Production and characterization of metallic Cu-Sn alloy coatings in electrolytic bath containing glycine: preliminary exp

ABSTRACT The problems related to corrosion are frequent and may occur in many areas, such as the chemical, petrochemical, naval, civil construction and automobile industries, among other productive sectors. Therefore, corrosion prevention methods should be employed to avoid loss of materials and the use of metallic coatings has served well for this purpose. The production of metallic coatings allows a modification on the substrate surface leading to the formation of a functional material that presents the desired properties and characteristics, in this case, corrosion resistance. However, these coatings are generally produced using toxic cyanide-based baths, which increases the cost of the process due to further treatment of the generated wastes. The present work proposes an initial study aiming at producing of Cu-Sn alloy coatings, with anticorrosive properties, originated from a less aggressive electrolytic bath, presenting different copper and tin ionic concentrations. The coatings were electrodeposited on carbon steel substrate using an acidic electrolyte containing CuCl2, SnCl2 and glycine. These coatings were further characterized by scanning electron microscopy (SEM), X-ray spectroscopy energy dispersive (EDS), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results of EIS showed that the films produced with higher copper contents presented an increase in the values of the charge transfer resistance (Rct). However, the polarization experiments showed that these films did not act as protective coatings. The morphological analysis evidenced the formation of porous coatings, which may explain their poor electrochemical behavior.