▎ 摘　　要

NOVELTY - In presence of pretreated magnesium alloy electrode, platinum electrode as auxiliary electrode, saturated calomel electrode as reference electrode, and electrolyte formed using graphene oxide powder, chronoamperometry magnesium alloy CHI860D electrochemical deposition is carried out at high potential of -0.9 V, low potential of -1.7 V, and pulse width of 100 seconds. After the deposition, the material is dried at 60-70 degrees C for 1-2 hours to obtain magnesium alloy surface oxidation graphene composite coating. USE - Preparation of magnesium alloy surface oxidation graphene composite coating (claimed). ADVANTAGE - The method efficiently provides magnesium alloy surface oxidation graphene composite coating with low current density and high corrosion and electrochemical impedance. DETAILED DESCRIPTION - Magnesium alloy (600# and 1200#) is ground using waterproof sanding paper, polished, washed using water and degreased using alkaline oil at 60-80 degrees C for 0.5-2 minutes. The resultant material is ultrasonically washed using ethanol and deionized water for 5-15 minutes, and cold-dried to obtain pretreated magnesium alloy. The alkaline oil comprises 20-30 g/L sodium phosphate, 15-25 g/L sodium hydroxide and 30-40 g/L sodium carbonate. Solution containing 3 vol.% graphite oxide is washed using dilute hydrochloric acid solution and deionized water to neutral pH, centrifuged resultant suspension at 1000 rpm/minute and lower layer is removed. The mixture is further centrifuged to obtain supernatant. The obtained supernatant is freeze-dried to obtain graphene oxide powder. In presence of pretreated magnesium alloy electrode, platinum electrode as auxiliary electrode, saturated calomel electrode as reference electrode, and electrolyte formed by dissolving 10-30 mg graphene oxide powder in 20 ml aqueous solution of triethanolamine and ultrasonically dispersing, chronoamperometry magnesium alloy CHI860D electrochemical deposition is carried out at high potential of -0.9 V, low potential of -1.7 V, and pulse width of 100 seconds. After the deposition, the material is dried at 60-70 degrees C for 1-2 hours to obtain magnesium alloy surface oxidation graphene composite coating. Sodium phosphate, sodium hydroxide, sodium carbonate, ethanol, hydrochloric acid, triethanolamine and graphite are chemically pure and above purity.