Coated glass substrate and method of manufacturing same

Abstract

The present invention relates to a glazing comprising a glass substrate (6), on at least one main surface of which is provided a coating (7) comprising an alternating arrangement of n infrared-reflecting functional layers (2) comprising silver and n+1 dielectric coatings (1, 3), where n≧1, each functional layer being surrounded by a dielectric coating, and at least one dielectric coating comprising silver nanoparticles (4, 5) having a diameter in the range of 1 to 5 nm, in direct contact with the at least one infrared-reflecting functional layer and at a distance of up to 10 nm from the at least one infrared-reflecting functional layer. The present invention further relates to an ion implantation process for producing such glazing.

Description

[Technical Field]

[0001] The present invention relates to a coated glass substrate comprising a silver layer and having improved chemical resistance. The present invention also relates to a method for producing such a coated glass substrate.

[0002] The coated glass substrates of the present invention can be used as insulating glazing and / or solar control glazing. These glazings are also intended for installation in buildings and vehicles. The purpose is, in particular, to reduce the air conditioning effort and / or reduce excessive overheating (so-called "solar control" glazing) and / or reduce the amount of energy dissipated to the outside (so-called "low emissivity" glazing). [Background technology]

[0003] Many coatings for use on glass substrates rely on one or more silver-containing layers that reflect infrared light to improve the insulating and / or solar control properties of the glazing. Typically, such silver-containing layers are sandwiched between dielectric coatings that include one or more separate layers of oxides, nitrides, or oxynitrides that serve to protect the silver layer and improve its optical properties, particularly with regard to desired reflectance and color. The chemical resistance of such glazing is commonly improved by adding a layer, such as a layer containing silicon nitride or a mixed oxide of zinc and tin, above the silver layer.

[0004] U.S. Patent Application Publication No. 20208139935 A1 discloses a multilayer coating of alternating metal hydride nitride and silver layers, in which Ag nanoparticles of an undisclosed size diffuse from the underlying Ag layer into the overlying dielectric upon thermal or optical treatment, resulting in improved electrical conductivity. However, the Ag diffusion occurs almost entirely throughout the overlying dielectric, no improvement in chemical resistance is demonstrated, and the size of the nanoparticles is not reported.

[0005] These coatings are still found to have limited chemical durability. Summary of the Invention

[0006] One object of the present invention is to provide a coated glass substrate having good chemical resistance. The present invention particularly relates to a coating on a glass substrate comprising one or more layers deposited by magnetron sputtering.

[0007] The present invention is based on the discovery that ion implantation can significantly increase the chemical resistance of coated glass substrates, the coating comprising an alternating arrangement of n infrared-reflective functional layers containing silver and n+1 dielectric coatings (where n≧1), each functional layer being surrounded by a dielectric coating, with at least one dielectric coating being in direct contact with at least one infrared-reflective functional layer. It has been found that the at least one dielectric coating in direct contact with the at least one infrared-reflective functional layer comprises silver nanoparticles having a diameter in the range of 1 to 5 nm, at a distance of up to 10 nm from the infrared-reflective functional layer. The coating according to the present invention maintains electrical conductivity.

[0008] The present invention therefore relates to a glazing comprising a glass substrate, and on at least one main surface of the glass substrate, a coating comprising an alternating arrangement of n infrared-reflective functional layers comprising silver and n+1 dielectric coatings, where n≧1, each functional layer being surrounded by a dielectric coating, and at least one dielectric coating being in direct contact with the at least one infrared-reflective functional layer and comprising silver nanoparticles having a diameter in the range of 1 to 5 nm at a distance of up to 10 nm from the at least one infrared-reflective functional layer.

[0009] The presence of silver nanoparticles was confirmed by transmission electron microscope (TEM) images of the cross section of the coated substrate. The nanoparticles appear substantially circular, and their diameter is the equivalent cross-sectional diameter measured on the TEM image. If the nanoparticles have an irregular shape, their equivalent cross-sectional circular diameter is the diameter of a two-dimensional disk having the same area as the cross section of the nanoparticle, as determined, for example, by image analysis methods. For example, TEM images can be processed using image analysis software, such as ImageJ (developed by the National Institutes of Health, USA), to determine particle size.

[0010] To the best of our knowledge, ion implantation can play two roles in the formation of silver nanoparticles: first, by improving the diffusion of silver into the surrounding layer, and second, by imparting mobility to the components of the layer, allowing the silver to reorganize into larger nanoparticles.

[0011] For clarity, when we say that silver nanoparticles are visible at a distance of up to 10 nm from the infrared-reflecting functional layer, we mean that they are visible at a distance of up to 10 nm, but not at a distance greater than 10 nm.

