A method for forming a film on a magnesium alloy surface, the film formed by the method, and a magnesium alloy substrate having the film.

Abstract

This invention relates to a method for forming a film on a magnesium alloy surface. The method includes the following steps: immersing a magnesium alloy substrate in a forming solution and electrically connecting the substrate to the positive terminal of a power source; and applying a voltage of 2V to 10V to the substrate to induce an electrochemical reaction in the forming solution to form the film. The forming solution contains 0.1 M to 0.3 M KMnO4, 0.01 M to 0.05 M Ce(NO3)3·6H2O, and 0.01 M to 0.05 M K2HPO4, and has a pH of 10 to 12. This invention also provides the film formed by this method and a magnesium alloy substrate having the film. The film on the magnesium alloy surface obtained by this method exhibits excellent corrosion resistance and self-healing capabilities, thereby further improving the long-term corrosion resistance of the film under practical application conditions.

Claims

1. A method for forming a film on the surface of a magnesium alloy, characterized by comprising the following steps: immersing a magnesium alloy substrate in a forming solution and electrically connecting the magnesium alloy substrate to the positive terminal of a power source; and applying a voltage of 2V to 10V to the magnesium alloy substrate to cause an electrochemical reaction in the forming solution to form the film; wherein, The formation solution contains 0.1 M to 0.3 M of KMnO4, 0.01 M to 0.05 M of Ce(NO3)3·6H2O and 0.01 M to 0.05 M of K2HPO4, and has a pH of 10 to 12.

2. The method for forming a film on a magnesium alloy surface as described in claim 1, wherein, During the process of immersing the magnesium alloy substrate in the formation solution, the temperature of the formation solution is maintained between 15°C and 35°C.

3. The method for forming a film on a magnesium alloy surface as described in claim 1, wherein, The voltage of 2V to 10V is applied for 30 to 120 seconds.

4. The method for forming a film on a magnesium alloy surface as described in claim 1, wherein, A voltage of 3V to 5V is applied to the magnesium alloy substrate.

5. The method for forming a film on a magnesium alloy surface as described in claim 1, wherein, The formation solution contains 0.1 M to 0.2 M of KMnO4, 0.01 M to 0.02 M of Ce(NO3)3·6H2O and 0.04 M to 0.05 M of K2HPO4.

6. The method for forming a film on a magnesium alloy surface as described in claim 1, wherein, The pH of the solution is between 10 and 10.

5.

7. A film, characterized in that the film is formed on the surface of a magnesium alloy and is prepared by means of forming a film on the surface of a magnesium alloy as described in any one of claims 1 to 6.

8. The membrane as described in claim 7, wherein, The thickness of the membrane ranges from 400 nm to 2500 nm.

9. The membrane as described in claim 7, wherein, The cerium (Ce) content of the film is greater than 4%.

10. A magnesium alloy substrate, characterized in that the surface of the magnesium alloy substrate has a film as described in any one of claims 7 to 9.

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