Apple Inc.
Titanium surfaces with improved color consistency and resistance to color change

Abstract:

This application relates to a method for forming an enclosure for a portable electronic device. The enclosure includes a metal substrate having a first b* value. The method includes forming an anodized layer that overlays and is formed from the metal substrate, wherein the anodized layer has a second b* value that is no greater than 0.3 of the first b* value and no less than 0.3 less than the first *b value.