EP2737101A2 - Coating method using special powdered coating materials and use of such coating materials - Google Patents

Abstract

The invention relates to the use of a particle-containing powdered coating material in a coating method selected from the group consisting of cold gas spraying, flame spraying, high speed flame spraying, thermal plasma spraying and non-thermal plasma spraying, the particles having a relative deformability factor V _m of a maximum of 0.1 and the relative deformability factor being defined as per formula (1), d being the average lowest thickness of the particles measured vertically to and in the middle half of the longitudinal axis of the particles, and D ₅₀ being the mean diameter of the volume-averaged particle size distribution. The invention further relates to a coating method.

Description

 Coating method using special powdery

 Coating materials and use of such

 coating materials

The present invention deals with specific powdered

Coating materials. Furthermore, the present invention comprises the

Use of such powdered coating materials. Further, the present invention includes methods of substrate coating using such powdery coating materials.

There are already a variety of coating methods for different substrates known. For example, metals or their precursors are deposited from the gas phase on a substrate surface, see e.g. PVD or CVD method. Furthermore, corresponding substances can be deposited, for example, from a solution by means of galvanic methods. It is also possible to apply coatings, for example in the form of paints, to the surface. However, all methods have specific advantages and disadvantages.

For example, in the application in the form of paints, large amounts of water and / or organic solvents are required, a drying time is required, the coating material to be applied must be compatible with the basecoat and a remainder of the basecoat also remains on the Substrate. For example, PVD deposition requires large amounts of energy to vaporize low volatility material.

In view of the above limitations has been a variety of

Coating process developed to provide the desired properties for the particular application. Known methods use for generating the coatings, for example, kinetic energy, thermal energy or mixtures thereof, wherein the thermal energy may for example come from a conventional combustion flame or a plasma flame. The latter are further distinguished in thermal and non-thermal plasmas, which have in common that a gas is partially or completely separated into free charge carriers such as ions or electrons.

In cold gas spraying, the formation of the coating takes place by applying a powder to a substrate surface, the powder particles being greatly accelerated. For this purpose, a heated process gas is accelerated by expansion in a Laval nozzle to supersonic speed and then injected the powder. Due to the high kinetic energy, the particles form a dense layer upon impact with the substrate surface.

For example, WO 2010/003396 A1 discloses the use of the

Cold gas spraying as a coating method for applying

Wear protection coatings. Furthermore, disclosures of the cold gas spraying process can be found, for example, in EP 1 363 81 1 A1, EP 0 91 1 425 B1 and US Pat. No. 7,740,905 B2.

Flame spraying belongs to the group of thermal coating processes. Here, a powdery coating material is introduced into the flame of a fuel gas-oxygen mixture. In this case, for example, can be achieved with acetylene oxygen flames temperatures of up to about 3200 ° C. become. Details about the method can be found in publications such as EP 830 464 B1 and US Pat. No. 5,207,382.

In thermal plasma spraying, a powdered coating material is injected into a thermal plasma. In the typically used thermal plasma, temperatures of up to about 20,000 K are reached, causing the injected powder to melt and as a coating on a substrate

is deposited. The process of thermal plasma spraying and specific

 Embodiments and process parameters are known to the person skilled in the art. By way of example, reference is made to WO 2004/016821, which describes the use of thermal plasma spraying for applying an amorphous coating. Further, for example, EP 0 344 781 discloses the use of flame spraying and thermal plasma spraying as

 Coating method using a tungsten carbide powder mixture. Specific devices for use in plasma spraying methods are widely described in the literature, such as in EP 0 342 428 A2, US 7,678,428 B2, US 7,928,338 B2 and EP 1 287 898 A2.

In high velocity flame spraying, fuel is burned under high pressure, and as fuel, fuel gases, liquid fuels and mixtures thereof can be used. In the high-accelerated flame, a powdery coating material is injected. This method is known to be characterized by relatively dense spray coatings. Also the high speed flame spraying is the

Expert well known and has been described in numerous publications. For example, EP 0 825 272 A2 discloses a

Substrate coating with a copper alloy using the

Hochgeschwindigkeitsflammspritzens. Further, for example, disclose WO 2010/037548 A1 and EP 0 492 384 A1, the method of

High speed flame spraying and apparatus for use herein.

The non-thermal plasma spraying is largely analogous to thermal plasma spraying and flame spraying. A powdered coating material is injected into a non-thermal plasma and thereby onto a

Substrate surface applied. As can be seen, for example, from EP 1 675 971 B1, this method is distinguished by a particularly low thermal load of the coated substrate. Also this method, special embodiments and corresponding

 Process parameters are known to those skilled in the art from various publications. For example, EP 2 104 750 A2 describes the use of this method and an apparatus for carrying it out. For example

DE 103 20 379 A1 describes the production of an electrically heatable element using this method. Further disclosures regarding the method or devices for non-thermal plasma spraying can be found, for example, in EP 1 675 971 B1, DE 10 2006 061 435 A1, WO 03/064061 A1, WO 2005/031026 A1, DE 198 07 086 A1, DE 101 16 502 A1, WO 01/32949 A1, EP 0 254 424 B1, EP 1 024 222 A2, DE 195 32 412 A1, DE 199 55 880 A1 and DE 198 56 307 C1.

However, a general problem of coating methods using a powdery coating material is that under relatively mild coating conditions, only an insufficient coating quality is achieved. In particular, incomplete melting of the particles of the pulverulent coating material form cavities which may influence, for example, the optical, haptic or electrical properties, the barrier effect and / or the thermal conductivity of the coating. An object of the present invention is to provide a device for use in

Coating process to provide suitable powdered Beschichtungsmatehal, wherein the preparation of known coatings improved or the production of new coatings are made possible.

Another object of the present invention is a method

to provide the production of a high-quality and homogeneous coating under the mildest possible coating conditions (temperature, velocity of the impinging particles).

Another object of the present invention is to provide a powdered coating material that offers advantages over the known powdered coating materials when used in the coating of substrates.

The present invention relates to the use of a particle-containing powdery coating material in a coating process selected from the group consisting of cold gas spraying, flame spraying, high-speed flame spraying, thermal plasma spraying and

non-thermal plasma spraying, the particles having a relative

Deformability factor V _m of at most 0.1 and the relative

Deformability factor according to formula (I) is defined:

Here, V _m denotes the relative deformability factor. Further, d denotes the average smallest thickness of the particles, measured vertically to and in the middle half of the longitudinal axis of the particles. To determine this thickness, at least 50 randomly selected particles are measured and from this the mean value is formed. The term D ₅₀ is the average particle size at 50% of the volume-average particle size distribution below said size lie. The determination of the D ₅₀ is preferably carried out by means of laser granulometry, wherein, for example, a particle size analyzer type HELOS the Fa.

Sympatec GmbH, Clausthal-Zellerfeld, Germany. The

Dispersion of a dry powder can be carried out here with a dispersion unit of the Rodos T4.1 type at a primary pressure of, for example, 4 bar. Alternatively, size distribution curve of the particles can be measured, for example, with a device from the company Quantachrome (device: Cilas 1064) according to the manufacturer's instructions. For this purpose, 1, 5 g of powdered

Coating material suspended in about 100 ml of isopropanol, 300 seconds in an ultrasonic bath (device: Sonorex IK 52, Fa. Bandelin) treated and then added using a Pasteur pipette in the sample preparation cell of the meter and measured several times. From the individual measurement results, the resulting averages are formed. The evaluation of the scattered light signals is carried out according to the Fraunhofer method.

