Porous oxide for improved titanium-polymer bonding
AssigneeApple Inc.
InventorsJames A. Curran, James A. Yurko, Todd S. Mintz
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Abstract
A chemical treatment process has been identified as a simple and effective means of improving the bonding of injection-molded polymer to titanium surfaces. This process forms an oxide layer on a titanium surface that includes a layered double hydroxide. The layered double hydroxide both raises the bond strength and minimizes air or water leakage. The process enables the use of titanium alloys with injection molded polymer structural bonds in strong, lightweight, and water-resistant enclosures for consumer electronics.
Claims11
A titanium-polymer interface, comprising:
- an oxide layer on a titanium surface and a polymer, wherein the titanium surface comprises an etched surface including a peak to valley roughness of greater than about 20 microns and a non-uniform microstructure including a plate having an angle from about 30° to about 70° relative to the titanium surface;
- wherein the oxide layer and the polymer form a titanium-polymer bond comprising a bond strength of about 28 MPa or greater.
A non-uniform porous oxide layer formed on a titanium surface, wherein the titanium surface comprises an etched surface including a peak to valley roughness of greater than about 20 microns, the porous oxide layer comprising a plate having an angle from about 30° to about 70° relative to the titanium surface, the plate about 10 to about 100 nm in length extending from the surface oxide layer to a terminal end of the plate.
Dependencies are inferred from the claim text.