EP3658702A1

EP3658702A1 - Temperable coatings comprising diamond-like carbon

Info

Publication number: EP3658702A1
Application number: EP18739879.7A
Authority: EP
Inventors: Julian Lingner; Jan Hagen; Norbert Huhn; Julie RUFF
Original assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Current assignee: Saint Gobain Glass France SAS
Priority date: 2017-07-26
Filing date: 2018-07-19
Publication date: 2020-06-03
Also published as: US11732363B2; CN110914474A; WO2019020485A1; RU2761278C2; US11401610B2; US20200181780A1; KR20200035285A; US20220325416A1; RU2020108065A; RU2020108065A3

Abstract

The invention relates to a coated substrate, wherein the coating comprises, starting from the substrate in this order: a) a layer of diamond-like carbon (DLC), b) a metal single ply or multi-ply layer, and c) an oxygen barrier layer, wherein the metal single ply or multi-ply layer contains b1) tin, or tin and at least one alloying element for tin, which are unalloyed or alloyed, or b2) magnesium and at least one alloying element for magnesium, which are unalloyed or alloyed. The coated substrate according to the invention protects the DLC layer, as a result of which said layer can be tempered. The coating has good mechanical stability and good ageing resistance before thermal treatment. The use according to the invention of relatively non-reactive materials is advantageous with respect to EHS. The protective layer can easily be removed after the tempering process. Then a DLC coating of exceptional quality and high scratch resistance is obtained.

Description

Temperable coatings with diamond-like carbon

The invention relates to a diamond-like carbon (DLC) coated substrate. More particularly, the invention relates to an improved multilayer coating system comprising a DLC layer for providing heat-treatable DLC layers.

For many applications, it is desirable to provide a substrate surface with improved scratch resistance. For example, points

Soda lime glass does not inherently have a high scratch resistance, but the application of a suitable thin film can markedly improve the scratch resistance of the glass surface.

Thin layers of diamond-like carbon (DLC) for diamond-like carbon are particularly well suited for this and their scratch resistance is well known. There is extensive literature on processes for making DLC coatings.

For example, WO 2004/071 981 A2 describes an ion beam method for depositing DLC layers. CN 105441871 A relates to the preparation of superhard DLC layers by means of PVD and HI PI MS methods. In

CN 1 04962914 A is an industrial vapor deposition apparatus for

Deposition of DLC layers described. Another device for

Preparation of DLC layers is described in CN 203834012 U. J P

201 1068940 A relates to a process for producing abrasion-resistant DLC layers. Furthermore, DE 1 0 2008 037 871 A1 discloses, for example, the

Use of a DLC layer in a plain bearing.

In many applications, however, it is necessary that the product be heat treated or tempered. Since DLC is not thermally stable at temperatures above 400 ° C and standard annealing processes require temperatures of up to 700 ° C, the properties of the DLC coatings deteriorate or even make nonsense, as the DLC coating "burns".

To provide heat-treatable or temperable DLC layers, two main methods are known. The first method relies on Si doping of the DLC layers themselves to provide temperature resistance during heat treatment to improve. In the other method, additional protective and removal layers are used to protect the DLC layer from oxygen (oxygen barrier layers) and thus prevent the burning of the DLC layer during the heat treatment. The protective and removal layers can be removed again after the heat treatment.

Thus, US Pat. No. 7,060,322 B2 describes a coating system in which a glass coating with a DLC layer is provided with a protective layer of optionally doped zirconium nitride. The protective layer can after a

Heat treatment can be removed again.

US 8580336 B2 describes a glass coating with a DLC layer, wherein above the DLC layer a first and a second inorganic layer are arranged, wherein the first layer comprises zinc oxide and nitrogen. A similar

Coating with a tin oxide layer and an optional zinc oxide layer is described in US 200801 82033 A1.

No. 8443627 B2 relates to a glass coating with a DLC layer, wherein a release layer and a barrier layer comprising zinc oxides or zinc suboxides or aluminum nitride are arranged above the DLC layer. The release layer preferably comprises or consists of oxides, suboxides, nitrides and / or subnitrides of boron, titanium boride, magnesium, zinc and mixtures thereof.

The known systems with barrier layers based on substoichiometric zinc oxides prevent the oxidation of DLC layers on glass. Release layers based on magnesium oxides or magnesium suboxides between the DLC layer and the barrier layer facilitated the release after the release

Heat treatment. These layer modifications provide protection for one

underlying DLC layers, which is tempered in this way. However, the oxygen barrier layers must be relatively thick (> 100 nm) in order to achieve satisfactory protection of the DLC layers. Furthermore, the

Removal of the barrier layers after the heat treatment quite tedious and can e.g. require washing with acetic acid solutions. In addition, magnesium suboxide based stripping layers are difficult to handle during the process due to the instability and reactivity of Mg. In particular, it is difficult to store coated glass when further processing

(Heat treatment) only at a later date done so. Also, in the production by sputtering of magnesium, problems may occur Environmental Protection, Health and Safety (EHS, Environment, Health and Safety).

The invention is based on the object to overcome the disadvantages described above in the prior art. In particular, the object is to provide a protective system for substrates provided with DLC layers, which heat treatment or annealing without affecting the DLC layer

allows, whereby production, handling and processing of the

Coating systems before heat treatment, in particular with respect to EHS, and the replacement of the protection system after the heat treatment, is simplified. Furthermore, the protective systems should be stable on storage and the barrier layer for oxygen protection should be as thin as possible.

According to the invention, this object is achieved by a coated substrate

Claim 1 solved. The invention also relates, according to another claim, to a method for producing a heat-treated layer comprising

diamond-like carbon provided substrate. Preferred embodiments of the invention are given in the dependent claims.

