Coating plant for coating planar objects and method for coating planar objects - Patents.com

Abstract

The present invention relates to a coating plant (1) for coating a planar object (2), for example a strip. The strip is transported using transport rollers (3a, 3b). The coating plant (1) comprises: A vacuum chamber (4); an apparatus (6) for the deposition of a material comprising an evaporation section (7) and a nozzle section (8); The nozzle portion (8) comprises a nozzle (9) having a nozzle outlet. The nozzle outlet may have an extension portion (D0). The nozzle (9) is mounted rotatably in a direction (10). A further concept is a method for coating a planar object.

Description

[Technical field]

[0001] The present invention relates to a coating plant for coating planar objects and to a method for coating planar objects. [Background technology]

[0002] Methods based on the so-called vapor deposition principle are known for coating planar objects, for example strips, in particular strip metals such as strip steel. Vapor deposition is based on the principle of coating the surface of a planar object, which may be, for example, strip steel or a glass plate, by depositing a material present in the gas phase. For this purpose, a material is first provided as a starting material. The starting material is then introduced into the gas phase. Components of the material present in the gas phase, in particular atoms and / or ions, precipitate on the surface to be coated, thereby forming the coating.

[0003] Known deposition methods include the so-called Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD) and the so-called Arc Evaporation. These methods differ in particular in the mechanism used to produce the gas phase.

[0004] One advantage of deposition is that it allows for the very economical production of coatings whose properties can be greatly influenced within a wide range of properties. Another advantage is that deposition is suitable for producing coatings of a wide variety of materials. Deposition is also suitable for producing coatings that contain, for example, high melting point materials. Deposition also facilitates coatings in which the material exists in a metastable phase and therefore has certain properties, such as mechanical or optical properties, that are not present in a stable phase state.

[0005] A recently developed variant of physical vapor deposition is known to those skilled in the art under the name of jet vapor deposition, or JVD for short. Jet vapor deposition is based on the principle of evaporating the starting material in the evaporation section of an apparatus for depositing materials, for example in an evaporator designed as a crucible, and directing the material present in the gas phase at a relatively high pressure through a nozzle section in the direction of the surface to be coated by vapor deposition. For this purpose, the surface to be coated by vapor deposition is usually placed in an atmosphere of negative pressure with respect to the atmosphere prevailing in the evaporation section. In many cases, the negative pressure is a vacuum with a residual gas pressure of, for example, 0.1 mbar to 20 mbar, preferably less than 1 mbar. The JVD method reveals its advantages in particular in the large-area coating of planar objects of strip metal, especially strip steel. The advantage of JVD is that the relatively high pressure with which the material present in the gas phase is directed to the surface to be coated by vapor deposition makes coating at high strip speeds easy and, as a result, extremely economical.

[0006] WO 2016 / 042079 discloses an apparatus in which starting materials can be introduced into the gas phase and can then be deposited on the surface to be coated by vapor deposition. The materials used to form the respective coatings are, for example, in the form of wires or strips. In a pre-evaporation section upstream of the evaporation section, the starting materials are introduced within the range of influence of an electric arc, preferably two wires or two strips of starting material are present, one of which is connected as a cathode and one of which is connected as an anode to a direct current voltage source, and a voltage sufficient to form an arc is set using the direct current voltage source. The material melted and / or evaporated by the energy from the arc flows by a gas flow of gas or gas mixture into the evaporation section designed as a chamber, the walls of which have a temperature above the evaporation temperature of the basic components of the material used in the coating process. In the chamber, the components of the material are completely evaporated and then pass through an opening in the chamber into a nozzle section through which they are directed in the direction of the surface to be coated. The components of the material act on the surface to be coated and form the coating there.

[0007] The JVD described at the beginning and the exemplary embodiment of the device for the deposition of materials described in WO 2016 / 042079 are both two examples of deposition, where in the case of WO 2016 / 042079 the starting material in the evaporation section is additionally introduced into its gas phase by evaporation by an upstream pre-evaporation section for arc evaporation and is then led through the nozzle section to the surface to be coated. The movement of particles, in particular atoms and / or ions, present in the gas phase is at least substantially, preferably completely, brought about by the pressure difference between the evaporation section and the space in which the planar object to be coated is placed or led through, for example a vacuum chamber. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2016 / 042079 [Non-patent literature]

[0009] [Non-Patent Document 1] Komarenko, P., et al. “Handbook of Deposition Technologies for Films and Coatings Science, Applications and Technology”, 2010, pp. 881-901, [Retrieved May 30, 2022], Internet<URL:https: / / doi.org / 10.1016 / B978-0-8155-2031-3.00018-1> Summary of the Invention [Problem to be solved by the invention]

[0010] When coating planar objects with an apparatus for the deposition of materials by evaporation, one challenge is to obtain a good uniformity of the layer thickness of the coating in the lateral direction of the planar object, for example along the entire strip width. Furthermore, it is desirable to be able to provide a good uniformity of the layer thickness distribution along the entire lateral extension. [Means for solving the problem]

[0011] This object is achieved by a coating plant for coating planar objects having the features of claim 1 and by a method for coating planar objects having the features of claim 12.

[0012] The coating plant according to the invention serves the purpose that planar objects can be coated. In particular, a strip, preferably a strip metal such as strip steel, can be provided as the planar object. The coating process is carried out with a material present in the gas phase, in particular based on one of the mechanisms described at the beginning.

[0013] The coating plant comprises a vacuum chamber into which the planar object to be coated can be introduced.

[0014] The coating plant also comprises an apparatus for the deposition of the material. The deposition apparatus comprises in particular an evaporation part and a nozzle part.

[0015] The evaporation section is designed, for example, as an evaporation crucible and preferably has a cylindrical, in particular circular-cylindrical, section. The evaporation section is preferably made partially or completely of graphite or carbon fiber reinforced carbon (CFC). In order to heat the evaporation section to a temperature above the evaporation temperature of the starting material, the base and / or the walls, preferably all walls, of the evaporation section are designed to be heatable, for example by means of heating coils.

