Apple Inc.
Electronic Devices With Corrosion-Resistant Colored Metal Structures

Abstract:

An electronic device may have a housing. The device may include metal structures such as a metal member forming a portion of the housing, a portion of a strap, or other portions of the device. A gold-containing coating such as a layer of elemental gold or a gold alloy may cover the metal member to provide the metal member with a gold appearance or other desired appearance. To protect the metal member and the gold-containing coating, the metal member and gold-containing coating may be covered with a protective coating layer such as an organic protective layer. The organic protective layer may have a fluoropolymer layer with thiol coupling groups to promote adhesion to the gold-containing layer or may contain a polymer layer with silane and thiol coupling groups that serves as an adhesion promotion layer for an overlapping fluoropolymer layer with silane coupling groups.