Effects of Cr Concentration on the Morphology and Corrosion Resistance of Ni-Cr Coatings Prepared by the Electrodeposition Process on 25CrMo4 Steel

Authors : Sarra DJEMMAH

Pages : 439-451

Doi:10.31202/ecjse.1209730

View : 66 | Download : 38

Publication Date : 2023-09-30

Article Type : Research Paper

Abstract :In the current study, Ni-Cr coatings with a various Cr concentrations from 0.1% Cr insert ignore into journalissuearticles values(up to 0.4 % Cr); were performed on the 25CrMo4 low steel, using the electrodeposition process. The deposition of the Ni-Cr coatings was carried out at temperature of 30°C , direct current density of 2 A/dm2 for 40 min , and a bath containing a Cr2insert ignore into journalissuearticles values(SO4);3 as source of chromium ions , Cr+. However, the effects of the Cr concentration on the morphology and the quality of the film were investigated. SEM, EDS and XRD analysis were used in order to characterize the Ni-Cr coatings. The SEM morphology analysis exhibited that the Ni-Cr with 0.2% Cr showed the lowest network of cracks and porosity with uniform and compact structure. The corrosion resistance of the Ni-Cr coatings has been investigated in 3.5 wt-% NaCl aqueous solution, using polarization curves and electrochemical impedance spectroscopy. According to the results, it was found that the variation of Cr content in the Ni-Cr coatings greatly affected the microstructure and the corrosion resistance of the coatings. Moreover, the coating developed with 0.2 % of chromium insert ignore into journalissuearticles values(Cr); can give excellent results as to quality , morphology and corrosion resistance in 3.5 wt-% NaCl environment.
Keywords : Ni Cr Coating, 25CrMo4, Cr Concentration, Morphology, Corrosion, Electrodeposition