注射成形法制取各向异性粘结NdFeB磁体的研究

研究了磁粉粒度、取向磁场强度、取向时间及装载量对注射成形各向异性粘结NdFeB磁体性能的影响，并分析了其原因。结果表明：NdFeB磁粉粒径太粉末或太细均不利于磁体性能的提高，其最佳粒径范围是60μm～100μm；随着取向磁场强度的逐渐增加，磁体剩磁Br及矫顽力bHc增加较大但其内禀矫顽固力jHc则基本不变；与此同时为保证磁粉取向完全，磁场取向时间必须大于5g。在此基础上，通过实验找出了最佳的装载量并制备出最大磁能积（BH）max和抗压强度σb分别为99kJ/m^3及125MPa的高性能注射成形各向异性粘结NdFeB磁体。     

注射成型粘结NdFeB磁体的研发进展

简述注射成型粘结NdFeB磁体的制备工艺，分析了磁粉、粘结剂、取向磁场和工艺参数对注射成型粘结NdFeB磁体磁性能的影响以及该磁体的性能状况，并概述了粘结NdFeB磁体的产业发展及其应用领域，最后提出注射成型粘结NdFeB磁体的开发重点。     

各向异性Nd-Fe-B系粘结磁体及其在马达上的应用

近年来对于微型马达的要求日益提高 ,强烈要求开发磁特性更高的磁体。ＨＤＤＲ法生产的Ｎｄ Ｆｅ Ｂ系各向异性磁体可制成 1 2ＭＡ/ｍ以上的高矫顽力型 ,其热稳定性也能达到各向同性磁体的水平。但是 ,高矫顽力型ＨＤＤＲ粉末的取向和充磁都很困难。为了克服这种困难 ,开发了高矫顽力型ＨＤＤＲ磁粉轴向取向的挠性粘结磁体以及小型马达用环状磁体成形新技术。各向同性Ｎｄ Ｆｅ Ｂ系粘结磁体之所以在微型马达上获得普及 ,正是由于它的磁特性不受环形磁体直径大小等形状因素的影响 ,因此研究了各向异性ＨＤＤＲ磁粉制作的各向异性粘结磁体在…     

注射成形法制备高性能粘结NdFeB磁体

利用新研制的磁场注射成形机,研究了磁粉表面改性处理、取向磁场强度及装载量对注射成形各向异性粘结NdFeB磁体性能的影响.结果表明:磁粉经硅烷改性后,可在其表面形成一层抗氧化膜,其氧化质量增加率由2.3%下降至0.35%,相应制得的粘结磁体最大磁能积及抗压强度分别提高了17.8%和35.9%;而随着取向磁场强度的增加,磁体剩磁Br及矫顽力bHc均有较大幅度的增加,但其内禀矫顽力iHc则基本不变;同时,通过实验得出了最佳的装载量为65%(体积分数),并制备了最大磁能积(BH)max及抗压强度σbb分别为99 KJ/m3和125 MPa的注射成形粘结NdFeB磁体.     

晶界扩散型(Tb,Nd)FeB磁体的结构与性能

采用磁控溅射方法在烧结钕铁硼磁体表面沉积一层Tb镀层,然后进行晶界扩散热处理,制备出晶界扩散型(Tb,Nd) FeB磁体.通过扫描电子显微镜、电子探针分析仪和磁滞回线测量仪分析了晶界扩散前后磁体的微观结构与磁性能.结果 表明:与NdFe磁体相比,采用晶界扩散方法制备的(Tb,Nd) Fe磁体具有更宽的晶界相,且晶界相在主相晶粒周围连续分布,起到了去磁耦合作用.并且分布在主相晶粒表层的重稀土元素Tb形成了磁晶各向异性场更高的(Nd,Tb)2 Fe14B相.(Tb,Nd) FeB磁体的内禀矫顽力Hcj得到显著提升,其Hcj由NdFe磁体的15.98 kOe提高到23.78 kOe.     

各向异性钕系粘结磁体

各向异性钕系粘结磁体１９９３年末美国通用汽车公司（ＧＭ）和日本住友特殊金属公司、三菱公司三家共同订立了磁各向异性Ｎｄ－Ｆｅ－Ｂ系粘结磁体互换专利协议。因为在钕系粘结磁体方面，住友公司拥有基本成分专利，ＧＭ公司有粘结磁体专利，三菱公司持有钕系粘结磁体各...     

纳米晶复合永磁材料各向异性的研究进展

具有优良磁性能的各向异性R-Fe-B（R：稀土元素）粘结磁体受到广泛的关注,使用各向异性熔体快淬带制备各向异性粘结磁体工艺较为简单。本文介绍了熔体快淬带织构的形成机理和研究进展,着重于微观结构、添加元素以及处理工艺的影响。     

粘结钕磁体的最新发展

粘结钕磁体的最新发展１．ＨＤＤＲ各向异性粘结磁体：各向异性ＨＤＤＲ（氢化－歧化－脱氢－再结合）材料的发现是高性能粘结钕磁体发展中的一个突出进步。合金锭首先经过氢化，随后的歧化处理使Ｎｄ２Ｆｅ１４Ｂ粗晶粒转变成Ｆｅ、Ｆｅ２Ｂ和ＮｄＨ２混合物，在脱氢阶段...     

