Blue solar-resistant glazing in external reflection

Abstract

Transparent glass article for solar-protection glazing, comprising at least one clear glass substrate provided on at least one of its faces with a coating consisting of a stack of thin layers, said coating comprising the following succession of layers, starting from the surface of said substrate, a first layer based on silicon nitride with a thickness e1 of between 55 nm and 90 nm, a layer based on silicon nitride and zirconium with a thickness e2 of between 5 nm and 25 nm, a functional layer based on niobium, with a thickness of between 15 nm and 50 nm, a second layer based on silicon nitride with a thickness e3 of between 10 nm and 45 nm, in which the stack comprises only one layer based on niobium and in which the sum of the thicknesses e1+e2 is between 60 nm and 110 nm.

Description

Title of the invention: Blue anti-solar glazing with external reflection

[0001] The invention relates to insulating glazing known as solar control glazing, provided with stacks of thin layers, at least one of which is functional, i.e. it acts on solar and / or thermal radiation essentially by reflection and / or absorption of near (solar) or far (thermal) infrared radiation. The present invention relates more particularly to glazing with layer(s), in particular those intended mainly for the thermal insulation of buildings.

[0002] "Functional" or "active" layer(s) are understood to mean, within the meaning of the present application, the layer(s) of the stack which gives the stack the majority of its thermal properties. Most often, the stacks of thin layers equipping the glazing give it improved solar control properties essentially through the intrinsic properties of this or these active layer(s). A functional layer acts on the flux of solar radiation passing through said glazing, as opposed to the other layers of the stack, generally made of a dielectric material such as silicon oxide, titanium oxide or silicon nitride, having the function of chemical or mechanical protection of said functional layer.

[0003] Such glazings provided with stacks of thin layers act on the incident solar radiation either essentially by the absorption of the incident radiation by the functional layer, or essentially by reflection by this same layer.

[0004] They are grouped under the name of solar control glazing. They are marketed and used essentially either to ensure protection of the home from solar radiation and prevent overheating, or essentially to ensure thermal insulation of the home and prevent heat loss.

[0005] By antisolar, we mean in the sense of the present invention the ability of the glazing to limit the energy flow, in particular the solar infrared radiation (1RS) passing through it from the outside to the inside of the dwelling or passenger compartment.

[0006] In a known manner, the solar control properties of a glazing are given to it by a stack of layers, at least one of which is said to be functional, that is to say that it has properties of reflection and / or absorption of infrared rays while allowing at least part of the visible radiation to pass through.

[0007] To measure the solar control properties of glazing, the solar factor noted FS or g is often used in the field.

[0008] In a known manner, the solar factor g is equal to the ratio of the energy passing through the glazing (i.e. entering the room) and the incident solar energy. More particularly lately, it corresponds to the sum of the flow transmitted directly through the glazing and the flow absorbed by the glazing (including any stacks of layers possibly present on one of its surfaces) then possibly re-emitted towards the interior (the room). We are currently looking for glazing with the lowest possible g factor and at least less than 50% (0.5) preferably less than 40%, or even less than or equal to 30%.

[0009] The most efficient stacks currently marketed to achieve such performances incorporate at least one metallic layer of the silver type operating essentially in the mode of reflecting a major part of the incident IR (infrared) radiation. These stacks can be used mainly as low-emissivity (or low-e in English) glazing or as solar-protection glazing. These layers are however very sensitive to humidity and oxidation. They are therefore exclusively used in double glazing, on face 2 or 3 of the latter, to be protected from humidity. It is therefore not possible to deposit such layers on single glazing (also called monolithic). The stacks according to the present invention do not comprise such silver-based layers, or even gold or platinum-based layers, or only in very negligible quantities, in particular in the form of unavoidable impurities.

[0010] Likewise, the functional layers, or even the stacks, of the glass articles according to the invention are in principle free of nickel or copper.

