• Title/Summary/Keyword: Al-Fe

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Synthesis of Extremely Fine Fe-6Al-9Si Alloy Powders by Chemical-Mechanical Hybrid Process (화학적-기계적 혼성공정에 의한 초미세 Fe-6Al-9Si 합금분말의 합성)

  • Yoon Jong Woon;Lee Kee-Sun
    • Korean Journal of Materials Research
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    • 제15권3호
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    • pp.166-171
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    • 2005

  • Fe-6Al-9Si(N) alloy powders were synthesized by hybrid process of chemical nitrification and mechanical milling. The nitriding treatment on Fe-6Al-9Si alloy powders formed $\gamma'-Fe_4N$ phase on the powders surface. The nitriding-treated powders were pulverized by horizontal high-energy ball milling machine. The longer ball milling time tended to reduce the size of alloy powders. In ball milling for 36h, extremely fine powders with about $7\~9wt\%$ nitrogen were obtained. Through X-ray diffraction analysis on the powders, it was found out that the longer milling time caused a disappearance of the crystallinity of $\alpha-Fe$ in the powders. TEM study confirmed that the powders is comprised of a few tens nano-meter sized crystals, including $\alpha-Fe$ phase with partially $\gamma'-Fe_4N$ phase. Hysteresis curves of the synthesized powders measured by VSM revealed lower saturation magnetization and higher coercivity, which seemed to be attributed to nitrogen-impregnation and severe residual stress developed during the high energy milling. Microstructure observation on the powder annealed at 873 K for 1 h showed 10 to 20 nm sized $\alpha-Fe$ crystal. Such a enhanced crystallinity significantly increased the magnetization and decreased the coercivity, which was attributed to not only the crystallinity but also residual stress relaxation.

  • https://doi.org/10.3740/MRSK.2005.15.3.166 인용 PDF KSCI