Fe(O, OH)6 network structure of rusts formed on weathering steel surfaces

Abstract

Nano-scale structures of rusts formed on weathering steel surfaces were investigated. It has been shown that the key structure is Fe(O, OH)6 network, which is different from crystalline FeOOH. Atomic structures were analyzed quantitatively by combination of different methods sensitive to middle range order (MRO): x-ray absorption fine structures (XAFS), anomalous x-ray scattering with reverse Monte-Calro simulation, and electron microscopy. It has been shown that Fe(O, OH)6 network structure evolves during the process of corrosion, and a small amount of additional elements change its development and the final morphology of rusts.