Method for treating surface of magnesium-based metal to give metallic texture thereof

Abstract

A method for treating a surface of a magnesium-based metal is disclosed for realizing a metallic texture of the magnesium-based metal. The method includes a buffing step of chemically polishing a surface of a magnesium-based metal by using a chemical polishing agent containing sodium nitride and sodium citrate; an immersing step of immersing the magnesium-based metal, which has been subject to the buffing step, into a strongly alkaline electrolyte solution of pH 11 or above; and an anodizing treatment step of forming a transparent anodizing film on the surface of the magnesium-based metal by applying current with a current density of 0.01 to 1 A/dm 2 to the magnesium-based metal in the strongly alkaline electrolyte solution.

1 . A method for treating a surface of a magnesium-based metal, comprising:
 buffing the surface of the magnesium-based metal by chemically polishing the surface of the magnesium-based metal;   immersing the magnesium-based metal, which has been subjected to the buffing, into a strongly alkaline electrolyte solution of pH 11 or above; and   performing an anodizing treatment including forming a transparent anodizing film on the surface of the magnesium-based metal by applying current with a current density of 0.01 to 1 A/dm 2  to the magnesium-based metal in the strongly alkaline electrolyte solution.   
     
     
         2 . The method of  claim 1 , wherein the chemically polishing includes chemically polishing the surface of the magnesium-based metal with a chemical polishing agent containing sodium nitride and sodium citrate. 
     
     
         3 . The method of  claim 2 , wherein the chemical polishing agent comprises sulfuric acid, nitric acid, sodium nitride and sodium citrate. 
     
     
         4 . The method of  claim 1 , wherein, a voltage is restricted to 10V or below in the anodizing treatment. 
     
     
         5 . The method of  claim 1 , wherein in the anodizing treatment, the electrolyte solution includes 100 to 300 parts by weight of potassium hydroxide, 0.5 to 50 parts by weight of KF, 5 to 50 parts by weight of NaSiO 4  and 0.1 to 0.5 parts by weight of Al, and the electrolyte solution is maintained at a temperature of 20 to 70° C. 
     
     
         6 . The method of  claim 1 , wherein in the anodizing treatment, at least one of cobalt acetate, potassium permanganate, ammonium sulfide, ferric sulfate, potassium ferricyanide, nickel sulfate, copper sulfate and stannous sulfate is added to the electrolyte solution. 
     
     
         7 . A magnesium-based metal having a surface treated according to a process comprising:
 buffing the surface of the magnesium-based metal by chemically polishing the surface of the magnesium-based metal;   immersing the magnesium-based metal, which has been subjected to the buffing, into a strongly alkaline electrolyte solution of pH 11 or above; and   performing an anodizing treatment including forming a transparent anodizing film on the surface of the magnesium-based metal by applying current with a current density of 0.01 to 1 A/dm 2  to the magnesium-based metal in the strongly alkaline electrolyte solution.   
     
     
         8 . The magnesium-based metal of  claim 7 , wherein the chemically polishing includes chemically polishing the surface of the magnesium-based metal with a chemical polishing agent containing sodium nitride and sodium citrate. 
     
     
         9 . The magnesium-based metal of  claim 8 , wherein the chemical polishing agent comprises sulfuric acid, nitric acid, sodium nitride and sodium citrate. 
     
     
         10 . The magnesium-based metal of  claim 7 , wherein, a voltage is restricted to 10V or below in the anodizing treatment. 
     
     
         11 . The magnesium-based metal of  claim 7 , wherein in the anodizing treatment, the electrolyte solution includes 100 to 300 parts by weight of potassium hydroxide, 0.5 to 50 parts by weight of KF, 5 to 50 parts by weight of NaSiO 4  and 0.1 to 0.5 parts by weight of Al, and the electrolyte solution is maintained at a temperature of 20 to 70° C. 
     
     
         12 . The magnesium-based metal of  claim 7 , wherein in the anodizing treatment, at least one of cobalt acetate, potassium permanganate, ammonium sulfide, ferric sulfate, potassium ferricyanide, nickel sulfate, copper sulfate and stannous sulfate is added to the electrolyte solution.