Improved method and apparatus for atmospheric plasma jet coating deposition on substrates

Abstract

The invention relates to a method for plasma coating an object comprising an object profile, comprising the following steps: a. Manufacturing an exchangeable shield (2) comprising a jet inlet (22), a nozzle outlet (24) and a side wall (21) extending from the jet inlet to the nozzle outlet, the nozzle outlet comprising an edge (25) substantially consistent with at least a portion of the object profile; b, detachably attaching a replaceable shielding piece to a jet outlet of the plasma jet generator; c, placing the object at the outlet of the nozzle, so that the outline of the object is tightly matched with the edge of the outlet of the nozzle, and the gap between the outlet of the nozzle and the object is minimized; d. Coating the object with a low-temperature oxygen-free plasma by providing a plasma jet in the shield via a plasma jet generator and spraying a coating precursor in the plasma jet in the shield, thereby generating an operating pressure, at an operating pressure above atmospheric pressure, preferably at most 10%, thus, the object is plasma-coated in an oxygen depleted plasma region.

Description

[0001] This application is a divisional application of the invention patent application with application number 201980041732.6 (PCT / EP2019 / 066647), application date June 24, 2019, and invention name “Improved method and device for atmospheric pressure plasma jet coating deposition on a substrate”. Technical Field

[0002] The present invention relates to the technical field of plasma deposition. Therefore, the present invention may relate to IPCH05h1 / 24 and / or IPCB01J19 / 08. Background Art

[0003] Coating by plasma deposition offers many advantages over other coating techniques, in particular over wet techniques in which the coating is applied by subjecting the object to a liquid containing the coating substance. For example, plasma coating allows very thin coatings, which allows the coated object to have all types of shapes, with little loss of coating substance, etc.

[0004] Plasma coating techniques can generally be divided into vacuum techniques and atmospheric techniques. The present invention relates to atmospheric plasma coating, in which the pressure of the plasma is close to atmospheric pressure. In practice, the plasma pressure may be slightly different from atmospheric pressure, for example slightly overpressured. Atmospheric plasma coating techniques have major advantages over vacuum plasma coating techniques, since no vacuum chamber is required and the coating process can be easily performed in-line.

[0005] Many plasma coating methods are disclosed in patent documents EP0217399A2, US3914573A, US2017 / 095929A1 and EP1875785A1. These documents relate to a specific type of plasma spray gun that heats the plasma to 1000°C or higher and sprays the plasma onto a substrate at high speed. Methods such as those disclosed in US3914573A can generally be used to coat metal objects such as steel with material particles whose melting temperature is much higher than the plasma temperature. High plasma temperatures are required to soften the material particles to enhance coating of the substrate.

[0006] However, the present invention relates to different types of atmospheric plasma coating methods and apparatus thereof, which allow molecular substances to be coated on all types of substrates, including metal and non-metal substrates, and in particular also plastic and / or glass substances with melting and / or flow temperatures far below 1000°C, sometimes even below 200°C, 150°C, 100°C or even lower. Obviously, the dedicated equipment and processes of plasma spray guns disclosed in EP0217399A2, US3914573A, US2017 / 095929A1 and EP1875785A1 cannot be used. Plasma coating technology at low temperatures, usually below 200°C plasma temperature, is required.

[0007] JP2008 / 130503A discloses an apparatus including an atmospheric pressure plasma jet generating device and a processing chamber. The plasma jet can be inserted into the processing chamber. The processing chamber includes an upper part and a lower part made of resin and separated from each other by a small gap, which causes gas to flow out of the processing chamber through the small gap, whereby the apparatus is configured to prevent ambient air from being contained in the processing chamber by overpressure.

[0008] This document discloses solving the problem of providing an atmospheric pressure plasma jet device capable of extending the plasma mushroom to effectively reform the surface regardless of the surface shape of the material.

[0009] However, the device according to this document is not suitable for coating deposition. This document describes in particular cleaning and hydrophilicity improvement as possible uses.

[0010] Furthermore, the device according to this document is not suitable for in-line processing of continuous substrates. This document particularly describes an opening area adjustment device (or a closing member) for loading and unloading the processing object. This document also describes that the size of the processing object is approximately equal to the opening surface of the upper part of the processing chamber. Therefore, this document provides a batch processing chamber.

[0011] Furthermore, the device according to this document is not suitable for easy cleaning, long-term maintenance and / or in-line treatment of a plurality of irregular surfaces.

