Comparative electrochemical study of Arc- and Flame sprayed Al coatings in marine environment

摘要

Al thermal sprayed coatings were deposited on mild steel substrates using the arc and flame spraying method. The structure of the coatings was examined by scanning electron microscopy (SEM). The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies were carried out on such coatings in artificial seawater (ASW) solution in order to evaluate their corrosion resistance. In summary, thermal arc sprayed coating should be considered to be chosen as a coating for an effective corrosion protection medium. Denser Al coatings prepared using the arc process showed a higher corrosion resistance than that of the flame sprayed coatings. The results showed the significant influence of the microstructure on the corrosion resistance of the coatings, and form a good basis for method selection in different application. So, the corrosion resistance of the Al coatings depended on the spray process. The finer microstructures of the Arc coatings could also play an important role in this.