Efeito da densidade de corrente para obtenção da liga Fe-Mo-P pelo processo de eletrodeposição.

Abstract

Corrosion is a spontaneous process occurring more frequently in aqueous media, in which corrosion is essentially electrochemical. Electrochemical techniques such as Potentiodynamic Polarization is an investigation of the corrosive process; Protective coatings (metallic, polymeric, composite) can be obtained using the electroplating technique and applied to control the corrosive process. The electroplating process has been increasing in recent years by allowing potential coatings to mitigate the damage caused by corrosion. As an example of protective coatings against corrosion, metal alloys obtained by electroplating can be cited. Alloys containing the metal molybdenum can be applied to inhibit or mitigate corrosive processes due to their excellent properties of resistance to corrosion and mechanical wear. The study of the addition of molybdenum in alloys containing less noble-character metals such as iron can improve their mechanical and corrosion resistance properties. Additional elements,

such as phosphorus, can improve the mechanical properties and the corrosion resistance of iron- molybdenum-based alloys. Thus, the objective of this work was to obtain and characterize Fe- Mo-P coatings from the electrodeposition process. For this purpose, an electrolytic bath

consisting of 0.50 M sodium citrate, 0.03 M iron sulfate, 0.09 M sodium molybdate and 0.09 M sodium hypophosphite was developed. The parameters evaluated in the deposition process were current density (30 mA/cm2

and 60 mA/cm2

) at fixed pH 6. The study of the surface of the coatings was carried out by Scanning Electron Microscopy (SEM). In addition, the coatings were characterized by the X-Ray Diffraction (XRD) technique. The corrosion resistance properties of the electrodeposits were evaluated using the techniques of Potentiodynamic Polarization (PP). The corrosion tests were carried out in a saline solution (3.5% NaCl) it was noted that the coating obtained under experimental conditions at 60 mA/cm2

obtained the most positive corrosion potential (-0.5 V) and the highest value of polarization resistance (20.00 Ω.cm2 ), thus presenting the highest resistance to corrosion. Therefore, Fe-Mo-P coatings were successfully obtained following the deposition parameters evaluated here. With their performance against corrosion in saline environment and due to the amorphous character, the alloy has potential for industrial application.