8:40 AM - ST01.01.03
Nanoporous Gold Thin-Film Dealloying—Process-Structure Correlation
Stanislau Niauzorau1,Aliaksandr Sharstniou1,Natalya Kublik1,Venkata Sampath1,Bruno Azeredo1
Arizona State University1
Nanoporous metals with bi-continuous porosity attracts considerable interest due to its high surface area which opens their potential for use in sensing , catalysis , and energy storage . However, processing-structure (PS) relations for nanoporous gold (NPG) have been largely not understood. Recently, McCue et al. constructed and analyzed a large dataset of porous gold SEM images from various publications to establish correlations between structural parameters (i.e. ligament diameter, aspect ratio, solid area fraction (SAF)), and processing conditions (such as dealloying times and temperatures) . However, the large scatter of this dataset also suggests issues with the reproducibility of NPG synthesis even with the reported fixed dealloying protocol (e.g. precursor alloy composition, etching solution, concentration, etc.). In this study, we experimentally examine the reproducibility of the synthesis of NPG thin films fabricated at constant conditions (i.e. 60 at.% Ag in precursor alloy, 7.85 M HNO3, 65 °C) and extract structural data to find PS relations. Moreover, we test the influence of processing conditions previously not reported such as the temperature equilibration time of the etchant solution, and sample aging effects such as stress release, grain growth and surface oxidation, all of which have been found to affect the uncertainty of NPG synthesis. This ground work may shed more light at future understanding of the kinetics of morphology evolution in chemical dealloying at a more quantitative level.
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