# US 8,540,826 B2 · Method of surface treatment of aluminum foil and its alloy and method of producing immobilized nanocatalyst of transition metal oxides and their alloys

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- Number: US 8,540,826 B2
- Document ID: US8540826B2
- Status: Granted
- Kind: B2
- Application number: 12/923,688
- Filed: 2010-10-04
- Published: 2011-11-24
- Granted: 2013-09-24
- Earliest claimed: 2009-10-02
- Assignees: University of Windsor
- Applicants: Srimanta Ray; Jerald A. D. Lalman
- Inventors: Srimanta Ray; Jerald A. D. Lalman
- Web page: https://patentgrep.com/patent/US8540826B2

## CPC

- C23F 1/20: for etching aluminium or alloys thereof
- B01J 21/063: {Titanium; Oxides or hydroxides thereof}
- B01J 35/58: Fabrics or filaments
- B01J 37/0018: {Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)}
- B01J 37/0225: {of metal substrates}
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- C23C 18/04: Pretreatment of the material to be coated (C23C18/06 takes precedence)
- C23C 18/1216: {Metal oxides (C23C18/1212 takes precedence)}
- C23C 18/1241: {Metallic substrates}
- C23C 18/1245: {Inorganic substrates other than metallic}
- C23C 18/125: {Process of deposition of the inorganic material}
- C23C 18/1295: {with after-treatment of the deposited inorganic material}
- C23F: NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K26/00; desurfacing by applying flames B23K7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C1/22; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

A process for surface treatment of aluminium foils includes steps of applying an etching solution to chemically etch at least one surface of the foil to form an etched surface, and forming an aluminium oxidized coating on the etched surface. The etching solution comprises an aqueous solution which includes hydrogen peroxide as an oxidant and sulfuric, orthophosphoric or nitric acid.

## Claims

### Claim 1

A process for a surface treatment of an aluminium foil comprising the steps of:
applying an etching solution to chemically etch at least one surface of said foil to form an etched surface, said etching solution comprising an aqueous solution including an oxidant and an acid selected from the group consisting of sulfuric acid, orthophosphoric acid and nitric acid, said acid being present in said solution in a concentration selected at from about 5.4 M to 9.4 M, and wherein said oxidant comprises hydrogen peroxide present in said solution in an amount of about 12 wt % to 18 wt %, and
forming an aluminium oxidized coating on said etched surface.

### Claim 2 (depends on 1)

The process of claim 1, wherein said acid is present in said solution in a concentration selected at about 7.5 +\−0.2 M.

### Claim 3 (depends on 1)

The process of claim 1 comprising simultaneously applying said etching solution to both surfaces of said foil as a single step treatment.

### Claim 4 (depends on 1)

The process of claim 1, wherein said etching solution is applied for a time selected to form said etched surface into said foil to a depth of between about 150 to 300 nm.

### Claim 5 (depends on 4)

The process of claim 4, wherein said etched surface comprises nano-pores having a mean pore diameter size selected at between about 100 to 300 nm.

### Claim 6 (depends on 1)

The process of claim 1, wherein said step of chemical etching is conducted at ambient temperature.

### Claim 7 (depends on 1)

The process of claim 1 including a step of applying a coating composition selected from a paint coating, a colour coating and an adhesion coating over said aluminium oxidized coating.