Investigation of the specific adsorption of HSO4-(SO42-) and Cl- ions on Co and Fe by radiotracer technique in the course of corrosion of the metals in perchlorate media

The adsorption of sulphate and chloride ions on Co and Fe was studied in 0.5 mol dm-3 NaClO4 supporting electrolyte at various pH values by radiotracer technique in the course of the corrosion (dissolution) of the metals. The effect of the reduction of ClO4- ions (leading to the formation of Cl- ions) on the radiotracer measurements was investigated. It was found that the adsorption of chloride and sulphate ions occurs in different pH ranges. This phenomenon was explained by the assumption that the adsorption strength of the two species is very different on oxide covered and 'pure' metal surfaces