Avaliação do efeito dos parâmetros densidade de corrente e temperatura do banho eletrolítico nas propriedades da liga zn-ni-mo obtida por eletrodeposição.

Abstract

Given the significant occurrence of the corrosion process in metallic materials, which leads to considerable financial losses and a decline in the mechanical characteristics of the material, it was necessary to develop a method capable of mitigating the damages caused by this phenomenon. This method aims not only to enhance corrosion resistance but also to improve the material's mechanical properties. One technique that has been prominent for decades involves the creation of a metallic film on a piece, forming a protective layer that reduces the corrosion process. This technique is known as electrodeposition. Due to its simplicity and effectiveness, studies on this procedure have been gaining increasing attention. Electrodeposition allows for the creation of various combinations of metal alloys, with new alloys constantly being investigated to extract the best from each element and combine them, resulting in a metallic coating that meets every day and specialized needs. Consequently, experiments were conducted on the ternary Zn-Ni-Mo alloy to evaluate its optimal parameters during the electrodeposition process, such as current density and temperature. The goal was to obtain the best properties for the alloy under investigation. For the deposition study of the ZnNi-Mo alloy, an electrolytic bath containing nickel sulfate, sodium molybdate, zinc sulfate, sodium dodecyl sulfate, saccharin, and acting as a complexing agent, sodium citrate, was utilized. Temperatures ranging from 30°C to 60°C were studied, with current density varying from 70mA/cm² to 110mA/cm², and the pH of the electrolytic bath was maintained at 7.5. To optimize the operational process and ensure coatings of higher quality, a factorial design (2²) with two central points was employed. The Energy Dispersive X-ray (EDX) technique was used to characterize the coatings in terms of their chemical composition, while Scanning Electron Microscopy (SEM) was utilized to study their morphology. Through this study, it was observed that both current density and temperature directly influence the chemical composition, morphology, and corrosion resistance of the alloy. Experiments conducted using the central points demonstrated the best corrosion resistance results, resulting in a coating surface composed of agglomerated grains with nodular geometry.