The invention thus relates to a coated substrate, the coating comprising starting from the substrate in this order:

a. a layer of diamond-like carbon (DLC),

b. a metallic, single or multi-layer and

c. an oxygen barrier layer,

wherein the metallic, single- or multi-layer b1) tin or tin and at least one alloying element for tin, which are unalloyed and / or alloyed, in particular as a tin alloy, or b2) magnesium and at least one alloying element for magnesium, the unalloyed and / or alloyed, in particular present as a magnesium alloy contains.

It has surprisingly been found that the DLC coating of excellent quality with high scratch resistance after the heat treatment was obtained by the layer system used according to the invention, wherein the protective layer can be easily removed by simply washing with water. In addition, the coatings showed a good

mechanical stability and good aging stability before heat treatment. The EHS situation is significantly improved, especially when compared to magnesium, especially when removing the protective layer. The coated substrate according to the invention thus shows improved stability with respect to handling and storage life before the heat treatment and compared with coated substrates according to the prior art

exceptional protection during heat treatment. The problems with EHS in the manufacture, storage, handling and removal of the protective layer are minimized. Even relatively thin barrier layers provide good protection. Furthermore, the detachment of the oxygen barrier layer with the metallic layer is quick and easy.

The invention is explained below and with reference to the attached figures. I n this shows:

Fig. 1 is a general, schematic representation of the structure of

coated substrates;

Figure 2 is a schematic representation of a coated glass substrate with a metallic, single layer of magnesium as a reference.

Fig. 3 is a schematic representation of a coated, according to the invention

Glass substrates with a metallic, single layer of tin;

Fig. 4 is a schematic representation of a coated according to the invention

Glass substrates with a metallic layer containing magnesium and aluminum layers in an alternating arrangement;

Fig. 5 is a schematic representation of a coated according to the invention

Glass substrate with a metallic layer containing

Magnesium layers and aluminum and / or copper layers in alternating arrangement;

Fig. 6 is a schematic representation of a coated according to the invention

Glass substrates having a metallic, single layer of a magnesium-copper alloy;

The substrate of the coated substrate of the present invention may be any substrate. The substrate is preferably made of ceramic,

Glass ceramic or glass, wherein the substrate is preferably a glass substrate.

Preferred examples of glass are soda lime glass, borosilicate glass or

Aluminosilicate glass. The soda lime glass can be clear or tinted. In a preferred embodiment, the substrate is a glass sheet. The thickness of the substrates, in particular of the glass substrates, can vary within wide ranges, wherein the thickness z. B. may be in the range of 0, 1 mm to 20 mm.

The coating of the coated substrate according to the invention comprises, starting from the substrate, in this order: a) a layer

diamond-like carbon (DLC), b.) a metallic, single or multilayered layer and c.) an oxygen barrier layer. Of the three layers, the layer of diamond-like carbon is closest to the substrate. The metallic, single or multi-layer is over the layer

diamond-like carbon arranged and the oxygen barrier layer is disposed over the metallic, single or multilayered layer.

It should be generally understood that the following information on the coated substrate refers to the coated substrate prior to heat treatment, unless expressly stated otherwise. A heat treatment can lead to changes, in particular with regard to the metallic layer and the oxygen barrier layer.

Layers of diamond-like carbon are well known.

Diamond-like carbon is usually abbreviated to DLC (for "diamond-like carbon"). The layers of DLC are also referred to below as DLC layers. I n DLC layers is hydrogen-free or

hydrogen-containing amorphous carbon is the predominant constituent, wherein the carbon may consist of a mixture of sp ³ and sp ² -hybridized carbon, optionally sp ³ hybridized carbon or sp ² -hybridized carbon may predominate. Examples of DLC are those with the

Designation ta-C and a: C-H. A DLC layer may also contain foreign atoms, such as. As silicon, metals, oxygen, nitrogen or fluorine, as doping. The DLC layer used according to the invention can be doped or undoped.

The person skilled in the art knows various methods for producing DLC layers. DLC layers are typically applied to the substrate by a vapor deposition process, e.g. B. by physical vapor deposition (PVD, physical vapor deposition), z. As by evaporation or sputtering, or by chemical vapor deposition (CVD, chemical vapor deposition). Preferably used deposition methods are plasma enhanced CVD (PECVD, plasma enhanced CVD) and ion beam deposition. As precursors for the

can be deposited in the PECVD method z. B. Hydrocarbons, in particular alkanes and alkynes, such as C2H2 or CH4, are used.

In a particularly preferred embodiment of the invention, the DLC layer is formed by means of the so-called magnetron PECVD method, also as

magnetron-supported PECVD method, deposited. In which

Magnetron PECVD is a PECVD process in which the plasma is generated by a magnetron or a magnetron target. The coating of the substrate, optionally with one or more

Ion diffusion barrier layers is precoated, takes place in a vacuum chamber in which a provided with the target magnetron and the substrate are arranged. I n the vacuum chamber is under vacuum, z. At a pressure of 0.1 μbar to 10 μbar, at least one reactant gas is introduced into the plasma generated by the magnetron target, whereby fragments of the reactant gas are formed, which are deposited on the substrate to form the DLC layer. The

Reactant gas may, for. As hydrocarbons, especially alkanes and alkynes, such as. As C2H2 or CH4, or organosilicon compounds, eg. Tetramethylsilane. Optionally, additional inert gases, such as. As argon, to

Supporting the plasma are introduced into the vacuum chamber. The

Magnetrontarget can z. B. of silicon, which optionally with one or more elements, such as. As aluminum and / or boron, doped, or titanium. In a particularly preferred embodiment, the magnetron PECVD method is operated so that the magnetron target is in the poisoned mode during DLC deposition. The skilled person is the operation of such methods in the state of target poisoning known and he can

Set process parameters accordingly without further notice. The production of the DLC layer by means of the magnetron PECVD method is advantageous since it allows substrates to be coated over a large area and with good process stability with DLC, without the need for intensive heating of the substrate. The layers thus produced have excellent scratch resistance and good optical properties, especially when the process is operated in the mode of target poisoning.