[0016] The terms "gas phase" and "evaporation" are used throughout the specification as they are typical in the field of the described technology. The term "gas phase" in this case includes the fact that a low weight fraction of the material present in the gas phase, for example up to 30% by weight, preferably 10% by weight or less, may not be present in the gas phase in the physical sense, but instead may exist as an aerosol and / or as clusters. The term "evaporation" also includes that, depending on the material and technology used, the particles may be at least partially transferred to the gas phase by other mechanisms, for example sublimation. Thus, the term "evaporation" additionally includes further mechanisms, in particular sublimation, in addition to evaporation in the strict physical sense, i.e., "liquid phase → gas phase" transition.

[0017] The nozzle part is indirectly or directly connected to the evaporation part. The nozzle part is arranged in the vacuum chamber and has a nozzle with an opening through which the components of the material present in the gas phase can flow out of the nozzle. The nozzle outlet is oriented in the coating plant such that the gas phase particles leaving the nozzle outlet are directed towards the surface to be coated, i.e. where the planar object is located. By passing the planar object through the vacuum chamber, the surface of the planar object to be coated is coated with the condensed material that is continuously applied to and deposited on the surface.

[0018] According to the invention, it is provided that the nozzle is rotatably mounted. The rotatable mounting serves to change the orientation of the nozzle outlet relative to the surface to be coated. Since the nozzle is rotatably mounted and the orientation of the nozzle outlet relative to the surface to be coated is variable, the way in which the material present in the gas phase is directed to the surface of the planar object can be influenced or adjusted in a targeted manner. Particularly preferred are embodiments in which the nozzle part is rotatably mounted so as to rest against the evaporation part, i.e. the evaporation part acts as a sliding bearing for the nozzle part. In such an embodiment, in particular the evaporation part made partially or completely from graphite and / or CFD offers the advantage that carbon acts as a natural lubricant. Alternatively or additionally, it is also possible to use powdered and / or pasty graphite as a lubricant and to introduce for this purpose between the adjacent surfaces of the evaporation part and the nozzle part that slide against each other, regardless of the material of which the evaporation part is composed.

[0019] The nozzle outlet can be designed, for example, as a slot. It is particularly preferred that the nozzle outlet, at least in the part in which the coating process takes place, is in a plane parallel to the surface to be coated, and particularly preferably the nozzle can assume a position in which the slot is located perpendicular to the direction of movement (also the conveying direction) of the surface to be coated and is rotatable around an axis of rotation perpendicular to the surface to be coated. In particular, it can be provided that the length of the slot-shaped nozzle is selected such that, at an angle α of 90 degrees between the conveying direction and the slot-shaped nozzle, for a strip having the maximum width for the feed-through for which the vacuum chamber is designed, the width of the planar object, for example the strip width, is completely covered. By adjusting the angle α, the effective coating width perpendicular to the strip travel direction can be changed by a factor sin(α). The device thus provided is particularly suitable for facilitating with high efficiency, in particular when coating planar objects as intended, strips having a strip width smaller than the longitudinal extension of the slot-shaped nozzle outlet, so that no material present in the gas phase is deposited in the vacuum chamber beyond the two strip ends without being utilized for the coating of the surface, or a proportion of material exceeding the permissible amount is deposited.

[0020] By providing a rotatable nozzle, two advantages in particular are achieved: on the one hand, the supplied starting material is deployed and used as efficiently as possible, and on the other hand, contamination of the vacuum chamber is avoided when coating narrow strips. More generally, the coating plant according to the invention and its developments achieve a high degree of flexibility with regard to the possible width of the surface to be coated perpendicular to the conveying direction, without compromising economy and efficiency.

[0021] In a preferred embodiment, the object to be coated is a strip, in particular a strip made of metal, for example steel, and the coating plant has a belt conveying device for conveying the strip, preferably comprising a first conveying roller device at a first end of the vacuum chamber and a second conveying roller device at a second end of the vacuum chamber, and the strip passes through the nozzle, is conveyed between the first and second ends and passes through the vacuum chamber.

[0022] In a preferred embodiment, the strip is guided in a heated channel in the region of the nozzle outlet to prevent excessive high cooling of the gas between the nozzle outlet and the deposit on the strip and the resulting premature condensation.

[0023] In a preferred embodiment, the nozzle is mounted such that, when the nozzle rotates, the nozzle outlet performs a rotational movement in a plane parallel to the surface, as a result of the rotation performed parallel to the surface, i.e. the nozzle outlet describes the surface in a plane parallel to the surface to be coated during the rotation, and a homogeneous coating of the surface to be coated in the transverse direction, i.e. perpendicular to the conveying direction, is guaranteed, regardless of the rotation angle at which the nozzle rotates relative to the conveying direction.

[0024] It is particularly preferred that the axis of rotation for rotating the nozzle is oriented perpendicular to the surface, which can always be implemented with conventional design means by a person skilled in the art entrusted with carrying out this development by correspondingly arranging the deposition device in the vacuum chamber, taking into account the transport of the planar object.

[0025] Particularly preferred are embodiments in which the nozzle outlet located in the nozzle is configured in such a way that the material in the gas phase emerging from the nozzle outlet leaves the nozzle in the direction of the rotation axis, i.e. in the case of, for example, a rotation axis oriented perpendicular to the surface to be coated, the material in the gas phase acts on the surface in a direction perpendicular to the surface to be coated. It is also very particularly preferred if the nozzle outlet is additionally shaped in such a way that the main exit direction of the material in the gas phase passes perpendicularly through the area represented by the nozzle outlet.

[0026] In a particularly preferred development of the coating plant, the nozzle has a cylindrical, preferably circular-cylindrical, external mold section which is provided with teeth at the circumferential portion of its circumference or over its entire circumference. The teeth engage with a drivable counterelement which engages with the teeth, such that the nozzle is rotated by driving the counterelement. The term "external mold section" denotes a part of the nozzle part, the name being related to the fact that the outer casing of the external mold section has a function due to its shape, for example with teeth.

