WO2009071810A2 - Substrate provided with a multilayer stack having thermal properties - Google Patents

Abstract

The invention relates to a glass substrate (10) provided on a main face with a thin-film multilayer stack comprising a metallic functional layer (40) having reflection properties in the infrared and/or in solar radiation, especially one based on silver or a silver-containing metal alloy, and two antireflection coatings (20, 60), said coatings each comprising at least one dielectric layer (24, 64) based on silicon nitride, said functional layer (40) lying between the two antireflection coatings (20, 60), the functional layer (40) being deposited directly on an underblocker coating (30) lying between the functional layer (40) and the subjacent antireflection coating (20), and an overblocker coating (50), deposited directly on the functional layer (40), lying between the functional layer (40) and the superjacent antireflection coating (60), characterized in that in order for said substrate to be bendable and/or toughenable after the thin-film multilayer stack has been deposited, the multilayer stack includes a thin nickel-based film in the underblocker coating (30) and/or in the overblocker coating (50), said thin nickel-based film being deposited at a high vacuum pressure, equal to or greater than 2 ´ 10-3 torr, and preferably between 2.5 ´ 10-3 torr and 5 ´ 10-3 torr.

Description

 SUBSTRATE PROVIDED WITH A STACK WITH THERMAL PROPERTIES

The invention relates to a transparent substrate of mineral rigid material such as glass, said substrate being coated with a stack of thin layers comprising a metal-type functional layer that can act on solar radiation and / or long-range infrared radiation. wave.

The invention relates more particularly to the use of such substrates for manufacturing thermal insulation and / or sun protection glazings. These glazings can be intended both to equip buildings and vehicles, especially in order to reduce the air conditioning effort and / or to prevent excessive overheating (so-called "solar control" glazing) and / or to reduce the amount of energy dissipated to the outside (so-called "low emissive" glazing) caused by the ever increasing importance of glazed surfaces in buildings and vehicle interiors.

These windows can also be integrated in glazing with special features, such as heated windows or electrochromic windows. A type of layer stack known to give substrates such properties consists of a functional metallic layer with infrared reflection properties and / or solar radiation, especially a metallic functional layer based on silver or of metal alloy containing silver. The type of known stack to which the invention relates is called

"Stack on and blocker" because it has the following structure, in this order:

Substrate / underlying anti-reflective coating / sub-blocker coating / functional metallic layer / over-blocking coating / overlying anti-reflective coating + possibly a protective layer. The functional layer is thus disposed between two antireflection coatings each generally comprising a single layer which is made of a silicon nitride type dielectric material or at least one layer of this type. The purpose of these coatings which frame the functional metal layer is "to antireflect" this functional metal layer.

A blocking coating is however interposed between each antireflection coating and the functional metal layer.

The blocking coating disposed under the functional layer in the direction of the substrate promotes the crystalline growth of this layer and protects it during a possible heat treatment at high temperature, such as bending and / or quenching.

The blocking coating disposed on the functional layer opposite the substrate protects this layer from possible degradation during the deposition of the upper antireflection coating and during a possible heat treatment at high temperature, of the bending and / or quenching type.

The present invention is however limited to the field of stacks as previously described and without a wetting layer, that is to say without oxide layer between the layer of a dielectric material based on silicon nitride of the antireflection coating undercoated. and the adjacent sub-blocking coating.

The present invention is more specifically a stack of the type of the one presented above which is resistant to thermal bending and / or tempering treatment applied to glass substrates to allow them to be bombarded and / or tempered. The skilled person distinguishes two categories of stacks resistant to thermal treatment (or heat treatment) of bending and / or quenching:

1 - so-called "quenching" stacks which do not have, before the heat treatment, the desired and expected characteristics, in particular of light transmission, of color, of resistivity, ... and which acquire them during this heat treatment; coated substrates of this type stacking are therefore not usable as such by the end user (when packaging substrates to form glazing for example), but only after undergoing heat treatment;

2- so-called "bumpable" and / or "hardenable" stacks which, before the heat treatment, have acceptable characteristics and which have, after heat treatment, similar or quasi-identical characteristics, that is to say which exhibit variations in characteristics to the heat treatment which are acceptable and such that it will be difficult for an observer to distinguish by visual observation of the substrates coated with the stack which have been heat-treated substrates coated with the same stack that have not undergone heat treatment.

It is not possible for a person skilled in the art to define these two categories more precisely because, for example, a "quenching" stack may have a variation in visible light transmission at a heat treatment as low as a "quenchable" stack. but have, for example, a greater variation in light reflection in the visible or a greater variation in color.