[0011] Stacks with low emissive or antisolar properties are also known but based on functional layers of transparent conductive oxides (TCO) such as mixed oxides of tin and indium, such as for example the stacks described in publication US2009320824. However, to obtain glazings whose solar factor is less than 50%, it is necessary to deposit layer thicknesses of at least 100 nm. The deposition of such layers by magnetron-assisted sputtering techniques is therefore long and expensive.

[0012] Other stacks with anti-solar function have also been disclosed in the field, comprising functional layers based on metallic niobium or nitrided niobium, as described for example in application WO01 / 21540 or in application WO2009 / 112759.

[0013] In a glazing according to the invention, the so-called solar control stack can be arranged on the face of the glazing facing the interior of the building or the passenger compartment that it equips and in particular on face 2 of a single glazing, the faces being conventionally numbered from the outside to the inside.

[0014] By stack side, we mean the face of the glazing on which the stack is deposited. By glass side we mean the face of the glazing opposite that on which the stack is deposited, in principle not covered. For the purposes of this invention, the terms "external face" (or "external") and "internal face" or ("internal") refer to the position of the glazing when it is fitted to the building or vehicle for which it is intended.

[0015] We distinguish in this respect:

[0016] - the external light reflection RLext, i.e. the light reflection measured on the face of the glazing exposed to the outside of the building or the passenger compartment, and - the interior light reflection RLint, i.e. the light reflection measured on the face of the glazing facing inwards.

[0017] In other words, the interior light reflection RLintest is measured on the face provided with the stack of layers while the exterior light reflection RLextest is measured on the bare face of the glazing.

[0018] Generally speaking, all the luminous characteristics presented in the present description, in particular, the luminous transmission TL and the luminous reflections Rl, as well as the factor g, are obtained according to the principles and methods described in the standard NF EN 410 (2011) relating to the determination of the luminous and energy characteristics of glazing used in glass for construction.

[0019] In certain building glazing configurations, glazing is sought which also exhibits a strong blue coloration in external reflection, i.e. on the side of the bare face of the glazing, opposite that on which the stack is deposited.

[0020] To obtain such a property, it is necessary that the values ​​of a* and b*, and in particular of b*, in the international system L, a*, b* (typically under a viewing angle of 10° and under illuminant D65), are negative in internal reflection. Values ​​close to 0 are characteristic of a neutral coloration. A neutral or slightly negative value of a* and negative values ​​of b* reflect a blue coloration, the coloration appearing all the more blue as b* is negative.

[0021] To obtain a marked blue color, the value of a* should ideally be between 0 and -5. Values ​​of a* lower than -5 are not desired because they result in a cyan color tending towards green, which is less aesthetically desirable. Similarly, the value of b* should be lower than -10 and as negative as possible for a better rendering of the blue color.

[0022] It is also important that the level of reflection of the glazing on this same side is sufficiently high so that the blue color is sufficiently visible from the outside of the building, even in low sunlight conditions. Thus, RLext values ​​greater than 20%, or even greater than 25%, are expected to bring out the blue color of the glazing in external vision.

[0023] Glazings comprising a single functional layer based on niobium, such as described in application WO01 / 21540 have a relatively low external reflection and / or a positive b* value reflecting a yellow color of the glazing.

[0024] To minimize internal reflection and obtain values ​​of a* and b* close to 0 in internal reflection, patent application WO2009 / 150343 describes a stack comprising several functional layers based on niobium, possibly nitrided, separated by layers of silicon nitride. However, this embodiment does not make it possible to obtain sufficiently high levels of external reflection.

[0025] Publication WO2005 / 105687 describes glazings with a cyan-green color on the exterior face, rather than blue, with values ​​of b*<-5 and a*<-10 (see examples 3 and 4) or whose level of external reflection is limited, in particular less than 20 (see examples 5 to 8).

[0026] A solar-resistant glazing is therefore sought whose stacking allows a marked blue appearance in external reflection. The object of the present invention is to propose such glazing.

