US 12,134,828 B2
Mixed acid anodization
Lei Chen, South Windsor, CT (US); and Mimi Nguyen-Vu, Berlin, CT (US)
Assigned to RTX CORPORATION, Farmington, CT (US)
Filed by RTX Corporation, Farmington, CT (US)
Filed on Nov. 13, 2020, as Appl. No. 17/097,614.
Prior Publication US 2022/0154361 A1, May 19, 2022
Int. Cl. C25D 11/08 (2006.01); C09D 5/44 (2006.01); C25D 5/44 (2006.01)
CPC C25D 11/08 (2013.01) [C09D 5/4484 (2013.01)] 5 Claims
 
1. A method of making an anodized metal component comprising:
anodizing a metal component in an anodizing bath to form an anodization layer;
wherein the anodizing bath comprises two or more inorganic acids selected from the group consisting of sulfuric, boric and phosphoric acids, and
an organic acid selected from the group consisting of oxalic acid, acetic acid, tartaric acid, malic acid, tannic acid, an α-amino acid, an aromatic alpha hydroxy acid, phenylalanine, and salicylic acid;
wherein anodizing is performed by applying a DC voltage ramped up from 0 to a plateau voltage over a period of 1 to 5 minutes, the plateau voltage varying from 13 to 20 volts and is maintained for a duration of 10 to 25 minutes;
wherein the anodizing bath comprises 10 g/L to 60 g/L of sulfuric acid and 80 g/L to 100 g/L of organic acid.