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。     

气流破碎Fe-Si-B非晶磁粉芯的制备与磁性能研究

采用粉末冶金技术,以气流破碎Fe78Si9B13非晶粉末为原料制备非晶磁粉芯。利用差示扫描量热仪、X射线衍射仪和B-H分析仪测试样品的热力学参数、相组成和磁性能,研究绝缘剂添加量和退火温度对磁粉芯磁性能的影响。结果表明,增加绝缘剂添加量可以降低磁粉芯的涡流损耗,但绝缘剂过多会降低磁导率和品质因数;去应力退火处理能有效提高磁导率和品质因数,降低磁损耗,但退火温度过高会使非晶磁粉芯晶化,导致磁性能的下降,最佳退火温度为400℃。     

绝缘包覆工艺对Fe78Si9B13非晶磁粉芯磁性能影响研究

实验以气流破碎的Fe78Si9B13非晶粉末为原料制备磁粉芯。采用扫描电镜和B-H分析仪研究了绝缘包覆工艺过程中添加钝化剂以及粘结剂和绝缘剂的添加量对磁粉芯磁性能的影响。结果表明添加钝化剂可以有效地提高磁粉芯的频率特性,降低磁损耗,增大品质因数;增加绝缘剂的添加量可以降低磁粉芯的涡流损耗,但过多的绝缘剂又会降低其磁导率;最佳的粘结剂添加量为3.5%。     

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.     

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。     

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。     

软磁合金粉末特性对金属软磁粉芯的影响

软磁合金粉末作为制备金属软磁粉芯的原材料,是决定磁粉芯性能的关键因素之一。本文综述了软磁合金粉末的合金成分、形貌、粒度以及粉末纯度对软磁粉芯性能的影响。分析结果表明,铁硅铝磁粉芯具有最佳性价比,采用气雾化法生产的球形粉末具有最佳的软磁特性,软磁粉末越细,纯度越高,所制备的磁粉芯软磁性能越好。     

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.     

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。     

Fe基纳米晶／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Fe73.5Cu1Nb3Si13.5B9纳米晶包覆,模压成型制备复合磁粉芯,并研究了铁氧体溶胶量、热处理工艺及测试温度等因素对复合材料磁粉芯软磁性能的影响.实验结果表明,随着铁氧体溶胶量的增加,磁粉芯的磁导率减小,而Q值却随铁氧体溶胶量的增加有微小的增大.复合材料磁粉芯在热处理工艺为2h,500℃时,测试频率为500kHz,磁导率达到最大值.复合磁粉芯的品质因数Q值在200～1000kHz频段中,具有波动性,Q值在500kHz时达到51.测试温度对复合磁粉芯的磁导率和品质因数均有影响,测试温度从30℃升高到80℃时,磁导率从60.1降低到58.4,变化率为2.8%,而品质因数从59下降到54.     

非晶FeSiB粉体/IIR复合材料的电磁屏蔽性能研究

以丁基橡胶为基体,Fe_(78)Si_(13)B_6非晶粉体为主要屏蔽剂,利用模压成型法制备了Fe_(78)Si_(13)B_6/丁基橡胶电磁屏蔽复合材料,采用矢量网络分析仪对其屏蔽性能进行了测试.结果表明,在0.03～6000MHz范围内,Fe_(78)Si_(13)B_6非晶粉体具有良好的吸收损耗效果;粉体含量、粒度、试样厚度均显著影响材料的屏蔽性能;试样经过180℃×6h的热处理后,屏蔽性能达到最佳.     

Fe78Si9B13非晶合金磁芯封装及其软磁性能

研究了Fe78Si9B13非晶合金磁芯进行环氧封装及封装后对非晶合金磁芯软磁性能的影响。结果表明对磁芯进行环氧封装,有效改善磁芯的机械强度同时,能改善带材表面的平整度,在带材表面形成一层绝缘层,显著降低了非晶合金磁芯高频下的损耗值,封装后的非晶合金磁芯在Bm=1T,f=1kHz下,损耗值比封装前下降了14%。综合考虑机械强度大小、磁化难易、损耗高低等因素,封装胶浓度为2%时封装效果最佳。     

Effects of gas nitridation on microstructures and magnetic properties of Fe3N/Fe soft magnetic composites

Journal of Materials Science: Materials in Electronics - Fe3N/Fe soft magnetic composites (SMCs) are a kind of promising materials with excellent magnetic properties. In this work, Fe3N/Fe...     

