Glass sheet coated with a stack of thin layers and with an enamel layer

1. A material comprising a glass sheet coated on at least one portion of one of the faces thereof with a stack of thin layers comprising at least one layer based on a nitride, said stack being coated on at least one portion of its surface with an enamel layer comprising bismuth, said stack further comprising, in contact with the enamel layer, a contact layer, which is based on an oxide.

2. The material as claimed in claim 1 , wherein the at least one layer based on a nitride comprises a nitride of at least one element selected from aluminum, silicon, zirconium, and titanium.

3. The material as claimed in claim 2 , wherein the at least one layer based on a nitride is a layer based on silicon nitride.

4. The material as claimed in claim 1 , wherein the contact layer comprises an oxide of at least one element selected from aluminum, silicon, titanium, zinc, zirconium, and tin.

5. The material as claimed in claim 4 , wherein the contact layer is a layer based on silicon oxide.

6. The material as claimed in claim 1 , wherein at least one layer based on a nitride is in contact with the contact layer.

7. The material as claimed in claim 1 , wherein the contact layer has a physical thickness of at least 40 nm.

8. The material as claimed in claim 1 , wherein the stack comprises at least one functional layer.

9. The material as claimed in claim 8 , wherein the at least one functional layer is an electrically conductive functional layer.

10. The material as claimed in claim 9 , wherein at least one electrically conductive functional layer is selected from metal layers and layers of a transparent conductive oxide.

11. The material as claimed in claim 10 , wherein the metal layers are silver or niobium layers, and the layers of a transparent conductive oxide are layers of indium tin oxide, doped tin oxides, doped zinc oxides.

12. The material as claimed in claim 1 , wherein the enamel layer is based on bismuth zinc borosilicate.

13. The material as claimed in claim 12 , wherein the enamel layer has a chemical composition comprising the following oxides, in contents by weight that vary within the limits mentioned below:

B 2 O 3

 1-10%,

SiO 2

15-40%

Bi 2 O 3

 5-45%,

ZnO

 7-25%.

14. The material as claimed in claim 13 , wherein the enamel layer has a chemical composition comprising the following oxides, in contents by weight that vary within the limits mentioned below:

B 2 O 3

2-8%,

SiO 2

20-35%

Bi 2 O 3

10-40%,

ZnO

 8-20%.

15. The material as claimed in claim 1 , wherein the enamel layer is opaque, of black hue, and forms a strip at the periphery of the glass sheet.

16. A glazing comprising at least one material as claimed in claim 1 .

17. The glazing as claimed in claim 16 , wherein the glazing is a glazing for a motor vehicle roof, wherein the face of the glass sheet supporting the stack of thin layers and the enamel layer is the inner face of the glazing, said glass sheet being mechanically reinforced and/or laminated with at least one other glass sheet by means of a lamination interlayer.

18. A process for manufacturing a material as claimed in claim 1 , comprising depositing a stack of thin layers comprising at least one layer based on a nitride on at least one portion of a face of a glass sheet, then depositing, on at least one portion of the surface of said stack, an enamel layer comprising bismuth.

19. The process as claimed in claim 18 , wherein at least one portion of the stack of thin layers is deposited by chemical vapor deposition or by sputtering.

20. The process as claimed in claim 18 , wherein the deposition of the enamel layer comprises a step of firing at a temperature of at least 600° C.

21. The process as claimed in claim 20 , wherein the firing is during a bending and/or tempering treatment of the glass sheet.