阅读说明：本技术 盖板、其制造方法及用途 (Cover plate, method for the production thereof and use thereof ) 是由 Y·格努吕 A·哈恩 C·亨恩 A·兰格 于 2021-04-28 设计创作，主要内容包括：本发明总体上涉及一种盖板、其制造方法及用途。(The present invention generally relates to a cover plate, a method for manufacturing the same and use thereof.)

1. A cover plate (1) comprising:

a glass or glass-ceramic substrate (10) having a first main surface (11) and a second main surface (12), and

a coating (2) arranged on at least one main surface (11, 12) of the glass or glass-ceramic substrate (10) in at least one region (100) of the cover plate (1),

wherein the coating (2) comprises at least one compound of formula A_xB_yO₄Or predominantly or substantially or completely from at least one mixed oxide of the formula A_xB_yO₄The mixed oxide of (a) and (b),

wherein the molar ratio of A to B is between at least 0.3 and at most 0.7,

wherein the mixed oxide and/or the coating (2) is at least partially crystalline, in particular polycrystalline, and

wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and

wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof, and wherein the coating (2) preferably has a light transmission of more than 70%.

2. The cover sheet (1) according to claim 1, wherein the coating (2) has a thickness between above 0.05 μ ι η and below 3 μ ι η.

3. Cover plate (1) according to claim 1 or 2,

wherein the coating (2) is transparent and uncolored,

wherein, preferably, the color location E of the cover plate (1) is determined in a partial region (101) in which only the coating (2) is arranged on the main surfaces (11, 12) of the glass or glass-ceramic substrate (10)₁₀₁And a color location E of the cover plate (1) in a region (110) in which no coating is arranged on the glass or glass-ceramic substrate (10)₁₁₀When the difference Δ E between them is at most less than 20, preferably less than 15, particularly preferably less than 10, the coating (2) is said to be transparent and uncolored,

in this case, it is particularly preferred that the color location E in the partial region (110) is determined in the la b color system₁₁₀And a color position E in the region (101)₁₀₁And the difference value Δ E of the color positions is calculated according to the following formula:

wherein the color position E₁₁₀By colour coordinates a₁₁₀、b*₁₁₀、L*₁₁₀Given, and the color location E₁₀₁By colour coordinates a₁₀₁、b*₁₀₁、L*₁₀₁Given, and preferably determined in measurements with respect to white tiles, respectively, in particular using a CM-700d spectrophotometer by Konica-Minolta.

4. The cover plate (1) according to any one of claims 1 to 3, wherein the cover plate has a thickness of between 2mm and 8mm, preferably between 4mm and 6 mm.

5. The cover sheet (1) according to any one of claims 1 to 4, wherein the haze of the cover sheet (1) measured according to ASTM-D1003 is less than 5%, preferably less than 2%, and particularly preferably less than 1%, in a partial region (101) of the region (100) of the cover sheet (1) in which only the coating (2) is arranged on only one main surface (11, 12) of the glass or glass-ceramic substrate (10).

6. The cover plate (1) according to any one of claims 1 to 5, wherein the hardness of the coating (2) determined in the measurement method according to or in accordance with DIN EN ISO14577-1 and DIN EN ISO14577-4 is 6GPa to 11 GPa.

7. The cover sheet (1) according to any one of claims 1 to 6, wherein the coating (2) covers substantially the entire surface of the main surface (11, 12) of the glass or glass-ceramic substrate (10).

8. The cover sheet (1) according to any one of claims 1 to 7, comprising a further coating (3),

wherein the further coating (3) is arranged on the same main surface (11, 12) of the glass or glass-ceramic substrate (10) as the coating (2) and covers at least or only partially the main surface (11, 12),

wherein the further coating (3) is arranged between the glass or glass-ceramic substrate (10) and the coating (2).

9. The cover plate (1) according to any one of claims 1 to 8, wherein the glass or glass ceramic substrate (10)

Is transparent and uncolored, or

-is transparent and coloured.

10. The cover sheet (1) according to any one of claims 1 to 9, wherein the coating (2) is arranged on the main surface (11, 12) which in operational use of the cover sheet (1) faces the user and is thereby designed as a top or front surface.

11. Method for manufacturing a cover plate (1), preferably a cover plate (1) according to any one of claims 1 to 10, comprising the steps of:

-providing a glass or glass-ceramic substrate (10),

-introducing the glass or glass-ceramic substrate (10) into a coating chamber,

-providing a ceramic or metal target comprising components A and B, wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof,

providing a gas as reactive gas, wherein the gas is preferably oxygen,

-setting a pressure in the coating chamber, wherein the pressure is at least 1 x 10^-3mbar and at most 5 x 10^-2The mbar of the water is between the mbar,

-setting a temperature in the coating chamber of more than 40 ℃, wherein the manufacturing temperature is preferably at most 350 ℃,

coating by vapor deposition or sputtering, wherein the sputtering can be carried out as direct-current sputtering or pulsed sputtering, for example as medium-frequency or high-frequency sputtering,

whereby at least one main surface (11, 12) is at least partially coated with a coating (2), said coating (2) comprising a formula A_xB_yO₄Or predominantly or substantially or completely of the formula A_xB_yO₄The mixed oxide of (a) and (b),

wherein the molar ratio of A to B is between at least 0.3 and at most 0.7,

wherein the mixed oxide and/or the coating (2) is at least partially crystalline, in particular polycrystalline,

wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and

wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof, and

wherein the coating (2) preferably has a light transmission of more than 70%.

12. Method for manufacturing a cover plate (1), preferably a cover plate (1) according to any one of claims 1 to 10, comprising the steps of:

-providing a glass or glass-ceramic substrate (10),

-introducing the glass or glass-ceramic substrate (10) into a coating chamber,

-providing a ceramic or metal target comprising components A and B, wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof,

providing a gas as reactive gas, wherein the gas is preferably oxygen,

-setting a pressure in the coating chamber, wherein the pressure is at least 1 x 10^-3mbar and at most 5 x 10^-2The mbar of the water is between the mbar,

-setting a temperature in the coating chamber of more than 40 ℃, wherein the manufacturing temperature is preferably at most 350 ℃,

coating by vapor deposition or sputtering, wherein the sputtering can be carried out as direct-current sputtering or pulsed sputtering, for example as medium-frequency or high-frequency sputtering,

whereby at least one main surface (11, 12) is at least partially coated with a coating (2) comprising a compound of formula A_xB_yO₄Or predominantly or substantially or completely of the formula A_xB_yO₄The mixed oxide of (a) and (b),

wherein the molar ratio of A to B is between at least 0.3 and at most 0.7,

wherein the mixed oxide and/or the coating (2) is at least partially crystalline, in particular polycrystalline,

wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and

wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof, and

wherein the coating (2) preferably has a light transmission of more than 70%,

further comprising at least one of the following features:

-post-treatment of the coating (2) by a further treatment step in the form of a heat treatment in an oven, preferably a ceramization oven or a tempering oven, by laser input, by flash lamp treatment, by UV post-treatment, by additionally inputting plasma, for example by means of an oxygen plasma in vacuum and/or by means of plasma lines in the atmosphere and/or by applying a flame,

adding further components comprising or consisting of titanium or silicon or a mixture of two elements, wherein the proportion of further components is less than 10%, preferably less than 5%, particularly preferably less than 2%, based on the molar proportion or mole, to obtain a mixture comprising compound A_xB_yC_zO₄Wherein z is significantly less than x and y.

13. A cover sheet prepared or capable of being prepared according to the method of claim 11 or 12, in particular according to any one of claims 1 to 10.

14. Use of the cover sheet (1) according to any one of claims 1 to 10 and 13 and/or of the cover sheet (1) prepared in the process according to claim 11 or 12 as cooking surface, display, oven viewing window, scanner cover, optical element/filter, viewing window, countertop, window pane, glass pane in the field of consumer electronics, glass packaging, watch glass, protective screen.

Technical Field

The present invention generally relates to a cover plate, a method for manufacturing the same and use thereof.