In certain embodiments of the above-mentioned use, the relative deformability factor is defined taking into account the Mohs hardness of silver-related Mohs hardness of the particles according to formula (II):

where H is the Mohs hardness of the particles and H _{Ag is} the Mohs hardness of silver. For substances X with a Mohs hardness (H _x ) less than the Mohs hardness of silver (H _Ag ), the Mohs hardness of the silver shall be used.

In certain embodiments of the aforementioned uses, the relative ductility factor of the powdered coating material is at most 0.01. In certain embodiments of the aforementioned uses, the technical elastic limit of the particles of the powdered

Coating material more than 45 N / mm ² . In certain embodiments of the above-mentioned uses, the melting point of the coating material measured in [K] is up to 60% of the temperature of the substrate-oriented medium used in the coating process, for example, the gas flow, measured in [K]

Combustion flame or plasma flame.

In certain embodiments of the aforementioned uses, the particles of powdered coating material include or are metal particles, the metal being selected from the group consisting of silver, gold, platinum, palladium, vanadium, chromium, manganese, cobalt, germanium, antimony, aluminum, zinc, Tin, iron, copper, nickel, titanium, silicon, alloys and mixtures thereof.

In certain embodiments of the aforementioned uses, the coating process is selected from the group consisting of

Flame spraying, and non-thermal plasma spraying. Preferably, in certain of the foregoing embodiments, the coating process is nonthermal plasma spraying.

In certain embodiments of the aforementioned uses, the powdery coating material has a particle size distribution with a D ₅₀ value in the range from 1.5 to 84 μm.

In certain embodiments of the aforementioned uses, the powdery coating material has a particle size distribution with a Di ₀ - Value from a range of 3.7 to 26 μητι, a D ₅₀ value from a range of 6 to 49 μΐη and a D ₉₀ value from a range of 12 to 86 μηη on.

In certain embodiments of the aforementioned uses, the span of the powdered coating material is at most 2.9, the chip being defined according to formula (III):

In certain embodiments of the aforementioned uses, the particles of the powdery coating material are at least partially coated. In certain of the aforementioned embodiments, the particles of the powdery coating material are coated.

Furthermore, the present invention relates to a method for coating a substrate selected from the group consisting of cold gas spraying,

Flame spraying, high-speed flame spraying, thermal

Plasma spraying and non-thermal plasma spraying, the method comprising the step of introducing a particle-containing powdered coating material into a medium directed onto the substrate, the particles having a relative ductility factor V _m of at most 0.1 and the relative ductility factor according to formula ( I) is defined:

where c / is the average minimum thickness of the particles, measured vertically to and in the middle half of the longitudinal axis of the particles, and D _{50 is} the mean diameter of the volume-average particle size distribution.

In certain embodiments of the aforementioned method, the method is selected from the group consisting of flame spraying and non-medical plasma spraying. Preferably, in certain of the foregoing embodiments, the coating process is nonthermal plasma spraying. In certain embodiments of the aforementioned methods, the powdery coating material is conveyed as an aerosol.

In certain embodiments of the aforementioned methods, the medium directed to the substrate is air or was generated from air. The aforementioned air can be taken from the ambient atmosphere. In certain embodiments where, for example, a particularly high purity of the coating is desired, the air is cleaned prior to its use, wherein, for example, dust and / or water vapor is separated. It may also be preferred that the gaseous constituents of the air are substantially completely separated apart from nitrogen and oxygen (total amount <0.01% by volume, preferably <0.001% by volume).

The term "powdery coating material" in the context of the present invention refers to a particle mixture which acts on the substrate as

Coating is applied. It is not necessary in this case for the particles of the powdery coating material according to the invention to have a uniform thickness. Without it being to be understood as limiting the invention, it is the view of the inventors that the

particles of the powdery coating material according to the invention can be particularly easily mechanically deformed and thereby significantly simpler unevenness of the substrate and gaps in the already applied

Fill coating without the need to melt the particles by means of a large amount of thermal energy or very strong to accelerate sufficient kinetic energy for deformation

provide. For example, this is not only observed with uniformity thin particles, but also with particles of irregular thickness, since the thinnest points are here in the view of the inventors as weak points particularly easily deformed and by deformation of the particles of such

Weak points a particularly easy adaptation to the ground is made possible.

To the surprise of the inventors, it has been found that significantly more homogeneous coatings with reduced number and size or even without cavities can be obtained even under very mild conditions by using the powdery coating material according to the invention. This is achieved by the production and use of powdered

Coating materials which have a particularly high relative deformability. This high relative deformability is caused by in

Ratio to the average size of the total particles very thin spots or areas. Without intending to be construed as limiting the invention, it is the view of the inventors that such thin spots or regions

Have weak points where deformation of the particles can take place particularly easily. This results in a particularly good adaptation to, for example, the surface structure of the substrate already under very mild conditions.

In addition, it has surprisingly been observed that the powdered coating material according to the invention sprays to a reduced extent from the surface of the substrate during the application of the coating. Without intending to be construed as limiting the invention, it is the view of the inventors that the higher mechanical deformability of the particles of the invention results in a lighter conversion of the kinetic energy into a deformation of the particle, whereby the tendency for an elastic shock

as a result of the particles being sprayed off from the substrate to be coated, this being particularly advantageous in use, for example expensive or poorly recyclable coating materials. This effect is of particular importance for processes using high

Gas velocities, in particular, for example, the cold gas spraying and high-speed flame spraying.

The particles of the powdery coating material according to the invention are therefore characterized by the abovementioned upper limit of the relative

Deformability factor. The relative deformability factor is defined according to formula I.

Here, V _m denotes the relative deformability factor. Further, d denotes the average smallest thickness of the particles, measured vertically to and in the middle half of the longitudinal axis of the particles. To determine this

average thickness, at least 50 randomly selected particles are measured by means of SEM and from this the mean value is formed. The term D ₅₀ denotes the mean particle size in the 50% of the volume-averaged

Particle size distribution below the size mentioned. The determination of the D ₅₀ is preferably carried out by means of laser granulometry, using, for example, a HELOS particle size analyzer from Sympatec GmbH, Clausthal-Zellerfeld, Germany.

However, the mechanical deformability of the particles depends to a certain extent on the hardness of the material used. For certain

Embodiments may therefore be preferred to introduce a correction factor based on the Mohs hardness of the material, as long as the Mohs hardness is above that of the silver. For substances with a Mohs hardness below that of silver, however, such a correction is only minor, which is why such substances the Mohs hardness of silver is used. The corrected relative

The adaptability factor results from formula II

Here, H _{Ag is} the Mohs hardness of silver (2.7) and H _{x is} the Mohs hardness of the material of the particles of the powdery coating material.

In cases where the particles of the powdered Beschichtungsmatenals were provided with a coating whose Mohs hardness above that of

the Mohs hardness of the powdery coating material is calculated by summing the Mohs hardness of the materials of the layers corrected by the relative proportion of the respective layer to the total thickness according to formula IV:

Ηχ- Γι * Ηι + Γ2 * Η2 ⁺ (IV)

Here, r _x denotes the average proportion of the thickness of the layer X on the total particle. The average thickness of the layer is preferably determined by means of SEM by measuring 50 randomly selected particles.

