• Title/Summary/Keyword: CuNi

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Study of order-disorder transition in Pt-Ni bimetallic alloys

  • Seo, Ok-Gyun;Hwang, Jae-Seong;O, Pil-Geon;Gang, Hyeon-Cheol;Jeong, Hui-Su;Kim, -Chan;Kim, Dae-Gyun;Kim, Yun-Hui;Lee, Su-Ung;Kim, Gi-Ho;Jeong, Geon-Yeong;No, Do-Yeong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.403-403
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    • 2010

  • The Pt-Ni alloy is an electro-catalyst of interest in the low temperature direct methanol fuel cells(DMFCs). It has been already reported that the Pt-Ni alloy catalysts may even have enhanced activity compared to pure platinum catalyst, depending on how the surfaces are prepared. The order-disorder transition in bimetallic alloy such as $\beta$-CuZn, Cu3Au, and CuAu have been investigated greatly by x-ray diffraction. After annealing the bimetallic alloy, the crystal structure changes as observed in the order-disorder transition of Cu3Au which changes from the face centered cubic to a simple cubic structure. Pt-Ni bimetallic alloy has been already reported to have the face centered cubic structure. However, in nano-scale Pt-Ni bimetallic alloy crystals the crystal structures changes to a simple cubic structure. In this experiment, we have studied the order-disorder transition in Pt-Ni bimetallic nanocrystals. Pt/Ni thin films were deposited on sapphire(0001) substrates by e-beam evaporator and then Pt-Ni alloy were formed by RTA at 500, 600, and $700^{\circ}C$ in a vacuum environment and Pt-Ni nano particles were formed by RTA at $1059^{\circ}C$ in a vacuum environment. We measured the structure of Pt-Ni bimetallic alloy films using synchrotron x-ray diffraction and SEM.

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