Synthesis of h-AIN nanowires via carbothermal reduction and nitridation method using acetylene black.

Using acetylene black as an assistant reagent in the ammonia atmosphere, one dimensional (1D) hexagonal single crystalline aluminum nitride (AIN) nanowires were successfully synthesized via carbothermal reduction and nitridation method. With smooth surface and uniform diameter, the wool-like product of AIN nanowires grow along [001] direction and are 80-120 nm in diameter and several tens micrometers in length. According to thermodynamic and kinetic analysis, AI2O3 initially was reduced to a volatile suboxide gas Al2O at 1800 degrees C. Then gaseous Al2O was transported by N2/NH3 mixtures to about 1200 degrees C, where 1D AIN nanowires formed by the reaction of Al2O gas, graphite and NH3. Due to high surface area, small particle size and amorphous structure, acetylene black maybe possess more active sites and more effective contact area, which benefits the first step reaction. The electrostatic polar charge model and crystallographic characteristics are employed to explain the growth mechanism of AIN nanowires. To our knowledge, acetylene black is the first time to be used for synthesizing 1D AIN nanostructures via carbothermal reduction and nitridation method, which would be an efficient, economical assistant reagent for fabricating nitride nanostructures.