Substrates coated with a multi-film functional coating

• US 20060210810A1
• Filed: 03/21/2005
• Published: 09/21/2006
• Est. Priority Date: 03/21/2005
• Status: Active Grant

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Walck, Scott D., Harris, Caroline S., Steffek, Cory D.
• Granted Patent: US 7,438,948 B2
• Time in Patent Office: Days
• US Class Current: 428/432
• CPC Class Codes: C03C 17/002 for flat glass, e.g. float glass
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2218/152 by cvd
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A method for forming a coated substrate is disclosed. The method comprises depositing an undercoating layer and depositing a functional coating comprising a material which can be present in more than one crystal structure over the undercoating layer, wherein there is a critical deposition thickness at which the functional coating transforms from a first polycrystalline film made up predominantly of the material having a first crystal structure to a second polycrystalline film made up predominantly of the same material having a second crystal structure.

Claims

1. A method for forming a coated substrate comprising:

a. depositing an undercoating layer; and

b. depositing a functional coating comprising a material which can be present in

more than one crystal structure over the undercoating layer, wherein there is a critical deposition thickness at which the functional coating transforms from a first polycrystalline film made up predominantly of the material having a first crystal structure to a second polycrystalline film made up predominantly of the same material having a second crystal structure which is different than the first crystal structure.

2. The method according to claim 1, wherein the functional coating is deposited at a thickness less than the critical deposition thickness and comprises a single polycrystalline film made up predominantly of material having a first crystal structure.

3. The method according to claim 1, wherein the functional coating is deposited at a thickness greater than the critical deposition thickness and is a multi-film coating comprising a first polycrystalline film made up predominantly of the material having a first crystal structure and a second polycrystalline film made up predominantly of the same material having a second crystal structure.

4. The method of claim 1, wherein depositing the undercoating layer is accomplished using CVD, spray pyrolysis, MSVD, PECVD, or PACVD.

5. The method according to claim 1, wherein the thickness of the deposited undercoating layer is at least 1 nm.

6. The method according to claim 1, wherein the undercoating layer comprises a material having the rutile crystal structure.

7. The method according to claim 6, wherein the undercoating layer comprises a material selected from tin oxide, germanium dioxide, beta manganese dioxide, chromium (IV) oxide, iridium oxide, osmium (IV) oxide, ruthenium (IV) oxide, tantalum (IV) oxide, niobium (IV) oxide, molybdenum (IV) oxide, tungsten (IV) oxide, lead (IV) oxide and mixtures thereof.

8. The method according to claim 1, wherein the undercoating layer comprises a material having the brooktite crystal structure.

9. The method according to claim 8, wherein the undercoating layer comprises tellurium oxide.

10. The method according to claim 1, wherein depositing the functional coating is accomplished by CVD, spray pyrolysis, MSVD, PECVD, or PACVD.

11. The method according to claim 10, wherein the thickness of the deposited functional coating ranges from 10 nm to 250 nm.

12. The method according to claim 1, wherein the functional coating is a photocatalytic coating.

13. The method of claim 12, wherein the photocatalytic coating comprises at least one metal oxide selected from titanium oxide, iron oxide, tungsten oxide, zinc oxide, tin oxide, zinc/tin oxide, calcium titanium oxide, molybdenum oxide, niobium oxide, vanadium oxide and mixtures thereof.

14. The method of claim 13, wherein the undercoating comprises tin oxide having the rutile crystal structure and the photocatalytic coating comprises titanium oxide.

15. The method according to claim 1, wherein the substrate is glass.

16. The method according to claim 15, wherein the method is carried out on a float glass line during a glass making operation.

17. The method according claim 13, wherein the method further comprises the step of activating the photocatalytic coating.

18. A method for forming a coated substrate comprising:

a. depositing an undercoating layer selected from tin oxide, germanium dioxide, beta manganese dioxide, chromium (IV) oxide, iridium oxide, osmium (IV) oxide, ruthenium (IV) oxide, tantalum (IV) oxide, niobium (IV) oxide, molybdenum (IV) oxide, tungsten (IV) oxide, lead (IV) oxide and mixtures thereof; and

b. depositing a functional coating comprising a material which can be present in more than one crystal structure over the undercoating layer, wherein the functional coating comprises a first polycrystalline film made up predominantly of the material having a first crystal structure and a second polycrystalline film made up predominantly of the same material having a second crystal structure which is different from the first crystal structure.

19. The method according to claim 18, wherein the first crystal structure is the rutile crystal structure and the second crystal structure is the anatase crystal structure.

23. The coated substrate according to claim 19, wherein the coated substrate is incorporated into an IG unit.

20. A coated substrate comprising:

a. an undercoating layer; and

b. photocatalytic coating over the undercoating layer comprising a first polycrystalline film made up predominantly of a material having a first crystal structure and a second polycrystalline film made up predominantly of the same material having a second crystal structure which is different from the first crystal structure.

21. The method according to claim 20, wherein the undercoating layer comprises a material selected from tin oxide, germanium dioxide, beta manganese dioxide, chromium (IV) oxide, iridium oxide, osmium (IV) oxide, ruthenium (IV) oxide, tantalum (IV) oxide, niobium (IV) oxide, molybdenum (IV) oxide, tungsten (IV) oxide, lead (IV) oxide and mixtures thereof.

22. The coated substrate according to claim 20, wherein the first crystal structure is the rutile crystal structure and the second crystal structure is the anatase crystal structure.

24. A method for adjusting the critical deposition thickness of a functional coating made up predominantly of material having a first crystal structure and having a first lattice parameter, comprising:

including an undercoating layer made up predominantly of material having a second crystal structure and having a second lattice parameter under the functional coating; and

changing the first and/or the second lattice parameter.

25. The method according to claim 24, wherein first lattice parameter is changed by doping the functional coating layer.