Influence of a CuS04 treatment on atmospheric steel rust formation. A Mössbauer spectroscopy study

Abstract

Mössbauer spectroscopy has been used to analyze the rust layers formed on a weathering steel and a 1010 steel exposed for 10-1/2 months to an urban-industrial atmosphere. No significant difference was found comparing the rusts of both steels: they were composed by γ-FeOOH, superparamagnetic α-FeOOH, and an amorphous or gel-like compound. γ-FeOOH is more abundant in the internal rust layers, whereas the amount of α-FeOOH and the amorphous compound Increase in the external rusts. Part of the samples received an Initial copper deposit by immersion of the steel plates in a CuS04 bath. Mössbauer spectroscopy analysis showed that the amorphous substance was no longer present In the rusts of those specimens; that is, the rusts of both steels were formed only by γ-FeOOH and α -FeOOH.