Background

The cover is used, for example, in furniture and separates a region in which, for example, electronic components are arranged from a user region. For example, the cover plate may also be used as a so-called cooking plate in a cooker. Another field of application for the cover plate is, for example, the use of the cover plate as a viewing window for a fireplace in an oven, fireplace or other heating device.

As a result, the cover plate may be subjected to considerable thermal stresses, typically during operational use.

However, it has been shown again that the mechanical stresses to which the cover plate is subjected in use can also be considerable. This includes, for example, wear or scratch loads, which can lead to considerable wear of the surface of such a cover plate and/or of the surface of a coating (for example a so-called decorative layer, which is used, for example, for identifying a so-called functional area of the heating panel) or of the surface of other coatings arranged on the surface of the cover plate.

It should also be noted here that not only the heat resistance of the material and its wear resistance (e.g. the hardness of the layer) but also the chemical resistance is important. Because, for example, when the cover plate is used as a cooking surface or as a viewing window for thermal applications (e.g. in ovens or fireplace), corrosive substances may come into contact with the cover plate, especially at higher temperatures.

In order to improve the wear resistance of the surface of such cover plates in particular, so-called scratch-resistant layers are applied to the surface of the cover plate in particular. However, it has been shown that there are still difficulties to obtain coatings which are sufficiently hard and still have sufficient chemical resistance at high temperatures. In addition, the material used for the scratch-resistant layer should also be visually inconspicuous, if possible. This means that they should not distort the color of the light passing through the cover plate if possible and/or have only little absorption if possible, so that, for example, a light indicator (e.g. a display) can be easily observed even at relatively low illumination levels.

Suitable materials for the wear-resistant layer are, for example, metal nitrides or carbides, for example aluminum or titanium nitrides or carbides, or semimetals, for example silicon. However, these materials do not have sufficient chemical resistance for use at high temperatures.

Oxides, in particular metal oxides, are also materials which are at least in principle considered as scratch-resistant layers. They are also very stable materials and some are also transparent or uncolored. However, they are mostly inferior to carbides and nitrides in terms of their mechanical properties, the latter being considerably harder. A disadvantage of some monometallic metal oxides, i.e. metal oxides comprising only one metal as the main metal component, is that they are coloured, for example iron oxide or chromium oxide. On the other hand, titanium dioxide, although colorless, has a very high refractive index and therefore reflects visible light too strongly, which increases the visual conspicuity of such coatings.

As material alternatives, metal mixed oxides, in particular binary or bimetallic oxides, are suitable, for example.

Within the scope of the present invention, metal mixed oxides are understood to mean oxides which comprise a plurality of metal components as main constituents. In other words, the metal mixed oxide includes oxygen ion O as a negative ion or anion^2-And cations of at least two elements, in particular of at least two metals, wherein the second metal comprised by the mixed oxide is not present in doped form or only as an unavoidable trace amount, but is present as an essential component.

Bimetallic or binary metal oxides or mixed oxides are understood here to mean oxides which comprise two metals as main constituents. In particular, the term bimetallic or binary metal oxide or mixed oxide includes compounds having the general formula AB₂O₄An oxide or a mixed oxide of spinel structure. In the context of the present invention, oxides or mixed oxides which are crystalline not only in the spinel structure but also in the inverse spinel structure are encompassed by the term oxides having a spinel structure.

In the spinel structure or in the so-called inverse spinel structure, depending on their size, the metal cations are present in the most closely spherically arranged interstices, which are formed by oxygen ions. The spinel structure (and the so-called inverse spinel structure) is here a crystal structure known to the person skilled in the art and is represented by the mineral spinel MgAl₂O₄And (4) naming.

Spinel MgAl₂O₄Of particular interest is this material, which is resistant up to temperatures above 1000 ℃, in particular it also has sufficient chemical resistance. In addition, it is known that the material can be made transparent even at a thickness of a few centimetersClear and very hard bodies can be obtained from spinel.

Spinel based materials, such as ceramics, are known. For example, the publications Gatti, a., "Development of a process for producing transparent specialty pigment bodies", Final Report, general electric, philadelphia, pa, 1969, describe a method for producing transparencies from spinel.

Furthermore, EP0334760B1 describes a process for producing high-performance objects from magnesium aluminate spinel, in particular those transparent in the infrared and visible.

US patent US4029755A describes transparent ceramics, wherein these ceramics for ceramic processing comprise very small grains with a diameter between 50 μm and 300 μm and are obtained by a cold pressing process.

Black coatings comprising materials with a spinel structure have also been obtained, as described in EP3502075a 1.

However, it has not been possible to obtain transparent, uncolored coatings on cover plates which can be used as scratch-resistant layers. The coating of EP3502075a1 is therefore designed as a pigmented coating and is only of very small thickness of a few hundred nanometers, since, despite the color of the coating being based on absorption, sufficient transmission should ultimately be ensured in the infrared range of the electromagnetic spectrum. However, the coatings of the prior art are therefore unsuitable for use as scratch-resistant layers, in particular as colorless scratch-resistant layers, since the materials according to EP3502075a1 comprise transition metal ions and are therefore always designed to have a unique intrinsic color.

There is therefore a need for a cover plate with a transparent coating which is preferably resistant to mechanical and/or chemical even at high temperatures of up to 1000 ℃, and for a method for producing such a cover plate.

Disclosure of Invention

It is an object of the present invention to provide a cover plate which at least partially overcomes or at least alleviates the previous problems of the prior art.

The object of the invention is achieved by the subject matter of the independent claims. Preferred and/or more specific embodiments can be found in the dependent claims.

The invention therefore relates to a cover plate comprising a glass or glass-ceramic substrate having a first main surface and a second main surface, and a coating arranged on at least one main surface of the glass or glass-ceramic substrate in at least one region of the cover plate, wherein the coating comprises at least one compound of formula a_xB_yO₄Or predominantly (i.e. at least 50 wt.%) or substantially (i.e. at least 90 wt.%) or completely from at least one mixed oxide of formula A_xB_yO₄Wherein the molar ratio of a to B is between at least 0.3 and at most 0.7, wherein the mixed oxide and/or the coating is at least partially crystalline, in particular polycrystalline, and wherein a preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof, and wherein the coating preferably has a light transmission of more than 70%.

Within the scope of the present invention, the following definitions apply:

within the scope of the present invention, a plate is understood to be a shaped body in which the dimensions in one spatial direction of a cartesian coordinate system are at least one order of magnitude smaller than the dimensions in the other two spatial directions perpendicular to the first spatial direction. In other words, the thickness of the shaped body is smaller than its length and width.

Within the scope of the present invention, a main surface of a sheet or more generally of a shaped body is understood to be a surface of a shaped body or sheet which comprises a major area of the surface of the shaped body or sheet. This is particularly the surface of the plate whose dimensions are determined by the length and width of the shaped body. These surfaces are also commonly referred to as the top and bottom surfaces of the board or the front and back surfaces of the board, depending on the exact arrangement of the board.

The embodiment of the cover plate as described above has a series of advantages.

The coating comprises formula A_xB_yO₄Is either predominantly (i.e. more than 50 mol% or atomic%, i.e. based on the molar proportion, respectively) or substantially (i.e. more than 90 mol%) or completely of formula a_xB_yO₄On the other hand, the coating is designed to be stable at high temperatures. A high-temperature-stable design of the coating and/or of the material is to be understood within the scope of the present invention as meaning that no phase change of the material or of the coating occurs at high temperatures, for example at temperatures up to less than 900 ℃, in particular up to 800 ℃. The material or coating also does not exhibit degradation, such as decomposition reactions or crack formation.

By the mixed oxide and/or the coating being at least partially crystalline, very good resistance of the material is advantageously supported or in a corresponding manner also very good resistance of the coating. For example, the mixed oxides can be present in the form of spinel structures or inverse spinel structures or also olivine structures, wherein the presence of a spinel structure or possibly an inverse spinel structure may be advantageous. Since the spinel structure or possibly the inverse spinel structure is a very stable structure from a crystallographic point of view, it is not prone to any phase change. It is therefore particularly advantageous if the coating has a very high crystalline or microcrystalline content. In particular, the material or coating or mixed oxide is polycrystalline.

