成型压强对FeSiB磁粉芯磁性能的影响

磁粉芯作为软磁材料的新兴发展成果相较于传统软磁材料在电力电子方面有着巨大的应用潜力。本文以气雾化FeSiB磁粉末为原料,经过预处理、包覆、成型压制和退火处理等过程制备了FeSiB磁粉芯,并研究了不同成型压强对磁粉芯磁性能的影响。结果表明,经钝化处理后的FeSiB粉末相比于未钝化粉末具有更稳定、致密的表面包覆层,提高了磁粉芯的电阻率、降低了磁损耗。对比不同成型压强下磁粉芯的磁性能,得出随着压强的增加,磁粉芯的磁导率先增加后减小,且在较宽频率范围内有着稳定的频率特性,当成型压强为1 400 MPa,f为100 kHz,B_m为50 mT时,磁粉芯表现出良好的软磁性能,其中磁导率为17.66,磁损耗为103.04 W/kg,Q值为64.34。     

案例二：量身定制测量方案 助推企业产品开发

<正>1案例概况1.1实施背景铁硅铝软磁合金，又称仙台合金，具有综合软磁性能好、成本低等优点。铁硅铝粉末制备的磁粉芯因其良好的偏置特性和温度稳定性，能够在较宽的温度范围内工作，并且工作时噪音低，在开关电源磁芯、线路滤波器、脉冲回归变压器、储能滤波电感器、功率因素校正器等器件中得到了广泛应用。     

铁基纳米晶软磁粉芯研制进展概述

1988年Yoshizawa等报道了著名的Fe73.5Cu1Nb3Si13.5B9合金,它具有饱和磁感高,磁导率高,稳定性好及热处理后带材变脆容易加工成合金粉等特点.由于其性能优异,价格低廉,其粉末及粉末制品用作磁性器件的研究开发工作得到迅速发展.目前,铁基纳米晶软磁粉芯正沿着高频、多功能方向发展,其应用领域将遍及软磁材料应用的各方面.概述了磁粉芯的发展及铁基纳米晶软磁粉芯制备与性能研究.     

磁粉芯的研究进展

磁粉芯具有良好的软磁性能和频率特性,广泛应用于电感元件和变压器.分类介绍了纯铁粉芯、坡莫合金粉芯、铁硅铅粉芯、非晶和纳米晶粉芯的成分组成及其磁性能,重点阐述了粉末制备、绝缘包覆、压制成型和热处理等工艺参数对磁粉芯软磁性能的影响,最后指出新制备工艺的开发和相关理论模型的构建将成为未来磁粉芯研究的热点.     

粉末挤出成型法制备FeSiAl/FeCuNbSiB磁粉芯

采用粉末挤出成型法制备了FeSiAl/Fe-CuNbSiB纳米晶磁粉芯,并讨论了FeSiAl粉复合量、粉胶质量比对磁粉芯磁性能的影响。结果表明粘结剂配方为硬脂酸1%、聚丙烯20%、石蜡79%,挤出成型粉胶质量比10∶1的FeSiAl/FeCuNbSiB纳米晶磁粉芯,磁粉芯密度达到4.69g/cm3。200目FeSiAl粉与300目FeCuNbSiB纳米晶粉复合,当磁粉芯磁粉质量配比为"200目FeSiAl粉30%+300目FeCuNbSiB纳米晶粉70%"、粉胶质量比为10∶1、44℃×0.5h石油醚脱脂、热处理温度160℃×1h时,磁粉芯取得最佳的软磁性能,磁粉芯中心频率f为600kHz,有效磁导率μe达到16.48,品质因数Q值为57.5;频率及温度的变化对磁粉芯的有效磁导率的影响小。     

铁粉粒径和硅树脂含量对铁基复合磁粉芯软磁性能的影响

将不同粒径铁粉颗粒和适量高温硅树脂进行充分混合,在铁粉颗粒表面上均匀包覆一层硅树脂,采用粉末压实成型工艺将铁粉-硅树脂复合粉末制备成致密的铁基复合磁粉芯。系统研究铁粉粒径和硅树脂包覆量对磁粉芯密度及软磁性能的影响,探索最佳铁粉粒径大小和硅树脂包覆量。研究表明,在相同粒径下,磁粉芯的密度、涡流损耗和磁感应强度均随硅树脂包覆量增加而降低。在相同硅树脂包覆量下,磁粉芯的密度和涡流损耗随粒径增大而增加,磁滞损耗却随着粒径增大而降低。在平均粒径为120μm的铁粉表面上均匀包覆0.5%硅树脂可制备出高密度、低损耗和较高磁感应强度的复合磁粉芯,在大功率条件下,较好软磁性能参数为Ps(B=1T,f=400Hz)=69 W/kg,B4k(H=4000A/m)=0.96T。     

