# US 12,110,419 B2 · Method of making silver-silicalite coated substrate

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- Number: US 12,110,419 B2
- Document ID: US12110419B2
- Status: Granted
- Kind: B2
- Application number: 17/962,071
- Filed: 2022-10-07
- Published: 2024-04-11
- Granted: 2024-10-08
- Earliest claimed: 2022-10-07
- Assignees: Imam Abdulrahman Bin Faisal University
- Applicants: Imam Abdulrahman Bin Faisal University
- Inventors: B. Rabindran Jermy; Vijaya Ravinayagam
- Web page: https://patentgrep.com/patent/US12110419B2

## CPC

- C09D 7/67: {Particle size smaller than 100 nm}
- C09D 1/00: Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
- C09D 5/084: {Inorganic compounds}
- C09D 5/14: Paints containing biocides, e.g. fungicides, insecticides or pesticides (C09D5/16 takes precedence)
- C09D 7/61: inorganic
- C09D 7/63: organic
- C09D 7/68: {Particle size between 100-1000 nm}
- C09D 171/02: Polyalkylene oxides
- C23C 18/1212: {Zeolites, glasses}
- C23C 18/1241: {Metallic substrates}
- C23C 18/127: {Preformed particles}
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- 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 method of making a silver-silicalite coating on a surface of a stainless-steel substrate is provided. The method includes mixing metakaolin with an aqueous solution of NaOH to form a first mixture. The method further includes mixing silica gel and silver nitrate with the first mixture to form a second mixture. Furthermore, the method includes mixing Zeolites Socony Mobil-5 (ZSM-5) with the second mixture to form a third mixture. The method further includes hydrothermally treating the stainless-steel substrate with the third mixture to form the silver-silicalite coating on the surface of the stainless-steel substrate. The hydrothermal treatment is carried out in the absence of an organic template. The stainless-steel substrate coated with the silver-silicalite coating, prepared by the method of the present disclosure, has lower corrosion in comparison to the same stainless-steel substrate without the silver-silicalite coating.

## Claims

### Claim 1

A method of making a silver-silicalite coating on a surface of a stainless-steel substrate, comprising:
mixing metakaolin with an aqueous solution of NaOH to form a first mixture;
mixing silica gel and silver nitrate with the first mixture to form a second mixture;
mixing ZSM-5 zeolite with the second mixture to form a third mixture; and
hydrothermally treating the stainless-steel substrate with the third mixture to form the silver-silicalite coating on the surface of the stainless-steel substrate,
wherein the silver-silicalite coating comprises rhombohedral cuboidal particles having an average length of 2 to 5 μm, an average width of 1 to 2 μm and an average height of 0.5 to 2 μm,
wherein the hydrothermal treatment is carried out in the absence of an organic template.

### Claim 2 (depends on 1)

The method of claim 1, wherein the hydrothermal treatment includes submerging the substrate in the third mixture in a vessel and sequentially pressuring to a pressure of up to 5 MPa and depressuring to ambient pressure, wherein the pressuring and depressuring is carried out for at least 5 cycles.

### Claim 3 (depends on 1)

The method of claim 1, wherein the silver-silicalite coating has a SiO2:Ag molar ratio of 25:1 to 100:1,
the silver-silicalite coating is in direct and continuous contact with substantially the entire exposed outside surface of the substrate, and
silver particles are formed at an outer surface of the silver-silicalite coating and substantially no silver particles are in contact with the surface of the substrate.

### Claim 4 (depends on 1)

The method of claim 1, wherein the silver-silicalite coating has a SiO2:Al2O3 molar ratio of 30:1 to 100:1.

### Claim 5 (depends on 1)

The method of claim 1, wherein the silver-silicalite coating has a SiO2:Al2O3 molar ratio of 50:1 to 80:1.

### Claim 6 (depends on 1)

The method of claim 1, wherein the hydrothermal treatment is carried out at a temperature range of 120 to 220° C. for 20 to 55 hours.

### Claim 7 (depends on 1)

The method of claim 1, wherein the hydrothermal treatment is carried out at a temperature range of 160 to 190° C. for 40 to 50 hours.

### Claim 8 (depends on 1)

The method of claim 1, wherein the silver-silicalite coating comprises silver nanoparticles having an average particle diameter of 10-200 nm.

### Claim 9 (depends on 8)

The method of claim 8, wherein the silver-silicalite coating further comprises rhombohedral crystals of the ZSM-5 zeolite decorated with the silver nanoparticles.

### Claim 10 (depends on 8)

The method of claim 8, wherein the silver-silicalite coating further comprises hexagonal lattice crystals of the ZSM-5 zeolite decorated with the silver nanoparticles.

### Claim 11 (depends on 1)

The method of claim 1, wherein the silver-silicalite coating comprises 35 to 45 wt. % O, 0.5 to 5 wt. % Al, 20 to 35 wt. % Si, 1 to 8 wt. % Cr, 10 to 25 wt. % Fe, 0.5 to 5 wt. % Ni, 0.5 to 5 wt. % Cu, and 1 to 10 wt. % Ag, wherein wt. % is based on a total weight of the silver-silicalite coating.

### Claim 12 (depends on 1)

The method of claim 1, wherein the silver-silicalite coating is at least partially enfolded by a polymer.

### Claim 13 (depends on 12)

The method of claim 12, wherein the polymer is at least one selected from the group consisting of a polyethylene glycol, a poly (ethylenimine), a poly (N-isopropyl acrylamide), a poly (2-hydroxyethyl methacrylate), a dendritic polymer, a polysaccharide, a poly (glycolic acid), and a poly (lactic acid).

### Claim 14 (depends on 13)

The method of claim 13, wherein the polymer is a polyethylene glycol.

### Claim 15 (depends on 1)

The method of claim 1, wherein the silver-silicalite coating further comprises coffin-shaped particles an average length in a range of 2 to 5 μm, an average width in a range of 0.5 to 2 μm, and an average height in a range of 0.5 to 2 μm, the coffin-shaped particles form agglomerates having an average diameter in a range of 4 to 10 μm.

### Claim 16 (depends on 1)

The method of claim 1, wherein the silver-silicalite coating is porous with a pore volume of 0.1 to 0.4 cm3/g.

### Claim 17 (depends on 1)

The method of claim 1, wherein the silver-silicalite coating is porous with a pore size distribution of 1 to 5 nm.

### Claim 18 (depends on 1)

The method of claim 1, wherein the coated stainless-steel substrate has a corrosion current from 0.04 to 0.1 ampere per square centimeter (A/cm2) to 0.01-0.025 A/cm2 lower in comparison to the same stainless-steel substrate without the silver-silicalite coating.