[0012] JP2007 / 323812A discloses an atmospheric pressure plasma device, which includes a first reaction space and a mixed gas container including a mixed gas region. The device is configured to insert a primary plasma jet from the first reaction space into the mixed gas region, and insert a mixed gas containing a reaction gas into the mixed gas region to collide with the primary plasma.

[0013] The device according to this document is not suitable for in-line plasma deposition on continuous substrates with irregular surfaces. In addition, the device is not suitable for easy cleaning and / or long-term maintenance.

[0014] The present invention aims to solve at least some of the problems mentioned above.It is therefore an object to allow all types of substrates to be atmospherically plasma coated in-line at low temperatures to obtain a uniform coating. Summary of the invention

[0015] In a first aspect, the present invention provides a method of depositing a coating by means of an atmospheric pressure plasma jet according to claim 1 .

[0016] In a second aspect, the present invention provides a kit according to claim 13 for an atmospheric pressure plasma jet generator.

[0017] In a third aspect, the present invention provides an apparatus for depositing a coating by means of an atmospheric pressure plasma jet according to claim 16 .

[0018] In another aspect, the present invention provides a method for depositing a coating by an atmospheric pressure plasma jet, the method comprising the steps of:

[0019] - providing an atmospheric pressure plasma jet generator (1) comprising a jet outlet (12);

[0020] - providing a shield (2) comprising a jet inlet (22), a nozzle outlet (24) and a side wall (21) extending from the jet inlet to the nozzle outlet;

[0021] - removably attaching the shield to the plasma jet generator and thereby communicatively coupling the jet inlet and the jet outlet;

[0022] - providing a plasma jet in the shield by means of a plasma jet generator and injecting a coating precursor into the plasma jet of the shield, thereby generating an overpressure in the shield relative to the environment; and

[0023] - The surface of the substrate and the nozzle outlet are moved relative to each other, thereby depositing a coating on said surface.

[0024] The nozzle outlet of the shield can be placed close to the surface of the substrate to be treated, and a large influx of ambient air can be prevented by an overpressure in the shield. During coating deposition, the shield may degrade, for example due to degradation of the inner wall of the shield by the plasma jet and / or deposition of the coating on the inner wall of the shield. In addition, and more importantly, when substrates of different sizes and / or shapes are used, a single nozzle may not produce satisfactory results for each substrate. The present invention allows the shield to be replaced according to the application. For online coating deposition on larger flat surfaces, a shield with a larger flat nozzle outlet can be used. For online coating deposition on non-flat surfaces, a shield with a particularly suitable non-flat nozzle can be used. For the processing of limited irregular samples, the sample can remain stationary and the jet can move, whereby the nozzle outlet can include a sufficiently small size to allow the surface of the sample to be closely followed. The invention allows in-line plasma coating of all types of objects with low-temperature oxygen-free plasma at an operating pressure slightly above atmospheric pressure, preferably up to 10%, by providing a plasma jet in a shield via a plasma jet generator and spraying a coating precursor in the plasma jet in the shield, thereby generating said operating pressure. Due to the conformity of the nozzle outlet edge to the contour of the object, the overpressure combined with the small gap between the nozzle outlet edge and the object surface allows the object surface to be subjected to an oxygen-depleted plasma zone, which in turn leads to better results of the coating, in particular in terms of uniformity and stability, including better adhesion of the coating to the surface and less degradation over time. In addition, the presence of an oxygen-depleted plasma zone allows the use of a large number of precursor molecules, which otherwise could not be used due to their reactivity with oxygen.

[0025] It should also be noted that in the present invention the plasma temperature is preferably kept low, preferably below 200°C, more preferably below 180°C, more preferably below 160°C, more preferably below 140°C, more preferably below 130°C, more preferably below 120°C, more preferably below 110°C, more preferably below 100°C, more preferably below 90°C, more preferably below 80°C, more preferably below 70°C, more preferably below 60°C, more preferably below 50°C.

[0026] Other advantages, features and examples of the present invention are disclosed in the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 1 a and 1 b show perspective views of an embodiment of the device according to the invention.

[0028] Figure 2a, Figure 2b, Figure 2c, Figure 2d and Figure 3 A perspective view showing an embodiment of a visor according to the invention is shown.

[0029] Figure 4 A perspective view of an embodiment of a visor and an adapter according to the present invention is shown.

[0030] 5a and 5b show a longitudinal view and a side view, respectively, of an embodiment of a shield according to the present invention.

[0031] Figure 6 A side view of an alternative embodiment of a visor according to the present invention is shown.

