Corrosion properties of Ni-Fe-Cr (III) multilayer coating synthesized via pulse duty cycle variation

Ni-Fe-Cr multilayer coatings were successfully electrodeposited on the mild carbon steel. The frequent variation of pulse duty cycle between two values of 20 and 90% prepared multilayers with 8, 16, and 32 bilayers. The results indicate that contents of constituent elements varied in an alternative manner. The corrosion performance of the coatings was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl solution and 0.1 M H2SO4 solution. The results showed that multilayer structure improves the corrosion resistance in comparison to monolithic coatings. Increasing the number of bilayers from 8 to 32 resulted in a consequent increase in the corrosion resistance.