Synthesis of "a β-SiC nanorod within a SiO2 nanorod" one dimensional composite nanostructures

A beta-SiC nanorod within a SiO2 nanorod one dimensional composite nanostructures were synthesized by the combination of a low temperature (1650 degrees C) carbothermal reduction and a high temperature (1800 degrees C) heating of sol-gel derived silica xerogels containing carbon nanoparticles. The composite nanostructures are more than 20 mu m in length. The diameters of the center thinner beta-SiC nanorods are typically in the range 10-30 nm, while the outside diameters of the corresponding thicker amorphous SiO2 nanorods are between 20 and 70 nm. Large quantities of SiC rod nuclei and the nanometer-sized nucleus sites on carbon nanoparticles are both favorable to the formation of much thinner beta-SiC nanorods. The formation of the outer coaxial thicker amorphous SiO2 nanorods is from the combination reaction of decomposed SiO vapor and O-2 during cooling. (C) 1998 Published by Elsevier Science Ltd.