Hierarchically structured duplex anodized aluminum alloy
A method of growing a hierarchically structured anodized film to an aluminum substrate including growing a Phosphoric Acid Anodizing (PAA) film layer to an aluminum substrate and growing a multiple of Tartaric-Sulfuric Acid Anodizing (TSA) film layers under the Phosphoric Acid Anodizing (PAA) film layer.
1. A hierarchically structured anodized film for an aluminum substrate, comprising:
a stepped growth Tartaric-Sulfuric Acid (TSA) film layer comprising a tartaric acid, a sulfuric acid and an aluminum oxide, wherein the stepped growth TSA film is a porous film comprising alternating TSA layers of a first layer having a first density and a second layer having a second density different from the first density; and
further comprising a phosphoric acid anodizing (PAA) film layer on said stepped growth TSA film layer, wherein said phosphoric acid anodizing (PAA) film layer is a porous oxide layer comprising phosphate and aluminum oxide.
2. The hierarchically structured anodized film as recited in claim 1 , wherein said stepped growth TSA film layer has a multiple of densities therein.
3. The hierarchically structured anodized film as recited in claim 1 , wherein said stepped growth TSA film layer has a multiple of porosities therein.
4. The hierarchically structured anodized film as recited in claim 1 , wherein said stepped growth TSA film layer is formed via a multiple of different repeating anodizing voltages.
5. The hierarchically structured anodized film as recited in claim 1 , wherein said stepped growth TSA film layer is thicker and denser than said PAA film layer.
6. The hierarchically structured anodized film as recited in claim 1 , wherein the concentration of the tartaric acid is 60-100 gram/L.
7. The hierarchically structured anodized film as recited in claim 1 , wherein said stepped growth TSA film layer is sealed.
8. The hierarchically structured anodized film as recited in claim 1 , wherein said stepped growth TSA film layer is sealed with a chromium compound.
9. The hierarchically structured anodized film as recited in claim 1 , wherein said stepped growth TSA film layer comprises alternating porosities therein.
10. The hierarchically structured anodized film as recited in claim 1 , wherein said stepped growth TSA film layer is located at a sharp corner of the aluminum substrate.
11. The hierarchically structured anodized film as recited in claim 1 , wherein said tartaric acid facilitates formation of the stepped growth TSA film layer, but does not dissolve the PAA film layer.