[0032] Figure 7 A sectional view of a device according to the invention with a shield is shown, which is particularly preferably used for plasma coating of powders.

[0033] Figure 8 A sectional view of a device according to the invention with a shield is shown, which is particularly preferably used for plasma coating of fibers.

[0034] Fig. 9 A perspective view of a shield according to the invention is shown, the edges of which are specially made to conform to an axially symmetrical object. DETAILED DESCRIPTION

[0035] The present invention relates to an apparatus and method for depositing a coating by an atmospheric pressure plasma jet. The present invention also relates to a kit. The present invention has been summarized in the above corresponding sections. The present invention is described in detail below, and preferred embodiments are discussed and the present invention is illustrated by embodiments.

[0036] Unless defined otherwise, all terms (including technical and scientific terms) used in disclosing the present invention have the meaning commonly understood by one of ordinary skill in the art to which the present invention belongs. By way of further guidance, term definitions are included to better understand the teachings of the present invention.

[0037] As used herein, the following terms have the following meanings:

[0038] As used herein, "a", "an", and "the" refer to the singular and the plural, unless the context clearly indicates otherwise. By way of example, "a compartment" refers to one or more than one compartment.

[0039] When "about" is used herein with respect to measurable values ​​such as parameters, amounts, durations, etc., it is meant to include variations of + / 20% or less, preferably + / 10% or less, more preferably + / 5% or less, even more preferably + / 1% or less, and still more preferably + / 0.1% or less of the specified value, within which such variations are suitable for implementation in the disclosed invention. However, it should be understood that the value referred to by the modifier "about" itself is also specifically disclosed.

[0040] As used herein, “comprise,” “comprising,” and “comprises,” and “comprised of” are synonymous with “include,” “including,” “includes,” or “contain,” “containing,” and are inclusive or open-ended terms that specify the presence of the following (e.g., components), and do not exclude or preclude the presence of additional, unrecited components, features, elements, members, steps that are known or disclosed in the art.

[0041] The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints.

[0042] In a first aspect, the present invention provides a method for depositing a coating by an atmospheric pressure plasma jet, comprising several steps. A plasma jet generator comprising a jet outlet is provided. A shield is manufactured, the edge of which is consistent with the contour of the object to be treated. The shield comprises a jet inlet, a nozzle outlet and a side wall extending from the jet inlet to the nozzle outlet. The shield can be detachably attached to the plasma jet generator, thereby connecting the jet inlet and the jet outlet in a communicative manner. The plasma jet can be provided to the shield by the plasma jet generator. The coating precursor can be injected into the plasma jet of the shield. Therefore, an overpressure relative to the environment can be generated in the shield. The surface of the substrate can move relative to the nozzle outlet, and thus the coating can be deposited on the surface.

[0043] In a second aspect, the present invention provides a kit. The kit can be configured for use with an atmospheric pressure plasma jet generator including a jet outlet. The nozzle kit can include an adapter and a plurality of replaceable shields. Each shield includes a jet inlet, a nozzle outlet, and a sidewall extending from the jet inlet to the nozzle outlet. The adapter can be configured to removably attach one of the shields to the plasma jet generator and thereby communicatively couple the jet outlet and the jet inlet.

[0044] In a third aspect, the present invention provides an apparatus for depositing a coating by an atmospheric pressure plasma jet. The apparatus comprises a plasma jet generator, the plasma jet generator comprising a jet outlet. The apparatus further comprises an adapter and a replaceable shield. The shield comprises a jet inlet, a nozzle outlet, and a sidewall extending from the jet inlet to the nozzle outlet. The adapter is configured to removably attach the shield to the plasma jet generator and thereby communicatively couple the jet outlet and the jet inlet.

[0045] The nozzle set according to the second aspect can be used in the device according to the third aspect and / or the method according to the first aspect. The method according to the first aspect can be performed by the device according to the third aspect. A person skilled in the art will understand that the three aspects of the invention are therefore interrelated. Therefore, each feature disclosed above or below in this document can be applicable to each aspect of the invention, even if it has been disclosed in conjunction with a specific aspect.

[0046] As used herein, "atmospheric pressure" means that the pressure approximates or approximately matches the pressure of the surrounding environment. This term distinguishes the plasma technology of the present invention from low-pressure and high-pressure plasma technologies that require a reaction vessel to maintain a significant pressure difference with the environment. Therefore, it will be understood by those skilled in the art of plasma technology that "atmospheric pressure" as used herein should not be interpreted as the pressure unit "standard atmosphere (atm)" defined as 101 325Pa.

