| 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 œC 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 œC for 2 hr, the resulting magnetic powders had the high coercivity of ≥ 12.2 kOe. |
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