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放电等离子烧结-热变形技术制备NdFeB永磁材料 总被引:1,自引:1,他引:0
采用放电等离子烧结(SPS)方法烧结HDDRNdFeB粉末,研究烧结温度对制备NdFeB永磁材料密度和磁性能的影响。随着烧结温度在650~900℃范围内升高,剩磁、内禀矫顽力及最大磁能积均呈现先升后降的趋势。800℃烧结所获得磁体的磁性能最佳:Br=0.78T,Hcj=577kA/m,(BH)max=78kJ/m3,其致密度达到了99%。微观组织、XRD图谱及磁性能均表明800℃烧结的磁体出现了一定程度的各向异性。900℃烧结时,晶粒长大明显。进而选择具有最佳磁性能的磁体在800℃进行热变形(HD)处理,制备出各向异性磁体。热变形制备的磁体中,大部分晶粒为扁平片状且c轴取向与热压方向一致;少量异常长大晶粒会使细小Nd2Fe14B晶粒的c轴偏离压力方向。各向异性磁体沿c轴的磁性能为:Br=1.09T,Hcj=384kA/m,(BH)max=114kJ/m3。 相似文献
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应用粉末注射成型(PIM)烧结技术制备了锶铁氧体辐射环,并对其微观组织、磁性能、脱脂及烧结工艺进行了研究.结果表明,粉末注射成型样品采用溶剂脱脂、热脱脂和烧结工艺处理后,得到的辐向取向永磁环脆性降低,开裂明显减少,环形保持良好.其密度达到4.89 g/cm3,磁性能参量如下:剩余磁感应强度Br为0.398 T,内禀矫顽力Hcj为236.8 kA/m,最大磁能积(BH)max为29.2 kJ/m3,该磁性能水平与传统粉末冶金磁体的磁性能相当,将注射成型烧结技术应用于永磁铁氧体的制备具有很好的应用前景. 相似文献
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NdFeB粘结磁体的使用温度及磁性能 总被引:3,自引:0,他引:3
对磁粉进行表面处理,利用冷、热模压法制备了金属基及塑料基两种粘结NdFeB磁体,研究了表面处理前后及不同基体磁体的使用温度和磁性能.研究结果表明磁粉的表面处理可以提高磁体的磁性能及使用温度,塑料基磁体的磁性能低于金属基磁体的,但其使用温度却较高,可达180 ℃左右. 相似文献
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采用放电等离子烧结及后续热变形技术制备各向异性Nd-Fe-B磁体,研究烧结温度对放电等离子烧结Nd-Fe-B磁体微观组织和磁性能的影响。随着烧结温度在650~900°C范围内的升高,烧结态Nd-Fe-B磁体的剩磁、内禀矫顽力及最大磁能积呈现先升后降的趋势。在800°C下烧结所获得磁体的磁性能最佳。随后,对800°C烧结后具有最佳磁性能的磁体采用放电等离子烧结技术进行后续热变形处理。与初始吸氢-歧化-脱氢-再复合粉末和烧结态磁体相比,热变形磁体拥有更显著的各向异性和更好的磁性能。当热变形温度为800°C且压缩比为50%时,热变形磁体中的Nd2Fe14B晶粒呈扁平片状且不发生异常长大;磁体沿热压方向具有最佳的磁性能:Br、Hcj和(BH)max分别为1.16 T、449 k A/m和178 k J/m3。 相似文献
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分别采用热等静压烧结法和两步法制备了Nd33Dy0.8Fe64.5Al0.5B1.2汽车电机用稀土永磁材料,并对其显微结构和磁性能进行了测试分析。结果表明,与热等静压烧结法相比,采用两步法制备的试样具有更高的磁体密度、更好的晶粒取向度、更细小均匀的微观组织和更好的室温磁性能。 相似文献
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研究采用放电等离子烧结(SPS)技术制备了掺杂不同含量的La-Ce-Cu合金的Nd-Fe-B热变形磁体;研究了掺杂量对磁体磁性能和微观结构的影响。结果表明,随着掺杂量的增加,热变形Nd-Fe-B磁体的矫顽力先增加后降低;而剩磁与磁能积均有所下降。磁体的矫顽力在掺杂量为1%(质量分数)时,达到最大值为1257kA/m。微观分析表明,掺杂合金中的La元素倾向于分布在富稀土相中,不易进入主相晶粒;而Ce元素则易取代Nd进入主相晶粒中。 相似文献
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基于热变形技术,研究制备了DyF3掺杂热变形NdFeB磁体的微观结构和磁性能。结果表明,通过热变形,磁体获得了具有明显C轴取向特征的扁平形状晶粒,其剩磁从前驱体烧结磁体的0.77 T提高至 1.34 T,提升了近74%。此外,热变形过程起到了晶界扩散的作用,使得DyF3进一步扩散至NdFeB主相之中,形成了(Nd, Dy)2Fe14B相,从而减小了因热变形带来的矫顽力损失。电化学测试表明,热变形过程可提高磁体腐蚀电位和减小电流密度。变形条件800 ℃/70%时,磁体具有最佳的综合磁性能和电化学性能,其磁性能可达:Br=1.34 T,Hcj=1225 kA/m和(BH)max=286 kJ/m3。 相似文献
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热锻PrFeBCu永磁合金 总被引:1,自引:0,他引:1
