Chromium-free conversion coating

Patent metadata

Field	Value
Publication number	US-9290846-B2
Application number	US-201514628756-A
Country	US
Kind code	B2
Filing date	Feb 23, 2015
Priority date	Mar 5, 2014
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

A conversion coating composition including a conducting polymer dispersion, at least one silane and inorganic metallic salts, wherein a pH of the composition is between 1.0 and 6.0, and wherein the inorganic metallic salts include at least one zirconium salt and at least one cerium nitrate salt.

First claim

What is claimed is:

1. A composition comprising a conducting polymer dispersion, at least one silane and inorganic metallic salts, wherein a pH of the composition is between 1.0 and 6.0, and wherein the inorganic metallic salts comprise at least one zirconium salt and at least one cerium nitrate salt.

2. The composition of claim 1 wherein the at least one zirconium salt is potassium hexafluorozirconate.

3. The composition of claim 1 wherein the at least one cerium nitrate salt is selected from the group consisting of cerium (III) nitrate, cerium (IV) ammonium nitrate and any combination thereof.

4. The composition of claim 1 wherein the at least one cerium nitrate salt is cerium (IV) ammonium nitrate.

5. The composition of claim 1 :
wherein the at least one zirconium salt is in a concentration of between 2.0 and 20 g/L, expressed in weight of Zr salts with respect to the total volume of the composition, and
wherein the at least one cerium nitrate salt is in a concentration of between 0.5 and 20 g/L, expressed in weight of Ce nitrate salts with respect to the total volume of the composition.

6. The composition of claim 1 wherein the pH is between 3.0 and 5.0.

7. The composition of claim 1 wherein the at least one silane is present in an amount of from about 0.01 v % (v/v) to about 1.0 v % (v/v) of the composition.

8. The composition of claim 1 wherein the at least one silane is of the formula:
YSiX (3-a) Z a

wherein
X are equal or different hydrolysable groups,
Y is non-hydrolysable group comprising a functional group,
Z are independently selected from H and alkyl, and
a is 0, 1 or 2.

9. The composition of claim 1 wherein the at least one silane comprises a member selected from the group consisting of (3-Glycidoxypropyl)trimethoxysilane (GPMS), 1,2-Bis(trimethoxysilyl)ethane (TMSE), 1,2-Bis(Triethoxysilyl)ethane (BTSE), Bis[3-(trimethoxysilyl)propyl]amine (BAS) and Vinyltriacetoxysilane (VTAS), and combinations thereof.

10. The composition of claim 1 wherein the conducting polymer dispersion comprises one conducting polymer selected from the group consisting of polyaniline, polyethylenedioxythiophene and polypyrrole.

11. A metallic surface contacted with the composition of claim 1 .

12. A process for treatment of a metallic surface, the process comprising steps of:
a) pretreating the metallic surface;
b) coating the metallic surface with a conversion coating by contacting such metallic surface with a composition, the composition comprising a conducting polymer dispersion, at least one silane and inorganic metallic salts, wherein a pH of the composition is between 1.0 and 6.0, and wherein the inorganic metallic salts comprise at least one zirconium salt and at least one cerium nitrate salt; and
c) drying the coated metallic surface.

13. The process of claim 12 wherein the coating is performed in a single-step, by immersion of the pretreated metallic surface into the composition for a period of time between 1 and 10 minutes and at a temperature between 15 and 30° C.

14. The process of claim 12 wherein the at least one zirconium salt is potassium hexafluorozirconate.

15. The process of claim 12 wherein the at least one cerium nitrate salt is selected from the group consisting of cerium (III) nitrate, cerium (IV) ammonium nitrate and any combination thereof.

16. The process of claim 12 wherein the at least one cerium nitrate salt is cerium (IV) ammonium nitrate.

17. The process of claim 12 :
wherein the at least one zirconium salt is in a concentration of between 2.0 and 20 g/L, expressed in weight of Zr salts with respect to the total volume of the composition, and
wherein the at least one cerium nitrate salt is in a concentration of between 0.5 and 20 g/L, expressed in weight of Ce nitrate salts with respect to the total volume of the composition.

18. The process of claim 12 wherein the pH is between 3.0 and 5.0.

19. The process of claim 12 wherein the at least one silane is present in an amount of from about 0.01 v % (v/v) to about 1.0 v % (v/v) of the composition.

20. The process of claim 12 wherein the at least one silane is of the formula:
YSiX (3-a) Z a

wherein
X are equal or different hydrolysable groups,
Y is non-hydrolysable group comprising a functional group,
Z are independently selected from H and alkyl, and
a is 0, 1 or 2.

Assignees

• Boeing Co

Inventors

• Rey Nieves Lapena
• Mozo Patricia Santa Coloma
• Etxeberria Usoa Izagirre
• Alcorta Oihana Zubillaga
• Cano Iranzo Francisco J

Classifications

• C23C22/361

  containing titanium, zirconium or hafnium compounds · CPC title

• C23C2222/20

  Use of solutions containing silanes · CPC title

• C09D165/00

  Coating compositions based on macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain (C09D107/00 - C09D157/00, C09D161/00 take precedence); Coating compositions based on derivatives of such polymers · CPC title

• C09D5/08

  Anti-corrosive paints · CPC title

• C23C22/34 Primary

  containing fluorides or complex fluorides · CPC title