Coercivity enhancement of HDDR-processed Nd–Fe–B permanent magnet with the rapid hot-press consolidation process

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• 作者：N. Nozawa ; H. Sepehri-Amin ; T. Ohkubo ; K. Hono ; T. Nishiuchi ; S. Hirosawa
• 关键词：Coercivity ; Hydrogenation– ; disproportionation– ; desorption– ; recombination ; Nd– ; Fe– ; B ; Permanent magnet ; Densification ; Nd-rich phase ; Grain boundary
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2011
• 出版时间：January 2011
• 年：2011
• 卷：323
• 期：1
• 页码：115-121
• 全文大小：1334 K

文摘

High coercivity, fully dense anisotropic permanent magnets of submicron grain sizes were produced by rapid hot-press consolidation of hydrogenation–disproportionation–desorption–recombination (HDDR) processed Nd–Fe–Co–B powders. In the hot-press process, the coercivity of the consolidated material showed a sharp minimum prior to full densification. Thereafter, it reached a value 25 % higher than that of the initial powder. Scanning electron microscopy and transmission electron microscopy observations revealed that the variation in H_cJ was caused by a redistribution of Nd along the grain boundaries during hot pressing and that the high coercivity was attributable to the formation of thin, continuous Nd-rich phase along the grain boundaries.