However, the documents of the prior art and the technical documentation of the glassmakers make this distinction and the present invention is only interested in the second category of stack, the stacks "bombable" and / or "hardenable".

The invention thus applies to so-called "hardenable" substrates insofar as it is difficult to distinguish on the same building facade, for example, having glazing units incorporating substrates with a stack of thin layers in the vicinity of each other. deposition of the layers and substrates with the same stack of unhardened thin layers, by a simple global visual observation of the glazings integrating in particular the light transmission in the visible, the color in reflection and the light reflection in the visible of the glazing. - AT -

For those skilled in the art, there are stacks that do not support any heat treatment.

It is well known from European Patent Application EP ⁰ 567 735, a stack of the type described above in terms of stack structure that can not be heat treated.

In this document EP 567 735 it is explained that it is important that each blocking coating, based on nickel, has a thickness of less than 0.7 nanometer.

It is also known from European Patent Application EP ⁰ 646 551, a stack of the same type (same sequence layer, the same material for each layer) which itself may be heat treated; it is a stack "to soak" because it has strong variations, especially optical, during heat treatment bending or quenching.

It is explained in the document EP 646 551 that the solution of the preceding document (EP 567 735) can not be subjected to heat treatment presumably because the thickness of each blocking coating is not sufficient to correctly protect the functional metallic layer. based on money.

The document EP 646 551 thus indirectly recommends, for making a stack of the same type but which supports the heat treatment, that the underblocking coating is really thicker (preferably 2 to 4 times the thickness of the overblocking coating ) and it states in particular that it is preferable that this sub-blocking coating has a thickness greater than 2 nm and advises a thickness of about 4.5 nm. Moreover, the invention object of EP 646 551 is compared to a "Standard" stack whose optical and thermal characteristics are acceptable and having under the metal functional layer a 0.7 nm thick blocking layer deposited under a pressure of 2.10 ³ Torr and which it is said that it does not support any heat treatment. It is explained that this thickness is insufficient and causes holes in the functional metal layer during heat treatment. It is important to note that this thickness of the standard nickel-based sub-blocking coating of EP 646 551 is identical to that of the EP 567 735 stack, ie 0.7 nm for each of the undercoatings and -Blocking. In EP 567 735, the deposition pressure in the deposition chamber of the nickel-based sub-blocking coating is not known, but in EP 646 551 the nickel-based sub-blocking coating is deposited at very low pressure (1, 5.10 ³ Torr) and it is said in this document that the stack of EP 567 735 is reproduced under the same conditions as the stack "to soak" of the invention. Surprisingly, it has been discovered that it is possible to make this standard stack capable of undergoing heat treatment, that is to say to make the stack "to soak" even though the thickness of the coating sub-blocking remains low, especially greater than 0.7 nm, and in any case much less than 2 nm. Not only the stack can then undergo a heat treatment but in addition, the variation of these essential properties is so small that it is even possible to make it "hardenable".

The object of the invention is to overcome the drawbacks of the prior art by developing a new type of stack of layers of the type described above, which has a low resistance per square, a light transmission high and a relatively neutral color, especially in layer-side reflection, and whether these properties are kept in a restricted range whether the stack is undergoing or not, a (or) heat treatment (s) at high temperature of the type bending and / or quenching and / or annealing.

The object of the invention is thus, in its widest sense, a glass substrate provided on a main surface with a stack of thin layers according to claim 1. This thin-film stack comprises a metallic functional layer with reflection properties in infrared and / or in solar radiation, especially silver-based or of silver-containing metal alloy, and two antireflection coatings, said coatings each having at least one silicon nitride-based dielectric layer, said functional layer being disposed between the two antireflection coatings, the functional layer being deposited directly on a sub-blocking coating disposed between the functional layer and the underlying antireflection coating and the functional layer being deposited directly under an overblocking coating disposed between the functional layer and the overlying antireflection coating, characterized in that for said substrate is bumpable and / or quenchable after deposition of the thin-film stack, the stack comprises a thin nickel-based layer in the underblocking coating (30) and / or in the overblocking coating (50), said nickel-based thin layer being deposited at a high vacuum pressure equal to or greater than 2.10 ³ T orr, and preferably between 2.5 × 10 ³ Torr and 5 × 10 ³ Torr. The invention thus consists in making it possible to manufacture a stack "to be tempered", starting from a Standard stack, of the type of the Standard stack of EP 646 551, which does not support heat treatment, with a slight increase in thicknesses. layers of the blocking coatings and in particular the thickness of the sub-blocking coating. This advantage is such that it becomes possible to design a stack of the Standard stack type which is "hardenable", that is to say whose characteristics and in particular the essential optical characteristics, remain virtually unchanged during processing thermal.

