高磁导率MnZn铁氧体的配方和烧结工艺

高磁导率MnZn铁氧体作为现代电子行业和信息产业中的一项基础性材料,在现代信息技术的不断发展中,高磁导率MnZn铁氧体正在向着高频率、低损耗的方向发展,促进着人们对高磁导率MnZn铁氧体配方和烧结工艺研究力度的不断加深。在提高MnZn铁氧体磁导率上,其主要是通过优化配方和改善烧结工艺来实现的,基于此,文章以综述的方法,对高磁导率MnZn铁氧体的配方和烧结工艺进行了阐述。     

面向5G应用第3代半导体功率器件的高频低功耗MnZn铁氧体研究进展

随着5G通信技术的发展和第3代宽禁带半导体广泛的商用，功率电子器件朝着高频化、小型化和高能效化的方向加速发展。MnZn铁氧体作为功率电子器件的核心材料，成为学术界和产业界在高频软磁材料方面研究的焦点。本综述主要介绍近年来Mn Zn铁氧体在高频化方向上最新的研究进展，包括通过主成分设计、添加剂调控和低温烧结工艺等手段，实现高频、宽温和低损耗等特性，以及高频下MnZn铁氧体损耗的应力敏感性。随着高频损耗发生机制研究的深入，今后5到10年内将会开发出更多的在0.5 MHz以上的高频和更高的磁通密度下表现出更低损耗的MnZn铁氧体新材料，并迅速应用于通信电源等领域。     

贫铁锰锌铁氧体材料电磁特性

用传统陶瓷工艺制备MnZn和NiZn铁氧体材料.在富铁MnZn铁氧体材料Curie温度经验公式的基础上,提出了贫铁MnZn铁氧体材料Curie温度的经验计算公式.比较研究了贫铁MnZn铁氧体、富铁MnZn铁氧体和NiZn铁氧体材料的起始磁导率和电阻率的频率特性.在低频区域,贫铁MnZn铁氧体的高起始磁导率与富铁MnZn铁氧体相当;在高频区域,贫铁MnZn铁氧体的高起始磁导率与NiZn铁氧体相当;贫铁MnZn铁氧体的电阻率高达103 Ω·m.贫铁MnZn铁氧体几乎兼具了富铁MnZn铁氧体的低频特性和NiZn铁氧体的高频特性,且Curie温度也不低,是一种很有应用潜力的软磁铁氧体材料.     

宽温低损耗MnZn功率铁氧体研究进展

MnZn功率铁氧体广泛应用于高频功率电力电子器件。功率损耗是其最重要的电磁性能指标。宽温低损耗的实现不但可以提高磁性元件在满载工况下的电能转换效率,降低能量损失,而且可以降低设备的待机损耗,提高设备工作时的温度稳定性。本文介绍了实现MnZn功率铁氧体宽温低损耗的途径,总结了国内外宽温低损耗MnZn功率铁氧体的生产和研究开发方面的进展,并对其未来的发展进行了展望。     

ZrO2和SnO2复合掺杂对贫铁配方的MnZn铁氧体磁性能和电性能的影响

通过ZrO2与SnO2复合掺杂制备了低损耗的MnZn铁氧体材料.研究了在贫铁配方的基础上添加SnO2-ZrO2对MnZn铁氧体微观结构、电性能以及磁性能的影响.结果表明,适量的SnO2-ZrO2复合掺杂有利于促进晶粒均匀致密,明显提高了材料的电阻率,降低比损耗因子,在ξ(SnO2:ZrO2)为3:1时材料的电阻率达到最大值29.5 Ωm,比损耗因子达到最小值4.8×10-6.复合掺杂还能提高材料的居里温度、饱和磁感应强度和起始磁导率,当ξ(SnO2:ZrO2)为3:1时磁性能都达到最佳.     

添加钛和锡对锰锌铁氧体微结构和高频性能的影响

用氧化物陶瓷工艺制备了MnZn功率铁氧体.结合材料微观结构分析,研究了TiO2,SnO2添加剂对MnZn功率铁氧体起始磁导率μi,电阻率ρ及单位体积高频损耗Pcv的影响.结果表明:为得到优良的高频性能,TiO2和SnO2适宜添加的质量分数(下同)分别是0.2%和0.1%,而复合添加时最佳量分别为0 4%和0.1%.     