In a preferred embodiment, the DLC layer has a layer thickness of 1 nm to 20 nm, preferably from 2 nm to 10 nm, particularly preferably from 3 nm to 8 nm. These layer thicknesses are advantageous because it ensures high transparency of the layers. The metallic, single or multilayer coating contains b1) tin or tin and at least one alloying element for tin which is unalloyed and / or alloyed, in particular as a tin alloy, or b2) magnesium and at least one alloying element for magnesium which is unalloyed and / or alloyed, in particular present as a magnesium alloy. The alloying elements for tin or for

Magnesium is usually metals and / or semimetals.

The metallic, single-layer or multi-layer layer used according to the invention has the advantage that it is more stable than conventional layers. The problems with EHS are reduced. In addition, this layer is easier and faster to remove than conventional layers.

In a particularly preferred embodiment, the metallic layer comprises one or more layers of tin, wherein the metallic layer, one or more layers, particularly preferably consists essentially of tin or consists of tin. In this embodiment, the metallic layer is usually single-layered.

In another embodiment, the metallic, single or multi-layer layer contains tin and at least one alloying element for tin. Tin and the at least one alloying element for tin may be unalloyed and / or alloyed. In general, it is advantageous if tin and the at least one

Alloy element present as a tin alloy. This usually simplifies the manufacturing process. However, it has been found that metallic layers in which tin and the at least one alloying element for tin are not as

Tin alloy present, z. B. in the form of alternately arranged layers of tin and layers of the at least one alloying element, properties

which may be quite similar to that of a corresponding tin alloy. Since the layers are very thin, there are relatively large contact surfaces between tin and the at least one alloying element. One also speaks of

so-called pseudo alloys.

Suitable alloying elements for tin are all customary alloying metals known to the person skilled in the art. For example, the at least one

Alloy element for tin may be selected from antimony, copper, lead, silver, I ndium, gallium, germanium or a combination thereof. Particularly preferably, the at least one alloying element for tin is selected from copper, silver, iodine or a combination thereof. If that is at least one

Alloying element is selected from the above-mentioned particularly preferred, may optionally additionally at least one other Alloying element from the aforementioned non-preferred examples may or may not be included.

The tin alloy may, for. B. be a binary or ternary alloy. It may also be a polynary alloy of four or more elements.

Accordingly, in the presence of tin and the at least one

Alloy element for tin, one, two, three or more alloying elements for tin contained.

In a further preferred embodiment, the metallic, single or multilayer coating contains magnesium and at least one alloying element for

Magnesium. Magnesium and the at least one alloying element for

Magnesium can be unalloyed and / or alloyed, in particular as

Magnesium alloy present. In general, it is advantageous if magnesium and the at least one alloying element are present as magnesium alloy. This usually simplifies the manufacturing process. It is in particular

advantageous that as a target, z. For example, for sputtering, a magnesium alloy (eg, with Al and / or Cu) can be used because the alloy reduces the reactivity of pure magnesium targets, which is advantageous in terms of EHS. This also applies analogously to the coatings produced.

However, it has been found that metallic layers in which magnesium and the at least one alloying element for magnesium are present in unalloyed form, for. B. in the form of alternately arranged layers of magnesium and from the at least one alloying element, have properties that may be quite similar to that of a corresponding magnesium alloy. Since the layers are very thin, there are relatively large contact surfaces between magnesium and the at least one alloying element. One speaks here also of so-called pseudo-alloys.

Suitable alloying elements for magnesium are all customary alloying metals known to the person skilled in the art. For example, the at least one alloying element for magnesium may be selected from aluminum, bismuth,

Manganese, copper, cadmium, iron, strontium, zirconium, thorium, lithium, nickel, lead, silver, chromium, silicon, tin, rare earths such as gadolinium or yttrium, calcium, antimony or a combination thereof. Particularly preferably, the at least one alloying element for magnesium is selected from aluminum, manganese, copper, silicon or a combination thereof, with aluminum and / or copper being particularly preferred. If the at least one alloying element is selected from the above-mentioned particularly preferred, may optionally additionally contain at least one further alloying element from the aforementioned non-preferred examples or not.

In general, it is preferable that the alloying element for magnesium (when an alloying element is used) or at least one alloying element for magnesium (when two or more alloying elements are used) is a metal having a higher standard electrochemical potential than Mg or a semimetal. Examples of a metal with a higher electrochemical

Standard potentials as Mg are the abovementioned alloying elements aluminum, bismuth, manganese, copper, cadmium, iron, zirconium, nickel, lead, silver, chromium and tin. Examples of semimetals are silicon and antimony.

The magnesium alloy may, for. B. be a binary or ternary alloy. It may also be a polynary alloy of four or more elements.

Accordingly, in the presence of magnesium and the at least one magnesium alloying element, one, two, three or more magnesium alloying elements may be included.

In a preferred embodiment, the metallic, single- or multilayer coating contains tin, a tin alloy or a magnesium alloy, in particular tin or a magnesium alloy, the metallic layer preferably being single-layered. A preferred magnesium alloy contains as alloying elements aluminum and / or copper, i. E. a Mg-Al alloy, a Mg-Cu alloy or a Mg-Al-Cu alloy, which may optionally contain one or more other alloying elements for magnesium in these alloys.

