FR3112545A1 - Low emissivity material comprising a thick titanium oxide based layer and a zinc tin oxide based layer - Google Patents

Abstract

The invention relates to a material comprising a transparent substrate coated with a stack of layers comprising at least one silver-based functional metallic layer and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that that each functional metal layer is placed between two dielectric coatings. The stack comprises: - a coating based on titanium oxide comprising at least one layer based on titanium oxide located above and in contact with a functional metallic layer based on silver having a thickness greater than 3 nm, - a layer based on zinc oxide and tin located above and in contact with the layer based on titanium oxide.

Description

Low-emissivity material comprising a thick titanium oxide layer and a zinc tin oxide layer

The invention relates to a material comprising a transparent substrate coated with a stack of thin layers comprising a functional metallic layer based on silver. The invention also relates to glazing comprising these materials as well as the use of such materials for manufacturing thermal insulation and/or solar protection glazing.

The silver-based functional metal layers (or silver layers) have advantageous properties of electrical conduction and reflection of infrared radiation (IR), hence their use in so-called "solar control" glazing aimed at reducing the amount of incoming solar energy and/or in so-called “low-emission” glazing aimed at reducing the amount of energy dissipated outwards from a building or vehicle.

These silver layers are deposited between coatings based on dielectric materials generally comprising several dielectric layers (hereinafter “dielectric coatings”) making it possible to adjust the optical properties of the stack. These dielectric layers also make it possible to protect the silver layer from chemical or mechanical attack.

Frequently, such materials must undergo heat treatments, intended to improve the properties of the substrate and/or of the stack of thin layers. For example, in the case of glass substrates, it may involve thermal toughening treatment intended to mechanically reinforce the substrate by creating high compressive stresses on its surface.

The invention relates more particularly to materials comprising a substrate coated with a stack, intended to undergo a heat treatment at high temperature, having a low emissivity or a low resistivity per square. Emissivity and resistivity (or resistance) per square vary proportionately. Therefore, it is often possible to assess the emissivity of a material by evaluating its resistance per square.

The invention is also concerned with obtaining these materials having a low emissivity without significant modification of the absorption following the heat treatment.

Finally, it remains essential that the advantageous properties of emissivity and absorption are obtained without harming:
- mechanical resistance, in particular scratch and brush resistance, preferably before and after heat treatment,
- resistance to hot corrosion, and
- transparency resulting in the absence of blur after heat treatment.

The optical and electrical properties such as the emissivity of the materials depend directly on the quality of the silver layers such as their crystalline state, their homogeneity as well as their environment. “Environment” means the nature of the layers close to the silver layer and the surface roughness of the interfaces with these layers.

High temperature heat treatments such as annealing, bending and/or quenching cause changes within the silver layer.

In addition, heat treatments at high temperature generally make the stacks more sensitive to scratches. On the other hand, when scratches are created on a material before heat treatment, their visibility increases considerably after heat treatment.

To improve the quality of functional metal layers based on silver, it is known to use under the silver layers dielectric coatings comprising dielectric layers with stabilizing function intended to promote wetting and nucleation of the silver layer. . Dielectric layers based on crystallized zinc oxide are notably used for this purpose. Indeed, the zinc oxide deposited by the sputtering process crystallizes without requiring additional heat treatment. The layer based on zinc oxide can therefore serve as an epitaxial growth layer for the silver layer.

Another way to prevent the degradation of the silver layers lies in the choice of the layer located above and in contact with the silver layer. Among the known proposals is the use of so-called blocking layers or dielectric layers based on crystallized zinc oxide. The objective is to protect the functional layers from possible degradation during the deposition of the upper dielectric coating and/or during a heat treatment.

The blocking layers are generally based on a metal chosen from nickel, chromium, titanium, niobium, or an alloy of these various metals. The various metals or alloys mentioned can also be partially oxidized, in particular have an oxygen sub-stoichiometry (for example TiOx or NiCrOx).

These blocking layers are very thin, normally less than 2 nm thick, and are susceptible at these thicknesses to being partially oxidized during heat treatment. In general, these blocking layers are sacrificial layers, capable of capturing oxygen coming from the atmosphere or from the substrate, thus avoiding the oxidation of the silver layer.

The use of these thin blocking layers does not make it possible to obtain sufficiently high-performance materials having in particular a sufficiently low resistivity.

Good results in terms of resistivity have been obtained so far with a material that does not include a blocking layer. The silver layer is located in contact with two layers of crystallized zinc oxide located respectively above and below the silver layer. Materials comprising the sequence ZnO/Ag/ZnO are qualified as reference material in the present application.

This solution consisting in using only layers based on crystallized zinc oxide below and below the silver makes it possible to obtain advantageous resistivity values. However, the following disadvantages remain:
- appearance of blur after heat treatment,
- appearance of corrosion spots after heat treatment.

The applicant has discovered that the use of a thick layer of titanium oxide located above and in contact with the silver-based functional layer, in a particular stack, makes it possible to overcome these drawbacks.

Surprisingly, this solution also makes it possible to further reduce the resistivity after heat treatment compared with a reference material.

This solution makes it possible to obtain, after heat treatment, advantageous resistivity values, without blurring or the appearance of corrosion points. A significant improvement in the mechanical properties of scratch resistance is also observed following the heat treatment, resulting in:
- less visible scratches and
- if present, the absence of hot corrosion of these existing scratches.

However, the mere presence of a thick layer of titanium oxide does not allow:
- to limit the increase in absorption before heat treatment,
- to obtain satisfactory mechanical resistance to the brush resistance test before and after heat treatment.

The applicant has therefore sought how to improve these properties. He discovered surprisingly that the use of a layer based on titanium oxide associated with a layer based on zinc oxide and particular tin made it possible to overcome these drawbacks but also to bring additional other advantageous properties.

The invention therefore relates to a material comprising a transparent substrate coated with a stack of layers comprising at least one functional metallic layer based on silver and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so as to that each functional metal layer is placed between two dielectric coatings, the stack comprises:
- a coating based on titanium oxide comprising at least one layer based on titanium oxide located above and in contact with a functional metallic layer based on silver having a thickness greater than 3 nm,
- a layer based on zinc oxide and tin comprising at least 20% by mass of tin relative to the total mass of zinc and tin, located above and in contact with the layer based on titanium oxide.

According to a particularly advantageous embodiment, the coating based on titanium oxide is a coating comprising an oxidation gradient (hereinafter oxidation gradient coating) located above and in contact with a functional metal layer at silver basis. The part of the oxidation gradient coating in contact with the functional layer is less oxidized than the part of this coating further from the functional layer.

This embodiment combining a coating based on titanium oxide with an oxidation gradient and a layer based on zinc and tin oxide makes it possible to obtain the best performance.

The solution of the invention makes it possible to obtain, compared to the reference material:
- an improvement in the resistivity with the obtaining of a square resistance gain of at least 5%, or even 10% or more, for certain structures of the invention, both before and after heat treatment,
- an improvement in the mechanical properties of brush resistance before and after heat treatment.

In certain embodiments, the improvement in resistivity is obtained without an increase in absorption, before and after heat treatment. This means that, in certain embodiments, the improvement in resistivity is obtained without an increase in absorption, before and after heat treatment.

The solution of the invention also makes it possible to obtain these advantageous properties, without blurring or the appearance of corrosion spots. A significant improvement in the mechanical properties of scratch resistance is also observed following the heat treatment, resulting in:
- less visible scratches and
- if present, the absence of hot corrosion of these existing scratches.

The invention also makes it possible to obtain an improvement in the solar factor. This improvement is partly linked to the presence of a high-index layer in contact with the silver layer. The effect on the solar factor makes it possible to obtain:
- for a given thickness of agent, a higher solar factor, or
- for a given emissivity, a lower thickness for the silver layer.

The invention therefore allows the development of a material comprising a substrate coated with a stack comprising at least one functional layer based on silver having, following a heat treatment of the bending, quenching or annealing type, with respect to a reference material with the same silver layer thickness:
- low emissivity without increased absorption,
- higher solar factor and light transmission,
- low visibility of scratches (if present) following heat treatment,
- good resistance to the brush test, and
- significantly improved resistance to hot corrosion.

The invention therefore allows the development of a material comprising a substrate coated with a stack comprising at least one functional layer based on silver having, before or without heat treatment:
- low emissivity without increased absorption and
- good resistance to the brush test.