[0027] The counter element is preferably a pinion coupled to a shaft. The shaft is preferably guided out of the vacuum chamber by a suitable sealing element of known design. The shaft is coupled to a rotary drive for rotating the shaft and thus the nozzle. In other words, the nozzle, in particular the nozzle outlet, can be rotated from outside the vacuum chamber by a shaft inserted into the vacuum chamber via teeth engaging with the pinion. In a particularly preferred development of the coating plant, the nozzle has a cylindrical, preferably circular-cylindrical, outer mould part which is fitted on or is provided with a sprocket. The sprocket is engaged with a drivable counter element which engages with the sprocket, such that the nozzle is rotated by driving the counter element.

[0028] The counter element is preferably a pinion coupled to a shaft. The shaft is preferably guided out of the vacuum chamber by a suitable sealing element of known design. The shaft is coupled to a rotary drive for rotating the shaft and thus the nozzle. In other words, the nozzle, in particular the nozzle outlet, can be rotated from outside the vacuum chamber by a shaft inserted into the vacuum chamber via a sprocket engaging the pinion. In a particularly preferred embodiment, the shaft with the pinion and the rotation axis of the nozzle are oriented parallel to one another, which is associated with the advantage of a potentially structural implementation of the coating plant. Particularly preferred is to provide both the pinion and the sprocket with spur teeth, which results in a particularly easy to implement and mechanically robust embodiment.

[0029] In an embodiment with a sprocket, the sprocket is provided with teeth, for example on the circumferential part of its circumference or, for example, completely on its circumference. In a preferred embodiment, the nozzle and the sprocket are designed to be thermally insulated from each other by thermal insulation means arranged between the outer mold part of the nozzle and the sprocket. This ensures that the sprocket and the drivable counter element engaging the sprocket, as well as further elements that may be present and connected to it, such as the above-mentioned shaft withdrawn from the vacuum chamber, are protected from premature loss of structural integrity due to high temperatures. This is particularly advantageous in light of the fact that the evaporation part, which is in indirect or direct contact with the nozzle, is heated to evaporate the material and that the temperature used can assume very high values ​​as a function of the material to be evaporated, depending on its evaporation temperature.

[0030] The thermal insulation means is preferably designed as an insulating ring. Particularly preferably, the insulating ring comprises or consists of a ceramic material. An example of a possible ceramic material is aluminium oxide (Al2O3). The advantage of using a ceramic material is its high resistance to chemical degradation and its low thermal conductivity.

[0031] In an alternative embodiment, the counter element is designed as a worm shaft coupled to a shaft withdrawn from the vacuum chamber. The shaft is coupled to a rotary drive, the shaft being designed to be rotatable, the rotation of the shaft resulting in a rotation of the nozzle. The shaft is preferably oriented perpendicular to the axis of rotation of the nozzle, preferably further tangentially to the teeth, e.g. sprocket, which are toothed in a complementary manner to the worm shaft, i.e. with helical teeth. The shaft preferably has a coolant feedthrough through which a coolant can be passed to cool the shaft. In this embodiment, in contrast to the embodiment described above, the sprocket is not insulated from the evaporating part by insulating means, instead a direct cooling of the shaft, preferably the worm shaft, is brought about by passing a coolant through a coolant feedthrough arranged in the shaft, which is preferably a component of the coolant circuit.

[0032] Particularly preferably, the shaft is provided with a coupling means, e.g. a universal joint, by which the shaft is given a degree of freedom of movement in the lateral direction. The shaft can be moved out of engagement with the teeth, e.g. a sprocket, and back into engagement with the teeth, e.g. a sprocket, by means of a coupling piece and a lateral drive means coupled thereto, the degree of freedom of movement being preferably oriented perpendicular to the axis of rotation of the nozzle. By providing the mobility of the worm shaft away from the teeth, e.g. away from the sprocket and towards the sprocket, the thermal load on the worm shaft and the shaft can be reduced by shortening the contact time during periods when actual contact is required to cause the rotational movement of the nozzle, and by moving the worm shaft away from the teeth, e.g. away from the sprocket, during other periods. In a special case, it is provided that the shaft with the worm shaft has both the coolant feedthrough described in the two previous paragraphs and the freedom of movement described in the previous paragraph in a direction perpendicular to the axis of rotation of the nozzle, and in addition does not have any explicit thermal insulation means between the sprocket and the outer mould section, i.e. it is possible to minimise periods of thermal loading on the worm shaft and the shaft driving it, as a result of which the additional advantage that thermal insulation means can be dispensed with is achieved. In a particularly specific embodiment, the teeth are realised as a sprocket, which is an integral part of the outer mould section.

[0033] Particularly preferably, the axis of rotation is furthermore movable in a direction perpendicular to the axis of rotation.

[0034] Alternatively or additionally, the nozzle outlet can be adjusted eccentrically with respect to the axis of rotation, i.e. the nozzle inlet and / or the axis of rotation can be adjusted such that the axis of rotation is not at the point of symmetry of the nozzle outlet. Taking a slot-shaped nozzle outlet as an example, this means, for example, that the axis of rotation preferably intersects the nozzle outlet but divides it into two longitudinal parts of different lengths.

[0035] For example, the nozzle part has at least one closing means for partially or completely closing the nozzle outlet, i.e. a mechanical means that can temporarily at least partially close the nozzle outlet. Partial closing of the nozzle outlet changes the symmetrical position of the rotation axis relative to the nozzle outlet to an asymmetrical position of the rotation axis relative to the nozzle outlet, thereby adjusting the eccentricity of the rotation axis relative to the part of the nozzle outlet that remains open. In this way, the adjustability of the eccentricity is brought about by or in proportion to changing the surface area of ​​the nozzle outlet through which the material discharged from the nozzle outlet passes.