The advantageous design of the coating can be influenced in particular by the choice of material. Thus, component a preferably comprises iron Fe and/or magnesium Mg and/or beryllium Be and/or zinc Zn and/or cobalt Co and/or silicon Si and/or manganese Mn and/or vanadium V and/or mixtures thereof. The metal forming component a or comprising component a is here preferably present in the form of a cation, which preferably has an oxidation number II +, i.e. is, for example, an alkaline earth metal. However, component a may also be formed from or comprise silicon, a semimetal, which has an oxidation number IV + in the oxygen compound. Furthermore, it is preferred that B comprises aluminum Al, iron Fe, chromium Cr or vanadium V or mixtures thereof, wherein the metals forming or comprising component B are present here in cationic form. It is particularly preferred that the major portion (i.e., at least 50 atomic% or mole%) of A is magnesium, and the major portion (i.e., at least50 atomic% or mole%) is aluminum. In particular, it is also possible that the material or mixed oxide or coating comprises, apart from unavoidable traces, only magnesium and aluminum as metal components or cations thereof, i.e. the material or mixed oxide or coating consists of spinel MgAl₂O₄Particularly polycrystalline spinel formation. It may be advantageous to have a polycrystalline design of the material and/or coating, since if very small, fine crystallites are present, they are optically inconspicuous, since grain boundaries are not perceived as visually disturbing and therefore transparency is not significantly disturbed by such a coating.

Combinations of the following metals are preferred here:

if A comprises magnesium and/or beryllium, B is preferably aluminium and/or iron and/or chromium and/or vanadium.

If B comprises aluminum, A is preferably magnesium and/or beryllium, and/or a mixture of magnesium and/or beryllium and/or vanadium.

If B comprises chromium, A is preferably magnesium and/or iron and/or zinc and/or cobalt.

If B comprises vanadium, A is preferably manganese and/or magnesium.

If B comprises iron, A is preferably magnesium and/or silicon.

According to one embodiment, the coating therefore comprises at least one compound of formula a_xB_yO₄Wherein the molar ratio of A to B is between at least 0.3 and at most 0.7, wherein A comprises magnesium and/or beryllium and B comprises aluminum and/or iron and/or chromium and/or vanadium,

and/or at least one compound of the formula A_xB_yO₄Wherein the molar ratio of A to B is between at least 0.3 and at most 0.7, wherein B comprises aluminum and A comprises magnesium and/or beryllium and/or a mixture of magnesium and beryllium, and/or vanadium,

and/or at least one compound of the formula A_xB_yO₄Wherein the molar ratio of A to B is between at least 0.3 and at most 0.7, wherein B comprises chromium and A comprises magnesium and/or iron and/or zinc and/or cobalt,

and/or at least one compound of the formula A_xB_yO₄Wherein the molar ratio of A to B is between at least 0.3 and at most 0.7, wherein B comprises vanadium and A comprises manganese and/or magnesium,

and/or at least one compound of the formula A_xB_yO₄Wherein the molar ratio of a to B is between at least 0.3 and at most 0.7, wherein B comprises iron and a comprises magnesium and/or silicon.

It is possible here for the coating to comprise only one crystalline phase, for example only crystals or crystallites or from MgAl₂O₄And (4) preparing. This is synonymous with the coating comprising only one mixed oxide or consisting essentially or entirely of only one mixed oxide. However, it is also possible for the coating to comprise a plurality of crystalline phases, that is to say, for example, in addition to MgAl₂O₄In addition, it also includes Fe₂SiO₄And/or another crystalline phase. This is synonymous with the coating comprising, or consisting essentially or entirely of, a plurality of mixed oxides.

Furthermore, it is generally possible that the coating is at least partially amorphous, that is to say comprises an amorphous phase in addition to at least one crystalline phase or possibly also a plurality of crystalline phases.

The formation of a coating comprising only one crystalline phase (or only one mixed oxide) is understood to mean that the coating comprises only crystals or crystallites of a specific crystallographically definable phase. The formation of a coating comprising a plurality of crystalline phases is accordingly understood to mean that different crystalline phases can be detected in the coating in a crystallographic manner, for example by X-ray diffraction (XRD).

Preferred crystalline phases include, for example, MgAl₂O₄，BeAl₂O₄，MgFe₂O₄，MgCr₂O₄，MgV₂O₄，(Be、Mg)Al₂O₄(e.g., BeMgAl)₄O₈)，FeCr₂O₄，ZnCr₂O₄，CoCr₂O₄，FeV₂O₄，Val₂O₄，SiFe₂O₄，MnV₂O₄。

Furthermore, the advantageous development of the coating properties can also be supported by a suitable choice of the molar ratio of components a and B to one another. The molar ratio of components A and B to one another is advantageously in the range between at least 0.3 and at most 0.7. It is particularly possible that the ratio may be exactly 0.5, i.e. one atom a corresponds to two atoms B. In this case, the stoichiometric composition is based on the spinel or inverse spinel structure AB₂O₄And (6) obtaining. However, deviations from this ideal stoichiometric ratio, which may be based, for example, on the changing valences of components A and/or B, may be tolerated within the above-mentioned ranges. In particular, the mixed oxides may generally comprise, in addition to the components A and/or B, the component C, i.e. the mixed oxide A_xB_yO₄In doped form. Since the components A and B determine the basic properties of the mixed oxides, it can still be said that the compounds or mixed oxides A_xB_yO₄. If component C is to be mentioned, the mixed oxide can also be written or designated A in the presence of a doped mixed oxide_xB_yO₄C or A_xB_yC_zO₄. In this context, without being limited to any embodiment of mixed oxides, coatings and/or coverplates, it is generally understood that: depending on the valency and/or amount of each component A, B and/or C, the amount of oxygen O can deviate from the stoichiometric amount given in the formula (i.e., index "4"). However, as long as the crystal structure corresponds to the corresponding stoichiometric compound, this is not considered critical.

Thus having the formula A_xB_yO₄The formation of the oxidic phase of (a) is also particularly advantageous, since in this way wear-resistant coatings, for example scratch-resistant and/or wear-resistant coatings, can be obtained, which have, however, a reduced layer stress compared to known scratch-resistant layers (for example nitrides). Preferably, the amount of layer stress in the coating according to an embodiment is at most 800MPa, preferably at most 500MPa, and particularly preferably at most 300 MPa. In other words, the layer stress is preferably. + -. 800MPa, preferably at most. + -. 500MPa, and in particularPreferably at most. + -. 300 MPa. That is, depending on the precise embodiment, the coating may not only be under tensile stress or may also be under compressive stress. It is thus possible, for example, to coat very thin substrates, for example thin glass, since even thin substrates, which are coated with a coating according to embodiments of the invention, in particular are coated on one side, have only slight curvature or less warpage due to the reduced layer stress.

The lower layer stress of the coating material according to embodiments of the invention is also advantageous during the coating process. Because these coating materials often flake off layers on the inside in the coating unit, for example inside the sputter chamber, on account of the high intrinsic layer stresses in the case of nitrides.

According to one embodiment of the cover plate, the cover plate is designed such that the amount of layer stress in the coating according to an embodiment is at most 800MPa, preferably at most 500MPa, and particularly preferably at most 300 MPa.

The layer stress in oxide systems and/or nitride systems can be influenced by a number of process parameters. In particular, parameters which have an influence on the porosity, the bulk density, the crystallization state and/or the layer structure of the coating play an important role. The parameters "process pressure" and "temperature" are to be mentioned here, among others. Furthermore, the influence of the temperature depends to a large extent on the material applied and its phase change. General rules cannot be deduced in this respect, but due to the influence of temperature on the layer porosity and crystalline state, it can be expected to strongly influence the layer stress as well. Furthermore, due to the cooling process after the coating is performed, differences in the thermal expansion coefficients (e.g. differences in the linear thermal expansion coefficient between the substrate and the layer material) may already induce stresses in the coating.