[0027] In particular, according to the present invention, it has been found that the insertion of a layer of silicon and zirconium nitride into a solar protection stack whose functional layer is based on niobium makes it possible to obtain the desired properties of the glazing and in particular:

[0028] - an external light reflection RLext (i.e. on the bare face of the substrate opposite that on which the stack of layers is deposited) greater than 20%, and even greater than 25% - a parameter a*, in external reflection, between 0 and -5, - a value of b* less than -10.

[0029] According to the invention, the parameters L, a* and b* are measured according to the CIE LAB criteria, at an angle of 10° and with the illuminant D65.

[0030] Furthermore, the glass articles and glazings according to the invention have solar control properties in accordance with those required in the field, in particular a solar factor g close to and preferably less than 50%, or even less than 40% or even less than or equal to 30%, or even less than or equal to 25% in certain configurations.

[0031] More specifically, the present invention relates to a transparent glass article for solar-protection glazing, comprising at least one clear glass substrate provided on at least one of its faces with a coating consisting of a stack of layers, said coating comprising the following succession of layers, starting from the surface of said substrate: - a first layer based on silicon nitride with a thickness ei of between 55 nm and 90 nm,

[0032] - a layer based on silicon and zirconium nitride with a thickness e2 comprised between 5 nm and 25 nm,

[0033] - a so-called functional layer based on niobium, with a thickness of between 15 nm and 50 nm,

[0034] - a second layer based on silicon nitride with a thickness e3 of between 10 nm and 45 nm,

[0035] in which the stack comprises only one niobium-based layer,

[0036] in which the sum of the thicknesses ei+e2 of the first layer based on silicon nitride and of the layer based on silicon nitride and zirconium is between 60 and 110 nm, preferably between 70 and 100 nm, more preferably between 80 and 90 nm.

[0037] According to particular and preferred embodiments of the present invention, which may be combined with each other where appropriate:

[0038] - The ratio ei / e2 is between 3 and 18, preferably between 4 and 15, preferably still between 6 and 10.

[0039] - The ratio (ei+e2) / e3 is greater than 3 and preferably less than 7.

[0040] - The sum of the thicknesses ei+e2 of the first layer based on silicon nitride and the layer based on silicon nitride and zirconium is between 70 nm and 100 nm, more preferably between 80 nm and 90 nm.

[0041] - The layer based on silicon nitride and zirconium is in direct contact of the niobium-based layer.

[0042] - The niobium-based layer has a thickness of between 20 nm and 40 nm, preferably still between 20 nm and 30 nm.

[0043] - The first layer based on silicon nitride has a thickness of between 65 nm and 90 nm, preferably between 70 nm and 80 nm.

[0044] - The layer based on silicon and zirconium nitride has a thickness of between between 6 nm and 20 nm, more preferably between 7 nm and 15 nm.

[0045] - The second layer based on silicon nitride has a thickness of between 15 nm and 40 nm, preferably between 20 nm and 30 nm.

[0046] - The first layer based on silicon nitride is in contact with the surface of the substrate and preferably is in contact with the layer based on silicon and zirconium nitride.

[0047] - The layer based on silicon nitride and zirconium has an atomic ratio Si / Zr of between 1.5 and 6.0, preferably between 2.0 and 5.5, or even very preferably between 2.5 and 5.0.

[0048] - The niobium-based layer is made up of only metals.

[0049] - The niobium-based layer is not nitrided.

[0050] - The niobium-based layer is at least partially nitrided.

[0051] - The stack comprises, above the silicon nitride-based layer, a protective layer comprising titanium oxide, zirconium oxide or a titanium and zirconium oxide, said layer having a thickness of less than 10 nm, preferably less than 5 nm, for example between 1 and 5 nm.