[0036] To adjust the nozzle outlet, a closing means, for example designed as a sliding flap, can be provided to partially close the nozzle outlet from one end, so that the nozzle outlet is shorter on one side of the rotation axis than on the other side, i.e. the rotation axis is arranged eccentrically with respect to the resulting nozzle outlet. In such a case, by rotating the shaft and adjusting the longitudinal extension of the rotation axis that is projected onto the surface to be coated, the adaptation of the coating can be adjusted even more flexibly, whereby a flexible selection of the planar objects to be coated, in particular strips, is also ensured.

[0037] As an alternative or additional measure for providing an eccentric movement of the nozzle outlet, a specific embodiment can also be provided in which, at the toothed peripheral portion, preferably the toothed peripheral portion of the sprocket, the outer mold part is circular-cylindrical with a peripheral portion, preferably the toothed peripheral portion of the sprocket, having an axis of rotation at the central axis of the teeth, and furthermore the axis of rotation is arranged eccentrically with respect to the nozzle outlet. The provision that the outer mold part at the toothed peripheral portion, for example of a sprocket, is circular-cylindrical with an axis of rotation at the central axis of the toothed peripheral portion, for example of a sprocket, is to be understood as meaning that the peripheral portion represents a part of a toothed circular cylinder, for example of a sprocket, the axis of which corresponds to the axis of rotation of the nozzle part. In addition to this provision, if necessary the axis of rotation is displaced eccentrically with respect to the nozzle outlet of the nozzle part. The eccentric displacement of the axis of rotation with respect to the nozzle outlet of the nozzle part is to be understood as preferably such that the axis of rotation does not intersect with the nozzle outlet or, if the axis of rotation does intersect with the nozzle outlet, the intersection of the axis of rotation with the nozzle outlet is not a symmetrical point of the nozzle outlet. In the specific case where the nozzle outlet is designed as a slot, the eccentric displacement of the rotation axis of the nozzle part relative to the nozzle outlet is preferably understood to be such that the rotation axis does not intersect the nozzle outlet or, if it does, the intersection point of the rotation axis does not halve the slot in the longitudinal direction of the slot. In a particularly advantageous manner, the eccentric rotation of the slot-shaped nozzle outlet has the effect that, in the case of a particularly preferred embodiment, the length of the slot corresponds to at least 20 times, preferably 100 times, the slot width, and that the rotation axis does not intersect the nozzle outlet or, if it does, the intersection point of the rotation axis divides the slot into two parts, the longer part being at least 110 percent, preferably at least 120 percent, of the length of the shorter part.

[0038] As already mentioned above, the term "outer mould section" refers to a part of the nozzle part, the name being related to the fact that the outer casing of the outer mould section is provided with features due to its shape, e.g. teeth. In an embodiment with a sprocket, the outer mould section is for example the part of the nozzle part in the axial direction that fits onto the sprocket.

[0039] Alternatively or additionally, the eccentric orientation of the rotation axis relative to the nozzle outlet can also be implemented in a simple manner in the design by the nozzle outlet being positioned accordingly, for example by the outer mould part being circular-cylindrical with the rotation axis on its axis, but the nozzle outlet being spaced apart from the rotation axis, or by the rotation axis intersecting the nozzle outlet but not halving it.

[0040] In a preferred embodiment, the device for deposition of the material is a jet deposition plant, the evaporation section being preferably designed as a crucible. The skilled artisan will understand the term "jet deposition plant" as a plant in which the coating material is brought into the gas phase using heat and then transported to the substrate in a carrier gas flow, typically an inert gas, preferably at a gas flow velocity above the speed of sound, particularly preferably above 500 m / s. This mode of operation is described, for example, in the review Handbook of Deposition Technologies for Films and Coatings Science, Applications and Technology, 2010, pp.881-901, https: / / doi.org / 10.1016 / B978-0-8155-2031-3.00018-1 (link to the filing date). The present invention can be realized using such a jet deposition plant.

[0041] In an alternative preferred embodiment, a pre-vaporization section is arranged upstream of the evaporation section, which pre-vaporization section in particular comprises a spray head with a carrier gas flow supply to the spray head and an injection tube leading from the spray head to the evaporation section. The starting material is preferably fed to the spray head in the form of a wire or strip. The starting material is processed in the spray head. This means that the starting material is evaporated and / or separated from the starting material as particles present in the liquid phase, preferably by arc evaporation between the starting material connected as cathode and the starting material connected as anode. The processed starting material is not completely present in the gas phase, but in particular consists of a mixture of gas phase and liquid particles or partly liquid particles, which mixture is suitable to be led to the evaporation section in order to be re-evaporated there, i.e. to be completely or almost completely converted into the gas phase by the heating carried out there.

[0042] The evaporation section is preferably designed as a crucible. The evaporation section is heated to convert the treated starting material into the gas phase. The temperature to which the evaporation section is heated depends on the coating material, but in general it must be higher than the evaporation temperature of the treated starting material. The evaporation section is preferably designed as a crucible designed as a cyclone, since the cyclone shape is a space-saving design that allows efficient directing of the gas flow through the crucible. A further advantage of the crucible designed in the form of a cyclone is its high reliability of almost completely evaporating the material flowing through it, thereby ensuring that the deposited coating is of high quality, and if used properly, impacts on the strip by coating material still present in the liquid phase can be virtually eliminated.

[0043] Another concept relates to a method for coating a planar object with a material present in the gas phase, for which a coating plant of the type mentioned at the beginning or one of its developments is used. The longitudinal extension of the nozzle, designed for example as a slot, is greater than the width of the planar object in its transverse direction (transverse direction: direction on the surface perpendicular to the direction of travel, e.g. the direction of the strip). The orientation of the nozzle with respect to the surface to be coated is changed by rotating the nozzle so that the entire transverse extent of the surface to be coated is coated with the material coming out of the nozzle outlet and at least at one end, preferably at both ends, the material directed over the surface does not exceed the maximum permitted overhang.

