Catalysis Research Center, Hokkaido University, Nishi 10, Kita 21, Sapporo 001-0021, Japan.
Nanoscale. 2013 Feb 21;5(4):1489-93. doi: 10.1039/c2nr33467d.
Fe(x)Co(100-x) nanoalloys (NAs) with 20 ≤ x ≤ 80 were prepared by hydrogen reduction of Fe-Co oxide nano-composites, which were composed of mixed phases (or domains) of Fe(2)O(3) and CoO. In situ X-ray diffraction (XRD) measurements using synchrotron radiation clearly showed development of a solid-solution Fe-Co phase by hydrogen reduction from the oxide composites. High-resolution transmission electron microscopy (TEM), high-angle annular dark-field scanning TEM and powder XRD revealed that Fe-Co NAs form a single crystal structure and the two elements are mixed homogeneously. The saturation magnetization depends on the size and metal composition and shows the highest value (250 emu g(-1)) for the Fe(70)Co(30) NA in the size range of 30-55 nm, which is comparable to that of the Fe(70)Co(30) bulk alloy (245 emu g(-1)). This high magnetization is attributable to high crystallinity and homogeneous mixing of constituent atoms, which are attained by thermal treatment of oxide phases under a hydrogen atmosphere.
Fe(x)Co(100-x)纳米合金（NAs），其中 20 ≤ x ≤ 80，是通过 Fe-Co 氧化物纳米复合材料的氢气还原制备的，该复合材料由 Fe(2)O(3)和 CoO 的混合相（或畴）组成。使用同步辐射的原位 X 射线衍射（XRD）测量清楚地表明，通过从氧化物复合材料进行氢气还原，形成了固溶体 Fe-Co 相。高分辨率透射电子显微镜（TEM）、高角度环形暗场扫描 TEM 和粉末 XRD 表明，Fe-Co NAs 形成单晶结构，两种元素均匀混合。饱和磁化强度取决于尺寸和金属组成，并在 30-55nm 的尺寸范围内表现出最高值（250 emu g(-1))，对于 Fe(70)Co(30)NA，这与 Fe(70)Co(30)块状合金（245 emu g(-1))相当。这种高磁化强度归因于高结晶度和组成原子的均匀混合，这是通过在氢气气氛下对氧化物相进行热处理实现的。