Within the meaning of the present invention when it is specified that a layer or coating deposit (comprising one or more layers) is carried out directly under or directly on another deposit, it is that there can be no interposition of 'no layer between these two deposits.

The silicon nitride-based layer of the underlying antireflection coating is in contact with the substrate, directly or indirectly via a contact layer, for example based on titanium oxide (TiO ₂ ). The index of this nitride-based layer is preferably less than or equal to 2.3, while that of the contact layer is preferably greater than 2.3.

The silicon nitride layer is preferably Si ₃ N ₄ . Although the preceding formula constitutes the target stoichiometry, it is not excluded that this stoichiometry is not quite impaired in the layer finally deposited.

The or each nickel-based thin layer preferably has a thickness e such that 1.5 nm <e <5 nm, and more preferably 0.8 nm <e ≤ 1.8 nm.

In a particular variant, the thin nickel-based layer of the underblocking coating and the thin nickel-based layer of the overblocking coating have identical or nearly identical thicknesses, ie: identical to the nearest 0.2 nm (physical thickness). This (or these) thin layer (s) based on nickel is (or are), preferably deposited in the metallic form.

The thin nickel-based layer of the underblocking coating is preferably directly in contact with the functional layer and the thin nickel-based layer of the overblocking coating is preferably in direct contact with the layer. functional.

The silicon nitride-based dielectric layer of the underlying antireflection coating and / or the silicon nitride dielectric layer of the overlying antireflection coating is (or is) directly in contact with, respectively, the sub-blocking coating and / or over-blocking coating.

The silicon nitride dielectric layer of the underlying antireflection coating is thus preferably in contact with the thin nickel-based layer of the underblocking coating and / or the silicon nitride dielectric layer of the The overlying antireflection coating is preferably in contact with the thin nickel-based layer of the overblocking coating. However, it is not excluded that the underblocking coating and / or the overblocking coating contains (or contain) other layer (s), but then these other layers will preferably be more remote from the functional layer than the thin nickel-based layer of the at least one overblocking coating, or even preferably will be further from the functional layer than the thin nickel-based layer of the two blocking coatings.

The functional layer is preferably deposited at a high vacuum pressure equal to or greater than 2.10 ³ Torr but less than 10 ² Torr, and preferably between 2.5.10 ³ Torr and 5.10 ³ Torr. Indeed, the thin layer (or layers) based on nickel and the functional layer are preferably deposited in the same atmosphere, under the same pressure.

In a particular variant, the high vacuum pressure is between 3.10 ³ Torr and 4.5 × 10 ³ Torr, and is preferably of the order of 3.5 × 10 ³ Torr.

Preferably, the or each nickel-based thin layer comprises at least 50 atomic percent Ni.

In a particular version, at least one nickel-based thin layer, and in particular that of the overblocking coating, comprises chromium, preferably in atomic quantities of 80% of Ni and 20% of Cr.

In this particular version, at least one nickel-based thin layer, and in particular that of the overblocking coating, consists of a NiCr alloy present in metallic form if the substrate provided with the thin-film stack has not undergone heat treatment of bending and / or quenching after deposition of the stack, said alloy being at least partially oxidized if the substrate provided with the stack of thin layers has undergone at least one bending heat treatment and / or quenching after depositing the stack. In another particular version, at least one nickel-based thin layer, and in particular that of the over-blocking coating, comprises titanium, preferably in atomic amounts of 80% Ni and 20% Ti.

In this other particular version, at least one nickel-based thin layer, and in particular that of the over-blocking coating, consists of a NiTi alloy present in metallic form if the substrate provided with the thin-film stack has not undergone heat treatment of bending and / or quenching after deposition of the stack, said alloy being at least partially oxidized if the substrate provided with the stack of thin layers has undergone at least one bending heat treatment and / or quenching after depositing the stack.

The substrate also comprises, preferably, a last layer ("overcoat" in English), that is to say a protective layer farthest from the substrate, based on oxide, deposited preferably under stoichiometric, and in particular based on TiO _x (where x is a number less than 2). This layer is found oxidized essentially stoichiometrically in the stack after deposition.

This protective layer preferably has a thickness of between 1 and 10 nm.

