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| Research on the La/Ce- rich multi- main- phase RE- Fe- B permanent magnetic materials |
| YAN Mi, JIN Jia- ying, MA Tian- yu, WANG Xin- hua |
| School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China |
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Abstract Nd2Fe14B- type sintered magnets with outstanding magnetic performance have served as indispensable components for both the industrial and household products. The continually growing demand for Nd- Fe- B magnets has led to the overuse of critical rare earth (RE) elements including Nd/Pr/Dy/Tb, whereas the abundant and cheap La/Ce are overstocked. Incorporation of La/Ce into the 2∶14∶1- type permanent magnets is beneficial to balance the utilization of RE sources and lower the material cost. On account of inferior intrinsic properties of La2Fe14B and Ce2Fe14B to Nd2Fe14B compound, directly alloying La/Ce into the 2∶14∶1 lattice severely deteriorates the magnetic properties. Here we report high figure- of- merit La/Ce- rich RE- Fe- B permanent magnets based on the new prototype of multi main phase (MMP) approach (mixing the La/Ce- free and La/Ce- rich RE2Fe14B- type components). The RE concentration in the main phase differs a lot either over local regions within an individual grain or across grains. The resultant short- range exchange couplings of local regions within an individual 2∶14∶1 main phase grain, and the long- range magnetostatic interactions among different 2∶14∶1- type grains facilitate superior magnetic performance of MMP magnets. Meanwhile, the La/Ce- rich MMP magnets also exhibit preferable corrosion resistance and mechanical properties, which are also critical criteria when assessing their applicability.
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Received: 07 December 2017
Published: 16 March 2018
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| Fund:National Natural Science Foundation of China |
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Corresponding Authors:
Mi Yan
E-mail: mse_yanmi@zju.edu.cn
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2018, Vol. 25 
