# US 2025/0146162 A1 · Development of water-repellent stainless steel (sus 316l) surface by stepwise anodizing technique

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- Number: US 2025/0146162 A1
- Document ID: US20250146162A1
- Status: Published application
- Kind: A1
- Application number: 18/386,787
- Filed: 2023-11-03
- Published: 2025-05-08
- Earliest claimed: 2023-11-03
- Assignees: Dong-Eui University Industrial-Academic Cooperation Foundation
- Applicants: Dong-Eui University Industrial-Academic Cooperation Foundation
- Inventors: Chanyoung JEONG
- Web page: https://patentgrep.com/patent/US20250146162A1

## CPC

- C25D 11/34: of metals or alloys not provided for in groups C25D11/04 - C25D11/32
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR

## Abstract

The present disclosure relates to a technology for developing a water-repellent stainless steel (SUS 316L) surface for improving a corrosion inhibition (corrosion resistance) efficiency. According to the method for forming a hydrophobic and corrosion resistant oxide film on a stainless steel surface according to the present disclosure, uniform porous oxide film may be formed without a pre-patterning process for forming uniform porous oxide films of the related art to achieve excellent hydrophobicity and corrosion resistance, thereby being applied to medical devices, marine transportation vehicles, land transportation vehicles, air transportation vehicles, water and sewage pipes, water and sewage filters, and the like, including stainless steel and also be useful as a machine learning database for developing stainless steel surface treatment technology.

## Claims

### Claim 1

A method for forming a hydrophobic and corrosion resistant oxide film on a stainless steel surface, comprising:
washing and drying the stainless steel surface (Step 1);
anodizing at an applied voltage of 80 to 100 V for 2.5 to 3.5 hours to form an anodized film on the stainless steel surface (Step 2);
immersing the anodized stainless steel of Step 2 into 0.05 to 1.0 M a phosphoric acid solution to widen pores (Step 3);
conducting plasma treatment to remove organic residues and making the anodized film surface hydrophilic (Step 4); and
coating with a self-assembled monolayer (SAM) coatable hydrophobic coating agent (Step 5).

### Claim 2 (depends on 1)

The method of claim 1, wherein the stainless steel is SUS 316 or SUS 316L.

### Claim 3 (depends on 1)

The method of claim 1, wherein during the anodizing of Step 2, a mixture of NH4F, water, and ethylene glycol is used as an electrolyte.

### Claim 4 (depends on 1)

The method of claim 1, wherein the anodizing of Step 2 is performed at an applied voltage of 85 to 95 V for 2.8 to 3.2 hours.

### Claim 5 (depends on 4)

The method of claim 4, wherein the anodizing of Step 2 is performed at an applied voltage of 88 to 92 V for 2.9 to 3.1 hours.

### Claim 6 (depends on 1)

The method of claim 1, wherein the SAM coatable hydrophobic coating agent is any one selected from the group consisting of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS), trichloroctylsilane (OTS), and octadecyltrichlorosilane (ODTS).

### Claim 7 (depends on 1)

The method of claim 1, wherein the anodized film with a contact angle of 160° or larger is formed on the stainless steel surface.

### Claim 8 (depends on 1)

The method of claim 1, wherein the anodized film with a corrosion inhibition efficiency of 90% or higher is formed on the stainless steel surface.

### Claim 9 (depends on 1)

A stainless steel in which a hydrophobic anodized film manufactured by the method of claim 1 is formed.

### Claim 10 (depends on 1)

A stainless steel in which a corrosion resistant anodized film manufactured by the method of claim 1 is formed.

### Claim 11 (depends on 1)

A medical device including a stainless steel manufactured by the method of claim 1.

### Claim 12 (depends on 1)

A transportation vehicle including a stainless steel manufactured by the method of claim 1.

### Claim 13 (depends on 12)

The transportation vehicle of claim 12, wherein the transportation vehicle is a marine transportation vehicle, a land transportation vehicle, or an air transportation vehicle.

### Claim 14 (depends on 1)

A water and sewage pipe including the stainless steel manufactured by the method of claim 1.

### Claim 15 (depends on 1)

A water and sewage filter including the stainless steel manufactured by the method of claim 1.