[0047] As used herein, "communicatively coupled" refers to mass flow, i.e., fluid, gas and / or plasma flow. Thus, the communicatively coupled jet outlet of the plasma jet generator and the jet inlet of the shield are configured for the plasma jet exiting the jet outlet to enter the shield through the jet inlet.

[0048] As used herein, "plasma jet" refers to a plasma jet and / or the afterglow of a plasma jet. For example, a coating precursor injected into a "plasma jet" within a shield may refer to a coating precursor injected into a plasma jet and / or the afterglow of a plasma jet within a shield.

[0049] The method of the present invention comprises the following steps:

[0050] a. manufacturing a replaceable shield (2), the shield (2) comprising a jet inlet (22), a nozzle outlet (24) and a side wall (21) extending from the jet inlet to the nozzle outlet, wherein the nozzle outlet comprises an edge (25) substantially conforming to at least a portion of the contour of the object;

[0051] b. The replaceable shield can be removably attached to the jet outlet of the plasma jet generator;

[0052] c. placing the object at the nozzle outlet so that the object contour closely matches the nozzle outlet edge, thereby minimizing the gap between the nozzle outlet and the object;

[0053] d. coating the object with a low-temperature oxygen-free plasma at an operating pressure higher than atmospheric pressure, preferably at most 10%, by providing a plasma jet in the shield via a plasma jet generator and spraying a coating precursor in the plasma jet in the shield, thereby generating the operating pressure.

[0054] The object is thereby plasma coated in an oxygen-depleted plasma region.

[0055] In step a, the replaceable field area is in particular manufactured to have an edge that is consistent with at least a part of the object contour. Therefore, if different types of objects are to be coated, different shields can be manufactured, each shield having a consistent edge for the corresponding type of object. Therefore, the method can also be used for plasma coating of multiple types of objects, each type of object comprising a different object contour, wherein step a is performed for each type of object, thereby manufacturing a plurality of replaceable shields, each shield comprising a nozzle outlet having a nozzle outlet edge that is substantially consistent with at least a part of the object contour of the corresponding object. In a preferred embodiment, 3D printing technology is used to manufacture the shield, which allows very complex edges to be manufactured in a relatively fast and reliable manner.

[0056] The method is particularly concerned with low temperature plasmas. Therefore, the plasma temperature is preferably below 120°C, more preferably below 70°C.

[0057] The kit of the present invention comprises a plurality of replaceable shielding members (2), each of the shielding members comprising a jet inlet (22), a nozzle outlet (24) and a side wall (21) extending from the jet inlet to the nozzle outlet, wherein the nozzle outlet of each shielding member comprises a nozzle outlet edge substantially consistent with at least a portion of the object contour of the object, preferably, each shielding member comprises a nozzle outlet, the nozzle outlet edge of the nozzle outlet substantially consistent with a corresponding portion of the object contour or with at least a portion of the corresponding object contour of multiple types of objects.

[0058] In order to allow easy removal of the first shield and easy attachment of the second shield, preferably, the shield is detachably attached to the jet outlet by means of an adapter (3), which is configured to detachably attach the shield to the plasma jet generator and thereby communicatively connect the jet outlet of the plasma jet generator and the jet inlet of the shield.

[0059] During step d, the object may be moved relative to the nozzle outlet and the edge, for example to perform in-line coating. Thus, the edge is preferably kept at a distance of at least 0.1 mm and at most 5 mm, preferably at least 0.2 mm and at most 2 mm, more preferably at least 0.5 mm and at most 1 mm from the surface of the substrate.

[0060] In a preferred embodiment, the object profile is substantially the same along the longitudinal direction and said relative movement comprises a relative translation along said longitudinal direction.This is particularly true for plate-like or sheet-like objects which may be non-planar, ie have a non-straight cross section perpendicular to the longitudinal direction.

[0061] In a preferred embodiment, the edge is a first edge that circumferentially conforms to the contour of the object, and wherein the shield comprises a second edge that is an object inlet edge that circumferentially conforms to the contour of the object, and wherein the relative movement comprises a movement of the object in the longitudinal direction from the object inlet edge through the processing chamber within the shield to the first edge. This is particularly useful if the object is a fiber having a contour comprising a substantially circular cross section that is the same in the longitudinal direction, preferably whereby a method according to claim 9 is used, wherein the first edge and the second edge comprise circular openings having a diameter that conforms to the cross section of the fiber, thereby allowing the fiber to pass through the openings of the first edge and the second edge. This is also particularly useful if the object is a powder that is blown in the longitudinal direction, which forms a powder beam having a contour comprising a substantially circular cross section that has a diameter that is the same in the longitudinal direction or that varies in the longitudinal direction, preferably whereby a method according to claim 9 is used, wherein the first edge and the second edge comprise respective circular openings having respective diameters that conform to the cross section of the powder beam at the location of the first edge and the second edge, respectively, thereby allowing the powder to pass through the openings of the first edge and the second edge.

