resulting SiC ceramic, as well as the conversion mechanism of carbon/silica composites to SiC nanowires and nanoparticles, have been investigated by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TG) techniques. XRD and IR studies show that the materials, obtained from reaction at 1550 degrees C for 1 h in static argon atmosphere, are beta-SiC. SEM and TEM reveal that SiC nanowires is single crystal wires with diameters ranging from 50-200 nm and their lengths over several tens of microns. According to thermodynamic analysis, SiC nanowires and SiC nanoparticles in the resulting SiC ceramic are formed by gas-gas reaction of SiO (g) and CO (g).