Corrosion behavior of closed-cell AZ31 Mg alloy foam in NaCl aqueous solutions

•Corrosion behavior of closed-cell AZ31 Mg alloy foam is studied.•Mathematical model is established to calculate surface area of closed-cell foam.•The foams possess higher corrosion resistance than commercial AZ31 Mg alloy.

Corrosion behavior of closed-cell AZ31 foam in different concentrations of NaCl solutions is investigated, using commercial AZ31 magnesium alloy as comparison. Mathematical models and expressions are established to calculate surface areas of the foams. Microstructure observation, hydrogen evolution and potentiodynamic polarization are applied to characterize the corrosion behaviors. Results show that foams possess higher corrosion resistance than commercial AZ31 magnesium alloy. In addition, the mathematical models and expressions are confirmed to be simple and effective in calculating surface areas (expose to corrosive medium) of closed-cell metal foams.