Consolidation of Sm2Fe17N3 magnets with Sm-based eutectic alloy binder

Kohei Otogawa, Kenta Takagi, Toru Asahi

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    Consolidation of Sm2Fe17N3 powder with a new Sm-based alloy as a metal binder was examined. Investigation of various Sm-based alloys led to the discovery of a Sm-Fe-Cu-Al alloy having a low melting point of 495 °C, which is more than 100 °C lower than the thermal decomposition temperature of Sm2Fe17N3. The metallographic structure of the Sm-Fe-Cu-Al alloy ingot was a SmCu/Sm eutectic structure containing solid-solution Fe, Cu and Al. Pulverized Sm-Fe-Cu-Al powder as a binder was mixed with Sm2Fe17N3 powder, and the mixture was hot-pressed by a current sintering apparatus. The Sm-Fe-Cu-Al alloy binder did not affect the magnetization of Sm2Fe17N3 adversely after consolidation. The binder-added Sm2Fe17N3 hot-pressed compacts successfully maintained the coercivity of the raw powder over a wide range of hot-pressing temperatures, whereas additive-free Sm2Fe17N3 hot-pressed compacts showed a significant decrease in coercivity. Therefore, the Sm-Fe-Cu-Al alloy binder overcame the weakest point of Sm2Fe17N3 magnets. XRD analysis suggested that the Sm-Fe-Cu-Al binder restrained precipitation of the α-Fe phase, which is thought to be the probable cause the decrease of coercivity.

    Original languageEnglish
    Pages (from-to)19-26
    Number of pages8
    JournalJournal of Alloys and Compounds
    Volume746
    DOIs
    Publication statusPublished - 2018 May 25

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    Keywords

    • Coercivity maintenance
    • Low-temperature consolidation
    • Quaternary eutectic alloy
    • SmFeN magnet
    • α-Fe formation

    ASJC Scopus subject areas

    • Mechanics of Materials
    • Mechanical Engineering
    • Metals and Alloys
    • Materials Chemistry

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