▎ 摘　　要

NOVELTY - Preparing rare earth magnesium alloy structure surface composite film layer involves oil removing, primary water washing, micro-arc oxidation, secondary water washing, electrophoresis, three times water washing, drying and solidifying. The micro-arc oxidation electrolyte comprises 10-40 g/L sodium silicate, 5-20 g/L sodium fluoride, 10-15 g/L sodium hydroxide, 1-5 wt.% graphene, 210-30 g/L copper nitrate and 20-50 g/L triethanolamine. The positive current density is 5-15 A/dm2, negative current density is 2-3 A/dm2, positive duty ratio is 25-70%, negative duty ratio is 40-50%, the forward frequency is 200-800 Hz, negative frequency is 300-500 Hz, positive and negative stages are 1 level. The micro-arc oxidation time is 10-20 minutes. The electrophoresis solution is aqueous solution containing acrylate, flatting agent and carbon melanin. The concentration of each component of the electrophoresis solution is 8-15 wt.% acrylic ester, 1.5 wt.% flatting agent and 2.3 wt.% carbon melanin. USE - Method for preparing rare earth magnesium alloy structure surface composite film layer. ADVANTAGE - The prepared rare earth magnesium alloy structure surface composite film layer has high hardness, high bonding strength, and excellent UV aging resistance. DETAILED DESCRIPTION - Preparing rare earth magnesium alloy structure surface composite film layer involves oil removing, primary water washing, micro-arc oxidation, secondary water washing, electrophoresis, three times water washing, drying and solidifying. The micro-arc oxidation electrolyte comprises 10-40 g/L sodium silicate, 5-20 g/L sodium fluoride, 10-15 g/L sodium hydroxide, 1-5 wt.% graphene, 210-30 g/L copper nitrate and 20-50 g/L triethanolamine. The positive current density is 5-15 A/dm2, the negative current density is 2-3 A/dm2, the positive duty ratio is 25-70%, the negative duty ratio is 40-50%, the forward frequency is 200-800 Hz, the negative frequency is 300-500 Hz, the positive and negative stages are 1 level. The micro-arc oxidation time is 10-20 minutes. The electrophoresis solution is aqueous solution containing acrylate, flatting agent and carbon melanin. The concentration of each component of the electrophoresis solution is 8-15 wt.% acrylic ester, 1.5 wt.% flatting agent and 2.3 wt.% carbon melanin. The voltage is 50-80 V and the time is 10-30 seconds. The structure is placed in the drying device at 80 degrees C for 5 minutes, then raising the temperature to 200 degrees C and keeping the temperature for 30 minutes.