[0044] Similar to what has been described above, according to one variant, it can be provided that the outer mould part of the nozzle, at least in the peripheral part having the teeth, is circular-cylindrical and has an axis of rotation on the central axis of the peripheral part, but that the axis of rotation is also arranged eccentrically with respect to the nozzle outlet.

[0045] For example, according to one variant, it can be provided that the outer mold part of the nozzle, at least in the part having the sprocket, is circular-cylindrical and has an axis of rotation on the central axis of the sprocket, but the axis of rotation is also arranged eccentrically with respect to the nozzle outlet.

[0046] For example, the nozzle part can be provided with at least one closing means for partially or completely closing the nozzle outlet, i.e. a mechanical means capable of temporarily closing the nozzle outlet at least partially. With partial closure of the nozzle outlet, the symmetrical position of the rotation axis relative to the nozzle outlet is changed to an asymmetrical position of the rotation axis relative to the nozzle outlet, whereby the eccentricity of the rotation axis relative to the part of the nozzle outlet that remains open is adjusted. In this way, the adjustability of the eccentricity is brought about by or in proportion to the change in the surface area of ​​the nozzle outlet through which the material discharged from the nozzle outlet passes.

[0047] To adjust the nozzle outlet, a closing means, for example designed as a sliding flap, can be provided to partially close the nozzle outlet from one end, so that the nozzle outlet is shorter on one side of the rotation axis than on the other side, i.e. the rotation axis is arranged eccentrically with respect to the resulting nozzle outlet. In such a case, by rotating the shaft and adjusting the longitudinal extension of the rotation axis that is projected onto the surface to be coated, the adaptation of the coating can be adjusted even more flexibly, whereby a flexible selection of the planar objects to be coated, in particular strips, is also ensured.

[0048] Depending on the dimensions of the planar object before and / or during coating, the closing means is preferably adjusted so that the full width is coated with the material exiting the nozzle outlet and at least at one end, preferably at both ends, the material directed over the surface does not exceed the maximum permitted overhang. To be adjustable during the coating process, the closing means can be coupled to an actuator that can be actuated, for example, electrically or electromagnetically. The advantage of this procedure is that as a result of changing the opening of the nozzle outlet, the excess coating material acting on the inside of the coating plant is reduced and the effort required for cleaning the coating plant is thereby reduced.

[0049] The toothed peripheral portion, preferably the toothed peripheral portion of the sprocket, is circular-cylindrical with the rotation axis at the central axis of the teeth, the rotation axis being also arranged eccentrically with respect to the nozzle outlet. The provision that the outer mold portion, e.g. of the toothed peripheral portion of the sprocket, is circular-cylindrical and the rotation axis is the central axis of the toothed peripheral portion, e.g. of the sprocket, is to be understood as meaning that the peripheral portion represents a part of a toothed circular cylinder, the axis of which corresponds to the rotation axis of the nozzle portion. In addition to this provision, if necessary, the rotation axis is eccentrically displaced with respect to the nozzle outlet of the nozzle portion. The eccentric displacement of the rotation axis with respect to the nozzle outlet of the nozzle portion is to be understood as preferably such that the rotation axis does not intersect with the nozzle outlet or, if the rotation axis intersects with the nozzle outlet, the intersection of the rotation axis with the nozzle outlet is not a symmetrical point of the nozzle outlet. In the specific case where the nozzle outlet is designed as a slot, the eccentric displacement of the rotation axis of the nozzle part relative to the nozzle outlet is preferably understood to be such that the rotation axis does not intersect the nozzle outlet or, if it does, the intersection point of the rotation axis does not halve the slot in the longitudinal direction of the slot. In a particularly advantageous manner, the eccentric rotation of the slot-shaped nozzle outlet has the effect that, in the case of a particularly preferred embodiment, the length of the slot corresponds to at least 20 times, preferably 100 times, the slot width, and that the rotation axis does not intersect the nozzle outlet or, if it does, the intersection point of the rotation axis divides the slot into two parts, the longer part being at least 110 percent, preferably at least 120 percent, of the length of the shorter part.

[0050] Despite the lack of flexibility, the embodiment of the coating plant with an eccentric axis of rotation as a result of the shape of the nozzle part in the described manner has the advantage that the object to be coated can be influenced in the desired manner in a simple manner, solely by the shape of the nozzle outlet, without the presence of a large number of potentially high-maintenance components.

[0051] In all cases where the eccentric displacement of the rotation axis is addressed as above, when properly implemented by those skilled in the art, the result is improved application and layer formation when the material present in the gas phase does not exit the nozzle with an exit direction oriented perpendicular to the surface to be coated, since the asymmetric distortion of the ejection relative to the rotating surface due to the non-perpendicular exit direction can be corrected or partially corrected by the eccentric displacement of the rotation axis.

[0052] According to a particularly preferred variant of the method, the nozzle has a longitudinal extension of the nozzle of D0, which is rotated around a rotation angle α'=α×k with respect to the conveying direction of the planar object such that sin(α')×D0 corresponds to the planar object being acted on over its entire width. The factor k is an empirically determined correction factor, which preferably assumes a value between 0.75 and 1.25. On the other hand, the described procedure consists in the concept that the nozzle has a longitudinal extension, which is oriented perpendicularly with a rotation angle of α=90 degrees with respect to the conveying direction of the strip, and preferably the nozzle opening is also in a plane parallel to the strip surface. In an idealized model, the rotation of the nozzle by the rotation angle α from the 90 degree orientation reduces the lateral extent of the coating on the planar object, and in the example of a strip, only strips with a smaller width will be completely coated over their entire lateral extent. In other words, this procedure allows the proportion of material present in the gas phase leaving the nozzle opening and distributing beyond the strip ends inside the vacuum chamber to be minimized, so that strips with smaller widths can be coated with high efficiency as well. The factor k takes into account the fact that, as experience shows, the ratios typical in real coating scenarios do not achieve the maximum coating width in the lateral extension of the object to be coated at the above-mentioned angle α=90 degrees, but instead there are deviations in individual cases that have to be empirically corrected depending on the specific circumstances. The specific embodiment of the invention thus described includes, in particular, the specific steps that empirically determined correction factors are present and used.