The solution of the invention is particularly suitable in the case of stacks with several functional layers based on silver, in particular stacks with two or three functional layers which are particularly fragile from the point of view of scratches.

The present invention is also particularly suitable in the case of stacks with a single functional layer based on silver intended for applications where the stacks are highly subject to hot corrosion.

The invention also relates to:
- a glazing comprising a material according to the invention,
- a glazing comprising a material according to the invention mounted on a vehicle or on a building, and
- the process for preparing a material or a glazing according to the invention,
- the use of a glazing according to the invention as solar control and/or low emissive glazing for the building or the vehicles,
- A building, a vehicle or a device comprising a glazing according to the invention.

Throughout the description, the substrate according to the invention is considered laid horizontally. The stack of thin layers is deposited above the substrate. The meaning of the expressions “above” and “below” and “lower” and “higher” should be considered in relation to this orientation. In the absence of specific stipulation, the expressions “above” and “below” do not necessarily mean that two layers and/or coatings are arranged in contact with one another. When it is specified that a layer is deposited "in contact" with another layer or a coating, this means that there cannot be one (or more) interposed layer(s) between these two layers (or layer and coating).

All the luminous characteristics described are obtained according to the principles and methods of the European standard EN 410 relating to the determination of the luminous and solar characteristics of the glazing used in glass for construction.

Sunlight entering a building is considered to flow from the exterior to the interior.

According to the invention, the luminous characteristics are measured according to the illuminant D65 at 2° perpendicular to the material mounted in a double glazing:
- TL corresponds to the light transmission in the visible in %,
- Rext corresponds to the external light reflection in the visible in %, observer outside space side,
- Rint corresponds to the interior light reflection in the visible in %, observer on the interior space side,
- a*T and b*T correspond to the colors in transmission a* and b* in the L*a*b* system,
- a*Rext and b*Rext correspond to the colors in reflection a* and b* in the L*a*b* system, observer on the outer space side,
- a*Rint and b*Rint correspond to the colors in reflection a* and b* in the L*a*b* system, observer on the interior space side.

The preferred characteristics which appear in the remainder of the description are applicable both to the material according to the invention and, where applicable, to the glazing or to the method according to the invention.

The material, that is to say the transparent substrate coated with the stack, is intended to undergo heat treatment at high temperature. Therefore, the stack and the substrate have preferably been subjected to a heat treatment at a high temperature such as quenching, annealing or bending.

The stack is deposited by cathode sputtering assisted by a magnetic field (magnetron process). According to this advantageous embodiment, all the layers of the stack are deposited by cathodic sputtering assisted by a magnetic field.

Unless otherwise stated, the thicknesses referred to in this document are physical thicknesses and the layers are thin layers. By thin layer is meant a layer having a thickness of between 0.1 nm and 100 micrometers.

The coating based on titanium oxide can comprise at least one layer based on titanium oxide. In certain embodiment, the coating comprises several layers based on titanium oxide.

The titanium oxide-based coating has a thickness:
- greater than 3 nm, greater than 4 nm, greater than or equal to 5 nm,
- less than or equal to 30 nm, less than or equal to 25 nm, less than or equal to 20 nm, less than or equal to 15 nm, less than or equal to 10 nm, less than or equal to 8 nm.

The layers based on titanium oxide comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 95.0%, at least 96.5% and better still at least 98.0 % by mass of titanium relative to the mass of all the elements constituting the layer based on titanium oxide other than oxygen.

The layers based on titanium oxide can include or consist of elements other than titanium and oxygen. These elements can be chosen from silicon, chromium and zirconium. Preferably, the elements are chosen from zirconium.

Preferably, the layer based on titanium oxide comprises at most 35%, at most 20% or at most 10% by mass of elements other than titanium relative to the mass of all the elements constituting the layer based on titanium oxide other than oxygen.

The layers based on titanium oxide can have a thickness:
- greater than or equal to 2 nm, greater than or equal to 3 nm, greater than or equal to 4 nm, greater than or equal to 5 nm, and/or
- less than or equal to 30 nm, less than or equal to 25 nm, less than or equal to 20 nm, less than or equal to 15 nm, less than or equal to 10 nm, less than or equal to 8 nm, less than or equal to 4 nm.

The layers based on titanium oxide can be obtained:
- by sputtering,
- from a metallic titanium target or a ceramic target based on titanium oxide, preferably substoichiometric.

When the titanium oxide-based layer is obtained from a metal target, the deposition atmosphere includes significant proportions of oxygen.

The layers based on titanium oxide are preferably obtained from a ceramic target of titanium oxide, preferably under stoichiometric in oxygen, in an atmosphere comprising oxygen or without oxygen. The quantity of oxygen in the deposition atmosphere can be adapted according to the desired properties.

According to the preferred embodiment, a layer based on titanium oxide is deposited from a ceramic target, in particular substoichiometric, in a controlled atmosphere comprising oxygen.

The layer based on titanium oxide can be deposited from a ceramic target of TiO _x with x between 1.5 and 2.

The layer based on titanium oxide can be deposited from a ceramic target of sub-stoichiometric TiO _x , where x is a number different from the stoichiometry of the titanium oxide TiO ₂ , that is to say different from 2 and preferably less than 2, in particular between 0.75 times and 0.99 times the normal stoichiometry of the oxide. TiOx may in particular be such that 1.5<x<1.98 or 1.5<x<1.7, or even 1.7<x<1.95.

The layer based on titanium oxide can be deposited in an atmosphere not containing oxygen or in a controlled atmosphere comprising oxygen.

According to the invention, the term “controlled atmosphere comprising oxygen” means an atmosphere comprising an optimized quantity of oxygen to obtain, after heat treatment, a gain in resistivity without harming the absorption on the one hand, and the brush resistance before and after annealing (EBT), on the other hand.

The deposition atmosphere comprises a mixture of noble gases (He, Ne, Xe, Ar, Kr) and oxygen. The noble gas is preferably argon.

The following parameters are used to define the conditions for sputtering deposition:
- the deposition pressure,
- the composition of the gases in volume flow (unit sccm "standard cubic centimeter per minute").

The controlled atmosphere making it possible to obtain the advantageous effects of the invention was obtained in particular with the following parameters:
- the pressure in the deposition chamber is between 1 and 15 µbar, preferably 2 and 10 µbar or 2 and 8 µbar,
- the deposition atmosphere comprises a mixture of argon and oxygen.

The controlled atmosphere making it possible to obtain the advantageous effects of the invention was obtained with a percentage by volume flow of oxygen of between 0 and 10%, between 0.1 and 10%, between 0.1 and 5%, between 0.1 and 4%, between 0.5 and 3%, between 1 and 2.5% or between 1.5 and 2%.

The maximum oxygen threshold may vary to some extent depending on, for example:
- the nature of the TiOx target, in particular its oxygen sub-stoichiometry or
- power.

Indeed, if a low deposition power is used, the volume flow quantities of oxygen that can be used during the deposition will be lower because the TiOx is deposited more slowly and is therefore more likely to oxidize.

A person skilled in the art is able to define a satisfactory controlled atmosphere by varying these parameters to some extent. A person skilled in the art is in particular perfectly able to determine the power to be applied to the target and the volume flow rates of oxygen and noble gases.

For this, for a given deposition pressure, the person skilled in the art is able to make increasing additions of oxygen in order to determine the range of proportion of oxygen which makes it possible to lower the resistivity after heat treatment without harming the 'absorption.

Preferably, the coating based on titanium oxide comprises a first layer based on titanium oxide in contact with the functional layer based on silver deposited from a ceramic target, in particular under stoichiometric, in an atmosphere oxidant whose percentage by volume flow of oxygen represents between 0 and 5%, between 0 and 4%, between 0.1 and 4%, between 0.5 and 4%, between 0 and 3%, between 0.1 and 3%, between 0.5 and 3%, between 0.1 and 2.5% or between 0.5 and 2%.

According to an advantageous embodiment, the coating based on titanium oxide is a coating comprising an oxidation gradient based on titanium oxide located above and in contact with a functional metallic layer based on silver , the part of the oxidation gradient coating in contact with the functional layer is less oxidized than the part of this coating further from the functional layer.

