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.