Effect of metal cations on the corrosion behavior of Ti, Al, Cu-Ni and Al-Brass in chloride solutions

ABSTRACT

The effect of addition of Cu2+, Co2+, Cd2+ and Fe3+ cations to chloride solutions on the potentiodynamic polarization of Al, Ti, Cu- Ni [66-34] and Al-brass was investigated. The study was confirmed by the XPS examination. It was found that Fe3+ ions cause an increase of the corrosion current, i.e. corrosion rate for Al, Ti and Cu-Ni alloy and a decrease at low concentrations [10-5 - 10-4 mol dm-3] for Al-brass. Cu2+ and Co2+ cations increase the corrosion rate of the metals, while inhibition of alloys is manifested at low cations concentration. Cd+2 cations behave as an activator but show slight inhibition at low concentration for Al-brass. The results were interpreted on the basis of exchange reactions causing deposition of the metal cations on the surface of the electrode