共查询到18条相似文献,搜索用时 187 毫秒
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研究磁粉粒度对注射成形粘结NdFeB磁体性能的影响。结果表明:随着磁粉粒度减小,喂料粘度值升高,粘流指数n值降低,其注射工艺性能更好;制备粘结磁体的抗压强度更高,但其不可逆磁损失也增大。NdFeB磁粉粒度太粗或太细均不利于磁体性能的提高,其最佳粒径范围是80-100μm;通过粒度级配可以降低喂料粘度值或提高临界装载量,在此基础上制备高性能的各向异性粘结NdFeB磁体,其Br、iHc、(BH)max及σbb分别为878 mT、1 212.3 kA/m、128 kJ/m^3及73 MPa。 相似文献
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对NdFeB磁粉进行了不同表面处理,研究了表面处理对磁粉抗氧化性、喂料流动性及粘结磁体性能的影响规律.结果表明:(1)NdFeB磁粉经改性处理后,粉末在300℃及500℃的氧化增重率大大降低;而且采用先磷酸后硅烷的复合处理工艺要比单一的硅烷处理或单一的磷酸处理效果更好;(2)KH550硅烷耦联剂能有效地改善NdFeB磁粉与尼龙粘结剂相容性,相应制得的喂料流动性要好于未改性磁粉,而且能相对提高NdFeB磁粉的装载量,使得最大装载量(体积分数)达到67%;(3)通过对磁粉表面改性,改善了磁粉与塑料粘结剂的界面特性,不仅提高了注射成形粘结磁体的磁学及力学性能,而且改善了粘结磁体的耐热性能. 相似文献
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粘结剂作为粘结NdFeB磁体制备过程中的重要组成部分,其作用是提高磁粉颗粒的流动性和粘结强度,保证产品的力学性能和磁性能的稳定。采用理论与实验相结合的方法,研究了粘结剂含量对粘结NdFeB磁体力学性能和磁性能的影响。在此基础上,制备了高性能粘结NdFeB磁体。利用扫描电子显微镜(SEM)对磁体的结构和形貌进行了表征。在NIM-200C磁滞回线仪和电子万能试验机(AG-X plus)上分别测定了环形粘结NdFeB磁体(RSM)的磁性能和力学性能。结果表明,当粘结剂含量为3%(质量分数)时,粘结NdFeB磁体密度最高(5.59 g/cm3),抗压强度最高(159 MPa),磁性能最佳。 相似文献
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注射成形法制取各向异性粘结NdFeB磁体的研究 总被引:6,自引:0,他引:6
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。 相似文献
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通过磁粉表面处理及在NdFeB磁粉中添加不同比例的粘结剂,制备了金属基和塑料基两种粘结磁体,研究了不同基体磁体的稳定性和磁性能,从断口SEM照片及结合理论分析可得出结论磁粉的表面处理可以改善磁体的稳定性及磁性能,通过磁性能测试及对比和退磁率的测量可以看出塑料基磁体的磁性能低于金属基磁体,但其稳定性却显著提高,塑料基磁体的使用温度可达150~180 ℃. 相似文献
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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) 总被引:1,自引:0,他引:1
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. 相似文献
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Siwu Tao Xin Lu Jianjun Tian Xuanhui Qu Y. Honkura H. Mitarai K. Noguchi 《稀有金属(英文版)》2009,28(3):245-247
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. 相似文献
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V. Panchanathan 《Journal of Materials Engineering and Performance》1995,4(4):423-429
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. 相似文献
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Bonded NdFeB magnets were prepared by compression molding. The effect of preparation technology on their magnetic and mechanical properties was studied through the analysis of density, Br Hcj, (BH)max, bending strength, and compressive strength of the bonded magnets. The results showed that the magnetic properties decreased with increasing binder content, whereas the mechanical properties increased. Brand (BH)max increased with rising pressure, whereas Hcj decreased. For a fixed mass fraction of the binder, the optimal pressure was 620 MPa and the best thermosetting temperature was 160℃. These conditions made the bonded magnets have the optimal mechanical properties. Scanning electron microscopy (SEM) analyses of the fracture surfaces indicated that the epoxy resin bonded magnets exhibited brittle behavior. 相似文献
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Bonded Terfenol-D composites,with high electrical resistivity and low eddy current loss,can be used in an alternating magnetic field with high frequency.However,the nonmagnetic binder impairs the magnetostriction of the composites.To achieve high magnetostriction and low eddy current loss,the mixture of the alloy powder and binder was compressed at low pressure in an oriented magnetic field.After this,the aligned samples were recompressed by cold isostatic pressing(CIP).Besides,the effect of particle size on the magnetostriction of the bonded Terfenol-D composites was also studied.The results showed that the bonded Terfenol-D composites had excellent magnetostriction when the particle size was 50-80 μm.The oriented magnetic field and CIP could improve the magnetostriction of the bonded composites,which reaches 1020×10-6.The bonded Terfenol-D composites had good compact structure and high density(7.24 g/cm3).The magnetic loss of the bonded Terfenol-D composites was 192 mW/cm3 at a frequency of 100 kHz in a magnetic field of 960 A/m,which was about one third of that of casting Terfenol-D alloys. 相似文献
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Fuqiang ZhaiAizhi Sun Duo YuanJin Wang Shen WuAlex A. Volinsky Zhixin Wang 《Journal of Alloys and Compounds》2011,509(3):687-690
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, Hirr 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. 相似文献
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The microstructure and characteristics of pre-sintered strontium ferrite powderwere investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The present study shows that the pre-sintered strontium ferrite powder is provided with a certain particle size distribution, which results in high-density magnets. The strontium ferrite particle has a laminar hexagonal structure with a size similar to ferrite single domain. Ferric oxidephase due to an incomplete solid phase reaction in the first sintering is discovered, which will deteriorate the magnetic properties of ferrite magnet. In addition, the waste ferrite magnets with needle shape arranging along C axis in good order into the powders are found, which have no negative effects on finished product quality. 相似文献