# US 11,299,815 B2 · Hierarchically structured duplex anodized aluminum alloy

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- Number: US 11,299,815 B2
- Document ID: US11299815B2
- Status: Granted
- Kind: B2
- Application number: 17/063,069
- Filed: 2020-10-05
- Published: 2021-02-11
- Granted: 2022-04-12
- Earliest claimed: 2014-10-13
- Assignees: Raytheon Technologies Corporation
- Applicants: Raytheon Technologies Corporation
- Inventors: Zhongfen (Vivian) Ding; Georgios S. Zafiris; Mark R. Jaworowski
- Web page: https://patentgrep.com/patent/US11299815B2

## CPC

- C25D 11/12: Anodising more than once, e.g. in different baths
- C25D 11/024: {Anodisation under pulsed or modulated current or potential}
- C25D 11/06: characterised by the electrolytes used
- C25D 11/08: containing inorganic acids
- C25D 11/10: containing organic acids
- C25D 11/246: {for sealing layers}
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR

## Abstract

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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

The hierarchically structured anodized film as recited in claim 1, wherein said stepped growth TSA film layer has a multiple of densities therein.

### Claim 3 (depends on 1)

The hierarchically structured anodized film as recited in claim 1, wherein said stepped growth TSA film layer has a multiple of porosities therein.

### Claim 4 (depends on 1)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

The hierarchically structured anodized film as recited in claim 1, wherein the concentration of the tartaric acid is 60-100 gram/L.

### Claim 7 (depends on 1)

The hierarchically structured anodized film as recited in claim 1, wherein said stepped growth TSA film layer is sealed.

### Claim 8 (depends on 1)

The hierarchically structured anodized film as recited in claim 1, wherein said stepped growth TSA film layer is sealed with a chromium compound.

### Claim 9 (depends on 1)

The hierarchically structured anodized film as recited in claim 1, wherein said stepped growth TSA film layer comprises alternating porosities therein.

### Claim 10 (depends on 1)

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.

### Claim 11 (depends on 1)

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.