Method for anodizing magnesium products

Abstract

A method for anodizing magnesium products, the method includes the steps of: providing an electrolyte, the electrolyte including a base solution, a blackening agent, and a complexing agent; putting a substrate material as an anode in the electrolyte, and putting another material as a cathode in the electrolyte; and supplying power between the anode and the cathode until a black coating is formed on the substrate material.

Description

Claims

1. A method for anodizing magnesium products, the method comprising the steps of: providing an electrolyte, the electrolyte comprising a base solution, a blackening agent, and a complexing agent;putting a magnesium alloy substrate material as an anode in the electrolyte, and putting another metal as a cathode in the electrolyte; andsupplying power between the anode and the cathode until a black coating is formed on the magnesium alloy substrate material.

2. The method as claimed in claim 1, wherein the base solution comprises alkali, fluoride, and silicate.

3. The method as claimed in claim 2, wherein the alkali comprises at least one item selected from the group consisting of potassium hydroxide, and sodium hydroxide, and concentration of the alkali is from 2 to 25 grams per liter (g/l).

4. The method as claimed in claim 2, wherein the fluoride comprises at least one item selected from the group consisting of potassium fluoride, sodium fluoride, and ammonium fluoride, and concentration of the fluoride is from 1 to 30 grams per liter (g/l).

5. The method as claimed in claim 2, wherein the silicate comprises at least one item selected from the group consisting of potassium metasilicate, sodium silicate, potassium fluosilicate, and sodium fluosilicate, concentration of the silicate is from 1 to 35 grams per liter (g/l).

6. The method as claimed in claim 1, wherein the blackening agent comprises a main blackening agent, the main blackening agent mainly comprises cupric salt, and concentration of the cupric salt is from 0.3 to 9 grams per liter (g/l).

7. The method as claimed in claim 6, wherein the cupric salt comprises at least one item selected from the group consisting of cupric hydroxide, basic copper carbonate, cupric pyrophosphate, and cupric citrate.

8. The method as claimed in claim 6, wherein the blackening agent further comprises an auxiliary blackening agent, the auxiliary blackening agent is oxysalt, and concentration of the oxysalt is from 0.1 to 8 g/l.

9. The method as claimed in claim 8, wherein the oxysalt comprises at least one item selected from the group consisting of nickel nitrate, ammonium molybdate, and ammonium metavanadate.

10. The method as claimed in claim 1, wherein the complexing agent comprises at least one item selected from the group consisting of acid and salt of ammonia, ethylenediamine tetracetic acid (EDTA), citric acid, tartaric acid, ethylenediamine, and trolamine, concentration of the complexing agent is from 0.5 to 20 grams per liter (g/l).

11. The method as claimed in claim 1, wherein the electrolyte further comprises an inhibitor for increase of blackening and preventing corrosion of the substrate material, the inhibitor comprises at least one item selected from the group consisting of thiourea, sodium m-nitrobenzene sulfonate, and methenamine, each of the thiourea, sodium m-nitrobenzene sulfonate, and methenamine including amido, hydroxyl, or nitryl absorbing radicals, concentration of the inhibitor is from 0 to 5 grams per liter (g/l).

12. The method as claimed in claim 1, wherein temperature of the electrolyte is kept between 10 to 60 degrees Celsius (° C.).

13. The method as claimed in claim 1, wherein thickness of the black coating is from 5 to 18 micrometers (μm).

14. A method for anodizing magnesium products, the method comprising the steps of: providing an electrolyte, the electrolyte comprising alkali, fluoride, silicate, cupric salt, oxysalt, and complexing agent;putting a magnesium alloy substrate material as an anode in the electrolyte, and putting another metal as a cathode in the electrolyte; andsupplying power between the anode and the cathode until a black coating is formed on the magnesium alloy substrate material.

15. The method as claimed in claim 14, wherein concentration of the alkali ranges from 2 to 25 grams per liter (g/l), the fluoride from 1 to 30 g/l, the silicate from 1 to 35 g/l, the cupric salt from 0.3 to 9 g/l, the oxysalt from 0.1 to 8 g/l, and the complexing agent from 0.5 to 20 g/l.

16. The method as claimed in claim 14, wherein the complexing agent comprises at least one item selected from the group consisting of acid and salt of ammonia, ethylenediamine tetracetic acid (EDTA), citric acid, tartaric acid, ethylenediamine, and trolamine.

17. An electronic device, wherein the electronic device comprises a substrate made of magnesium alloy and a black coating formed on a surface of the substrate by the method of claim 1.

18. The electronic product as claimed in claim 17, wherein the coating has a thickness in a range of 5 to 18 micrometers (μm).