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Evolution of length scales and of chemical heterogeneity during primary and secondary dealloying.

Authors :
Li, Yong
Ngo-Dinh, Bao-Nam
Markmann, Jürgen
Weissmüller, Jörg
Source :
Acta Materialia. Jan2022, Vol. 222, pN.PAG-N.PAG. 1p.
Publication Year :
2022

Abstract

[Display omitted] We study the evolution of silver-rich regions, or 'clusters', during the making of nanoporous gold by dealloying. The clusters, which are remnants of the master alloy that have evaded corrosion, impact the functional behavior of the material. Furthermore, they carry information on the structure size in the initial stages of dealloying. Using kinetic Monte Carlo simulations, we emulate electrochemical dealloying at various electrode potentials. Our simulations illustrate the two-stage character of the process, where primary dealloying generates the initial network of nanoscale ligaments, while the subsequent secondary dealloying is characterized by coarsening and further dissolution. Silver-rich clusters, embedded in essentially pure gold, form during primary dealloying throughout the range of dealloying potentials of the study. At this point, their size scales with that of the ligaments. Both sizes decrease with increasing dealloying potential, and the trends of size versus potential agree with a Gibbs-Thompson type relation. Yet, when coarsening increases the ligament size during secondary dealloying, the size of the silver clusters remains constant. Directly accessing the initial ligament size of nanoporous gold in experiment is challenging, yet our study links this size to that of the silver-rich clusters. The clusters survive even in the later stages of dealloying and their size can be measured. This provides an experimental signature of the initial size. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
13596454
Volume :
222
Database :
Academic Search Index
Journal :
Acta Materialia
Publication Type :
Academic Journal
Accession number :
153960574
Full Text :
https://doi.org/10.1016/j.actamat.2021.117424