[0062] In another preferred embodiment, the object profile is substantially axially symmetrical about a central axis, and the relative movement comprises a relative rotation about the central axis. Thus, by rotating the object or the shield, or both, for example 360° or integer multiples of 360° about the central axis in multiple coating passes, the surface of the object can be treated in a fast and reliable manner.

[0063] The kit preferably also includes a plasma jet generator to which each of the plurality of shields can be attached.The kit may include one plasma jet generator or more than one (eg, two, three, four or more) plasma jet generators.

[0064] The device of the present invention comprises:

[0065] - a plasma jet generator (1) comprising a jet outlet (12); and

[0066] a nozzle comprising an adapter (3) and a replaceable shield (2), the shield comprising a jet inlet (22), a nozzle outlet (24) and a side wall (21) extending from the jet inlet to the nozzle outlet,

[0067] The adapter is configured to detachably attach the shield to the plasma jet generator, and thereby communicatively connect the jet outlet and the jet inlet.

[0068] The nozzle outlet of the shield can be placed close to the surface of the substrate to be treated, and a large influx of ambient air can be prevented by overpressure in the shield. During coating deposition, the shield may be degraded and / or contaminated, for example, due to degradation of the inner wall of the shield by the plasma jet and / or deposition of the coating on the inner wall of the shield. In addition, when substrates of different sizes and / or shapes are used, a single nozzle may not produce satisfactory results for each substrate. The present invention allows the shield to be replaced according to the application. For online coating deposition on larger flat surfaces, shields with larger flat nozzle outlets and larger precursor output can be used. For online coating deposition on non-flat surfaces, shields with particularly suitable non-flat nozzle outlets can be used. For limited processing of irregular samples, the sample can remain stationary and the plasma jet generator can be moved, whereby the nozzle outlet can include a sufficiently small size to allow the surface of the irregular sample to be closely followed. When the first coating precursor used for the first coating deposition on the first substrate is not desired in the second coating deposition on the second substrate, the nozzle can be replaced to avoid contamination by the first coating precursor during the second coating deposition.

[0069] In a preferred embodiment, the shield comprises a flange attached to the side wall at the jet inlet. The adapter may comprise a retaining wall comprising an opening of a size and shape suitable for retaining the flange. The adapter and the plasma jet generator may comprise complementary attachment means configured to attach the adapter to the plasma jet generator. The adapter may be configured to press the flange of the shield against the plasma jet generator at a certain position by means of the retaining wall, thereby connecting the jet outlet and the jet inlet in a communicative manner. Preferably, the flange comprises a flat surface surrounding the jet inlet. Preferably, the flange is adapted to be pressed against the plasma jet generator by the adapter to avoid a large amount of ambient air flowing into the shield through the jet inlet. Thus, the flange comprises the dual purpose of avoiding a large amount of ambient air flowing into the shield through the jet inlet and avoiding the shield being attached to the jet generator through the adapter. The shield comprises a length direction, along which the jet inlet and the nozzle outlet are spatially separated. Preferably, the flange is substantially perpendicular to the length direction. Preferably, the planar surface of the flange is substantially perpendicular to the length direction.

[0070] Preferably, the shield is monolithic. The shield may be manufactured by injection molding. The shield may be manufactured by 3D printing. Preferably, the shield comprises an insulating material, more preferably a plastic. The nozzle outlet of the shield comprises an edge. The nozzle outlet of the shield may comprise a flat edge, i.e. the nozzle outlet is flat. The nozzle outlet of the shield may comprise a non-flat edge, i.e. the nozzle outlet is non-flat. This allows in-line coating of non-flat surfaces, thereby maintaining a small distance between each portion of the edge and the surface.

