射流电铸快速成形纳米晶铜的研究

采用射流电铸快速成形新技术研究了制备块体纳米晶铜的工艺，制备了具有一定形状的块体纳米晶铜样品，用X射线衍射法分析了纳米晶铜的微观组织结构，结果表明，电铸电流密度和电铸速度随电铸电压和喷射速度的增大而提高，该新技术方法可用于快速制备具有一定形状的块体纳米晶铜材料。     

粘结纳米复相磁性材料制备及性能的研究

采用磁粉晶化和粘结工艺制备纳米复相磁材的方法，研究了热处理工艺和粘结剂含量对纳米晶磁体磁性能的影响，结果表明热处理温度、热处理时间、粘结剂含量明显的影响纳米晶的形成及其磁性能。热处理为700℃、粘结剂含量在2％～3％（质量分数）时，纳米复合磁体可以获得较好的磁性能。该研究方法工艺简单，成本较低，具有一定的实用价值。     

晶化工艺对纳米复合永磁体组织和磁性能的影响

本文就晶化工艺对纳米双相复合永磁体的组织和磁性能的影响的研究进展做一综述,探讨了等温退火条件对纳米双相复合永磁体显微组织和磁性能的影响规律,发现传统的等温退火工艺对纳米复合永磁体的进一步发展具有较大的局限性,提出了几种新的制备纳米双相复合永磁体的晶化工艺.     

电刷镀镍基SiO2复合镀层热稳定性能研究

采用脉冲换向复合电沉积的方法，制备出了含纳米SiO2的纳米晶复合镀层。通过引入弥散纳米SiO2的技术途径，来阻碍纳米晶晶粒界面的迁移，进而控制纳米晶的高温生长。通过改变工艺参数，研究纳米SiO2对镀层纳米晶生长的影响规律，探讨纳米第二相对纳米晶复合镀层晶粒热稳定性控制的机制。     

电沉积法制备块体纳米晶材料的研究进展

综述了电沉积法制备块体纳米晶材料的原理;阐述了电流密度、电流波形、有机添加剂等工艺参数对沉积层晶粒尺寸的影响;介绍了直流电沉积、脉冲电沉积、喷射电沉积和复合电沉积等几种常见的电沉积方法;概述了电沉积法制备块体纳米晶材料的国内外研究现状;探讨了电沉积块体纳米晶材料的力学性能、磁学性能、耐蚀性能、热稳定性及其应用前景.     

高性能稀土永磁材料制备与研究的进展

稀土永磁材料的高磁性能使其成为应用广泛的基础性功能材料．概述了高性能烧结Nd-Fe-B和纳米复合Nd2Fe14B/α-Fe永磁材料的制备与性能研究的几点进展．在采用速凝铸带加氢爆工艺制备高性能烧结Nd-Fe-B磁体方面，概述了材料中添加元素对磁体显微组织和磁性能的影响，以及制备工艺对高能积磁体的力学性能和耐腐蚀性能的影响．在采用非晶晶化工艺制备纳米复合Nd2Fe14B/α-Fe型永磁材料方面，概述了添加元素在非晶晶化过程所起的作用，及其对材料相组成和微结构及磁性能的影响；同时概述了快淬速度、压力和晶化处理等制备工艺对材料微结构和磁性能的影响．     

滴加方式对NAC-FAS工艺制备ZnO-TiO_2复合纳米晶的影响

以硫酸氧钛、二水合乙酸锌、氢氧化钠为原料,研究了不同的滴加方式对NAC-FAS工艺制备ZnO-TiO_2复合纳米晶的影响,利用X射线衍射仪(XRD)、透射电子显微镜(TEM)对样品的结构、形貌进行了表征。结果表明:通过NAC-FAS工艺预制TiO_2纳米晶可以制备得到复合ZnO-TiO_2纳米晶,其平均粒径为15nm,复合纳米晶呈球状。通过NAC-FAS工艺直接滴加反应溶液,不能制备得到ZnO-TiO_2,只能制备得到单一晶相或非晶相。     