[0012] The present invention further relates to a method for improving the corrosion resistance of a coated glass substrate, the method comprising the steps of: a. providing a glass substrate comprising on a major surface a coating comprising an alternating arrangement of n infrared-reflective functional layers comprising silver and n+1 dielectric coatings, where n≧1, wherein each functional layer is surrounded by a dielectric coating and at least one dielectric coating is in direct contact with at least one infrared-reflective functional layer; b. providing a source gas selected from O2 or N2, He, Ne, Ar, or Kr; ionizing the source gas so as to form ions of cO, N, He, Ne, Ar, or Kr; d. accelerating ions of O, N, He, Ne, Ar, or Kr using an accelerating voltage to form an ion beam; e. placing the glass substrate portion within the trajectory of the beam of O, N, He, Ne, Ar, or Kr ions so that the coating faces the beam, and setting the acceleration voltage to a value of at least 5 kV to 100 kV so that the at least one infrared-reflecting functional layer is implanted with ions throughout.

[0013] Advantageously, the acceleration voltage is set to a value selected between 5 kV and 100 kV. Acceleration voltages above 100 kV may also be successful, but may increase the complexity of the implantation device. More advantageously, the acceleration voltage is set to a value of at least 10 kV, and even more advantageously to a value of at least 12 kV. It has been found that acceleration voltages above 100 kV result in rapid and complete degradation of the silver-containing functional layer.

[0014] In a preferred embodiment, the O, N, He, Ne, Ar, and Kr ions are positively charged ions.

[0015] The present invention further relates to the use of implanted ions to improve the corrosion resistance of a glass substrate comprising a coating on at least one major surface of the glass substrate, the coating comprising an alternating arrangement of n infrared-reflective functional layers comprising silver and n+1 dielectric coatings, where n≧1, each functional layer being surrounded by a dielectric coating, and at least one dielectric coating being in direct contact with at least one infrared-reflective functional layer.

[0016] In the context of the present invention, the chemical resistance of a coated glass substrate should be understood to be the chemical resistance of a coating on a glass substrate as demonstrated using the climatic chamber test and the neutral salt spray test as described below.

[0017] The coating of the present invention may have a total geometric thickness T of up to 300 nm. The total thickness T is preferably 10 to 200 nm, more preferably 20 to 100 nm, in particular 40 to 70 nm.

[0018] In some embodiments, the coating of the present invention may be a solar control or insulating low-E coating.

[0019] According to one embodiment of the present invention, the coating preferably comprises an alternating sequence of n infrared-reflecting functional layers and n+1 dielectric coatings, where n=1, n=2, or n=3.

[0020] According to one embodiment of the present invention, one or more, or in particular all, layers of the multilayer stack are deposited by magnetron sputtering.

[0021] In the coating of the present invention, the infrared-reflecting functional layer is a layer consisting of silver or containing silver optionally doped with palladium or gold, for example in a proportion of up to 5% by weight, preferably about 1% by weight. The incorporation of small amounts of dopants into the silver-based layer can improve the chemical stability of the stack.

[0022] The inventors have found that in chemical resistance tests, defects are often associated with delamination occurring at the interface between the silver-based layer and a contact layer, such as a dielectric layer. DETAILED DESCRIPTION OF THE INVENTION

[0023] The infrared-reflecting functional layer advantageously has a thickness of at least 6 nm, or at least 8 nm, preferably at least 9 nm. These thicknesses are preferably up to 22 nm, or up to 20 nm, more preferably up to 18 nm. These thickness ranges can achieve the desired low emissivity and solar control functions while maintaining good light transmittance. In a coating stack having two functional layers, it may be preferable for the second functional layer, which is farthest from the substrate, to be slightly thicker than the first to achieve better selectivity. In the case of a coating stack having two functional layers, the first functional layer can have a thickness of, for example, 8 to 18 nm, and the second functional layer can have a thickness of 10 to 20 nm.

[0024] In the coating of the present invention, the dielectric coating can comprise one or more layers, each made of a dielectric material of the metal nitride, metal oxide or metal oxynitride type. From an optical point of view, the purpose of these coatings that constitute the metallic functional layer is to "antireflection" this metallic infrared-reflecting functional layer.

[0025] In the multilayer stack of the present invention, a sacrificial metal layer or suboxide barrier layer may be provided in contact with one or more infrared-reflecting functional layers above and / or below said functional layers to prevent their degradation during the deposition process and / or during strengthening or bending. Such sacrificial barrier layers are not considered part of the dielectric coating for the purposes of the present invention.