本文主要通过热锻形变工艺制取各向异性PrFeBCu稀土永磁材料,研究热锻工艺和后道热处理对铸造PrFeBCu合金永磁性能和组织的影响。热锻PrFeBCu合金永磁性能可达到:(BH)max=169.6K/m^3,JHc-960kA/m,它们与成分,形变和热处理工艺等因素有关。 相似文献
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CHEN Zhongmin SHI Zhengxing WANG Leyi FU Hengzhi Northwestern Polytechnical University Xi''''an China 《金属学报(英文版)》1992,5(11):357-363
The hot deformation process of cast Pr_(19)Fe_(74.5)B_5Cu_(1.5) magnets were studied.It isfound that the easy-axes are aligned parallel to the compressive strain direction in vari-ous hot deformation process.During hot deformation,the crushing of Pr_2Fe_(14)B matrixgrains and the relative slip and rotation between the grains take place and the Pr-richmelt is squeezed out of the magnet,leading to a fine,dense and well-aligned microstruc-ture in the fully-deformed magnets.Magnetic properties of B_r=990 mT,_iH_c=880kA/m and(BH)_m=191 kJ/m~3are obtained.The increase of coercivity is attributed tothe fine Pr_2Fe_(14)B grains and the thin Pr-rich phase layer continuously distributed atthe grain boundaries.The increasing remanence is resulted primarily from the develop-ment of the easy-axis alignment as well as from the densification of the Pr_2Fe_(14)B matrix.The easy-axis alignment is developed by the relative slip and rotation of the crushedPr_2Fe_(14)B grains.A full and slow hot deformation is necessary for the good easy-axisalighnment and high magnetic properties. 相似文献
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综述了NdFeB粘结磁体粉末材料制备技术研究的主要进展.介绍了NdFeB粘结磁粉的主要制备方法及其工艺特点,讨论了不同制备工艺以及添加微量合金元素对NdFeB合金磁粉材料微观组织结构和磁性能的影响.在此基础上,指出了进一步提高NdFeB粘结磁体材料磁性能的可能途径及今后研究工作的方向. 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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Choong Jin Yang Ph.D. Ranjan Ray Ph.D. 《JOM Journal of the Minerals, Metals and Materials Society》1989,41(9):42-45
A rapid solidification melt spinning technique has been developed to produce amorphous powders of Fe-Nd-B alloys modified with hafnium diboride. The amorphous powders are consolidated by the hot extrusion technique into bulk magnets of various cross sections. Consolidated magnets show ultrafine grain structure stabilized by ultrafine submicron hafnium diboride particles. The extruded magnets develop strong texture-induced magnetic anisotropy which leads to attractive energy product values of up to 16MGOe. Significant improvement in coercivity is also achieved due to ultrafine grain structure of the extruded magnets. 相似文献