# US 4,400,412 A · Thermochromic vanadium oxide coated glass

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- Number: US 4,400,412 A
- Document ID: US4400412A
- Status: Granted
- Kind: A
- Application number: 06/344,860
- Filed: 1982-02-01
- Granted: 1983-08-23
- Earliest claimed: 1982-02-01
- Assignees: PPG Industries, Inc.
- Inventors: J. Kevin Scanlon; Charles B. Greenberg
- Web page: https://patentgrep.com/patent/US4400412A

## CPC

- C03C 17/245: by deposition from the vapour phase
- C03C 2217/218: V2O5, Nb2O5, Ta2O5
- C03C 2218/152: by cvd
- 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

## Abstract

A method is disclosed for producing a thermochromic window comprising a glass substrate and a coating containing VO.sub.2 by chemical vapor deposition employing vanadium n-propylate in an oxidizing atmosphere.

## Claims

### Claim 1

A method for making a thermochromic window comprising the steps of:
a. heating a glass substrate to a sufficient temperature to convert vanadium n-propylate to vanadium oxide;
b. vaporizing vanadium n-propylate;
c. conveying the vaporized vanadium n-propylate to said substrate in an atmosphere sufficiently oxidizing to form a thermochromic film comprising VO.sub.2 but insufficiently oxidizing to form a film which is not thermochromic as a result of the proportion of V.sub.2 O.sub.5 ;
d. contacting a surface of said heated glass substrate with said vapor of vanadium n-propylate in said oxidizing atmosphere to deposit thereupon a film containing VO.sub.2.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the glass substrate is heated to a temperature of at least 400.degree. C. and said atmosphere comprises a mixture of inert gas and oxygen.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the glass substrate is heated to a temperature of at least 500.degree. C. and said atmosphere comprises a mixture of nitrogen and oxygen.

### Claim 4 (depends on 3)

The method according to claim 3, wherein said atmosphere comprises 90 percent by volume nitrogen and 10 percent by volume oxygen.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the film containing VO.sub.2 is deposited to a thickness of about 100 to 1,500 Angstroms.