MnZn铁氧体承烧板性能的比较

部分稳定氧化锆材料(PSZ)以其优良的高温化学稳定性和抗热震性而成为MnZn铁氧体承烧板的首选材料。PSZ材料在1100℃以上反复使用会发生反稳定化现象。本文对比了钙稳定氧化锆(Ca-PSZ)和钇稳定氧化锆(Y-PSZ)反稳定化现象,及反稳定化现象对材料物理性能的影响。结果表明:Y-PSZ晶相更为稳定,性能也更为稳定,更适合用于MnZn铁氧体的承烧。     

MnZn.功能陶瓷常用添加剂研究现状

介绍了MnZn功率铁氧体的晶体结构及其损耗机理,综述了MnZn功率铁氧体常用添加剂CaO、SiO_2、Nb_2O_5、Ta_2O_5、CoO等对其结构和磁性能影响的发展现状。研究表明,掺入有效杂质已经成为获得高性能MnZn功率铁氧体陶瓷的关键,也是各研究者的技术秘密。添加剂能明显改善MnZn功率铁氧体的微观结构和温度特性,提高其磁性能和晶界电阻率,降低功率损耗P_（cv）。     

MnZn.功能陶瓷常用添加剂研究现状

介绍了MnZn功率铁氧体的晶体结构及其损耗机理,综述了MnZn功率铁氧体常用添加剂CaO、SiO₂、Nb₂O₅、Ta₂O₅、CoO等对其结构和磁性能影响的发展现状。研究表明,掺入有效杂质已经成为获得高性能MnZn功率铁氧体陶瓷的关键,也是各研究者的技术秘密。添加剂能明显改善MnZn功率铁氧体的微观结构和温度特性,提高其磁性能和晶界电阻率,降低功率损耗P_cv。     

MnZn铁氧体/SrTiO3/PTFE复合材料的制备与表征

采用SrTiO3溶胶对MnZn铁氧体进行表面改性，得到MnZn铁氧体／SrTiO3复合粉体，以PTFE为基体，制备了的MnZn铁氧体／SrTiO3／PTFE复合材料。采用HP4292B和HP4294对复合材料电磁性能进行了表征。结果表明：复合材料在低频阶段具有较高磁导率和介电常数以及较低磁损耗和介电损耗，复合材料的介电频率响应符合德拜弛豫理论。     

铁氧体磁性材料烧结技术

烧结技术对铁氧体的性能具有决定意义,一直是科学界研究的热点问题。本文综述了近年来铁氧体磁性材料的烧结技术,主要包括固相烧结、液相烧结、等离子体烧结和微波烧结,分析总结了不同烧结技术的发展现状、优缺点及改进措施,并对铁氧体磁性材料今后的发展趋势和烧结技术作了展望。     

Li2MoO4‐based composite ceramics fabricated from temperature‐ and atmosphere‐sensitive MnZn ferrite at room temperature

The first magnetic ceramic composites manufactured, using the room‐temperature densification method are reported. The samples were prepared at room temperature using Li₂MoO₄ as a matrix and MnZn ferrite with loading levels of 10‐30 vol‐% followed by postprocessing at 120°C. The method utilizes the water solubility of the dielectric Li₂MoO₄ and compression pressure instead of high temperatures typical of conventional solid‐state sintering. Hence, composite manufacturing using temperature‐ and atmosphere‐sensitive materials is possible without special conditions. This was demonstrated with MnZn ferrite, which is prone to oxidation when heat treated in air. Samples manufactured with room‐temperature densification showed no signs of reactivity during processing, whereas reference samples sintered at 685°C suffered from oxidation and formation of an additional reaction phase. The densities achieved with different loading levels of MnZn ferrite with both methods were very similar. Measurements up to 1 GHz showed relatively high values of relative permittivity (21.7 at 1 GHz) and permeability (2.6 at 1 GHz) with 30 vol‐% loading of MnZn ferrite in the samples manufactured by room‐temperature densification. In addition, pre‐granulation is proposed to improve the processability of the composite powders in room‐temperature densification.     

