氧气辅助法制备氮化硼纳米管

将无定形硼粉于流动氨气(50 mL/min)和不同氧气流量(10、15、20、40 mL/min)的混合气氛下高温(1300℃)处理后, 在不锈钢基片上收集到白色棉花状产物。研究结果表明, 微量的氧气可将硼粉氧化成气态的B₂O₂中间体, 为BN纳米管的生长提供活性较高的硼源。当氧气流量适中时, 所得纳米管的平均直径为80 nm, 长度可达几百微米。氧气流量对BN纳米管的直径和产量影响较大, 纳米管直径随着氧气流量的增大而增大, 产量则出现先升高后降低的趋势。氮化硼纳米管的生长机理属于气-液-固模型。

Oxygen Gas-assisted Synthesis of Boron Nitride Nanotubes

Wool-like products were fabricated on the stainless-steel substrates by directly heating amorphous B powder at high temperature (1300℃) at 50 mL/min ammonia gas with different flow of oxygen gas (10, 15, 20, 40 mL/min). It was found that B powder could be oxidized by trace oxygen gas to form the intermediate B₂O₂ vapor, which can act as highly active boron source for the growth of BN nanotubes. When an appropriate amount of oxygen was introduced, the obtained nanotubes had an average diameter of about 80 nm and the lengths of several hundred micrometer. Both the diameter and the yield of BN nanotubes could be influenced dramatically by the flow rate of oxygen. With the increase of oxygen flow, the diameter of nanotubes was gradually increased, and the yield of nanotubes was improved obviously at first and then turned down. The formation mechanism of these nanotubes is governed by a vapor-liquid- solid (VLS) growth model.