Rev.Adv.Mater.Sci. (RAMS)
No 2, Vol. 28, 2011, pages 134-140

IMPROVEMENT OF THE MAGNETIC PROPERTIES OF Nd2Fe14B POWDERS BY DYSPROSIUM DIFFUSION

Moonhee Choi, Donghwan Kim, Jihun Yu and Yangdo Kim

Abstract

Dysprosium powders were diffused into Nd2Fe14B magnetic powders to improve their magnetic properties. Initial powders, Nd12.5Ga0.3Nb0.2B6.4Febal. alloys, were prepared by HDDR process. For diffusion, DyHx powders were pulverized by zirconia-ball under Ar gas for 5-20 hours. The powders were mixed at a ratio of DyHx:Nd2Fe14B=3.4:96.6 and heated to 700-800 úC under vacuum (≤10-6 torr) for 0.5-16 hours. Their magnetic properties were then measured by VSM, Phases and resulting microstructures were analyzed by XRD and SEM-EDX. The optimum diffusion condition occurred with heating to 800 úC for 2 hr, the resulting magnetic powders had the high coercivity of ≥ 12.2 kOe.

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