Enhanced analysis of nanoporous gold by atom probe tomography

Atom probe tomography (APT) analysis on nanoporous materials is typically a difficult task, owing to their inferior mechanical properties and their complex field evaporation behaviour, compared with solid consolidated materials. A method for pore infiltration by electrodeposition, detailed in this study, makes it possible to prepare APT samples of nanoporous gold (NPG) using conventional FIB processes, and obtain APT data of good quality with high yield. APT analysis of the NPG material, produced by dealloying, reveals detailed compositional variation within the structures of the nanoscale ligaments. Profiles of the ligaments show exteriors rich in Au, with Ag-rich cores that are very close to the original alloy composition. With this approach the extended analysis into NPG and other nanoporous materials becomes practical, using as a foundation for future work the sample preparation and analysis methodology of this study.