Method for self-repairing of damage to inorganic protective layer on metal surface

Patent metadata

Field	Value
Publication number	US-2025084555-A1
Application number	US-202318522987-A
Country	US
Kind code	A1
Filing date	Nov 29, 2023
Priority date	Sep 7, 2023
Publication date	Mar 13, 2025
Grant date	—

Abstract

Disclosed is a method for self-repairing of damage to an inorganic protective layer on a metal surface. The method includes: placing a metal with the inorganic protective layer having a damaged surface in a chloride ion solution, and performing self-repairing, wherein the metal with the inorganic protective layer comprises a metal substrate and a layered double hydroxide protective layer intercalated by acid anions covering a surface of the metal substrate; and the acid anions are selected from the group consisting of phosphate anions and molybdate anions.

First claim

1 . A method for self-repairing of damage to an inorganic protective layer on a metal surface, comprising:
placing a metal with the inorganic protective layer having a damaged surface in a chloride ion solution, and performing self-repairing, wherein the metal with the inorganic protective layer comprises a metal substrate and a layered double hydroxide protective layer intercalated by acid anions covering a surface of the metal substrate; and the acid anions are selected from the group consisting of phosphate anions and molybdate anions.

2 . The method of claim 1 , wherein the metal substrate comprises one selected from the group consisting of steel material, zinc material, magnesium material, aluminum material, and copper material.

3 . The method of claim 1 , wherein the layered double hydroxide protective layer intercalated by acid anions has a thickness of less than or equal to 50 micrometers.

4 . The method of claim 1 , wherein the metal with the inorganic protective layer is prepared by a process comprising the following steps:
mixing a first divalent metal salt, aluminium nitrate and water to obtain a mixed solution; taking the mixed solution as a deposition solution, constructing a three-electrode system with a metal substrate as a working electrode, and performing electrodeposition with the three-electrode system to obtain a post-deposition metal substrate; mixing a second divalent metal salt, aluminium nitrate, an acid anion source and water to obtain a mixture, and adding ammonia water to the mixture to adjust a pH value thereof to 9-12 to obtain a hydrothermal reaction solution; and placing the post-deposition metal substrate in the hydrothermal reaction solution, and performing hydrothermal reaction to obtain the metal with the inorganic protective layer, wherein the first divalent metal salt and the second divalent metal salt are each independently selected from the group consisting of zinc nitrate and magnesium nitrate; and the acid anion source comprises one selected from the group consisting of a dihydrogen phosphate or a molybdate.

5 . The method of claim 1 , wherein the chloride ion solution comprises a sodium chloride solution; and the sodium chloride solution has a concentration of 3.5 wt %.

6 . The method of claim 1 , wherein the self-repairing is performed at room temperature.

7 . The method of claim 2 , wherein the metal with the inorganic protective layer is prepared by a process comprising the following steps:
mixing a first divalent metal salt, aluminium nitrate and water to obtain a mixed solution; taking the mixed solution as a deposition solution, constructing a three-electrode system with a metal substrate as a working electrode, and performing electrodeposition with the three-electrode system to obtain a post-deposition metal substrate; mixing a second divalent metal salt, aluminium nitrate, an acid anion source and water to obtain a mixture, and adding ammonia water to the mixture to adjust a pH value thereof to 9-12 to obtain a hydrothermal reaction solution; and placing the post-deposition metal substrate in the hydrothermal reaction solution, and performing hydrothermal reaction to obtain the metal with the inorganic protective layer, wherein the first divalent metal salt and the second divalent metal salt are each independently selected from the group consisting of zinc nitrate and magnesium nitrate; and the acid anion source comprises one selected from the group consisting of a dihydrogen phosphate or a molybdate.

8 . The method of claim 3 , wherein the metal with the inorganic protective layer is prepared by a process comprising the following steps:
mixing a first divalent metal salt, aluminium nitrate and water to obtain a mixed solution; taking the mixed solution as a deposition solution, constructing a three-electrode system with a metal substrate as a working electrode, and performing electrodeposition with the three-electrode system to obtain a post-deposition metal substrate; mixing a second divalent metal salt, aluminium nitrate, an acid anion source and water to obtain a mixture, and adding ammonia water to the mixture to adjust a pH value thereof to 9-12 to obtain a hydrothermal reaction solution; and placing the post-deposition metal substrate in the hydrothermal reaction solution, and performing hydrothermal reaction to obtain the metal with the inorganic protective layer, wherein the first divalent metal salt and the second divalent metal salt are each independently selected from the group consisting of zinc nitrate and magnesium nitrate; and the acid anion source comprises one selected from the group consisting of a dihydrogen phosphate or a molybdate.

Assignees

• Univ Shenzhen

Inventors

• Hong Shuxian
• Dong Biqin
• Xing Feng
• Zeng Lei
• Zhang Yuanyuan
• Liu Wenjie
• Yang Qingrui

Classifications

• C25D5/67 Primary

  Electroplating to repair workpiece · CPC title

• C25D9/04 Primary

  with inorganic materials · CPC title

• C25D5/36

  of iron or steel · CPC title

• C23C26/00 Primary

  Coating not provided for in groups C23C2/00 - C23C24/00 · CPC title