粘结NdFeB磁体制备的研究进展

综述了制备粘结NdFeB磁体的原料、成型工艺和防腐方法；概述了近年来在磁粉和磁体制备、磁体防护等方面的最新研究进展。认为随着粘结NdFeB磁体应用的不断扩展和需求的增长，其研究也将不断深入，产量也将不断扩大。     

快淬钕铁硼永磁合金及粘结磁体

综述了快淬钕铁硼磁粉、各向同性粘结钕铁硼磁体、各向异性钕铁硼磁粉及粘结磁体、双相纳米复合磁粉及粘结磁体的国内外现状、前景以及粘结NdFeB磁体的应用。     

模压成形各向异性NdFeB粘结磁体性能研究

采用模压成形方法制备各向异性粘结NdFeB磁体,主要研究了粉末粒度以及取向磁场强度对粘结磁体磁性能和力学性能的影响.试验结果表明,随着磁粉粒度的减小,粘结磁体的剩磁有所增加,但矫顽力下降明显.随着取向磁场强度的增大,粘结磁体剩磁进一步提高,各向异性明显;粘结磁体密度及抗压强度随磁粉粒度的减小略有提高.经粒度配比后制备的粘结磁体获得了较高的磁性能和抗压强度,其B_r、H_(ci)及σ_(bc)分别为0.81T、828kA/m及204MPa.     

北科大近终形粘结磁体研究项目顺利通过验收

3月 2 6日 ,北京市科技计划项目“近终形粘结磁体的研究及各向异性NdFeB磁粉中试”顺利通过验收 ,该项目由北京科技大学曲选辉教授领导的课题组承担的。其中 ,各向异性NdFeB磁粉、磁体的性能指标全部超出合同要求 ,自主开发的径轴向两用磁场注射成形机达国际先进水平 ,并获北京市科学技术二等奖。该项目的目标是建立一条年产 30t的各向异性NdFeB磁粉中试生产线 ,解决粘结磁体精密成形关键技术及设备问题 ,推广近终形粘结磁体的应用领域北科大近终形粘结磁体研究项目顺利通过验收     

d-HDDR各向异性NdFeB磁粉及其磁体在电机上的应用

本文着重介绍通过严格控制氧化—歧化—脱氢—再结合(d-HDDR)化学反应过程中的氢气压而得到的各向异性NdFeB磁粉。用此磁粉制备的压制成形粘结磁体最大磁能积高达199 kJ/m3(25MGOe),可稳定地用于150℃温度下。而注塑成形的粘结磁体最大磁能积为119 kJ/m3(15MGOe),显然,此类各向异性粘结磁体是供制备高性能电机的理想材料。     

粘结剂含量对粘结NdFeB磁体磁性能和抗压强度的影响

用环氧树脂粘结剂制备了NdFeB粘结磁体,探讨了粘结剂含量对粘结磁体磁性能和抗压强度的影响规律及机理.当粘结剂含量为1%(质量分数,下同)时,磁粉不能完全被包覆、粘结,磁体密度、磁性能和抗压强度低;当粘结剂含量为5%时,粘结剂体积分数大,稀释了磁体的磁性能,多余的粘结剂也使磁体抗压强度降低.粘结剂含量为2.5%时磁体具有较佳的性能:剩磁Br=0.616T;内禀矫顽力Hcj=784kA/m;最大磁能积(BH)m=58kJ/m3;抗压强度为236MPa.     

快淬NdFeB磁粉的磁选分离

快淬NdFeB磁粉的制备过程中有许多因素影响磁粉性能的均匀性 ,致使出现部分低性能的磁粉 ,磁选可把低性能的磁粉分离出来。研究了磁选时辊轮转速、磁选次数以及磁场强度对快淬Nd9.5(FeCoZrAl) 84 .5B6 磁粉分离效果的影响。研究表明 ,选择合适的磁选工艺参数能有效分离低矫顽力的磁粉。与未磁选的Nd9.5(FeCoZrAl) 84 .5B6 磁粉制作的粘结磁体相比 ,磁选后的磁粉制作的粘结磁体磁性能有较大的提高 ,最佳磁性能为 :Br=697.4mT ,Hcb=44 2kA·m- 1 ,Hcj=741kA·m- 1 ,(BH) max=77kJ·m- 3。     