According to the invention, the titanium oxide coating is described as it is deposited, that is to say before any heat treatment or before any long storage. Indeed, a heat treatment at high temperature or a long storage can generate modifications within layers or coating. These modifications may in particular correspond to a rearrangement of the oxygen atoms within the coating, making it more difficult to observe the gradient.

The oxidation gradient coating may include:
- a layer of titanium oxide comprising an oxygen gradient,
- at least two layers of titanium oxide comprising different proportions of oxygen.

The layers based on titanium oxide are preferably deposited from a ceramic target of titanium oxide under the conditions defined above.

The oxidation gradient coating may comprise at least one layer based on titanium oxide deposited from a ceramic target, in particular substoichiometric, in a controlled atmosphere comprising oxygen, preferably in a controlled atmosphere comprising oxygen. The layer based on titanium oxide can be deposited with a percentage of oxygen in volume flow representing between 0.1 and 10%.

The oxidation gradient coating may comprise at least two layers of titanium oxide each comprising different proportions of oxygen, that is to say different degrees of oxidation.

In this case, the coating is obtained by depositing at least two consecutive layers based on titanium oxide. This deposition in several stages makes it possible to obtain mainly in the coating a layer of titanium oxide with a large quantity of oxygen, while protecting the functional layer based on silver from a first layer of titanium oxide weakly oxidized. The absorption of the stack before heat treatment is then greatly reduced.

The oxidation gradient coating can also comprise a first layer deposited from a ceramic target, in particular substoichiometric, in an oxygen-free atmosphere.

The oxidation gradient coating may comprise a first layer based on titanium oxide deposited from a ceramic target, in particular substoichiometric, in an oxidizing atmosphere whose percentage by volume flow of oxygen represents between 0 and 5 %, between 0 and 4%, between 0.1 and 4%, between 0.5 and 4%, between 0 and 3%, between 0.1 and 3%, between 0.5 and 3%, between 0.1 and 2.5% or between 0.5 and 2%.

The amount of oxygen in the first layer based on titanium oxide must be relatively low so as not to degrade the functional layer based on silver. For this, we can use a first layer deposited from a ceramic target, in particular under stoichiometric, in an atmosphere without oxygen or with very little oxygen. However, using a little oxygen contributes to a better resistance to the brush test without inducing too great a penalty in absorption, especially before heat treatment.

The thickness of the first layer based on titanium oxide can be as thin as that of a standard blocking layer (<1nm), as long as the functional layer based on silver does not prove to be degraded by the oxygen present during the deposition of the next layer based on titanium oxide, deposited with more oxygen than the first.

The first layer has a thickness between 0.2 and 4 nm. The first layer can have a thickness of less than 3 nm, less than 2 nm, less than 1 nm or less than 0.5 nm.

The oxidation gradient coating comprises a second layer based on titanium oxide deposited from a ceramic target, in particular substoichiometric, in an atmosphere comprising higher proportions of oxygen than that used for the first layer.

The second layer based on titanium oxide can be deposited from a metal target or a ceramic target.

The second layer based on titanium oxide can be deposited from a ceramic target in particular under stoichiometric, in an oxidizing atmosphere whose percentage of oxygen in volume flow represents between 1 and 10%, between 1.5 and 8 %, between 2 and 5%.

The second layer based on titanium oxide has a thickness between 0.2 and 30 nm, between 2 and 20 nm or between 5 and 15 nm.

The second layer based on titanium oxide can have a thickness:
- greater than 0.5 nm, greater than 1 nm, greater than 2 nm, greater than 3 nm, greater than 4 nm, greater than 5 nm,
- less than 30 nm, less than 20 nm, less than 15 nm or less than 10 nm.

The oxidation gradient coating can also comprise a single layer of titanium oxide comprising an oxygen gradient.

A coating based on titanium oxide comprising a single layer with an oxygen gradient can be obtained:
- by sputtering,
- in an atmosphere comprising a mixture of neutral gas and oxygen, by gradually increasing the flow rates of oxygen present in the atmosphere,
- from a metallic titanium target or a ceramic target based on titanium oxide, preferably substoichiometric.

In this case, the volume flow rate of oxygen in the deposition atmosphere is gradually increased as the layer based on titanium oxide is deposited. The part of the oxidation gradient coating in contact with the functional layer is less oxidized than the part of this coating further from the functional layer.

Typically, when the target is a ceramic target under stoichiometric in oxygen, the proportions of oxygen in the deposition atmosphere can vary from 0% to 10%, preferably from 0 to 5%.

According to the invention, the stack comprises at least one functional metallic layer based on silver.

The silver-based functional metallic layer, before or after heat treatment, comprises at least 95.0%, preferably at least 96.5% and better still at least 98.0% by mass of silver with respect to the mass of the functional layer.

Preferably, the silver-based functional metal layer before heat treatment comprises less than 1.0% by mass of metals other than silver relative to the mass of the silver-based functional metal layer.

The thickness of the silver-based functional layer is between 5 to 25 nm, 8 to 20 nm or 8 to 15 nm.

The stack of thin layers comprises at least one functional layer and at least two dielectric coatings comprising at least one dielectric layer, so that each functional layer is placed between two dielectric coatings.

The stack of thin layers can comprise at least two metallic functional layers based on silver and at least three dielectric coatings comprising at least one dielectric layer, so that each functional layer is placed between two dielectric coatings.

The stack of thin layers can comprise at least three functional layers and at least four dielectric coatings comprising at least one dielectric layer, so that each functional layer is placed between two dielectric coatings.

The stack is located on at least one of the faces of the transparent substrate.

By "dielectric coating" within the meaning of the present invention, it should be understood that there may be a single layer or several layers of different materials inside the coating. A “dielectric coating” according to the invention mainly comprises dielectric layers. However, according to the invention, these coatings can also comprise layers of another nature, in particular absorbent layers or metallic layers other than functional layers based on silver. For example, the coating farthest from the substrate may comprise a protective layer deposited in metallic form.

It is considered that a "same" dielectric coating is located:
- between the substrate and the first functional layer,
- between each functional metal layer based on silver,
- above the last functional layer (furthest from the substrate).

By "dielectric layer" within the meaning of the present invention, it should be understood that from the point of view of its nature, the material is "non-metallic", that is to say is not a metal. In the context of the invention, this term designates a material having an n/k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5. n designates the index of real refraction of the material at a given wavelength and k represents the imaginary part of the refractive index at a given wavelength; the ratio n/k being calculated at a given wavelength identical for n and for k.

The thickness of a dielectric coating corresponds to the sum of the thicknesses of the layers constituting it.

According to the invention, the layers based on titanium oxide form part of a dielectric coating. This means that when determining the thickness of a dielectric coating, the thickness of these layers is taken into consideration.

Preferably, the dielectric coatings have a thickness greater than 10 nm, greater than 15 nm, between 15 and 200 nm, between 15 and 100 nm or between 15 and 70 nm.

The dielectric layers of the coatings have the following characteristics alone or in combination:
- they are deposited by cathodic sputtering assisted by a magnetic field,
- they are chosen from oxides or nitrides of one or more elements chosen from titanium, silicon, aluminium, zirconium, tin and zinc,
- they have a thickness greater than 2 nm, preferably between 2 and 100 nm, between 5 and 50 nm or between 5 and 30 nm.

Some dielectric layers have a barrier function. By dielectric layers with barrier function (hereinafter barrier layer) is meant a layer made of a material capable of forming a barrier to the diffusion of oxygen and water at high temperature, coming from the ambient atmosphere or from the substrate. transparent, towards the functional layer.

Such dielectric layers are chosen from:
- the layers comprising silicon and/or aluminum and/or zirconium and are chosen for example from oxides such as SiO2, nitrides such as silicon nitride Si3N4 and aluminum nitrides AIN, and oxynitrides SiOxNy, optionally doped with at least one other element,
- layers based on zinc and tin oxide,
- layers based on titanium oxide.

The material comprises a layer based on zinc oxide and tin comprising at least 20% by mass of tin relative to the total mass of zinc and tin, located above and in contact with the layer at titanium oxide base.

The layer based on zinc oxide and tin comprises by mass of tin relative to the total mass of zinc and tin:
- at least 30%, at least 40%, at least 45%, at least 50% or at least 55%,
- at most 70%, at most 65% or at most 60% by mass of zinc.

