本篇論文主要是以微乳化系統中的逆微胞法,來製備FePt@Au及CoPt@Au磁性核殼型奈米粒子。首先是以合金的方式成功的製作出FePt及CoPt合金粒子,再以逆微胞法製作出核殼型FePt@Au及CoPt@Au奈米粒子。實驗主要是利用硫酸亞化鐵 (FeSO4 FeSO4-7H2O)、二氯化鈷 (CoCl2-6H2O)、四氯化白金(PtCl4)為前驅鹽,硼氫化鈉(NaBH4)為還原劑,加入四氯金酸(HAuCl4.4H2O)為反應物,並利用CTAB為界面活性劑,正-丁醇(n- Butanol)為輔助界面活性劑,正-辛烷(n-Octane)為油相,水為分散相,整個實驗在常壓下進行且控制溫度在25℃,與一般需在真空中或高純氬氣下製作有明顯的不同。藉由穿透式電子顯微鏡(TEM)、X光繞射儀(XRD)、紫外光-可見光光譜儀(UV-Vis)、以及超導量子干涉儀(SQUID)分析樣品特性。結果證明樣品確為FePt@Au及CoPt@Au核殼型奈米粒子,其平均粒徑約為6 nm ~ 7 nm。且經由SQUID磁性量測的結果,發現FePt@Au及CoPt@Au均具有超順磁的特性,其阻隔溫度Tb(blocking temperature)分別為65K及75K。同時,其在絕對溫度為5K時的矯頑磁化力,分別為350 Oe及20 Oe。
In this thesis, magnetic FePt@Au and CoPt@Au nanoparticles are prepared by reverse micelle method under ambient pressure, and investigated by X-ray diffraction, transmission electron microscopy (TEM), ultraviolet-visible absorption spectra, and Superconducting Quantum Interference Device (SQUID) measurements. FePt and CoPt nanoparticles are synthesized via chemical assembly, and achieved by reducing 0.1 M aqueous metal salts confined in the polar portions of inverse micelles of cetyltrimethylammonium bromide (CTAB) with borohydride. Gold-coated nanocomposites are prevented FePt and CoPt oxidation and allowed the samples to be manipulated without additional precautions to prevent oxidation. The results of X-ray diffraction show that the patterns of FePt and CoPt are hidden under the pattern of gold. TEM images reveal that the core-shell structure is obviously observed and the average sizes of FePt@Au and CoPt@Au nanoparticles are about 6~7nm. The absorption bands of FePt@Au and CoPt@Au nanoparticles shift to a longer wavelength and broadens relative to that of the pure gold. These results indicate that the preparations of the FePt@Au and CoPt@Au nanoparticles are successful synthesized by reverse micelle method under ambient pressure. The results of magnetization for FePt@Au and CoPt@Au nanoparticles reveal that they are super-paramagnetic, and the blocking temperatures are 65K and 75K for FePt@Au and CoPt@Au nanoparticles, respectively. In addition, the coercive fields are 350 Oe and 20 Oe for FePt@Au and CoPt@Au nanoparticles, respectively.