[0052] - The stack comprises or preferably consists of the succession of following layers, each layer preferably being in direct contact with the next, from the surface of said substrate:

[0053] SiN / SiZrN / Nb / SiN / possibly TiO, ZrO or TiZrO

[0054] in which SiN denotes a layer based on silicon nitride, Nb denotes a layer based on niobium, SiZrN denotes a layer based on silicon nitride and zirconium, TiO denotes a layer comprising a titanium oxide, ZrO denotes a layer comprising a zirconium oxide and TiZrO denotes a layer comprising a titanium and zirconium oxide.

[0055] - The stack does not include functional layers based on Ag, Au, Pt, Cu, Neither stainless steel nor stainless steel.

[0056] - A metallic layer of titanium or a metallic alloy containing titanium is deposited between the niobium-based layer and the second silicon nitride-based layer, said metallic layer being in direct contact with said silicon nitride-based and niobium-based layers.

[0057] - The article is thermally hardened and / or curved.

[0058] - The article presents in internal reflection at least one parameter a* between 0 and - 5, and a parameter b less than -10, in the colorimetric system L, a*, b*, at an angle of 10° and under illuminant D65.

[0059] - The clear glass substrate has a thickness of between 2 mm and 10 mm, preferably between 3 mm and 8 mm, especially 4 mm or 6 mm.

[0060] Throughout the description, thicknesses are physical (geometric) thicknesses, unless otherwise indicated.

[0061] In the layers according to the invention based on niobium, niobium represents at least 50% of the metal atoms present in said layer (in particular apart from the possible presence of heteroatoms such as nitrogen or oxygen), and preferably more than 80% or even more than 90% of the metal atoms of said layers. Other minority metal elements may in particular be present, such as zirconium, titanium, tantalum. By minority is meant that said metal atoms are present in an amount of less than 30%, preferably 20% of the niobium atoms.

[0062] According to a preferred embodiment, the layer only comprises metals, apart from unavoidable impurities.

[0063] Without departing from the scope of the invention, heteroatoms such as nitrogen may however be present in the niobium-based functional layer, although this configuration is less preferred for anti-sun properties. In such an embodiment realization, the atomic ratio N / Nb can vary for example between 0 (excluded) and 1, for example between 0.1 and 0.7.

[0064] Preferably, however, the niobium-based layer comprises less than 5 atomic% of nitrogen, or even the nitrogen is present only in the form of unavoidable impurities.

[0065] The formulation of the layers and in particular the value of x, can be obtained conventionally by XPS photoelectron spectrometry, according to techniques well known in the field of materials.

[0066] The niobium-based layer may further comprise a small amount of oxygen, for example such that the O / Nb atomic ratio is less than 0.2, preferably less than 0.1 or even less than 0.05. According to a preferred embodiment, however, the niobium-based layers do not comprise oxygen other than in the form of unavoidable impurities.

[0067] In the layers according to the invention based on silicon and zirconium nitride, silicon and zirconium together represent more than 80% or even more than 90% of the metal atoms present in said layers, i.e. in particular excluding nitrogen atoms. Based on a SixZryN formulation, the x / y ratio in said layer (atomic ratio Si / Zr) is between 1.5 and 6.0, and preferably is between 2.0 and 5.5, or even between 2.5 and 5.0. More preferably, said layers consist essentially of silicon and zirconium nitride, but may also comprise another metal such as aluminum.Aluminium is used in a well-known manner, in proportions of up to 10 atomic % based on the sum of the elements Si, Zr and Al, or even more and preferably between 1 and 8 atomic % based on the sum of the elements Si, Zr and Al, in silicon targets used for the deposition of layers by cathodic sputtering assisted by a magnetic field (magnetron).