成形工艺对粘结NdFeB磁体结构和磁性能的影响

在粘结NdFeB磁体模压成形过程中存在较大的压力损失，引起磁体密度分布不均匀，致使磁体密度减小。本文研究了压制压强、预压成形和压制方式等对粘结NdFeB磁体结构和磁性能的影响及机理。研究表明：随着压制压强提高，粘结NdFeB磁体的密度和磁性能显著增大；粒度配合、预压成形和双向压制等办法均可增大粘结NdFeB磁体的密度和磁性能；在适当的压制压强下，将粒度配合、预压成形及双向压制工艺结合，制备出密度达到6．5g／cm^3、磁能积达到104kJ／m^3的粘结NdFeB磁体。     

HDDR NdFeB磁粉两步法伴温磁场取向制备高性能柔性各向异性NdFeB黏结磁体

利用高性能吸氢-歧化-脱氢-再复合(HDDR)NdFeB各向异性磁粉,通过两步法伴温磁场取向工艺制备高性能柔性各向异性NdFeB黏结磁体,重点研究了两步法伴温磁场取向工艺制备出不同成分配比磁体的磁性能和力学性能.结果发现:制备出磁体的取向度有大幅度提高,当成分配比(质量分数)为96.5%磁粉+1%偶联剂+2.5%黏结体系的磁体在120℃加热保温30 min磁场取向后,磁能积达到97 kJ·m-3,而磁体的矫顽力最大降幅只有1.3%,论证了两步法伴温磁场取向工艺制备柔性各向异性NdFeB黏结磁体在实际生产的可行性.环氧树脂润滑剂的加入使得制备出磁体的延伸率和柔性均大幅度下降,并且加入量越多,下降幅度越大,因此环氧树脂润滑剂最大加入量不应超过1%(质量分数).      

注射成形制备NdFeB粘结磁体

为了制备出高性价比的粘结NdFeB注射磁体，本文系统的研究了粘结剂、添加剂的含罱以及磁粉装载量对注射磁体的加工性能、磁性能等的影响规律，并从微观上揭示了其机理。本文采用低成本的陶广：快淬钕铁硼磁粉和国产尼龙6粘结剂制备出了磁性能Br为0．5158T、Heb为321kA／m、Hcj为730kA／m和（BH）max为40kl／m^3的注射磁体，其性能与日本Mate公司的RNI-50产品性能相当，而价格却低得多.     

Anisotropic NdFeB/SmCoCuFeZr composite bonded magnet prepared by warm compaction process

Anisotropic NdFeB/SmCoCuFeZr composite bonded magnets were prepared by warm compaction process. The effects of adding SmCoCuFeZr magnetic powder on the properties of anisotropic bonded NdFeB magnet were investigated in this work. The results show that, both magnetic properties and temperature stability of the bonded magnet can be improved by adding fine SmCoCuFeZr magnetic powder. In the present study, the optimal content of SmCoCuFeZr magnetic powder was about 20 wt.%, in this case, the Br, Hcj, and(BH)maxof the NdFeB/SmCoCuFeZr composite magnet achieved 0.943 T, 1250 kA/m, and168 kJ/m~3, respectively.     

粘结钕铁硼磁环在高性能永磁式步进电动机上的应用

钕铁硼粘结磁体是一种将钕铁硼磁粉与高分子树脂或塑料或低熔点合金及各种添加剂均匀混合,用模压、挤出或注射成形等方法制成的复合永磁材料。国内外对其机理的研究已比较深入,本课题仅就钕铁硼粘结磁体特别是应用于高性能永磁式步进电动机的粘结钕铁硼多极磁环的制备工艺中的关键问题进行了研究,内容包括：（１）专用粘结剂的选择;（２）磁粉选择;（３）薄壁磁环自动压制成形;（４）表面防锈处理方式的选择;（５）多极充磁;（６）磁环转子整体注射成形。结果表明：在解决了上述关键工艺问题后,粘结钕铁硼多极磁环已批量应用于高性能永磁式步进电动机,替代进口或使原有的电机升级换代     

Investigation on the Moldability of HDDR NdFeB Bonded Magnet Prepared by Compression Molding Method

The phenomenon of uneven density distribution is inevitable in the process of preparing bonded magnets with complicated shape or with large geometric size by compression molding due to the friction among magnetic powder grains and between magnetic powder and the die wall, which reduces the pressure along the compression direction. In order to improve the density distribution homogeneity, the thin-wall rings with composition of HDDR NdFeB prepared by compression molding were selected as the investigated object in this study. It was systematically investigated on the effect of addition level of lubricants and the addition methods of lubricants and strengthener on magnet density, density distribution and on magnet strength. By means of joint addition of lubricants and strengthener, which increases the magnet density and improves the magnet density distribution under the precondition of keeping the magnet strength unreduced. Thus the moldability of the bonded magnets is improved.     

