Atmospheric corrosion in sand dust environments is driven by deposits that bear chloride, which sustain thin electrolyte layers on metal surfaces. We established a laboratory protocol to replicate this by extracting, formulating, and depositing a preliminary layer of mixed salts from natural dust onto samples, with humidity precisely set using the salt’s deliquescence behavior. Degradation was tracked with SEM/EDS, 3D profilometry, XRD, and electrochemical analysis. Bare steel showed progressive yet decelerating attack as rust evolved from discrete islands to a lamellar network; while this densification limited transport, its internal cracks and interfacial gaps trapped chlorides, sustaining activity beneath the rust. In contrast, QPQ-treated steel remained largely protected, with damage localized at coating defects as raised rust nodules, while intact regions maintained low electrochemical activity. By coupling salt chemistries derived from the field with humidity control guided by deliquescence and diagnostics across multiple scales, this study provides a reproducible laboratory pathway to predict atmospheric corrosion.

To investigate the corrosion resistance of 60Si2MnA spring steel coated with Zn-Al in a domestic atmospheric environment containing harmful salts, the corrosion environmental factors (temperature, humidity, deposited salts, and pH) were obtained through field research. The deliquescence and weathering behavior of harmful salts were studied using impedance methods to establish their characteristic curves. Additionally, a self-designed salt deposition test apparatus was employed to conduct accelerated atmospheric corrosion tests under constant salt deposition (10 g/m²) and controlled temperature and humidity conditions (20 °C/75% RH and 40 °C/75% RH) over different corrosion periods. The results show that noticeable red rust appeared on the samples after one month of corrosion. As the temperature increased, the consumption of the coating accelerated. XRD and Raman analyses reveal that the main corrosion products of the coating materials were ZnO, Zn(OH)₂, and Zn₅(CO₃)₂(OH)₆, while the red rust primarily consisted of iron oxides and hydroxides. In the early stages of corrosion, the self-corrosion current density was relatively low due to the protective effects of the coating and the corrosion product layer, indicating good corrosion resistance. However, in the later stages, the integrity of the coating and the corrosion product layer deteriorated, leading to a significant increase in the self-corrosion current density and a decline in corrosion resistance. This study provides a data foundation for understanding the corrosion behavior of Zn-Al-coated spring steel in atmospheric environments and offers theoretical insights for developing more corrosion-resistant coatings and optimizing anti-corrosion measures.

The atmospheric corrosion behavior of 60Si2MnA spring steel was investigated in environments containing chloride (Cl ⁻ ) and sulfate (SO ₄ ²⁻ ). Bare steel specimens were exposed to controlled laboratory conditions that replicated key parameters of the target atmosphere. The deliquescence and weathering characteristics of the deposited salts were examined using electrochemical impedance spectroscopy, while a custom-built salt deposition system was employed to conduct corrosion tests at constant temperature and humidity (20 °C/75 % RH and 40 °C/75 % RH) with a surface salt load of 10 g/m ² over varying exposure durations. Pronounced corrosion was observed under both temperature conditions. X-ray diffraction and Raman spectroscopy revealed that the corrosion products were primarily composed of iron oxyhydroxides and iron oxides. Scanning electron microscopy combined with electrochemical analyses showed that, at early exposure stages, the rust layer exhibited abundant cracks and pores, allowing for the ingress of corrosive species. The initial corrosion products acted as strong oxidants, enhancing cathodic reactions and thus accelerating metal degradation. With increasing exposure time, the thickening of the rust layer provided partial protection, slightly improving the corrosion resistance. Elevated temperature was found to significantly accelerate both the corrosion rate and the evolution of corrosion products.