SOLAR-CONTROL OR LOW-EMISSIVITY GLAZING COMPRISING AN UPPER PROTECTIVE LAYER

Abstract

A material includes a transparent substrate coated with a stack of thin layers including at least one silver-based functional metal layer. The stack includes a dielectric layer based on silicon and/or aluminum nitride located above a silver-based functional metal layer and an upper protective layer based on zirconium titanium oxide located above the dielectric layer based on silicon and/or aluminum nitride and exhibiting a ratio by weight of titanium to zirconium Ti/Zr of between 60/40 and 90/10.

Claims

1. A material comprising: a transparent substrate coated with a stack of thin layers comprising at least one silver-based functional metal layer, wherein the stack comprises: a dielectric layer based on silicon and/or aluminum nitride located above a silver-based functional metal layer, and an upper protective layer based on zirconium titanium oxide located above the dielectric layer based on silicon and/or aluminum nitride and exhibiting a ratio by weight of titanium to zirconium Ti/Zr of between 60/40 and 90/10.

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

3. The material as claimed in claim 1, characterized in 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.

4. The material as claimed in claim 1, wherein the dielectric layer based on silicon and/or aluminum nitride is in contact with the upper protective layer based on zirconium titanium oxide.

5. The material as claimed in claim 1, wherein the ratio by weight of titanium to zirconium Ti/Zr is between 60/40 and 70/30.

6. 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 dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that each functional metal layer is positioned between two dielectric coatings.

7. The material as claimed in claim 1, wherein the stack comprises at least one blocking layer located below and in contact with a silver-based functional metal layer.

8. The material as claimed in claim 1, wherein the stack comprises at least one blocking layer located above and in contact with a silver-based functional metal layer.

9. The material as claimed in claim 7, wherein the blocking 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.

10. The material as claimed in claim 1, wherein the stack comprises: a dielectric coating located below the silver-based functional metal layer, a first blocking layer, the silver-based functional metal layer, a second blocking layer, the dielectric layer located above the silver-based functional metal layer, an upper protective layer.

11. The material as claimed in claim 1, wherein the stack comprises: a dielectric coating located below the silver-based functional metal layer comprising at least one dielectric layer based on silicon and/or aluminum nitride, a first blocking layer, the silver-based functional metal layer, a second blocking layer, the dielectric coating located above the silver-based functional metal layer comprising at least one dielectric layer based on silicon and/or aluminum nitride, an upper protective layer.

12. The material as claimed in claim 1, wherein the substrate is made of glass.

13. The material as claimed in claim 1, wherein at least the substrate coated with the stack is bent and/or tempered.

14. A process for obtaining a material comprising a transparent substrate coated with a stack of thin layers deposited by cathode sputtering, optionally assisted by magnetic field; the process comprising the sequence of following stages: depositing at least one silver-based functional metal layer on the transparent substrate, then depositing at least one dielectric layer based on silicon and/or aluminum nitride above the silver-based functional metal layer, depositing an upper protective layer based on zirconium titanium oxide, exhibiting a ratio by weight of titanium to zirconium Ti/Zr of between 60/40 and 90/10, above the dielectric layer based on silicon and/or aluminum nitride.

15. The process as claimed in claim 14, further comprising subjecting the substrate coated with the stack of thin layers to a heat treatment at a temperature of greater than 400° C.

16. The material as claimed in claim 8, wherein the blocking 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 1, wherein the stack comprises: a dielectric coating located below the silver-based functional metal layer, the silver-based functional metal layer, the dielectric layer located above the silver-based functional metal layer, an upper protective layer.

18. The material as claimed claim 1, wherein the stack comprises: a dielectric coating located below the silver-based functional metal layer comprising at least one dielectric layer based on silicon and/or aluminum nitride, the silver-based functional metal layer, the dielectric coating located above the silver-based functional metal layer comprising at least one dielectric layer based on silicon and/or aluminum nitride, an upper protective layer.

19. The material as claimed in claim 12, wherein the glass is soda-lime-silica glass.

Description

EXAMPLES

[0087] Stacks of thin layers defined below are deposited on substrates made of clear soda-lime glass with a thickness of 4 mm.

[0088] For these examples, the conditions for deposition of the layers deposited by sputtering (“magnetron cathode” sputtering) are summarized in table 1 below.

[0089] The layers of zirconium titanium oxide are deposited from a TiZrO.sub.x ceramic target. The ratio of titanium to zirconium Ti/Zr in the target is 64:36 by weight, corresponding to 77:23 by atoms. The ratio of titanium to zirconium Ti/Zr in the layer is virtually equivalent to that of the target.

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% - 2.00 under Ag by weight) N.sub.2: 40-70% Si.sub.3N.sub.4 Si:Al (92:8% 2-15*10.sup.−3 mbar  Ar: 30-60% - 2.06 over Ag by weight) N.sub.2: 40-70% 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% - 2.32 O.sub.2 12% TiZrO TiZrO.sub.x 2-4*10.sup.−3 mbar Ar 90% - 2.32 O.sub.2 10% at.: by atoms; *at 550 nm

[0090] The materials and the physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating of which the stacks are composed are listed in the table below as a function of their positions with regard to the substrate carrying the stack.

[0091] The substrates coated with stacks protected according to the invention can be tempered or bent and do not need to be marginated when they are fitted as a double glazing.