[0026] In the multilayer stack according to the invention, dielectric seed or barrier layers, in particular zinc oxide layers, preferably aluminum-doped zinc oxide layers, can be deposited by magnetron sputtering in direct contact with one or more infrared-reflecting functional layers above and / or below said functional layers in order to promote the crystal growth of the metallic functional layers (seed layers) and / or to prevent their degradation during the deposition process and / or during strengthening or bending of the (barrier layers). For the purposes of the present invention, these dielectric seed or barrier layers are considered to be part of the corresponding dielectric coating above or below the functional layer.

[0027] The multilayer stack in the present invention may be part of a larger multilayer coating in which additional layers are added after implanting ions into the multilayer stack.

[0028] When referring to implantation depth, it should be understood that the depth is measured from the outer surface of the coating towards the substrate. Furthermore, the maximum depth Dmax of the implanted ions may be greater or less than the thickness T of the coating. [Brief explanation of the drawings]

[0029] [Figure 1] 1 shows a schematic diagram of a glass substrate (6) comprising, on at least one main surface, a coating (7) comprising an alternating arrangement of n=1 infrared-reflecting functional layers (2) containing silver and n+1=2 dielectric coatings (1, 3), where the functional layers (2) are surrounded by the dielectric coatings (1, 3). Both dielectric coatings (1, 3) are in direct contact with the infrared-reflecting functional layer (2) and contain silver nanoparticles (4, 5) at a distance of up to 10 nm from the infrared-reflecting functional layer (2), the silver nanoparticles (4, 5) having a diameter in the range of 1 to 5 nm.

[0030] Generally, without limiting the scope of the present invention, the glass substrate may typically be soda-lime silicate glass, particularly clear or extra-clear glass. However, as will be appreciated by those skilled in the art, the substrate may also be another type of glass, such as borosilicate glass or alumina silicate glass. The glass substrate may be colored or may be absorbent or even nearly opaque in the visible light range.

[0031] In one embodiment, the glazing of the invention comprises implanted ions in the coating selected from ions of O, N, He, Ne, Ar or Kr, it being found that heavier ions lead to a rapid and complete degradation of the functional layer containing silver.

[0032] The implanted ions are preferably positively charged ions.

[0033] The implanted ions are preferably implanted into the coated substrate starting from the outer surface of the coating to a depth Dmax of 0.1 μm to 1 μm.

[0034] The amount or dose per surface unit of implanted ions is preferably 5×10 14 ions / cm 2 ~10 18 ions / cm 2 , advantageously 10 16 ions / cm 2 ~5×10 17 ions / cm 2 , more favorably 3 × 10 16 ions / cm 2 ~10 17 ions / cm 2 The ion dose can be controlled, for example, by the exposure time to the ion beam, and is also determined by the ion current of the ion beam. At lower doses, no improvement in durability may be observed. At higher doses, the coating may be damaged.

[0035] Surprisingly, it has been found that implanted ions can reduce the amount of defects that appear in the coating, particularly during durability testing as described below.

[0036] In one embodiment of the present invention, the trajectory of the ion beam is substantially perpendicular to the surface of the glass substrate.

[0037] In some embodiments, the glass substrate is moved relative to the ion beam to treat the entire surface in one pass or multiple passes. The glass substrate portion can be moved at a speed of 20-160 mm / s.

[0038] The inventors have found that an ion source that can obtain an ion beam containing a mixture of singly and multiply charged ions is advantageously used for ionizing the source gas. Such ion mixtures, accelerated at the same accelerating voltage, are particularly useful because they can obtain a higher fluence than monovalent ion beams. They can therefore reach a specific dose in a shorter time. Multivalent ions are also interesting because, for the same accelerating voltage, they can reach a greater implantation depth than monovalent ions. The implantation energy, expressed in electron volts (eV), is calculated by multiplying the charge of the monovalent or multivalent ions by the accelerating voltage. An ion beam containing a mixture of monovalent and multivalent ions can, for a specific accelerating voltage, produce a beam containing some doubly charged ions, e.g., N. 2+ is the corresponding singly charged ion N +This is particularly useful because it has an implantation energy twice that of the ion implantation energy ...

[0039] In one embodiment of the present invention, at least 90% of the ions in the ion beam are composed of singly and doubly charged ions of species selected from N, O, He, Ne, Ar, and Kr, with a ratio of singly charged species to doubly charged species of at least 55 / 25. + and N 2+ , O + and O 2+ , He + and He 2+ , Ne + and Ne 2+ , Ar + and Ar 2+ is.

[0040] In another embodiment, ions are implanted by sequentially implanting ions selected as singly charged ions, for example in two or more steps at different acceleration voltages.

