GLAZING COMPRISING A PROTECTIVE COATING

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 protective coating deposited above at least a part of the functional layer. The protective coating includes at least one lower protective layer based on titanium and zirconium, these two metals being in the metal, oxidized or nitrided form, and at least one upper protective layer of carbon, within which layer the carbon atoms are essentially in an sp.sup.2 hybridization state, located above the layer based on titanium and zirconium.

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 protective coating deposited above at least a part of the functional layer, the protective coating comprising: at least one lower protective layer based on titanium and zirconium, these two metals being in the metal, oxidized or nitrided form, at least one upper protective layer of carbon, within which layer the carbon atoms are essentially in an sp.sup.2 hybridization state, located above the layer based on titanium and zirconium.

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, characterized in that it wherein the material is untempered.

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

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

6. The material as claimed in claim 1, wherein the lower protective layer has a thickness: of less than or equal to 5 nm, and/or of greater than or equal to 2 nm.

7. The material as claimed in claim 1, wherein the upper protective layer has a thickness of less than or equal to 5 nm.

8. The material as claimed in claim 1, wherein the upper protective layer has a thickness of less than 1 nm

9. The material as claimed in claim 1, 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 and below the lower protective layer based on titanium and zirconium.

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 in contact with the lower protective layer based on titanium and zirconium.

13. The material as claimed in claim 1, wherein the lower protective layer based on titanium and zirconium exhibits a ratio by weight of titanium to zirconium Ti/Zr of between 60/40 and 90/10.

14. 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.

15. 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.

16. The material as claimed in claim 14, 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.

17. The material as claimed in claim 14, wherein the stack comprises: a coating based on dielectric materials located below the 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, a protective coating.

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

19. 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 the following stages: depositing at least one functional layer on the transparent substrate, then depositing a lower protective layer based on titanium and zirconium, these two metals being in a metal, oxidized or nitrided form, above the dielectric layer based on silicon and/or aluminum nitride, depositing an upper protective layer of carbon, obtained by sputtering of a carbon target.

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

Description

EXAMPLES

[0097] Stacks of thin layers defined below are deposited on substrates made of clear soda-lime glass with a thickness of 4 mm.

[0098] For these examples, the conditions of the deposition of the layers deposited by sputtering (“magnetron cathode” sputtering) are summarized in table 1 below.

[0099] The layers of zirconium and titanium oxide are deposited from a TiZrO.sub.x ceramic target. The titanium to zirconium Ti/Zr ratio in the target is 64:36 by weight, corresponding to 77:23 biatoms. The ratio of titanium to zirconium Ti/Zr in the layer is virtually equivalent to that of the target.

TABLE-US-00001 TABLE 1 Deposition Targets employed pressure Gases Index* Si.sub.3N.sub.4 Si:Al (92:8% by 2-15*10.sup.−3 Ar: 30-60%- 2.00 weight) mbar N.sub.2: 40-70% NiCr Ni:Cr (80:20% at.) 1-5*10.sup.−3 mbar Ar at 100% — 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 TiZrO TiZrO.sub.x 2-4*10.sup.−3 mbar Ar 90%-O.sub.2 10% 2.32 C Graphite 1.5*10.sup.−3 mbar Ar at 100% 2.25 at. biatoms; *at 550 nm

[0100] The substrates coated with stacks which are protected according to the invention can be tempered and bent.

TABLE-US-00002 Glazing Comparative Invention Upper protective layer C 0.8 0.8 Lower protective layers TiZrO.sub.x — 3 TiO.sub.x 3 — Antireflective coating Si.sub.3N.sub.4 35 35 Blocking layer BO NiCr 0.4 0.4 Functional layer Ag 7 7 Blocking layer BU NiCr 0.7 0.7 Antireflective coating Si.sub.3N.sub.4 35 35 Substrate (mm) Glass 4 4

[0101] Different tests were carried out on the material according to the invention in order to evaluate the mechanical strength of the stack: [0102] Steel wool test, [0103] Harp test.

[0104] 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.

[0105] The steel wool test consists in carrying out a certain number of to-and-fro movements by rubbing the coated material on the side of the stack with a piece of steel wool with a constant pressure.

[0106] The objective of the harp test is to simulate the rubbing conditions to which the substrate coated with a stack may be subjected in a harp carriage. This test consists of rubbing the coated material on the side of the stack with a string originating from a harp carriage.

[0107] These two tests were carried out on cleaned substrates. The cleaned substrates undergo, after producing scratches, a cleaning stage consisting of several passes through a washing machine.

[0108] The substrates are subsequently tempered, for example for X minutes at XX° C. The state of the material is then assessed visually.

[0109] A grade is assigned as a function of the following scale of grades: [0110] 1: glass not or very slightly scratched (0 to 5 scratches), [0111] 2: glass slightly scratched (up to 20 scratches), [0112] 3: glass quite scratched (up to 50 scratches), [0113] 4: glass highly scratched (number of scratches greater than 50).

TABLE-US-00003 Example Test Grade Inv. 1 Steel Wool 4 Harp 3 Inv. 2 Steel Wool 1 Harp 1

[0114] 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. [0115] Erichsen scratch test (EST), [0116] Erichsen brush test (EBT), before and after tempering, at 1000 cycles, [0117] Opel test at 2000 cycles, [0118] Cleaning test.

[0119] The Erichsen brush test (EBT) consists in subjecting different coated substrates, before tempering (EBT) and after tempering (TT-EBT) to a certain number of cycles (1000) during which the stack, covered with water, is rubbed using a brush. It is considered that a substrate satisfies the test if no mark is visible to the naked eye. The test before tempering gives a good indication with regard to the ability of the glazing to be scratched during a washing operation. The test after tempering gives a good indication with regard to the propagation of the scratches after heat treatment.

[0120] The Erichsen scratch test (EST) consists in applying a force on the sample, in Newtons, using a tip (Van Laar tip, steel ball). Depending on the scratch resistance of the stack, different types of scratches can be obtained: continuous, noncontinuous, wide, narrow, and the like.

[0121] The Opel test makes it possible to evaluate the abrasion resistance. It is carried out in accordance with the standard EN1096-2 at 2000 cycles.

[0122] The cleaning test consists of three passes of the substrate through the washing machine.

[0123] The material according to the invention satisfies each of these tests and gives, from the viewpoint of the scratch resistance, excellent results.