Synergistic Construction of Cysteine‐Intercalated LDH Films With Temperature‐Tuned Hydrothermal Growth for Enhanced Long‐Term Corrosion Protection of LA103Z Mg–Li Alloy

ABSTRACT The cysteine‐intercalated layered double hydroxide (Cys‐LDH) composite films were fabricated on LA103Z alloy via a hydrothermal route at different temperatures to achieve enhanced corrosion protection. The influence of hydrothermal temperature on the microstructure evolution, interfacial chemistry, and long‐term corrosion behavior was systematically investigated. The temperature plays a critical role in regulating LDH nucleation, nanosheet growth, and cysteine incorporation, thereby significantly affecting coating compactness and electrochemical stability. The coating prepared at 80°C exhibits the most uniform nanosheet architecture, highest crystallinity, and most compact structure. Electrochemical tests reveal that this coating achieves the highest impedance, largest charge‐transfer resistance, and lowest corrosion current density. Meanwhile, hydrogen evolution and immersion tests confirm its superior durability, with minimal cumulative hydrogen evolution and a stable low reaction rate. The corrosion mechanism analysis demonstrates that the Cys‐LDH system provides synergistic protection through physical barrier effects, chloride ion exchange/capture, and inhibitor‐controlled self‐healing.