The Effect of Alloy Composition on The Dealloying of Ni- and Fe-Based Engineering Alloys in Boiling Caustic Solutions

The effect of alloy composition on the dealloying susceptibility of Ni- and Fe-based alloys is studied in near-boiling caustic solutions. A comprehensive comparison of the alloys is performed using electrochemical measurements and nanoscale characterization to evaluate dealloying behaviour. Results indicate a general increase in dealloying resistance when Ni content is increased. In alloys with similar Ni content, higher Cr content delays dealloying, while an increase in Mo content promotes dealloying. Nanoscale characterization confirms a nanoporous surface film with a core–shell ligament structure. The shell is nearly pure Ni, while ligament cores have a composition approaching that of the parent material.