Self-Healing Phenomenon at the Cut Edge of Zn-Al-Mg Alloy Coated Steel in Chloride Environments

Abstract

This study explores the self-healing phenomenon at the cut edges of Zn-Al-Mg alloy coated steel in chloride environments, a critical consideration for materials exposed to marine conditions. Zn-Al-Mg coatings offer superior resistance to cut-edge corrosion. This research aims to unravel the self-healing properties observed in these coatings. Through cyclic corrosion tests (CCTs), we compared the corrosion resistance of Zn-Al-Mg coated steel with traditional zinc alloy coatings. Our findings show a notable reduction in corrosion with ZMA4 coatings after 120 CCT cycles. This is due to the formation of corrosion products, namely layered double hydroxides (LDHs) and Mg(OH)2. X-ray diffraction and X-ray photoelectron spectroscopy analyses were employed to confirm the presence of these products and elucidate their roles in the self-healing process. This study highlights the potential of Zn-Al-Mg coatings for enhancing the durability of steel structures in corrosive environments, suggesting a paradigm shift in corrosion protection strategies for marine applications. The development of coatings that exhibit self-healing capabilities in chloride-rich environments could significantly mitigate the challenges posed by cut-edge corrosion, promising extended service life and reduced maintenance costs.