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基于粘结NdFeB永磁体制备工艺优化实验,建立了一个最小二乘支持向量机(LS- SVM)算法模型用于工艺参数的优化.以粘结剂含量、固化温度、固化时间以及单位压制力大小四个工艺参数为影响因数,以剩余磁感应强度Br、矫顽力Hcj;和最大磁能积(BH)m为影响对象,通过最小二乘支持向量机算法模型建立起影响因素与影响对象之间的复杂的非线形关系.针对多影响对象,提出了一种γ和σ选择算法;以均匀设计试验结果为样本进行训练,用训练好的模型进行预测.结果表明,LS - SVM模型的实验结果与预测结果吻合良好,二者相对误差很小,对比ANN模型预测结果,LS - SVM模型具有更高的精度和运算速度,具有很好的实用性. 相似文献
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《中国稀土学报(英文版)》2017,(12)
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. 相似文献
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Itiswellknownthattheintergranularmi crostructureofsinteredNd Fe Bmagnetsplaysakeyroleindeterminingtheircoercivityandthermalstability[1,2 ] .Therefore ,itisimpor tanttofurthermodifyingtheintergranularmi crostructureviaalloyingorotherprocessingmethodinimprovi… 相似文献
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采用支持向量机算法,在实验数据的基础上,建立航空发动机阻燃钛合金的合金化元素与力学性能关系模型,分析合金化元素对力学性能的影响规律。模型的输入参数为V、Al、Si和C元素,输出参数为室温拉伸性能(抗拉强度、屈服强度、延伸率和断面收缩率)。结果表明:各个力学性能支持向量机模型的线性相关系数均在0.975以上,具有较高的预测能力;各个力学性能测试样本实验值与模型预测值的绝对百分误差均在5%以内,具有良好的泛化能力,能够有效地反映出阻燃钛合金的合金化元素与力学性能之间的定量关系,进而实现对该合金的成分优化。对于Ti?35V?15Cr阻燃钛合金,可以通过加入质量分数为0~0.1%的Si元素和质量分数为0.05%~0.125%的C元素,并减少质量分数为2%~5%的V元素,来提高力学性能;对于Ti?25V?15Cr阻燃钛合金,可以通过加入质量分数为1.5%~1.8%的Al元素和质量分数为0.15%~0.2%的C元素,来提高力学性能。 相似文献
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采用双合金法制备Nd24.38Ce0.52Gd6.65Febal.TM1.76B0.95(质量分数,%)永磁体,通过扫描电镜及能谱、AMT-4磁测试仪、电子万能力学试验机等手段研究烧结温度对磁体组织和性能的影响.结果表明:随烧结温度从1060℃升高到1100℃,在烧结温度为1080℃时,晶粒均匀且结合致密,富稀土相分布均匀,能获得较好的组织形态;富稀土相中稀土总含量从84.98%增加到98.04%,烧结过程中铈从主相显著扩散到富稀土相;磁体剩磁Br、矫顽力Hcj、磁能积(BH)max 先升后降,在1080℃烧结时获得较好的磁性能,分别为1.22 T、964 kA/m 和293 kJ/m3,同时磁体抗弯强度也达到最大值为257 MPa. 相似文献
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《钢铁研究学报(英文版)》2006
Nd-Fe-B/α-Fe nanocomposite magnets with high magnetic properties were successfully fabricated through a sonochemical process with carbonyl iron as Fe precursor and subsequently SPS. Experimental results show that α-Fe can increase the remanence of Nd-Fe-B/α-Fe nanocomposite magnets while decrease the coercivity. The demagnetizing curve indicates that the hard and the soft phases did not coupled very well, even though the remanence was improved. The magnetic properties of Br 8.61 kGs, Hcj 8.59 kOe and (BH)max 12.05 MGOe were obtained for Nd-Fe-B/α-Fe nanocomposite magnets with the nominal Fe content of 5 wt.%. It is noted, the exchange coupling was obviously enhanced by a MA process before SPS, and the magnets properties were increased to Br 9.42 kGs and (BH)max 14.27 MGOe for Nd-Fe-B/α-Fe nanocomposite magnets with the same Fe content. 相似文献
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烧结NdFeB磁体强度和韧性研究现状 总被引:2,自引:0,他引:2
烧结NdFeB永磁材料具有磁性能高、价格低、生产工艺简单等突出优点,因而自其开发以来,生产和应用取得了快速发展,并且其市场还将不断扩大。但是,这种材料强度和韧性差,机械加工困难,应用过程中容易开裂。因此,改善烧结NdFeB永磁材料的力学性能已成为一个迫切的需要。综述了该种材料的断裂机制及在改善材料强度和韧性等方面所做的研究工作,认为通过添加合金元素,韧化晶界,细化主相晶粒,是一种有效的方法。研究表明,材料的断裂方式主要为沿晶断裂,晶界上的薄片富Nd相是引起沿晶断裂的主要原因,通过微量添加合金元素能有效改善磁体力学特性。 相似文献
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Melt-spun Nd8Fe78B6Co4 magnetic powders and their bonded magnets were prepared with the optimization of compositions and preparation techniques. The microstructure change of alloy NdFeB and the relation between microstructure and heat-treatment were studied. The heat-treatment temperature is 200~700 ℃. The as-cast structure of the alloy is typically amorphous. Different melt-spun speed and different heat treatment could result in different magnetic properties of NdFeB magnets. Magnetic properties of NdFeB increase with the addition of element Co. The magnetic properties of magnet alloy get the best when the melt-spun speed reaches 23~26 m·s-1, heat treatment temperature is 690 ℃ and time is 30 min. 相似文献
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Rare earth permanent magnetic materials are typical electrical conductor, and their magnetic properties will decrease because of the eddy current effect, so it is difficult to keep them stable for a long enough time under a high frequency AC field. In the present study, as far as rare earth permanent magnets are concerned, for the first time, rare earth permanent magnets with strong electrical insulation and high magnetic performance have been obtained through experiments, and their properties are as follows: (1) Sm2TM17: Br=062 T, jHc=8037 kA/m, (BH)m=5897 kJ/m3, ρ=7 Ω·m; (2) NdFeB: Br=0485 T, jHc=76633 kA/m, (BH)m=3796 kJ/m3, ρ=9 Ω·m. The magnetic properties of Sm2TM17 and NdFeB are obviously higher than those of ferrite permanent magnet, and the electric insulating characteristics of Sm2TM17 and NdFeB applied have in fact been approximately the same as those of ferrite. Therefore, Sm2TM17 and NdFeB will possess the ability to take the place of ferrite under a certain high frequency AC electric field. 相似文献