The layer based on zinc oxide and tin has a thickness:
- greater than 5 nm, greater than 10 nm, greater than 15 nm, greater than 18 nm,
- less than 40 nm, less than 30 nm, less than 25 nm.

The stack may comprise at least one layer comprising silicon. Each dielectric coating may include at least one layer comprising silicon.

Layers comprising silicon are extremely stable to heat treatments. For example, no migration of the constituent elements is observed. Therefore, these elements are not likely to alter the silver layer. Layers comprising silicon therefore also contribute to the non-alteration of the silver layers and therefore to obtaining a low emissivity after heat treatment.

The layers comprising silicon can be chosen from layers based on oxide, based on nitride or based on silicon oxynitride such as layers based on silicon oxide, layers based on silicon nitride and layers based on silicon oxynitride.

The layers comprising silicon can comprise or consist of elements other than silicon, oxygen and nitrogen. These elements can be chosen from among aluminum, boron, titanium, and zirconium.

The layers comprising silicon can comprise at least 50%, at least 60%, at least 65%, at least 70% at least 75.0%, at least 80% or at least 90% by mass of silicon with respect to the mass of all the elements constituting the layer comprising silicon other than nitrogen and oxygen.

Preferably, the layer comprising silicon comprises at most 35%, at most 20% or at most 10% by mass of elements other than silicon relative to the mass of all the elements constituting the layer comprising silicon other than oxygen and nitrogen.

According to one embodiment, the layers comprising silicon comprise less than 35%, less than 30%, less than 20%, less than 10%, less than 5% or less than 1% by mass of zirconium with respect to the mass of all the elements constituting the layer based on silicon oxide other than oxygen and nitrogen.

The layer comprising silicon may comprise at least 2%, at least 5.0% or at least 8% by mass of aluminum relative to the mass of all the elements constituting the layer based on silicon oxide other than oxygen and nitrogen.

The amounts of oxygen and nitrogen in a layer are determined in atomic percentages relative to the total amounts of oxygen and nitrogen in the layer under consideration.

According to the invention:
- layers based on silicon oxide mainly contain oxygen and very little nitrogen,
- the layers based on silicon nitride essentially comprise nitrogen and very little oxygen,
- the layers based on silicon oxynitride comprise a mixture of oxygen and nitrogen.

Silicon oxide based layers include at least 90% atomic percent oxygen relative to the oxygen and nitrogen in the silicon oxide based layer.

The silicon nitride based layers include at least 90% atomic percent nitrogen relative to the oxygen and nitrogen in the silicon oxide based layer.

The layers based on silicon oxynitride include 10 to 90% (limits excluded) in atomic percentage of nitrogen relative to the oxygen and nitrogen in the layer based on silicon oxide.

Preferably, the layers based on silicon oxide are characterized by a refractive index at 550 nm, less than or equal to 1.55.

Preferably, the layers based on silicon nitride are characterized by a refractive index at 550 nm, greater than or equal to 1.95.

Preferably, the layers based on silicon oxynitride are characterized by a refractive index at 550 nm intermediate between a layer of non-nitrided oxide and a layer of non-oxidized nitride. The layers based on silicon oxynitride preferably have a refractive index at 550 nm greater than 1.55, 1.60 or 1.70 or between 1.55 and 1.95, 1.60 and 2.00 , 1.70 and 2.00 or 1.70 and 1.90.

These refractive indices may vary to some extent depending on the deposition conditions. Indeed, by playing on certain parameters such as the pressure or the presence of dopants, it is possible to obtain more or less dense layers and therefore a variation in refractive index.

The layers comprising silicon can be layers of silicon and aluminum nitride and optionally of zirconium. These layers of silicon and aluminum and/or zirconium nitride may also comprise, by weight relative to the weight of silicon, aluminum and zirconium:
- 50 to 98%, 60 to 90%, 60 to 70% by weight of silicon,
- 2 to 10% by weight of aluminium,
- 0 to 30%, 10 to 30% or 15 to 27% by weight of zirconium.

The sum of the thicknesses of all the layers comprising silicon in each dielectric coating is greater than or equal to 5 nm, greater than or equal to 10 nm, or even greater than or equal to 15 nm.

These layers comprising silicon have, in increasing order of preference, a thickness:
- less than or equal to 40 nm and/or
- greater than or equal to 5 nm, greater than or equal to 10 nm or greater than or equal to 15 nm.

The dielectric coatings can comprise other layers than these layers comprising silicon.

Preferably, the sum of the thicknesses of all the layers comprising silicon in the dielectric coating located between the substrate and the first layer of silver is greater than 35%, greater than 50%, greater than 60%, greater than 70%, greater than to 75% of the total thickness of the dielectric coating.

Preferably, the sum of the thicknesses of all the layers comprising silicon based on silicon nitride in the dielectric coating located between the substrate and the first silver layer is greater than 35%, greater than 50%, greater than 60% greater than 70%, greater than 75% of the total thickness of the dielectric coating.

Preferably, the sum of the thicknesses of all the layers comprising silicon in each dielectric coating located above the first silver-based functional metal layer can be greater than 35%, greater than 50%, greater than 60% greater at 70%, greater than 75% of the total thickness of the dielectric coating.

Preferably, the sum of the thicknesses of all the layers comprising silicon based on silicon nitride in each dielectric coating located above the first functional metal layer based on silver can be greater than 35%, greater than 50% , greater than 60% greater than 70%, greater than 75% of the total thickness of the dielectric coating.

Preferably, the sum of the thicknesses of all the layers comprising silicon in each dielectric coating may be greater than 35%, greater than 50%, greater than 60%, greater than 70%, greater than 75% of the total thickness of the dielectric coating.

Preferably, the stack does not include a metallic blocking layer or one based on titanium oxide below and in contact with the functional metallic layer based on silver. In this case, the silver-based functional metallic layer is located above and in contact with a dielectric layer of the dielectric coating. Preferably, this dielectric layer is a stabilizing or wetting layer made of a material capable of stabilizing the interface with the functional layer. These layers are generally based on zinc oxide.

The metallic functional layer can therefore be deposited above and in contact with a layer based on zinc oxide.

The layers based on zinc oxide, can comprise, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% by mass of zinc relative to the total mass of all the elements constituting the layer based on zinc oxide excluding oxygen and 'nitrogen.

To be correctly crystallized by sputtering deposition, the layers based on zinc oxide advantageously comprise at least 80%, even at least 90% by mass of zinc relative to the total mass of all the elements constituting the layer based zinc oxide excluding oxygen and nitrogen.

The layers based on zinc oxide can comprise one or more elements chosen from among aluminum, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin and hafnium, preferably aluminum.

Layers based on zinc oxide can optionally be doped with at least one other element, such as aluminum.

A priori, the layer based on zinc oxide is not nitrided, however traces may exist.

The layer based on zinc oxide comprises, in increasing order of preference, at least 80%, at least 90%, at least 95%, at least 98%, at least 100%, by mass of oxygen with respect to the total mass of oxygen and nitrogen.

Preferably, the dielectric coating located directly below the silver-based functional metal layer comprises at least one crystallized dielectric layer, in particular based on zinc oxide, optionally doped with at least one other element, such as aluminum. The metallic functional layer is deposited above and in contact with a layer based on zinc oxide.

The zinc oxide-based layer is deposited from a ceramic target, with or without oxygen or from a metal target.

The dielectric coatings located between the substrate and the first silver layer can only consist of layers comprising silicon and layers based on zinc oxide.

In all stacks, the dielectric coating closest to the substrate is called the bottom coating and the dielectric coating furthest from the substrate is called the top coating. Stacks with more than one silver layer also include intermediate dielectric coatings located between the bottom and top coating.

Preferably, the lower or intermediate coatings comprise a crystallized dielectric layer based on zinc oxide located directly in contact with the metallic layer based on silver.

The zinc oxide layers have a thickness:
- at least 1.0 nm, at least 2.0 nm, at least 3.0 nm, at least 4.0 nm, at least 5.0 nm, at least 6.0 nm and/or
- at most 25 nm, at most 10 nm, at most 8.0 nm.

The sum of the thicknesses of all the oxide-based layers present in the dielectric coating located below the first functional metal layer may be less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, less than 25% of the total thickness of the dielectric coating.