晶化法制备的纳米晶材料的研究现状

介绍了非晶合金晶化法制备纳米晶材料的各种工艺过程和特点，综述了该法的影响因素、机理等方面的现今研究成果，对该法的发展及应用前景作了展望。     

NdFeB纳米晶复合永磁材料的研究

自从NdFeB纳米晶复合永磁材料出现以来．由于其潜在的优异磁性能和巨大的商业价值,成为近几年来磁性材料领域研究的热点。本文重点论述添加合金元素和制备工艺对NdFeBN米晶永磁材料的微观结构和磁性能的影响,并概述近年来新的晶化工艺。     

铁基纳米晶软磁合金的研究

本文主要评述了铁基纳米晶软磁合金的晶化过程、组织结构及其与磁性能之间的关系,分析了优异磁性能的起源,并详细论述了解释其优异磁性能的各向异性模型,提出了目前在该模型上存在的问题.此外,还介绍了纳米晶软磁材料的制备方法,并在最后对纳米晶软磁材料的应用及发展趋势作了展望.     

Tunable,Flexible Composite Magnets for Marine Monitoring Applications

This paper presents flexible NdFeB‐PDMS composite magnets with tunable magnetic and mechanical properties optimized for applications in corrosive marine environments. The magnetic and mechanical properties are studied for different NdFeB powder concentrations and the performance of the magnetic composites for different exposure times to sea water investigated systematically. The remanence and saturation magnetizations could be tailored by the powder concentration, whereby up to 70 wt% concentration could be employed without compromising the integrity of the magnets. The elastic modulus of the composite magnets is about 10⁵ times lower than the one of a bulk permanent magnet. This ensures a high bending flexibility, which allows the magnets to be attached to curved surfaces as illustrated for a giant clam, crab, and turtle. At the same time, the weight of the composite magnets is reduced by a factor of about 10, which poses less burden to animals’ natural free movement. Without a protective layer, the composite magnets lose more than 50% of their magnetization after 51 days in seawater. However, the durability of the composite magnets has been improved considerably by using polymer coatings. Parylene C is the most effective for this, providing corrosion resistance, flexibility, and enhanced biocompatibility. Parylene C films of 2 and 4 μm thicknesses provided excellent protection of the magnetic composite in corrosive aqueous environments for 65 and 82 days, respectively. By combining the composite magnets with tunnel magnetoresistance sensors, a magnetic animal monitoring system is established that is used to track the behavior of giant clam, crab, and turtle.

     

NdFeB纳米晶双相复合永磁材料研究进展

NdFeB纳米晶双相复合永磁材料，由于其潜在的优异磁性能和商业价值，成为当今材料领域研究的热点。本文就近年来NdFeB纳米晶双相复合永磁材料的发展状况，从该类合金的交换耦合作用、分类以及提高磁性能的方法三个方面为重点，作简要的评述。     

高性能各向同性及各向异性Nd-Fe-B/Fe复合磁体的制备

采用将Nd-Fe-B磁粉与Fe粉混合的方法,并结合真空感应热压烧结技术制得高性能的各向同性及各向异性复合磁体。研究了Fe粉含量对热压磁体磁性能的影响,以及温度和压力对磁体致密度和磁性能的影响。结果表明,适量的Fe粉添加(3%,质量分数)可提高热压磁体磁性能;升高温度或提高压力均可大幅提高磁体致密度,但过高的烧结温度使晶粒快速长大,恶化磁体磁性能,而温度过低磁体难易全致密化。在最佳热压温度及压力下制备的热压磁体具有最佳的磁性能:Br=0.852T,Hcj=798kA/m,(BH)m=131.5kJ/m3,磁体密度达7.72g/cm3;热变形后,最大磁能积达331kJ/m3。     

Biaxial testing of high strength carbon fiber composite cylinders for pulsed magnet reinforcement

