花状自组装FePt纳米颗粒的制备

选用硼氢化钠(NaBH4)作为还原剂,聚乙二醇(PEG2000)作为表面活性剂,利用简单的湿化学还原工艺,在室温下制备花状自组装的FePt纳米颗粒。XRD和TEM表征显示:所制备的FePt纳米颗粒是化学无序的面心立方(fcc)结构。颗粒形貌主要由平均粒径分别为19.2和4.9nm的梭形和球形颗粒组成。这些梭形的"花瓣"和球形的"花蕊"自组装形成大小不等的花状结构。推测认为,纳米颗粒的花状自组装主要是表面活性剂集合的结果。VSM显示所制备FePt纳米颗粒的磁性能室温下为超顺磁性,饱和磁化强度Ms约为10.9(A·m2)/kg,相同条件下PVP作为表面活性剂时Ms约为0.6(A·m2)/kg,两者比较,选用PEG作为表面活性剂,Ms大约增大18倍。

Preparation of FePt Nanoparticles with Flower-Like Assembly

FePt nanoparticles with flower-like assembly were synthesized at room temperature by a simple wet chemical reduction process using NaBH4 as the reducing reagent and PEG as the surfactant.XRD and TEM characterizations show that the as-synthesized FePt particles are possessed of chemically disordered face-centered cubic(fcc) structure.The shapes present the fusiform and the spherical with the mean sizes of 19.2 and 4.9 nm,respectively.These fusiform "petals" and spherical "stamens" are found to be assembled into flower-like structures.We suggest that the formation of flower-like assemble of FePt nanoparticles is result from the surfactant assemblage.VSM indicates that the as-synthesized samples show paramagnetic property at room temperature with the saturation magnetization Ms 10.9(A?m2)/kg.when PVP is used as surfactant,Ms is about 0.6(A?m2)/kg.comparing the nanoparticles synthesized and the same condition,Ms increases by 18 times when PEG is used as surfactant.