Raman and Infrared Spectroscopy of Aqueous Corrosion Films on Lead in 0.1M Chloride Solutions

Abstract

The Pourbaix diagram was investigated by examining potentiostatically oxidized lead samples using Raman and infrared spectroscopy. The surface films formed in solution were those predicted by the potential‐pH diagram. In neutral and basic solutions, the film compositions were not as predicted by thermodynamic calculations, although potentiostatic results agreed very well with potentiodynamic polarization curves. Two polymorphs of were found at different potentials in pH7 solutions, the orthorhombic form at low potentials and the tetragonal form above +0.18V vs. NHE. Infrared spectra gave indications that orthorhombic is formed by deposition from solution while tetragonal forms from the reaction of water with the metallic lead surface.