SKM 2021 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 4: Topical Session Interface-Dominated Phenomena - Diffusion
MM 4.2: Vortrag
Montag, 27. September 2021, 15:45–16:00, H2
Silver-rich clusters reveal the initial ligament size during nanoporous gold dealloying via kinetic Monte Carlo simulation — •Yong Li1,2, Jürgen Markmann2,1, and Jörg Weissmüller1,2 — 1Institute of Materials Physics and Technology, Hamburg University of Technology, Hamburg, Germany — 2Institute of Materials Research, Materials Mechanics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
When nanoporous gold is made by dealloying Ag-Au, residual silver forms clusters that impact the material’s functional properties. We point out that the clusters carry information on the geometry of the initial nanoscale network. Using atomistic kinetic Monte Carlo simulation, we studied the evolution of silver-rich clusters and ligament size for dealloying at various potentials. Our simulations demonstrate that dealloying involves two distinct stages. Primary dealloying generates the initial ligament network, while secondary dealloying brings coarsening of the ligaments and further dissolution. During primary dealloying, the sizes of clusters and ligaments are constant over time and they decrease with increasing dealloying potential with a Gibbs-Thompson type relation. At this stage, the ratio between ligament size and clusters size is 1.30±0.07 and independent of the potential. During secondary dealloying, the ligament size (L) for dealloying with various potentials converge to a common coarsening law, L∝ t1/4. By contrast, the silver-clusters size still remains constant. That observation establishes that the surviving clusters provide a way to measure the initial ligament size.