In a preferred embodiment, the metallic layer is formed from two, three or more layers, wherein one or more layers containing or consisting of tin and one or more layers containing or consisting of at least one alloying element for tin, preferably selected from copper, silver and / or I ndium, are arranged alternately.

In a particularly preferred embodiment, the metallic layer is formed from two, three or more layers, wherein one or more layers containing or consisting of magnesium and one or more layers containing or consisting of at least one alloying element for magnesium, preferably selected from aluminum and or copper, are arranged alternately. An alternating arrangement is understood to mean that one or more layers containing tin or alternatively magnesium (layer a) and one or more layers containing at least one alloying element for tin or magnesium (layer b) are arranged alternately, it being immaterial is which layer is applied first, the order of the position is therefore eg: a / b; b / a; a / b / a; b / a / b; a / b / a / b; b / a / b / a / b etc. The layers containing at least one alloying element for tin or magnesium (layer b) may each contain the same alloying element (s), but different alloying elements may also be present in these layers. If it contains two or more alloying elements, the alloying elements may also be included as an alloy.

For the preferred embodiment, magnesium and an alloying element selected from aluminum and / or copper are given by way of illustration further exemplary alternating arrangements (see also Figures 4 and 5): Mg / Al; Mg / Al / Mg; Al / Mg / Al / Mg / Al; Cu / Mg / Cu / Mg / Cu; Al / Mg / Cu / Mg / Al;

Al + Cu / Mg / Al + Cu / Mg / Al + Cu.

The metallic layer may be formed from one layer. If the metallic layer is formed from two or more layers, z. B. two, three, four, five or more layers may be included. It can z. B. up to 40, preferably up to 20 layers. The thickness of the individual layers may be the same or different. The thickness of a single layer in a multilayer metallic layer may, for. B. in the range of 0.5 nm to 20 nm, preferably 1 nm to 12 nm.

In a preferred embodiment, the metallic, single-layer or multi-layer layer as a whole has a layer thickness of 1 nm to 50 nm, preferably 2 nm to 40 nm, more preferably 4 nm to 25 nm, most preferably 5 nm to 20 nm , on.

In a preferred embodiment based on tin, the proportion of b1) tin or tin and at least one alloying element for tin in the

metallic, single or multilayer z. In the range of 90 atomic% to 100 atomic%, preferably 95 atomic% to 100 atomic%, more preferably 98 atomic% to 100 atomic%, particularly preferably 99 atomic% to 100 Atomic%, ie. the metallic layer consists essentially or consists of tin or tin and at least one alloying element for tin, in the latter case tin and the at least one alloying element for tin unalloyed or alloyed, in particular as

Tin alloy, is present. In a preferred embodiment based on magnesium, the proportion of b2) magnesium and at least one alloying element for magnesium in the metallic, single or multilayer coating z. In the range of 90 atomic% to 100 atomic%, preferably 95 atomic% to 100 atomic%, more preferably 98 atomic% to 100 atomic%, particularly preferably 99 atomic% to 100 Atomic%, ie. the metallic layer consists essentially or consists of magnesium and at least one alloying element for magnesium, in the latter case magnesium and the at least one alloying element for magnesium being unalloyed or alloyed, in particular as magnesium alloy.

The metallic layer preferably consists essentially of metals and / or metal alloys and optionally semimetals. Other connections such. B. metal oxides are preferably not or only in small amounts, eg. B. as

Impurities, e.g. in amounts of less than 5 wt .-%, preferably less than 2 wt .-% and preferably less than 1 wt .-%.

In a preferred embodiment based on tin, in which the metallic layer b1) contains tin or tin and at least one alloying element for tin, the proportion of tin in the metallic, monolayer or multilayer layer is in the range from 50 atom% to 100 atomic%, more preferably 60 atomic% to

100 atomic%, more preferably from 70 atomic% to 100 atomic%, still more preferably from 70 atomic% to 100 atomic%, still more preferably from 80 atomic% to 100 atomic%, and especially 90th Atom% to 1 00 atom%.

In a preferred embodiment based on magnesium, in which the metallic layer b1) contains magnesium and at least one alloying element for magnesium, the proportion of magnesium in the metallic, monolayer or multilayer layer is in the range from 50 atomic% to 99 atom -%, more preferably from 60 at% to 95 at%.

The metallic, monolayer or multilayer can be deposited on the substrate or the substrate provided with the DLC layer by means of well-known methods or vapor deposition methods, preferably by sputtering, co-sputtering or ion beam evaporation.

Even alloys can z. B. sputtered with a target of the corresponding alloy easily. The sputtering can also be carried out, for example, in such a way that it is deposited on the substrate in alternating or alternating sequence of different targets, with which even very thin layers (eg 1 -2 nm) are deposited thick) of different materials can be applied alternately and a mixing of the materials is achieved (pseudo alloy). The alternating sputtering can be achieved, for example, by alternately positioning the substrate and / or the targets. Such operation is common

Deposition devices readily possible.

In co-sputtering, two or more different targets, e.g. two targets of a different metal, under one particular

Tilt angles are deposited so that the materials of the

Mix as homogeneously as possible with different targets on the substrate.

The metallic layer serves as a release layer, as it passes through the

Heat treatment or annealing a simple replacement of the

Oxygen barrier layer is made possible together with the metallic layer by a washing process.

The coating of the coated substrate of the invention further comprises an oxygen barrier layer. The oxygen barrier layer protects the DLC layer, especially from the ambient oxygen. The

Oxygen barrier layer makes it possible to subject the substrate with the DLC layer thereon to a heat treatment or annealing, without resulting in a partial or complete degradation of the DLC layer.

Such oxygen barrier layers and their formation are well known in the art. It can be used for this, the common materials.