In particular, it is preferred in certain embodiments that the relative deformability factor according to formula (I) or (II), if appropriate taking into account formula (IV), of the pulverulent according to the invention

Coating material has a relative deformability factor of at most 0.1, preferably of at most 0.07, more preferably of at most 0.05 and even more preferably at most 0.03. In particular, it is preferred in certain of the aforementioned embodiments that the relative

Deformability factor of the powdery coating material at most 0.01, preferably at most 0.007, more preferably at most 0.005 and even more preferably at most 0.003.

Processes according to the invention which can be used to build up coatings are cold gas spraying, thermal plasma spraying,

non-thermal plasma spraying, flame spraying and

 High velocity flame spraying. The use of the powdery coating materials according to the invention has a particularly pronounced effect in processes in which no particularly high kinetic energies are transferred to the particles, since sufficient deformation of the particles is already achieved at significantly lower speeds. For certain

Embodiments therefore prefer that the method be selected from the group consisting of thermal plasma spraying, non-thermal plasma spraying and flame spraying.

Many powdered coating materials are completely melted in the thermal plasma in the thermal plasma spraying, so that only a liquid impinges on the surface of the substrate and the additional expense associated with the provision of the inventive

powdery coating materials, is uneconomical. In certain embodiments, therefore, the method is selected from the group consisting of cold gas spraying, non-thermal plasma spraying, flame spraying and high velocity flame spraying, preferably from the group consisting of non-thermal plasma spraying and flame spraying.

The use of a plasma offers the advantage that non-combustible gases can also be used as the plasma gas, thereby simplifying the apparatus and, in particular, the necessary safety precautions. Thus, for most cases a harmless, easy-to-use gas is used and for special process variants small amounts of other gases to be stored in stock. In certain embodiments, it is therefore preferred that the method be selected from the group consisting of thermal plasma spraying and non-thermal plasma spraying. In particular, it is preferred in certain of the aforementioned embodiments that non-thermal plasma spraying is used as the coating method.

Furthermore, it was surprisingly found that by means of

According to the invention powdery Beschichtungsmatenalien also very homogeneous coatings under gentle coating conditions can be made of substances that have a high yield strength. The yield strength is a relative limit that reflects a relation between the stress applied to a material and the resulting plastic deformation. Of particular importance in this case is the 0.2% proof stress, which is also referred to as the technical elastic limit. In certain embodiments, it is preferred that the technical elastic limit of the used

Coating material is more than 45 N / mm ² , preferably more than 70 N / mm ² , more preferably more than 85 N / mm ² and even more preferably more than 100 N / mm ² . In particular, it is with certain of the aforementioned

Embodiments preferred that the technical elastic limit of the coating material of the invention is more than 130 N / mm ² , preferably more than 160 N / mm ² , more preferably more than 190 N / mm ² and even more preferably more than 210 N / mm ² . The determination of the technical

Without being to be understood as a limitation of the invention, it is the view of the inventors that previously used pulverformige Beschichtungsmatenalien when using gentle coating conditions when hitting the surface were not sufficiently deformed, therefore, the

Surface structure or structure of the already applied coating could not sufficiently adapt and include cavities. Both

However, it is not according to the invention powdered Beschichtungsmatenalien more necessary that the entire particle is deformed, but only the thin points or areas according to the invention must be deformed to allow an adaptation to the existing surface structure. Therefore, significantly lower forces are required for the deformation of fabrics with high technical elastic limit and significantly milder coating conditions can be used for the coating of the invention.

In addition, it has surprisingly been found that even easily accessible particles having a significantly uneven thickness can be used according to the invention. Without it being to be understood as a limitation of the invention, it is the view of the inventors that the aforementioned locations of the smallest thickness of the particles significantly affect the ductility and also significantly thicker existing locations or areas the adaptation of the particles to, for example, the surface of the substrate not in seriously disturb. It may therefore be preferable to use such non-uniform particles, for example to save the additional expense of providing particularly uniformly shaped particles. In certain embodiments, it is therefore preferred that the average ratio of the largest thickness to the smallest thickness, measured vertically to and in the middle half of the longitudinal axis of the particles, be at least 1.3, preferably at least 1.4, more preferably at least 1.5, and even more preferably at least 1.6. In particular, in certain embodiments it is preferred that the average ratio of the thickest point to the thinnest point measured vertically to and in the middle half of the longitudinal axis of the particles is at least 1.8, preferably at least 2.0, more preferably at least 2.2 and even more preferably at least 2.4. The determination of the average greatest thickness is analogous to the determination of the aforementioned average minimum thickness. The average ratio of the largest thickness to the smallest thickness is calculated by the average of the ratio of at least 50 randomly selected particles. Furthermore, the inventors have surprisingly found that by the

Use of the mechanically easily deformable according to the invention

powdered Beschichtungsmatehalien also the use of

Coating materials with an unexpectedly high melting point is made possible. Without it being to be understood as a limitation of the invention, it is the view of the inventors that the particles of the powdery coating material selected according to the invention have already been replaced by those in the present invention

Coating used kinetic energy at least one

largely sufficient energy is available to adapt the particles to the substrate surface or the gaps between already applied particles. If a thermal component is required at all, a significantly reduced amount of thermal energy is needed to allow a solid connection of the deposited particles to form a homogeneous layer.

For example, in certain embodiments powdery coating materials according to the invention may also be used to produce homogeneous

Layers are used when the melting point of the particles of the coating material measured in [K] is up to 60%, preferably up to 70%, more preferably up to 80% and even more preferably up to 85% of that in [K]

measured temperature of the medium used in the coating process, for example gas flow, the combustion flame and / or the plasma flame is. In certain of the aforementioned embodiments may further be used according to the invention particle-containing powdery

Coating materials can also be used to produce homogeneous layers if the melting point of the particle measured in [K] is

Coating material up to 90%, preferably up to 95%, more preferably up to 100% and even more preferably up to 105% of the temperature measured in [K] of the medium used in the coating process,

For example, gas flow, the combustion flame and / or the plasma flame is. The abovementioned percentages relate to the ratio of the melting temperature of the coating material to the temperature of the gas stream during cold gas spraying, the combustion flame during flame spraying and

High velocity flame spraying or the plasma flame at

non-thermal or thermal plasma spraying in [K]. This is especially true when using the cold gas spraying and the

 Hochgeschwindigkeitsflammspritzens. The resulting coating has only a few free, preferably no, particle or grain structures. The

"Homogeneous layers" according to the invention are characterized in that the layers produced are less than 10%, preferably less than 5%, more preferably less than 3%, even more preferably less than 1% and most preferably less than 0.1% cavities exhibit. In particular it is

preferred that no cavities are visible. The aforementioned term "cavity" in the sense of the present invention describes the proportion of the gaps enclosed in the coating on the two-dimensional surface of a transverse section of the coated substrate, based on that in FIG

two-dimensional surface contained coating. A determination of this proportion is carried out by means of SEM at 30 randomly selected locations of the coating, wherein, for example, a length of 100 μm of the substrate coating is considered.

