Preparation and Characterization of Ni-Ferrite Coating on Carbon Steel Coupons

The effect of the presence of Ni in solution as Ni-EDTA complex in lithiated water at room temperature and pH 10.5 on the formation of ferrite coating on carbon steel surface was studied in an autoclave at 523 K for 12 days at different Ni concentrations with varying amounts of free EDTA. The Ni-ferrite coating was characterized by XRD, SIMS and XPS and also bulk chemical analysis by AAS and UV-visible spectrophotometer. The chemical composition of Ni-ferrite coating showed variation with depth across solution-oxide interface to oxide-metal interface. The content of Ni in the oxide coating on the surface near solution-oxide interface was found to be higher than the average Ni content estimated by analysis after descaling the coating.