The growth and corrosion resistance of MgAl layered double hydroxide films on the surface of LA43M Mg-Li alloy

Abstract

ABSTRACT To investigate the effect of hydrothermal reaction time on the structure and properties of layered double hydroxides (LDH) films on the surface of Mg alloys, LDH films with different time (12, 18, 24, 30, 36 h) were prepared on the surface of LA43M Mg-Li alloy by an in-situ hydrothermal method. The morphology and phase structure of the film were studied by SEM, XRD and FT-IR, and the corrosion resistance of the film was investigated by electrochemical tests, hydrogen precipitation experiments and immersion tests. In addition, the growth mechanism and corrosion resistance mechanism of the LDH film were analysed. It was found that with longer hydrothermal reaction time, the density and thickness of the film were improved. However, excessive prolongation of hydrothermal time leads to poor film density. The hydrogen precipitation experiment showed that the corrosion rate of LDH-24 h is the smallest. The self-corrosion current density of the film prepared at 24 h was three orders of magnitude lower than the matrix. The best growth and performance of LDH was achieved at a hydrothermal time of 24 h.