[0068] In the layers according to the invention based on silicon nitride, silicon represents more than 80% or even more than 90% by weight of the metal atoms present in said layers, in particular excluding nitrogen atoms. More preferably, said layers based on silicon nitride consist essentially of silicon nitride, but may also comprise another metal such as aluminium. Aluminium is used in a well-known manner, in proportions of up to 10 atomic%, based on the sum of the elements Si and Al, or even more and preferably between 1 and 8 atomic%, based on the sum of the elements Si Zr and Al, in silicon targets used for the deposition of layers by cathode sputtering assisted by a magnetic field (magnetron).

[0069] The coatings according to the invention are conventionally deposited by deposition techniques of the type of vacuum sputtering assisted by a magnetic field of a cathode. of the material or a precursor of the material to be deposited, often called magnetron sputtering technique in the field. Such a technique is today classically used in particular when the coating to be deposited consists of a more complex stack of successive layers with thicknesses of a few nanometers or a few tens of nanometers.

[0070] The present invention also relates to single glazing or a spandrel-type facade cladding panel incorporating a glass article as previously described.

[0071] According to another embodiment, the glass article according to the invention and as described previously can be incorporated into multiple glazing such as double glazing or even laminated glazing comprising two sheets of glass bonded by a thermoplastic sheet such as PVB.

[0072] The glass article according to the invention can also be incorporated into a side window, a rear window or a roof for an automobile or other vehicle.

[0073] By the terms "underlayer" and "overlayer", reference is made in the present description to the respective position of said layers relative to the functional layer comprising niobium nitride in the stack, said stack being supported by the glass substrate taken as reference.

[0074] In particular, the underlayer is generally the layer in contact with the glass substrate and the overlayer is the outermost layer of the stack, facing away from the substrate.

[0075] The terms "above" or "below", unless otherwise stated, are understood to refer to the surface of the substrate on which the stack is deposited.

[0076] If the application more particularly targeted by the invention is glazing for buildings, it is clear that other applications are conceivable, in particular in vehicle glazing (apart from the windshield where very high light transmission is required), such as side windows, car roofs, rear windows.

[0077] The invention and its advantages are described in more detail below by means of the non-limiting examples below, according to the invention and comparative examples. In all the examples and the description, the thicknesses given are physical.

[0078] All substrates are made of 6 mm thick clear glass of the Planilux® type marketed by Saint-Gobain Glass France.

[0079] All layers are deposited in a known manner by magnetic field-assisted cathode sputtering (often called magnetron).

[0080] In a well-known manner, the different successive layers are deposited in the successive compartments of the cathode sputtering device, each compartment being provided with a specific metal target in Si, SiZr or Nb chosen for the deposition of a specific layer of the stack.

[0081] More specifically, the silicon nitride-based layers are deposited in compartments of the device from a silicon target comprising 8% by mass of aluminum, in a reactive atmosphere containing nitrogen (40% Ar and 60% N2). The silicon nitride-based layers, denoted SiN for convenience, therefore contain a little aluminum.

[0082] The silicon and zirconium nitride-based layers are deposited in a compartment of the device from a metal target consisting of silicon, zirconium and aluminum in the atomic proportions 68 / 27 / 5. The target is sputtered according to conventional techniques in a reactive atmosphere containing nitrogen and argon (45% Ar and 65% N2). The silicon and zirconium nitride layers according to the invention, denoted SiZrN for convenience, therefore contain a little aluminum.

[0083] The metallic Nb layers are obtained by magnetron-assisted sputtering of a metallic niobium target in an argon atmosphere, according to conditions well known in the field. Examples:

[0084] In all the following examples (according to the invention and comparative), the glass substrate was successively covered with a stack of layers comprising a layer of metallic niobium surrounded by layers of silicon nitride, and optionally of silicon nitride and zirconium according to the invention.

[0085] In the examples, the stack therefore comprises the succession of the following layers:

[0086] Glass / SiN / SiZrN / Nb / Si3N4

[0087] The details concerning the constitution and the thicknesses of the layers of the different stacks of examples 1 to 7 are reported in table 1 which follows.

