Dealloying of Al₂CuMg in alkaline media

The anodic behavior of Al₂CuMg (S-phase) samples in 0.1 M NaOH solution was investigated. Critical potential behavior typical of dealloying was observed while sweeping the potential from open circuit in the anodic direction. Theoretical estimates based on curvature effects in alloy dissolution suggested the development of a porous structure with 2 nm average ligament size during the initial stages of the dealloying process. A delicate balance between metal dissolution, ion solubility, and mass transport in the electrolyte appears to govern the kinetics of the `pit' growth process. A bicontinuous dealloyed microstructure containing flatter regions showing `Swiss cheese'-like morphology, was observed as a result of long-term dealloying.