工艺因素及添加剂对猛锌铁氧体磁性能的影响

【作者】 谭维；

【导师】 章四琪；

【作者基本信息】 中南大学 ， 材料学， 2002， 硕士

【摘要】 本文实验采用传统的氧化物混合工艺制备锰锌铁氧体。以Mn₃O₄，Fe₂O₃和ZnO为原料，经过球磨，预烧，造粒，成型和烧结，最后得到环形锰锌铁氧体试样。实验中重点研究了氧化物添加剂，以及预烧程度，晶粒大小，气孔率，烧结气氛等因素对锰锌铁氧体性能的影响。实验涉及铁氧体显微结构的优化，如控制具有较窄的粒径分布的晶粒生长和缺陷，以利于制备性能优良的铁氧体。采用XRD和光学显微技术观察铁氧体微观组织结构，来评估上述各因素对铁氧体磁性能的影响。研究结果表明，随着球磨时间的增加，铁氧体晶粒随之细化；随着Bi₂O3，TiO₂，CaO和SiO₂添加量增加，铁氧体的初始磁导率降低；随着MoO₃添加量增加，铁氧体晶粒增大，同时气孔率也增大；在B₂O₃小于0.2wt．％范围内，随着B₂O₃添加量的增加，容易引起晶粒的不连续长大，但随着B₂O₃添加量的进一步增加（≥0.5wt％），铁氧体晶粒粒径分布窄；提高铁氧体平均晶粒尺寸将有助于提高锰锌铁氧体的初始磁导率。更多还原

【Abstract】 In this paper, Mn-Zn ferrites have been prepared by the mixed-oxide route. The prescribed quantities of Mn₃O₄ Fe₂O₃ and ZnO as the starting materials, were mixed in a ball mill. After being calcinated, the obtained ferrite powder was granulated and pressed into toroidal shapes, mixing with PVA. They, then, were sintered under nitrogen atmosphere. In this study, the effect of a small amount addition of many different oxides on the various properties of Mn-Zn soft ferrite was investigated. At the same time, we also examined the effect of calcination ratio, pressure, grain size, porosity, sintering atmosphere on the initial permeability and other material characteristics. The experiments are related to the optimization of microstructure, esp. the control of grain growth with a narrow distribution of the grain size and the control of defects. Therefore the use of optimized technology was necessary in order to obtain better homogeneity of raw material and good densification of green bodies and optimum sintering. To assess the effect of those factors, XRD and typical optical microscopy were used to investigate the microstructure. The results show that the average grain size of the ferries reduces due to the increase of the milling time; that the initial permeability of the manganese-zinc ferrites decreases remarkably with the increase of some oxide additions, i.e., 61263, TiOz, CaO and SiC^; that the average grain size and the porosity in ferrites increase drastically, as the higher content of MoOs addition; that a structure showing discontinuous grain growth is observed in ferrites with the addition of small amounts of 6263 up to 0.2 wt.%. Further increase in the doping level （^0.5 wt.%） , a relatively uniform microstructure with large grain size is obtained; that increasing the average grain size contributes to the initial permeability of the ferries. Those will serves as bases on the development of even better high-permeability ferrite materials.更多还原