Method to create thin functional coatings on light alloys

Patent metadata

Field	Value
Publication number	US-10519562-B2
Application number	US-201715678256-A
Country	US
Kind code	B2
Filing date	Aug 16, 2017
Priority date	Aug 17, 2016
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

In example implementations, a method for producing a thin film coating is provided. The method includes pre-treating a substrate, placing the substrate in a bath comprising at least phosphoric acid and sulphuric acid to produce a thin anodized layer, rinsing the thin anodized layer in a solution, plating a surface of the thin anodized layer in an electro deposition bath following a plating current profile for a predetermined period, and increasing the plating current to the recommended bath plating current to produce the thin film coating having a desired initial coating thickness.

First claim

The invention claimed is:

1. A method for producing a coating, comprising:
pre-treating a substrate;
placing the substrate in a bath comprising at least phosphoric acid and sulphuric acid and anodizing the substrate to produce a thin anodized layer;
rinsing the thin anodized layer in a solution;
plating a surface of the thin anodized layer in a single electro deposition bath following a plating current profile for a predetermined period, wherein the plating current profile is selected as a percentage of a nominal plating current that is applied via a direct current or a pulsed direct current, wherein the plating current profile comprises ramping the plating current from 0 to between 0.1 amperes per square decimeter (A/dm 2 ) and 2.0 A/dm 2 for a first time period, then holding the plating current constant at a value between 0.1 A/dm 2 and 2.0 A/dm 2 for a second time period; and
increasing the plating current from the value between 0.1 A/dm 2 and 2.0 A/dm 2 to a recommended bath plating current to produce the coating having a desired initial coating thickness.

2. The method of claim 1 , wherein the substrate comprises aluminium.

3. The method of claim 1 , wherein the substrate comprises any one of titanium and magnesium.

4. The method of claim 1 , wherein the thin anodized layer has a thickness between approximately 2 microns and 10 microns.

5. The method of claim 1 , wherein the pre-treating comprises:
degreasing the substrate in an alkaline bath;
roughening the substrate in a solution; and
etching the substrate in a nitric acid solution.

6. The method of claim 1 , wherein the solution for the rinsing comprises a bath of between 0.5 milliliters per liter (mL/L) to 5 mL/L of hydrofluoric acid.

7. The method of claim 1 , wherein the rinsing the thin anodized layer minimizes interference on the coating to produce a uniform film.

8. The method of claim 1 , wherein the thin anodized layer is produced at room temperature and at a constant voltage.

9. The method of claim 8 , wherein the constant voltage is between 30 Volts (V) and 60V.

10. The method of claim 1 , wherein the percentage is selected based on a thickness of the thin anodized layer and a time sufficient to fill anodized pores of the surface that is plated.

11. The method of claim 1 , wherein the percentage is between 5% and 50% of the nominal plating current.

12. The method of claim 1 , wherein the plating current profile is obtained via a process comprising: holding the plating current constant at the value between 0.12 A/dm 2 and 2.0 A/dm 2 for the second time period that is sufficient to fill anodizing pores of the surface that is plated; and
increasing the plating current to the recommended bath plating current for a third period of time sufficient to provide a uniform coating over the thin anodized layer.

Assignees

• Hou Fengyan
• Wang Yuxin
• Hu Bo
• Goode Christopher William
• Dong Junzhe
• Auckland Uniservices Ltd

Inventors

• Hou Fengyan
• Wang Yuxin
• Hu Bo
• Goode Christopher William
• Dong Junzhe

Classifications

• C25D11/30

  of magnesium or alloys based thereon · CPC title

• C25D11/20 Primary

  Electrolytic after-treatment · CPC title

• C25D11/16

  Pretreatment {, e.g. desmutting} · CPC title

• C25D11/10

  containing organic acids · CPC title

• C25D11/08

  containing inorganic acids · CPC title