Estudo da resistência à corrosão do revestimento a base da liga Zn-Ni obtido por eletrodeposição em aço SAE 1020

Abstract

Concern for the environment and environmental laws increasingly increase the desire to reduce waste disposal costs, with this in mind, a good alternative is the use of metal biodigesters. However, the organic material and the product of the biochemical process reduce the useful life of this equipment. Aiming for good durability and efficiency of this equipment, studies have been carried out to apply coatings with materials that are highly resistant to corrosion through the electrodeposition process. The objective of this study was to evaluate the corrosion resistance of coatings based on the Zn-Ni alloy obtained by electrodeposition on SAE 1020 steel sheet. The process parameters, bath temperature and current density used to obtain coatings with the alloy Zn-Ni were optimized using factorial experimental design and the results analyzed by the Response Surface Methodology (MSR). The Ni-Zn alloy coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical corrosion measurements by Linear Potentiodynamic Polarization (PPL) and Electrochemical Impedance Spectrometry (EIE). The coating with the alloy Zn68.9Ni31.1 at.%, deposited with current density 25 A/cm2 and bath temperature 60oC, presented the best results against corrosion, as it presented the lowest values of corrosion current, thus indicating a less dissolution of the coating.