Characterization of Nanostructure of Rusts Formed on Weathering Steel

Nano-scale structures of rusts formed on the weathering steel surface were investigated. It has been shown that the key structure is an Fe(O, OH)6 network, which is different from crystalline FeOOH. Atomic structures were analyzed quantitatively by a combination of X-ray absorption fine structure (XAFS) analysis including in situ observation under wet conditions, X-ray diffraction (XRD), and transmission electron microscopy (TEM). It has been shown that the Fe(O, OH)6 network structure evolves in the process of corrosion and a small amount of alloying elements such as chromium modifies the evolution process and the final morphology of rust.