An Apple patent (number 20110017602) for dual anodization surface treatment has appeared at the US Patent & Trademark Office. A metal surface treated to have two anodized layers or regions may be used in future electronic devices from Apple.
The surface treatment may include performing a first anodization process to create a first anodized layer, removing the first anodized layer at select locations, and performing a second anodization process to create a second anodized layer at the select locations. The first and second anodized regions may have different decorative properties, such as color, and different structural properties, such as degree of abrasion resistance. One of the anodization processes may be hard anodization and the other may be standard anodization. The inventor is Jivan K. Zhosla.
Here's Apple's background and summary of the invention: The present invention relates to treatments for a surface of an article and an article with a treated surface...| Read more »