The antireflection coatings arranged one below the metal functional layer and the other above each have a physical thickness of between 10 and 50 nm and the metal functional layer has a physical thickness of between 5 and 20 nm.

The glazing according to the invention incorporates at least the carrier substrate of the stack according to the invention, optionally associated with at least one other substrate. Each substrate can be clear or colored. At least one of the substrates may be colored glass in the mass. The choice of the type of coloration will depend on the level of light transmission and / or the colorimetric appearance sought for the glazing once its manufacture is complete. Thus for glazing intended to equip vehicles, certain standards require that the windshield have a light transmission T _L of about 75% and other standards impose a light transmission T _L of about 65%; such a level of transmission is not required for side windows or roof-car, for example. Examples of tinted glasses which can be retained are those which, for a thickness of 4 mm, have a T _L of 65% to 95%, an energy transmission T _E of 40% to 80%, a wavelength transmission dominant from 470 nm to 525 nm associated with a transmission purity of 0.4% to 6% according to Illuminant D ₆₅ , which can be "translated" into the colorimetry system (L, a *, b *) by transmission values of a * and b * respectively between -9 and 0 and between -8 and +2. For glazing intended to equip buildings, the glazing preferably has a light transmission T _L of at least 75% or more for "low-emissive glazing" applications, and a light transmission T _L of at least 40 % or more for "solar control glazing" applications.

The glazing according to the invention may have a laminated structure, in particular associating at least two rigid substrates of the glass type with at least one thermoplastic polymer sheet, in order to present a glass-like structure / thin-film stack / sheet (s) / glass. The polymer may especially be based on polyvinyl butyral PVB, ethylene vinyl acetate EVA, PET polyethylene terephthalate, PVC polyvinyl chloride.

The glazing may also have a so-called asymmetrical laminated glazing structure, combining a rigid glass-type substrate with at least one polyurethane-type polymer sheet with energy absorber properties, optionally combined with another polymer layer with properties " self-healing ". For more details on this type of glazing, it is possible to refer in particular to patents EP-0 132 198, EP-0 131 523, EP-0 389 354.

The glazing may then have a glass-like structure / stack of thin layers / sheet (s) of polymer.

The glazings according to the invention are capable of undergoing heat treatment without damage for the stack of thin layers. They are therefore optionally curved and / or tempered. The glazing may be curved and / or tempered by being constituted by a single substrate, the one provided with the stack. It is then a glazing said

"Monolithic". In the case where they are curved, in particular to form glazing for vehicles, the stack of thin layers is preferably on an at least partially non-flat face.

The glazing may also be a multiple glazing, in particular a double glazing or triple glazing, at least the carrier substrate of the stack being curved and / or tempered. It is preferable in a multiple glazing configuration that the stack is disposed so as to be turned towards the interleaved gas blade side. In a laminated structure, the carrier substrate of the stack may be in contact with the polymer sheet.

When the glazing is monolithic or multiple of the double glazing type or triple glazing or laminated glazing, at least the carrier substrate of the stack may be curved or tempered glass, this substrate may be curved or tempered before or after the deposit of stacking.

The invention also relates to the method of manufacturing the substrates according to the invention, which consists in depositing the stack of thin layers on its substrate by a vacuum technique of the cathode sputtering type possibly assisted by magnetic field. However, it is not excluded that the first layer (s) of the stack may be deposited by another technique, for example by a pyrolysis type thermal decomposition technique.

The invention furthermore relates to a method of manufacturing a glass substrate provided on a main surface with a stack of thin layers, in particular of the substrate according to the invention, the stack comprising a metallic functional layer with reflection properties in the and / or in solar radiation, in particular based on silver or metal alloy containing silver, and two antireflection coatings, said coatings each comprising at least one dielectric layer based on silicon nitride, said layer functional being disposed between the two anti-reflective coatings, the functional layer being deposited directly on a sub-blocking coating disposed between the functional layer and the underlying antireflection coating and the functional layer being deposited directly under an over-blocking coating disposed between the functional layer and the coating antireflection overlying.

This method is remarkable in that the stack of thin layers is deposited on the substrate by a vacuum technique of the cathode sputtering type possibly assisted by magnetic field and in that for said substrate is bumpable and / or quenchable after the deposit of the stack of thin layers, a thin nickel-based layer is deposited in the underblocking coating and / or in the overblocking coating at a high vacuum pressure equal to or greater than 2.10 ³ Torr, and preferably included between 2.5.10 ³ Torr and 5.10 ³ Torr.

