Infrared Detection of Atmospheric Corrosion on Metallic Surfaces

The objectiwe of this proposal is to develop a versatile, inexpensive, and portable spectroscopic probe to quantify the atmospheric corrosion of metal surfaces on aircraft. Since many metals form insoluble salts as products of corrosion reactions, it should be possible to monitor the extent of metal corrosion by measuring the surface coverage of these products. For example, aluminum, which is a major component of aircraft, reacts with sulfate ions in acidic solutions to form insoluble aluminum hydroxysulfates. These compounds have distinctive infrared absorptions which can be monitored using infrared reflection absorption spectroscopy (IRAS). IRAS# which involves bouncing an infrared beam off of a reflective surface, is a highly sensitive nondestructive analytical technique for identifying and quantifying adsorbates on metal surfaces. It is capable of providing in situ information about the composition of the top few molecular layers of a surface in liquid or gaseous environments with submonolayer sensitivity.