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(0, 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.