Corrosion Failure Mechanisms of Low‐Hydrogen‐Embrittlement Zn‐Ni Coatings for Engineering Applications: Localized Pitting and Galvanic Effect With Aluminum Alloy

ABSTRACT This study systematically investigates the localized and galvanic corrosion failure mechanisms of low‐hydrogen‐embrittlement Zn‐Ni alloy coatings, a promising eco‐friendly alternative to toxic Cd plating for protecting high‐strength steel. The Zn‐Ni coating prepared at 2 A/dm 2 exhibited the best corrosion resistance, with a dense morphology and a higher charge transfer resistance, and its corrosion rate was 65% lower than that at 5 A/dm 2 . Hilbert‐Huang Transform analysis of electrochemical noise revealed that the 5 A/dm 2 Zn‐Ni coating was more susceptible to localized corrosion than the 2 A/dm 2 coating. However, the coating deposited at 5 A/dm 2 possesses a moderately porous structure that facilitates hydrogen release from the substrate. Furthermore, a galvanic potential reversal with 6062 aluminum alloy was identified, with the 2 A/dm 2 Zn‐Ni coating showing the weakest galvanic effect. This work provides crucial insights for the design and application of Zn‐Ni coatings in engineering structures.