Effect of Ion‐Exchange Temperature on the Microstructure and Corrosion Resistance of Aspartic Acid‐Modified MgAlCa–Layered Double Hydroxide Coatings on LA103Z Mg–Li Alloy

Magnesium–lithium (Mg–Li) alloys are ultralight structural materials widely employed in aerospace and defense, but their applications are hindered by inadequate corrosion resistance. Layered double hydroxides (LDHs) have attracted considerable attention as effective coatings for improving corrosion resistance. This study investigates the influence of ion‐exchange temperature (70°C, 80°C, 90°C, and 100°C) on MgAlCa–LDH coatings intercalated with aspartic acid (ASP), an organic corrosion inhibitor. The coatings were synthesized in situ on LA103Z Mg–Li alloy via a hydrothermal method. The precursor MgAlCa–LDH coating was first fabricated at 100°C for 12 h, followed by ASP intercalation through ion exchange at the selected temperatures for 9 h. The coating synthesized at 90°C exhibited a uniform and dense structure composed predominantly of vertically aligned nanosheets, with an average thickness of 7.4 ± 0.4 μm, indicating superior structural compactness. Long‐term immersion tests (216 h) confirmed its superior durability, with only minimal pitting compared to the extensive damage observed in coatings prepared at other temperatures. Fourier transform infrared spectroscopy analysis confirmed the successful intercalation of ASP within the LDH structure. The corrosion protection mechanism involves ASP/Cl − ion exchange, the formation of protective complexes on exposed metal surfaces, and LDH dissolution–reprecipitation processes that promote self‐healing. An ion‐exchange temperature of 90°C was identified as optimal for fabricating ASP‐modified MgAlCa–LDH coatings with superior corrosion resistance on Mg–Li alloys.