[0088] Examples 8 and 9 correspond to stacks known from the prior art, respectively from WO2005 / 105687 and WO01 / 21540.

[0089] All layers are deposited in a known manner by magnetic field-assisted cathode sputtering (often called magnetron).

[0090] In a well-known manner, the different successive layers are deposited in the successive compartments of the cathode sputtering device, each compartment being provided with a specific metal target in Si, or Nb chosen for the deposition of a specific layer of the stack.

[0091] More precisely, the silicon nitride layers are deposited in a first compartment of the device from a metallic silicon target (doped with 8% by mass of aluminum), in a reactive atmosphere containing nitrogen (40% Ar and 60% N2). The silicon nitride layers, denoted SiN for convenience, therefore contain a little aluminum.

[0092] The Nb layers are obtained by magnetron-assisted sputtering of a metallic niobium target in an argon atmosphere, according to conditions well known in the field.

[0093] The silicon and zirconium nitride layers are deposited from a metal target containing silicon, zirconium and aluminum in the atomic proportions 68 / 27 / 5. The target is sputtered according to conventional techniques in a reactive atmosphere containing nitrogen and argon (45% Ar and 65% N2 by volume). The silicon and zirconium nitride layers according to the invention, denoted SiZrN for convenience, therefore contain a little aluminum.

[0094] The glass articles thus synthesized according to conventional techniques are then heated and tempered according to conventional techniques in the field (heating at 620°C for 10 minutes followed by tempering).

[0095] Table 1 below groups together the information concerning the constitution of the anti-solar stacks according to the examples according to the invention and comparative examples, from the surface of the glass:

[0096] [Tables 1] Thickness ei SiN Thickness e2 SiZrN Thickness layer Nb Thickness e3 SiN Ratio ei / e2 Ratio (ej+e2) / e3 Example 1 75 9 23 22 8.3 3.8 Example 2* 55 29 23 22 1.9 3.8 Example 3* 35 49 23 22 0.7 3.8 Example 4* 15 69 23 22 0.2 3.8 Example 5* 50 9 25 22 5.5 2.7 Example 6* 85 5 28 50 17 1.8 Example 7** 85 - 30 28 - - Example 8*** 10 - 33 27 - -

[0097] Comparisons

[0098] **example 3 of WO2005 / 105687

[0099] ***example 3 of WO01 / 21540

[0100] Example 2 has a thickness e2 greater than 25 nm.

[0101] Examples 3 and 4 have an e / e2 ratio of less than 1.

[0102] Example 5 has a thickness ei less than 55 nm leading to a ratio (ei+e2) / e3 less than 3.

[0103] Example 6 has a thickness e3 greater than 45 nm leading to a ratio (ei+e 2) / e3 less than 3.

[0104] Example 7 is Example 3 of prior publication WO2005 / 105687 and Example 8 is Example 3 of prior publication WO01 / 21540.

[0105] The values ​​of light transmission TL and external light reflection Rext are measured in the range 380 nm to 780 nm according to the methods described in the standard NF EN 410 (2011). This same standard is also used to measure the solar factor g of the substrate with its stack. The colorimetric values ​​in external reflection are measured according to the CIE LAB standard at an angle of 10° and with illuminant D65.

[0106] The results obtained are grouped in Table 2 below, in percentages:

[0107] [Tables 2] tl ^Lext RLext h* ü RLext FS (g) in % Example 1 13 26 -4.2 -13.5 22 Example 2* 14 23 -5.2 -11.2 22 Example 3* 14 23 -5.9 -11.2 22 Example 4* 13 29 -7.8 -14.0 22 Example 5* 15 18 1.4 -9 20 Example 6* 15 38 -7 -7 - Example 7** 13 32 -7.9 -14.3 - Example 8*** 8 44 -2.5 2.8 -

[0108] The results reported in Table 2 above show that the glazing obtained from Example 1 according to the invention has a solar factor of the order of 22%, which guarantees good thermal insulation of the building or the passenger compartment.