各向异性磁粉的磁场取向行为

粘结磁体可由磁粉与树脂的混合粉末经压缩成形、注射成形或挤压成形制得。采用压缩成形（冲压成形）时,成形体密度亦即磁粉的体积填充率最高,因此,可得到磁特性比其它方法更高的各向同性粘结磁体。在生产各向异性粘结磁体时,如果在冲压成形时将混合粉末的温度加热到树脂粘结剂的熔点以上,由于粘结剂熔融而使得磁粉之间的摩擦阻力减小,亦即润滑性增大,因而改善了压缩时的压力传递性,使得成形体中的磁粉填充率提高、磁粉取向度也提高,能够制得具有高磁特性的各向异性粘结磁体。但是,有关取向磁场条件和冲压成形时混合物的温度,对于…     

耐热性Nd-Fe-B各向异性粘结磁体

用ＨＤＤＲ处理法生产的ＮｄＦｅＢ各向异性磁粉制作的粘结磁体,较之传统ＮｄＦｅＢ各向同性粘结磁体（ＭＱ粘结体）,磁特性高（（ＢＨ）ｍａｘ约１６０ｋＪ／ｍ３）。但各向异性磁粉的耐热性差,其矫顽力的温度系数（ａＨ）为－０．５～－０．６％／Ｋ,各向同性磁粉为－０．４％／Ｋ。为了改善各向异性ＮｄＦｅＢ粘结磁体的耐热性,研究了利用含有挥发性成分的树脂作为粘结剂的效果,探讨了挥发性树脂的配合方法对于粘结磁体力学强度的影响。研究用的ＮｄＦｅＢ各向异性磁粉是用ＨＤＤＲ处理法制得的Ｎｄ１３。０Ｆｅ６８．７Ｃｉ１０．…     

Magnequench magnets status overview

The advent of neodymium-iron-boron materials having excellent magnetic properties and potential economic advantages has initiated a new era in permanent magnet technology. One method of making these magnets is by the rapid solidification process. It is typically carried out by melt spinning, which produces a highly stable, dmagnetically hard microstructure powder, directly from the melt. This can be used for bonded magnet applications. Alternatively, this powder can be hot pressed to produce fully dense isotropic magnets with energy products up to 15 MGOe. Anisotropic magnets with energy products ranging up to 50 MGOe can be produced by thermomechanical orientation or hot deformation process. Current processing and properties of Magnequench (General Motors) materials are reviewed, das well as the applications and advances of these materials. The advances include high-temperature bonded magnet and high-energy product anisotropic bonded and fully dense magnets.     

Epoxy resin effect on anisotropic Nd-Fe-B rubber-bonded magnets performance

A novel anisotropic Nd-Fe-B flexible bonded magnet with epoxy resin lubricant was prepared by the two-step method to enhance its performance. Temperature characteristics of epoxy resin and its effect on magnetic properties and preparation of anisotropic Nd-Fe-B flexible bonded magnets were investigated and optimized. DOA of aligned flexible bonded magnets with epoxy resin lubricant increases significantly due to epoxy resin lower viscosity and subsequent better powder particles lubrication at a certain aligning temperature. Meanwhile, H_irr decreases sharply due to improved oxidation resistance of epoxy resin fully encapsulating magnetic powder during magnetic alignment process. Utilizing 1 wt% optimized encapsulating epoxy resin and heating unaligned flexible bonded magnets to 80 °C for 30 min during magnetic alignment resulted in the largest Δ(BH)_max and ΔDOA. Δ(BH)_max increased to over 126% along with ΔDOA increase to over 75%, much higher compared with unaligned flexible bonded magnets prepared exclusively by calendering.     

Magnetic properties and thermal stability of anisotropic bonded Nd-Fe-B magnets by warm compaction

Anisotropic bonded magnets were prepared by warm compaction using anisotropic Nd-Fe-B powder. The forming process, magnetic properties, and temperature stability were studied. The results indicate that the optimal temperature of the process, which was decided by the viscosity of the binders, was 110℃. With increasing pressure, the density of the magnets increased. When the pressure was above 700 MPa, the powder particles were destroyed and the magnetic properties decreased. The magnetic properties of the anisotropic bonded magnets were as follows: remanence Br = 0.98 T, intrinsic coercivity iHc=1361 kA/m, and maximum energy product BHmax = 166 kJ/m3. The magnets had excellent thermal stability because of the high coercivity and good squareness of demagnetization curves. The flux density of the magnets was 35% higher than that of isotropic bonded Nd-Fe-B magnets at 120℃ for 1000 h. The flux density of the bonded magnets showed little change with regard to temperature.     

