X-ray microprobe characterization of corrosion at the buried polymer-steel interface

Abstract The simultaneous collection of x-ray fluorescence (XRF) intensity maps for several elements was combined with x-ray absorption near-edge spectroscopy (XANES) to perform a non-destructive study of polymer-steel interfaces exposed to high pH potash brine. Analysis of iron, manganese, potassium and chlorine XRF maps allowed the identification of anodic pits, disbonded areas containing precipitated corrosion products and several cathodic regions. Iron XANES was used to determine the phases of Fe corrosion products present. Our results confirm previous models of corrosion under polymer films where osmotic blisters are causally related to the spread of corrosion at the polymer-metal interface.