Centimeter-scale ultra-long SiC nanowires were successfully synthesized by a simple catalyst-free chemical vapor deposition at 1250-1300 degrees C. The synthesized SiC nanowires possess their lengths up to 10 millimeters and most of them are parallel to each other with uniform morphology and diameter. The core-shell structure of SiC nanowires is observed that the SiC crystal's core with diameter of 10 nm is coated by an amorphous layer with 20 nm thickness. The formation mechanism of the ultra-long nanowires could be mainly ascribed to the lower flow rate of reaction vapors, which made the high gas concentration and supersaturation conditions of reaction vapors come into being more easily. Both the low flow rate and the vapor-solid growth mechanism were responsible for the formation of the centimeter-scale ultra-long SiC nanowires. (C) 2011 Elsevier B.V. All rights reserved.