Enveloping Fe–12%Al atomized powders in selectively-oxidized insulating films for soft magnetic composite (SMC) cores

K. D. Choi, S. H. Kim, P. W. Jang, W. Y. Yoon, J. Y. Byun

    Research output: Contribution to journalArticlepeer-review

    19 Citations (Scopus)

    Abstract

    Fe-12 wt%Al gas atomized powders were enveloped in a uniform Al2O3-containing oxide film by heat-treatment of a mixture of Fe–Al and Mg(OH)2 powders at 900 °C for 1 h in static hydrogen atmosphere. In this novel method using a semi-closed system without adding any oxidants, water vapor generated by decomposition of Mg(OH)2 was used as an oxidant to selectively oxidize aluminum in the Fe-12 wt%Al alloy. Most of the generated water vapor was consumed to form the Al2O3 film and the thickness of the insulating film could be controlled in the tens of nanometers range by controlling the amount of added Mg(OH)2 in the mixture. Fe–12%Al powders enveloped in around 50 nm thick oxide films could be applied to make reasonably high-performance soft magnetic composite cores, because the high temperature heat-treatment up to 900 °C was possible and hence easily relieved the strain energy generated when shaping the cores.

    Original languageEnglish
    Article number157241
    JournalJournal of Alloys and Compounds
    Volume854
    DOIs
    Publication statusPublished - 2021 Feb 15

    Bibliographical note

    Funding Information:
    This work was supported by an internal project of Korea Institute of Science and Technology ( 2E30710 ) and the National Research Council of Science & Technology (NST) grant by the Korea government ( MSIT ) (No. CAP-16-10-KIMS ).

    Publisher Copyright:
    © 2020 Elsevier B.V.

    Keywords

    • Fe-12 wt%Al alloy
    • Oxide insulation
    • Selective oxidation
    • Soft magnetic composites (SMCs)

    ASJC Scopus subject areas

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

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