▎ 摘　　要

NOVELTY - Corrosion-resistant composite coating on surface of magnesium alloy, comprises magnesium alloy/magnesium aluminum-layered double hydroxide (MgAl-LDH)/aluminum oxide/nickel/zinc-graphene/compact coating, where the compact coating comprises zinc chloride hydroxide-zinc hydroxide carbonate (Zn5(OH)8Cl2-Zn4CO3(OH)6). USE - The composite coating on surface of magnesium alloy is useful in metal surface treatment (claimed). ADVANTAGE - The composite coating has strong bonding force with the magnesium alloy and excellent corrosion resistance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the corrosion-resistant composite coating on the surface of a magnesium alloy, involving (i) treating magnesium alloy with emery sandblasting, cleaning the surface, sandblasting, ultrasonically cleaning with acetone solution, washing the surface with deionized water, air-drying, etching magnesium alloy in sodium hydroxide solution, and air-drying the surface after cleaning with deionized water to obtain a pretreated magnesium alloy, (ii) putting the pretreated magnesium alloy into the reactor, adding aluminum nitrate solution, dripping 65% aqueous ammonia to adjust the pH of the solution to 8-12, reacting at 75-100 degrees C, taking out after air-cooling, rinsing with deionized water and ethanol in turn, and blow-drying with cold air to prepare MgAl-LDH coating grown on the surface of the magnesium alloy, (iii) adding the zinc powder to the graphene oxide solution, ultrasonically stirring, uniformly coating the graphene oxide on the zinc powder and undergoing redox with the surface of the zinc powder, and vacuum-drying to obtain graphene/zinc powder, abbreviated as G/Zn powder, (iv) preparing zinc-graphene/nickel/aluminum oxide mixed powder by mechanically mixing graphene/zinc powder, nickel powder and aluminum oxide powder, cold-spraying the zinc-graphene/nickel/aluminum oxide mixed powder on the MgAl-LDH coating grown on the surface of the magnesium alloy to obtain zinc-graphene/nickel/aluminum oxide/MgAl-LDH coating, polishing. preparing the zinc-graphene/nickel/aluminum oxide coating on the MgAl-LDH coating grown on the surface of the magnesium alloy, which is zinc-graphene/nickel/aluminum oxide/MgAl-LDH/magnesium alloy, and (v) soaking the zinc-graphene/nickel/aluminum oxide/MgAl-LDH/magnesium alloy in sodium chloride solution to form zinc chloride hydroxide-zinc hydroxide carbonate compact coating on the surface of the zinc-graphene/nickel/aluminum oxide coating layer to obtain magnesium alloy/MgAl-LDH/aluminum oxide/nickel/zinc-graphene/zinc chloride hydroxide-zinc hydroxide carbonate, which is the product.