羰基铁粉/FeSiBCCr复合非晶磁粉芯的性能

随着5G时代的到来,数量庞大的基站建设对低损耗、高频特性、大功率软磁复合磁粉芯的需求不断增长,同时,宽禁带半导体技术的迅速发展对电子器件的小型化、高频化、高功率密度提出了更高的要求.然而,几乎没有软磁材料能够满足第三代宽禁带半导体的外源环境要求,这进一步制约了下一代电子器件的发展.为了满足发展需求,本工作通过将具有高饱和磁化强度(Ms)的羰基铁粉(Carbonyl iron powder,CIP)与水雾化FeSiBCCr微细非晶粉末复合,成功制备了综合软磁性能优异的FeSiBCCr复合非晶磁粉芯.研究结果表明,与没有复合CIP的FeSiBCCr非晶磁粉芯相比,当CIP含量为20％(质量分数,下同)时,FeSiBCCr复合非晶磁粉芯的Ms提高到160 emu/g左右,整体提高约6.7％;在100 Oe外加直流场下,FeSiBCCr复合非晶磁粉芯的直流偏置性能达到72％,提高了10.8％;在0.05 T@100 kHz条件下,FeSiBCCr复合非晶磁粉芯的损耗降低至296 mW/cm3,整体降低11.6％;FeSiBCCr复合非晶磁粉芯的有效磁导率和品质因数分别提高到47.0和174,提高了14.6％和9.4％.通过复合不同含量的CIP制备的新型FeSiBCCr复合非晶磁粉芯具有高的饱和磁化强度、低的损耗和良好的直流偏置特性,有望满足高频大电流器件的需要,在高频电磁系统中具有良好的应用前景.     

金属磁粉心的研究现状及发展趋势

金属磁粉心材料由金属软磁粉末、有机或无机绝缘添加剂和粘结剂组成,其是以金属软磁粉末为原料,经过绝缘包覆、压制成型和热处理等工艺制成的软磁复合材料。本文系统阐述了金属磁粉心材料的材料分类、制备工艺、磁性能及其应用,同时对其未来的发展趋势做了预测,为今后金属磁粉心的研究与发展提供了参考。     

粉末挤出成型法制备FeCuNbSiB纳米晶磁粉芯

采用粉末挤出成型法制备了FeCuNbSiB纳米晶磁粉芯,并讨论了纳米晶粉体粒度对磁粉芯磁性能的影响。结果表明,粘结剂配方为硬脂酸1%、聚丙烯40%、石蜡59%采用粉末挤出成型法可以制备粉体与粘结剂比例为5∶1的FeCuNbSiB纳米晶磁粉芯;粉级搭配可提高磁粉芯密度,300、200与100目质量比为6∶3∶2的磁粉芯密度相对于300目FeCuNbSiB纳米晶磁粉芯提高了5%,达到了3.76g/cm2;200目FeCuNbSiB纳米晶粉为33%,180℃、1h热处理,磁粉芯有效磁导率μe为10.44、中心频率为600kHz、中心频率品质因数Q值为44。     

通过改进的制备工艺提高FINEMET纳米晶磁粉芯的磁性能及其机理

通过对比实验研究了改进的制备工艺下FINEMET纳米晶磁粉芯的磁性能,并探讨了其相应的物理机制。采用扫描电镜、透射电镜和X射线衍射仪检测磁粉的表面形貌、内部结构和晶格畸变,采用B-H分析仪检测磁粉芯的动态磁性能。结果表明,改进的制备工艺能够有效降低磁粉芯的损耗,提高磁导率和频率应用范围。延长非晶粉末的球磨时间能够降低磁粉芯的磁滞损耗和涡流损耗,最佳的球磨时间为8h。通过对比磁粉的晶格畸变,发现通过改进工艺制备的磁粉的晶格畸变相对较小,该工艺提高磁性能的原因在于磁粉残余内应力的有效释放。     

Soft Magnetic Properties of Fe-5wt%Al Alloy

In this investigation, a new soft magnetic material (iron with 5 wt% aluminum) has been developed using powder metallurgy processing. The microstructure and the magnetic properties of this new P/M alloy have been characterized at both room and elevated temperatures (up to 500°C). The influence of post-sintering (after initial processing) on the porosity and magnetic properties of this material has also been examined.

Test results show that the room temperature soft magnetic properties of this alloy are comparable to other commercially available soft magnetic materials such as P/M pure Fe, Fe-Si, Fe-P, etc. Post-sintering at 1316°C resulted in significant grain growth and lower porosity with more rounded pore morphology and improved the magnetic properties. While the magnetic induction of the alloy was essentially constant from room temperature to 500°C, the coercivity of the material decreased significantly at elevated temperature. This new P/M alloy may be a suitable soft magnetic material for high temperature (up to 500°C) applications.     

Fe-Si-Al复合磁粉芯制备工艺的研究

模压成型制备Fe-Si-Al复合磁粉芯,研究了热处理条件及绝缘包覆处理对复合磁粉芯磁性能的影响.实验结果表明:压制后的退火处理能够有效地提高Fe-Si-Al磁粉芯的磁性能;增加退火温度能够提高样品的有效磁导率,减少磁滞损耗;过高的退火温度(＞660℃) 能够恶化粒子间的绝缘层,降低磁特性;Fe-Si-Al磁粉芯的最佳退...     