In addition, the functional layer is also preferably deposited at a high vacuum pressure equal to or greater than 2.10 ³ Torr but less than 10 ² Torr, and preferably between 2.5.10 ³ Torr and 5.10 ³ Torr. Indeed, the thin layer (or layers) based on nickel and the functional layer are preferably deposited in the same atmosphere, under the same pressure. This high vacuum pressure is preferably between 3.10 ³

Torr and 4.5 × 10 ³ Torr, and is more preferably of the order of 3.5 × 10 ³ Torr.

The or each nickel-based thin layer preferably has a thickness e such that 1.5 nm <e <5 nm, and more preferably 0.8 nm <e ≤ 1.8 nm.

The invention furthermore relates to the use of the substrate according to the invention, for producing a substrate which is bendable and / or quenchable after the deposition of the stack of thin layers and which preferably has, to the heat treatment, a variation of light transmission in the visible range ΔT _L <5, and preferably ΔT _L <4.5, or even ΔT _L <4 and / or a variation colorimetric reflection in stacking side and / or substrate side: ΔE <6, and preferably ΔE <5, or ΔE <4.5.

The details and advantageous characteristics of the invention emerge from the following nonlimiting examples, illustrated with the aid of the attached figures:

FIG. 1 illustrates a functional monolayer stack according to the invention, the functional layer being provided with a sub-blocking coating and an over-blocking coating and the stack being further provided with an optional protective coating ; FIG. 2 illustrates a table summarizing the essential optical and thermal characteristics of the examples produced and the variations of these characteristics after heat treatment, as well as the mechanical and chemical characteristics of these examples; and

FIG. 3 illustrates a table summarizing the essential optical and thermal characteristics of the examples made after mounting in a double glazing unit and the variations of these characteristics after heat treatment and then mounting in a double glazing unit of identical structure.

In the figure illustrating stacks of layers, the proportions between the thicknesses of the different materials are not rigorously respected in order to facilitate their reading.

Moreover, in all the examples below, the stack of thin layers is deposited on a substrate 10 of soda-lime glass with a thickness of 4 mm.

In addition, for these examples, in all cases where a heat treatment was applied to the substrate, it was an annealing for about 5 minutes at a temperature of about 660 ^° C. followed by a cooling at ambient air (about 20 ⁰ C), in order to simulate a heat treatment bending or quenching. Thus, for each of the examples, when a characteristic was measured before this heat treatment it is classified in the column: BHT and when it was measured after this heat treatment it is classified in the column: AHT. The variation of this characteristic in the heat treatment is indicated by the letter "Δ".

A series of tests was carried out.

Three examples, numbered 1 to 3, were first made on the basis of the functional monolayer stacking structure illustrated in FIG. 1 in which the functional layer 40 is provided with a sub-blocking coating 30 and a coating. overblocking 50 respectively immediately under and immediately on the functional layer 40.

In this stack also, a lower antireflection coating 20 is deposited immediately under the underblocking coating 30 and in contact with the substrate 10 and an upper antireflection coating 60 is deposited immediately on the overblocking coating 50.

In FIG. 1, it can be seen that the lower antireflection coating 20 has a single antireflection layer 24 and that the upper antireflection coating 60 has a single antireflection layer 64, but that the antireflection coating 60 may be surmounted by an optional protective coating 70 comprising a thin layer, in particular of oxide.

Table 1 below illustrates the physical thicknesses (and not the optical thicknesses) in nanometers of each of the layers of Examples 1 to 3:

Table 1 The depot installation used to perform these tests comprises four sputtering chambers provided with cathodes and equipped with targets of suitable materials under which the substrate 11 passes successively.

These deposit conditions for each of the chambers are as follows: Chamber 1: the layer 24 based on Si ₃ N ₄ is deposited by reactive sputtering using an aluminum doped silicon metal target (8% by weight of the target), under a pressure of 2.5 mTorr in an atmosphere composed of 40% argon and 60% nitrogen,

- Chamber 2: the NiCr layer of the underlying blocking coating 30 and the NiCr layer of the underlying blocking coating 50 are each deposited with a NiCr alloy metal target and the layer 40 with silver base is deposited using a silver target, the depositing pressure inside this chamber No. 2 being 3.5 mTorr and the atmosphere being pure argon, - Chamber 3 : as in chamber 1, the layer 64 based on Si ₃ N ₄ is deposited by reactive sputtering using an aluminum-doped silicon metal target (8% by weight of the target), under a pressure 2.5 mTorr in an atmosphere composed of 40% argon and 60% nitrogen,

- Chamber 4: the protective layer 70 of TiO _x is deposited using a ceramic target in an atmosphere of 90% argon and 10% oxygen.