In addition, it has surprisingly been found that the coatings of the invention have a significantly improved thermal conductivity. Without intending to be construed as limiting the invention, it is the view of the inventors that the coatings produced according to the invention have a thermal conductivity which is close to the thermal conductivity of a homogeneous block of the corresponding coating material due, for example, to their significantly higher homogeneity. This is attributed, inter alia, to the fact that no inclusions of air are contained, the one

Could hinder heat conduction. Surprisingly, it has also been shown that the barrier effect of the coatings according to the invention is drastically increased. Without intending to be construed as limiting the invention, it is the view of the inventors that the coatings produced according to the invention have a denser structure, a smoother surface and a more uniform shape. Since isolated gaps in the coating represent targets for, for example, corrosion of the substrate, the coatings with denser structure and uniform shape produced according to the invention provide more reliable protection even with thin coatings, while the smoother surface offers fewer points of attack where, for example, by mechanical effects Damage to the coating occurs. Furthermore, defined and reliable permeabilities of the coatings can be realized by the coatings produced according to the invention, since for the aforementioned reasons, for example, no indefinitely permeable gaps are present, the uniform formation of the coating provides a uniform barrier effect over the length of the coated substrate and mechanical effects not easy cause damage to the coating.

The determination of the size distribution of the particles is preferably carried out by means of laser granulometry. In this method, the particles can be measured in the form of a powder. The scattering of the irradiated laser light is in

recorded different spatial directions and according to the Fraunhofer

Diffraction theory evaluated. The particles are treated mathematically as spheres. Thus, the determined diameters always relate to the equivalent spherical diameter determined over all spatial directions, irrespective of the actual shape of the particles. It determines the size distribution, which is calculated in the form of a volume average, based on the equivalent spherical diameter. This volume-averaged size distribution can be considered Cumulative frequency distribution. The

Sum frequency distribution is simplified characterized by various characteristics, such as the D10, D ₅ o or D ₉₀ value. The measurements can be carried out, for example, using the particle size analyzer HELOS from Sympatec GmbH, Clausthal-Zellerfeld, Germany.

In certain embodiments of the invention, it is preferred that the powdery coating material has a particle size distribution having a D ₅₀ value of not more than 84 μm, preferably not more than 79 μm, more preferably not more than 75 μm and even more preferably not more than 71 μm.

In particular, it is preferred in certain of the aforementioned embodiments that the powdery coating material is a

Grain size distribution with a D ₅₀ value of at most 64 μητι, preferably at most 61 μητι, more preferably at most 59 μηη and even more preferably at most 57 μηη.

The term "D ₅₀ " in the context of the present invention denotes the

Particle size at which 50% of the above-mentioned particle size distribution by means of laser granulometry is below the stated value. The measurements may, for example, according to the aforementioned

Measuring method with a particle size analyzer HELOS Fa. Sympatec GmbH, Clausthal-Zellerfeld, Germany, performed. In certain embodiments of the invention it is further preferred that the powdery coating material has a particle size distribution with a D ₅₀ value of at least 1.5 μητι, preferably at least 2 μητι, more preferably at least 4 μηη and even more preferably at least 6 μηη,

In particular, it is preferred in certain of the aforementioned embodiments that the powdery coating material is a Particle size distribution with a D ₅₀ value of at least 7 μητι, preferably at least 9 μητι, more preferably at least 1 1 μηη and more preferably at least 13 μηη In certain embodiments, it is particularly preferred that the powder has a particle size distribution with a D ₅₀ value from a range of 1, 5 to 84 μητι, preferably from a range of 2 to 79 μητι, more preferably from a range of 4 to 75 μηη and even more preferably from a range of 6 to 71 μΐη. In particular, it is preferred in certain of the aforementioned embodiments, that the powder has a particle size distribution with a D ₅₀ value from a range of 7 to 64 μητι, preferably from a range of 9 to 61 μητι, more preferably from a range of 1 1 to 59 μηη and more preferably from a range of 13 to 57 μηη. In other embodiments, it is preferred, for example, that the powder has a particle size distribution with a D ₅₀ value from a range of 1.5 to 53 μm, preferably from a range from 2 to 51 μm, more preferably from a range of 2.5 to 50 μηη, and more preferably from a range of 3 to 49 μΐη. In particular, it is with certain of the aforementioned

Embodiments preferred that the powder has a particle size distribution with a D ₅₀ value from a range of 3.5 to 48 μητι, preferably from a range of 4 to 47 μητι, more preferably from a range of 4.5 to 46 μηη and even more preferably from a range of 5 to 45 μηη. In yet other embodiments, it is preferred, for example, that the powder has a particle size distribution with a D ₅₀ value from a range of 9 to 84 μητι, preferably from a range of 12 to 79 μητι, more preferably from a range of 15 to 75 μητι , more preferably from a range of 17 to 71 μηη. In particular it is with certain of the aforementioned embodiments preferred that the powder has a particle size distribution with a D ₅₀ value from a range of 19 to 64 μητι, preferably from a range of 21 to 61 μητι, more preferably from a range of 23 to 59 μηη and even more preferably from a Range of 25 to 57 μΐη has.

In further specific embodiments of the invention, it is preferred that the powdery coating material has a particle size distribution with a Dgo value of at most 132 μητι, preferably at most 122 μητι, more preferably at most 1 15 μηη and even more preferably at most 109 μηη.

In particular, it is preferred in certain of the aforementioned embodiments, that the powdery coating material has a D ₉₀ value of at most 97 μητι, preferably at most 95 μητι, more preferably at most 91 μΐη and even more preferably at most 89 μηη.

The term "D ₉₀ " in the context of the present invention denotes the

Particle size at which 90% of the above-mentioned particle size distribution by means of laser granulometry is below the stated value. The measurements may, for example, according to the aforementioned

Measuring method with a particle size analyzer HELOS Fa. Sympatec GmbH, Clausthal-Zellerfeld, Germany, performed.

In certain embodiments, it is therefore preferred that the

powdery coating material having a particle size distribution with a D ₉₀ - value of at least 9 μητι, preferably at least 1 1 μητι, more preferably at least 13 μηη and even more preferably at least 15 μηη.

In particular, it is preferred in certain of the aforementioned embodiments that the powdery coating material is a

Grain size distribution with a D ₉₀ value of at least 17 μητι, preferably at least 19 μητι, more preferably at least 21 μηη and even more preferably at least 22 μηη.

According to certain preferred embodiments, the powdery coating materials have a particle size distribution with a D ₉₀ value from a range of 42 to 132 μιτι, preferably from a range of 45 to 122 μιτι, more preferably from a range of 48 to 1 15 μηη and even more preferably from a range of 50 to 109 μηη. In particular, it is preferred in certain of the aforementioned embodiments that the

powdery coating material a D ₉₀ value from a range of 52 to 97 μιτι, preferably from a range of 54 to 95 μιτι, more preferably from a range of 56 to 91 μηη and even more preferably from a range of 57 to 89 μηη. In further specific embodiments of the invention, it is preferred that the powdery coating material has a particle size distribution with a Dio value of at most 9 μητι, preferably at most 8 μητι, more preferably at most 7.5 μηη and even more preferably at most 7 μηη.

In particular, it is preferred in certain of the aforementioned embodiments that the powdery coating material is a

Grain size distribution with a Di ₀ value of at most 6.5 μητι, preferably at most 6 μητι, more preferably at most 5.7 μηη and even more preferably at most 5.4 μηη. The term "Di ₀ " in the context of the present invention denotes the

 Particle size at which 10% of the above-mentioned particle size distribution by means of laser granulometry is below the stated value. The measurements may, for example, according to the aforementioned

Measuring method with a particle size analyzer HELOS Fa. Sympatec GmbH, Clausthal-Zellerfeld, Germany, performed. On the other hand, the high-fines powdery coating materials also greatly tend to form fine dusts, causing the

Handling appropriate powder is significantly more difficult. In certain embodiments, it is therefore preferred that the powdered

Coating material a particle size distribution with a Di ₀ value of at least 0.2 μητι, preferably at least 0.4 μητι, more preferably

have at least 0.5 μηη and even more preferably at least 0.6 μηη.

