绝缘剂用量对FeSiAl磁粉芯性能影响的研究

探讨了不同绝缘剂用量对磁粉芯综合性能的影响，实验选用粒径为100gm以下机械破碎制备的合金粉末，绝缘剂用量为1％～5％（质量分数）。绝缘剂用量控制在2％以内，粉芯样品有较高的磁导率，可达到130左右；当用量加到3％时，样品频率特性较好，在f=50kHz、Bm=100mT的测试条件下损耗为550mW／cm^3，具有良好的综合性能。     

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。     

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.     

粉末冶金法制备Fe-Si-Ni磁粉芯及其磁性能

采用熔炼-铸锭-球磨的方法制备了Fe-Si-Ni粉末,经过预退火热处理、绝缘包覆后将粉末压制成磁粉芯,并对成型后的磁粉芯进行去应力退火处理。对Fe-Si-Ni粉末及磁粉芯的性能系统地进行了检测分析。结果显示:经过预退火处理后的Fe-Si-Ni粉末具有较高的饱和磁化强度(Ms)。Fe-Si-Ni磁粉芯的有效磁导率(μe)在10~1000kHz的频率范围内变化很小,且随着Ni含量和退火温度的升高而增大。Fe-Si-Ni磁粉芯有着良好的直流叠加特性(dc-bias),当Ni≥5wt.%时,尽管磁导率百分比随着退火温度的升高逐渐减小,然而在外加直流磁场强度为50Oe时,磁粉芯的磁导率百分比均在70%以上。品质因数(Q)随着Ni含量和退火温度的升高逐渐增大,磁芯损耗随着Ni含量和退火温度的升高而减小。当Ni=8wt.%,退火温度为750℃时,磁粉芯在50kHz,50mT下的磁芯损耗有最小值312mW/cm3。     

Fe73．5Cu1Nb3Si13．5B9纳米晶磁粉芯磁性能研究

用Fe73.5Cu1Nb3Si13.5B9纳米晶粉体,加入一定量的塑化剂,通过模压成型方法制备磁粉芯.实验结果表明,在一定粒度范围内,磁导率μ随粉体粒度增大而增大,品质因数Q,随着粒度的增大而减小,且在一定频率范围内,μ呈现良好的频率稳定性;塑化剂质量百分含量α越大,μ越小.当α=6.5%时,μ达到最大值31.8.0～300kHz范围内,α与Q成反比;300～1000kHz范围内,α与Q成正比例关系;磁导率μ随着成型压力的增加而提高,相反,压力越大,Q值越小;磁导率随着磁粉芯测试温度的提高逐渐减小,0≤f≤700kHz范围内,温度升高,Q降低,700kHz≤f≤1000kHz范围内时,温度升高,Q值升高;随退火温度的增加,μ和Q均呈现先增大后减小的趋势.     

Fe-Ni基纳米晶软磁粉芯磁性能研究

采用模压成型成功制备了Fe-Ni基纳米晶磁粉芯。并研究了热处理温度和时间、纳米晶粉体的粒度、成型压力等对其磁性能的影响和其温度稳定性和频率稳定性。结果表明,当100～900℃内退火,随着温度升高,μe和Q值都呈先增后减,600℃时μe达到最大值31.5,其最佳退火时间为2h。成型压力和纳米晶粉体粒度越大,μe越大,Q值越小。在100～1000kHz内,磁粉芯具有较好的频率稳定性。在25～100℃内,随着温度的升高,μe逐渐下降,其中25～40℃内,μe变化敏感,温度系数αμ为-1.95×10-3℃-1,而高于40℃时,其温度系数αμ仅为-2.48×10-4℃-1。     

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。     

纳米晶Fe73.5Cu1Nb3Si13.5B9磁粉芯的磁性能研究

利用球磨纳米晶Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９合金得到的粉末压制成磁粉芯,研究其磁性。结果表明,在测量的频率范围内（１ｋＨｚ－１００ｋＨｚ）,该粉芯的磁导率几乎不随频率变化的而变化;粉芯的品质因数Ｑ随的增加而增加,在较高频率时有着比坡莫合金粉芯还要高的值,具有应用价值。推导出磁粉芯的静态磁导率的表达式发现分芯的磁导率与磁粉芯的密度有着密切的密度愈大,磁粉芯的静态磁导率愈高。     

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...     