A methodology is introduced to test carbon-fiber-reinforced, hoop-wound composite cylinders for their biaxial mechanical properties under axial compression and hoop tension. The understanding of the behavior of these composites under biaxial loads is extremely important in the design of pulsed magnets. These composites are used as reinforcements for both the inner conducting layers and as an overall exterior reinforcement. Testing of actual pulsed magnets to ascertain design change effects of composite reinforcement schemes on the maximum attainable field can be expensive; hence, a standard biaxial testing method is desirable which is relevant to the design of pulsed magnets. In this investigation, an attempt was made to produce a standard testing procedure aimed at measuring the biaxial mechanical properties (elastic, plastic, and failure envelope) of composite materials. This methodology was applied to two different carbon/epoxy based composites. The results of these tests (elastic properties and failure points) are compared with theoretical predictions, specifically those due to Tsai-Wu.     

纳米复合永磁多层膜的研究现状

纳米复合永磁材料由于其潜在的优异磁性能和商业价值,成为当今磁性材料领域的研究热点.就近几年来纳米复合永磁多层膜的发展状况,简要介绍了其制备技术、交换耦合作用、反磁化以及各向异性的研究.     

Analytical Computation of the Full Load Magnetic Losses in the Soft Magnetic Composite Stator of High-Speed Slotless Permanent Magnet Machines

This paper presents an analytical model for predicting the stator full load magnetic losses in high-speed slotless permanent-magnet machines with surface-mounted magnets on the rotor and a stator core made of isotropic and conductive soft magnetic composite material (SMC). The losses are derived from the computation of the two-dimensional magnetic field distribution created by the rotor magnets, the currents in the stator windings and the eddy currents that circulate in the SMC stator core, according to the time and space harmonics. Both eddy currents and hysteresis losses are computed. The model is cross-validated by 2-D FE analysis in terms of magnetic field distribution and eddy currents losses. 3-D FE simulations are also carried out to quantify the end-effect on the stator no-load eddy current losses. The developed model is an efficient machine design tool, used here to quantify the variations of both the eddy currents and hysteresis losses under full load operation when the control angle is modified.      

Soviet research in cryogenic technology and applied superconductivity

This paper reviews the achievements of forty years of Soviet research in cryogenic technology and applied superconductivity, including air fractionation, helium liquefaction, refrigeration, superconducting magnet systems, composite conductors, dipole magnets, saddle winding magnets, electrical insulation properties, power transmission, and liquid helium storage and transmission.     

Sm2Co17二元复合粘结永磁材料的研究

系统研究了Sm2Co17磁粉含量对NdFeB、AlNiCo、Ferrite粘结复合磁体磁性能的影响,并通过多项式拟合的方法分析了实验结果.结果表明:Sm2Co17和其它三种永磁材料粘结复合时,磁粉之间的相互作用对矫顽力的影响较强.添加Sm2Co17来获得高矫顽力的粘结复合永磁材料从经济上来说是不可行的.     

Nd-Fe-B永磁合金的微结构和晶粒相互作用

本文介绍了Ｎｄ２Ｆｅ１４Ｂ相的晶格结构及内禀磁性，概述了Ｎｄ－Ｆｅ－Ｂ永磁体的微结构和晶粒相互作用。磁体微结构包括晶粒尺寸、取向和结构缺陷。晶粒相互作用可区分为长程静磁相互作用及近邻晶粒的交换耦合相互作用。我们分析了微结构和相互作用的关系及其对磁体性能的影响，最后介绍了具有发展前景的纳米交换耦合双相复合永磁材料。     

Hysteretic effects in pulsed superconducting magnets

Superconducting magnets operating in a pulsed field mode are exposed to magneto-mechanical, thermomechanical and purely mechanical stresses. Since most materials incorporated in the magnet, such as the composite conductor, the insulation, the impregnants and the reinforcements, are strained to the limit of their yield strength, the mechanical and electrical behaviour of these materials will change during the first period of operation, until equilibrium conditions are reached.In this paper a new model for J_c(B) is presented. Based on this model hysteretic losses are calculated and compared to measured data. Losses due to stress-induced pseudo-elastic effects of the composite are calculated.