本研究利用不同程序的化學共沉澱法，合成不同型態的四氧化三鐵奈米微粒，其中實驗重點之一在於使用單一原料: 硫酸亞鐵為前驅鹽, 先使用過氧化氫將之氧化為三價，再以恰當比例混合，並用氫氧化鈉共沉澱合成出四氧化三鐵奈米粒子，當中以TX-100當作保護劑使之均勻分散。實驗重點在於藉由製程上的變化得到不同形態的四氧化鐵粒子，若將前驅鹽溶液和氫氧化鈉溶液分別使用蠕動幫浦同時滴入分散劑TX-100溶液中，所得到四氧化三鐵球形粉末大小均勻。此外吾人亦曾使用兩階段方式添加NaOH，並藉由如IPA, EG, 甘油分子的添加可以得到高轉化率的針狀粒子。成品粉末則使用X光繞射光譜儀(XRD)、超導量子干涉磁量儀(SQUID)、高解像能電子顯微鏡(HRTEM)和掃描式電子顯微鏡(SEM) 、BET來分析粒徑大小、粒徑均勻度、磁性、比表面積與晶體結構等特性，期能探討合成條件與成品特性間的關係，未來則繼續製得電極以作為電池應用，而尋求最佳表現之粉末特性。
In this research, we tried several different precipitation processes to synthesize Fe3O4 nanoparticles with different morphologies. We used only one precursor, i.e. FeSO4, which was oxidized to ferric sulfate by hydrogen peroxide. The two solutions were then mixed in appropriate ratio to obtain Fe3O4 using NaOH as the precipitant. TX-100 was used as a protective agent to keep the particles uniform. When both iron precursor solution and NaOH solution was pumped separately into TX-100 solution, spherical Fe3O4, uniform in size, was obtained. On the other hand, a two-step procedure, with the addition of molecules such as IPA, EG (ethylene glycol) or glycerol, we would get Fe3O4 particles in needle shape and also having complete (100%) conversion. The powders were then characterized by techniques such as XRD, SQUID, HRTEM, SEM, BET to obtain information on many characteristics of powders, such as size and uniformity, particle morphology, magnetic property, specific surface area, crystallinity, etc.. It is our hope to find correlation between these characteristics and processing conditions. These powders will be further processed as electrode materials and tested in a battery to find optimal performance.
For silver coated magnetic particles, we used AgNO3 and either IPA or EG as reducing agent and spherical Fe3O4 nanoparticles as core. The relative ratio between AgNO3 and Fe3O4 was varied with the objective to get uniform coating. The powders thus obtained was also subjected to several characterization techniques to get information on coating uniformity, crystalline nature, and magnetic property.