Applications of Fourier transform infrared photoacoustic spectroscopy (FT-IR / PAS) to surface and corrosion phenomena

The development of FT-IR / PAS as a surface analytical technique is described by analytical studies presented in this paper. Studies have focused on the use of FT-IR / PAS alone, both qualitatively and quantitatively, and in comparison with X-Ray Photoelectron Spectroscopy (XPS or ESCA) and have yielded a variety of information, especially in the realm of polymer, catalyst and corrosion applications. Spectral information from FT-IR / PAS includes an enhanced surface response and thermal properties convoluted with the normal infrared vibrational absorption function. Analysis of catalyst surfaces provides an example of the unique capabilities of FT-IR / PAS to provide qualitative and quantitative information about both gas phase and adsorbed species. Kinetics of reactions can be followed in real time. The utility of FT-IR / PAS in conjunction with ESCA is illustrated by the analysis of an Fe/NH₃/HCN corrosion product, where unambigous assignment of the resulting compounds allowed explanation for the observed pitting corrosion.