Process pressure is another important parameter for tuning the layer stress. In most cases, low pressure will result in a reduction of defect sites and growth of a dense layer, which will typically result in an increase in compressive stress. For example, for sputtered Si₃N₄Coating, which can be shown. This is because low process pressures result in very high layer stresses, the highest amount of whichIn excess of 2GPa, as can be seen, for example, in FIG. 8 (see page 158 and below) of Ruske et al, entitled "solid films 351" (this solid films 351) (1999).

In this context, the crystalline state of a coating is generally summarized as a parameter related to the crystallinity of the coating, such as the type, amount and/or size of the crystalline phase comprised by the coating.

Surprisingly it has been shown that a method according to an embodiment of the invention (as will be described in more detail below) may result in a layer having a relatively low layer stress, which brings about the advantages discussed above.

Furthermore, the oxide material comprised by the coating according to embodiments of the present invention has a low refractive index, for example between 1.6 and 1.8, such as 1.7, compared to, for example, nitrided materials or generally known scratch resistant coatings. This is advantageous because in this way the observability of the coating according to embodiments of the invention is low, in particular lower than that of conventional scratch resistant coatings. In particular in cover plates comprising a coloured glass or glass ceramic substrate, or in glass or glass ceramic substrates, on the main surface opposite to the main surface on which the coating is arranged, a further coating is provided which, for example, masks or generally reduces the transparency through the substrate, the coating according to embodiments of the invention being less visually noticeable.

The coating preferably has a light transmission of greater than 70%. The light transmission of the coating is preferably at least 80%, particularly preferably at least 90%. Here, the light transmittance of the uncoated substrate is determined by subtracting the value obtained for the uncoated substrate from the value obtained for the coated substrate, and the light transmittance of the substrate is determined by determining the light transmittance of the substrate in the region in which only the coating is arranged on only one main surface of the glass or glass-ceramic substrate, and the light transmittance of the coating is determined by the difference of these light transmittances. The decrease in transmission determined in this way is due to the coating. The light transmittance produced by the coating at this time is obtained by subtracting the difference determined by the light transmittances of the coated and uncoated substrates, respectively, from 100%, as described above. In this case, the light transmittance of the coated or uncoated substrate is preferably determined for a wavelength range of 380nm to 780nm according or following DIN EN ISO 13468.

For example, the light transmittance of the coated substrate in the region where only the coating layer is disposed on only one main surface of the substrate is 76%, and for the uncoated substrate, the light transmittance is 77%, resulting in a difference in light transmittance of the substrate of 1%. Accordingly, the light transmission of the coating is then 100% minus 1%, i.e. here 99%.

In other words, the light transmittance of the coating is given by the following formula:

LTG (coating) — 100% - (LTG (coated substrate) -LTG (uncoated substrate))

LTG here represents the light transmittance, the light transmittance of a coated substrate being the light transmittance of the cover plate in the area where only the substrate and the coating are arranged. The light transmission of the coated substrate and the light transmission of the uncoated substrate are preferably determined in accordance with or according to DIN EN ISO 13468 for a wavelength range of 380nm to 780 nm.

Such an embodiment having a high light transmission of at least 70% of the coating is advantageous, since in this way the transparency through the coating is not greatly reduced. Therefore, such high light transmission is preferred, especially for applications in viewing windows. However, for applications such as applying a coating to an already coated substrate, embodiments of such a coating as a highly transparent coating are also advantageous. Thus, in this case, other coatings which are "top coats" for the coating according to embodiments of the invention can also be seen clearly, for example, through the coating according to embodiments of the invention. This is particularly advantageous in the case of other coatings, for example in the form of logos.

According to one embodiment of the invention, the coating has a thickness of between 0.05 μm or more and preferably 3 μm or less. Such a minimum layer thickness is advantageous because it improves the mechanical stability of the coating. The mechanical stability of the coating can be the resistance of the coating to wear loads, for example scratching or abrasion. Surprisingly, the advantageous properties of the coating can already be achieved at a layer thickness of 50 nm. The mechanical properties of the coating can be further improved if the thickness of the coating is increased. However, it is particularly advantageous to limit the layer thickness to preferably at most 3 μm. This is because the mixed oxides that may be included in the coating may in some cases have an inherent color. This intrinsic color is formed in particular when the mixed oxides concerned are present as bulk material. However, a different situation may be the case if such a material having an inherent color as a bulk material is present in a thin coating. In this case, the coating may be colored only to a small extent and possibly the inherent color of the mixed oxide cannot be observed at all. Thus, the coating should not be too thick, since thick coatings are not only more visually noticeable than thin coatings, but are also more prone to cracking. In addition, it is uneconomical to produce coatings that are too thick, in particular because thick coatings in the μm range also reduce the breaking strength of the cover plate, for example the impact strength or the bending strength. Therefore, the thickness of the coating is preferably limited. The thickness of the coating is preferably at most 3 μm.

According to another embodiment of the invention, the coating is transparent and uncolored. This is advantageous because the coating is particularly visually unobvious in this way. This not only ensures that the coating preferably only slightly reduces the light transmission through the glass or glass-ceramic substrate, but particularly preferably that, owing to the coating itself, the color location of the light penetrating the glass or glass-ceramic substrate does not shift. In other words, for example, in this way a luminous display, for example a display arranged below or behind such a cover plate and/or without requiring particularly strong luminous power, can be observed in a particularly true-color manner.

With regard to the formation of transparent and uncolored coatings, the optical properties of the coatings can preferably be characterized by comparing the color position of the uncoated glass or glass-ceramic substrate with the glass or glass-ceramic substrate coated with a coating according to an embodiment. Thus, within the scope of the present invention, it is preferred that the color location E of the cover plate is when in a partial region in which only the coating is arranged on only one main surface of the glass or glass-ceramic substrate₁₀₁And glass or glass-ceramics thereinColor location E of the cover plate in the region of the substrate where no coating is arranged₁₁₀When the difference Δ E between these is at most less than 20, preferably less than 15, particularly preferably less than 10, the coating is referred to as transparent and uncolored, wherein the color location E in the partial region is particularly preferably determined in the laxb color system₁₁₀And color location E in the region₁₀₁And the color position difference Δ E is calculated according to the following formula:

wherein the color position E₁₁₀By colour coordinates a₁₁₀、b*₁₁₀、L*₁₁₀Given, and the color location E₁₀₁By colour coordinates a₁₀₁、b*₁₀₁、L*₁₀₁Given, and preferably determined in measurements with respect to white tiles, respectively, in particular using a CM-700d spectrophotometer by Konica-Minolta.

According to another embodiment of the cover plate, the cover plate has a thickness between 2mm and 8mm, preferably between 4mm and 6 mm. This is advantageous because in this way the cover plate has sufficient mechanical strength against breaking loads to be able to be used, for example, as a viewing window in thermal applications or as a so-called cooking plate. The mechanical strength of the cover plate against breaking loads includes the so-called impact strength, which can be determined, for example, in the so-called ball drop test, and the bending strength, which can be determined, for example, in a three-point bending. In order to obtain sufficient strength of the cover plate here, it is advantageous if the cover plate has a minimum thickness of 2mm, preferably at least 4 mm. However, the thickness of the cover plate should not be too high either, since otherwise the material costs are too high on the one hand and the weight of the cover plate is too high on the other hand. It is therefore preferred that the cover plate has a thickness of at most 8mm, preferably at most 6 mm. According to an embodiment, the cover plate may comprise a substrate having a thickness of at least 2mm, preferably at least 4mm, and a thickness of at most 8mm, preferably at most 6 mm.

