Corrosion damage in frozen 3.5 wt.% NaCl solution

Zn and frozen 3.5 wt.% NaCl solution were used to simulate galvanized steel structures exposed to the seawater in the Polar Regions. The conductivity of the frozen salt solution and the corrosion of the Zn were characterized by electrochemical impedance spectroscopy, galvanic current measurement, and surface analyses. The results indicated that the completely frozen 3.5 wt.% NaCl solution was still conductive and corrosive, and the galvanic effect between different metals could not be ignored. The corrosion damage risk of metallic structures, particularly in the joint regions, can be high under freezing marine conditions in the Polar Regions. Zn is corroded in the completely frozen 3.5 wt.% NaCl solution and the corrosion accelerated galvanically and locally because of preferential solidification process of the freezing NaCl electrolyte on the Zn surface in some local areas and salt segregation surrounding the preferentially solidified particles.