TABLE-US-00002 Glazing Comparative Invention Upper protective layer TiZrO.sub.x — 3 TiO.sub.x 3 — Dielectric 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 Dielectric coating Si.sub.3N.sub.4 35 35 Substrate (mm) glass 4 4

I. Resistance to the High Humidity Test and the Cleveland Test

[0092] In order to show the improvement in the lifetime of the stack, a High Humidity (HH) test and a Cleveland (CV) test are carried out.

[0093] The high humidity (HH) test consists in storing samples at 95% relative humidity and at 40° C. and observing the possible presence of defects, such as corrosion pits.

[0094] The Cleveland test consists of subjecting the coated substrate to the following cycle: [0095] rise in temperature from 23° C. to 56° C. in 45 min, [0096] maintenance at 56° C. and 95% humidity for 2 hours, [0097] fall from 56° C. to -15° C. in 1h 30, [0098] maintenance at -15° C. for 1 hour, [0099] rise in temperature from -15° C. to 23° C. in 45 min.

[0100] The following assessment indicators were used to record the possible detrimental changes: [0101] “+”: no defect, [0102] “0”: a few sites of corrosion, [0103] “−”: presence of defects.

TABLE-US-00003 Test Comparison Invention HH  7 days − + 56 days − 0 CV 28-56 days   − + 56 days − +

[0104] The materials comprising the protective layer according to the invention withstand the two tests for at least 56 days, whereas the comparative material exhibits defects from 7 days in the HH test and from 26 days in the CV test. The solution of the invention makes it possible to significantly improve the lifetime of the material, in particular by a factor of 2 or 8 according to the HH or CV test.

II. Variations in Electrical and Colorimetric Properties

[0105] The colorimetric variations (AE) and the sheet resistance variations (ARsq) were evaluated: [0106] AE represents the variation between the L*, a* and b* values obtained for a coated substrate before and after having been subjected to an HH or CV test. The L*, a* and b* values corresponding to the colors in reflection, on the side of the layers, in the LAB system, measured according to the D65 illuminant, are measured before and after the tests. The variation is calculated in the following way: ΔE=(Δa*.sup.2+Δb*.sup.2+ΔL*.sup.2).sup.1/2. [0107] ΔRsq corresponds to the variation between the sheet resistance values obtained for a coated substrate before and after having been subjected to an HH or CV test. The sheet resistance (Rsq), corresponding to the resistance of a sample with a width equal to the length (for example 1 meter) and of any thickness, is measured with a Nagy device.

TABLE-US-00004 Test Comparison Invention HH ΔE 56 days 2.1 1.4 ΔRsq 56 days 0.3 0.2 CV ΔE 56 days 1.7 0.9 ΔRsq 56 days 0.6 0.4
Ill. Evaluation of the Mechanical Strength

[0108] In order to evaluate the mechanical strength of the stack, different tests were carried out on the material according to the invention: [0109] Erichsen Brush Test (EBT), before and after tempering, at 1000 cycles, [0110] Opel test at 2000 cycles, [0111] Cleaning test.

[0112] The Erichsen brush test (EBT) consists in subjecting different coated substrates, before tempering (EBT) and after tempering (HT-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.

[0113] 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.

[0114] The cleaning test consists of three passes of the substrate through a washing machine.

[0115] The material according to the invention satisfies each of its tests.

IV. Evaluation of the Resistance Subsequent to a Long-Lasting Heat Treatment

[0116] In order to evaluate the resistance to long heat treatments, the material according to the invention protected by an upper protective layer made of TiZrO.sub.x was heated at 400° C. for 500 h. No deterioration is observed.

[0117] The main optical characteristics measured for the coated substrates according to the invention, before and after heat treatment, are summarized in the table below: [0118] L*R, a*R and b*R indicate the colors in reflection L*, a* and b* in the L*a*b* system measured according to the D65 illuminant at 2° , observer on the side of the stack and thus measured perpendicularly to the glazing; [0119] LR indicates: the light reflection in the visible region in %, measured according to D65 illuminant at 2° , observer on the side of the stack; [0120] L*T, a*T and b*T indicate the colors in transmission L*, a* and b* in the L*a*b* system measured according to the D65 illuminant at 2° Observer and thus measured perpendicularly to the glazing; [0121] LT indicates: the light transmission in the visible region in %, measured according to the D65 illuminant at 2° Observer; [0122] Abs. indicates: the light absorption in the visible region in %, measured according to the D65 illuminant at 10° Observer; [0123] Rsq indicates the sheet resistance.

TABLE-US-00005 Color in reflection Color in transmission Factors % Rsq L*R a*R b*R L*T a*T b*T LR LT Abs — Before HT 23.7 −0.83 −9.05 92.81 −1.9 −0.48 4.01 82.53 13.46 9.43 After HT 23.9 −0.85 −8.91 92.7 −2.06 −0.65 4.08 82.22 13.71 9.36 Variation ΔL*R Δa*R Δb*R ΔL*T Δa*T Δb*T ΔLR ΔLT ΔAbs ΔRsq 0.2 −0.02 0.14 −0.11 0.16 0.17 0.07 0.31 −0.25 −0.07 ΔE 0.26

[0124] After heat treatment, the visual examination of the material according to the invention does not make it possible to perceive the presence of a site of corrosion.