In situ growth and protectiveness mechanism of layered double hydroxide/oxide hierarchical structure on copper alloy in 3.5 wt% NaCl solution

Layered double hydroxide (LDH) coating grown in situ on metals has attracted extensive attention as an efficient way to enhance corrosion resistance. However, work on copper alloys is still lacking. Here, we directly synthesized a LDH-based hierarchical film on copper alloys via incorporating another divalent element Zn in the substrate. Electrochemical tests showed the hierarchical coating acted as a robust anticorrosive surface after a simple hydrophobic treatment by inhibiting the transport of aggressive Cl−, water molecules and oxygen to the bare substrate. The configuration, formation and anticorrosion mechanisms of the hierarchical structure were proposed based on surface and interface analyses.