In particular, it is preferred in certain of the aforementioned embodiments that the powdery coating material is a

Grain size distribution with a Di ₀ value of at least 0.7 μητι, preferably 0.8 μητι, more preferably 0.9 μηη and even more preferably at least 1, 0 μηη. In certain preferred embodiments, this is powdery

Coating material characterized in that it has a

Grain size distribution with a Di ₀ value from a range of 0.2 to 9 μητι, preferably from a range of 0.4 to 8 μητι, more preferably from a range of 0.5 to 7.5 μηη and even more preferably from a Range from 0.6 to 7 μΐη have. In particular, it is with certain of the aforementioned

Embodiments preferred that the powdery coating material a particle size distribution with a Di ₀ value from a range of 0.7 to 6.5 μητι, preferably from a range of 0.8 to 6 μητι, more preferably from a range of 0.9 to 5.7 μηη, and more preferably from a range of 1, 0 to 5.4 μηη

In particular, it is preferred, for example, in certain embodiments, that the powdery coating material μιτι a particle size distribution having a Di ₀ value of 3.7 to 26 μιτι, a D ₅₀ value of 6 to 49 μιτι and a Dgo value of 12 to 86 μιτι , For certain of the above Embodiments, it is particularly preferred that the powdered

Beschichtungsmatehal a grain size distribution with a Di ₀ value of 5.8 to 26 μιτι, a D ₅₀ value of 1 1 to 46 μιτι and a D ₉₀ value of 16 to 83 μιτι. In certain of the aforementioned embodiments, it is even more preferable that the powdery coating material has a

Particle size distribution with a Di ₀ value of 9 to 19 μιτι, a D ₅₀ value of 16 to 35 μιτι and a D ₉₀ value of 23 to 72 μιτι.

In further specific embodiments, it is preferred, for example, for the pulverulent coating material to have a particle size distribution with a Di ₀ value of 0.8 to 60 μm, a D ₅₀ value of 1.5 to 84 μm and a Dco value of 2.5 has up to 132 μιτι. For certain of the above

Embodiments, it is particularly preferred that the powdered

Coating material has a particle size distribution with a Di ₀ value of 2.2 to 56 μιτι, a D ₅₀ value of 4 to 79 μιτι and a D ₉₀ value of 4 to 122 μιτι. In certain of the aforementioned embodiments, it is even more preferable that the powdery coating material has a

Particle size distribution with a Di ₀ value of 2.8 to 49 μιτι, a D ₅₀ value of 6 to 71 μιτι and a D ₉₀ value of 9 to 109 μιτι.

In further specific embodiments, it is preferred, for example, for the pulverulent coating material to have a particle size distribution with a Di ₀ value of 4.8 to 44 μm, a D ₅₀ value of 9 to 64 μm and a Dco value of 13 to 97 μm , For certain of the above

Embodiments, it is particularly preferred that the powdered

Coating material has a particle size distribution with a Di ₀ value of 12 to 41 μιτι, a D ₅₀ value of 23 to 59 μιτι and a D ₉₀ value of 35 to 91 μιτι. In certain of the aforementioned embodiments, it is even more preferable that the powdery coating material has a Particle size distribution with a Di ₀ value of 15 to 39 μιτι, a D ₅₀ value of 28 to 57 μιτι and a D ₉₀ value of 41 to 89 μιτι.

It was also observed that the solubility of the powdered

Beschichtungsmatenals depends on the width of the particle size distribution. A calculation of this width can be made by specifying the so-called Span value, which is defined according to formula (III):

D ₉₀ - D

 Span 10

 '50

The inventors have found that the use of a lower span powdered coating material in certain embodiments achieves, for example, even more uniform recoverability of the powdered coating material, thereby further simplifying the formation of a more homogeneous and higher quality layer. For certain

 Therefore, it is preferred that the span of the powdery coating material is at most 2.9, preferably at most 2.6, more preferably at most 2.4, and even more preferably at most 2.1.

In particular, in certain of the aforementioned embodiments it is preferred that the span of the powdered coating material is at most 1, 9, preferably at most 1, 8, more preferably at most 1, 7 and even more preferably at most 1, 6.

On the other hand, the inventors have found that a very narrow chip is not necessarily required to provide the required level of demand, which facilitates the production of the powdered coating material. at

In certain embodiments, it is therefore preferred that the span of the powdered coating material is at least 0.4, preferably at least 0.5, more preferably at least 0.6, and even more preferably at least 0.7. In particular, it is preferred in certain embodiments that the span value of the powdered coating material is at least 0.8, preferably at least 0.9, more preferably at least 1.0, and even more preferably at least 1.1.

Based on the teachings disclosed herein, one skilled in the art may choose any combination, in particular, of the aforementioned span value limits to provide the desired combination of properties. For example, in certain embodiments, it is preferred that the powdered coating material have a span value in the range of 0.4 to 2.9, preferably in the range of 0.5 to 2.6, more preferably in the range of 0.6 to 2.4, and more preferably from a range of 0.7 to 2.1. In particular, it is with certain of the aforementioned

Embodiments preferred that the powdery coating material has a span value from a range of 0.8 to 1, 9, preferably from a range of 0.9 to 1, 8, more preferably from a range of 1, 0 to 1, 7 and even more preferably from a range of 1.1 to 1.6.

The skilled worker is aware that based on the teachings disclosed herein, depending on the desired combination of the advantages of certain combinations of the chip limits or ranges of values with the aforementioned preferred D ₅₀ - value ranges are preferred. For example, the powdery

Coating material in certain preferred embodiments, a particle size distribution with a span from a range of 0.4 to 2.9 and a D ₅₀ value from a range of 1, 5 to 53 μητι, preferably from a range of 2 to 51 μητι, more preferably from a range of 4 to 50 μητι, more preferably from a range of 6 to 49 μηη and most preferably from a range of 7 to 48 μηη on. In certain preferred of the aforementioned embodiments, the powdery

Coating material a particle size distribution with a chip of one Range of 0.5 to 2.6 and a D ₅₀ value from a range of 1, 5 to 53 μητι, preferably from a range of 2 to 51 μητι, more preferably from a range of 4 to 50 μητι, even more preferably from a range of 6 to 49 μΐη, and most preferably from a range of 7 to 48 μηη. In certain further preferred embodiments, the powdered coating material has a particle size distribution with a span of from 0.6 to 2.4 and a D ₅₀ value from a range of 1.5 to 53 μm, preferably from a range of 2 to 51 μητι, more preferably from a range of 4 to 50 μητι, even more preferably from a range of 6 to 49 μΐη and most preferably from a range of 7 to 48 μηη on. In certain even more preferred embodiments, the powdered coating material has a particle size distribution with a span of from 0.7 to 2.1 and a D ₅₀ value of from 1.5 to 53 μm, preferably from a range of 2 to 51 μητι, more preferably from a range of 4 to 50 μητι, even more preferably from a range of 6 to 49 μΐη and most preferably from a range of 7 to 48 μηη on.

