Potential-pH Diagrams for Pb Adsorption on Cu and Ni Surfaces at 25°C and 300°C

The equilibrium E-pH lines limiting the stability domains of lead adsorbed under the monolayer level onto surfaces of copper and nickel from aqueous solution have been calculated using recent electrochemical data on lead underpotential deposition. Pourbaix diagrams are drawn for Pb adsorption on Cu(111) surfaces at 25°C and polycrystalline Ni surfaces at 25 and 300°C. Besides the interest of such diagrams for surface electrochemistry, the diagram predicting the conditions of Pb adsorption on Ni at 300°C is of interest in the corrosion field, as Pb adsorption in the domain of formation of the passive Ni layer could explain lead-induced stress corrosion cracking which is a cause of life time reduction of Ni-base alloys used in nuclear power plants.