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 at least one 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, wherein the at least one lower protective layer based on titanium and zirconium has a thickness of greater than or equal to 2 nm and less than or equal to 5 nm and wherein the at least one 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, 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 at least one lower protective layer based on titanium and zirconium, wherein the at least one upper protective layer has a thickness of between 0.2 and 0.8 nm, and wherein the at least one lower protective layer based on titanium and zirconium is in contact with the at least one upper protective layer, and at least one dielectric layer based on silicon nitride and/or aluminum nitride located above at least a part of the at least one functional layer and below the at least one lower protective layer based on titanium and zirconium, wherein the at least one dielectric layer based on silicon nitride and/or aluminum nitride has a thickness of less than or equal to 50 nm and of greater than or equal to 15 nm and wherein the at least one dielectric layer based on silicon nitride and/or aluminum nitride is in contact with the at least one lower protective 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, 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 at least one dielectric layer based on silicon nitride and/or aluminum nitride has a thickness: of less than or equal to 50 nm, and of greater than or equal to 20 nm.

7. The material as claimed in claim 1, wherein the at least one 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, and a functional layer based on niobium nitride.

8. The material as claimed in claim 7, wherein the functional layer is chosen from a functional metal layer based on silver or on a silver-containing metal alloy and wherein the stack further comprises at least one blocking layer located below and in contact with the functional metal layer based on silver or on a silver-containing metal alloy and/or at least one blocking layer located above and in contact with the functional metal layer based on silver or on a silver-containing metal alloy; 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.

9. The material as claimed in claim 7, wherein the functional layer is chosen from a functional metal layer based on silver or on a silver-containing metal alloy, and wherein the stack further comprises: a coating based on dielectric materials located below the functional metal layer based on silver or on a silver-containing metal alloy, the coating comprising at least one dielectric layer based on silicon and/or aluminum nitride, a coating based on dielectric materials located above the functional metal layer based on silver or on a silver-containing metal alloy, the coating comprising at least one dielectric layer based on silicon and/or aluminum nitride, and the protective coating.

10. 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.

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

12. The material as claimed in claim 1, wherein the at least one lower protective layer based on titanium and zirconium is in oxidized form.

13. The material as claimed in claim 1, wherein the at least one lower protective layer based on titanium and zirconium is in oxidized or nitrided form.

14. A process for the preparation of the material of claim 1, wherein the material comprises the transparent substrate coated with the stack of thin layers deposited by cathode sputtering, the process comprising the sequence of the following stages: depositing the at least one functional layer on the transparent substrate, then depositing the at least one dielectric layer based on silicon and/or aluminum nitride above the at least one functional layer, then depositing the lower protective layer based on titanium and zirconium, these two metals being in a metal, oxidized or nitrided form, above the at least one dielectric layer based on silicon and/or aluminum nitride, depositing the upper protective layer of carbon, obtained by sputtering of a carbon target on the lower protective layer based on titanium and zirconium.

15. A method of manufacturing a glazing comprising incorporating the material as claimed in claim 1 into the glazing.

Description

EXAMPLES

(1) Stacks of thin layers defined below are deposited on substrates made of clear soda-lime glass with a thickness of 4 mm.

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

(3) 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.

(4) 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

(5) The substrates coated with stacks which are protected according to the invention can be tempered and bent.

(6) 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

(7) Different tests were carried out on the material according to the invention in order to evaluate the mechanical strength of the stack: Erichsen scratch test (EST), Erichsen brush test (EBT), before and after tempering, at 1000 cycles, Opel test at 2000 cycles, Cleaning test.

(8) 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.

(9) 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.

(10) 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.

(11) The cleaning test consists of three passes of the substrate through the washing machine.

(12) The material according to the invention satisfies each of these tests and gives, from the viewpoint of the scratch resistance, excellent results.