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The low-aluminum and low-magnesium Zn1.5Al1.1Mg hot-based Zn-Al-Mg alloy coated plate was employed as research object, the initial corrosion mechanism of the cut edges of low aluminum, low magnesium Zn-Al-Mg alloy coated plates was clarified by SEM, EDS, XRD and other methods. Moreover, through SEM and XRD method, the types and morphology of corrosion products at the cut edges of the specimens after immersion and cyclic corrosion experiments were analyzed for evaluating the protective performance of Zn-Al-Mg alloy coatings on their cut edges. Results showed that the cut edge of the Zn-Al-Mg alloy coating was composed of three microstructures: pure Zn phase, Zn-MgZn2 binary eutectic and Zn-MgZn2-Al ternary eutectic. In general, the ternary eutectic and binary eutectic containing MgZn2 phase served as corrosion initiation points during the initial corrosion stage of Zn-Al-Mg alloy cut edges, and then extended to the entire coating. During the long-term corrosion process of cutting edges in Zn-Al-Mg alloy coatings, the Zn element played a major protective role. Specifically, free Zn2+ accumulated at the cutting edge of the coating by forming basic zinc carbonate [Zn5(OH)6(CO3)2] and basic zinc chloride [Zn5(OH)8Cl2·H2O], hindering the longitudinal expansion of the corrosive medium. Nevertheless, when these precipitates transformed into porous ZnO, the protective capabilities of the coating failed, and the cut edge was damaged.

A new type of corrosion-resistant steel (B-NS) for ship hull was developed by adding alloying elements Cu, Cr and Ni according to the corrosion characteristics of marine environment. The corrosion resistance of B-NS was investigated by electrochemical test, full immersion test and dry-wet cyclic test, and the cross-sectional morphology and composition of the rust layer were analyzed by scanning electron microscope and energy dispersive spectroscopy. The results show that the addition of alloying elements effectively reduces the saturated current density and corrosion rate of B-NS steel under full immersion and dry-wet cyclic test. The alloying elements promote the formation of a more stable and dense protective rust layer under dry-wet cyclic test. The alloying elements give B-NS ship plate steel excellent corrosion resistance mainly in improving the thermodynamic stability of B-NS ship plate steel, promoting the formation of rust layer to prevent aggressive media from corroding the substrate, and giving the rust layer cation-selective permeability to prevent Cl- from penetrating into the rust layer.

Alloying control is an effective method to improve the corrosion resistance of low alloy structural steels. Different kinds of alloying elements have different influence law on the corrosion resistance of steels. In order to explore the effective method to improve the corrosion resistance of steel, the distribution law of alloying elements in steel as well as its influence mechanism and law on the corrosion resistance of steels were summarized in this paper. The research direction of regulation of the new generation of corrosion resistant steel in China was prospected. It was expected to provide a theoretical reference for the development of corrosion resistance regulation theory of low alloy structural steel and the research and development of a new generation of corrosion resistant low alloy steel in China.

Detecting corrosion in Q235 steel is crucial for ensuring the safety and maintenance of industrial facilities. In this study, we present a novel approach that combines image recognition techniques with corrosion sensor data to improve both the accuracy and real-time capabilities of corrosion monitoring. Our findings show that integrating image recognition significantly enhances the predictive power of atmospheric corrosion models. This improvement is attributed to the strong correlation between image texture features, contrast, and material corrosion. By integrating diverse data sources, we have developed a rapid atmospheric corrosion evaluation model, Qcorr, for efficient assessment of outdoor Q235 steel corrosion. We believe the Qcorr model will be a valuable tool for practical corrosion detection. [ABSTRACT FROM AUTHOR]

The addition of Ca and Sb in Cr‐bearing steel presents improved corrosion resistance during the field exposure test in a marine atmosphere environment. Through local hydrolysis reactions, Ca and Sb can form CaO, Sb2O3, and Sb2O5 to prevent the intrusion Cl− into the corrosion product film, which improves the protectiveness of the corrosion product film and reduces the corrosion rate. The formation of CaCl2 decreases the relative content of β‐FeOOH and makes the corrosion product film more stable. Due to the inhibition of Sb on the local acidification of corrosion product film, Ca and Cr are able to bond with more hydroxide for generating the corresponding oxides and improving the corrosion resistance of Cr‐bearing steel. [ABSTRACT FROM AUTHOR]