爆炸法合成纳米α-Fe_2O_3

SYNTHESIS OF α-Fe_2O_3 NANOPOWDER BY EXPLOSIVE METHOD

以微米级还原铁粉为反应原料,通过爆炸法合成了纳米级α-Fe2O3粉体。研究了炸药种类、炸药与铁粉的配比以及冷却介质对合成粉体特性的影响,并用激光粒度分析仪、X射线衍射、透射电镜等手段对产物进行了表征,同时对爆炸反应场的作用机理进行了初步探讨。结果表明:选择负氧平衡指数在-0.59到-0.61之间的混合炸药并控制铁粉和炸药的质量比在70:30到80:20之间,可以制备出粒度为40-50nm、纯度在99%以上的α-Fe2O3粉体。爆炸场的作用机理一方面在于爆炸产生的气体以及高温高压场为纳米粒子的合成和相转变提供了基本的物质和能源;另一方面负氧平衡炸药在爆炸时产生的类气态自由碳在纳米粒子表面沉积,发挥了空间位阻效应,阻止了纳米粒子的生长和团聚。

α-Fe2O3 nanopowder was synthesized by explosive method with reductive iron micron powder as raw material in a steel chamber. The effects of different explosives, the mass ratio of iron powder versus explosives and cooling mediums on the characteristics of the products were investigated. Laser granularity analysis, X-ray diffraction, and transmission electron microscopy were used to analyze the products. The action mechanism of the explosion reaction field was also discussed elementarily. The results indicate that α- Fe2O3 nanopowder with a size of 40 50 nm and 99% purity was obtained when using the explosives with an oxygen balance index from-0.59 to -0.61 were used and when the mass ratio of iron powder versus explosive was kept between 70 ： 30 to 80 ： 20. The action mechanism of the explosion reaction field can be explained by the fact that the oxygen produced during detonation as well as the high temperature and high pressure of the field provide the basic material and energy for synthesis and crystallization of α - Fe2O3 nanopowder. The dissociative carbon black produced by negative oxygen balance explosives during detonation is deposited on the surface of the nanoparticles, which exerts a steric stabilization function and results in preventing the growth and conglomeration of nanoparticles effectively.