The sum of the thicknesses of all the oxide-based layers present in each dielectric coating located above the first functional metal layer can be less than 70%, less than 60%, less than 50%, less than 40% at 30%, less than 25% of the total thickness of the dielectric coating.

The stack of thin layers can optionally include a protective layer. The protective layer is preferably the last layer of the stack, that is to say the layer farthest from the coated substrate of the stack (before heat treatment). These layers generally have a thickness of between 0.5 and 10 nm, between 1 and 5 nm, between 1 and 3 nm or between 1 and 2.5 nm. This protective layer can be chosen from among a layer of titanium, zirconium, hafnium, silicon, zinc and/or tin, this or these metals being in metallic, oxidized or nitrided form.

According to one embodiment, the protective layer is based on zirconium oxide and/or titanium, preferably based on zirconium oxide, titanium oxide or titanium oxide and zirconium.

When determining the thickness of a dielectric coating, the thickness of the protective layer is taken into account.

The material of the invention may comprise:
- a layer comprising silicon, preferably based on silicon nitride,
- a layer based on zinc oxide,
- a silver-based layer,
- a coating based on titanium oxide,
- a layer based on zinc and tin oxide,
- a layer comprising silicon, preferably based on silicon nitride,
- possibly a protective layer.

The substrate coated with the stack or the stack only can be intended to undergo a heat treatment. However, the present invention also relates to the unheat-treated coated substrate.

The materials of the invention can be used both in untempered version and in tempered version.

The stack may not have undergone heat treatment at a temperature above 500°C, preferably 300°C.

The stack may have undergone a heat treatment at a temperature above 300°C, preferably 500°C.

The heat treatments are chosen from annealing, for example by rapid thermal annealing (“Rapid Thermal Process”) such as laser or flash lamp annealing, quenching and/or bending. Rapid thermal annealing is for example described in application WO2008/096089. It is also possible to combine heat treatments. For example, it is possible to perform rapid thermal annealing followed by quenching.

The heat treatment temperature (at the level of the stack) is greater than 300°C, preferably greater than 400°C, and better still greater than 500°C.

The coated substrate of the stack can be bent or tempered glass.

The transparent substrates according to the invention are preferably made of a rigid mineral material, such as glass, or organic based on polymers (or polymer).

The organic transparent substrates according to the invention can also be made of polymer, rigid or flexible. Examples of polymers suitable according to the invention include, in particular:
- polyethylene,
- polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN);
- polyacrylates such as polymethyl methacrylate (PMMA);
- polycarbonates;
- polyurethanes;
- polyamides;
- polyimides;
- fluorinated polymers such as fluoroesters such as ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluorethylene (PCTFE), ethylene chlorotrifluorethylene (ECTFE), fluorinated ethylene-propylene copolymers (FEP);
- photocrosslinkable and/or photopolymerizable resins, such as thiolene, polyurethane, urethane-acrylate, polyester-acrylate and
- polythiourethanes.

The substrate is preferably a glass or glass-ceramic sheet.

The substrate is preferably transparent, colorless (it is then a clear or extra-clear glass) or colored, for example blue, gray or bronze. The glass is preferably of the silico-sodo-lime type, but it can also be of borosilicate or alumino-borosilicate type glass.

According to a preferred embodiment, the substrate is made of glass, in particular silico-sodo-lime or of polymeric organic material.

The substrate advantageously has at least one dimension greater than or equal to 1 m, or even 2 m and even 3 m. The thickness of the substrate generally varies between 0.5 mm and 19 mm, preferably between 0.7 and 9 mm, in particular between 2 and 8 mm, or even between 4 and 6 mm. The substrate can be flat or curved, even flexible.

The invention also relates to a glazing comprising at least one material according to the invention. The invention relates to glazing which may be in the form of monolithic, laminated and/or multiple glazing, in particular double glazing or triple glazing.

Monolithic glazing has 2 faces, face 1 is outside the building and therefore constitutes the outer wall of the glazing, face 2 is inside the building and therefore constitutes the inner wall of the glazing.

A multiple glazing unit comprises at least one material according to the invention and at least one additional substrate, the material and the additional substrate are separated by at least one spacer gas layer. The glazing creates a separation between an exterior space and an interior space.

Double glazing has 4 faces, face 1 is outside the building and therefore constitutes the outer wall of the glazing, face 4 is inside the building and therefore constitutes the inner wall of the glazing, faces 2 and 3 being inside the double glazing.

A laminated glazing comprises at least one structure of the first substrate/sheet(s)/second substrate type. The polymer sheet may in particular be based on polyvinyl butyral PVB, ethylene vinyl acetate EVA, polyethylene terephthalate PET, polyvinyl chloride PVC. The stack of thin layers is positioned on at least one of the faces of one of the substrates.

These glazings can be mounted on a building or a vehicle.

The following examples illustrate the invention.

Examples
I. Preparation of substrates : Stacks, deposit conditions you
Stacks of thin layers defined below are deposited on clear soda-lime glass substrates with a thickness of 2 or 4 mm. In the examples of the invention:
- the functional layers are layers of silver (Ag),
- the dielectric layers are based on silicon nitride, doped with aluminum (Si₃NOT₄: Al), zinc and tin oxide and zinc oxide (ZnO).
TiOx titanium oxide layers are deposited from a TiOx ceramic target with or without oxygen in the deposition atmosphere.
The deposition conditions of the layers, which were deposited by sputtering (so-called "magnetron cathodic" sputtering), are summarized in Table 1.

Materials Composition target Pressure Power Gas sccm Ar _O2 # ₂ Ar/O ₂ (90/10) ZnO ZnO:Al 2%wt ceramic 2 µbar 1300W 40 2 - - TiOx_0% TiOx ceramic 2 µbar 2000W 30 0 - - TiOx_1.7% TiOx ceramic 2 µbar 2000W 20 0 - 4 TiOx_3.3% TiOx ceramic 2 µbar 2000W 20 0 - 10 TiOx_5% TiOx ceramic 2 µbar 2000W 20 0 - 20 SnZnO Sn:Zn 60/40% metallic 2 µbar 1500W 15 38 SnZnO* Sn:Zn 60/40% metallic 2 µbar 500W 10 19 Ag Ag metallic 8 µbar 210W 80 - - - Ag* Ag metallic 8 µbar 210W 20 - - - Si3N4 Si:Al 8%wt metallic 2 µbar 2000W 18 - 24 - SiZrN Si:Zr 27%wt metallic 2 µbar 1000W 15 - 15 -

%wt: % by weight

Tables 2, 3 and 4 below list the materials and the physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating which constitutes the stacks according to their positions with respect to the carrier substrate of the stack .

Layers Ref.0 Ref.1 Ref.2 Emp.1-1 TiOx 2 2 2 2 If ₃ N ₄ 30 30 30 10 SnZnOx* - 20 ZnO 5 - - - TiOx: 5% O2
TiOx: 1.7% O2
TiOx: 0% O2 -
-
- -
5
- 3
-
2 -
5
- Ag 12 12 12 12 ZnO 5 5 5 5 If ₃ N ₄ 20 20 20 20 Glass (4mm)

Layers Emp.2-0 Emp.2-1 Emp.2-2 Emp.2-3 TiOx 2 2 2 2 If ₃ N ₄ 10 10 10 10 SnZnOx* 20 20 20 20 TiOx: 3.5% O2
TiOx: 0% O2 0
5 5
5 10
5 15
5 Ag* 11 11 11 11 ZnO 5 5 5 5 If ₃ N ₄ * 20 20 20 20 Glass (4mm)

Layers Ref.3 Emp.3-1 TiOx 2 2 If ₃ N ₄ 30 10 SnZnOx - 20 ZnO - - TiOx: 5% O2
TiOx: 1.7% O2 10
5 10
5 Ag 12 12 ZnO 5 5 If ₃ N ₄ 20 20 Glass (4mm)

The stacks of the invention comprise a layer of SnZnO (20 nm) above and in contact with a layer or a coating based on titanium oxide.
Stacks 2-1, 2-2 and 2-3 comprise coatings based on titanium oxide (oxygen gradient coating) comprising at least two layers of titanium oxide comprising different proportions of oxygen. The first layer is deposited in contact with the silver layer and in an oxygen-free atmosphere with a thickness of 5 nanometers. This layer is therefore under-oxidized. The second layer based on titanium oxide is deposited in an atmosphere with 3.3% oxygen by volume flow and has a thickness varying from 0 to 15 nanometers. This layer is therefore more oxidized than the first.
Stack 3-1 comprises an oxygen gradient coating comprising at least two layers of titanium oxide comprising different proportions of oxygen. Both layers are deposited from a ceramic target with oxygen. The second layer is more oxidized than the first.