For the application of the oxygen barrier layer, the usual methods or vapor deposition methods can be used, for. B. PVD, in particular sputtering, preferably magnetron sputtering, CVD and atomic layer deposition (ALD, atomic layer deposition).

In a preferred embodiment, the oxygen barrier layer comprises or consists essentially of a material selected from silicon carbide, silicon nitride, silicon oxynitride, metal nitride, metal carbide or a combination thereof, wherein silicon nitride, metal nitride, metal carbide or a

Combination thereof are particularly preferred. For the metal nitrides and

Metal carbides, the metal z. As titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten. In a particularly preferred embodiment, the oxygen barrier layer essentially comprises or consists of silicon nitride, in particular S 13N4 and / or doped S 13N 4, with S 13N 4 doped with Zr, Ti, Hf and / or B being particularly preferred and Zr-doped S 13N 4 being most preferred is preferred. With the exception of B, the proportion of doping elements, in particular of Zr, Ti and / or Hf, in the doped S 13N4 z. B. in the range of 1 atomic% to 40 atomic%. The proportion of B as a doping element can, for. B. in the range of 0, 1 ppm to 100 ppm.

The combination of the above-explained metallic layer with a silicon nitride-containing oxygen barrier layer enables a particularly good protection of the DLC layer, in particular when doped S 13N4, preferably Zr-doped S 13N4, is used for the oxygen barrier layer. This is advantageous since in this way already a relatively thin oxygen barrier layer, for. B. with a thickness of not more than 1 00 nm or even significantly lower, a

provide adequate protection. This reduces the manufacturing costs and is also advantageous in terms of a simplified detachment of the layers after the heat treatment.

The term "consisting essentially of" as used herein with respect to the oxygen barrier layer is understood to mean that said material is in particular at least 90% by weight, preferably at least 95% by weight,

more preferably at least 98% by weight forming the oxygen barrier layer.

The oxygen barrier layer preferably has a layer thickness of from 10 nm to 100 nm, preferably from 20 nm to 80 nm, particularly preferably from 30 nm to 80 nm.

In a further preferred embodiment, the proportion of tin and magnesium in the oxygen barrier layer is in each case less than 10 atom%, preferably less than 5 atom% and in particular less than 2 atom%. This also applies to the areas of tin and magnesium mentioned and / or preferred in this application.

In a further preferred embodiment, in the case of a metallic, single-layer or multi-layer with a content of tin of greater than or equal to 50 atomic% (and thus also for all the ranges mentioned and / or preferred), the oxygen barrier layer contains a proportion of tin or of magnesium of less than 10 atom%, preferably less than 5 atom% and in particular less than 2 atom%. In a further preferred embodiment, in the case of a metallic, mono- or multilayered layer with a proportion of magnesium of greater than or equal to 50 atomic% (and thus also for all the ranges mentioned and / or preferred), the oxygen barrier layer has a proportion of magnesium or to tin of less than 10 atom%, preferably less than 5 atom% and in particular less than 2 atom%.

In an optional and preferred embodiment, the coating further comprises one or more of the substrate and the DLC layer

ion diffusion barrier layers. In particular, the ion diffusion barrier layer prevents unwanted diffusion of ions, such as sodium ions, from the substrate into the coating, especially during the heat treatment.

Such ion diffusion barrier layers and their formation are well known in the art. It can be used for this, the common materials. For the application of ion diffusion barrier layers, the usual methods or vapor deposition methods can be used, for. B. PVD, in particular sputtering, preferably magnetron sputtering, CVD or ALD.

In a preferred embodiment, the ion diffusion barrier layer comprises a material selected from silicon carbide, silicon oxide, silicon nitride,

Silicon oxynitride, metal oxide, metal nitride, metal carbide, or a combination thereof, or consisting essentially thereof, with S 13N4 and / or doped S 13N4 being preferred and Zr, Ti, Hf, and / or B doped S 13N4 being particularly preferred. In the metal oxides, metal nitrides and metal carbides, the metal z. For example, titanium, zirconium, hafnium, vanadium, N iobium, tantalum, chromium, molybdenum or tungsten.

The term "consisting essentially of" as used above with regard to the ion diffusion barrier layer is understood to mean that said material is in particular at least 90% by weight, preferably at least 95% by weight,

more preferably at least 98% by weight forming the ion diffusion barrier layer.

The ion diffusion barrier layer has z. B. a layer thickness of 1 nm to 100 nm, preferably from 5 nm to 50 nm, on.

A particularly preferred embodiment is a coated substrate in which the metallic single-layer or multi-layer contains tin or is a tin layer which contains or essentially consists of oxygen barrier layer S 13N4 and / or doped S 13N4, in particular Zr-doped S 13N4 , and if necessary at least one between the substrate and the DLC layer

Ion diffusion barrier layer is arranged, the S 13N4 and / or doped S 13N4, in particular Zr doped S 13N4 contains or consists essentially thereof.

A further preferred embodiment corresponds to that mentioned above, except that the metallic, single or multilayered layer instead of tin

Magnesium alloy, in particular a magnesium alloy with Al and / or copper, contains or consists essentially thereof. Alternatively, the

metallic, single or multilayer coating instead of the magnesium alloy magnesium and at least one alloying element for magnesium, in particular Al and / or copper, in unalloyed form, in particular not as magnesium alloy.

In a further advantageous embodiment, the substrate and in particular the glass substrate, together with the layer of diamond-like carbon and one or more optional ion diffusion barrier layers, are transparent, that is to say they are transparent. the

Visible light transmission is more than 50%, preferably more than 70%, and more preferably more than 80%.

The invention further relates to a process for producing a heat-treated substrate having a coating comprising a layer of diamond-like carbon, comprising: a. Heat treatment of a coated substrate according to the invention as described above, and

b. Removing the oxygen barrier layer and the metallic, on or

multilayered layer of the heat-treated coated substrate by a washing process.

