Abstract:
Anodizing processes for providing durable and defect-free anodic oxide films, well suited for anodizing highly reflective surfaces, are described. In some embodiments, the anodizing electrolyte has a sulfuric acid concentration substantially less than conventional type II anodizing. In some embodiments, the electrolyte includes a mixture of sulfuric acid and one or more organic acids. In further embodiments, sulfuric acid is a relatively minor additive to an organic acid, primarily serving to minimize discoloration. The processes enables porous, optically clear, and colorless anodic films to be grown in a manner similar to conventional Type II sulfuric acid anodizing, but at lower current densities and/or higher temperatures, without compromising film surface hardness. The thickness uniformity of the resulting anodic oxide films can be within 5% between grains of {111}, {110} and {100} surface orientations. Furthermore, the anodic oxide films have minimal incorporated sulfates, thereby avoiding certain cosmetic and structural defects.
Abstract:
Anodic oxide coatings and methods for forming anodic oxide coatings are disclosed. In some embodiments, the anodic oxide coatings are multilayered coatings that include at least two anodic oxide layers formed using two separate anodizing processes. The anodic oxide coating includes at least an adhesion-promoting or color-controlling anodic oxide layer adjacent the substrate. The adhesion-promoting anodic oxide layer is formed using an anodizing process that involves using an electrolyte that prevents formation of delaminating compounds at an interface between the adhesion-promoting anodic oxide layer and the substrate, thereby securing the anodic oxide coating to the substrate. In some cases, the electrolyte includes an organic acid, such as oxalic acid. The anodic oxide coating can also include a cosmetic anodic oxide layer having an exposed surface corresponding to an external surface of the anodic oxide coating. Cosmetic anodic oxide layers can be designed to have a desired appearance or tactile quality.
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.
Abstract:
This application relates to an anodized part. The anodized part includes a metal substrate and an anodized layer overlaying and formed from the metal substrate. The anodized layer includes (i) an external surface that includes randomly distributed light-absorbing features that are capable of absorbing visible light incident upon the external surface, and (ii) pores defined by pore walls, where color particles are infused within the pores. The anodized layer is characterized as having a color having an L* value using a CIE L*a*b* color space that is less than 10.
Abstract:
A component for an electronic device can include a part including a first metal and a second metal diffusion bonded to the first metal. The first metal can be aluminum and the second metal can be different from the first metal. A porous aluminum oxide layer can overlie a portion of the first metal and can be disposed adjacent to an interface between the first metal and the second metal. The component can further include a non-metallic material bonded to the part and extending into pores defined by the porous aluminum oxide layer.
Abstract:
This application relates to an enclosure for a portable electronic device. The enclosure includes a metal substrate and a dehydrated anodized layer overlaying the metal substrate. The dehydrated anodized layer includes pores having openings that extend from an external surface of the dehydrated anodized layer and towards the metal substrate, and a metal oxide material that plugs the openings of the pores, where a concentration of the metal oxide material is between about 3 wt % to about 10 wt %.
Abstract:
This application relates to an enclosure for a portable electronic device. The enclosure includes an aluminum alloy substrate and an anodized layer overlaying and formed from the aluminum alloy substrate, wherein the anodized layer has an external surface that has a concentration of zinc that is between about 3 wt % to about 7 wt %.
Abstract:
Anodic oxide coatings and methods for forming anodic oxide coatings on metal alloy substrates are disclosed. Methods involve post-anodizing processes that improve the appearance of the anodic oxide coating or increase the strength of the underlying metal alloy substrates. In some embodiments, a diffusion promoting process is used to promote diffusion of one or more types of alloying elements enriched at an interface between the anodic oxide coating and the metal alloy substrate away from the interface. The diffusion promoting process can increase an adhesion strength of the anodic oxide film to the metal alloy substrate and reduce an amount of discoloration due to the enriched alloying elements. In some embodiments, a post-anodizing age hardening process is used to increase the strength of the metal alloy substrate and to improve cosmetics of the anodic oxide coatings.
Abstract:
The embodiments described herein relate to treatments for anodic layers. The methods described can be used to impart a white appearance for an anodized substrate. The anodized substrate can include a metal substrate and a porous anodic layer derived from the metal substrate. The porous anodic layer can include pores defined by pore walls and fissures formed within the pore walls. The fissures can act as a light scattering medium to diffusely reflect visible light. In some embodiments, the method can include forming fissures within the pore walls of the porous anodic layer. In some embodiments, exposing the porous anodic layer to an etching solution can form fissures. The method further includes removing a top portion of the porous anodic layer while retaining a portion of the porous anodic layer.
Abstract:
Processes for enhancing the corrosion resistance of anodized substrates are disclosed. In some embodiments, the process involves a second anodizing operation that targets an area of the substrate that is left inadequately protected by a first anodizing operation, and also targets defects that may have been arisen from intermediate processing operations such as laser-marking operations. The second anodizing operation can be conducted in a non-pore-forming electrolyte, and grows a thick protective barrier film over inadequately protected areas of the substrate, such as laser-marking treated areas.