Furthermore, it was found that the density of the powdery

Beschichtungsmatenals may have an impact on the promotion of such powders in the form of an aerosol. Without it being to be understood as limiting the invention, it is the view of the inventors that the

Inertia differences of equally sized particles of different density to a different behavior of the aerosol streams powdered

Coating materials with identical grain size distribution lead. Therefore, it can be difficult to find funding procedures for a

specific D _{50 have been} optimized to transfer to powdered coating materials of different density. In certain embodiments, it is therefore preferred that the upper limit of the Span value be dependent on the Density of the powdered coating material according to formula V is corrected.

Span _0K = span _i (V)

Where Span ₀ K is the corrected upper span value, Span _{0 is} the upper span value, p _{A is} the density of aluminum (2.7 g / cm ³ ) and px is the density of the

used powdery coating material. However, it has also been found that the differences in powdered coating materials with a lower density than aluminum are only slight and an optimized selection of the powdered coating material in this respect does not bring about a noticeable improvement in the conveyability. For powdery

Coating materials having a density less than the density of aluminum are therefore used with an uncorrected upper span powdery coating material.

Coating processes which can be used according to the invention are known to the person skilled in the art under the name of cold gas spraying, thermal plasma spraying, non-thermal plasma spraying, flame spraying and high-speed flame spraying.

The cold gas spraying is characterized in that the powder to be applied is not melted in the gas jet, but that the particles are greatly accelerated and form a coating on the surface of the substrate due to their kinetic energy. Here are the various

Those skilled in the art are used as a carrier gas such as nitrogen, helium, argon, air, krypton, neon, xenon, carbon dioxide, oxygen or mixtures thereof. In certain variants, it is particularly preferred that are used as gas, air, helium or mixtures thereof. By a controlled expansion of the aforementioned gases in a corresponding nozzle gas velocities of up to 3000 m / s can be achieved. The particles can be accelerated up to 2000 m / s. In certain variants of cold gas spraying, however, it is preferred that they have particles, for example, speeds between 300 m / s and 1600 m / s, preferably between 1000 m / s and 1600 m / s, more preferably between 1250 m / s and 1600 m / s to reach.

A disadvantage, for example, the large noise, which is caused by the high speeds of the gas streams used.

In flame spraying, for example, a powder is converted into the liquid or plastic state by means of a flame and then applied as a coating to a substrate. Here, e.g. a mixture of oxygen and a combustible gas such as acetylene or hydrogen burned. In particular

Variants of flame spraying use part of the oxygen to convey the powdery coating material into the combustion flame. The particles reach in conventional variants of this method

Speeds between 24 to 31 m / s.

Similar to flame spraying is also at

For example, high-velocity flame spraying converts a powder into a liquid or plastic state by means of a flame. However, the particles are accelerated significantly faster compared to the aforementioned method. In specific examples of the aforementioned method, for example, a velocity of the gas stream of 1220 to 1525 m / s is called with a velocity of the particles of about 550 to 795 m / s. In other variants of this method, however, gas velocities of over 2000 m / s are achieved. In general, in conventional variants of the above method it is preferred that the speed of the flame be between 1000 and 2500 m / s. Furthermore, it is preferred in conventional variants that the flame temperature is between 2200 ° C and 3000 ° C. The temperature of the flame is thus comparable to the temperature during flame spraying. This is achieved by combustion of the gases under a pressure of about 515 to 621 kPa followed by the expansion of the combustion gases in a nozzle. Generally, it is believed that coatings produced thereby have a higher density compared to, for example, coatings obtained by the flame spraying process. The detonation / explosive flame spraying can be classified as subspecies of the

 High velocity flame spraying. Here, the powdery coating material is greatly accelerated by repeated detonations of a gas mixture such as acetylene / oxygen, for example, particle velocities of about 730 m / s are achieved. The

Detonation frequency of the method is in this case, for example, between about 4 to 10 Hz. In variants such as the so-called high frequency gas detonation spraying but also detonation frequencies are selected by about 100 Hz. The resulting layers should usually have a particularly high hardness, strength, density and good bonding to the substrate surface. A disadvantage of the aforementioned method, the increased security costs, and, for example, the large noise pollution due to the high

Gas velocities.

In thermal plasma spraying, for example, a primary gas such as argon is passed through a DC arc furnace at a rate of 40 l / min and a secondary gas such as hydrogen at a rate of 2.5 l / min, thereby generating a thermal plasma. Subsequently, the supply of, for example, 40 g / min of the pulverulent takes place Coating material with the aid of a carrier gas stream, which with a

Speed of 4 l / min is passed into the plasma flame. at

common variants of the thermal plasma spraying, the delivery rate of the powdery coating material is between 5 g / min and 60 g / min, more preferably between 10 g / min and 40 g / min.

In certain variants of the process it is preferred to use argon, helium or mixtures thereof as ionizable gas. The total gas flow is also preferably 30 to 150 SLPM (standard liters per minute) for certain variants. The electrical power used for the ionization of the gas flow without the heat energy dissipated as a result of cooling can be selected, for example, between 5 and 100 kW, preferably between 40 and 80 kW. Here, plasma temperatures between 4000 and a few 10000 K can be achieved.

In non-thermal plasma spraying, a non-thermal plasma is used to activate the powdery coating material. The plasma used here is, for example, with a barrier discharge or

Corona discharge generated at a frequency of 50 Hz to 1 MHz. In certain variants of non-thermal plasma spraying, it is preferred to operate at a frequency of 10 kHz to 100 kHz. The temperature of the plasma here is preferably less than 3000 K, preferably less than 2500 K and even more preferably less than 2000 K. This minimizes the technical complexity and keeps the energy input in the applied

Coating material as low as possible, which in turn is a gentle

Coating the substrate allowed. The magnitude of the temperature of the plasma flame is thus preferably comparable to that in flame spraying or high-speed flame spraying. Targeted choice of parameters also allows the generation of nonthermal plasmas with core temperatures below 1 173 K or even below 773 K in the core region. The measurement of Temperature in the core region occurs here, for example, with a thermocouple type NiCr / Ni and a tip diameter of 3 mm in 10 mm distance from the nozzle exit in the core of the exiting plasma jet at

Ambient pressure. Such non-thermal plasmas are particularly suitable for coatings of very temperature-sensitive substrates.

For producing coatings with sharp boundaries without the

If it is necessary to cover specific areas, it has proven to be advantageous, in particular, to design the outlet opening of the plasma flame such that the web widths of the coatings produced are between 0.2 mm and 10 mm. This allows a very accurate, flexible, energy-efficient coating with the best possible utilization of the coating material used. As a distance of the spray lance to the substrate, for example, a distance of 1 mm is selected. This allows for the greatest possible flexibility of the coatings while ensuring high-quality coatings.

 Conveniently, the distance between the spray lance and the substrate is between 1 mm and 35 mm.

As the ionizable gas, various gases known to those skilled in the art and mixtures thereof can be used in the non-thermal plasma process.

 Examples of these are helium, argon, xenon, nitrogen, oxygen, hydrogen or air, preferably argon or air. A particularly preferred ionizable gas is air. For example, to reduce the noise pollution, it may also be preferred here that the speed of the plasma flow is below 200 m / s. As a flow rate, for example, a value between 0.01 m / s and 100 m / s, preferably between 0.2 m / s and 10 m / s are selected.

In particular, it is preferred in certain embodiments, for example, the volume flow of the carrier gas is between 10 and 25 l / min, more preferably between 15 and 19 l / min.