[0109] It can be seen from Table 2 that the glazing according to Example 1 according to the invention has a blue color and an external reflection sufficiently high for the blue tint to be visible, even in low sunlight conditions.

[0110] On the contrary, the glazings of comparative examples 2 to 4 have a cyan reflection color which tends towards green, due to a value of a* significantly lower than -5.

[0111] Similarly, comparative examples 5 and 6 show that thicknesses ei and e2 not in accordance with the present invention do not lead to obtaining glazing with a marked blue appearance on the outer face.

[0112] Also, the data reported in the preceding table 2 shows that the glazings of examples 7 and 8 according to the prior art do not make it possible to obtain such glazing.

Claims

Claims

1. Transparent glass article for solar-protection glazing, comprising at least one clear glass substrate provided on at least one of its faces with a coating consisting of a stack of thin layers, said coating comprising the following succession of layers, starting from the surface of said substrate: - a first layer based on silicon nitride with a thickness ei of between 55 nm and 90 nm, - a layer based on silicon nitride and zirconium with a thickness e2 of between 5 nm and 25 nm, - a layer based on niobium, with a thickness of between 15 nm and 50 nm, - a second layer based on silicon nitride with a thickness e3 of between 10 nm and 45 nm, in which the stack comprises only one layer based on niobium, in which the sum of the thicknesses of the first layer based on silicon nitride and of the layer based on silicon nitride and zirconium is between 60 nm and 110 nm.

2. Article according to claim 1 in which the ratio ej e2 is between 3 and 18.

3. Article according to claim 1 or 2 in which the ratio (ei+e2) / e3 is greater than 3 and preferably less than 7.

4. Article according to one of the preceding claims, in which the layer based on silicon and zirconium nitride is directly in contact with the layer based on niobium.

5. Article according to one of the preceding claims, in which the niobium-based layer has a thickness of between 20 nm and 40 nm.

6. Article according to one of the preceding claims, in which the first silicon nitride-based layer has a thickness of between 70 nm and 90 nm, preferably between 60 nm and 85 nm.

7. Article according to one of the preceding claims, in which the layer based on silicon and zirconium nitride has a thickness of between 5 nm and 20 nm.

8. An article according to any preceding claim, wherein the second layer comprising silicon nitride has a thickness between 15 nm and 40 nm, preferably between 20 nm and 35 nm.

9. Article according to one of the preceding claims, in which the first layer based on silicon nitride is in contact with the surface of the substrate and preferably is in contact with the layer based on silicon nitride and zirconium.

10. Article according to one of the preceding claims, in which the layer based on silicon nitride and zirconium has an atomic ratio Si / Zr of between 1.5 and 6.

0.

11. An article according to any preceding claim, wherein the niobium-based layer is non-nitrided.

12. An article according to one of claims 1 to 10, wherein the niobium-based layer is at least partially nitrided.

13. Article according to one of the preceding claims, in which the stack comprises, above the silicon nitride-based layer, a protective layer comprising titanium oxide, zirconium oxide or a titanium and zirconium oxide, said layer preferably having a thickness of less than 10 nm, preferably less than 5 nm.

14. Article according to one of the preceding claims, in which the stack comprises or preferably consists of the succession of the following layers, each layer preferably being in direct contact with the next, starting from the surface of said substrate: SiN / SiZrN / Nb / SiN / optionally TiO, ZrO or TiZrO in which SiN denotes a layer based on silicon nitride, Nb denotes a layer based on niobium, SiZrN denotes a layer based on silicon nitride and zirconium, TiO denotes a layer comprising a titanium oxide, ZrO denotes a layer comprising a zirconium oxide and TiZrO denotes a layer comprising a titanium and zirconium oxide.

15. Article according to one of the preceding claims, characterized in that the stack does not comprise functional layers based on Ag, Au, Pt, Cu, Ni or stainless steel.