II. Evolution of resistance square tance and absorption
1. General case
The square resistance Rsq, corresponding to the resistance referred to the surface, is measured by induction with a Nagy SMR-12.
The square resistance and the absorption were measured before heat treatment (BT) and after heat treatments at a temperature of 650°C for 10 min (AT).
The square resistance variation was determined as follows:

∆Rsq(n)= (RsqRef.0-RsqEmp(n)) / RsqRef X 100.
The gain is positive when the resistance per sheet is improved and negative when the resistance per sheet is deteriorated following the heat treatment.
Table 5 below shows the Rsq and absorbance measurements.

Painting TT Ref.0 Ref.1 Ref.2 Emp. 1-1 Rsq (Ω/□) BT 4.50 5.01 4.26 5.61 BT ∆Rsq (%) - -11 5.3 -24 AT 3.42 3.03 3.06 3.07 AT ∆Rsq (%) - 12.3 10.5 10.2 Absorption % BT 8.5 10.7 8.8 9.2 AT 6.5 6.2 6.6 5.6

BT: Before heat treatment, AT after heat treatment.

Before heat treatment, the sheet resistance of the stacks comprising a layer based on titanium oxide TiOx_1.7% (without and with SnZnO) is degraded compared to that of the reference stack (5.01-5.61 Ω/ □ vs. 4.50Ω/□). The presence of oxygen during the deposition of the TiOx layer seems to contribute to degrading the silver layer.
After heat treatment, the sheet resistance of the stack of the invention is better than that of the reference stack Ref.0 (3.07 Ω/□ vs. 3.42 Ω/□).
On the other hand, the insertion of the SnZnO layer makes it possible to lower the absorption, before and after heat treatment (comparison Ref.1 and Emp.1-1). Before heat treatment, the absorption increases from 10.7% to 9.2% with the addition of SnZnO, but remains higher than that of the reference stack (9.2% vs. 8.5%). After heat treatment, the absorption of the stack of the invention (5.6%) is lower than that of the stack Ref.1 (6.2%) and also lower than the reference Ref.0 with Ag/ZnO (6.5%). The presence of a layer of SnZnO in contact with the layer based on titanium oxide makes it possible to reduce the absorption of the layer of TiOx_1.7% and thus of the complete stack.

2 . Influence of the presence of a coating based on titanium oxide presenting an oxygen gradient
Table 6 below presents the measurements of Rsq and absorption of the materials as a function of the thickness of the second layer of superoxidized titanium oxide.

Painting Emp.2-0 Emp.2-1 Emp.2-2 Emp.2-3 TiOx thickness_5% 0nm 5nm 10nm 15nm Rsq Ω/□ BT 4.01 3.47 3.50 3.58 AT 3.44 2.85 2.99 2.65 abs. % BT 9.3 11.7 11.2 10.3 AT 7.7 6.8 6.5 5.4

In this stack, the layer based on zinc oxide and tin is directly in contact with the layer based on under-oxidized titanium oxide.
The presence of an over-oxidized layer of titanium oxide, regardless of its thickness, makes it possible to significantly lower the square resistance before heat treatment (3.47 vs. 4.01) and after heat treatment (2.85 vs. 3.44). This square resistance is improved regardless of the thickness of the superoxidized titanium oxide layer.
After heat treatment, the Rsq remains high for the emp.2-0 comprising a layer of SnZnO in direct contact with a layer of under-oxidized TiOx with a gain between the square resistance obtained AT vs. Low BT.
When a layer of over-oxidized titanium oxide is inserted between the layer of under-oxidized titanium oxide and the layer of zinc and tin oxide, the square resistance remains low, with a gain between the square resistance obtained AT vs. BT up to 25%.
When an oxidized layer of titanium oxide is introduced between the SnZnO and TiOx(0%), the sheet resistance is therefore improved. The thicker the superoxidized titanium oxide layer, the greater this improvement. The gain of Rsq increases from 18 to 25% when the thickness of the overoxidized titanium oxide layer increases from 5 to 15 nm. The best results for square strength after heat treatment are obtained for the thickest layer of titanium oxide.
Increasing the thickness of the overoxidized titanium oxide layer from 5 nm to 15 nm, on the other hand, makes it possible to improve this absorption (10.3% vs. 11.7%) before annealing.
After heat treatment, the over-oxidized titanium oxide layer with a thickness of 15 nm combined with the layer based on zinc and tin oxide makes it possible to significantly reduce absorption: 5.4% vs. 7.7%.

Table 7 below presents the square resistance and absorption measurements in the case of material comprising an oxygen gradient coating with two layers of TiOx deposited with oxygen.

Painting Ref.0 Ref.3 Emp.3-1 Rsq Ω/□ BT 4.50 4.45 4.55 AT 3.42 2.89 3.20 abs. % BT 8.5 9.6 7.8 AT 6.5 6.2 5.4

Before heat treatment, the Rsq is neither improved nor degraded compared to the reference stack (4.50 Ω/□ vs. 4.55 Ω/□).
After heat treatment, the Rsq is lower in the case of the stack of the invention Emp.3-1 comprising the sequence Ag/TiOx_1.7%/TiOx_5%/SnZnO (3.20 Ω/□) compared to Emp.3-0 not comprising a layer of SnZnO (3.42 Ω/□).
The absorption is lower in the case of Ag/TiOx_1.7%/TiOx_5%/SnZnO stacking, before (7.8% vs. 8.5%) and after heat treatment (5.4% vs. 6.5%). The two layers of TiOx are deposited with oxygen and are therefore not very absorbent. This weak absorption of the two TiOx layers is also visible in the Ag/TiOx_1.7%/TiOx_5% stack compared to the reference Ag/ZnO: 6.2% vs. 6.5%.
By further refining the thickness of the first layer of TiOx deposited with O2 (eg, 1 nm, or even less like the thickness of a TiOx blocker), one can hope to further reduce the absorption of the stack before thermal treatment. In view of using this type of structure for an “annealed” product (non-annealed layer), it is essential to be able to reduce the absorption as much as possible.

III. Microscopic observations : hot corrosion and blurry
The morphology of the stacks is analyzed by optical microscopy (x50 magnification) after heat treatment. Table 8 lists the images taken after heat treatment.

Painting figure Ref. 1-a Ref. 1 1-b Emp.1- 1 1 C

Observations under a microscope after heat treatment show no point of hot corrosion for the stacks according to the invention with a layer of TiOx. Furthermore, the stacks of the invention do not exhibit any blurring either.
The presence of the layer of titanium oxide as an overlayer in contact with the silver makes it possible to prevent the presence of haze.

IV. Characterization of mechanical behavior
Brush resistance tests were carried out before and after heat treatment (“Erichsen brush test” before EBT heat treatment and after TT-EBT heat treatment).
Each sample is observed after a certain number of cycles: 50, 100, 200, 300 cycles.
The table below shows all the results, Rsq, Abs after heat treatment, and EBT and TT_TT_EBT tests.
The Ok boxes indicate good resistance to the EBT or TT-EBT test after 300 cycles. The figure next to it corresponds to the number of cycles to which the sample has been subjected.
The Nok boxes indicate poor resistance to the EBT or TTEBT test after 300 cycles. The number indicated next corresponds to the number of cycles from which the test becomes bad (Nok).
The results are shown in Table 9 below.