Soft Magnetic Properties of Fe - (1 wt.%) Al Alloy Processed by Powder Metallurgy

A soft magnetic material (iron with 1 wt.% aluminum) has been developed using a powder metallurgy processing route. The addition of aluminum in iron has resulted in an alloy with significant grain growth during sintering and correspondingly superior magnetic properties characterized by a low coercivity (H_c≈0.9 Oe), a relatively high permeability (μ_max ≈ 5000) and a high saturated magnetic induction (B_s ≈ 13 kG at 8 Oe) after sintering at 1482°C for 12 hours. The effects of sintering time and temperature on the magnetic properties of this alloy have also been examined.     

铁硅铝磁粉芯的磁特性研究

采用球磨制粉和模压成型方法制备了铁硅铝磁粉芯,并研究了其频率特性和直流叠加特性。结果表明,在测量的频率范围内（1～500kHz）,铁硅铝磁粉芯有效磁导率基本保持不变,而品质因数随频率的增加而增大,达到峰值后缓慢下降。在相同频率下,随着粉料粒度的减小,磁粉芯的有效磁导率降低,品质因数增加。铁硅铝磁粉芯具有良好的直流叠加特性,当直流偏磁场强度为1000e时,其有效磁导率变化率小于50％,且减小磁粉粒度可改善磁粉芯的直流叠加特性。     

FeNi/Glass Soft Magnetic Composites with High Magnetic Properties

FeNi/glass composites with 0 wt%,1 wt%, and 2 wt% glass content are produced, and their soft magnetic properties are systematically studied. The scanning electron microscope (SEM) results indicate that the FeNi particles are surrounded by glass powder. With the addition of glass powder, the saturation magnetization of the FeNi/glass composites decreases from 170 to 158 emu/g, and the effective permeability decreases from 56.1 to 39.1. With the increase of glass content, the imaginary part μ″ is reduced, indicating that the eddy current loss or excess loss is reduced at high frequency. The magnetic loss measurement results show that the addition of glass powder greatly reduces the eddy current loss. Furthermore, the FeNi/glass composite core with 2 wt% glass content has moderate permeability, higher quality factor Q, and better DC bias characteristics than other cores. The results show that the ideal glass powder content can improve the magnetic properties of FeNi composite materials, and glass powder can be used as an insulator in soft magnetic composites (SCMs).

     

制备工艺对非晶磁粉芯磁性能的影响

研究了粒度配比和绝缘剂对非晶磁粉芯性能的影响。改变非晶粉末的粒度配比，研究了非晶磁粉芯的压制密度、磁导率、损耗以及直流偏置能力等性能的变化。结果表明，粒度配比为-140至+170目占10%，-170至+200目占30%；-200至+350目占30%，-350至+1000目占30%能提高非晶磁粉芯的压制密度，从而提高直流偏置能力和降低磁损耗；使用不同的绝缘剂封装非晶磁粉芯时，使用磷酸溶液比使用水玻璃溶液能更有效地降低磁损耗和提高直流偏置能力；低熔点玻璃粉在非晶磁粉芯中不仅起绝缘剂作用，还起粘结剂作用。使用废旧非晶铁芯制备的非晶磁粉芯与使用新铁硅硼合金制备的非晶磁粉芯，其磁性能没有明显的不同。     

二次酸化表面改性制备高体积电阻率FeSiCr合金磁粉芯

FeSiCr合金粉末具有强耐腐蚀性,通过弱酸磷化的方式无法有效改善FeSiCr合金磁粉芯的绝缘性。本研究以盐酸乙醇溶液作为二次酸化剂,对磷化(一次酸化)的FeSiCr合金粉末表面改性,制备高体积电阻率FeSiCr合金磁粉芯。通过扫描电镜、LCR电桥和超高阻微电流测试仪分析盐酸乙醇溶液浓度对FeSiCr合金粉体微观形貌,交流磁学性和体积电阻率的影响。研究结果表明,二次酸化法表面改性FeSiCr合金粉末,可有效增加合金磁粉芯体积电阻率,降低高频损耗因子。其复数磁导率实部随盐酸乙醇溶液浓度增加而降低。当盐酸乙醇溶液浓度为5.0wt.%,FeSiCr合金磁粉芯体积电阻率可达7.85×10⁸Ω·m,在1MHz测试条件下损耗因子为0.053Ω/μH。     

Microstructure and Magnetic Properties of Soft Magnetic Composites with Silicate Glass Insulation Layers

In this study, a new soft magnetic composite (SMC) material design scheme was put forward. According to this design scheme, SMC with silicate glass insulation layers was prepared by powder metallurgy with nanometer glass powder and micron iron powder. It can be annealed at high temperature for reducing residual stress. The magnetic properties were good. The maximum permeability, saturation magnetic induction, residual magnetic flux density and coercivity were 467, 1.47 T, 1.25 T and 394 A/m, respectively. The core loss versus alternating magnetic field frequency showed linear growth. The core loss was 4.4 W/kg at an induction level of 1 T, 50 Hz.