纳米锰锌铁氧体粉体的沸腾回流法制备及性能研究

发布时间：2018-04-23 20:35

本文选题：锰锌铁氧体 + 沸腾回流法　；参考：《华南理工大学》2010年硕士论文

【摘要】： 纳米磁性材料是当今磁性材料研究的热点,软磁材料中品种最多、用量最大、应用最广泛的是软磁铁氧体材料。纳米锰锌铁氧体材料作为一种重要的软磁材料具有广阔的应用前景。本文对纳米软磁锰锌铁氧体粉体的制备方法及性能进行了研究。本文采用沸腾回流法,以δ-FeOOH为前驱体,直接合成了尖晶石结构的MnZn铁氧体纳米粉体。研究了共沉淀pH值、反应时间等工艺因素对产物的影响,得出了合适的共沉淀沸腾回流法制备工艺；采用XRD、TEM、VSM等测试手段对产品进行了表征,对回流相转化反应动力学、热力学、反应机理、磁性能等进行了分析研究。研究表明,通过调节pH值和回流时间可以得到从小于10nm到大于20nm不同粒径的锰锌铁氧体粉体,获得完全产物的最佳回流时间为6h。pH值对反应剧烈程度及磁性能有很大影响,共沉淀pH值为13.0左右时获得的制备态纳米粉末尺寸约为20nm,饱和磁化强度达46A.m2/kg。为了抑制纳米粉体的团聚,将物理分散与化学分散结合起来,利用物理手段解团聚,然后加入分散剂实现颗粒的稳定化,可以达到较好的分散效果,得到了具有良好分散性的锰锌铁氧体纳米粉体。本文还研究了稀土元素(La、Nd、Gd)取代对尖晶石铁氧体结构和磁性能的影响。当稀土离子取代尖晶石铁氧体晶格中的Fe3+时,稀土离子可能会进入尖晶石晶格,也可能形成化合物进入晶界。经研究发现由于稀土离子(La3+、Nd3+、Gd3+)的有效磁距与离子半径的差异,稀土离子的掺入会减少尖晶石铁氧体的晶格常数和晶粒尺寸,而其矫顽力Hc得以提高,饱和磁化强度变化与稀土离子的添加量有关。
[Abstract]:Nanomagnetic materials are the research hotspot of magnetic materials at present. The soft magnetic materials are the most widely used in the field of soft magnetic materials, and the most widely used materials are the soft magnetic ferrite materials. Nanocrystalline manganese zinc ferrite as an important soft magnetic material has a broad application prospect. In this paper, the preparation method and properties of nanometer soft magnetic manganese zinc ferrite powder were studied. In this paper, MnZn ferrite nanocrystalline powders with spinel structure were synthesized by boiling reflux method with 未 -FeOOH as precursor. The effects of coprecipitation pH value, reaction time and other technological factors on the product were studied, and a suitable preparation process by co-precipitation boiling reflux method was obtained, and the product was characterized by XRDX TEM VSM, and the reaction kinetics and thermodynamics of the reflux phase conversion reaction were also studied. The reaction mechanism and magnetic properties were studied. The results show that manganese zinc ferrite powders with different particle sizes from 10nm to 20nm can be obtained by adjusting pH value and reflux time. The optimum reflux time of complete product is 6h.pH value, which has great influence on the intensity of reaction and magnetic properties. When the pH value of coprecipitation is about 13.0, the size of the prepared nano-powder is about 20nm, and the saturation magnetization is 46A.m-2 / kg. In order to restrain the agglomeration of nanometer powder, the physical dispersion and chemical dispersion are combined, the agglomeration is solved by physical means, and then the dispersant is added to realize the stabilization of the particles, which can achieve a better dispersion effect. Nano-sized manganese zinc ferrite powders with good dispersion were obtained. The effect of the substitution of rare earth element La NdGd) on the structure and magnetic properties of spinel ferrite has also been studied. When rare earth ions replace Fe3 in spinel ferrite lattice, rare earth ions may enter spinel lattice or form compounds to enter grain boundary. It is found that the addition of rare earth ions can decrease the lattice constant and grain size of spinel ferrite due to the difference of effective magnetic distance and ionic radius between La _ 3 and ND _ 3 Gd _ 3), and increase its coercivity HC. The change of saturation magnetization is related to the addition of rare earth ions.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TB383.1

【参考文献】