Preparation and characterization of silane/Mg(OH)₂ composite films prepared on flame-retardant Mg-4%Al-1%Ca alloy by steam and spin coatings

Corrosion resistant films were prepared on Mg-4Al-1Ca (ACa41) alloy by steam coating, spin coating, or steam coating followed by spin coating. The chemical and corrosion resistant properties of the films were characterized by using SEM, XRD, FT-IR, and electrochemical methods. XRD patterns revealed that the film prepared by steam coating was composed of crystal Mg(OH)₂ and Mg-Al layered double hydroxide (LDH). FT-IR spectra showed the presence of Si-O, C-H, Mg-O, and Al-O bonds in the film prepared by steam coating followed by spin coating, resulting in the formation of silane/Mg(OH)₂ composite film. Potentiodynamic polarization curves of the film prepared by the two steps coating showed high corrosion resistance, and the corrosion current density of the composite film decreased considerably compared to those of the bare ACa41, the film prepared by steam coating or spin coating.