# US 2023/0407487 A1 · Etchant and method of surface treatment of aluminum or aluminum alloy

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- Number: US 2023/0407487 A1
- Document ID: US20230407487A1
- Status: Published application
- Kind: A1
- Application number: 18/336,944
- Filed: 2023-06-16
- Published: 2023-12-21
- Earliest claimed: 2022-06-16
- Assignees: C.Uyemura & Co., Ltd.
- Applicants: C.Uyemura & Co., Ltd.
- Inventors: Takuma Maekawa; Katsuhisa Tanabe; Sayuri Tanaka; Fuminori Shibayama
- Web page: https://patentgrep.com/patent/US20230407487A1

## CPC

- C23F 1/20: for etching aluminium or alloys thereof
- C23C 18/1651: {Two or more layers only obtained by electroless plating}
- C23C 18/1653: {Two or more layers with at least one layer obtained by electroless plating and one layer obtained by electroplating}
- C23C 18/1831: {Use of metal, e.g. activation, sensitisation with noble metals}
- C23C 18/32: Coating with nickel, cobalt or mixtures thereof with phosphorus or boron (C23C18/50 takes precedence)
- C23C 18/36: using hypophosphites
- C23C 18/54: Contact plating, i.e. electroless electrochemical plating
- C23G 1/125: {aluminium}
- C25D 5/44: Aluminium
- C23C 18/42: Coating with noble metals
- 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
- 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)
- C23G: CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR

## Abstract

The present invention aims to provide an etchant that can provide good deposition of a metal plating such as a nickel plating, despite its acidity, and a method of surface treatment of aluminum or an aluminum alloy using the etchant. Included is an etchant containing a zinc compound and a fluorine compound and having a pH of 4.5 to 6.5.

## Claims

### Claim 1

An etchant, comprising
at least one zinc compound and
at least one fluorine compound,
the etchant having a pH of 4.5 to 6.5.

### Claim 2 (depends on 1)

The etchant according to claim 1,
wherein the etchant comprises the zinc compound in an amount corresponding to a zinc concentration of 1.0 to 10 g/L.

### Claim 3 (depends on 1)

The etchant according to claim 1,
wherein the etchant comprises the fluorine compound in an amount corresponding to a fluorine concentration of 1.0 to 20.5 g/L.

### Claim 4 (depends on 1)

The etchant according to claim 1,
wherein the etchant is for treating aluminum or an aluminum alloy.

### Claim 5 (depends on 1)

A method of surface treatment of aluminum or an aluminum alloy, the method comprising a treatment including: bringing a workpiece having aluminum or an aluminum alloy on its surface into contact with the etchant according to claim 1 for etching; and pickling the etched workpiece.

### Claim 6 (depends on 5)

The method of surface treatment of aluminum or an aluminum alloy according to claim 5,
wherein the treatment is repeated at least twice.

### Claim 7 (depends on 6)

The method of surface treatment of aluminum or an aluminum alloy according to claim 6,
wherein the etchant used in each repetition of the treatment has the same composition.

### Claim 8 (depends on 5)

The method of surface treatment of aluminum or an aluminum alloy according to claim 5,
wherein the method comprises zinc displacement after the treatment.

### Claim 9 (depends on 6)

The method of surface treatment of aluminum or an aluminum alloy according to claim 6,
wherein the method comprises zinc displacement after the treatment.

### Claim 10 (depends on 8)

The method of surface treatment of aluminum or an aluminum alloy according to claim 8,
wherein the method comprises forming a metal plating film after the zinc displacement.

### Claim 11 (depends on 9)

The method of surface treatment of aluminum or an aluminum alloy according to claim 9,
wherein the method comprises forming a metal plating film after the zinc displacement.