According to a preferred embodiment, the particles of the powdered coating material are preferably metallic particles or metal-containing particles. In particular, it is preferred that the metal content of the metallic particles or metal-containing particles is at least 95% by weight, preferably at least 99% by weight, more preferably at least 99.9% by weight. In certain preferred embodiments, the metal or metals are selected from the group consisting of silver, gold, platinum, palladium, vanadium, chromium, manganese, cobalt, germanium, antimony, aluminum, zinc, tin, iron, copper, nickel, titanium, silicon , Alloys and mixtures thereof.

In particular, in certain of the foregoing embodiments, it is preferred that the metal or metals be selected from the group consisting of silver, gold, aluminum, zinc, tin, iron, copper, nickel, titanium, silicon, alloys, and mixtures thereof, preferably from the group consisting of silver, gold, aluminum, zinc, tin, iron, nickel, titanium, silicon, alloys and mixtures thereof. According to further preferred embodiments of the method according to the invention, the metal or metals of the particles of the

powdery coating material selected from the group consisting of silver, aluminum, zinc, tin, copper, alloys and mixtures thereof. As particularly suitable in specific embodiments

Particles have been found to be particularly metallic particles or metal-containing particles, in which the metal or metals are selected from the group consisting of silver, aluminum and tin.

In further embodiments of the invention, the powdered

Coating material of inorganic particles, preferably from the Group consisting of carbonates, oxides, hydroxides, carbides, halides, nitrides and mixtures thereof. Particularly suitable are mineral and / or metal oxide particles. In other embodiments, the inorganic particles are alternatively or additionally selected from the group consisting of carbon particles or

Graphite particles selected.

Another possibility is the use of mixtures of the metallic particles and the aforementioned inorganic particles, such as

for example, mineral and / or metal oxide particles, and / or the particles selected from the group consisting of carbonates, oxides, hydroxides, carbides, halides, nitrides, and mixtures thereof. Further, the powdery coating material may comprise or consist of glass particles. In certain embodiments, it is particularly preferred that the powdered coating material be coated

Glass particles comprises or consist of them. In addition, the powdered coating material includes certain

 Embodiments organic or inorganic salts or consists of them.

In still other embodiments of the present invention, the powdered coating material comprises or consists of plastic particles. The abovementioned plastic particles are formed from, for example, pure or mixed homo-, co-, block- or prepolymers or mixtures thereof. Here, the plastic particles may be pure crystals or be mixed crystals or have amorphous phases. The plastic particles can be obtained, for example, by mechanical comminution of plastics. In certain embodiments of the method according to the invention, the powdery coating material comprises or consists of mixtures of particles of different materials. In certain preferred

Embodiments consists of the powdery coating material

in particular from at least two, preferably three, different particles of different materials.

The particles can be produced by different methods.

For example, the metal particles can be obtained by atomization or atomization of molten metal. Glass particles can be produced by mechanical comminution of glass or else from the melt. In the latter case, the molten glass can also be atomized or atomized. Alternatively, molten glass can also be used on rotating elements,

For example, a drum, be divided.

Mineral particles, metal oxide particles and inorganic particles selected from the group consisting of oxides, hydroxides, carbonates, carbides, nitrides, halides and mixtures thereof can be obtained by comminuting the naturally occurring minerals, rocks, etc. and subsequently size-classified.

Size classification can be carried out, for example, by means of cyclones, air separators, screening, etc.

In certain embodiments of the present invention, the easily deformable particles of the invention are the powdery particles

Coating material has been provided with a coating to

For example, to provide improved oxidation stability during storage of the powdered coating material. In certain preferred embodiments of the present invention, the aforesaid coating may comprise a metal or may consist of a metal. Such a coating of a particle may be closed or particulate, with closed structure coatings being preferred. The layer thickness of such a metallic coating is preferably less than 1 μm, more preferably less than 0.8 μm, and even more preferably less than 0.5 μm. In certain embodiments, such

Coatings a thickness of at least 0.05 μιτη, more preferably of at least 0.1 μιτι on. Especially in certain embodiments

Preferred metals for use in any of the foregoing coatings, preferably as major constituents, are selected from the group consisting of copper, titanium, gold, silver, tin, zinc, iron, silicon, nickel and aluminum, preferably selected from the group consisting of gold, silver , Tin and zinc, more preferably from the group consisting of silver, tin and zinc. The term main constituent in the sense of the abovementioned coating denotes that the metal in question or a mixture of the abovementioned metals represents at least 90% by weight, preferably 95% by weight, more preferably 99% by weight, of the metal content of the coating. It must be understood that in the case of partial oxidation, the oxygen content of the corresponding

Oxide layer is not included. The production of such metallic coatings can be carried out, for example, by means of gas-phase synthesis or wet-chemical processes. In further specific embodiments, the particles of the powdery coating material according to the invention are additionally or alternatively coated with a metal oxide layer. Preferably, this metal oxide layer consists essentially of silicon oxide, aluminum oxide, boron oxide, zirconium oxide, cerium oxide, iron oxide, titanium oxide, chromium oxide, tin oxide, molybdenum oxide, their hydrated oxides, their hydroxides and mixtures thereof. In certain preferred Embodiments, the metal oxide layer consists essentially of

Silicon oxide. The aforementioned term "consists essentially of" in the sense of the present invention means that at least 90%, preferably

at least 95%, more preferably at least 98%, even more preferably at least 99%, and most preferably at least 99.9% of the

 Metal oxide layer consists of the aforementioned metal oxides, in each case based on the number of particles of the metal oxide layer, wherein optionally contained water is not included. The determination of

Composition of the metal oxide layer can be carried out by methods known to the person skilled in the art, for example sputtering in combination with XPS or TOF-SIMS. In particular, it is with certain of the aforementioned

Embodiments preferred that the metal oxide layer is not an oxidation product of an underlying metal core. The application of such a metal oxide layer can be carried out, for example, by the sol-gel method.

In certain preferred embodiments, the substrate is selected from the group consisting of plastic substrates, inorganic substrates,

Cellulose-containing substrates and mixtures thereof.

The plastic substrates may be, for example, plastic films or molded plastic. The shaped bodies can have geometrically simple or complex shapes. The plastic molding may be, for example, a component of the automotive industry or the construction industry.

The cellulose-containing substrates may be cardboard, paper, wood, wood-containing substrates, etc. The inorganic substrates may be, for example, metallic substrates, such as metal sheets or metallic moldings or ceramic or mineral substrates or moldings. The inorganic substrates may also be solar cells or silicon wafers onto which, for example, electrically conductive coatings or contacts are applied.

Substrates made of glass, such as glass panes, can also be used as inorganic substrates. The glass, in particular glass panes, can be provided using the method according to the invention, for example with electrochromic coatings.

The coated by the process according to the invention substrates are suitable for very different applications. In certain embodiments, the coatings have optical and / or electromagnetic effects. Here, the coatings

Cause reflections or absorptions. Furthermore, the coatings may be electrically conductive, semi-conductive or non-conductive. Electrically conductive layers may, for example, be in the form of

 Conductor tracks are applied to components. This can be used, for example, to enable the power supply in the context of the electrical system in a motor vehicle component. Furthermore, however, such a track may also be shaped, for example, as an antenna, as a shield, as an electrical contact, etc. This is for example particularly advantageous for RFID applications (radio frequency identification). Furthermore, inventive

Coatings are used for example for heating purposes or for specific heating of special components or special parts of larger components. In further particular embodiments, the coatings produced serve as slip layers, diffusion barriers for gases, and

Liquids, wear and / or corrosion protection coatings. Furthermore, the coatings produced can influence the surface tension of liquids or have adhesion-promoting properties.

