Hydration inhibitor coating for adhesive bonds

• US 8,574,396 B2
• Filed: 08/30/2010
• Issued: 11/05/2013
• Est. Priority Date: 08/30/2010
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Bhaatia, Promila P., Parkos, Joseph
• Primary Examiner(s): ORLANDO, MICHAEL N
• Application Number:
  US12/870,892
• Publication Number:
  US 20120052304A1
• Time in Patent Office: 1,163 Days
• Field of Search: 148/284, 156/281, 156/330, 428/414
• US Class Current: 156/330
• CPC Class Codes: B32B 3/12 characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B32B 9/041 of metal
• CPC Class Codes: C09J 2400/163 in the substrate
• CPC Class Codes: C09J 2400/166 in the pretreated surface to be joined
• CPC Class Codes: C09J 2463/00 Presence of epoxy resin
• CPC Class Codes: C09J 5/02 involving pretreatment of the surfaces to be joined
• CPC Class Codes: C23C 22/78 Pretreatment of the material to be coated
• CPC Class Codes: C23C 2222/10 Use of solutions containing trivalent chromium but free of hexavalent chromium
• CPC Class Codes: C25D 11/18 After-treatment, e.g. pore-sealing
• CPC Class Codes: C25D 11/24 Chemical after-treatment
• CPC Class Codes: Y10T 428/24149 Honeycomb-like
• CPC Class Codes: Y10T 428/31515 As intermediate layer
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

A method for adhesively bonding a metallic substrate and a component together includes treating the metallic substrate to form an oxide layer thereon, treating the oxide layer with a conversion coating solution to form a bond promoter coating on the oxide layer, and depositing an adhesive material on the bond promoter coating to bond the component and the metallic substrate together.

Claims

1. A method for adhesively bonding a metallic substrate and a component together, the method comprising:

treating the metallic substrate to form an oxide layer thereon;

treating the oxide layer with a conversion coating solution that includes phosphonic acid and trivalent chromium to form a phosphonate monolayer bond promoter coating on the oxide layer; and

depositing an adhesive material on the phosphonate monolayer bond promoter coating to bond the component and the metallic substrate together.

2. The method as recited in claim 1, wherein the treating of the metallic substrate includes anodizing.

3. The method as recited in claim 2, wherein the anodizing includes using a solution selected from a group consisting of sulfuric acid, phosphoric acid, organic acid, boric acid, chromic acid, and combinations thereof.

4. The method as recited in claim 1, wherein the conversion coating solution includes nitrilotris (methyelene) triphosphonic acid.

5. The method as recited in claim 1, wherein the adhesive material is epoxy.

11. The method as recited in claim 1, wherein the component is a honeycomb.

12. The method as recited in claim 11, wherein the metallic substrate is an aluminum alloy sheet.

6. A method for inhibiting hydration of an adhesive joint, the method comprising:

in an adhesively bonded article having a metallic substrate, an oxide layer on the metallic substrate, and an adhesive material joining a component and the metallic substrate together, resisting hydration of the oxide layer by using a phosphonate monolayer bond promoter coating as a barrier between the oxide layer and the adhesive material.

7. The method as recited in claim 6, including limiting diffusion movement of water from the adhesive material to the oxide layer using the bond promoter coating.

8. The method as recited in claim 6, wherein the bond promoter coating_is a phosphonate monolayer coating.

9. The method as recited in claim 8, wherein the phosphonate monolayer coating is a conversion coating.

10. The method as recited in claim 6, wherein the oxide layer is aluminum oxide, and the resisting of hydration of the oxide layer includes resisting conversion of the aluminum oxide into oxyhydroxide boehmite, bayerite, or combinations thereof.