“Self arranged Cactis” as new goethite morphology from the natural corrosion process of SAE 1020 carbon steel

A new morphology of goethite aggregates (α-FeOOH) obtained through the natural corrosion process of 1020 carbon steel parts exposed to weathering was found. Micrographies obtained by SEM reveal micro and nanostructures with forms of nanosquares, microparticles, nanowires inside microparticles and the unpublished structure of "Self arranged Cactis", all varying between 115 nm and 8 μm. The molecular structure of goethite was characterized by FTIR and elemental analysis of EDX converged with the obtained data. The average corrosion rate for 1020 carbon steel in the weathering was 1.7592 mpy. The data obtained in this work will contribute to the understanding of the corrosion process of 1020 carbon steel, one of the most used in civil construction, as well as in material sciences, where iron oxides are widely used in metallurgy, catalysis and adsorption, and the domain of morphology is fundamental for each application.