低功耗Mn-Zn铁氧体的制备及磁性能研究

发布时间：2018-10-30 10:09

【摘要】：本文利用工业纯的原始粉料通过氧化物陶瓷工艺制备了低功耗Mn-Zn铁氧体材料。系统研究了主配方含量、预烧温度、二次球磨时间、烧结温度、烧结气氛以及添加剂含量对Mn-Zn功率铁氧体的微观结构与磁性能的影响。 本文首先研究了主配方含量、预烧温度、二次球磨时间、烧结温度和气氛对Mn-Zn功率铁氧体的微观结构与磁性能的影响。结果表明，适合的主配方含量比为Fe2O3: ZnO: MnO=52.75:10.45:36.8(mol%)。随着Fe2O3和ZnO含量的增加，烧结样品μi-T曲线的II峰和功率损耗的最低点均移向低温。二次球磨时间对粉料的粒径平均值与峰值、比表面积和活性均有较大的影响，从而影响到烧结样品的固相反应过程，使样品呈现出不同的微观结构和磁性能。随着二次球磨时间的增长，由钢球的磨损产生的Fe2+对磁晶各向异性常数K1的补偿作用得到加强，使烧结样品μi-T曲线的II峰和功率损耗的最低点均移向低温。当预烧温度和二次球磨时间分别为920℃和2h时，烧结样品呈现出最佳的微观结构和磁性能。样品欠烧(1320℃)时，其细小的晶粒较多，晶粒的均匀性较差；样品过烧(1400℃)时，部分晶界发生明显的变形，局部区域出现熔融的夹杂物。欠烧或过烧的样品，其磁性能均相对较低；而经1340-1380℃烧结的样品，，其磁性能较为接近。此外，样品在最佳温度(1360℃)并配合二次还原气氛烧结时，可以增大磁性能的提升幅度。 其次，利用已经确定的主配方含量和球磨、预烧、烧结工艺，对比了微米和纳米TiO2的添加量对Mn-Zn功率铁氧体的微观结构和磁性能的影响。结果表明，适宜含量的微米和纳米TiO2添加，均能提升Mn-Zn功率铁氧体的磁性能。当纳米TiO2的添加量超过0.05wt%时，样品XRD谱中的峰位明显地移向高角度一侧。晶格的收缩使样品的内应力升高，从而使样品的磁性能发生恶化。此外，微量的纳米TiO2添加可以使样品内部的气孔和不纯物被隔离到晶界，从而使样品呈现出更加均匀的晶粒结构。100℃时，当微米TiO2的添加量逐渐增加到0.07wt%时，烧结样品的总功耗线性下降至315kW/m3。样品在90-120℃的温度范围内的总功耗低于330kW/m3。可见，微米TiO2的最佳添加量高于0.07wt%。此外，适宜含量的微米或纳米TiO2添加，均能提高Mn-Zn功率铁氧体的热稳定性。 最后，本文还研究了ZrO2含量对Mn-Zn功率铁氧体的微观结构和磁性能的影响。结果表明，适宜含量(0.02wt%)的ZrO2添加，使烧结样品呈现出最佳的微观结构和磁性能。然而，过量的ZrO2添加，将会导致样品的晶粒表面出现大量的裂口，使ZrO2颗粒通过裂口析出到晶粒表面并发生团聚。晶粒表面的气孔连同团聚的ZrO2颗粒对畴壁形成较大的钉扎效应，从而导致了样品磁性能的降低。
[Abstract]:In this paper, Mn-Zn ferrite materials with low power consumption were prepared by using industrial pure raw powder through oxide ceramic process. The effects of main formula content, pre-firing temperature, secondary ball milling time, sintering temperature, sintering atmosphere and additive content on the microstructure and magnetic properties of Mn-Zn power ferrite were systematically studied. In this paper, the effects of main formula content, pre-sintering temperature, secondary ball milling time, sintering temperature and atmosphere on the microstructure and magnetic properties of Mn-Zn power ferrite were studied. The results showed that the suitable content ratio of main formula was Fe2O3: ZnO: MnO=52.75:10.45:36.8 (mol%). With the increase of Fe2O3 and ZnO content, the II peak and the lowest point of power loss of the 渭 i-T curve of sintered samples are shifted to low temperature. The secondary milling time has a great influence on the average and peak particle size, specific surface area and activity of the powder, thus affecting the solid state reaction process of the sintered samples, and making the samples exhibit different microstructure and magnetic properties. With the increase of secondary milling time, the compensation effect of Fe2 produced by ball wear on the magnetocrystalline anisotropy constant K1 is strengthened, and the II peak and the lowest point of power loss of the 渭 i-T curve of sintered samples are moved to low temperature. When the pre-sintering temperature and the secondary milling time are 920 鈩

本文编号：2299703