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研究了纳米铁填充的碳纳米管基复合纤维在空气中的热氧化性能。结果表明:一般在室温即被氧化的铁(Fe)纳米粒子在170℃仍然具有良好的稳定性。这一方面是由于碳纳米管的保护作用所致,另一方面碳纳米管末端的Fe纳米粒子在室温下即迅速被氧化成反尖晶石型Fe3O4/γ-Fe2O3,170℃以下能有效阻止氧分子向碳纳米管内扩散。因此,170℃可以被看作氧分子扩散进入碳纳米管腔的极限温度。在170℃以下时,氧分子无法渗透Fe3O4/γ-Fe2O3晶格在管腔中形成氧分子。当温度高于170℃时,氧分子渗透发生,管腔内的Fe纳米粒子由靠近管末端位置到内部逐渐被氧化。由于相对良好的热氧化稳定性,Fe填充碳纳米管基复合纤维的铁磁性将可以在更高温度范围内得以保持。
The thermal oxidation properties of nano-iron-filled carbon nanotube-based composite fibers in air were studied. The results show that iron (Fe) nanoparticles, which are generally oxidized at room temperature, still have good stability at 170 ° C. On the one hand, this is due to the protective effect of the carbon nanotubes. On the other hand, the Fe nanoparticles at the ends of the carbon nanotubes are rapidly oxidized into the spinel-type Fe3O4 / γ-Fe2O3 under room temperature and can effectively prevent Oxygen molecules diffuse into carbon nanotubes. Therefore, 170 ° C can be considered as the temperature limit at which oxygen molecules diffuse into the carbon nanotube cavity. Below 170 ℃, oxygen molecules can not penetrate the Fe3O4 / γ-Fe2O3 lattice in the lumen to form oxygen molecules. When the temperature is higher than 170 ℃, the oxygen molecule infiltration occurs, and the luminal Fe nanoparticles are gradually oxidized from the position close to the end of the tube to the inside. Due to the relatively good thermo-oxidative stability, the ferromagnetism of Fe-filled carbon nanotube-based composite fibers will be maintained over a much higher temperature range.