Microstructure, corrosion resistance, and antibacterial properties of an Ag/Mg-Al layered double hydroxide coating synthesized in situ on biomedical Mg-Zn-Ca alloy

Abstract A one-step hydrothermal treatment was used to deposit a nano silver-loaded magnesium-aluminum hydrotalcite (Ag/Mg-Al) layered double hydroxide (LDH) coating onto the surface of a Mg-Zn-Ca alloy to improve the corrosion resistance and antibacterial properties of magnesium alloys for biomedical applications. The effect of experimental parameters such as temperature and time on the microstructure, compositions, and corrosion resistance of the Ag/LDH coating during the hydrothermal treatment was investigated to optimize the preparation process. Additionally, the in vitro degradation performance, antibacterial performance and biocompatibility of the coating were evaluated to determine the optimal preparation condition. The results show that when the LDH–NO3– coating is prepared at 110 °C for 10 h, the constituting silver particles (dimensions, 10–30 nm) are obtained, while the corrosion current density and the corrosion rate decrease to 4.41 μA/cm2 and 0.27 mm/year, respectively. The antibacterial experiment demonstrates that the coating effectively inhibits the reproduction of Escherichia coli while offering remarkable biocompatibility.