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铁纳米粒子样品系采用气体蒸发法制备,用透射电子显微镜观察其结晶形态和粒径大小,采用X射线衍射、电子衍射、X射线光电子能谱和俄歇电子能谱等多种分析手段详细分析了粒子表面氧化膜的组成、结构和厚度及其稳定性,提出了铁纳米粒子组成和结构模型。结果发现铁纳米粒子本身的晶体结构与普通α-Fe是一致的,为体心立方结构,粒子表面存在约3nm厚的双层氧化膜,外面一层为γ-Fe_2O_3,厚度约为1nm。里面一层为Fe_3O_4,厚度约为2nm,这两种氧化物均为尖晶石型立方结构。结果还表明,用气体蒸发法制备的铁纳米粒子在干燥空气中是相当稳定的,氧化膜虽薄但很致密,对粒子本身具有很好的保护作用。
The samples of iron nanoparticles were prepared by gas evaporation. The morphology and particle size of iron nanoparticles were observed by transmission electron microscopy. The analysis was carried out by X-ray diffraction, electron diffraction, X-ray photoelectron spectroscopy and Auger electron spectroscopy The composition, structure, thickness and stability of the oxide film on the surface of the particle were investigated. The composition and structure of the iron nanoparticle were proposed. The results show that the crystal structure of the iron nanoparticles is consistent with that of the common α-Fe, which is a body-centered cubic structure. The surface of the particles has a double-layer oxide film about 3 nm thick. The outer layer is γ-Fe 2 O 3 with a thickness of about 1 nm. Inside a layer of Fe_3O_4, a thickness of about 2nm, both oxides are spinel-type cubic structure. The results also show that the iron nanoparticles prepared by gas evaporation method are quite stable in dry air. Although the oxide film is thin but dense, it has a good protective effect on the particles themselves.