The invention discloses a method for coloring a
magnesium alloy composite film by micro-arc oxidation. The method comprises the following steps: (1)
grinding an AZ91
magnesium alloy, washing with water, washing with alkali, washing with water, cleaning with ultrasonic
waves and washing with deionized water for 2-3 times; (2) placing the AZ91
magnesium alloy serving as an
anode in a micro-arc oxidation
electrolyte and carrying out micro-arc oxidation treatment, wherein the
cathode is stainless steel; (3) dissolving 1-10ml of ethyl
Orthosilicate in 40-50ml of absolute ethyl
alcohol; adding 1-2g of
zirconium oxychloride; magnetically stirring for 0.5-1.5 hours at constant temperature in a 50 DEG C water bath; adding 0.1-0.5g of
copper sulfate pentahydrate and 5-20mg of glucose and continuously stirring for 0.5-1 hour at 50 DEG C; after the liquor is cooled, obtaining a green SiO2-ZrO3
colloid; and (4) immersing a micro-arc oxidation film sample in the SiO2-ZrO3
colloid; soaking; slowly pulling the sample out at a uniform velocity; repeatedly pulling the sample twice;
drying; soaking again; slowly pulling the sample out at the uniform velocity;
drying; then heating to 150-200 DEG C; and curing for 0.5-1 hour. According to the method disclosed by the invention for surface treatment of the
magnesium alloy, a uniform green film with high
corrosion resistance can be obtained.