However, according to another embodiment, the cover plate may also have a thickness of less than 2mm, such as less than 1mm, for example at least 30 μm, such as 50 μm or 100 μm. Thus, in particular, according to one embodiment, the cover plate may comprise a substrate designed as so-called thin glass. In particular, the substrate may also have a thickness of less than 2mm, for example less than 1mm, for example at least 30 μm, for example 50 μm or 100 μm. Such an example can surprisingly be achieved by a coating according to an embodiment, since the layer stresses in a coating according to an embodiment are very small for a so-called hard material layer or scratch-resistant or wear-resistant layer. This is shown in particular on only a slight bending of the cover plate provided with such a coating.

According to a further embodiment of the cover plate, in a partial region of the cover plate or of the glass or glass-ceramic substrate in which only the coating is arranged on only one main surface of the glass or glass-ceramic substrate, the haze of the cover plate, measured according to ASTM-D1003, is less than 5%, preferably less than 2%, and particularly preferably less than 1%.

In other words, in a partial region of the cover plate or of the glass or glass-ceramic substrate in which only the coating is arranged on only one main surface of the glass or glass-ceramic substrate, the cover plate has only a very low haze (haze) or the cover plate is very clearly transparent. In particular, this is also achieved in that the coating itself also has only very low haze or is designed without significant haze. Such a design is advantageous because in this way a particularly good view through the cover plate is ensured, so that, for example, light-emitting elements, such as displays, arranged behind or below the cover plate can be easily seen. Such a design is also advantageous for a viewing window for thermal applications, such as a viewing window of an oven or fireplace.

According to another embodiment of the cover plate, the coating has a hardness of 6 to 11GPa as determined in a measurement method according to or according to DIN EN ISO14577-1 and EN ISO14577-4 (so-called mahalanobis hardness). This design is particularly preferred because in this way the cover plate has a particularly good resistance to wear loads, for example scratching of the surface or wear loads, in the region where the coating is arranged. In other words, according to this embodiment, the cover plate is designed as a wear-resistant, in particular scratch-resistant and/or abrasion-resistant cover plate, at least in the region in which the coating is arranged on the main surface of the glass or glass ceramic substrate. This is particularly important for applications where the cover plate is in contact with abrasive materials and/or objects. Such an embodiment of the cover plate is particularly advantageous, in particular during cleaning of a so-called cooking plate or also of a viewing window for an oven or fireplace, in particular when cleaning work is carried out with a so-called scraper. However, contact with the cooking appliance, for example, may also result in scratches in the surface.

Such a design is particularly advantageous for applications of the cover plate in which frictional loads occur, for example in the case of a cooking plate by the movement of the pan. It is to be noted here that, for example, abrasive particles may also be arranged between the surface of the cooking plate and the cooking utensil, which then additionally produce a wear effect. A design of the cover plate in which the coating also has a wear resistance as described above is therefore particularly advantageous. Since little surface wear results therefrom.

According to a particularly advantageous embodiment of the cover plate, the coating covers the main surface of the glass or glass-ceramic substrate substantially over the entire surface. In the context of the present invention, a substantially full-surface coverage is understood here to mean that the coating covers at least 90%, preferably at least 95%, of the relevant area. This design is particularly advantageous, in particular, when the coating has a high hardness and/or a high abrasion resistance, since in this way the main surface covered with the coating over substantially the entire surface is designed to be particularly abrasion-resistant, for example abrasion-resistant and/or scratch-resistant, over almost the entire surface. A substantially full-surface coating is also understood here to mean embodiments in which the coating according to an embodiment is not arranged directly on one main surface of the substrate, but there is, for example, a layer between the substrate and the coating. The degree of coverage is generally given by the ratio of the area covered by the coating of the main surface to the total surface of the main surface.

According to another embodiment of the cover plate, the cover plate has further coatings. This further coating can be designed, for example, as a glass flow (glasflash) based coating, which is obtained, for example, by printing a so-called enamel and then baking. Glass flow based coatings for cover plates are known. Such coatings are used, for example, as cooking zone markings and/or for marking functional areas. This is particularly important, since the marking of the functional areas is particularly important, for example, in the case of the use as a cover plate of a cooking plate in a so-called induction heater. Since only correct positioning of the cooking appliance ensures that the cooking process can be carried out in the process.

In this case, according to an embodiment of the cover plate, the further coating is arranged on the same main surface of the glass or glass-ceramic substrate as the coating and covers this main surface at least or only partially. The further coating is arranged between the glass or glass-ceramic substrate and said coating. In particular, the further coating preferably adjoins the coating.

This design of the cover plate is advantageous in particular in the case where the further coating itself is not particularly resistant to mechanical and/or chemical. For example, it is known that substances in contact with the cover plate can attack the surface of the cover plate or the glass or glass-ceramic substrate. As mentioned above, this may lead to mechanical wear, such as scratching and/or abrasion of the surface, but certain substances may also chemically react with the surface and degrade it in this way. However, it is also known in particular that coatings, for example coatings based on glass flows, which are applied precisely to the surface of the cover plate and/or the glass or glass-ceramic substrate, are particularly susceptible to mechanical and/or chemical attack. This may be due, for example, to the fact that such glass-flow-based coatings can only establish inadequate adhesion on glass or glass-ceramic substrates, or due, for example, to the fact that the surface of such glass-flow-based pigmented coatings is very rough and therefore provides a large attack surface for both mechanical and chemical attack. In particular in the case of cooking plates, it is also possible, for example, for the food to be baked on the surface of the cover plate which faces the user in operational use, i.e. the top surface, and to form a tight connection with the glass-flow-based colored decorative surface also in the process. During cleaning, which is preferably carried out by means of a so-called doctor blade, it is entirely possible to remove a portion of the decorative surface together with the soiling. This not only causes visual interference, but may also lead to the removal of a large part of the important markings of the functional area.

Therefore, according to one embodiment of the cover plate, it is particularly preferred that a further coating is arranged on the same main surface of the glass or glass-ceramic substrate as the coating and covers it at least or only partially, wherein the further coating is arranged between the glass or glass-ceramic substrate and the coating. In this case, the further coating can be arranged directly on the main surface of the glass or glass-ceramic substrate, i.e. can be in direct contact with the glass or glass-ceramic substrate. This may be advantageous, for example, if a tight connection is to be formed between the material of the glass or glass-ceramic substrate and the further coating (i.e. for example a coating based on glass flow), for example to form a melt reaction zone. However, it is also possible to provide a coating between the further coating and the surface of the glass or glass-ceramic substrate, which coating acts, for example, as an adhesion promoter or barrier layer, for example, to reduce the formation of so-called halos around the glass-flow-based coating.

The coating is advantageously applied to the further coating. For this reason, it is advantageous if the coating adheres well to the further coating, so that no adhesion failure occurs at the interface between the coating and the further coating. Since the coating layer, when applied to the further coating layer, serves as a top coat and as a protective coating for the further coating layer and in this way also improves the mechanical and/or chemical resistance of the further coating layer at the same time.

According to a further embodiment of the cover plate, the glass or glass-ceramic substrate is designed to be transparent and uncolored or transparent and colored. The glass or glass ceramic substrate can be designed not only to be smooth on both sides, but also to be roughened on one side, preferably on the side facing away from the user in operational use. When a good field of view through the glass or glass-ceramic substrate and in a corresponding manner also through the cover plate is required, for example for a viewing window, in particular in the case of a viewing window for thermal applications, it is preferable for the glass or glass-ceramic substrate to be designed to be transparent and uncolored. However, it may also be advantageous to select a transparent and uncolored glass or glass ceramic substrate and to provide the coating with a reduced transparency at least partially on one side, preferably on the side facing away from the user or operator during operational use. Such a design is possible, for example, for the application of the cover plate as a cooking plate, in particular when the display and/or other display elements are also integrated into the cooking appliance, which are arranged below the cover plate or the cooking plate. These display elements can thus be seen particularly clearly in this case, in particular where no absorption of the light of the display elements by the transparent and colored substrate takes place.

However, in particular, not only for use as a cooking surface, it may also be advantageous to design the glass or glass-ceramic substrate to be transparent and colored. In this way, components and/or structures arranged behind or below the cover plate are therefore no longer clearly visible. It is also possible to adjust the transmission of visible light by absorption of a particular color in a glass or glass-ceramic substrate so that certain elements or structures can be observed through the cover plate, but other elements or structures cannot be observed through the cover plate.

