金属复合添加提高烧结NdFeB永磁材料韧性的尝试

烧结钕铁硼永磁材料属粉末冶金制品,韧性较差.本研究在烧结钕铁硼永磁材料生产过程中复合添加纤维状金属丝以改善磁体韧性.结果表明,适量添加纤维状金属丝,在不明显影响磁体性能的前提下,材料断裂韧性提高约20～30%,为提高烧结钕铁硼永磁材料的韧性提供了有益的尝试.     

高性能NdFeB永磁材料

介绍了NF40H牌号NdFeB永磁材料的研制过程。通过组合调配添加成分和采取一定的防氧化措施，用粉末冶金法生产出Br=1.298T,HcB=963kA/m,HcJ=1408kA/m,(BH)max=318kJ/m^3的高性能NdFeB永磁材料；对生产过程中材料的氧化机理作了初步探讨；通过背散射成象图对NdFeB永磁材料的微观结构进行了分析；找到了一种适用的防氧化剂。     

中国NdFeB磁体的发展前景

分析了中国NdFeB永磁材料的现状,给出应用实例并展望了材料的发展前景。     

钕铁硼稀土磁体产业发展及市场前景

作为稀土最重要的应用领域之一,钕铁硼稀土永磁材料是支撑现代社会的重要基础材料,与人们的生活息息相关。小到手表、照相机、录音机、CD机、VCD机、计算机硬盘、光盘驱动器,大到汽车、发电机、医疗仪器等,永磁材料无所不在。2000~2010年,烧结钕铁硼磁体毛坯产量,全球年均增长率为20%,我国年均增长率为28%;粘结钕铁硼磁体产量,全球年均增长率为7%,我国年均增长率为21%。在低碳生活中充满了磁性材料,稀土永磁钕铁硼材料扮演着非常重要的角色。比如在风力发电、混合动力/电动汽车、节能家电等方面,都离不开稀土永磁材料。有赖于丰富的稀土资源,充足的技术人才、较低的人工成本和广阔的市场,我国稀土永磁产业的前途无限光明。中国不仅是全球最大的稀土永磁钕铁硼生产基地,也将成为钕铁硼应用的广阔市场。     

稀土粘结磁体与永磁电机

1 粘结磁体的特点永磁电机的长足发展与新型永磁材料的不断出现有密切的关系。在烧结的稀土永磁材料快速发展的同时,另一种稀土粘结磁体又后来居上,异军突起。这种直接将合金铸锭热处理后粉碎制得的磁粉(约占材料总重量的90％),添加粘结树脂混合后,再经压缩成型或注射成型等工艺而制成的稀士粘结磁体,能最大限度地改变磁体的形状自由度,从而获得烧结磁体难以得到的一些超薄型工件和形状复杂的磁体。其特点是     

汽车电机中永磁材料的应用及其发展前景

文章介绍了各种汽车电机对永磁材料的要求及应用。又从国内外汽车行业发展趋势的角度，提出汽车电机及永磁材料的需求前景。     

Sm2F317Ny型稀土永磁材料的最近进展（一）

综述了Ｓｍ２Ｆｅ１７Ｎｙ型稀土永磁材料的传统工艺的各种工艺因素对磁性的影响，还介绍了用其它方法制备Ｓｍ２Ｆｅ１７Ｎｙ型稀土永磁材料的现状。     

磁极组合型轴向磁场无铁心永磁电机的设计与分析

在现有Halbach阵列永磁电机的基础上,提出了一种磁极组合式的Halbach永磁阵列轴向磁场无铁心电机,阐述了该电机的结构与优点,分析了该电机的电磁转矩。借助三维有限元分析方法,优化设计了组成转子磁极的Halbach永磁材料、软磁材料尺寸。在综合考虑单位体积永磁体所产生电磁转矩和气隙磁密正弦性的基础上,确定了电机转子磁极上轴向磁化、切向磁化永磁体以及软磁材料的极弧系数。与传统Halbach结构轴向磁场无铁心永磁电机相比,优化后的磁极组合型轴向磁场无铁心永磁电机,在保证气隙磁密大小一定的基础上,减少了永磁体用量,降低电机造价,从而提高了电机性价比。样机实验和有限元分析结果验证了所设计电机的正确性和有效性。     

Nd—Fe—B磁体研制生产现状及发展趋势

一、前言60年代末,铁氧体永磁和铝镍钴永磁的需求量各占一半。70年代问世的第一、第二代稀土永磁,磁能积已达20～30MGOe,84年的产值超过了铝镍钴,因含昂贵的钴元素,应用受到一定的限制。多     

粘结稀土永磁的发展动向

粘结稀土永磁材料近年来一直在以上的趋势发展，其中钕铁硼粘结磁体地发展最为迅速，预计１９９７年全球粘结钕铁硼磁体用的磁粉需求量将达到２０００吨。本文简要介绍粘结稀土永磁的种类、用途及温度稳定性的情况，并展望了中国的粘结钕铁硼磁体的发展前景。     

