Effect of 2D nanocrystalline ZnAl-LDHs films with different orientations on anticorrosion performance of magnesium alloys

Abstract

The two oriented 2D nanocrystalline Zn-Al Layered Double Hydroxides films, with c-axis parallel (//) and perpendicular (⊥) to the substrate, have been successfully prepared in situ by a facile hydrothermal crystallization method on the AZ91D magnesium alloy. The as-prepared films showed their uniform and compact structure. In the electrochemical test, the corrosion current density (icorr) of ZnAl-LDHs crystal film with c⊥s in 0.1 M NaCl solution was decreased from 6.78 × 10−4 A/cm2 to 1.65 × 10−7 A/cm2, and the Rct in EIS was increased from 148.7 Ω· cm2 to 4575 Ω· cm2, while that of c//s were only 1.06 × 10−5 A/cm2 and 406.3 Ω· cm2. This result demonstrated the c-axis perpendicular oriented ZnAl-LDHs crystal film greatly limited the penetration of aggressive ions into the underlying metal surface, effectively protecting the metal from corrosion.