# US 4,395,432 A · .beta.-Alumina coating

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- Number: US 4,395,432 A
- Document ID: US4395432A
- Status: Granted
- Kind: A
- Application number: 06/331,107
- Filed: 1981-12-16
- Granted: 1983-07-26
- Earliest claimed: 1981-12-16
- Assignees: Westinghouse Electric Corp.
- Inventors: Frank D. Rizzelli; Kimon Papadopoulos
- Web page: https://patentgrep.com/patent/US4395432A

## CPC

- C04B 35/113: based on beta-aluminium oxide
- C03C 17/23: Oxides (C03C17/02 takes precedence)
- C04B 41/5031: {Alumina}
- C23C 4/11: Oxides
- H01M 10/3918: {characterised by the electrolyte}
- C03C 2217/214: Al2O3
- C03C 2217/23: Mixtures
- C03C 2218/17: from a solid phase
- Y02E 60/10: Energy storage using batteries
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- 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)
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Disclosed is a method of coating a substrate with .beta.-alumina, a compound of alumina and an alkali metal oxide, while maintaining its electrically conductive properties. A powdered mixture is formed of the .beta.-alumina and a carbonate of the alkali metal. The mixture is sprayed through a source of heat sufficient to melt it onto the substrate. A plasma spray torch can be used to melt spray the mixture.

## Claims

### Claim 1

A method of coating a substrate with .beta.-alumina, a compound of alumina and an alkali metal oxide, comprising:
(1) forming a powdered mixture of about 80 to about 95% by weight .beta.-alumina and about 5 to about 20% by weight of a carbonate of an alkali metal; and
(2) spraying said powdered mixture through a source of heat sufficient to melt it, and onto said substrate.

### Claim 2 (depends on 1)

A method according to claim 1 wherein said .beta.-alumina is a compound of about 80 to about 95 mole percent M.sub.2 O and about 5 to about 20 mole percent Al.sub.2 O.sub.3, where M is selected from the group consisting of Na, Li, K, and mixtures thereof.

### Claim 3 (depends on 2)

A method according to claim 2 wherein M is Na.

### Claim 4 (depends on 1)

A method according to claim 1 wherein said mixture comprises about 5 to about 10% by weight of said carbonate and about 90 to about 95% by weight .beta.-alumina.

### Claim 5 (depends on 1)

A method according to claim 1 wherein said mixture has a particle size less than 100 mesh.

### Claim 6 (depends on 1)

A method according to claim 1 wherein said mixture is heated with a plasma spray torch.

### Claim 7 (depends on 1)

A method according to claim 1 wherein the alkali metal in said carbonate is the same alkali metal that is in said .beta.-alumina.

### Claim 8

A method of coating a substrate with a compound having the general formula nM.sub.2 O. (1-n)Al.sub.2 O.sub.3 where n is 0.005 to 0.20 amd M is selected from the group consisting of Na, Li, K, and mixtures thereof, comprising:
(1) forming a mixture having a particle size less than 100 mesh of about 80 to about 95% by weight of said compound and about 5 to about 20% M.sub.2 CO.sub.3 ;
(2) melt spraying said mixture onto said substrate using a plasma spray torch.

### Claim 9 (depends on 8)

A method according to claim 8 wherein M is Na.

### Claim 10 (depends on 8)

A method according to claim 8 wherein said mixture is about 5 to about 10% by weight M.sub.2 CO.sub.3 and about 90 to about 95% by weight of said compound.