Effects of various anode materials on the corrosion resistance of calcareous films deposited with an oyster shell waste-recycled solution

Abstract

The favorable role of calcareous coatings that improve the effectiveness of cathodic protection in submerged marine struc-tures is generally recognized. However, although selection of anode materials has a significant effect on deposits, related studies have not been conducted extensively. Further, a method of supplementing calcium, which is the main component of calcareous film, in seawater has not been investigated. Thus, in this study, the calcareous films were electrodeposited using four anodes of STS, Al, Zn, AZ31 in the Ca(HCO3)2 solution where calcium hydrogen carbonate was prepared from oyster shell waste. The surface morphology, structure, and elemental composition analyses of the calcareous films were conducted through X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS), respectively, and corrosion resistance was evaluated through 3% NaCl immersion test and anodic polarization experiments. Consequently, it was determined that the corrosion resistance of the calcareous thin film using Mg was higher than others.