Fabrication of surface-porous Mg–Al alloys with different microstructures in a neutral aqueous solution

Abstract Surface-porous Mg–Al alloys with different microstructures were fabricated via a new method of electrochemical dealloying in a neutral 0.6M NaCl solution. A bimodal porous structure with 47.57 ± 11.43 μm large pores and 265.60 ± 78.68nm honeycomb-like fine pores was obtained by direct electrochemical dealloying of as-cast Mg80Al20 alloy. Following annealing, the eutectic structure disappeared and a bicontinuous, single-sized, porous structure with 7.10 ± 1.96 μm ligaments was created by an annealing-electrochemical dealloying approach. The porous formation mechanism is governed by selective dissolution of the α-Mg phase, which leaves the Mg17Al12 phase as the porous layer framework.