The heat treatment may be annealing. The heat treatment or annealing, e.g. for a glass substrate, e.g. at a temperature of 300 ° C to 800 ° C, preferably 500 ° C to 700 ° C, more preferably 600 ° C to 700 ° C, are performed. The duration of the heat treatment varies depending on the system being treated and the temperature used, but may be e.g. 1 min to 10 min.

For the washing process, as washing medium, e.g. Water, acids, alkalis and organic solvents are used, with water being preferred. The washing process can, for. B. by rinsing with the washing medium, by washing under the action of brushes or preferably by immersion in the

Washing medium done. The washing process can be carried out at ambient temperature (eg in the range of 1 5 ° C to 30 ° C). The washing medium can optionally also be heated. I usually can

Oxygen barrier layer and the metallic layer can be easily removed by simply immersing in a water bath.

The inventive method is suitable for efficient and safe

Preparation of a heat-treated, provided with a DLC layer

Substrate. Due to the relatively non-reactive metallic layer, the risk to the product, plant and workers is reduced. Furthermore, the metallic layer and the oxygen barrier layer can be peeled off quickly and easily.

The invention is described below by way of non-limiting

Embodiments further explained with reference to the accompanying drawings. The figures are schematic drawings, proportions are not taken into account.

Fig. 1 shows schematically a structure of coated substrates according to the invention. The substrate 1 may, for. Example, a glass, a glass ceramic or a ceramic, preferably glass, in particular a glass sheet. On the substrate 1, an optional ion diffusion barrier layer 5 is applied. The

Ion diffusion barrier layer 5 is z. B. of silicon nitride, preferably doped

Silicon nitride formed. On the ion diffusion barrier layer 5 is a DLC layer 2. On the DLC layer 2 is a metallic layer 3. The metallic layer 3 may be constructed in one or more layers (not shown). It can be z. B. to a layer of tin or a magnesium alloy, for. B.

Mg / Cu or Mg / Al, act. Alternatively, the metallic layer 3 of

Magnesium and at least one alloying element for Mg, z. B. AI and / or Cu exist. On the metallic, single or multilayer layer 3 is a

Oxygen barrier layer 4 attached. The oxygen barrier layer 4 is z. B. silicon nitride, preferably doped silicon nitride formed.

This coating system can be heat treated or tempered even at high temperatures without affecting the quality of the DLC layer. After the heat treatment, the no longer needed

Oxygen barrier layer 4 and the metallic layer 3 in a simple manner, for. B. by immersion in a water bath, are replaced.

Examples

Four coated substrates were prepared on a laboratory scale. The

Layer structure of Example 1 is shown in FIG. The layer structure of Example 2 is shown in FIG. The layer structure of Example 3 is shown in FIG. The layer structure of example 4 is in FIG. 5

reproduced.

Example 1 is a reference example. Examples 2 to 4 are examples according to the invention.

In all examples, the DLC layer was applied by a PECVD method (e.g., C2H2 precursor for DLC). The other layers were applied to the substrate by a PVD (magnetron sputtering) process, using the following process parameters for each layer. Alternating layers of different metals were obtained by sputtering alternating with different targets.

Example 1 (reference)

The structure of the coating produced in Example 1 is shown schematically in FIG. The substrate ("glass") is a soda-lime glass having a thickness of about 2.1 mm. Alternatively, as in the following examples 2 to 4, a soda lime glass with a thickness of about 3.9 mm was also investigated here. On the

Glass substrate is an ion diffusion barrier layer ("Si3N4") of S13N4 applied. The thickness of the ion diffusion barrier layer is 20 nm. Above this is a layer of diamond-like carbon ("DLC") having a thickness of 3 nm to 8 nm. This is followed by a metallic layer of magnesium ("Mg") having a thickness of 10 nm. The oxygen barrier layer ("Si3N4") is formed on the magnesium layer. It consists of S13N4 and has a thickness of 50 nm.

Example 2

The structure of the coating produced in Example 2 is shown schematically in FIG. The substrate ("glass") is a soda-lime glass having a thickness of about 2.1 mm. On the glass substrate, an ion diffusion barrier layer ("Si3N4") is made S 13N4 applied. The thickness of the ion diffusion barrier layer is 20 nm.

Above this is a layer of diamond-like carbon ("DLC") with a thickness of 3 nm to 8 nm. This is followed by a metallic layer of tin ("Sn") having a thickness of 10 nm. The oxygen barrier layer ("SisIV") formed on the tin layer and consists of S 13N4 and has a thickness of 50 nm.

Example 3

The structure of the coating produced in Example 3 is shown schematically in FIG. The substrate ("glass") is a soda-lime glass having a thickness of about 2.1 mm. On the glass substrate, an ion diffusion barrier layer ("SisIV") of S 13 N 4 is applied, and the thickness of the ion diffusion barrier layer is 20 nm.

Above this is a layer of diamond-like carbon ("DLC") with a thickness of 3 nm to 8 nm. This is followed by a three-layer metallic layer, which is formed alternately from magnesium and aluminum. The metallic layer begins with a 2 nm thick layer ("Al") of aluminum, followed by a 1 0 nm thick layer ("Mg") of magnesium, followed by another 2 nm thick layer ("AI") made of aluminum , Above this there is an oxygen barrier layer ("S i3N4") consisting of S 13N4 and having a thickness of 50 nm.

Example 4

The structure of the coating produced in Example 4 is shown schematically in FIG. The substrate ("glass") is a soda-lime glass having a thickness of about 2.1 mm. On the glass substrate, an ion diffusion barrier layer ("Si3N4") of S 13N4 is applied. The thickness of the ion diffusion barrier layer is 20 nm.

