Data analysis coupled with microscopic characterization for understanding the potential role of Sn in corrosion behavior

Abstract

In this study, corrosion current data of low-alloy steels with varying Sn contents were collected using corrosion sensors under the atmospheric environment of Guangzhou. The Individual Conditional Expectation (ICE) method was applied to analyze the relationships between corrosion current and exposure time, as well as between corrosion current and temperature. The analysis revealed that Sn microalloying facilitates the rapid stabilization of the rust layer. Furthermore, a critical temperature was identified, beyond which the corrosion rate increases significantly. Notably, Sn was found to mitigate the temperature-induced acceleration of corrosion. Combined with microscopic morphology observations, the rapidly formed corrosion products were found to possess a certain degree of compactness and provide effective protection. Subsequently, the role of Sn was investigated using TEM and micro-Raman spectroscopy. The results revealed that the addition of Sn alters the composition and structure of iron oxides within the rust layer, increasing the proportion of the stable phase α-FeOOH. By influencing the nucleation and growth processes of the rust layer, Sn promotes the earlier formation of a dense and stable protective oxide structure, thereby enhancing the corrosion resistance of the material.