MnZn铁氧体磁心烧结裂纹成因浅探

MnZn铁氧体磁心生产过程较复杂,裂纹是导致质量问题的重要因素。笔者针对导致烧结裂纹的各种原因进行了分析,并根据生产实践经验提出了一些解决办法。     

A review on MnZn ferrites: Synthesis,characterization and applications

Researchers are taking great interest in the synthesis and characterization of MnZn ferrites due to their wide range of applications in many areas. MnZn ferrites are a class of soft magnetic materials that have very good electrical, magnetic and optical properties. The properties of MnZn ferrites include high value of resistivity, permeability, permittivity, saturation magnetization, low power losses and coercivity. The above mentioned advantageous features of MnZn ferrites make them suitable for the use in various applications. In biomedical field these ferrites are used for cancer treatment and MRI. MnZn ferrites are also used in electronic applications for making transformers, transducers and inductors. These ferrites are also used in magnetic fluids, sensors and biosensors. MnZn ferrite is highly useful material for several electrical and electronic applications. It finds applications in almost every household appliances like mobile charger, LED bulb, TV, refrigerator, juicer mixer, washing machine, iron, microwave oven, mobile, laptop, desktop, printer and so on. Therefore, the present review focuses on different techniques for synthesis of MnZn ferrites in literature, their characterization tools, effect of doping on the properties of MnZn ferrite and finally we will discuss about their applications.     

MnZn铁氧体磁心烧结裂纹成因浅探

MnZn铁氧体磁心生产过程较复杂,裂纹是导致质量问题的重要因素。笔者针对导致烧结裂纹的各种原因进行了分析,并根据生产实践经验提出了一些解决办法。     

Effect of a YIG nanoparticle additive on the magnetic properties of MnZn ferrites for MHz frequency applications

In this study, MnZn ferrites with added YIG nanoparticles were developed for MHz frequency applications. The effect of the magnetic YIG additive on the power loss, initial permeability, and cutoff frequency of MnZn ferrites was investigated. A small quantity of added YIG effectively reduces the power loss and concurrently increases the initial permeability. Compared to the results for the MnZn ferrite with no added YIG, the optimal MnZn ferrite with 600 ppm added YIG exhibits a reduction in the power loss at 25°C of 56.4% and 36.6% at 1 MHz/50 mT and 3 MHz/10 mT, respectively, and a 13.9% increase in the initial permeability. This sample also exhibits a good stability of the power loss against temperature. The power loss remains below 205 kW/m³ over temperatures ranging from 25 to 140°C. The effect mechanism of YIG addition on the magnetic properties of MnZn ferrites was studied. An analysis based on the equivalent circuit model showed that the reduction in the eddy current loss and power loss mainly results from the increase in the grain boundary resistance caused by the addition of highly resistive YIG.     

Sintering of Nanosized MnZn Ferrite Powders

The sintering and microstructural evolution of nanosized MnZn ferrite powders prepared by a hydrothermal method were investigated. The microstructure of sintered ferrite compacts depends strongly on the strength of the agglomerates formed during the compacting of nanosized ferrite powders. It was found that at 700°C the theoretical density of sintered compacts can almost be reached, while above 900°C an increase of porosity was identified. The formation of extra porosity at higher sintering temperatures is caused mainly by the oxygen release which accompanies the dissolution of relatively large grains of residual alpha-Fe₂O₃ in the spinel lattice.     

The effects of Barium Strontium Titanate (BST) on the soft magnetic properties and loss performance of MnZn ferrites

With the increasing power density of the switched mode power supply (SMPS) developed nowadays, higher efficiency is required from the magnetic core, where the MnZn ferrites are often adopted. However, the relatively high operating temperature of the SMPS often results in reduced resistivity of the MnZn, which increases the eddy current loss. To enhance the resistivity of MnZn ferrite at high temperature range (>100 °C), donor-doped barium strontium titanate (BST) with a positive temperature coefficient of resistivity (PTCR) is prepared and dopped in the MnZn ferrite. The influence of BST addition from 0.000 wt% to 0.020 wt% on the MnZn ferrite is investigated over a wide temperature range from 25 °C to 140 °C. The XRD result suggests ionic exchange between the spinel phase and perovskite phase. The SEM result shows a refined and more uniform microstructure of MnZn ferrite brought about by the BST addition. At the maximum of 0.020 wt%, the BST addition shows almost no influence on density and the saturation magnetic induction. However, the initial permeability is slightly reduced by the BST addition, due to the microstructural change. Moreover, the BST concentrating at the grain boundaries improves the DC-resistivity across the temperature range from 25 °C to 140 °C. Due to the addition of BST, the reduction in eddy current loss at 300kHz/100 mT is around 35% at 25 °C, and ∼20% reduction at 140 °C.     

微波石榴石型铁氧体低温烧结的研究进展

石榴石型铁氧体材料是微波技术中一种重要的功能材料.综述了YIG(Y3Fe5O12)多晶铁氧体材料在低温烧结方面的研究现状.总结了实现微波YIG低温烧结的途径.阐述了目前存在的问题,并指出了未来的研究方向.