Abstract:
Hot-dip process is one of the most used techniques for the application of metallic coatings with anticorrosive action. The composition of the metal bath to which the substrate will be subjected defines the characteristics that the coating will present. Aluminum, zinc and their alloys are the most suitable for this type of bath. This study evaluated the integrity of aluminum and zinc metal coatings: Galvanized (GI), Galvannealed (GA), Galvalume (GL) and Aluminized through the corrosion resistance measurement in 3.5% NaCl solution, which simulates marine atmosphere, and 1 M H2SO4 solution, which simulates the industrial atmosphere, by means of electrochemical impedance test and potenciodynamic curves. The compositions of the coatings and microstructures were confirmed by MEV and compared with previous studies. All four coatings presented passivation behavior confirming their corrosion resistance, however, Aluminized steel presented better values for potential corrosion and resistivity, confirming its better corrosion resistance compared to the other three coatings. In addition, a significant improvement of the Galvanized steel was observed, which after heat treatment turns into Galvannealed steel.