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Development of Low Cost Rare-earth Permanent Magnets With High Energy Products

高能产品低成本稀土永磁体的开发

基本信息

批准号：
01850161
负责人：
HOMMA Motofumi
金额：
$ 6.21万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

项目摘要

The purpose of the present investigation is to develop the low cost R-Fe-B permanent magnets in selectiing the low cost R elements among available various rare-earth elements. Good candidate rare-earth elements for this purpose is the family of so called "didymium" which is the mixture of Nd, Pr, and Ce. The didymium is then abundant and inexpensive. One might say that a mischmetal will be also abundant and inexpensive, and is the good candidate for low cost R-Fe-B magnets. But it is reported that La, which is the main constituent of mishmetal, does not form the R Fe B compounds. Thus, didymium will be better candidate.The best magnetic properties obtained in present studies are Br=13.2kG, Hc=10.2kOe, and (BH)max=320kJ/m(40MGOe) with Fe33.5%-(5%Ce-didymium)-1%B alloy. Temperature dependence of iHc of5%Ce-didymium and didymium alloys arealmost same as that of the Fe-33.5% Nd-1%B alloy.Ce play an important role in densification of the alloy as sintering aid, and in lowering the melting point of (NdPr) Fe B compounds and making it possible to sinter at relatively low temperatures of 104'C. Economically, 40%Ce-didymium alloys are most inexpensive, and give the energy products of 27MGOe, but have the high temperature coefficient. The iHc of 40%Ce- didymium alloy decrease rapidly, by about 65% of iHc of the room temperature, at 100'C. Alternatively, 5%Ce-didymium-Fe-B sin ter-ed magnets with (BH)max=320kJ/m, are most promising among the present studied low cost alloys.Didymium-Fe-B magnet alloys are also available magnetic powders for bonded magnets.

本研究的目的是开发低成本的R-Fe-B永磁体，以便在现有的各种稀土元素中选择低成本的R元素。为了达到这个目的，很好的候选稀土元素是所谓的“Dy”系列，它是Nd、Pr和Ce的混合物。那时，铟是丰富的，而且价格低廉。有人可能会说，混合稀土也将是丰富和廉价的，是低成本R-Fe-B磁体的良好候选者。但据报道，La是混合金属的主要成分，不形成R-Fe-B化合物。本研究获得的最佳磁性能为：含Fe33.5%(5%Ce-DiDyum)-1%B合金的BR=13.2 kg，Hc=10.2kOe，(BH)max=320kJ/m(40MGOe)。5%Ce-Dy及Dy合金的IHC对温度的依赖关系与Fe-33.5%Nd-1%B合金的IHC几乎相同。Ce作为烧结助剂对合金的致密化、降低(NdPr)Fe-B化合物的熔点和在104℃的较低温度下烧结具有重要作用。在经济上，40%Ce-Dy合金最便宜，其能量积为27MGOe，但温度系数较高。在100℃时，40%Ce-Dy合金的IHC迅速下降，约为室温IHC的65%。另外，5%Ce-Dy-Fe-B磁体(BH)max=320kJ/m是目前研究的低成本合金中最有前途的。Dy-Fe-B合金也是粘结磁体的磁粉。