Materials Transactions Online

Materials Transactions, Vol.58 No.05 (2017) pp.825-828
© 2017 The Japan Institute of Metals and Materials

Improvement of Coercivity of Nd-Fe-B Powder by Nd-Cu Sputtering

Ami Iijima1, Masashi Matsuura1, Nobuki Tezuka1, Satoshi Sugimoto1, Yasuhiro Une2, Hirokazu Kubo2 and Masato Sagawa2

1Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
2Intermetallics Co., Ltd., Nagoya 463-0003, Japan

This paper reports improvement of the coercivity of Nd-Fe-B powder by Nd-Cu sputtering. The total rare earth element content of the Nd-Fe-B powder increased by 0.8 mass% after Nd-Cu sputtering, and the sputtered Nd-Cu was observed at the surface of Nd-Fe-B powder by microstructural observation. The coercivity (Hc) of the Nd-Cu-sputtered Nd-Fe-B powder improved after annealing at temperatures above 600℃, and Hc of the sputtered powder reached a maximum value of 1312 kA m−1 after annealing at 900℃. This Hc value was 470 kA m−1 higher than that of Nd-Fe-B powder without sputtering. Isotropic green compacts were prepared from Nd-Fe-B powders with and without Nd-Cu sputtering, and the sputtering also improved Hc in the compacts. The compact prepared from powder with sputtering had Hc of 630 kA m−1 higher than that of the compact prepared from powder without sputtering after annealing at 900℃. Microstructure observation showed that the improvement of Hc was due to an increase in the Nd-rich phase in the compact by Nd-Cu sputtering.

[doi:10.2320/matertrans.M2016448]

(Received 2016/12/14; Accepted 2017/02/15; Published 2017/04/25)

Keywords: neodymium-iron-boron powder, sputtering, coercivity, neodymium-copper

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