Infrared and Raman Spectroscopy of Aqueous Corrosion Films on Lead

The use of Raman and infrared spectroscopy to analyze surface films on metals is described. Surface films formed on lead by reaction with aqueous buffer solutions were examined. The composition of each film was determined by Raman spectroscopy while the sample was in the solution. Multiple reflec-tion infrared spectra of dry samples confirmed the Raman results. The Pour-baix diagram for lead in water was calculated, and potentiostatic exposures were conducted to see if the compounds corresponded to those predicted in the diagram. TetragonaI PbO was found to occur over a much greater ange of potentials than thermodynamic stability would indicate. Passive films play an important role in corrosion and other electrochemical phenomena. Passive film studies frequently emphasize either the kinetics of f i lm growth, breakdown, and repair or else they emphasize the structure and composition of the film