The final stoichiometry of the layer is not exactly known because this layer undergoes additional oxidation once the coated substrate is out of the deposition machine and is exposed to the open air and a fortiori during the eventual heat treatment . The power densities and running speeds of the substrate 10 are adjusted in a known manner to obtain the desired layer thicknesses.

It should be noted that each NiCr layer is deposited in metallic form from a metal target containing 80 atomic% of Ni and 20 atomic% of Cr, in a neutral atmosphere, and that each layer is is in a partially oxidized state in the stack after it has undergone the possible heat treatment.

The silicon nitride layer 24 of the underlying antireflection coating 20 is in contact with the underblocking coating 30 and the silicon nitride layer 64 of the overlying antireflection coating 60 is in contact with the overcoat coating. -blocking 50.

The optical, mechanical and chemical characteristics of the substrates of these examples are reported in Table 2 of FIG. 2 and the optical characteristics of these substrates mounted in double glazing are reported in Table 3 of FIG.

The structure of the double glazing unit ("DGLJ") is called "6-15-6", that is to say that the glazing consists of a substrate according to the invention of thickness 6 mm associated with another non-coated light substrate of a thickness of 6 mm, these substrates being separated by a spacer space of a thickness of 15 mm made of 90% argon, the face of the substrate according to the invention being turned towards the interspace.

In this table, the optical characteristics presented consist of:

- T _Lvis , visible light transmission T _L in%, measured according to illuminant D65,

- _{ΔT Lvis} , variation in the heat treatment of light transmission T _L in the visible,

- colors in transmission L _τ *, a _τ * and b _τ * in the LAB system measured according to the illuminant D65, - ΔE _T , variation in the heat treatment of color in reflection at the layer side = (Δa _τ ^{* 2} + Δb _τ ^{* 2} + ΔL _T ^{* 2} ) ' ^{/ 2} ,

- R _LVISC , light reflection R _L in visible in%, measured on the layer side, according to illuminant D65,

- reflection colors L _RC *, a _RC * and b _RC * in the LAB system measured according to illuminant D65, layer side, - ΔE _RC , variation in the heat treatment of color in reflection at the layer side = (Δa _RC ^{* 2} + Δb _RC ^{* 2} + ΔL _RC ^{* 2} ) ^1/2 ,

- R _Lviss , light reflection R _L in the visible in%, measured on the substrate side (opposite side to the stack of layers, according to the illuminant D65,

- reflection colors L _RS *, a _RS * and b _RS * in the LAB system measured according to illuminant D65, layer side,

- ΔE _RS , variation in color reflection in substrate reflection = (Δa _RS ^{* 2} + Δb _RS ^{* 2} + ΔL _RS ^{* 2} ) ' ^{/ 2} , - FS, solar factor, calculated according to EN 410.

The tests have undergone a number of mechanical and chemical tests, the realization of which is detailed below:

- EBT = Erichsen Brush Test: it involves rubbing the stack with a brush of polymer material, the stack being covered with water; the sample has passed the test if no mark is visible to the naked eye and is marked "OK".

- EST = Erichsen test at the tip: it is a question of postponing the value of the force necessary, in Newton, to realize a scratch in the stack during the realization of the test (tip of Van Laar, ball of steel) ; here, two tests were carried out, either at 1 N or at 10 N;

- Taber 500g 100t: it is a question of postponing the amount of stack remaining in% of remaining surface after a Taber test carried out after having applied a roll of abrasive 500 g during 100 turns; - HCL = hydrochloric acid test: it is a question of plunging a sample of 5x10 cm for 8 minutes in a solution of HCl (concentration = 0,01M / L) brought to 36 ° C (without agitation). The sample is then rinsed with deionized water, dried, then observed with the eye and the light microscope and its optical properties in reflection in the visible layer side are measured using a spectrophotometer and compared to those measured. before testing. If the observations to the eye and the microscope do not reveal defects and that the optical variation ΔE (R _Lvi sc) during the test is less than 2, so the sample is considered to be resistant to this test and is marked "OK"". - HH = High humidity test: this is to place a sample of

10x1 Ocm for 5 days in a climatic chamber with controlled atmosphere (100% humidity and 40 ⁰ C). The observations (eye, microscope) and the measurement of the optical properties after the test give the same information as for the HCl test on the resistance or not of the sample to the HH test and the notation operates in the same way.