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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). 相似文献
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Magnetic properties and intergranular action in bonded hybrid magnets,based on NdFeB and strontium ferrite powders were investigated.The long-range magnetostatic interaction and short-range exchange coupling interaction existed simultaneously in bonded hybrid magnets,and neither of them could be neglected.Some magnetic property parameters of hybrid magnets could be approximately obtained by adding the hysteresis loops of two magnets pro rata. 相似文献
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High performance magnets not only have high magnetic properties, but also have good homogeneity. The homogeneous of Nd14.2DyxAl0.8Cu0.1B6.2Febal. bulk magnets was studied. The sizes of the samples produced by conventional sintering process were 53×50.5×25.3/40.2/50.4/61.0 mm. The magnetic character and microstructure of the samples were determined by NIM-10000H hysteresigraph, optical metaloscope, and SEM respectively. The results show that the Hcj reduces with increasing C content at the same process parameters. And the Hcj shows dependence not only on the ageing processing but also on the size of the bulk and loading capacity etc. The Hcj increases with prolonging ageing time and the ageing time should be different with different size of the bulk. With the increase of the loading capacity, the Hcj reduces promptly and is very inhomogeneous. The microstructure of the samples shows that the grain of the hard magnetic phase is finer and the neodymium-rich boundary is distributed homogeneously with prolonging ageing time. And so is the sample in a small amount of the bulks. 相似文献
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Lü Yousheng 《中国稀土学报(英文版)》2007,25(Z1):125-129
A new alloy of Nd33.5Dy0.99Febal.Al0.52Cu0.1B1.15 (%, mass fraction) was fabricated by powder metallurgy. The effects of Dy, Al and Cu additions on the microstructure and magnetic properties of sintered NdFeB magnet were investigated. The additions of Dy, Al and Cu are effective to refine grains and improve coercivity. Moreover, suitable amounts of Dy, Al and Cu lead to a demagnetization curve with good rectangularity. It is found that the sintered NdFeB magnet has relatively high magnetic performance of Br=12.17kGs, jHc=13.52kOe and (BH)max=34.71MGOe. The sintered NdFeB sample was examined by magnetic force microscope which revealed the domain structures at the surface. It is revealed that the mean Nd2Fe14B grain size is significantly larger than the average scale of the magnetic contrast. An explanation about this is that most Nd2Fe14B grains in sintered NdFeB alloy are dominated with the muhidomain structures when the magnet is in thermally demagnetization state. 相似文献
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本文研究了B和Si的含量及Fe/(B+Si)相对含量对非晶态Fe-B-Si合金退火脆化行为的影响;分析了在常规热处理条件下,利用成分的变化,获得延性与磁性综合性能的可能性。实验结果表明,非晶态Fe-B-Si合金的退火脆化行为具有较大的成分依赖性,位于Fe79at%-81at%,B11at%,Si8at%-9at%成分范围内的Fe-B-Si非晶态合金的退火脆化敏感性最小,脆化仍发生于晶化开始之前... 相似文献
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Dependence of Magnetic Properties of Rapidly Quenching (Nd, Pr)x(FeCoZr)94-xB6 Bonded Magnets on Rare Earths Content 总被引:1,自引:0,他引:1
By using sub-everquenching and annealing method which has a wide processing window, (Nd, Pr)x(Fe-CoZr)94-xB6(x=12, 10.5, 10, 9) bonded magnets were prepared and the effect of rare earths content on magnetic properties was investigated. Being spun at sub-ove, quenching speed the as-spun ribbons consist of amorphous phases mixed with fine crystallites. After crystallization under optimum annealing conditions and bonded with 3.25%(mass fraction) epoxy, the magnets obtained the optimum magnetic properties. The rare earths content directly determines the magnetic properties. With the reduction of rare earths content, Br increases but Hci and (BH)max decrease, x=10 is the critical value for the magnetic properties change. Below this value, Br increases slowly meanwhile Hci and (BH)max decrease strongly because alloy contains extra fractions of soft magnetic phase which are not coupled with the hard magnetic phase. This experimental result is consistont with the calculated results using the model of volume fraction of soft magnetic phase coupled completely suggested. 相似文献