Painting Character. Rsq Ω/□
AT AT absorption % EBT
300 Cycles TT_EBT
300 Cycles Ref. ZnO 3.42 6.5 Nok: 200k NOK: 50 Ref.1 TiOx_1.7% 3.03 6.2 OK NOK: 50 Ref.2 TiOxGrad 0/5 3.06 6.6 NOK: 50 OK Emp.1-1 TiOx_1.7%-SnZnO 3.48 5.6 OK OK Ref.3 TiOxGrad 1.7/5 2.89 6.2 NOK: 50 OK Emp.3-1 TiOxGrad 1.7/5-SnZnO 3.20 5.4 OK OK

The stack comprising a layer of titanium oxide deposited in an oxidizing atmosphere 1.7% (Emp.0-1) has a good EBT, linked to the presence of O ₂ , but a poor TT-EBT.
The stack of the invention Emp.1-1 additionally comprising a layer of zinc oxide and tin makes it possible to maintain a good EBT, but above all, to also obtain a good TT-EBT. The insertion of SnZnO as an overlayer thus makes it possible to have a good TT-EBT. This example highlights the role of the combination of TiOx/SnZnO layers in the EBT mechanical test.
Good resistance of the stack of the invention Emp.3-1 TiOx gradient/SnZnO to EBT and TT_EBT is observed. By comparing the two stacks 3-0 and 3-1 differing by the presence of the SnZnO layer, it is observed that this layer indeed allows the improvement of the EBT test.

V. Characterization of scratch behavior after heat treatment
1. Visibility of scratches: EST-TT test
Images of the scratches after EST at different forces followed by heat treatment at 650°C (EST-TT) were taken. This illustrates the scratch behavior of the stack after heat treatment.
The graphs of FIGS. 2 and 3 explained by table 11 and table 10 below illustrate the visibility of the scratches (in arbitrary units) as a function of the force applied (in newtons) to carry out the EST-TT test.

Strength 0.3N 0.5N 0.8N 1N 3N 5N Ref.1 44070 41710 37330 30720 35670 37750 Emp.1-1 16750 12120 11740 11750 10030 10150 Emp.3-1 10170 9830 8580 9030 8020 5830

Painting Figure 2 Figure 3 Ref. 0 Top Curve Top Curve Emp.1-1 bottom curve - Emp.3-1 - bottom curve

A clear improvement in the case of the 1-1 and 3-1 stacks of the invention is observed compared to the reference stack Ref.0.
The scratches made between 0.3 and 5 N on the reference stack are much more visible than the scratches made at the same force on the stacks of the invention.

2. Observation of hot corrosion of scratches
FIGS. 4 and 5, explained by table 12, represent images taken under a microscope (x50 magnification) of the scratches made at 5N. This highlights the corrosion of the scratches after heat treatment for the reference stack and the absence of corrosion for the stacks of the invention Emp.1-1 and Emp.3-1.

Painting Figure 4 Figure 5 Ref.0 To To Emp.1-1 b - Emp.3-1 - b

VI. Impact on the solar factor and on the thickness of the silver layer
Based on the gains in resistance per square commonly observed in the experimental examples (gain greater than 10%), a study based on simulations in order to optimize the solar factor g was carried out.
These results were obtained by considering that:
- the materials are mounted in double glazing with the stack facing 3 in a standard configuration (4mm glass, Ar 90%, 16mm glass),
- the material coated with the stack has undergone a quenching-type heat treatment.
In order to evaluate the impact of the invention on the solar factor, on the light transmission and on the possibility of refining the silver-based functional layer, three cases were considered. These cases differ by the choice of the gain in resistance per square obtained between a reference stack and a stack of the invention corresponding to:
- no gain in resistance per square,
- a gain in resistance per square of 5%,
- a gain in resistance per square of 10%.
Objectively, with regard to the experimental results obtained above, the simulations with a gain of 10% are probably the closest to reality.
The materials according to the invention and the reference materials all have colors which satisfy the criteria defined in reference “colorboxes”.
The resistance per square Rsq is fixed, i.e. always the same with 1.97 Ohm/square for stacks with a silver layer of approximately 16 nm and 3.79 Ohm/square for stacks with a layer of silver of about 10 nm.

5.1. 16 nm silver layer stacks
The color box for stacks comprising a 16 nm silver layer is as follows:
TL (-2.5<a*T<-0.5) and (0.9<b*T<2.9)
RInt (0<a*Rint<4) and (-10.5<b*Rint<-5.5)
Rext (0<a*Rint<4) and (-10.5<b*Rext<-5.5).

Tables 13, 14, 15 and 16 list the simulated stacks.

Materials Layers Ref.4 Emp.4-0 Emp.4-5 Emp.4-10 DR If ₃ N ₄ 12 16 16 17 SnZnO 21 24 23 24 TiOx 11 10 11 10 ZnO* 5 - - - CF Ag 16 16 15.4 14.8 DR ZnO 5 5 5 5 TiOx 19 17 15 19 SiN 2 8 12 7 Glass substrate

CF: Functional layer; RD: Dielectric Coating

Materials Layers Ref.5 Emp.5-0 Emp.5-5 Emp.5-10 DR If ₃ N ₄ 28 26 19 24 SnZnO 5 10 14 4 TiOx 11 14 15 17 ZnO* 5 - - - CF Ag 16 16 15.4 14.8 DR ZnO 5 5 5 5 TiOx 18 20 20 21 SiN 6 5 6 5 Glass substrate

Materials Layers Ref.6 Emp.6-0 Emp.6-5 Emp.6-10 DR If ₃ N ₄ 26 26 26 25 SnZnO 20 20 21 20 TiOx - 5 5 5 ZnO* 5 - - - CF Ag 16 16 15.4 14.8 DR ZnO 5 5 5 5 TiOx 17 18 18 20 SiN 7 7 8 5 Glass substrate

Materials Layers Ref.7 Emp.7-0 Emp.7-5 Emp.7-10 DR If ₃ N ₄ 32 29 26 28 SnZnO 15 17 20 19 TiOx - 5 5 5 ZnO* 5 - - - CF Ag 16 16 15.4 14.8 DR ZnO 5 5 5 5 TiOx 17 16 19 17 SiN 7 10 6 12 Glass substrate

Table 17 below shows the values of solar factor and resistance per square of the materials defined above as well as the variation in solar factor (∆g) between a reference stack and a stack of the invention differing by the presence of the TiOx layer in contact with the silver instead of the ZnO layer.

Materials Rsq tl g ∆g Thickness Ag nm Ref.4 1.97 75.5 56.6 - 16 Emp.4-0 (gain 0) 1.97 76.0 57.3 +0.7 16 Emp.4-5 (gain 5) 1.97 77.4 58.8 +2.2 15.4 Emp.4-10 (gain 10) 1.97 78.1 60.1 +3.5 14.8 Ref.5 1.97 76.3 57.2 - 16 Emp.5-0 (gain 0) 1.97 77.1 58.1 +0.9 16 Emp.5-5 (gain 5) 1.97 78.1 59.2 +2.0 15.4 Emp.5-10 (gain 10) 1.97 79.7 60.7 +3.5 14.8 Ref.6 1.97 74.8 56.0 - 16 Emp.6-0 (gain 0) 1.97 75.5 57.0 +1.0 16 Emp.6-5 (gain 5) 1.97 76.7 58.4 +2.4 15.4 Emp.6-10 (gain 10) 1.97 78.1 59.8 +3.8 14.8 Ref.7 1.97 74.8 56.0 - 16 Emp.7-0 (gain 0) 1.97 75.5 57.0 +1.0 16 Emp.7-5 (gain 5) 1.97 76.8 58.4 +2.4 15.4 Emp.7-10 (gain 10) 1.97 78.0 59.8 +3.8 14.8

In all cases, it is found that the drop in Rsq induced by the solution of the invention comprising the Ag/TiOx sequence makes it possible, for a given fixed Rsq, to lower the thickness of the silver layer.
The solution of the invention makes it possible, for fixed values of resistance per square, to refine the thicknesses of the silver layer by up to 7.5%. This has the additional beneficial effect of improving the solar factor (increase in g) and in most cases increasing the light transmission.

Non-layered high index material thicker than 5nm above silver
A material according to the invention comprising a silver layer of approximately 16 nm, exhibits an increase in the solar factor of +1 to +3.8 percentage points compared to a reference material comprising a silver layer of 16 nm, mounted the same way (Emp.6-0, 6-5, 6-10 compared to Ref.6 and Emp.7-0, 7-5, 7-10 compared to Ref.7).

Material with high index layer thickness greater than 5 nm above the silver
A material according to the invention comprising a silver layer of approximately 16 nm, exhibits an increase in the solar factor of +0.7 to +3.5 percentage points compared to a reference material comprising a silver layer of 16 nm, mounted in the same way (Emp.4-0, 4-5, 4-10 compared to Ref.4 and Emp.5-0, 5-5, 5-10 compared to Ref.5) .

