A multi-step dealloying method to produce nanoporous gold with no volume change and minimal cracking

We report a simple two-step dealloying method for producing bulk nanoporous gold with no volume change and no significant cracking. The galvanostatic dealloying method used here appears superior to potentiostatic methods for fabricating millimeter-scale samples. Care must be taken when imaging the nanoscale, interconnected sponge-like structure with a focused ion beam, as even brief exposure caused immediate and extensive cracking of nanoporous gold, as well as ligament coarsening at the surface. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.