Recrystallization Behavior of MgAl Layered Double Hydroxide Films on Anodized Magnesium Alloys During Phytic Acid Loading

Abstract

MgAl layered double hydroxides (LDHs) films were prepared via an in-situ growth method on anodized AZ31 magnesium alloy. Subsequently, phytic acid (PA) was loaded as a corrosion inhibitor through an anion-exchange process. The structural evolution of the LDHs nanosheets during the loading process was systematically investigated. The structure, morphology, and composition of the films were characterized using field-emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and glow discharge optical emission spectroscopy. The corrosion behavior was evaluated using potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results revealed that during the first four hours of ion exchange in the PA solution, the LDHs nanosheets underwent a fragmentation–recrystallization process. The incorporation of the corrosion inhibitor significantly enhanced both the stability of the LDHs nanosheets and the long-term corrosion protection of the substrate. Furthermore, a recrystallization mechanism for the LDHs nanosheets on the anodized AZ31 Mg alloy is proposed.