Aluminum borate (Al4B2O9) nanowires are synthesized by directly heating a mixture of Al and B2O3 powder at 850 degreesC. The nanowires synthesized are single-crystal with lengths about several micrometers and diameters ranging from 20 to 100 nm. The transmission electron microscopy (TEM) images show that Al particles are at the tips of some nanowires, which indicates a vapor liquid-solid (VLS) growth mechanism. Boron oxide dissociates metal Al powder to prevent it from aggregating and simultaneously reacts with aluminum to produce aluminum borate. A self-catalytic growth mechanism of the aluminum borate nanowires is proposed. (C) 2003 Elsevier Science B.V. All rights reserved.