Fe—47wt%Ni纳米晶粉芯磁谱及其压力效应

用蒸发冷凝法，制备成不同平均粒径的Ｆｅ－４７ｗｔ％／Ｎｉ纳米晶粉。将其压成小圆环，测其室温磁谱。结果表明，Ｆｅ４７ｗｔ％Ｎｉ纳主晶粉芯具有较好的高频特性。在（１－３００）ＭＨｚ频率范围内，其复数磁导率实部μ１〉１００，虚部μ２〈２０，损耗解正切ｔｇδ〈０．１，共振频率ｆｒ〉３００ＭＨｚ。当１ＭＨｚ〉ｆ〉４００ＭＨｚ时，μ２及ｔｇδ激剧上升。在（１－３００ＭＨｚ）范围，形成一个很宽的通频带。它有可能     

Enhancing soft magnetic properties of FeSiBNbCu nanocrystalline powder cores by coating ZrO2 insulation layer

The insulation coating plays a crucial role in minimizing core loss (P_cv) in soft magnetic powder cores (SMPCs). In this work, we prepared ZrO₂ coating layer on FeSiBNbCu spherical powder by the hydrolysis-precipitation method and investigated the magnetic properties of the FeSiBNbCu@ZrO₂ nanocrystalline SMPCs. ZrO₂ coating layer were successfully fabricated on the powder by adding a proper amount of K₂ZrF₆ in alkaline ethyl alcohol solution. The micromorphology and chemical structure of the ZrO₂ coating layer on the surface of FeSiBNbCu nanocrystalline powder, as well as the conversion mechanisms, has been investigated. The presence of the ZrO₂ coating reduces the P_cv by significantly lowers eddy loss (P_e) of the nanocrystalline SMPCs, meanwhile improves DC bias performance and slightly decreases their permeability. When the additive amount of K₂ZrF₆ is 1.0 wt%, the nanocrystalline SMPCs has best comprehensive soft magnetic properties, including stable effective permeability (μ_e) of 57.8 up to 1 MHz, excellent DC bias performance of 59.3 % at a bias field of 100 Oe, and the lowest P_cv of 194.7 mW/cm³ at a frequency (f) of 150 kHz and maximum magnetic induction (B_m) of 50 mT.     

纳米晶合金粉芯的超重力渗流制备及磁性能

为了探索粉芯的新制备工艺,以Fe73.5Cu₁Nb₃Si13.5B₉纳米晶合金铁芯为原料,使用机械破碎法制粉,并采用超重力渗流工艺制备了7种不同粒度配比的纳米晶合金粉芯,借助SEM、XRD、VSM分别对纳米晶粉末的形貌、结构和磁性能进行了表征,研究了粉末粒度配比对纳米晶合金粉芯的形貌、密度、有效磁导率、损耗及品质因数的影响。结果表明,机械破碎法制得的粉末虽带尖角,但矫顽力低,利用超重力渗流工艺制备的粉芯其粉末表面基本被树脂完全包覆。同时,通过适当的粉末粒度匹配,发现性能最佳粉芯的粉末粒度配比为:100~200目占60%,200~400目占20%,400~1 000目占20%。该种粉芯的密度为4.46 gcm³,在100~3 000 kHz频率范围内有效磁导率比较稳定,且在3 000 kHz时为28.2。当设定磁感应强度为20 mT,频率为500 kHz时,其损耗为99.1 W/kg。另外,根据实验结果可知,该工艺能够制备出频率在MHz以上具有较低损耗的粉芯。     

Evolution of magnetic domain structure and magnetic properties of Fe-based nanocrystalline powder cores during transverse magnetic field annealing

In this work, transverse magnetic field annealing (TA) was performed to FeSiBNbCu nanocrystalline powder cores (NPCs), and the magnetic properties, microstructure, and magnetic domain structure were in detail studied comparing with those after normal annealing (NA), and the mechanism of the improvement of soft magnetic properties by TA was elucidated. The experimental results show that the core loss of the sample is reduced by 14 % and the coercivity is reduced by 38 % after TA at 450 °C compared to the NA sample. The direct current bias performance of the TA sample is maintained at 67 % under a 100 Oe bias field. TA optimizes the soft magnetic properties of NPCs by optimizing the domain structure, reducing the formation of micro-vortex dots and broadening the size of the domain. These results can provide a good guide for optimizing the performance of NPCs with low core loss at high frequency.     

