Anodized aluminum alloy products having improved appearance and/or abrasion resistance, and methods of making the same

• US 10,087,542 B2
• Filed: 03/15/2013
• Issued: 10/02/2018
• Est. Priority Date: 09/24/2012
• Status: Active Grant

• Current Assignee: Arconic Technologies LLC (Arconic Corp.)
• Original Assignee: Arconic Inc. (Howmet Aerospace, Inc.)
• Inventors: Askin, Albert, Giocondi, Jennifer L., Denardo, Nicholas M., Brandon, Samantha M., Serafin, Daniel L.
• Primary Examiner(s): Cohen, Brian W
• Application Number:
  US13/834,805
• Publication Number:
  US 20140083861A1
• Time in Patent Office: 2,027 Days
• Field of Search: 205171, 205174, 205324, 205202
• CPC Class Codes: C25D 11/04 of aluminium or alloys based thereon
• CPC Class Codes: C25D 11/24 Chemical after-treatment
• CPC Class Codes: C25D 11/246 for sealing layers

Abstract

New methods of producing anodized aluminum alloy products having an improved surface appearance properties are disclosed. The methods may include preparing an aluminum alloy body for anodizing, thereby producing an anodized aluminum alloy body, contacting an intended viewing surface of the anodized aluminum alloy body with an acid, thereby producing a prepared intended viewing surface of the anodized aluminum alloy body, and sealing the prepared intended viewing surface of the anodized aluminum alloy body. The anodized aluminum alloy products may realize a preselected color tolerance, such as realizing a b* value that is within a specified tolerance of a preselected b* value.

Claims

1. A method comprising:

(a) preparing an aluminum alloy body for anodizing, wherein the aluminum alloy is a 2xxx, a 5xxx, a 6xxx, or a 7xxx aluminum alloy;

(b) anodizing the aluminum alloy body, thereby producing an anodized aluminum alloy body having an anodic oxide zone;

(i) wherein the anodizing is selected from the group consisting of type II anodizing, type III anodizing, and combinations thereof;

(c) contacting an intended viewing surface of the anodized aluminum alloy body with an acid to decrease the yellowness of the anodized aluminum alloy body, thereby producing a prepared intended viewing surface of the anodized aluminum alloy body;

(i) wherein the acid is selected from the group consisting of nitric acid, phosphoric acid, acetic acid, sulfuric acid, and mixtures thereof;

(ii) wherein the contacting occurs for a time of from 1 minute to 60 minutes;

(iii) wherein the contacting occurs at a temperature of from 40°

F. to 110°

F.;

(iv) wherein, when the acid is the nitric acid, the concentration of the nitric acid is from 0.67 wt. % to 67 wt. %; and

(d) sealing, via a sealing solution, the prepared intended viewing surface of the anodized aluminum alloy body, wherein the sealing solution is free of colorants, and wherein the method excludes coloring of the anodic oxide zone via dyes;

wherein the method comprises pre-selecting an abrasion resistance tolerance for the intended viewing surface of the aluminum alloy body; and

wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves the pre-selected abrasion resistance tolerance.

2. The method of claim 1, comprising:

determining a preselected color tolerance of the intended viewing surface of the aluminum alloy body;

wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves the preselected color tolerance.

10. The method of claim 1, wherein, after the anodizing step (b) and before the contacting step (c), the intended viewing surface of the anodized aluminum alloy body has an anodic oxide zone thickness of from 0.07 to 4.5 mil.

11. The method of claim 10, wherein the anodic oxide zone thickness is a pre-contacting anodic oxide zone thickness, wherein the method comprises:

completing the contacting step so as to achieve a final anodic oxide zone thickness that is within 10% of the pre-contacting anodic oxide zone thickness.

12. The method of claim 11, wherein the final anodic oxide zone thickness is within 5% of the pre-contacting anodic oxide zone thickness.

13. The method of claim 11, wherein the final anodic oxide zone thickness is within 3% of the pre-contacting anodic oxide zone thickness.

14. The method of claim 11, wherein the final anodic oxide zone thickness is within 1% of the pre-contacting anodic oxide zone thickness.

15. The method of claim 1, wherein the aluminum alloy has a longitudinal (L) tensile yield strength of at least 275 MPa.

16. The method of claim 15, wherein the aluminum alloy is a 7xxx aluminum alloy.

17. The method of claim 16, wherein the 7xxx aluminum alloy is one of a 7x75, 7x50, 7x55, or 7x85 aluminum alloy.

18. The method of claim 1, wherein the method consists of the stated steps.

19. The method of claim 2, wherein the method consists of the stated steps.

32. The method of claim 1, wherein the contacting occurs for at least 3 minutes.

33. The method of claim 1, wherein the anodic oxide zone comprises particles therein, and wherein the contacting step comprises removing at least some of the particles contained within the anodic oxide zone via the acid.

