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2∶17型SmCo永磁体自1977年问世以来,已有很大发展,其性能不断提高.因其具有优异的磁性能,在微波通讯技术、航空航天、国防工业、交通运输业等很多领域有着广泛的应用.最近又提出了最高工作温度大于400 ℃的永磁材料的要求,因2∶17型SmCo永磁体具有高的居里温度和较高的磁能积而成为首选材料.从1996年至今出现了2∶17型SmCo高温磁体的研究热潮,本文主要介绍了2∶17型SmCo永磁的发展过程、磁体的磁性能、制备工艺、应用情况及其发展趋势. 相似文献
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采用XRD,AFM等检测方法研究了Fe含量对Sm(CobalFexCu0.049Zr0.024)7.5(x=0.102-0.282)的磁性能和显微结构的影响。结果表明,磁体的Br先随Fe含量的增加而增加,在x=0.239时达最大值1.099 T,进一步增加Fe含量由于FeCo软磁性相的形成而导致Br下降。当Fe含量由x=0.239增加至0.282时,Hci由最大值1660.3 kA·m^-1迅速降低至979.1kA·m^-1。Fe含量对磁体的相结构没有显著的影响,主要由2∶17R相、1∶5相和2∶17H相构成。但当Fe含量x〈0.197时,Sm(CobalFexCu0.049Zr0.024)7.5的胞状组织未发生显著变化,平均尺寸约为80nm;当Fe含量x〉0.197时,胞状结构发生长大,均匀性变差,胞状结构的变化导致矫顽力的温度稳定性随Fe含量的增高而大幅降低;当x=0.282时,磁体在500℃下的Hci只有114 kA·m^-1,磁通不可逆损失达-36.7%。 相似文献
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用粉末冶金法制备了Ni-Cr-Mo-Al-Ti-B-MoS2系宽温度范围自澜残杀则试了合金机械性能及其在室温600℃范围内的摩擦磨损性能,同时还了其耐磨机理。研究结果表明,MoS2质量分数为10%的合金具有较好的机械和摩擦磨损综合性能。该合金主要由Ni基固溶体、Ni3Al、Ni3(Al,Ti)、不定比化合物CrxSy、MoS2和Mo2S3等相组成,在室温至300℃范围内摩擦表面形成含硫化合物复合膜 相似文献
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MgCNi3, an intermetallic compound superconductor with a cubic perovskite crystal structure, has been synthesized using fine Mg and Ni powders and carbon nanotubes (CNTs) as starting materials by the conventional powder metallurgy method. The composition, microstructure and superconductivity are characterized using x-ray diffraction (XRD), energy dispersive x-ray (EDX) analysis, scanning electron microscopy (SEM), and superconducting quantum interference device (SQUID) magnetometer. The results indicate that the phases of the synthesized samples are MgCNi3 (major phase) and traces of C and MgO. The MgCNi3 particle sizes range from several hundreds of nanometres to several micrometres. The onset superconducting transition temperature Tc of the MgCNi3 sample is about 7.2 K. The critical current density Jc is about 3.44 × 10^4 A/cm^2 calculated according to the Bean model from the magnetization hysteresis loop of the slab MgCNi3 sample at 5 K and zero applied field. 相似文献
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We study the propagation and collision of the compacton-like kinks in the system of an anharmonic lattice with a double well on-site potential by a direct algebraic method and numerical experiments. It is found that the localization of the compacton-like kinks is related to the nonlinear coupling parameter Cnl and the potential barrier height V0 of the double well potential. The velocity of the propagation of the compacton-like kinks is determined by the linear coupling parameter Cl, the nonlinear coupling parameter Cnl and the localization parameter q. Numerical experiments demonstrate that appropriate Cl is not detrimental to a stable propagation of the compacton-like kinks. However, the collision of compacton-like kinks and anti-kinks in the lattice with comparatively small Cl leads to the emergence of a discrete stationary breather and small amplitude nonlinear oscillation background, while moderate Cl results in the emergence of two deformed kinks with radiating oscillations and lower propagation velocities. 相似文献
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采用M-2000型摩擦磨损试验机研究了干摩擦条件下纤维取向对C/C复合材料与40Cr钢摩擦副摩擦磨损特性的影响.结果表明:随着载荷增加,纤维轴向与滑动方向一致(X方向)时的摩擦系数较垂直滑动方向/摩擦表面(Y/Z方向)时的变化幅度低,X方向试样基体炭的磨屑损耗快,磨损较大;Y/Z方向试样基体炭的磨屑移动能力低,易堆积成膜,但在高载荷下纤维易被剪切.对于全光滑层热解炭材料,随着载荷增加,其X方向的磨损体积损失在0.4266~0.997mm^3之间,Y方向的磨损体积损失在0.448~1.020mm^3之间,而Z方向的磨损体积损失在0.349~1.420mm^3之间;对于全树脂炭材料,X方向的磨损体积损失随载荷增加在0.429~1.134mm^3之M波动,而Y方向的磨损体积损失在0.237~0.981mm^3之间变化. 相似文献
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Ni-Cr-Mo-Al-Ti-B-MoS2系合金高温摩擦学特性的研究 总被引:2,自引:0,他引:2
用粉末冶金法制备了Ni-Cr-Mo-Al-Ti-B-MoS2系宽温度范围自润滑合金材料,测试了合金机械性能及其在室温至600 ℃范围内的摩擦磨损性能,同时还探讨了其耐磨机理.研究结果表明,MoS2 质量分数为10% 的合金具有较好的机械和摩擦磨损综合性能.该合金主要由Ni基固溶体、Ni3Al、Ni3(Al,Ti)、不定比化合物CrxSy、MoS2 和Mo2S3 等相组成,在室温至300 ℃范围内摩擦表面形成含硫化合物复合膜而起润滑作用,高温摩擦时承载表面形成釉质层,次表层形成氧化层,其硬度比合金基体高,这是合金具有良好高温耐磨性的基础.高温下摩擦表面及磨屑中的氧化物及残余硫化物的协同作用使摩擦系数进一步降低. 相似文献
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This paper studies the evolution of wave in the system of a pure
anharmonic lattice with a double well on-site potential by numerical
calculation. It finds that an initial distribution of static or
moving wave can evolve into two travelling soliton-like trains with
contrary directions and a region of oscillation in this lattice
system. It presents that some cases with cosine-square-shape and
Gaussian-shape initial distribution of static or moving wave will
produce ordered soliton-like train. Careful numerical observation
shows that the centre oscillation region in this system may act as a
resource of generating soliton-like train. 相似文献
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研究了Sm(CobalFe0.1Cu0.16Zr0.04)7.0快淬带在微波场作用下晶化处理后的微结构及磁性能。结果表明,Sm(CobalFe0.1Cu0.16Zr0.04)7.0在传统晶化处理后晶粒尺寸约为500-1500 nm,FeCo软磁性相异常长大。微波场作用下,合金在700℃处理4 min时晶粒尺寸约为10 nm,磁体的Ms为1.192 T,Hci为14.8 kA.m-1;在650-700℃处理4-30 min均获得了晶粒尺寸为20 nm的单一球形颗粒,磁体主要由1∶7主相和少量Sm2Co7相构成。在650℃晶化处理30 min后,合金具有方形度较好的平滑磁滞回线,Hci为542.6 kA.m-1,剩磁比达0.86。微波场可细化晶粒尺寸并抑制FeCo软磁性相的生成,使磁体具有良好的交换耦合作用。 相似文献
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