GLAZING COMPRISING A CARBON-BASED UPPER PROTECTIVE LAYER

Abstract

A material includes a transparent substrate coated with a stack of thin layers acting on infrared radiation including at least one functional layer. The stack includes a carbon-based upper protective layer within which the carbon atoms are essentially in an sp.sup.2 hybridization state and the upper protective layer is deposited above at least a part of the functional layer and exhibits a thickness of less than 1 nm.

Claims

1. A material comprising a transparent substrate coated with a stack of thin layers acting on infrared radiation comprising at least one functional layer, wherein the stack comprises a carbon-based upper protective layer within which the carbon atoms are essentially in an sp.sup.2 hybridization state and the upper protective layer is deposited above at least a part of the functional layer and exhibits a thickness of less than 1 nm.

2. The material as claimed in claim 1, wherein the material is configured to undergo a heat treatment.

3. The material as claimed in claim 1, wherein said functional layer is deposited between coatings based on dielectric materials.

4. The material as claimed claim 1, wherein the material is untempered.

5. The material as claimed in claim 1, wherein the material is tempered and bent.

6. The material as claimed in claim 1, wherein the stack additionally comprises a lower protective layer based on metals chosen from titanium, zinc, tin, zirconium and/or hafnium, these metals being in the metal, oxidized, nitrided or oxynitrided form.

7. The material as claimed in claim 6, wherein the lower protective layer is chosen from a layer: of titanium; of zirconium; of hafnium; of titanium and of zirconium; of titanium, of zirconium and of hafnium; of zinc and of tin; of titanium nitride; of zirconium nitride; of hafnium nitride; of titanium and zirconium nitride; of titanium, zirconium and hafnium nitride; of titanium oxide; of zirconium oxide; of hafnium oxide; of titanium and zirconium oxide; of titanium, zirconium and hafnium oxide; of zinc and tin oxide.

8. The material as claimed in claim 6, wherein the lower protective layer has a thickness: of less than or equal to 4 nm, and/or of greater than or equal to 1 nm.

9. The material as claimed in claim 6, wherein the upper protective layer has a thickness of between 0.2 and 0.8 nm.

10. The material as claimed in claim 1, wherein the stack comprises a dielectric layer based on silicon and/or aluminum nitride located above at least a part of the functional layer.

11. The material as claimed in claim 10, wherein the dielectric layer based on silicon and/or aluminum nitride has a thickness: of less than or equal to 50 nm, and/or of greater than or equal to 20 nm.

12. The material as claimed in claim 10, wherein the dielectric layer based on silicon and/or aluminum nitride is below the lower protective layer and in contact with the lower protective layer.

13. The material as claimed in claim 1, wherein the functional layer is chosen from: a functional metal layer based on silver or on a silver-containing metal alloy, a functional metal layer based on niobium, a functional layer based on niobium nitride.

14. The material as claimed in claim 1, wherein the stack of thin layers comprises at least one silver-based functional metal layer and at least two coatings based on dielectric materials, each coating comprising at least one dielectric layer, so that each functional metal layer is positioned between two coatings based on dielectric materials.

15. The material as claimed in claim 13, wherein the stack comprises at least one blocking layer located below and in contact with a silver-based functional metal layer and/or at least one blocking layer located above and in contact with a silver-based functional metal layer; the blocking layer or layers are based on a metal chosen from niobium Nb, tantalum Ta, titanium Ti, chromium Cr or nickel Ni or based on an alloy obtained from at least two of these metals.

16. The material as claimed in claim 13, wherein the stack comprises: a coating based on dielectric materials located below a silver-based functional metal layer, the coating comprising at least one dielectric layer based on silicon and/or aluminum nitride, a silver-based functional metal layer, a coating based on dielectric materials located above the silver-based functional metal layer, the coating comprising at least one dielectric layer based on silicon and/or aluminum nitride, an upper protective layer.