Within the scope of the present invention, a transparent and colored design of a glass or glass-ceramic substrate is understood to mean that the glass or glass-ceramic substrate is colored, in particular by colored metal ions. Within the scope of the present invention, this is also understood to be volume coloration. Within the scope of the present invention, a material and/or product, such as a glass or glass-ceramic substrate, is said to be transparent if it is non-scattering. In contrast to transparent designs, there are therefore in particular opaque and translucent designs, where the opacity or translucency is caused by scattering particles in the material or in the product. Thus, in particular, within the scope of the invention, it is possible that the material and/or the product is referred to as transparent despite being absorbent, since in this case no scattering of visible light occurs in this design despite the reduced transmission of visible light in the transmitted light.

According to a further embodiment of the cover plate, the coating is arranged on a main surface of the glass or glass-ceramic substrate, which main surface faces the user when the cover plate is in operational use and is therefore designed as a top or front surface. This is particularly useful when the coating is designed as a hard and/or abrasion-resistant coating, i.e. in particular as a scratch-and/or abrasion-resistant coating. This is because, even on the side facing the user in operational use, a maximum stress on the surface of the cover plate (for example on the top surface of the cooking plate) is usually also produced.

The top or front side of the cover plate generally has a special design. In general, the top or front side of the cover plate is designed to be smooth on the one hand, while the bottom or rear side of the cover plate can also be designed to be roughened, for example. In the case of a cover plate designed as a cooking surface, the top side of the cover plate is usually also covered with further coatings, which, for example, mark functional areas (e.g. cooking areas). Finally, the top surface of the cover plate is also the top surface that determines the strength of the cover plate. That is to say, the mechanical strength of the cover plate against the breaking load is determined, i.e. the top face is the side on which the respective load acts, i.e. for example the side on which the steel ball falls in the ball drop test.

Another aspect of the invention relates to a method for manufacturing a cover plate according to the above-described embodiment. This involves a physical coating process (or PVD, physical vapor deposition). The method comprises the following steps:

-providing a glass or glass-ceramic substrate,

-introducing the glass or glass-ceramic substrate into a coating chamber,

-providing a ceramic or metal target comprising components A and B, wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof,

providing a gas as reactive gas, wherein the gas is preferably oxygen,

-setting a pressure in the coating chamber, wherein the pressure is at least 1 x 10^-3mbar and at most 5 x 10^-2The mbar of the water is between the mbar,

-setting a temperature in the coating chamber of more than 40 ℃, wherein the manufacturing temperature is preferably at most 350 ℃,

coating by vapor deposition or sputtering, wherein the sputtering can be carried out as direct-current sputtering or pulsed sputtering, for example as medium-frequency or high-frequency sputtering,

optionally post-treatment of the coating by further treatment steps in the form of heat treatment in an oven, preferably a ceramization oven, by laser input, by flash lamp treatment, by UV post-treatment, by additionally inputting plasma, for example by means of an oxygen plasma in vacuum or by means of plasma lines in the atmosphere or by applying a flame,

and/or

Optionally adding a further substance in the form of Si or Ti, wherein the proportion of the further substance is less than 10%, preferably less than 5%, particularly preferably less than 2%,

whereby at least one main surface is at least partially coated with a coating comprising a molecule of formula A_xB_yO₄Or predominantly or substantially or completely of the formula A_xB_yO₄The mixed oxide of (a) and (b),

wherein the molar ratio of A to B is between at least 0.3 and at most 0.7,

wherein the mixed oxide and/or the coating is at least partially crystalline, in particular polycrystalline,

wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and

wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof, and wherein the coating preferably has a light transmission of more than 70%.

The coating can be carried out in-line, but the coating can also be carried out in a batch process and therefore not in-line.

As already explained above with regard to layer stress, with the method according to an embodiment of the invention, in particular by coating with the sputtering method according to an embodiment, it is surprisingly possible to obtain a very advantageous design of the coating. Surprisingly, it has been shown that such coatings can be obtained, in particular, by means of sputtering methods, such as pulsed sputtering, in particular preferably pulsed medium-frequency or high-frequency sputtering: the coating is at least partially crystalline, in particular polycrystalline (or the coating comprises an at least partially crystalline, in particular polycrystalline, mixed oxide), and the coating still has a low layer stress. This effect can be enhanced by an additional post-treatment of the coating, either directly in vacuum or in the atmosphere. Another possibility to support this effect is to additionally add at least one further substance which acts as a seed nucleating agent.

The coated sample can be post-treated directly in the coating chamber or after a subsequent coating process. This can occur in different ways:

-carrying out a thermal post-treatment, in particular at atmospheric pressure, at a temperature of at least about 400 ℃, better at least about 500 ℃, more advantageously at least about 600 ℃ or even at least about 900 ℃, but at a temperature not exceeding at most the maximum service temperature 1100 ℃ of the cover plate, for a duration of preferably at least 2 hours, more preferably at least about 4 hours or more, in an optimal case at least about 6 hours, but not exceeding 100 hours. In this way, the coating may be "annealed", which may also be referred to or understood as "annealed" or generally referred to or understood as a thermal post-treatment or heat treatment. For example, the post-treatment may be performed during thermal tempering of the cover plate (in particular in case the cover plate comprises a glass substrate) or during ceramization of the cover plate (in particular in case the cover plate comprises a glass ceramic substrate). The advantages of the thermal after-treatment are, in particular, that it can also be carried out in a step provided in the processing of the cover plate after the coating has been carried out, for example in a thermal tempering or in a ceramization process. That is, in this case, there is no need to separately temper the cover plate, but a thermal post-treatment may also be performed during other process steps. Thus, the heat treatment can advantageously be carried out in a ceramization oven (i.e. during the conversion of the raw glass into glass ceramic) or in a tempering furnace (i.e. during the thermal tempering of the glass substrate);

-treatment with a plasma (such as argon, oxygen, ammonia or hydrogen plasma) at a pressure of at most about 10mbar, preferably at most about 5mbar, particularly preferably at most about 1mbar, but preferably at least 0.001mbar, for at least 5 minutes, preferably at least 15 minutes, particularly preferably at least about 60 minutes, but preferably not more than 10 hours, preferably not more than 5 hours;

-using a xenon flash lamp at least 8J/cm²Preferably at least 20J/cm²Particularly preferably at least 40J/cm²At least one, preferably at least five, particularly preferably ten or more discharges are treated with different energies or energy densities of (a);

-treatment with a UV lamp, for example a UV lamp having a line spectrum, at atmospheric pressure for at least 2 hours, preferably at least 4 hours, particularly preferably at least about 6 hours, but not more than 100 hours, wherein preferably the characteristic line of the line spectrum is at 185nm and/or 254 nm;

-treatment with a laser.

By adding so-called nucleating agents, it is possible to stimulate and/or accelerate crystal growth, for A_xB_yO₄In form, the nucleating agent consists of at least silicon or titanium or a mixture of the two materials. As an alternative or in addition to the post-treatment step, it is therefore also possible to add nucleating agents or additives. The amount of additive should here be kept at a low level so as not to have any negative effect on the physicochemical properties of the coating, but to result in a reduction in the crystallization temperature. For this reason, according to one embodiment, the amount of nucleating agent is less than compound a_xB_yO₄Preferably less than 5%, particularly preferably less than 2%. In this context, the above percentages are based on molar proportions or moles (so-called atomic percentages or molar percentages). In other words, in Compound A_xB_yC_zO₄In (3), z is significantly smaller than the numbers x and y. C here preferably comprises the element titanium or the element silicon or a mixture of these two elements, or consists of the element titanium or the elementElemental silicon or mixtures of these elements.

