PROCESS TO MITIGATE SPALLATION OF ANODIC OXIDE COATINGS FROM HIGH STRENGTH SUBSTRATE ALLOYS

摘要

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.

主权项

1. A method of forming an anodic oxide coating on a substrate, the substrate including at least one alloying agent, the method comprising:
forming a cosmetic anodic oxide layer by anodizing the substrate in a first electrolyte; and forming an adhesion-promoting anodic oxide layer between the cosmetic anodic oxide layer and the substrate by anodizing the substrate in a second electrolyte different than the first electrolyte, wherein the second electrolyte is substantially free of sulfur or sulfur-containing species, wherein each of the cosmetic anodic oxide layer and the adhesion-promoting anodic oxide layer has a plurality of pores.