[0041] In a preferred embodiment of the invention, a region of a glass substrate is treated at a temperature below the glass coalescence temperature of silver, which is affected, for example, by the ion current of the beam, the residence time of the treated region in the beam, and any cooling means for the substrate.

[0042] In one advantageous embodiment of the invention, implanted ions of either He, N, or O are used because they sputter less from the coating surface than heavier ions, which is particularly useful for keeping the coating and its optical energy properties intact. In another embodiment of the invention, implanted ions of N and O are used in combination.

[0043] In another advantageous embodiment of the present invention, either Ar implant ions are used since they can achieve similar performance as N ion implants at a lower dose.

[0044] In one embodiment of the present invention, several ion implantation beams are used simultaneously or sequentially to treat a glass substrate.

[0045] In one embodiment of the present invention, the total dose of ions per surface unit of area of ​​the glass substrate is achieved in a single treatment with the ion implantation beam.

[0046] In another embodiment of the invention, the total dose of ions per surface unit of area of ​​the glass substrate is obtained by several successive treatments of one or more ion implantation beams, which can use the same or different source gases to implant the same or different ions of O, N, He, Ne, Ar, or Kr.

[0047] The method of the present invention is preferably -2 mbar~10 -7 mbar pressure, more preferably 5×10 -5 mbar~6×10 -6 The procedure is carried out in a vacuum chamber at a pressure of 1000 mbar.

[0048] An example of an ion source for carrying out the method of the present invention is the Hardion+ ECR ion source from IonicsSA.

[0049] Advantageously, the ion implantation depth Dmax is 0.1 μm to 1 μm, preferably 0.1 μm to 0.5 μm. The implanted ions spread between the substrate surface and the implantation depth. The implantation depth can be adjusted by the selection of implanted ions, acceleration energy, and irradiation angle, and varies to some extent depending on the substrate.

[0050] According to the invention, the mixture of monovalent and polyvalent ions of O or N is preferably O + and O 2+ or N + , N 2+ and N 3+ or Ar + and Ar 2+ Each includes:

[0051] According to a preferred embodiment of the present invention, the mixture of monovalent and polyvalent ions of O is O + A smaller amount of O 2+ In a more preferred embodiment of the present invention, the mixture of monovalent and polyvalent ions of O is 55 to 98% O + , and 2–45% O 2+ Includes.

[0052] According to another preferred embodiment of the present invention, the mixture of monovalent and polyvalent ions of N is N + and N 2+ A smaller amount of N than each of 3+ In a more preferred embodiment of the present invention, the mixture of monovalent and polyvalent ions of N contains 40-70% N + , 20-40% N 2+ , and 2–20% N 3+ Includes.

[0053] According to another preferred embodiment of the present invention, the mixture of monovalent and polyvalent ions of Ar is Ar + A smaller amount of Ar 2+ In a more preferred embodiment of the present invention, the mixture of monovalent and polyvalent ions of Ar comprises 50-80% Ar + , 10-30% Ar 2+ , and 3 to 15% Ar 3+Includes.

[0054] The chemical durability of the coated glass substrates is tested using a climate chamber test and a salt spray test.

[0055] The neutral salt spray test according to standard EN 1096-2012 consists in exposing the coated glass to a salt spray formed by dissolving NaCl in distilled water at a temperature of 35±2°C. The test period is 10 days.

[0056] Climate chamber test (CC): This test consists in placing the specimen in a chamber filled with water saturated with an atmosphere of H2O and exposing it to temperature cycles of 2 hours each, varying the temperature from 45°C to 55°C and back to 45°C. The test period is 10 days.

[0057] Salt Spray Test (NSST): This test consists in exposing the specimens to the action of a salt mist formed by spraying them with an aqueous solution containing 50 g / l of sodium chloride, in a chamber maintained at 35°C, until the first defects appear (full details of this test are given in International Standard ISO 9227-2001).

[0058] Glass substrates A and B were implanted with ions. These glass sheets had coatings on their major surfaces deposited by magnetron sputtering. The layer order of the coatings for the different substrates is detailed in Table 1 below.

[0059] TIFF2025533343000002.tif72170

[0060] TZO is a mixed oxide of Ti and Zr, more preferably a titanium-zirconium mixed oxide with a TiO2 / ZrO2 weight ratio of 65 / 35. SiN is Si3N4. All coatings were deposited using magnetron sputtering on ordinary clear soda-lime glass. ZnO:Al is aluminum-doped zinc oxide.

