Surface color treatment of alloys with micro-arc oxidation process
Example embodiments include methods of treating a surface of an aluminum (Al) alloy or magnesium (Mg) with an electrolyte to obtain a surface with a coloration that is uniformly enhanced. Example embodiments also include surface-treated Al alloy or Mg alloy made by the example methods.
1. A method of treating a surface of a magnesium (Mg) alloy, comprising:
immersing the Mg alloy into an electrolyte; and
applying an electric current with a current density of 0.03-0.17 A/cm 2 and a pulse frequency of 500-2,600 Hz on the Mg alloy for a time duration of 100-720 seconds,
wherein the Mg alloy comprises:
8.3-9.7 weight percent of aluminum (Al);
0.35-1.0 weight percent of zinc (Zn);
0.15-0.50 weight percent of manganese (Mn); and
a balanced percent of Mg;
wherein the electrolyte is a mixture of 20-30 g/L silicates, 5-20 g/L phosphate, 3-6 g/L hydroxide, 5-10 g/L glycerol, 0.5-2 g/L tungstate, and 5-15 g/L titanium dioxide (TiO 2 ) nanoparticles in deionized (DI) water, and
wherein a color of the surface of the Mg alloy that is treated by the method is uniformly enhanced.
2. The method of claim 1 , wherein the silicate is sodium metasilicate nonahydrate.
3. The method of claim 1 , wherein the phosphate is sodium pyrophosphate decahydrate.
4. The method of claim 1 , wherein the hydroxide is sodium hydroxide.
5. The method of claim 1 , wherein the tungstate is sodium tungstate.
6. The method of claim 1 , wherein the TiO 2 nanoparticle is rutile titanium dioxide with a particle size of 30 nm.
7. A surface-treated magnesium (Mg) alloy, comprising:
a Mg alloy wherein the Mg alloy includes:
8.3-9.7 weight percent of aluminum (Al);
0.35-1.0 weight percent of zinc (Zn);
0.15-0.50 weight percent of manganese (Mn); and
a balanced portion of Mg;
a Mg based ceramic layer that has a thickness of 5-40 μm and that is formed on a surface of the Mg alloy; and
a layer of Titanium (Ti) that is distributed in the Mg based ceramic layer,
wherein the Mg based ceramic layer uniformly enhances a color appearance of the surface of the Mg alloy.
8. The surface-treated magnesium (Mg) alloy of claim 7 , wherein the surface-treated Mg alloy has a sRGB value of ( 97 , 100 , 106 ), ( 69 , 71 , 80 ), ( 104 , 107 , 111 ), ( 164 , 158 , 158 ), or ( 134 , 132 , 134 ).
9. The surface-treated magnesium (Mg) alloy of claim 7 , wherein the surface-treated Mg alloy is made by the method of claim 1 .