The stacks of Examples 1 to 3 are stackable stacks in the sense of the present document since for each example the light transmission variation in the visible ΔT _Lvis of the substrates is less than and equal to or less than 2, the color variation in reflection on the side ΔE _RC layers of the substrates is less than or equal to 6 and the reflection of color in reflection on the substrate side ΔE _RS is less than or equal to 3.

It is therefore difficult to distinguish substrates according to one of Examples 1 to 3 having undergone heat treatment of the substrates respectively of this same example which have not undergone heat treatment, when they are arranged side by side.

The analysis in Table 2 of Figure 2 shows that the visible light transmission of Examples 1 to 3 is certainly not very high, but it is however sufficient for the intended applications.

It has been found that the mechanical strength, both Taber test and EBT and EST tests of Examples 1 to 3 is very good.

The resistance to HCl and HH chemical tests of these examples is also very good. The mechanical strength of the stack according to the invention can be further improved if a protective layer 70 is provided.

An additional example numbered 1 'has been made. The stack of this example is identical to that of Example 1 except that the thin nickel-based layer of the overblocking coating 50 is not NiCr but NiTi.

As for example 1, it is deposited in metallic form from a metal target containing 80 atomic% of Ni, in a neutral atmosphere, but unlike in example 1, the target contains 20 atomic% of Ti .

As in Example 1, the layer is in a partially oxidized state in the stack after it has undergone a heat treatment.

Before heat treatment, the light transmission in the visible of the additional example is slightly lower than that of example 1, but the color variation in transmission expressed by ΔE _T of the additional example is lower than in the case of Example 1.

It is therefore even more difficult to distinguish substrates of the further heat-treated example from substrates of the additional example that have not been heat-treated when they are side-by-side.

Moreover, the general mechanical strength of this stack of the additional example is generally as good as that of the example

1 or even slightly better with respect to the EST test. This is all the more surprising since it is known that for monolayer blocking coatings (the layer being one or more constituents) the Ti metal layers generate, for the most part, problems of mechanical strength of the stack. , especially after heat treatment; scratches can occur especially during transport between the place where the deposition of the stack is performed on the substrate and the place is operated the integration of this substrate in a glazing, in particular a multiple glazing (double glazing, triple glazing, laminated glazing, ...).

Furthermore, the overall chemical resistance of this stack of the additional example is generally as good as that of Example 1.

The present invention is described in the foregoing by way of example. It is understood that the skilled person is able to achieve different variants of the invention without departing from the scope of the patent as defined by the claims.