Above this is a layer of diamond-like carbon ("DLC") with a thickness of 3 nm to 8 nm. Two variants were tested for the metallic layer. In one variant, Mg and Al were used and in the other variant Mg and Cu. From this, a multilayer metallic layer was formed, each alternately made of magnesium and aluminum or alternately

Magnesium and copper are formed. The metallic layer begins with a layer ("Mg") of magnesium, followed by a layer ("Al / Cu") of aluminum or copper, followed by a layer ("Mg") of magnesium, etc. FIG not all applied layers are shown, which is illustrated by. The metallic layer is terminated by a layer of magnesium (not shown). All layers of the metallic layer have a thickness of about 2 nm. The

Total thickness of the metallic layer is about 20 nm. It follows that the metallic layer consists of about 1 0 alternating layers. Above the metallic layer is an oxygen barrier layer ("SisIV"), which consists of S 13N4 and has a thickness of 50 nm.

Alternatively, it would be conceivable to form a metallic layer of Mg, Al and Cu. For this purpose, e.g. an alternating layer sequence Mg / Al / Mg / Cu / Mg / Al, etc. can be selected. In another variant, Cu and Al could be taken together, e.g. be applied as an alloy, which z. For example, the following layer sequence would result: Mg / Cu + Al / Mg / Cu + Al, etc.

Evaluation of Examples 1 to 4

The coatings of all examples showed good temperability and a

exceptionally good scratch resistance after heat treatment and removal of the metallic layer and the oxygen barrier layer. The DLC layer could therefore be protected against degradation and oxidation by the oxygen barrier layer of S 13N4 in all examples.

In particular, oxygen barrier layers of S 13N4 doped with Zr showed excellent protection for the DLC layer during annealing.

After a heat treatment, the metallic layers of the proved

Examples 2, 3 and 4 (Sn or Mg and Al or Cu) advantageously as fracture or

Separation point. Only one treatment with water was required to remove the layers above the DLC layer.

Furthermore, the metallic layers of Examples 2, 3 and 4 (Sn or Mg and Al or Cu) exhibited good mechanical stability prior to annealing, which facilitates processing and storage of the glass which has not yet been heat treated.

The following table shows the relative behavior of the coated substrates of Examples 1 to 4 in terms of storage stability, EHS risk and scratch resistance ("-" = unsatisfactory, "o" sufficient; "+" = good)

Testing the storage stability The coated glass substrates of Examples 1 to 4 were stored after the preparation (without annealing) for eight weeks under atmospheric conditions and examined for signs of aging.

Example 1 then showed poor film adhesion and corrosion, the coating could be removed by merely rubbing with the finger. Example 4 occasionally showed areas where similar adhesion problems occurred. For examples 2 and 3 none of these weaknesses could be identified.

In Example 1, the degradation effect of moisture during storage is clearly shown. While shortly after preparation of the coating, Example 1, similar to Example 2, shows good adhesion and protection behavior, ablation of the coating after 2 months of storage reveals partial exposure of the DLC layer. In this condition, a heat treatment is no longer possible because there is no longer sufficient protection for the DLC layer.

Coatings according to Example 1 are therefore only useful if the

Heat treatment is carried out shortly after preparation of the coating.

In contrast, in the coating of Example 2, even after 2 months none

Detachment of the coating visible and offers much better storage and handling properties.

EHS risk

EHS risk includes an assessment of the EHS hazard situation for the

Production and handling of the coated substrates. As metallic

Magnesium has a certain reactivity, this must always be taken into account, especially in the sputtering process, where fine dusts are formed (Example 1). Combining with less reactive materials (AI / Cu) reduces the risk (Examples 3 and 4). This risk is essentially eliminated in Example 2, since Sn is significantly less reactive than Mg.

scratch resistance

The DLC-coated substrates obtained from Examples 1 to 4 after annealing and after removal of the metallic layer showed good resistance to scratches in a load-bearing test as compared to uncoated soda-lime glass.

For this purpose, balls with a diameter of 1 0 mm stainless steel, borosilicate and alumina with increasing force (even increase in force from 0 N to 30 N by increasing the drop height, speed 30 N / min) on the coated substrates and for comparison act on uncoated soda-lime glass. The stainless steel ball did not leave scratch marks on any of these samples. The spheres of borosilicate and aluminum oxide have left a depth of at least 5 N on the uncoated soda-lime glass, but no traces on the coated glass.

Further, the coefficient of friction of the DLC coated substrates obtained from Examples 1 to 4 was compared with the coefficient of friction of uncoated soda-lime glass, the coefficient of friction for Examples 1 to 4 being comparable and significantly lower than that for uncoated soda-lime glass. Lime-glass. Similar results were obtained in coated and uncoated

Borosilicate glass and coated and uncoated stainless steel found.

The coating significantly reduces the coefficient of friction.

Fig. 6 illustrates another embodiment of a coated substrate according to the invention. The substrate ("glass") is a glass substrate. On the glass substrate, an ion diffusion barrier layer ("Si3N4") of S13N4 is applied. Above it is a DLC layer ("DLC"). This is followed by a metallic layer ("Mg + Cu") of an Mg-Cu alloy. Alternatively, z. As a Mg-Al or Mg-Al-Cu alloy conceivable. An oxygen barrier layer ("Si3N4") is on the metallic layer.