Additional nucleating agents may be mixed into a and B in the alloy target such that all three elements A, B and C are present in the target, with the proportion of component C being much lower than a or B. As already mentioned, component C can here be formed from titanium or silicon or a mixture of these elements. Due to the small amount of component C, such a three-component alloy target or an alloy target including the three components can be processed almost identically to a two-component target material.

Another possibility is to add a third component C to the plasma by so-called co-sputtering, wherein one target material consists or can consist of components a and B and the second target material consists or can consist of component C. Here, the proportion of atoms or ions provided in component C is significantly lower than the amount of atoms or ions provided by the alloy targets of components a and B. Thus, according to one embodiment, the invention also relates to a method for producing a cover plate, preferably according to one embodiment described herein, comprising the following steps:

-providing a glass or glass-ceramic substrate,

-introducing the glass or glass-ceramic substrate into a coating chamber,

-providing a ceramic or metal target comprising components A and B, wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof,

providing a gas as reactive gas, wherein the gas is preferably oxygen,

-setting a pressure in the coating chamber, wherein the pressure is at least 1 x 10^-3mbar and at most 5 x 10^-2The mbar of the water is between the mbar,

-setting a temperature in the coating chamber of more than 40 ℃, wherein the manufacturing temperature is preferably at most 350 ℃,

coating by vapor deposition or sputtering, wherein the sputtering can be carried out as direct-current sputtering or pulsed sputtering, for example as medium-frequency or high-frequency sputtering,

whereby at least one main surface is at least partially coated with a coating comprising a general formula A_xB_yC_zO₄Or predominantly or substantially or completely from the general formula A_xB_yC_zO₄The mixed oxide of (a) and (b),

wherein the molar ratio of A to B is between at least 0.3 and at most 0.7,

wherein the mixed oxide and/or the coating is at least partially crystalline, in particular polycrystalline,

wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, and

wherein B preferably comprises Al, Fe, Cr, V or mixtures thereof, and wherein the coating preferably has a light transmission of more than 70%.

Furthermore, at least one of the following features is included:

-post-treatment of the coating (2) by a further treatment step in the form of a heat treatment in an oven, preferably a ceramization oven or a tempering oven, by laser input, by flash lamp treatment, by UV post-treatment, by additionally inputting plasma, for example by means of an oxygen plasma in vacuum and/or by means of plasma lines in the atmosphere and/or by applying a flame,

adding further components comprising or consisting of titanium or silicon or a mixture of two elements, wherein the proportion of further components is less than 10%, preferably less than 5%, particularly preferably less than 2%, based on the molar proportion, to obtain a mixture comprising compound A_xB_yC_zO₄Wherein z is significantly less than x and y.

Thus, according to this embodiment, the coating may comprise a nucleating agent. Owing to the small molar proportion of component C in the coating, the general formula A is obtained_xB_yO₄Wherein, due to the small proportion of dopants, the basic properties of the mixed oxide continue to be determined by the main components a and B, for example the crystal structure. In bookWithin the scope of the invention, of the formula A_xB_yC_zO₄Are also understood here as meaning mixed oxides of the formula A_xB_yC_zO₄Provided that the maximum proportion of component C, based on molar proportions, is 10% and, if necessary, less. The molar ratio can also be illustrated by the relationship of the indices x, y and z, wherein the molar ratio (MF) can be calculated according to the following formula:

MF＝z/(x+y+z)。

preferably, in the cover plate obtained by the method according to an embodiment, as described above, the amount of layer stress in the coating according to an embodiment is at most 800MPa, preferably at most 500MPa and particularly preferably at most 300 MPa. In other words, the layer stress is preferably. + -. 800MPa, preferably. + -. 500MPa at the maximum and particularly preferably. + -. 300MPa at the maximum.

It is also surprising here that the coating or the mixed oxide which the coating comprises is present in an at least partially crystalline manner, in particular when it is a mixed oxide which is present in a spinel structure or an inverse spinel structure or an olivine structure. This is because it is well known that the formation of such crystal structures usually requires high temperatures, for example in the case of the manufacture of powders (see, for example, optical material 98(2019), section 2.2, authored by Alhaji et al, where the temperature is at least 1400 ℃, or in journal of the european ceramics society (2019), section 2, authored by Orlinski et al, where a temperature of 1000 ℃ is mentioned, eutectic used here) or in the case of the manufacture of single crystals (see, for example, radiophysical and chemical 177(2020), authored by Takebuchi et al, section 2, where a temperature of 1400 ℃ is mentioned in particular).

Surprisingly, in the method according to the present application, it has been possible to achieve at least partial crystallization in the sputtering chamber at low temperatures of up to 350 ℃, which, in addition, are generally at most used for drying the precursor material (see Orlinski et al, supra).

The invention therefore also relates in particular to a cover plate, in particular according to the above-described embodiments, which is produced or can be produced in a method according to an embodiment of the invention, and to the use thereof.

Drawings

The invention is further explained below with the aid of the figures. In the drawings, like reference numerals designate identical or mutually corresponding features. The attached drawings show that:

fig. 1 to 3 show different embodiments of the cover plate.

Detailed Description

Fig. 1 shows a first embodiment of a cover plate 1 according to the application in a schematic cross-sectional view through the cover plate 1, which is not to scale. The cover plate 1 comprises a glass or glass-ceramic substrate 10 having a first main surface 11 and a second main surface 12 and a coating 2 arranged on one of the main surfaces 11, 12, here the main surface 12. The coating 2 is arranged in at least one region 100 of the cover plate 1 or of the glass or glass-ceramic substrate 10.

Coating 2 comprises formula A_xB_yO₄Is either predominantly (i.e., at least 50 wt.%), or essentially (i.e., at least 90 wt.%), or even entirely, of formula a_xB_yO₄The mixed oxide composition of (1). The molar ratio of A to B is between at least 0.3 and at most 0.7. In particular, the molar ratio may be 0.5. The mixed oxide and/or the coating 2 is at least partially crystalline, in particular polycrystalline. A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof. B preferably comprises Al, Fe, Cr, V or mixtures thereof. The coating 2 preferably has a light transmission of more than 70%.

The region 100 is designed such that only the coating 2 and the glass or glass-ceramic substrate 10 are arranged in this region 100. In other words, the region 100 here forms a partial region 101, in which partial region 101 only the coating 2 is arranged on only one main surface, here the main surface 12. For a further embodiment of the cover plate 1 in fig. 2 in the form of a schematic and not to scale cross-sectional view, such a partial region 101 of the region 100 is also shown by way of example and not to scale. Also shown in fig. 2 are other coatings 3 on the major surface 12 of the glass or glass-ceramic substrate 10.

Preferably, the cover plate 1 is designed such that, in at least a partial region 101 of the region 100, in which only the coating 2 is arranged on only one main surface 11, 12 of the glass or glass-ceramic substrate, in this case on the main surface 12, the cover plate has a light transmission of more than 70%.

In general, however, without being limited to the exemplary embodiment of the cover plate 1 shown here, it is also possible to arrange further coatings 3 on the main surfaces 11, 12 of the glass or glass-ceramic substrate 10, in particular also in the region 100. These further coatings 3 can be arranged, for example, on the same main surface as the coating 2, wherein these further coatings can generally lie below the coating 2 or cover the coating 2. The further coating 3 may be, for example, a conductive track (Leiterbahnen) or a tactile coating or, for example, a coating also based on glass flow or an enamel or enamel coating. In fig. 2, these further coatings 3 are shown to be arranged on the same main surface 12 of the glass or glass-ceramic substrate 10 as the coating 2, wherein these further coatings 3 are here in direct contact with the main surface 12 of the glass or glass-ceramic substrate 10 and are arranged between the glass or glass-ceramic substrate 10 and the coating 2. This arrangement of the coatings can be particularly preferred if the coating 2 is designed to be particularly mechanically stable and/or chemically inert and then further coatings 3 are also to be covered by the coating 2 as a top layer in order to obtain a particularly mechanically and/or chemically resistant surface of the cover plate 1 as a whole.

According to this embodiment, the cover plate further comprises a region 110 in which no coating is formed, but only the glass or glass-ceramic substrate 10 is present. This region is for example marked in fig. 1.

