Apple Inc.
Process for incorporating zinc into a dyed anodized layer for protecting dye colorants from light exposure

Abstract:

This application relates to a method for forming an enclosure for a portable electronic device, the enclosure including a metal substrate that is overlaid by an anodized layer. The method includes dyeing the anodized layer by exposing pores of the anodized layer to a dye. The method further includes sealing the dye within the pores by exposing the anodized layer to a zinc-based sealing solution, where an external surface of the anodized layer having the pores that are sealed includes an amount of zinc between about 3 wt % to about 6 wt %.