Comparative Study on Microstructure, Corrosion Morphology, and Friction Wear Properties of Layered Double Hydroxide/Steam Coating Composite Coatings on Mg–Li Alloy

Abstract

Mg alloy is the preferred material for the lightweight development of manufacturing industry. However, its application is limited due to the poor wear resistance and corrosion resistance. In this experiment, Mg–Al layered double hydroxide/steam coating (LDH/SC) composite coatings are prepared on the surface of LA43M Mg–Li alloy by steam treatment and in‐situ hydrothermal method for different times (12, 18, 24, 30, and 36 h). The morphology and structure of the coatings are characterized by scanning electron microscopy, energy dispersive spectrometry, and X‐ray diffractometer, and the friction wear test of the coatings is carried out. The corrosion resistance of the coatings is evaluated by immersion tests and hydrogen evolution experiments. The effect of hydrothermal time on the growth characteristics, wear resistance, and corrosion behavior of LDH/SC coatings in 3.5 wt% NaCl solution is systematically investigated. In addition, the growth mechanism and corrosion resistance mechanism of the LDH/SC coating are discussed. The results show that the composite coatings is mainly composed of LDH and Mg(OH)2 phases. Appropriately prolonging the hydrothermal reaction time is beneficial to the nucleation and growth of LDH. When the hydrothermal time is 30 h, the prepared coating has the best density, and the prepared coating can significantly improve the corrosion resistance and friction wear properties of the substrate.