According to a preferred embodiment, the coating 2 has a thickness between above 0.05 μm and below 3 μm. Thinner coatings generally do not have sufficient thickness to sufficiently improve the wear resistance of a surface, e.g., of a glass or glass-ceramic substrate 2, even if the thinner coating comprises a material that is mechanically and/or chemically resistant (e.g., material AB)₂O₄) Or consist essentially or even entirely of such resistant materials. In contrast, coatings with a thickness of more than 3 μm tend to form cracks and, in addition, it takes a long time to deposit such thick coatings, which is no longer economically viableIs advantageous.

It is advantageous if the coating 2 is transparent and uncolored. Since the coating 2 is now visually inconspicuous. It is within the scope of the invention to provide a color location E of the cover plate 1 in a partial region 101 in which only the coating 2 is arranged on only one main surface 11, 12 of the glass or glass-ceramic substrate 10₁₀₁Color location E of the cover plate in the region 110 in which no coating is arranged on the glass or glass-ceramic substrate 10₁₁₀When the difference Δ E between these is less than 20, preferably less than 15, particularly preferably less than 10, the coating 2 is preferably referred to as transparent and uncolored, wherein the color location E in the partial region 110 is particularly preferably determined in the laxb color system₁₁₀And color location E in region 101₁₀₁And the color position difference Δ E is calculated according to the following formula:

wherein, the color position E₁₁₀By colour coordinates a₁₁₀、b*₁₁₀、L*₁₁₀Given, and color location E₁₀₁By colour coordinates a₁₀₁、b*₁₀₁、L*₁₀₁Given, and preferably determined in measurements with respect to white tiles, respectively, in particular using a CM-700d spectrophotometer by Konica-Minolta.

The cover plate 1 preferably has a thickness of between at least 2mm and at most 8 mm. The cover plate is preferably at least 4mm thick. Furthermore, the thickness of the cover plate 1 is preferably at most 6 mm. If the cover plate 1 is designed to be too thin, it does not have sufficient mechanical resistance in terms of fracture properties. In particular, for example the impact strength and/or the bending strength may not be sufficient for example for use as a cooking plate or as a viewing window, in particular for thermal applications. However, if the cover plate 1 is too thick, the cover plate becomes too heavy. It is also possible that the transmission properties are too poor, for example in the IR range and/or in the range of visible light. It is possible, for example, that in the case of a too thick cover plate, which is used, for example, as a viewing window in an oven or a fireplace, the thermal radiation can no longer penetrate sufficiently into the space to be heated. If, for example, the cover plate 1 is used as a cooking plate, it is possible that, in the event of too great a thickness of the cover plate 1, sufficiently rapid cooking can no longer be ensured.

Fig. 3 shows a further schematic and not to scale sectional view through the cover plate 1. The arrangement of the coatings 2 and 3 corresponds here to the arrangement in fig. 2. In contrast to the glass or glass-ceramic substrate 10 in fig. 1 and 2, both main surfaces 11, 12 are designed to be smooth in fig. 1 and 2, where the main surface 11 is not smooth but regularly patterned. Such a design of the cover plate may be advantageous, for example, when a particularly high impact strength and/or bending strength of the cover plate 1 is required. This is because the regular pattern has the effect of increasing the strength, in particular the regular pattern can be arranged on the main surface of the cover plate 1 facing away from the user in operational use, because cracks on the base surface of the regular pattern are less prone to propagate and therefore cannot lead to a breakage of the cover plate as easily as in the case of a smooth base surface.

According to one embodiment of the cover plate 1, the cover plate is designed such that, in a partial region 101 of the cover plate 1 or of the glass or glass-ceramic substrate 10 or of the region 100 of the cover plate 1, in which only the coating 2 is arranged on only one main surface 11, 12 of the glass or glass-ceramic substrate 10, the cover plate has a haze of less than 5%, preferably less than 2%, and particularly preferably less than 1%, measured according to ASTM-D1003. This means that the cover plate in the partial region of the cover plate 1 or of the glass or glass-ceramic substrate 10, in which only the coating is provided on only one main surface 11 or 12 of the glass or glass-ceramic substrate 10, has only a very low haze. The cover plate 1 is therefore very clearly transparent in this partial region 101, so that only little light scattering occurs. This is advantageous for a particularly good view through the cover plate 1.

It is furthermore advantageous to design the cover plate 1 or the coating 2 such that the coating 2 has a hardness of 6GPa to 11GPa as determined in a measurement method according to or according to DIN EN ISO14577 (so-called mahalanobis hardness). Since in this way, in particular when the coating 2 is applied as a top coat to the cover plate, the coating 2 can function particularly well as a wear-resistant coating, i.e. for example to protect the surface of the cover plate from scratches.

Furthermore, according to another embodiment of the cover plate 1, the cover plate is designed such that the coating 2 covers substantially the entire surface of the main surfaces 11, 12 of the glass or glass-ceramic substrate 10, i.e. at least 90%, preferably even at least 95% of the main surfaces. This is particularly advantageous when the coating 2 is designed to be very hard and/or very wear-resistant, since then the surface covered over substantially the entire surface by the coating 2 is designed to be particularly wear-resistant, for example particularly scratch-resistant and/or wear-resistant.

According to a further embodiment of the cover plate 1, the cover plate 1 is designed such that it has a further coating 3. Without being limited to the embodiment of the cover plate 1 shown in the figures, the cover plate may generally comprise a plurality of further coatings 3, for example electrically conductive tracks or further coatings such as masks, in particular also coatings which are arranged as coating 2 on a main surface of a glass or glass-ceramic substrate 10. In particular, however, the coating 3 can be arranged on the same main surface as the coating 2, here on the main surface 12, according to fig. 2 and 3. The further coating 3 covers the main surface at least partially or only partially. In particular, if the further coating 3 is designed as a glass-flow-based coating, in particular as a pigmented glass-flow-based coating, i.e. for example as an enamel coating, the coating 3 is not applied over the entire surface but only partially covers the main surface. For example, in this case, the coating 3 may be applied as a cooking zone mark. It is also possible to apply the coating 3 in the form of a grid to the main surface. This can be particularly advantageous if the main surface is required to have particularly good scratch or abrasion resistance, since this further coating 3, which is designed as a coloured glass-flow based coating, typically has a thickness of a few micrometers and can in this way act as a spacer, for example, between the bottom of the cooking appliance and the main surface of the glass or glass-ceramic substrate. In this case, the further coating 3 is arranged between the glass or glass ceramic substrate 10 and the coating 2. This is advantageous because in this way not only the spacer effect of the further coating 3 is maintained, but also the further coating 3 is covered by the coating 2. This further coating 3 is thus also protected from scratches and/or abrasion by the coating 2, in particular when the coating 2 is designed to be scratch-resistant and/or abrasion-resistant and/or particularly hard.

According to another embodiment of the cover plate 1, the glass or glass-ceramic substrate 10 may be transparent and uncolored or transparent and colored. For certain applications, for example for viewing windows, it may be particularly advantageous here for the glass or glass-ceramic substrate 10 not to have a strong absorption, for example due to metal ions present in the glass-ceramic or glass, by means of which it is colored. In this case, the glass or glass-ceramic substrate 10 is advantageously designed to be transparent and uncolored. For other applications, it may be more advantageous if, for example, it should be difficult to see through, the glass or glass-ceramic substrate 10 is present in a form which is designed to be transparent and colored, for example in the case of the use of the cover plate 1 as a cooking plate.

According to another embodiment of the cover plate 1, the coating 2 is arranged on a main surface 11, 12 which in operational use of the cover plate 1 faces the user and is therefore designed as a top or front surface.

List of reference numerals

1, covering a plate;

10 a glass or glass ceramic substrate;

11. 12 a major surface of a glass or glass-ceramic substrate;

100 area of the cover plate;

101, a partial region of the region 100;

110 uncoated areas of the cover plate;

2, coating;

3 other coatings.