Purpose This paper aims to investigate the impact of high-frequency dry-wet alternation on the corrosion behavior of 921A steel in the marine splash zone. Design/methodology/approach This study used a multifactor coupled comprehensive testing apparatus to conduct an eight-day accelerated simulated corrosion test by regulating the dry-wet ratio and splash frequency. The corrosion characteristics of the material and its underlying mechanism were evaluated using methods including corrosion weight loss testing, surface and cross-sectional morphology observation, phase analysis of corrosion products and electrochemical testing. Findings The results show that under the condition of the same splash frequency, the corrosion rate first increases and then decreases with the increase of the dry-wet ratio; while when the dry-wet ratio is fixed, the corrosion process intensifies as the splash frequency increases. A moderate dry-wet ratio (4:1) combined with high-frequency splashing tends to form a typical gas/liquid/liquid film three-phase interface, which enhances cathodic reactions and induces the formation of corrosion peaks. In contrast, excessively high or low dry-wet ratios and low-frequency conditions are conducive to the formation of a denser and more continuous rust layer structure. Electrochemical test results indicate that the variation trend of corrosion current density is positively correlated with the corrosion rate. Originality/value Using a self-developed multi-factor coupled corrosion testing device, this study systematically investigated the synergistic effects of dry/wet cycles and splash frequency on the rust-layer evolution, electrochemical corrosion processes and corrosion-region distribution patterns of 921A steel under simulated marine splash-zone conditions. The results are of great scientific significance for revealing the dominant corrosion mechanisms under multifactor coupled interactions in the marine splash zone.
Gao et al. (Wed,) studied this question.