2种NdFeB粉末的混炼研究

采用快淬法和雾化法制得的2种不同形貌的NdFeB磁粉,以尼龙12作粘结剂,研究了注射成形粘结磁体的混炼过程。分析了2种磁粉的形貌与粉末粒度及其分布,对混合料的粉末临界充填率、均匀度、流变特性的影响,以及混炼温度对磁性能的影响。     

Manufacturing of Injection-Molded NdFeB Magnet with (BH)max111 kJ · m-3

The bonded NdFeB magnets prepared by injection molding meet with the development tendency of the magnet in small volume, light weight and high performance ,and have a good prospect.In this paper, a modified nylonbased binder was developed for powder injection molding of NdFeB bonded magnets.The effects of pretreatment of NdFeB anisotropic magnetic powder produced with HDDR processing on the anti-oxidation behaviors of powder and the final magnetic properties of the molded bonded magnets were studied.The optimal powder loading of 65 vol% was achieved with the modified binder.It was found that the properties of the bonded magnets were mainly affected by the powder surface pretreatment and the intensity of the applied alignment magnetic field during injection molding for a certain powder.Bonded magnets with remanence of 0.820 T, intrinsic coercivity of 1140.3 kA· m-1 and maximum energy product of 111 kJ · m-3 were produced with the optimal processing.     

Nd-Fe-B永磁材料的粉末注射成形技术

介绍了目前采用的几种粉末注射成形用Nd-Fe-B磁粉的制备方法及特点;讨论了粘结剂、改性剂及磁场取向对注射成形Nd-Fe-B粘结剂磁体和烧结磁体最终磁性能的影响;指出了注射成形Nd-Fe-B磁体的现在以及潜在的应用市场。在此基础上,指出了今后开展研究工作的方向。     

Study on Fabrication Process of Anisotropic Injection Bonded Nd-Fe-B Magnets

This study is on the injection molding process for the fabricating anisotropic Nd-Fe-B bonded magnets. The effects of powder loading, particle size of the magnetic powder, polymer binder and the fabricating process on the magnetic and the mechanical properties of anisotropic Nd-Fe-B magnets were investigated. The proper powder loading, particle size and binder are 60%(vol%), 75–106 μm and PA 1010, respectively. The optimum condition for good magnetic properties of anisotropic injection bonded Nd-Fe-B magnets is mixing the binder and the chemicals in the temperature between 205–215 °C, injection temperature of 265 °C, the injection pressure of 5–6 MPa, the press time of 5 second, and molding temperature of 80 °C. The magnetic properties of anisotropic bonded Nd-Fe-B magnets made in above conditions from d-HDDR powder were: B_r=0.72 T, _iH_c=983 kA/m, (BH)_max=75 kJ/m^c.     

Effect of Particle Size and Distribution of Rapidly Quenching NdFeBMagnetic Powder on Magnetic Properties of PolymerBonded NdFeBPermanent Magnet

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纳米晶Fe_3B/Nd_2Fe_(14)B粘结永磁体的磁性能研究

本文研究了粘结剂含量和温度－时间变化对纳米晶Ｆｅ３Ｂ／Ｎｄ２Ｆｅ１４Ｂ粘结永磁材料的磁性能影响。结果表明降低粘结剂含量可显著地提高纳米晶Ｆｅ３Ｂ／Ｎｄ２Ｆｅ１４Ｂ粘结永磁的磁性能；环境温度对纳米晶Ｆｅ３Ｂ／Ｎｄ２Ｆｅ１４Ｂ粘结永磁的磁性能具有重要影响，在较高的温度下其磁性能将显著下降，因此纳米晶Ｆｅ３Ｂ／Ｎｄ２Ｆｅ１４Ｂ粘结永磁只能在较低的温度环境下使用     

YZT13B磁胶条综合性能的改善

试验分析了成份不同的配比、不同的粘结剂类型和工艺对磁胶条磁性能和物理性能的影响，结果表明：质量分数90％磁粉、8％CPE、2％添加剂配比的YZT13B磁胶条综合性能满足使用要求；而8％CPE中采用70％135A型和CPE与30％B型CPE对物理性能提高效果显著而磁性能满足要求；40％-50％压下量可以获得较佳综合性能。