[0053] In a development of the method according to the invention it is further provided that the orientation of the nozzle is also changed by: Moving the axis of rotation in a direction perpendicular to the axis of rotation, or By adjusting the eccentricity of the nozzle outlet relative to the axis of rotation, such that at least at one end, but preferably at both ends, the material directed over the surface does not exceed the maximum permitted overhang. In other words, in addition to the amount of lateral extension over which the material is applied to the surface of the planar object, the position of the nozzle can also be taken into account by changing its position perpendicular to the conveying direction of the planar object, e.g. the strip.

[0054] Particularly preferably, the rotation axis is arranged relative to the nozzle in such a way that it divides the nozzle in its longitudinal extension D0 into two parts D1 and D2, where D0=D1+D2, whereby D1 / D2=Delta1 / Delta2, where Delta1 is the reduction in width of the planar object on the first side of the rotation axis and Delta2 is the reduction in width of the planar object on the second side of the rotation axis, in particular the reduction in width relative to the axis of symmetry of the conveying device used to convey the planar object. By this measure, it is ensured that not only can a change in the orientation of the rotatable nozzle be adjusted with respect to a change in the lateral extension of the planar object, which is provided symmetrically with respect to the axis of rotation of the planar object at both ends of the planar object, but also an adjustment of the orientation of the rotatable nozzle can be performed to take into account an asymmetrically performed change in the lateral extension.

[0055] It is particularly preferred that the planar object has a width that varies in the longitudinal direction. For example, the planar object can be strip metal, in particular strip steel, which has a lateral extension that varies as a function of its longitudinal position. According to a preferred method variant, such a planar object is coated, and during the coating process the orientation of the nozzle outlet relative to the surface to be coated is continuously adjusted, so that the orientation of the nozzle is adjusted in each case to the longitudinal position of the planar object currently being coated. This continuous adjustment can be based on an in situ measurement of the lateral extension during the coating process, for example by optical length detection, or on a time-dependent control of the nozzle rotation during the coating process, if there is a known dependency between the lateral extension of the planar object and its longitudinal position.

[0056] Further details, features and advantages of the subject matter of the invention emerge from the following description in conjunction with the drawings which show, by way of example, embodiments of the invention.

[0057] It goes without saying that the features mentioned above and below can be used not only in the combinations shown, but also in other combinations or alone. [Brief description of the drawings]

[0058] The drawings are as follows: [Figure 1a] FIG. 1 is a schematic diagram of a coating plant according to the present invention. [Figure 1b] FIG. 1 is a schematic diagram of a coating plant according to the present invention. [Diagram 2] FIG. 2 is a schematic diagram of a first embodiment of a rotatably mounted nozzle. [Diagram 3] FIG. 2 is a schematic diagram of a second embodiment of a rotatably mounted nozzle. [Figure 4] is the Zn coating thickness in the transverse direction of the strip. [Diagram 5] FIG. 13 is a schematic diagram of a third embodiment of a rotatably mounted nozzle. [Figure 6] FIG. 2 is a schematic diagram of a nozzle and a nozzle outlet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] FIG. 1a shows a coating plant 1 designed to coat a planar object 2 designed as strip metal 2. The coating plant 1 is designed as a strip coating plant and for this reason comprises an apparatus for conveying the strip, as known in the field of production and coating of strip metal, in particular strip steel. In the illustrated embodiment, the strip is conveyed by conveying rollers 3a, 3b. The strip is inserted into a vacuum chamber 4 and passed through the vacuum chamber in which a vacuum is present, for example at a pressure between 0.1 mbar and 20 mbar.

[0060] The strip is guided in the vacuum chamber in the conveying direction 5 and passes through a device 6 for depositing material, which in the present embodiment is designed as a jet PVD device 6 known to the skilled person in terms of its basic mode of operation. In the deposition device, the material present in the gas phase is directed to the surface of the strip metal, where it forms a coating by condensation. The device 6 has an evaporation part 7 for evaporating the material into the gas phase and a nozzle part 8 coupled to the evaporation part 7. The nozzle part 8 in particular comprises a nozzle 9 arranged in the vacuum chamber 4 and having a nozzle outlet directed to the surface of the strip to be coated in order to be able to exit the nozzle outlet and direct the material present in the gas phase towards the surface, where it can condense to form a coating. The nozzle 8 is rotatably mounted and coupled to the evaporation part 7. In the schematic illustration, the evaporation part 7 also extends partially into the vacuum chamber 4, but this is neither essential nor necessary and can be implemented as necessary by the skilled person tasked with implementing the invention. However, in order to ensure that the surface of the strip is coated, it is essential that the nozzle 9 is arranged together with the nozzle outlet in the vacuum chamber 4.

[0061] The nozzle 9 is mounted rotatably, as represented by the arrow 10. By rotation the orientation of the nozzle outlet with respect to the surface of the strip 2 to be coated can be changed, and in the illustrated embodiment a preferred embodiment has been selected according to which the axis of rotation of the nozzle 9 is oriented perpendicular to the surface to be coated and according to which the nozzle outlet located within the nozzle is shaped such that the material in the gas phase leaving the nozzle outlet leaves the nozzle in the direction of the axis of rotation, i.e. in the illustrated example with the axis of rotation oriented perpendicular to the surface to be coated the material in the gas phase acts on the surface in a direction perpendicular to the surface to be coated.

