Mechanistic study of the atmospheric corrosion of BC550 weathering steel in simulated marine environments by in-situ electrochemical noise

Purpose This study aims to investigate the corrosion behavior of BC550 weathering steel in a simulated marine atmospheric environment, with a focus on the accelerating effect of pollutants on the corrosion process. Design/methodology/approach A systematic study was conducted using electrochemical noise (EN) measurements, which enabled in-situ monitoring and real-time investigation of the corrosion process of BC550 weathering steel. The reliability of the EN data was further validated through correlation with weight gain measurements. The corrosion products and rust layer evolution were characterized using X-ray diffraction and scanning electron microscopy. Findings The introduction of pollutants into the marine atmosphere increased the corrosion rate of BC550 weathering steel by approximately 10%, confirming their accelerating effect. The rust layer exhibited distinct color transformations, progressing from orange/yellow to red/brown and finally to black over time. A protective layer formed on the steel surface due to a decrease in β-FeOOH and an increase in a-FeOOH content. Originality/value This study reveals the impact of pollutants on BC550 weathering steel corrosion in marine atmospheres and provides insights into the rust layer’s morphological and compositional evolution. The findings offer valuable guidance for improving corrosion resistance in weathering steel under polluted marine environments.