Direct electrochemical synthesis of doped conductive polymers on metal alloys

Patent metadata

Field	Value
Publication number	US-10557210-B2
Application number	US-201414188259-A
Country	US
Kind code	B2
Filing date	Feb 24, 2014
Priority date	Feb 24, 2014
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

This disclosure relates generally to the discovery of improved methods of reducing corrosion on metals and metal alloys without using hexavalent chromium reagents. More particularly, the disclosure relates to preparing corrosion resistant metals using doped conducting polymers such as polyaniline (PANI) on metal alloys such as aluminum alloys.

First claim

What is claimed is:

1. A method for preparing a corrosion-resistant anodized metal surface, the method comprising:
anodizing a metal surface with a bath liquid comprising water, sulfuric acid, and an aniline-monomer to form a corrosion-resistant coating of a doped polyaniline (PANI) on the metal surface;
de-doping the doped PANT of the anodized metal surface by rinsing the anodized metal surface with deionized (DI) water such that the corrosion-resistant coating of the doped PANI becomes de-doped and non-conducting; and
re-doping the de-doped PANI of the rinsed anodized metal surface by sealing the rinsed anodized metal surface with a seal solution consisting essentially of water and a dimercaptothiadiazole inhibitor at a temperature of about 80° C. to about 100° C. so as to form a re-doped conductive corrosion-resistant PANI coating on the rinsed anodized metal surface, wherein the dimercaptothiadiazole inhibitor is used as a dopant to form the re-doped conductive corrosion-resistant PANI coating.

2. The method of claim 1 , wherein the metal surface comprises an aluminum or an aluminum alloy.

3. The method of claim 2 , wherein the aluminum or aluminum alloy metal is an aluminum clad aluminum alloy.

4. The method of claim 1 , wherein the metal surface comprises a titanium or a titanium alloy.

5. The method of claim 1 , wherein the aniline-monomer is aniline.

6. The method of claim 1 , wherein the bath liquid is saturated.

7. The method of claim 1 , wherein the dimercaptothiadiazole inhibitor is in the seal solution at a concentration of about 0.01M and about 0.1M.

8. The method of claim 1 , wherein the seal solution has a temperature of about 2090° C. to about 100° C.

9. The method of claim 1 , further comprising testing to validate the corrosion-resistant anodized metal surface.

10. The method of claim 1 , wherein the metal surface is anodized in a bath to form the corrosion-resistant coating, the bath having a temperature of about 18° C. to about 26° C. and consisting essentially of the water, the sulfuric acid, and the aniline-monomer.

11. The method of claim 10 , wherein the anodized metal surface is rinsed while still wet from the bath, and wherein the seal solution is saturated.

12. The method of claim 11 , wherein the de-doped PANI is re-doped while still wet from the rinsing.

13. A method for making a doped polyaniline on a metal surface comprising:
electrochemically depositing an aniline-monomer on a metal surface to form a corrosion-resistant coating of a doped polyaniline (PANI) on the metal surface using a bath liquid comprising water, sulfuric acid, and the aniline-monomer;
de-doping the doped PANI by rinsing the coated metal surface with deionized (DI) water such that the corrosion-resistant coating of the doped PANI becomes de-doped and non-conducting; and
re-doping the rinsed metal surface by exposing the de-doped PANI on the rinsed metal surface to a dimercaptothiadiazole inhibitor so as to form a re-doped conductive corrosion-resistant PANI coating on the rinsed metal surface by sealing the rinsed metal surface with a seal solution consisting essentially of water and the dimercaptothiadiazole inhibitor at a temperature of about 80° C. to about 100° C., wherein the dimercaptothiadiazole inhibitor is used as a dopant to form the re-doped conductive corrosion-resistant PANI coating.

14. The method of claim 13 , wherein the metal surface comprises an aluminum or an aluminum alloy.

15. The method of claim 14 , wherein the aluminum or aluminum alloy metal is an aluminum clad aluminum alloy.

16. The method of claim 13 , wherein the metal surface comprises a titanium or a titanium alloy.

17. The method of claim 13 , wherein the aniline-monomer is aniline.

18. The method of claim 13 , wherein the seal solution is saturated with the dimercaptothiadiazole inhibitor.

19. The method of claim 13 , further comprising measuring a resistance associated with the sealed metal surface.

20. The method of claim 13 , wherein the re-doping is performed at a temperature of about 90° C. to about 100° C.

Assignees

• Boeing Co

Inventors

• Kinlen Patrick John
• Lawless Lawrence Michael

Classifications

• C25D11/26

  of refractory metals or alloys based thereon · CPC title

• C09D5/44

  for electrophoretic applications (processes for coating by electrophoresis C25D13/00) · CPC title

• C08K5/40

  Thiurams, {i.e. compounds containing[IMAGE cpc-sch-C08K-1011.gif] groups} · CPC title

• C25D11/246 Primary

  for sealing layers · CPC title

• C25D11/04

  of aluminium or alloys based thereon · CPC title