燃烧法合成铁镍合金奈米粉末及包覆金的制程与特性

本报告以燃烧法所合成出来的铁镍合金,利用金属的硝酸盐类以低温燃烧法制备介金属的磁性奈米微粒,所使用的先驱物药品为硝酸铁(Fe(NO3)3·9H2O)及硝酸镍(Ni(NO3)2·6H2O),燃烧剂为卡巴胺(Carbohydrazide,CHZ),其制成铁镍颗粒大小约10～30 nm.在不同的参数条件下,比较包覆金(Au)之前的磁性与包覆后之磁性奈米微粒的型态,铁镍合金包覆金后仍然具有相当的磁性,其饱和磁化量随包覆金浓度增加而降低,而矫顽磁场与包覆金浓度成反比关系,金的最佳包覆浓度在C=2.02mg/ml与C=0.25mg/ml之间.     

低温燃烧合成制备NixZn1-xFe2O4(O.3≤x≤0.8) 铁氧体粉末与特性

本报告以低温燃烧法合成NixZn1-xFe2O4铁氧体粉末,整个燃烧合成在低温下进行.所得铁氧体粉末以X光粉末绕射法进行结构分析,并以穿透式电子显微镜进行粉末颗粒大小与形状之鉴定,再以振动样品测磁仪进行磁性质之量测.实验结果显示以低温燃烧合成法所制备之NixZn1-xFe2O4铁氧体粉末为立方晶结构,但在x=0.3～0.4之间时有γ-Fe2O3相出现,而在x=0.7～0.8之间有Ni结晶出现.磁性质方面,在x=0.4时饱和磁化量最高达81.2 emu/g,矫顽磁力达117.02 Oe.而在x=0.7时可得最大矫顽磁力142.5 Oe,此时饱和磁化量约为56 emu/g.以穿透式电子显微镜分析铁氧体颗粒大小约在10～30 nm之间,显示此方法可快速并且在低温下合成NixZn1-xFe2O4铁氧体粉末.     

Syntheses of Fe-Ni Magnetic Nanoparticles and Their Applications on Biologic Labeling

In this study, we compared FeNi alloy magnetic nanoparticles (MNPs) prepared by either combustion or chemical precipitation methods. We found that the FeNi MNPs generated by combustion method have a rather high saturation magnetization Ms of～180 emu/g and a coercivity field Hc of near zero. However, the alloy nanoparticles are easily aggregated and are not well dispersive such that size distribution of the nanoparticle clusters is wide and clusters are rather big (around 50～700 nm). To prepare a better quality and well dispersed Fe-Ni MNPs, we also developed a thermal reflux chemical precipitation method to synthesize FeNi3 alloy MNPs. The precursor chemicals of Fe(acac)3 and Ni(acac)2 in a molecular ratio 1,2-hexadecandiol and tri-n-octylphosphine oxide (TOPO) were used as reducer and surfactant, respectively. The chemically precipitated FeNi3 MNPs are well dispersed and have well-controlled particle sizes around 10～20 nm with a very narrow size distribution (±1.2 nm). The highly monodispersive FeNi3 MNPs present good uniformity in particle shape and crystallinity on particle surfaces. The MNPs exhibit well soft magnetism with saturation magnetization of ～61 emu/g and Hc～0. The biomedically compatible FeNi MNPs which were coated with biocompatible polyethyleneimine (PEI) polymer were also synthesized. We demonstrated that the PEI coated FeNi MNPs can enter the mammalian cells in vitro and can be used as a magnetic resonance imagine (MRI) contrast agent. The results demonstrated that FeNi MNPs potentially could be applied in the biomedical field. The functionalized magnetic beads with biocompatible polymer coated on MNPs are also completed for biomedical applications.