34. The method of claim 33, wherein the contacting step comprises enlarging pores of the anodic oxide zone.

3. A method comprising:

(a) preparing an aluminum alloy body for anodizing, wherein the aluminum alloy is a 2xxx, a 5xxx, a 6xxx, or a 7xxx aluminum alloy;

(b) anodizing the aluminum alloy body, thereby producing an anodized aluminum alloy body having an anodic oxide zone;

(i) wherein the anodizing is selected from the group consisting of type II anodizing, type III anodizing, and combinations thereof;

(c) determining a preselected color tolerance of an intended viewing surface of the aluminum alloy body;

(i) wherein the preselected color tolerance comprises a target b* value;

(d) contacting the intended viewing surface of the anodized aluminum alloy body with an acid to decrease the yellowness of the anodized aluminum alloy body, thereby producing a prepared intended viewing surface of the anodized aluminum alloy body;

(i) wherein the acid is selected from the group consisting of nitric acid, phosphoric acid, acetic acid, sulfuric acid, and mixtures thereof;

(ii) wherein the contacting occurs for a time of from 1 minute to 60 minutes;

(iii) wherein the contacting occurs at a temperature of from 40°

F. to 110°

F.;

(iv) wherein, when the acid is the nitric acid, the concentration of the nitric acid is from 0.67 wt. % to 67 wt. %;

(v) wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves the preselected color tolerance;

(vi) wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 1.0 units of the target b* value; and

(e) sealing, via a sealing solution, the prepared intended viewing surface of the anodized aluminum alloy body, wherein the sealing solution is free of colorants, and wherein the method excludes coloring of the anodic oxide zone via dyes.

4. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.5 unit of the target b* value.

5. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.4 unit of the target b* value.

6. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.3 unit of the target b* value.

7. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.2 unit of the target b* value.

8. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.1 unit of the target b* value.

9. The method of claim 3, wherein the actual b* value is lower than a b* value of a reference-version of the intended viewing surface of the aluminum alloy body in the anodized and then sealed condition.

20. A method comprising:

(a) determining a preselected color tolerance of an intended viewing surface of an aluminum alloy body, wherein the aluminum alloy is a 2xxx, a 5xxx, a 6xxx, or a 7xxx aluminum alloy;

(b) preparing the aluminum alloy body for anodizing;

(c) anodizing the aluminum alloy body, thereby producing an anodized aluminum alloy body having an anodic oxide zone;

(i) wherein the anodizing is selected from the group consisting of type II anodizing, type III anodizing, and combinations thereof;

(d) contacting an intended viewing surface of the anodized aluminum alloy body with an acid to decrease the yellowness of the aluminum alloy body, thereby producing a prepared intended viewing surface of the anodized aluminum alloy body, wherein the acid is selected from the group consisting of nitric acid, phosphoric acid, acetic acid, sulfuric acid, and mixtures thereof, and wherein the contacting occurs for a time of from 1 minute to 60 minutes;

(e) sealing, via a sealing solution, the prepared intended viewing surface of the anodized aluminum alloy body;

wherein the sealing solution is free of colorants;

wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves the preselected color tolerance;

wherein the preselected color tolerance comprises a target b* value, and wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 1.0 units of the target b* value; and

wherein the method excludes coloring of the anodic oxide zone via dyes.

21. The method of claim 20, wherein the acid is nitric acid.

22. The method of claim 21, wherein the nitric acid has a concentration of from 0.67% to 67%.

23. The method of claim 21, wherein the nitric acid has a concentration of from 0.67% to 33%.

24. The method of claim 21, wherein the nitric acid has a concentration of from 0.67% to 13.4%.

25. The method of claim 21, wherein the nitric acid has a concentration of from 0.67% to 6.7%.

26. The method of claim 22, wherein the contacting step (d) comprises immersing the anodized aluminum alloy body in a nitric acid bath comprising the nitric acid, wherein the nitric acid bath has a temperature of from 40°

to 110°

F.

27. The method of claim 26, wherein the nitric acid bath has a temperature of from 60°

to 100°

F.

28. The method of claim 26, wherein the nitric acid bath has a temperature of from 60°

to 95°

F.

29. The method of claim 26, wherein the nitric acid bath has a temperature of from 70°

to 90°

F.

30. The method of claim 26, wherein the aluminum alloy body is a 7xxx aluminum alloy.

31. The method of claim 30, wherein the 7xxx aluminum alloy is one of a 7x75, 7x50, 7x55, or 7x85 aluminum alloy.

35. The method of claim 20, wherein the contacting occurs for at least 3 minutes.

36. The method of claim 20, wherein the anodic oxide zone comprises particles therein, and wherein the contacting step comprises removing at least some of the particles contained within the anodic oxide zone via the acid.

37. The method of claim 36, wherein the contacting step comprises enlarging pores of the anodic oxide zone.