Developing and testing of a new anticorrosive coating containing algae as a natural inhibitor for preventing marine corrosion of steel

Green algae were tested as a natural additive for a paint formulation based on vinyl chloride copolymer (VYHH) to evaluate its efficiency for protection of steel against corrosion in seawater using spectrophotometry, alternating current (AC) and direct current (DC) electrochemical measurements, visual inspection, and surface analysis. Both suspended and extracted forms of algae were used to achieve optimum performance of the algae-contained coatings. Poorest performance was obtained when algae was added in its suspended form, whereas the extracted form exhibited better performance based on impedance measurements. The data demonstrated that highest protection was obtained at the algae threshold concentration of similar to1. 4 wt%. The scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX) analysis together with visual inspection of coated specimens exposed to the marine environment gave very good support to the electrochemical data.