▎ 摘　　要

NOVELTY - Constructing a fluorescence gradient coating on the surface of a magnesium alloy comprises (i) polishing the magnesium alloy substrate to obtain a rough and bright magnesium alloy, (ii) immersing the rough and bright magnesium alloy into degreasing liquid, carrying out ultrasonic treatment, taking out the magnesium alloy, cleaning and blow-drying to obtain magnesium alloy after ultrasonic treatment, (iii) roughening the surface of the magnesium alloy, (iv) preparing micro-arc oxidation electrolyte, (v) placing the magnesium alloy with the roughened surface in micro-arc oxidation electrolyte, (vi) placing the hydroxy apatite powder, europium oxide, graphene quantum dot powder and silver powder into a stainless steel stirrer and mixing to obtain mixed powder, (vii) prefabricating a coating, (viii) adopting laser as an electron beam source, cladding and scanning to obtain the product. USE - The method is useful for constructing a fluorescence gradient coating on the surface of a magnesium alloy. ADVANTAGE - The method: is not easy to cause local alkalization and hydrogen release; has excellent heat-conducting capability; solve the problem that the degradable magnesium alloy as biological material using degradation speed is too fast; can generate inflammation stimulation to inhibit magnesium alloy surface cell adhesion and growth; does not generate negative effects on the repair of damaged tissues; reduces the coating crack defect number, toughness of laser cladding hydroxy apatite coating and brittleness; and can establish a structure foundation for the biological implantation. DETAILED DESCRIPTION - Constructing a fluorescence gradient coating on the surface of a magnesium alloy comprises (i) polishing the magnesium alloy substrate to obtain a rough and bright magnesium alloy, (ii) immersing the rough and bright magnesium alloy into degreasing liquid, carrying out ultrasonic treatment, taking out the magnesium alloy, cleaning and blow-drying to obtain magnesium alloy after ultrasonic treatment, (iii) taking the magnesium alloy after ultrasonic treatment as anode and a pure platinum sheet as a cathode, immersing the anode and cathode into etching solution, taking out the magnesium alloy after etching, cleaning and blow-drying to obtain magnesium alloy with roughened surface, dissolving sodium bromide, acrylic acid and glycerol into deionized water to obtain etching solution, (iv) dissolving sodium polyphosphate, trisodium phosphate, potassium tripolyphosphate, potassium hydroxide, disodium ethylene diamine tetra acetate, calcium glycero phosphate and disodium calcium ethylene diamine tetra acetate into deionized water to obtain micro-arc oxidation electrolyte, (v) placing the magnesium alloy with the roughened surface in micro-arc oxidation electrolyte, (vi) placing the hydroxy apatite powder, europium oxide, graphene quantum dot powder and silver powder into a stainless steel stirrer and mixing under the conditions that the power of a motor is 60-100W and the rotating speed of a charging barrel is 20-40 rotation /minute (rpm) to obtain mixed powder, (vii) adding a polyvinyl alcohol aqueous solution into the mixed powder and stirring to obtain a paste-shaped mixed solution, wetting the micro-arc oxidation ceramic film layer by using magnesium alloy with the surface containing the micro-arc oxidation ceramic film layer, coating the paste-shaped mixed solution on the surface of the film layer and then placing the film layer into a vacuum drying oven for drying, (viii) adopting laser as an electron beam source, cladding and scanning to obtain the product.