Crack Mitigation during Dealloying of Au25Cu75

Authors

  • Yi Zhong,

    1. Institut für Werkstoffforschung, Werkstoffmechanik, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
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  • Jürgen Markmann,

    Corresponding author
    1. Institut für Werkstoffforschung, Werkstoffmechanik, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
    2. Institut für Werkstoffphysik und Werkstofftechnologie, Technische Universität Hamburg-Harburg, Hamburg, Germany
    • Institut für Werkstoffforschung, Werkstoffmechanik, Helmholtz-Zentrum Geesthacht, 21502GeesthachtGermany

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  • Hai-Jun Jin,

    1. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, P. R., China
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  • Yulia Ivanisenko,

    1. Institut für Nanotechnologie, Karlsruher Institut für Technologie, Karlsruhe, Germany
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  • Lilia Kurmanaeva,

    1. Department of Chemical Engineering and Materials Science, University of California, Davis, USA
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  • Jörg Weissmüller

    1. Institut für Werkstoffforschung, Werkstoffmechanik, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
    2. Institut für Werkstoffphysik und Werkstofftechnologie, Technische Universität Hamburg-Harburg, Hamburg, Germany
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  • Y.Z. acknowledges support by a Helmholtz-CSC fellowship.

Abstract

The suggested use of nanoporous gold for functional and structural applications requires uniform and specifically crack-free monolithic bodies, ideally with a structure size in the range of 10 nm or below. Here we investigate electrochemical dealloying of two different starting alloys, Au25Ag75 and Au25Cu75, as pathways towards that goal. With an emphasis on the processes that lead to crack formation, we discuss the role of the parameters (i) lattice parameter change, (ii) dealloying potential and rate, and (iii) thermo-mechanical treatment of the master alloys. The Cu-based alloys are found to give superior homogeneity at very small structure sizes, provided that intermediate temperature treatments are avoided. A complete suppression of crack formation was achieved by application of a dealloying potential of 1.1 V versus Ag/AgCl, at a ligament size of 11 nm.

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