Fe_3O_4/BSA纳米磁性复合颗粒的磁响应性能

利用化学液相共沉淀法制备出不同尺寸、具有超顺磁性的纳米磁性Fe3O4/BSA颗粒,经分散后包覆蛋白使其具备良好的生物兼容性,该颗粒可长期、稳定地分散在溶液中。在外加交变磁场(414kA/m,50Hz)下纪录不同颗粒的浊度变化率,并利用光透射性可即时测得介质中浑浊程度与时间的关系,结合浊度-浓度拟合曲线,计算出在外加磁场作用下,磁性纳米复合颗粒对外加磁场的响应程度,半定量计算出相同时间下不同尺寸的微粒吸附在管壁上的质量百分比。结果显示,稳定在介质中的纳米磁性颗粒在外加磁场后,磁响应性随颗粒尺寸增大而增大,颗粒大小分别为10、108和210nm,所对应的磁响应性分别为6%、10%和12%;在外加磁场30s后,该磁性纳米复合颗粒在管壁附着的质量百分比分别为39.9%、70.4%及86.7%。     

Development of P/M Fe–P soft magnetic materials

Phosphorous is treated as an impurity in conventional steels owing to segregation of phosphorous and formation of brittle phosphides along the grain boundaries. It is responsible for cold and hot shortness in wrought steels. In conventional powder metallurgy, involving compaction and sintering, high phosphorous content (up to 0·7%) in Fe-based alloys exhibit attractive set of mechanical and magnetic properties. These powder-processed alloys suffer from increasing volumetric shrinkage during sintering as phosphorous is increased beyond 0·6%. Thus both cast as well as conventional powder metallurgy routes have their own limitations in dealing with iron?Cphosphorous alloys. Hot-powder forging was used in the present investigation for the development of high-density soft magnetic materials containing 0·3?C0·8% phosphorous to overcome these difficulties. It was observed that phosphorous addition improves the final density of the resulting product. It was further observed that hot-forged iron?Cphosphorous alloys have excellent hot/cold workability and could be easily shaped to thin strips (0·5?C1·0?mm thick) and wires (0·5?C1·0?mm diameter). The powder hot-forged alloys were characterized in terms of microstructure, porosity content/densification, hardness, soft magnetic properties and electrical resistivity. Magnetic properties such as coercivity 0·35?C1·24?Oe, saturation magnetization 14145?C17490 G and retentivity 6402?C10836 G were observed. The obtained results were discussed based on the microstructures evolved.     

Structure and magnetic properties of ZrO2-coated Fe powders and Fe/ZrO2 soft magnetic composites

Fe particles were coated with ZrO₂ nanopowders using mechanical milling method combined with high temperature recovery annealing process. The effect of milling time on particle size, phase structure and magnetic properties of the core-shell structure powders was studied. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD) revealed that the surfaces of the composite powders comprised thin and uniform layers of ZrO₂ insulating powders after milling. Also, the SEM images showed the morphology of micro-cellular structured compacts with cell-body of Fe particles and indicated that Fe particles were well separated and insulated by thin ZrO₂ layers. The Fe/ZrO₂ soft magnetic composites displayed much higher electrical resistivity, lower core loss than that of the pure Fe powder cores without ZrO₂ layers at medium and high frequencies. The preparation method of ZrO₂-insulated Fe powders provides a promising method to reduce the core loss and improve the magnetic properties for soft magnetic composite materials.     

Self-nanoscaling of the soft magnetic phase in bulk SmCo/Fe nanocomposite magnets

Fabrication of bulk nanocomposite materials, which contain a magnetically hard phase and a magnetically soft phase with desired nanoscale morphology and composition distribution has proven to be challenging. Here we demonstrate that SmCo/Fe(Co) hard/soft nanocomposite materials can be produced by distributing the soft magnetic α-Fe(Co) phase particles homogenously in a hard magnetic SmCo phase matrix through a combination of high-energy ball milling and a warm compaction. Severe plastic deformation during the ball milling results in nanoscaling of the soft phase with size reduction from micrometers to ~15 nm. Up to 35% of the soft phase can be incorporated into the composites without coarsening. This process produces fully dense bulk isotropic nanocomposite materials with remarkable energy-product enhancement (up to 300%) owing to effective inter-phase exchange coupling.     

软磁复合材料铁芯电机特性的仿真研究

为了发挥软磁复合材料的高电阻率,低损耗,易于再利用的特点,仿真模拟将其应用在永磁电机的铁芯上.以12槽4极直流电机为仿真对象,把三维计算问题转化成二维模型,用JMAG软件对电机进行建模,阐述SMC与硅钢片铁芯差异,先用两种材料进行仿真,结果说明只靠替换铁芯材料对电机性能改进并不会产生很大改善,改进模型,得出不同延伸高度铁芯延伸长度增加引起的电流和转矩特性与功率变化的关系.利用所建模型将Somaloy500的软磁复合材料与50CS800的硅钢片制备的铁芯进行模拟实验,结果表明:相同条件下软磁复合材料铁芯的效率要更高一些.最低转速时效率增加5%,最高转速时效率增加10%;软磁复合材料铁芯模型抑制电流输出,各向同性的优势明显.结论为SMC材料在低转速电机的开发中依旧能够发挥优势,实现电机性能的提高.