[0061] The glass substrate was implanted with a mixture of monovalent and multivalent ions of He, Ar, and N, respectively. The dose was 10 15 ions / cm 2 ~8×10 16 ions / cm 2 The ion beam current was varied between 2 and 10 mA. The accelerating voltage was 40 kV. The implanted substrates remained conductive, as confirmed by measuring the sheet resistance using a non-contact measuring device, Stratometer G, from Nagy Messsysteme GmbH. The implanted glass substrates were subjected to a climate chamber test and a salt spray test to determine the number of defect sizes.

[0062] Detailed test results after ion implantation of Ar ions in A and B are shown in Table 3. These test results are rated on a scale of 0 to 5, with 5 being no degradation and 1 being very severe degradation. Without implantation, A and B would receive a test rating of 1.

[0063] Additionally, substrates A and B were implanted with He and N ions at the dose and current ranges summarized in Table 3.

[0064] In the case of all implanted samples, a significant improvement in durability was observed, especially since the initial defects observed did not significantly increase in size during the aging test. Furthermore, in the ion-implanted samples, cross-sectional TEM images show silver nanoparticles formed in the dielectric coating above and below the silver functional layer for both substrates A and B. These nanoparticles were located <10 nm from the silver functional layer. These nanoparticles had a substantially circular cross section and were estimated to be 2-4 nm in diameter.

[0065] TIFF2025533343000003.tif93170

[0066] TIFF2025533343000004.tif56170

Claims

1. A glazing comprising a glass substrate (6), the glazing comprising, on at least one main surface of the glass substrate, a coating (7) comprising an alternating arrangement of n infrared-reflecting functional layers (2) comprising silver and n+1 dielectric coatings (1, 3), where n≧1, each functional layer being surrounded by a dielectric coating, at least one dielectric coating being in direct contact with at least one infrared-reflecting functional layer and comprising silver nanoparticles (4, 5) having a diameter in the range of 1 to 5 nm at a distance of up to 10 nm from the at least one infrared-reflecting functional layer.

2. 2. Glazing according to claim 1, wherein the infrared-reflecting functional layer has a thickness of at least 6 nm and / or at most 22 nm.

3. 2. The glazing of claim 1, wherein the coating has a total geometric thickness T of at most 300 nm.

4. The glazing according to any one of claims 1 to 3, wherein the glass substrate is selected from a soda-lime silicate glass substrate, a borosilicate glass substrate, or an alumina silicate glass substrate.

5. Glazing according to any one of claims 1 to 4, comprising in the coating implanted ions selected from ions of O, N, He, Ne, Ar and Kr.

6. 6. The glazing of claim 5, wherein the implanted ions are positively charged ions.

7. 7. Glazing according to claim 5 or 6, wherein the implanted ions are implanted into the coated glass substrate starting from the outer surface of the coating to a depth Dmax of 0.1 μm to 1 μm.

8. The dose of implanted ions is 5×10 １４ ions / cm ２ ~8 x 10 １６ ions / cm ２ 7. The glazing according to claim 4, wherein

9. 1. A method for improving the corrosion resistance of a coated glass substrate, comprising: a. providing a glass substrate comprising on a major surface thereof a coating comprising an alternating arrangement of n infrared-reflective functional layers comprising silver and n+1 dielectric coatings, where n≧1, wherein each functional layer is surrounded by a dielectric coating and at least one dielectric coating is in direct contact with at least one infrared-reflective functional layer; b.O ２ or N ２ providing a source gas selected from He, Ne, Ar, or Kr; c. ionizing the source gas to form positively charged ions of O, N, He, Ne, Ar, or Kr; d. accelerating the positively charged ions of O, N, He, Ne, Ar, or Kr using an accelerating voltage to form an ion beam; e. placing the glass substrate portion within the trajectory of the beam of positively charged ions of O, N, He, Ne, Ar, or Kr so that the coating faces the beam, and setting the acceleration voltage to a value between 5 kV and 100 kV so that the ions are implanted throughout the at least one infrared-reflective functional layer; A method comprising:

10. 10. The method of claim 9, wherein in step c., the source gas is ionized to form positively charged ions.

11. 11. The method of claim 9 or 10, wherein in step c., the source gas is ionized so as to form a mixture of singly and multiply charged ions.

12. 12. The method of any one of claims 9 to 11, comprising in step e. setting the acceleration voltage to a value between 5 kV and 100 kV.

13. 1. Use of implanted ions to improve the corrosion resistance of a glass substrate, the glass substrate comprising on at least one major surface a coating comprising an alternating arrangement of n infrared-reflective functional layers comprising silver and n+1 dielectric coatings, where n≧1, each functional layer being surrounded by a dielectric coating, and at least one dielectric coating being in direct contact with at least one infrared-reflective functional layer.

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