[0062] In the illustrated embodiment, the nozzle 9 is provided with a nozzle outlet in the form of a slot with a longitudinal extension D0. The nozzle is mounted on the nozzle 9 or the nozzle outlet is arranged on the nozzle 9 in such a way that when the nozzle 9 rotates about its axis of rotation, the rotational movement of the nozzle 9 takes place in a plane parallel to the strip surface and at the same time the nozzle outlet is perpendicular to the main exit direction of the material present in the gas phase. In the illustrated example, the nozzle 9 is oriented at a zero angle α to the transport direction of the strip. In the illustrated orientation, only a narrow strip of the strip is coated. In contrast, a rotation of 90 degrees about the illustrated axis of rotation results in a strip with a width, i.e. a strip with its lateral extension, which in the present representation is oriented perpendicular to the paper plane, being coated, which corresponds to the longitudinal extension D0 of the strip, with slight deviations possible due to the flow profile of the particles emerging from the nozzle outlet.

[0063] FIG. 1b is a plan view of the coating plant 1 shown in FIG. 1a. In particular, it is assumed that the nozzle outlet 11 of the nozzle 9, designed as a slot 11, is rotated at an angle α of 90 degrees to the conveying direction of the strip 2, i.e. by 90 degrees relative to the position from FIG. 1a. The longitudinal extension of the nozzle outlet 11 is greater than the transverse width of the strip. If the strip 2 has a smaller transverse width than that shown in FIG. 1b, by reducing the angle α, it can be ensured that the material that does not leave the nozzle outlet, or that leaves only a small amount of the nozzle outlet in spite of the reduced strip width, does not pass the strip end into the vacuum chamber, in particular into the region of the vacuum chamber located below the strip, and is therefore no longer available for the formation of the coating. The provision of a rotatable nozzle ensures that an efficient coating is possible even with different strip widths and even with width variations within the same strip.

[0064] Figure 2 shows a schematic diagram of one embodiment of a deposition device as a possible component of a coating plant according to the invention. The nozzle 9 shown in Figure 2 has a circular-cylindrical outer mold part, to which a sprocket 12 is clamped. A counter element 13, designed as a pinion 13, engages with the sprocket 12. The pinion 13 is coupled to a shaft 14, which is withdrawn from the vacuum chamber 4, which is coupled to a rotary drive (not shown in Figure 2) for rotating the shaft and thus the nozzle. To ensure thermal insulation of the hot nozzle 9 from the drive components, a thermal insulation means 15, designed as a ceramic ring 15, is arranged between the nozzle 9 and the sprocket 12.

[0065] Figure 3 shows a further embodiment of a deposition device as a possible component of a coating plant according to the invention. In contrast to the embodiment of Figure 2, in the embodiment of Figure 3 a helical sprocket 12 is provided, which is engaged with a counter element designed as a worm shaft 16, which is coupled to a shaft leading out of the vacuum chamber 4 through the wall 22. The shaft is coupled to a rotary drive 19. The shaft has a coolant feedthrough 20 for cooling the shaft, i.e. a line passing through the shaft and being a component of the coolant circuit. In the embodiment of Figure 2 a passive insulation of the hot nozzle 9 against the sprocket 12 is thus provided, whereas in the embodiment of Figure 3 an active cooling of the elements in contact with the nozzle is provided. The shaft is adjusted by a universal joint 17 with a lateral degree of freedom of movement. The shaft can be disengaged from and returned to engagement with the sprocket via a connecting piece 23 and a lateral drive means connected thereto. The shaft 18 is also coupled to a coolant circuit via a supply and exhaust line 21 for active cooling of the shaft 18 as a component in indirect contact with the sprocket 12 .

[0066] Figure 4 shows the layer thickness profile of a Zn coating applied once at a 90° angle and once at a 45° angle to the transport direction. It can be seen that the layer width can be adjusted by rotating the nozzle.

[0067] Fig. 5 is a schematic diagram of a third embodiment of a rotatably mounted nozzle, which is an adaptive variant of the embodiment according to Fig. 2, so that only the differences between the third embodiment and the first embodiment are shown, see also the description of Fig. 2.

[0068] Based on the schematic diagram of FIG. 5, three means are described by which it is achieved that the axis of rotation D is arranged eccentrically with respect to the nozzle outlet 11.

[0069] The first measure is that the rotation axis D is displaced eccentrically relative to the nozzle outlet 11, which means that the shape and position of the nozzle outlet as well as the rotation axis D are selected so that the rotation axis D does not intersect with the nozzle outlet at a symmetrical point on the central axis of the nozzle outlet 11 that cuts the slot-shaped nozzle outlet in half longitudinally.

[0070] The second measure consists in that in this construction embodiment, the outer mould part, which is the part of the nozzle extending axially in the area characterised by the clamp 25, in the area between the point U1 and the seat level counterclockwise from there towards U2, is made up of a peripheral part, which on the one hand has teeth and on the other hand has a peripheral part U1-U2, which in this part is circular-cylindrical, with the axis of rotation D of the nozzle part at the central axis of the teeth. On the other hand, the part adjacent to the peripheral part is not circular-cylindrical, but presents a more elliptical shape. This means that the drive by the pinion 13 is only possible in U1-U2, which has the desired effect that an eccentric movement of the nozzle outlet is produced.

[0071] The third measure is that the nozzle portion has a sliding flap 24 capable of partially closing the nozzle outlet.

[0072] It will be appreciated that the adaptations of the embodiment of FIG. 2 shown in FIG. 5 and described above may be implemented in other embodiments as well, for example the embodiment of FIG.

[0073] The effect of an eccentric axis of rotation relative to the nozzle outlet is explained using Figure 6. Figure 6 is a plan view of a nozzle 26 similar to the nozzle part 25 of Figure 5. It can be seen that the axis of rotation D' of the nozzle 26 is offset relative to the centre M of the nozzle outlet 11. The displacement is given by the distance X0. In the illustrated nozzle 26, a partial correction of the asymmetry can be achieved during a clockwise rotation, characterised by the arrow U, about the axis D'.

