Anodizing and duplex protection of aluminum copper alloys

• US 5,362,569 A
• Filed: 03/22/1993
• Issued: 11/08/1994
• Est. Priority Date: 03/22/1993
• Status: Expired due to Fees

• Current Assignee: Garson P. Shulman
• Original Assignee: Albert J. Bauman
• Inventors: Bauman, Albert J.
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Wong, Edna
• Application Number:
  US08/034,291
• Time in Patent Office: 596 Days
• Field of Search: 205/50, 205/317, 205/324, 205/213, 205/329, 205/330, 205/332, 205/201, 205/204, 205/229, 205/188, 148/248, 148/251, 148/252, 148/274, 148/275, 148/276, 148/277
• US Class Current: 428/472.2
• CPC Class Codes: C07D 249/18 Benzotriazoles
• CPC Class Codes: C25D 11/16 Pretreatment , e.g. desmutting
• CPC Class Codes: C25D 11/24 Chemical after-treatment

Abstract

Copper alloys of aluminum are afforded extended protection against surface corrosion by anodizing the aluminum surface to be protected, treating the surface with a heterocyclic aromatic azole treating agent having up to 16 carbon atoms before, during or after the anodizing step, and coating the treated surface after anodize with a fatty acid of 5 to 24 carbon atoms.

Claims

1. Method of protecting copper alloys of aluminum against surface corrosion, comprising anodizing the aluminum surface to be protected, treating said surface with a heterocyclic aromatic azole treating agent having up to 16 carbon atoms before, during or after the anodizing step, and coating said treated surface after the anodizing step with a fatty acid of 5 to 24 carbon atoms.

3. The method of claim 1, further comprising anodizing said aluminum surface to an anodize layer thickness of 0.2 to 0.6 mils.

5. The method of claim 1, further comprising treating said aluminum surface with an organic solution of said treating agent in advance of anodizing said surface.

6. The method of claim 1, further comprising selecting as said alloy a copper aluminum alloy containing from 0.2 to 7 per cent copper by weight, adding said treating agent to an anodizing bath, and anodizing said surface in said bath while simultaneously treating said surface with said treating agent.

7. The method of claim 1, further comprising treating said anodized surface with an organic solution of said treating agent after said anodizing step.

8. The method of claim 1, further comprising simultaneously treating said anodized surface with treating agent and coating said surface with said fatty acid.

9. The method of claim 1, further comprising forming a solution of both said treating agent and said fatty acid.

24. The product of claim 1.

2. Method of protecting copper alloys of aluminum of the 1000, 2000, or 7000 series against surface corrosion, comprising anodizing the aluminum surface to be protected, treating said surface with a heterocyclic aromatic azole treating agent having up to 16 carbon atoms before, during or after the anodizing step, and coating said treated surface after the anodizing step with a fatty acid of 5 to 24 carbon atoms.

4. Method of protecting copper alloys of aluminum against surface corrosion, comprising anodizing the aluminum surface to be protected, treating said surface with benzotriazole-5-carboxylic acid treating agent before, during or after the anodizing step, and coating said treated surface after the anodizing step with a fatty acid of 5 to 24 carbon atoms.

10. Method of protecting series 1000, 2000 and 7000 copper-containing alloys of aluminum against surface corrosion, comprising pretreating said surface with a 1 to 10% by weight solution in a hydroxylated solvent for a time sufficient to deposit a coating of a heterocyclic aromatic azole treating agent having up to 16 carbon atoms on said surface, and thereafter in sequence subjecting said coated surface to an anodizing bath and coating with a fatty acid having from 5 to 24 carbon atoms.

11. The method according to claim 10, further comprising immersing said surface in an alcohol solution of said treating agent for 1 to 10 minutes.

12. The method according to claim 11, further comprising selecting benzotriazole-5-carboxylic acid or 2-mercaptobenzothiazole as said treating agent.

13. The method according to claim 11, in which said treating agent is benzotriazole-5-carboxylic acid, and further comprising coating said surface with a 1-10% by weight solution of stearic acid in an alcohol after said anodizing.

14. The method according to claim 11, in which the immersion time of said surface in said treating agent solution is from 1 to 5 minutes.

25. The product of claim 10.

15. Method of protecting series 1000, 2000 and 7000 copper-containing alloys of aluminum against surface corrosion, comprising dissolving a heterocyclic aromatic azole treating agent having up to 16 carbon atoms in an anodizing bath, anodizing bath, anodizing said surface in said bath, and thereafter coating said surface with a fatty acid having from 5 to 24 carbon atoms.

16. The method according to claim 15, further comprising using said treating agent at less than 100 millimole concentrations.

17. The method according to claim 16, further comprising selecting benzotriazole-5-carboxylic acid or 2-mercaptobenzothiazole as said treating agent.

18. The method according to claim 17, in which said treating agent is benzotriazole-5-carboxylic acid, and further comprising coating said surface with a 1-10% by weight solution of stearic acid in an alcohol after said anodizing.

19. The method according to claim 18, in which the anodize layer thickness is between 0.2 and 0.6 mils.

23. The method according to claim 17, in which said treating agent is benzotriazole-5-carboxylic acid, and further comprising coating said surface with a 1-10% by weight solution of stearic acid in isopropyl alcohol after said anodizing.

26. The product of claim 15.

20. Method of protecting series 1000, 2000 and 7000 copper-containing alloys of aluminum against surface corrosion, comprising anodizing said surface and thereafter coating said anodized surface with a common hydroxylated solution of a heterocyclic aromatic azole treating agent having up to 16 carbon atoms and a fatty acid having from 5 to 24 carbon atoms.

21. The method according to claim 20, further comprising using solution concentrations of each of said treating agent and said fatty acid between 0.5 and 10% by weight to volume.

22. The method according to claim 20, further comprising selecting benzotriazole-5-carboxylic acid or 2-mercaptobenzothiazole as said treating agent.

27. The product of claim 20.