Investigation of the structure and chemistry of surface layers on metals by x-ray absorption spectroscopy

Most structural metals are very active chemically and without a passivating or protective layer would soon oxidize or corrode. The history of the industry is an attempt to minimize this process. The problem is becoming more acute, particularly in the aerospace industry, where the frames of many older airplanes are lasting longer than their outer skins. A more esoteric effect is the corrosion of metal surfaces in earth orbit by atomic oxygen. This paper is concerned with the structural and chemical characterization by x-ray absorption spectroscopy (XAS) of surface layers on aluminum alloys exposed to salt spray testing and with iron-based A-286 superalloy bolts exposed to atomic oxygen in a low earth orbit