17. The material as claimed in claim 1, wherein the transparent substrate is: made of glass, or made of polymer.

18. A process for the preparation of a material comprising a transparent substrate coated with a stack of thin layers deposited by cathode sputtering, the process comprising the sequence of following stages: depositing at least one functional layer on the transparent substrate, then depositing at least one dielectric layer based on silicon and/or aluminum nitride above the functional layer, then depositing a carbon-based upper protective layer, within which the carbon atoms are essentially in an sp.sup.2 hybridization state, by sputtering of a carbon target, wherein the upper protective layer exhibits a thickness of less than 1 nm.

19. A method of using the material as claimed in claim 1, comprising: manufacturing a glazing.

20. The process recited in claim 18, further comprising: depositing a lower protective layer after the depositing at least one dielectric layer.

Description

EXAMPLES

[0103] Stacks of thin layers defined below are deposited on substrates made of clear soda-lime glass with a thickness of 4 mm.

[0104] For these examples, the conditions for deposition of the layers deposited by sputtering (“magnetron cathode” sputtering” are summarized in table 1 below.

[0105] The layer of carbon of graphite type is deposited by magnetron sputtering of a graphite target under an atmosphere comprising argon at a low power of approximately 10 kW.

TABLE-US-00001 TABLE 1 Targets Deposition employed pressure Gases Index* Si.sub.3N.sub.4 Si:Al (92:8% 2-15*10.sup.−3 mbar Ar:30-60% − N.sub.2:40-70% 2.00 by weight) AZO Zn:Al (2% 1.5*10.sup.−3 mbar Ar 91% − O.sub.2 9% 1.90 by weight) NiCr Ni:Cr (80:20% 1-5*10.sup.−3 mbar Ar at 100% — at.) Ag Ag 2-3*10.sup.−3 mbar Ar at 100% — TiO.sub.2 TiO.sub.x 1.5*10.sup.−3 mbar Ar 88% − O.sub.2 12% 2.32 C Graphite 1.5*10.sup.−3 mbar Ar at 100% 2.25 at.: by atoms; *: at 550 nm

[0106] The substrates coated with stacks which are protected according to the invention can be tempered and can be bent.

TABLE-US-00002 Glazing Inv. 1 Inv. 2 Comp. Upper protective layer C 0.8 0.8 — Lower protective layer TiO.sub.x 3 1.5 1.5 Antireflective coating Si.sub.3N.sub.4 35 35 35 ZnO — 5 5 Blocking layer BO NiCr 0.4 0.7 0.7 Functional layer Ag 7 10 10 Blocking layer BU NiCr 0.7 0.7 0.7 Antireflective coating ZnO — 5 5 Si.sub.3N.sub.4 35 30 30 Substrate (mm) Glass 4 4 4

[0107] Different tests were carried out on the material according to the invention in order to evaluate the mechanical strength of the stack: [0108] Steel wool test, [0109] Harp test.

[0110] The steel wool test and the harp test are two tests which consist in deliberately producing scratches at the surface of the material on the side of the stack.

[0111] The steel wool test consists in carrying out a certain number of two-and-fro movements by rubbing the coated material on the side of the stack with a piece of steel wool with a constant pressure.

[0112] The objective of the harp test is to simulate the rubbing conditions to which a substrate coated with a stack may be subjected in a harp trolley. This test consists of rubbing the coated material on the side of the stack with a string originating from a harp trolley.

[0113] These two tests were carried out on uncleaned substrates and on cleaned substrates. The cleaned substrates undergo, after producing the scratches, a cleaning stage consisting of several passes through a washing machine.

[0114] The substrates are subsequently tempered, for example at 650′C for 5 minutes. The state of the material is then assessed visually.

[0115] A grade is assigned as a function of the following scale of grades: [0116] 1: glass not or very slightly scratched (0 to 5 scratches), [0117] 2: glass slightly scratched (up to 20 scratches), [0118] 3: glass quite scratched (up to 50 scratches), [0119] 4: glass highly scratched (number of scratches greater than 50).

TABLE-US-00003 Without With Example Test cleaning cleaning Comp. Steel Wool 4 4 Harp 3 3 Inv. 2 Steel Wool 1 1 Harp 1 1

[0120] The material according to the invention satisfies each of these tests and gives, from the viewpoint of the scratch resistance, excellent results. Furthermore, the washing stage does not modify the good scratch resistance properties obtained.