粘结剂和添加剂对注射成型各向异性粘结NdFeB磁体的影响(英文)

研究了在取向磁场下由HDDR磁粉注射成型的各向异性粘结NdFeB磁体,分析了粘结剂和添加剂对各向异性粘结NdFeB磁体的密度、磁性能以及抗压强度的影响.通过磁粉表面改性,磁粉的抗氧化性能以及磁体的磁性能都得到提高.比较了6种粘结剂对磁体性能的影响,从中得到比较理想的粘结剂,并且考察了抗氧剂以及润滑剂加入量对于磁体性能的影响.试验中,混炼温度为205～215 ℃,注射温度为265℃,注射压力为5～6 MPa,保压时间为5 s,模具加热温度为80℃.制得的磁体的性能为:Br=0.72 T,iHc=983 kA/m,(BH)max=75 kJ/m3.     

钛在自贡鸿鹤化工总厂联碱生产中的应用

简述了Ｓｍ２Ｆｅ（１７）Ｎｘ化合物的结构与内禀磁性能，着重回顾了Ｓｍ２Ｆｅ（１７）Ｎｘ永磁合金粉及其磁体的制备工艺发展现状，并展望了Ｓｍ２Ｆｅ（１７）Ｎｘ永磁体的发展前景。     

粘结钕铁硼磁体阴极电泳工艺研究

粘结NdFeB磁体极易被腐蚀,因而需要涂层保护.本文研究了粘结NdFeB磁体的阴极电泳工艺,主要是电泳电压,电泳时间,电泳时漆液温度以及涂层烘烤固化对涂层抗蚀性的影响.研究发现用合适的工艺参数所获得的涂层能够显著提高粘结NdFeB磁体的抗蚀性能.     

Preparation of isotropic Sm2Fe17Nx magnetic powders and their bonded magnets

The isotropic Sm2Fe17Nx magnetic powders were prepared by Hydrogenation-Disproportion-Desorption-Recombination (HDDR) process. The phase and microstructure evolutionary process of Sm-Fe alloy during the solidification, homogenization, HDDR and nitration processes were investigated by means of XRD, SEM, EDX and AFM. The results show that the homogeneous Sm2Fe17 alloy wassuccessfully obtained and the impurity phases and residual stress were well removed by heated at 1050 ℃ for 24 h. When heated at 800 ℃ for 1h in H2 of 0.1 Mpa, the alloy turns into SmHx and α-Fe with plenty of nanocrystals. After vacuumized at 800 ℃ for 2h the alloy recombines into Sm2Fe17 with a crystal grain size of about 85 nm.The lattice constant of the alloy increases and the expanding of the crystal cell reaches 6.28% after nitrified at 500 ℃ for 5 h. The magnetic property of isotropic bonded Sm2Fe17Nx magnets is Br=0.6704 T, Hcj = 1015 kA·m-1,( BH )max =73.7 kJ·m-3 with a density of 6.04 g·cm-3 .     

磁粉粒度分布和抗氧化剂对注射成型NdFeB粘结磁体性能的影响

本文研究了磁粉的粒度分布以及不同抗氧化剂的加入对注射成型NdFeB粘结磁体密度和磁性能的影响。结果表明，磁粉的粒度分布影响熔体的粘度，适当的粒度分布可以提高磁粉的松装密度和磁体的密度，获得高性能的粘结磁体；抗氧化剂的加入，很好地解决了NdFeB粘结磁体在湿热环境下易氧化生锈的问题，大大提高了磁体的抗氧化性能。     

Possible methods of recycling NdFeB-type sintered magnets using the HD/degassing process

With the rapid growth in the use of NdFeB-type magnets and with the growing environmental need to conserve both energy and raw materials, the recycling of these magnets is becoming an ever important issue. In this paper it is demonstrated that hydrogen could play a vital role in this process. Fully dense sintered NdFeB-type magnets have been subjected to the hydrogen decrepitation (HD) process. The resultant powder has been subsequently processed in one of two ways in order to produce permanent magnets. Firstly, the powder was subjected to a vacuum degassing treatment over a range of temperatures up to 1000 °C in order to produce powder that would be suitable for the production of anisotropic bonded or hot pressed magnets. Secondly, the HD-powder has been used to produce fully dense sintered magnets; in which case optimisation of the milling time, sintering temperature and time was carried out. The optimum degassing temperature for coercive powder was found to be 700 °C, giving powder with a remanence (Br) of 1350 mT (±50 mT) and an intrinsic coercivity (Hcj) of 750 kA m⁻¹ (±50 kA m⁻¹). The best sintered magnet was produced by very lightly milling the powder (30 min, roller ball mill), aligning, pressing and vacuum sintering at 1080 °C for 1 h. The magnetic properties of this magnet were: (BH)_max = 290 kJ m⁻³ (±5 kJ m⁻³), Br = 1240 mT (±50 mT) and Hcj = 830 kA m⁻¹ (±50 kA m⁻¹); representing decreases of 15%, 10% and 20%, respectively, from the properties of the initial magnet.