Claims

1. A coating plant (1) for coating a flat object (2) with a material in the gas phase, comprising: a vacuum chamber (4) for supplying the flat object (2) to be coated therethrough; a vapor deposition apparatus (6) having an evaporation part (7) for evaporating the material into the gas phase and a nozzle part (8) coupled to the evaporation part (7), wherein the nozzle part (8) is disposed within the vacuum chamber (4) and has a nozzle (9) having a nozzle outlet (11) for guiding and discharging the material present in the gas phase toward the surface (2) of the flat object (2) passing through the vacuum chamber (4) from the nozzle outlet (11) to continuously coat the object with the material that acts on the surface and condenses; the nozzle (9) is rotatably mounted to change the orientation of the nozzle outlet (11) with respect to the surface to be coated; coating plant (1).

2. The coating plant (1) according to claim 1, wherein the nozzle outlet (11) is designed as a slot.

3. The nozzle (9) is mounted such that the nozzle outlet (11) performs a rotational movement in a plane parallel to the surface to be coated when the nozzle (9) rotates, and / or the axis of rotation for rotating the nozzle (9) with respect to the surface to be coated is vertically oriented; The coating plant (1) according to claim 1 or 2, characterized by the above.

4. The nozzle (9) has a cylindrical outer mold part, and the outer mold part is toothed at the peripheral edge of its circumference or over its entire circumference, and the teeth engage with a drivable counter element (13, 16) for driving the nozzle (9) to rotate by driving the counter element (13, 16). The coating plant (1) according to claim 1 or 2, characterized by the above.

5. The nozzle (9) has a cylindrical outer mold part, and the outer mold part is fitted into a sprocket (12) with teeth on its circumferential edge or over its entire circumference, or has a sprocket with teeth on its circumferential edge or over its entire circumference. The sprocket (12) engages with a drivable counter element (13, 16) that engages with the sprocket (12) to rotate the nozzle (9) by driving the counter element (13, 16). The coating plant (1) according to claim 1 or 2, characterized in that.

6. The nozzle (9) and the sprocket (12) are designed to be thermally insulated from each other by thermal insulation means (15) disposed between the outer mold part of the nozzle (9) and the sprocket (12). The coating plant (1) according to claim 5, characterized in that.

7. The thermal insulation means (15) is an insulating ring. The coating plant (1) according to claim 6, characterized in that.

8. The insulating ring has or consists of a ceramic material. The coating plant (1) according to claim 7, characterized in that.

9. The counter element (13) is a pinion coupled to a shaft (14) drawn out from the vacuum chamber (4). The shaft (14) is coupled to a rotational drive device for rotating the shaft (14) and, as a result, rotating the nozzle (9). The coating plant (1) according to claim 4, characterized in that.

10. The counter element (16) is a worm shaft coupled to a shaft drawn out from the vacuum chamber (4). The shaft is coupled to a rotational drive device (19) for rotating the shaft and, as a result, rotating the nozzle (9). The coating plant (1) according to claim 4, characterized in that.

11. The shaft is adjusted by a connecting element designed as a universal joint (17) and having a degree of freedom of lateral movement, and the shaft is disengaged from engagement with the sprocket (12) and returned to engagement with the sprocket (12) by a connecting piece and lateral drive means coupled thereto. The coating plant (1) according to claim 10, characterized in that it is movable.

12. The rotating shaft is designed to be movable in a direction perpendicular to the rotating shaft, and / or The rotating shaft is adjusted eccentrically with respect to the nozzle outlet (11), The rotating shaft is adjustable eccentrically with respect to the nozzle outlet (11), and / or The outer mold part is circular-cylindrical having a peripheral part having a peripheral part having a rotation axis on the central axis of the teeth at least in the peripheral part having teeth, and further the rotation axis is arranged eccentrically with respect to the nozzle outlet. The coating plant (1) according to claim 3, characterized in that.

13. The nozzle part has at least one closing means for partially or completely closing the nozzle outlet (11), and is designed as a movable sliding flap for adjusting the eccentricity of the rotating shaft with respect to the nozzle outlet (11). The coating plant (1) according to claim 12, wherein the nozzle outlet (11) is designed as a slot.

14. A method for coating a flat object (2) with a material present in the gas phase by means of the coating plant (1) according to claim 1, wherein the nozzle (9) is larger than the lateral width of the flat object (2), and the orientation of the nozzle (9) with respect to the surface to be coated is The entire width is coated with the material emerging from the nozzle outlet (11), And at least at one end, the maximum overhang of the material directed beyond the surface is not exceeded. The method is changed by rotating the nozzle (9) as described above.

15. The nozzle (9) having the longitudinal extension D0 of the nozzle outlet (11) is rotated about a rotation angle alpha' = alpha × k with respect to the transport direction of the flat object so that sin(alpha') × D0 corresponds to the flat object on which it acts over its entire width, where k is an empirically determined correction factor. The method according to claim 14.

16. The orientation of the nozzle is such that at at least one end, it does not exceed the maximum overhang allowed for the material directed beyond the surface, and / or the outer mold part of the nozzle is circular-cylindrical with a peripheral part having at least teeth and having a peripheral part with a rotation axis along the central axis of the teeth, and further the rotation axis is arranged eccentrically with respect to the nozzle outlet, and the orientation of the nozzle is adjusted such that at at least one end, it does not exceed the maximum overhang allowed for the material directed beyond the surface, by moving the rotation axis in a direction perpendicular to the rotation axis, and / or by rotating the nozzle about a rotation axis eccentric with respect to the nozzle outlet, by adjusting the eccentricity of the rotation axis with respect to the nozzle outlet (11), The method according to claim 14 or 15, which is also changed thereby.

17. The rotation axis divides the longitudinal extension D0 = D1 + D2 of the nozzle outlet such that D1 / D2 = delta1 / delta2, where delta1 is the width reduction on the first side of the rotation axis and delta2 is the width reduction on the second side of the rotation axis. The method according to claim 16.

18. A flat object (2) having a longitudinally varying width is coated while successively and continuously setting the change in the orientation of the nozzle outlet (11) with respect to the surface to be coated as a function of the longitudinal position of the flat object currently being coated. The method according to claim 14 or 15.

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