Claims

1. Glass substrate (10) provided on a main face with a stack of thin layers comprising a functional layer (40) having metallic properties of reflection in the infrared and / or in the solar radiation, in particular based on silver or of silver-containing metal alloy, and two antireflection coatings (20, 60), said coatings each having at least one silicon nitride dielectric layer (24, 64), said functional layer (40) being disposed between the two antireflection coatings (20, 60), the functional layer (40) being deposited directly on a sub-blocking coating (30) disposed between the functional layer (40) and the underlying antireflection coating (20) and the layer functional member (40) being directly deposited under an overblocking coating (50) disposed between the functional layer (40) and the overlying antireflection coating (60), characterized in that for said substrate to be bendable and / or quenchable after deposition of the thin-film stack, the stack comprises a thin nickel-based layer in the underblocking coating (30) and / or in the overblocking coating (50), said thin layer nickel-based composition being deposited at a high vacuum pressure equal to or greater than 2.10 ³ Torr, and preferably between 2.5.10 ³ Torr and 5.10 ³ Torr. 2. Substrate (10) according to the preceding claim, characterized in that the or each nickel-based thin layer having a thickness e such that 1.5 nm <e <5 nm. Substrate (10) according to claim 1 or 2, characterized in that the underblocking coating (30) and the overblocking coating (50) each comprise a thin layer of nickel having identical thicknesses or almost identical. 4. Substrate (10) according to any one of claims 1 to 3, characterized in that the dielectric layer (24) based on silicon nitride underlying antireflection coating (20) and / or the layer silicon nitride dielectric (64) of the overlying antireflection coating (60) is in direct contact with, respectively, the sub-blocking coating (30) and / or overlocking coating (50). 5. Substrate (10) according to any one of claims 1 to 4, characterized in that the thin nickel-based layer of the sub-blocking coating (30) and / or the thin nickel layer of the coating of overblocking (50) is (or is) directly in contact with the functional layer (40). 6. Substrate (10) according to any one of claims 1 to 5, characterized in that the functional layer (40) has been deposited at a high vacuum pressure equal to or greater than 2.10 ³ Torr, and preferably between 2.5 × 10 ³ Torr and 5.10 ³ Torr. 7. Substrate (10) according to claim 1 or 6, characterized in that said high vacuum pressure is between 3.10 ³ Torr and 4.5.10 ³ Torr and is preferably of the order of 3.5.10 ³ Torr. 8. Substrate (10) according to any one of claims 1 to 7, characterized in that at least one thin nickel-based layer, and in particular that of the over-blocking coating (50), comprises chromium, preferably in atomic amounts of 80% Ni and 20% Cr. 9. Substrate (10) according to claim 8, characterized in that at least one thin nickel-based layer, and in particular that of the over-blocking coating, consists of a NiCr alloy present in metallic form if the substrate provided with the stack of thin layers has not undergone bending heat treatment and / or quenching after the deposition of the stack, said alloy being at least partially oxidized if the substrate provided with the stack of thin layers has has undergone at least one bending heat treatment and / or quenching after the deposition of the stack. 10. Substrate (10) according to any one of claims 1 to 7, characterized in that at least one thin layer based on nickel, and particularly that of the overblocking coating (50), comprises titanium, preferably in atomic amounts of 80% Ni and 20% Ti. 11. Substrate (10) according to claim 10, characterized in that at least one thin nickel-based layer, and in particular that of the over-blocking coating, consists of a NiTi alloy present in metallic form if the substrate provided with the stack of thin layers has not undergone bending heat treatment and / or quenching after the deposition of the stack, said alloy being at least partially oxidized if the substrate provided with the stack of thin layers has has undergone at least one bending heat treatment and / or quenching after the deposition of the stack. 12. Substrate (10) according to any one of claims 1 to 11, characterized in that it comprises a final layer, a protective layer (70) farthest from the substrate, based on oxide, deposited preferably under stoichiometric, and especially based on TiO _x . 13. Glazing incorporating at least one substrate (10) according to any one of claims 1 to 12, optionally associated with at least one other substrate mounted monolithic glazing or multiple glazing type double glazing, triple glazing or laminated glazing. 14. A method of manufacturing a glass substrate (10) provided on a main face with a stack of thin layers, in particular the substrate according to any one of claims 1 to 12, the stack comprising a functional layer (40). metal with infrared reflection properties and / or solar radiation, in particular silver-based or silver-containing metal alloy, and two antireflection coatings (20, 60), said coatings each comprising at least a dielectric layer (24, 64) based on silicon nitride, said functional layer (40) being disposed between the two antireflection coatings (20, 60), the functional layer (40) being deposited directly on a sub-blocking coating (30) disposed between the functional layer (40) and the underlying anti-reflection coating (20) and the functional layer (40) being deposited directly under an over-blocking coating (50) disposed between the functional layer (40) and the overlying antireflection coating (60), characterized in that the stack of thin layers is deposited on the substrate by a technique under vacuum of the cathodic sputtering type possibly assisted by a magnetic field and in that for said substrate to be bumpable and / or quenchable after the deposition of the stack of thin layers, a thin nickel-based layer is deposited in the sub-coating; blocking (30) and / or in the overlocking coating (50) at a high vacuum pressure equal to or greater than 2.10 ³ Torr, and preferably between 2.5.10 ³ Torr and 5.10 ³ Torr. 15. The method of claim 14, characterized in that the functional layer (40) is deposited at a high vacuum pressure equal to or greater than 2.10 ³ Torr, and preferably between 2.5.10 ³ Torr and 5.10 ³ Torr. The method of claim 15, characterized in that the functional layer (40) is deposited at the same high vacuum pressure as the underblocking coating (30) and the overblocking coating (50). 17. Method according to any one of claims 14 to 16, characterized in that said high vacuum pressure is between 3.10 ³ Torr and 4.5.10 ³ Torr and is preferably of the order of 3.5.10 ³ Torr. 18. A method according to any one of claims 14 to 17, characterized in that the or each nickel-based thin layer has a thickness e such that 1.5 nm <e <5 nm. 19. Use of the substrate according to any one of claims 1 to 12, for producing a substrate which is bumpable and / or quenchable after the deposition of the stack of thin layers and which preferably has, to the heat treatment a variation of visible light transmission ΔT _L <5 and / or a colorimetric variation in reflection ΔE <6.