5.2. 10 nm silver layer stacks
The color box for stacks comprising a 10 nm silver layer is as follows:
TL (-3<a*T<-1) and (2<b*T<5)
RInt (0<a*Rint<4) and (-14.5<b*Rint<-9.5)
RExt (0<a*Rext<4) and (-13.5<b*Rext<-8.5).

Tables 18, 19, 20 and 21 list the simulated stacks.

Materials Layers Ref.8 Emp.8-0 Emp.8-5 Emp.8-10 DR If ₃ N ₄ 18 18 23 27 SnZnO 25 26 23 20 TiOx - 5 5 5 ZnO* 5 - - - CF Ag 10 10 9.65 9.25 DR ZnO 5 5 5 5 TiOx 17 19 23 22 SiN 21 18 11 15 Glass substrate

CF: Functional layer; RD: Dielectric Coating

Materials Layers Ref.9 Emp.9-0 Emp.9-5 Emp.9-10 DR If ₃ N ₄ 35 38 24 39 SnZnO 4 6 21 1 TiOx - 5 5 5 ZnO* 5 - - - CF Ag 10 10 9.65 9.25 DR ZnO 5 5 5 5 TiOx 20 21 21 16 SiN 16 16 17 24 Glass substrate

Materials Layers Ref.10 Emp.10-0 Emp.10-5 Emp.10-10 DR If ₃ N ₄ 27 36 36 25 SnZnO 9 1 6 15 TiOx 7 12 10 11 ZnO* 5 - - - CF Ag 10 10 9.65 9.25 DR ZnO 5 5 5 5 TiOx 15 17 17 18 SiN 25 24 20 20 Glass substrate

Materials Layers Ref.11 Emp.11-0 Emp.11-5 Emp.11-10 DR If ₃ N ₄ 18 19 16 19 SnZnO 21 20 26 23 TiOx 7 10 7 10 ZnO* 5 - - - CF Ag 10 10 9.65 9.25 DR ZnO 5 5 5 5 TiOx 23 20 16 23 SiN 9 20 22 10 Glass substrate

Table 22 below shows the values of solar factor and resistance per square of the materials defined above as well as the variation in solar factor (∆g) between a reference stack and a stack of the invention differing by the presence of the TiOx layer in contact with the silver instead of the ZnO layer.

Materials Rsq tl g ∆g Thickness Ag nm Ref.8 3.79 82.6 69.6 - 10 Emp.8-0 (gain 0) 3.79 82.0 70.1 +0.5 10 Emp.8-5 (gain 5) 3.79 82.2 70.7 +1.1 9.65 Emp.8-10 (gain 10) 3.79 82.2 71.5 +1.9 9.25 Ref.9 3.79 82.2 69.8 - 10 Emp.9-0 (gain 0) 3.79 82.3 70.1 +0.3 10 Emp.9-5 (gain 5) 3.79 82.3 70.8 +1.0 9.65 Emp.9-10 (gain 10) 3.79 82.2 71.2 +1.4 9.25 Ref.10 3.79 81.9 70.0 - 10 Emp.10-0 (gain 0) 3.79 81.9 70.4 +0.4 10 Emp.10-5 (gain 5) 3.79 81.9 71.0 +1.0 9.65 Emp.10-10 (gain 10) 3.79 81.4 71.6 +1.6 9.25 Ref.11 3.79 81.6 69.9 - 10 Emp.11-0 (gain 0) 3.79 82.1 70.3 +0.4 10 Emp.11-5 (gain 5) 3.79 81.9 70.7 +0.8 9.65 Emp.11-10 (gain 10) 3.79 81.7 71.5 +1.6 9.25

In all cases, it is found that the drop in Rsq induced by the solution of the invention comprising the Ag/TiOx sequence makes it possible, for a given fixed Rsq, to lower the thickness of the silver layer.
The solution of the invention makes it possible, for fixed values of resistance per square, to refine the thicknesses of the silver layer by up to 7.5%. This has the additional beneficial effect of improving the solar factor (increase in g) and in most cases increasing the light transmission.

Non-layered high index material thicker than 5nm above silver
A material according to the invention comprising a silver layer of approximately 10 nm, exhibits an increase in the solar factor of +0.3 to 1.9 percentage points compared to a reference material comprising a silver layer of 10 nm, mounted the same way (Emp.8-0, 8-5, 8-10 compared to Ref.8 and Emp.9-0, 9-5, 9-10 compared to Ref.9).

Material with high index layer thickness greater than 5 nm above the silver
A material according to the invention comprising a silver layer of approximately 10 nm, exhibits an increase in the solar factor of +0.4 to +1.6 percentage points compared to a reference material comprising a silver layer of 10 nm, mounted in the same way (Emp.10-0, 10-5, 10-10 compared to Ref.10 and Emp.11-0, 11-5, 11-10 compared to Ref.11) .

Conclusion :
The examples show that the combination of the invention allows:
- not to increase absorption after heat treatment,
- to obtain a gain in square resistance,
- for a given Rsq to lower the thickness of the silver layer and allow an increase in light transmission and solar factor,
- to obtain a good resistance to corrosion and the absence of haze,
- to obtain good resistance to the brush test after heat treatment.
In addition, the introduction of a small quantity of oxygen (<5%) during the deposition of the first layer of TiOx from a ceramic target makes it possible to obtain, after heat treatment, a gain in Rsq of 10-15 %, an absorption similar or even lower than that of an Ag/ZnO stack, as well as an improvement in the TT_EBT.

Claims (15)

Material comprising a transparent substrate coated with a stack of layers comprising at least one silver-based functional metallic layer and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that each functional metallic layer is placed between two dielectric coatings, the stack comprises:
- a coating based on titanium oxide comprising at least one layer based on titanium oxide located above and in contact with a functional metallic layer based on silver having a thickness greater than 3 nm,
- a layer based on zinc oxide and tin comprising at least 20% by mass of tin relative to the total mass of zinc and tin, located above and in contact with the layer based on titanium oxide. Material according to any one of the preceding claims, characterized in that the coating based on titanium oxide comprises at least one layer based on titanium oxide deposited from a ceramic target, in particular under stoichiometric, in an atmosphere including oxygen. Material according to the preceding claim, characterized in that the layer based on titanium oxide is deposited with a percentage of oxygen in volume flow representing between 0.1 and 10%. Material according to any one of the preceding claims, characterized in that the coating based on titanium oxide is a coating comprising an oxidation gradient, the part of the coating with an oxidation gradient in contact with the functional layer is less oxidized than the part of this coating furthest from the functional layer. Material according to the preceding claim, characterized in that the oxidation gradient coating comprises at least two layers of titanium oxide each comprising different proportions of oxygen. Material according to the preceding claim, characterized in that the coating with an oxidation gradient comprises a first layer deposited from a ceramic target, in particular substoichiometric, in an oxidizing atmosphere whose percentage of oxygen in flow represents between 0 and 4 %. Material according to Claim 6, characterized in that the first layer has a thickness of between 0.2 and 4 nm. Material according to any one of Claims 5 to 7, characterized in that the oxidation gradient coating comprises a second layer based on titanium oxide deposited from a ceramic target, in particular substoichiometric, in an atmosphere comprising higher proportions of oxygen than those used for the first layer. Material according to Claim 8, characterized in that the second layer has a thickness of between 0.2 and 30 nm. Material according to any one of the preceding claims, characterized in that the layer based on zinc oxide and tin has a thickness:
- greater than 5 nm,
- less than 40 nm. Material according to any one of the preceding claims, characterized in that the metallic functional layer is deposited above and in contact with a layer based on zinc oxide. Material according to any one of the preceding claims, characterized in that the stack comprises at least one layer comprising silicon. Material according to Claim 12, characterized in that the sum of the thicknesses of all the layers comprising silicon in the dielectric coating located between the substrate and the first silver-based functional metal layer is greater than 50% of the total thickness of the dielectric coating. 4Material according to any one of the preceding claims, characterized in that the sum of the thicknesses of all the oxide-based layers present in the dielectric coating located below the first functional metallic layer is less than 50% of the total thickness dielectric coating. Glazing comprising a material according to any one of Claims 1 to 14, characterized in that it is in the form of monolithic, laminated and/or multiple glazing.