LIST OF REFERENCE NUMBERS

1 substrate

2 layer of diamond-like carbon (DLC)

3 metallic, single or multi-layer coating

4 oxygen barrier layer

5 ion diffusion barrier layer (optional)

Claims

claims

1 . Coated substrate, wherein the coating from the substrate (1) comprises in this order:

a. a layer of diamond-like carbon (2),

b. a metallic, single or multilayer coating (3) and

c. an oxygen barrier layer (4),

wherein the metallic, single or multilayer coating (3)

b1) tin or tin and at least one alloying element for tin, which is present unalloyed and / or alloyed, and the proportion of tin in the metallic, single or multilayered layer (3) in the range from 50 atomic% to 1 00 atomic% lies,

or

b2) magnesium and at least one alloying element for magnesium, which are present in unalloyed and / or alloyed, contains and the proportion of magnesium in the metallic, single or multi-layered layer (3) in the range of 50 atom% to 99 atomic%.

2. Coated substrate according to claim 1, wherein the at least one

Alloy element for tin is selected from antimony, copper, lead, silver, I ndium, gallium, germanium or a combination thereof, preferably from copper, silver, I ndium or a combination thereof, and / or

wherein the at least one alloying element for magnesium is selected from aluminum, bismuth, manganese, copper, cadmium, iron, strontium, zirconium, thorium, lithium, nickel, lead, silver, chromium, silicon, tin, gadolinium, yttrium, calcium, antimony or a combination thereof, preferably of aluminum, manganese, copper, silicon or a combination thereof.

The coated substrate of claim 1 or claim 2 wherein the portion of b1) is tin or tin and at least one alloying element for tin or the portion of b2) magnesium and at least one

Alloying element for magnesium in the metallic, single or multi-layered layer (3) in the range of 90 atom% to 1 00 atom%, preferably from 95 atom% to 1 00 atom%.

A coated substrate according to any one of claims 1 to 3, wherein the content of tin in the metallic single-layer or multi-layer (3) is in the range of 60 at% to 1 00 at%, preferably 70 at% 1 00 atomic%, more preferably from 80 atomic% to 1 00 atomic% and in particular from 90 atomic% to 1 00 atomic%, or wherein the proportion of magnesium in the metallic, single or multilayer coating ( 3) is in the range of 50 at% to 99 at%, preferably 60 at% to 95 at%.

A coated substrate according to any one of claims 1 to 4, wherein the metallic single-layer or multi-layer (3) comprises tin, a tin alloy or a magnesium alloy, preferably a magnesium alloy

Aluminum and / or copper, contains or consists of, wherein the

metallic layer (3) is preferably single-layered.

6. Coated substrate according to one of claims 1 to 4, wherein the

metallic, single-layer or multi-layer (3) is formed from two, three or more layers,

wherein one or more layers containing tin and one or more layers containing at least one alloying element for tin, preferably selected from copper, silver and / or I ndium, are arranged alternately, or

wherein one or more layers containing magnesium and one or more layers containing at least one alloying element for

Magnesium, preferably selected from aluminum and / or copper, are arranged alternately.

7. Coated substrate according to one of the preceding claims, wherein the proportion of tin or of magnesium in the oxygen barrier layer (4) in each case <1 0 atomic%, preferably <5 atomic% and in particular <2 atomic%.

8. Coated substrate according to one of the preceding claims, wherein the

Oxygen Barrier Layer (4) contains or consists of silicon carbide, silicon nitride, silicon oxynitride, metal nitride, metal carbide or a combination thereof, with S 13N4 and / or doped S 13N4 being preferred and Z 13N4 doped with Zr, Ti, Hf and / or B being particularly preferred.

9. Coated substrate according to one of the preceding claims, wherein the oxygen barrier layer (4) has a layer thickness of 10 to 1 00 nm, preferably from 20 to 80 nm.

1 0. Coated substrate according to one of the preceding claims, wherein the coating further comprises between the substrate (1) and the layer of diamond-like carbon (2) one or more ion diffusion barrier layers (5), which preferably silicon carbide, silicon oxide,

Silicon nitride, silicon oxynitride, metal oxide, metal nitride, metal carbide or a combination thereof, wherein S 13N4 and / or doped S 13N4 is preferred and Zr, Ti, Hf and / or B doped S 13N4 is particularly preferred.

1 1. Coated substrate according to one of the preceding claims, wherein the layer of diamond-like carbon (2) has a layer thickness of 1 nm to 20 nm, preferably 2 nm to 10 nm, particularly preferably 3 nm to 8 nm, and / or the metallic, single-layer or multi-layer (3) has a layer thickness of 1 nm to 50 nm, preferably from 2 nm to 40 nm, particularly preferably from 5 nm to 25 nm.

12. Coated substrate according to one of the preceding claims, wherein the substrate (1) is ceramic, glass ceramic or glass, glass being preferred.

1 3. Coated substrate according to one of the preceding claims, wherein the metallic, single or multilayer film (3) contains tin or a

Tin layer is, the oxygen barrier layer (4) S 13N4 and / or doped S 13N4, in particular Zr doped S 13N4, contains or consists thereof, and optionally between the substrate (1) and the layer of

diamond-like carbon (2) at least one

Ion diffusion barrier layer (5) is arranged, the S 13N4 and / or doped S 13N4, in particular Zr doped S 13N4, contains or consists thereof.

14. Coated substrate according to one of the preceding claims, wherein the metallic, single or multilayer film (3) is formed by sputtering, preferably magnetron sputtering or co-sputtering, or by CVD, preferably PECVD, or by ion beam evaporation.

A coated substrate according to any one of the preceding claims wherein the layer of diamond-like carbon (2) is undoped or doped. 6. A process for producing a heat-treated substrate with a

A coating comprising a layer of diamond-like carbon (2), comprising:

a. Heat treatment of a coated substrate according to one of

Claims 1 to 14, preferably at a temperature of 300 to 800 ° C, and

b. Removing the oxygen barrier layer (4) and the metallic, single or multilayered layer (3) from the heat treated coated substrate by a washing process.