Fe78Si13B9/铁氧体复合材料磁粉芯制备及其软磁性能

用Mn-Zn铁氧体溶胶对非晶Fe78Si13B9粉体包覆,模压成型制备了复合磁粉芯,并研究了复合材料磁粉芯的软磁性能.实验结果表明,铁氧体粉体在500℃×2h的热处理条件下逐渐生成,并在非晶Fe78Si13B9颗粒表面较好包覆;铁氧体溶胶的加入,大大提高了非晶Fe78Si13B9磁粉芯的品质因数Q值.当铁氧体溶胶量为7%、30℃的测试温度时,Fe78Si13B9/铁氧体复合材料磁粉芯的磁导率在1MHz时达到最大值32,Q值高达23.     

Fe/Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9纳米晶磁粉芯研究

采用Fe粉复合FeCuNbSiB纳米晶粉体制备了磁粉芯,并讨论了退火温度、Fe粉复合量、纳米晶粉体粒度以及绝缘剂等对磁粉芯磁性能的影响.结果表明,在200～350℃和350～400℃内退火,随着温度的升高,μ_e均呈先增大后减小,375℃时达到最佳;当复合Fe粉后,发现其软磁性能得到了明显改善, Fe粉量为40%时,μ_e达到最大,且在100kHz～1MHz内,频率稳定性良好,其中心频率在500kHz附近,并随Fe粉量的增加而向低频发生偏移.纳米晶粉体的粒度越大,磁粉芯的磁性能越好;粉体粒度为100～200目时,其μ_e达到最大.当375℃退火,由有机绝缘剂、40%(质量分数)Fe粉、100～200目纳米晶粉制备的磁粉芯,其μ_e达52.72、损耗Pu为0.01317J/m~3、Bs为3.92×10~(-3)T、Br=6.48×10~(-5)T、H_c为1.28A/m.     

软磁Fe-Si-Al磁粉芯性能研究

研究了绝缘包覆、压制成型、退火处理对软磁Fe-Si-Al磁粉芯性能的影响.采用扫描电镜,金相显微镜,B-H分析仪和万能材料试验机检测样品的内部结构、形貌、磁性能和力学性能.研究结果表明,添加绝缘剂能够有效的降低磁粉芯的涡流损耗;增大成型压力可以提高磁粉芯的压渍强度、密度、磁导率,降低损耗和矫顽力,最佳成型压力为1800MPa;压制后的退火处理是保证磁粉芯具有较好磁性能的关键,提高热处理温度可以有效的提高磁导率,降低磁滞损耗,但过高的热处理温度会使磁粉芯的磁性能恶化,最佳的退火温度为660℃.     

Enhanced high frequency properties of FeSiBPC amorphous soft magnetic powder cores with novel insulating layer

Fe-based amorphous magnetic powder cores (AMPCs) with excellent comprehensive properties were successfully fabricated via using the uniform double insulating layer core-shell structured FeSiBPC/Fe₃O₄@Epoxy resin (EP). The effects of the in-situ hydrothermal oxidized time on the magnetic properties of the AMPCs have been systematically investigated on the basis of the growth mechanism of the insulating layer of spherical amorphous powder in alkaline environment. The hydrothermal oxidation process could well ensure the uniformity of the oxide layer composed of Fe₃O₄ nanoparticle. The evolution of the insulating layer is a process of homogeneous nucleation and growth at different hydrothermal oxidation time. After 10 h of hydrothermal oxidation, a thin and dense layer composed of Fe₃O₄ nanoparticle was formed on the surface of the amorphous powder. As a consequent, the FeSiBPC AMPCs exhibit excellent performance such as stable effective permeability of 49.5 at 2 MHz, a very low core loss of 187 mW/cm³ at 100 kHz@0.05 T and high-quality factor of 160 at 600 kHz. The results indicate that the thickness of the Fe₃O₄ insulating layer can be completely controlled via the reaction parameters, and can effectively suppress the eddy current loss, which is promising for high-frequency electromagnetic systems.     

纳米晶软磁材料的磁性能

介绍了纳米晶软磁材料所具有的独特结构和优异的磁性能。从纳米晶软磁材料的微观组织结构和宏观磁特性紧密相关的角度,探讨了铁基纳米晶合金的结构与磁性之间的依赖关系。