The coatings produced according to the invention can furthermore be described as

Sensor surfaces, for example as a human-machine interface (HMI: Human Machine Interface), for example in the form of a touch screen (touch screen) can be used. Likewise, the coatings may be used to shield from electromagnetic interference (EMI) or to protect against

electrostatic discharges (ESD) are used. The coatings can also be used to effect electromagnetic compatibility (EMC).

Furthermore, layers can be applied by the use of the particles according to the invention, which are applied, for example, to increase the stability of corresponding components after their repair. An example is repairs in the aircraft sector, for example, a loss of material due to

Processing steps must be compensated or a coating is to be applied, for example, for stabilization. This proves difficult for aluminum components, for example, and usually requires finishing operations such as sintering. By means of the invention

On the other hand, methods can be applied to adherent coatings under very mild conditions, even without post-processing steps such as sintering are required.

In yet other embodiments, the coatings serve as electrical contacts and permit electrical connection between different materials. The skilled person is aware that the above with regard to

Specifications according to the invention with respect to the powdered coating material and the particles contained therein, correspondingly also for the use of the pulverulent

 Coating material and the particles contained therein apply, and vice versa.

pictures

Figures 1 to 4 show a wafer, which first by means of

 Solar contact paste and was subsequently coated by means of non-thermal plasma spraying, wherein a powdered copper coating material according to the invention was used.

Examples

Used materials and methods. The determination of the size distribution of the particles used

Pulverformigen coating materials using a HELOS device (Sympatec, Germany). For the measurement, 3 g of the powdery coating material was placed in the meter and sonicated for 30 seconds prior to measurement. For dispersion, a Rodos T4.1 dispersion unit was used, the primary pressure being 4 bar. The evaluation was carried out with the standard software of the device.

The inventive method will now be explained in more detail with reference to the following examples, without being limited to the examples. Example 1: flame spraying of copper particles

By means of a Flammsphtzanlage the company CASTOLIN were using an acetylene / oxygen flame spherical copper particles, the relative

Deformability of about 0.6, with a D ₅₀ value of 54 μηη

(Comparative Example 1 .1), and copper particles with a relative

Deformability factor of 0.03 and a D ₅₀ value of 55 μηη

(Inventive Example 1 .2) applied to a metal sheet. The resulting sheets were examined by SEM.

Already during spraying of the invention to be used pul verförmigen coating material shows that significantly less material from the plate cums. The coated sheet according to the invention is much more homogeneous in terms of its appearance and feel. SEM images of the surfaces show the formation of larger uniform areas of the coating, while the surface of the comparative example is characterized by a plurality of separated particles. Furthermore, the cross-section shows that cavities contained in the coating of the sheet according to the invention are significantly smaller. Example 2: Non-thermal plasma spraying of copper particles

The application of the powdery coating material was carried out by means of a Plasmatron plant from Inocon, Attnang-Puchheim, Austria. Argon was used as the ionizable gas. Here were

Standard process parameters used.

Here, a non-inventive powdered Beschichtungsmatenal having a relative deformability factor of 0.6 and a D ₅₀ of 25 μητι, and a powdered Beschichtungsmatenal invention with a relative deformability factor of 0.009 and a D ₅₀ of 35 μηη was used. When The substrate was a wafer coated with solar contact paste. It has been observed that the higher energies normally chosen by those skilled in the art for applying the powdered coating materials may result in wafer damage. However, under gentler conditions, no satisfactory coatings were achieved with a powdery coating material having a relative ductility factor of 0.6 because, for example, the adhesion of the coatings was no longer satisfactory. The powdered coating materials of the invention, however, allow application even under very mild conditions. For example, a very low deposition rate and / or a very low temperature can be selected. Figures 1 to 4 show various sections of an applied powdered according to the invention

Coating material. The applied coating adapts well to the uneven surface structure of the solar contact paste and even partially penetrates into it without impairing the structure of the solar contact paste or even damaging the wafer.

Claims

claims

Use of a particle-containing pulverulent coating material in a coating process selected from the group consisting of cold gas spraying, flame spraying, high-velocity flame spraying, thermal plasma spraying and non-thermal plasma spraying, the particles having a relative ductility factor V _m of at most 0.1 and the relative ductility factor according to formula (I ) is defined:

where c / is the average minimum thickness of the particles, measured vertically to and in the middle half of the longitudinal axis of the particles, and D _{50 is} the mean diameter of the volume-average particle size distribution.

Use according to claim 1, wherein the relative deformability factor is defined taking into account the Mohs hardness of silver-related Mohs hardness of the particles according to formula (II):

where H is the Mohs hardness of the particles and H _{Ag is} the Mohs hardness of silver. Use according to one of claims 1 or 2, wherein the relative deformability factor of the powdery coating material is at most 0.01.

Use according to one of claims 1 to 3, wherein the particles of the powdery coating material have a technical elastic limit of more than 45 N / mm ² .

Use according to one of claims 1 to 4, wherein the measured in [K] melting point of the particles of the coating material at most 60% of the temperature measured in [K] of the in

Coating process used directed to the substrate

Medium is.

Use according to any one of claims 1 to 5, wherein the particles comprise or are metal particles and the metal is selected from the group consisting of silver, gold, platinum, palladium, vanadium, chromium, manganese, cobalt, germanium, antimony, aluminum, zinc, Tin, iron, copper, nickel, titanium, silicon, alloys and mixtures thereof.

Use according to any one of claims 1 to 6, wherein the

Coating method is selected from the group consisting of flame spraying and non-thermal plasma spraying, and preferably is non-thermal plasma spraying.

Use according to one of claims 1 to 7, wherein the powdery coating material has a particle size distribution with a D ₅₀ value from a range of 1, 5 to 84 μηη.

9. Use according to one of claims 1 to 8, wherein the powdery coating material has a particle size distribution with a Di ₀ value from a range of 3.7 to 26 μητι, a D ₅₀ value from a range of 6 to 49 μΐη and a D ₉₀ value from a range of 12 to 86 μηη.

Use according to any one of claims 1 to 9, wherein the span of the powdered coating material is at most 2.9, wherein the chip is defined according to formula (III):

1 1. Use according to one of claims 1 to 10, wherein the particles of the powdery coating material are at least partially coated.

12. A method for coating a substrate selected from the group consisting of cold gas spraying, flame spraying,

 High-speed flame spraying, thermal plasma spraying and non-thermal plasma spraying,

 characterized,

 that the method comprises the following step:

Introducing a particle-containing powdered coating material into a medium directed onto a substrate to be coated, wherein the particles have a relative ductility factor V _m of at most 0.1 and the relative ductility factor according to formula (I) is defined: where c is the average minimum thickness of the particles, measured vertically to and in the middle half of the longitudinal axis of the particles, and D _{50 is} the mean diameter of the volume-average particle size distribution.

The method of claim 12, wherein the method is selected from the group consisting of flame spraying and non-thermal

 Plasma spraying, and preferably non-thermal plasma spraying.

Method according to one of claims 12 or 13, wherein said

 pulverulent coating material is conveyed as an aerosol.

15. The method according to any one of claims 12 to 14, wherein the on the

 Substrate directed medium is air or generated from air.