金属注射成形技术及其在磁性材料中的应用

概述了金属注射成形（ ＭＩＭ）技术的基本过程及其特点,从几种 ＭＩＭ典型工艺分析入手介绍了ＭＩＭ技术的发展状况,最后介绍了该技术在磁性材料中的应用。     

Cost-Effective Optoelectronic Packages Using Powder Metallurgy

In this paper, we propose powder metallurgy for optoelectronic packages in order to reduce the cost of laser packages. Conventional die compaction (DC) and metal injection molding (MIM) are used for the shaping of powder metallurgy. The distinguishing types of inherent porosity in DC and MIM steels have their respective effects on the defect mechanisms of laser welding joints. For DC steel with 85% relative density and continuous porosity, the rising gas pressure pushes the molten metal out of the welding regions, resulting in weak and unstable welding joints. For MIM steel with more than 95% relative density, the laser power dominates the defect mechanisms, and the defect-free welding joints with optical spot size of$400 mu$m can be attained by using laser power of less than 1.0 kW. Although elimination of inherent porosity in MIM steel under optimum welding condition can give rise to additional postwelding-shift (PWS), it is still controlled to less than$2 mu$m, resulting in optical coupling loss of less than 15%. The advantage of applicability of the MIM method to several materials makes it possible to employ SS316L, Kovar, and Invar, which have the characteristic of better property for laser welding but difficult machining, as the metal housing in low-cost lightwave communication system. Thus, using MIM Invar with low coefficient of thermal expansion can minimize the tracking error, which is an important issue for bidirectional and triple-directional optoelectronic packages. The reliability data demonstrate that the laser modules using MIM steel as construction housing are stable and reliable.     

"粘结磁体2000"一瞥:粘结钕铁硼

介绍了“Ｐｏｌｙｍｅｒ Ｂｏｎｄｅｄ Ｍａｇｎｅｔｓ２０００”国际会议关于粘结钕铁硼的关情况，介绍了粘结钕铁硼技术发展状况及市场方面的信息等。     

Simulation Analysis of Microgrid Voltage Stability with Multi-induction Motor Loads

This paper studies the voltage stability problem in microgrid with multi-induction motor (MIM) loads. Firstly, the dynamic coupling relationship between grid voltage and each motor load slip in microgrid with MIM loads is deduced based on the power balance theory of power system. Then, a multi-source and master slave control based microgrid model is built, where Matlab/Simulink software is used to analyze microgrid voltage stability under circumstances of MIMs superimposed starting and microgrid fault. Through simulation calculation and analysis, the measures to improve the voltage stability of microgrid with MIM loads are proposed. According to the simulation results, the interaction between MIM loads has great influence on microgrid voltage stability. In addition, the critical cleaning time (CCT) of series connected master slave control based microgrid is affected by the distance between three phase short circuit fault location and the induction motor load location, as well as the distance between fault location and main control unit. The microgrid voltage stability can be effectively improved by applying methods of superimposed starting strategy and fast motor cutting strategy. The conclusion provides a reference for voltage stability research and control of the microgrid with MIM loads.     

金属注射成形烧结软磁合金的研究状况

介绍了国内外采用金属注射成形技术制备的几种烧结软磁合金材料,包括纯铁、软磁不锈钢、铁硅合金、铁钴合金和铁镍合金,并与精密锻造和传统粉末冶金方法进行了对比,分析了采用注射成形技术生产软磁合金材料的优势.     

Design of plasmonic half-adder and half-subtractor circuits employing nonlinear effect in Mach–Zehnder interferometer

Plasmonic metal–insulator–metal (MIM) waveguides have the unique attribute of propagating surface plasmons beyond the diffraction limit. In this paper, basic designs for half-adder and half-subtractor circuits are proposed based on the nonlinear effect in Mach–Zehnder interferometers designed using plasmonic MIM waveguides. The proposed devices are studied in the third optical communications window with transverse magnetic polarization. The designs are verified by the finite-difference time-domain technique with the help of MATLAB simulations.     

High-speed imaging of the pulsed-field flashover of an aluminaceramic in vacuum

An intensified high-speed imaging technique was used to observe the optical events associated with the pulsed-field breakdown of an alumina ceramic tube having two concentric planar electrodes metalized onto its end face. HV pulses, typically of 5 kV amplitude (5 kV μs ^-1 rate of rise), were applied to the radial MIM insulator-electrode regime under ultrahigh vacuum (pressure <5×10^-7 Pa), with video recordings made at 1000 frames per second. Images of the observed breakdown phenomena are presented, viewed both along the center axis and also in the plane of the MIM structure. These breakdown images are discussed in relation to plasma jets associated with vacuum arcs and, in particular, on the nature of the ion species within such jets     

Sm2Co17稀土永磁材料的研究概况

随着现代工业的发展,对永磁体的要求也越来越高,既要求磁性能优良,又要求稳定性好,可靠性高.目前,对Sm2Co17稀土永磁材料的研究主要体现在高温永磁体、高稳定性永磁体和成型工艺等方面.影响Sm2Co17磁体性能的因素较多,其中比较重要的因素是磁体的显微组织、时效处理及合金的化学成分等.