[0071] The coating precursor may be injected into the plasma jet of the shield. The jet outlet of the plasma jet generator may include a plurality of outlet compartments. The plasma jet generator may be configured to provide a plasma jet from a first compartment and a coating precursor from a second compartment. The jet outlet may include two concentric cylindrical walls defining an inner compartment for providing a coating precursor and an outer compartment for providing a plasma jet. The jet outlet may include a rectangular outlet divided into three compartments by two inner walls and defining a middle compartment for providing a coating precursor and two outer compartments for providing a plasma jet.

[0072] In a preferred embodiment, the side wall of the shield comprises at least one precursor inlet, preferably at least two precursor inlets, such as two, three, four or more precursor inlets. The precursor inlet may comprise a tubular hollow body comprising a first outer end coupled in communication with the interior of the shield, and a second outer end for coupling in communication with a precursor source. The tubular body may be cylindrical. The tubular body may comprise one or more bends. The coating precursor may be injected into the plasma jet of the shield through the at least one precursor inlet.

[0073] In a preferred embodiment, the jet outlet of the plasma jet generator comprises an opening, and the jet inlet of the shield comprises an opening, wherein the opening of the jet inlet is larger than the opening of the jet outlet. This is advantageous because the expansion leads to a decrease in velocity and an increase in pressure, thereby contributing to the generation of an overpressure inside the shield relative to the environment. This is further advantageous because the sharp expansion may cause turbulence and / or recirculation and thus cause mixing of components present in the corresponding parts of the shield. Preferably, the shield includes a length between the jet inlet and the nozzle outlet, and the at least one precursor inlet is connected to the interior of the shield in a distance of the jet inlet equal to at most 50% of the length, preferably at most 40% of the length, more preferably at most 30% of the length. This is advantageous because the inflow of the precursor occurs in an area where recirculation also occurs. This is further advantageous because the inflow of the precursor occurs in a direction substantially non-parallel to, preferably substantially perpendicular to, the direction of the plasma jet inflow at the jet inlet, preferably substantially parallel to the length direction, thereby further enhancing turbulence.

[0074] In a preferred embodiment, the side wall of the shield comprises a tapered portion. The tapered portion may expand the cross-section of the shield from the jet inlet towards the jet outlet, for example for depositing a coating on a larger substantially flat surface. The tapered portion may contract the cross-section of the shield from the jet inlet towards the jet outlet, for example for concentrating the coating deposition on a narrow point, thereby optionally producing a small nozzle outlet so as to be able to closely follow an irregular surface by movement of the nozzle outlet. Preferably, the tapered portion is adapted for the nozzle outlet to comprise an opening that is smaller than the jet inlet. Preferably, the tapered portion extends over at least 20% of the length of the shield.

[0075] In a preferred embodiment, the nozzle comprises a homogenizing device. Preferably, the shield comprises said homogenizing device, preferably on the inner side. The homogenizing device may comprise a flow disturbance element. The flow disturbance element may comprise a plurality of inclined surfaces. The flow disturbance element may comprise a plurality of layers, each of said layers comprising a plurality of inclined surfaces. The flow disturbance element may comprise a surface having an angle of at least 20° and at most 70° with the length direction of the shield.

[0076] In a preferred embodiment, the nozzle is adapted for cooling. Preferably, the side wall of the shield comprises a channel for the passage of a cooling fluid. Preferably, the channel is located at a distance of at most 60%, more preferably at most 50%, even more preferably at most 45% of the shield length from the nozzle outlet.

[0077] In a preferred embodiment, the device may comprise a conveying device for in-line treatment of a flat or non-flat surface of a continuous substrate, wherein the device is configured to keep each portion of the edge of the nozzle outlet at a distance of at least 0.1 mm and at most 5 mm, preferably at least 0.2 mm and at most 2 mm, more preferably at least 0.5 mm and at most 1 mm from the surface of the substrate. The method may comprise the step of relatively moving the surface of the substrate and the nozzle outlet, wherein each portion of the edge is kept at a distance of at least 0.1 mm and at most 5 mm, preferably at least 0.2 mm and at most 2 mm, more preferably at least 0.5 mm and at most 1 mm from the surface of the substrate, and thereby depositing a coating on the surface. The gap of said size between the edge of the nozzle outlet and the surface of the substrate is particularly suitable for preventing the inflow of ambient air through a slight overpressure in the shield, while allowing sufficient outflow of gas from the shield.

[0078] In a preferred embodiment, the plasma jet generator is configured to generate the plasma jet by a dielectric barrier discharge or a corona discharge.Preferably, the plasma jet generator comprises an AC power source.

[0079] The present invention is further described by the following non-limiting examples, which further illustrate the present invention and are not intended to, and should not be construed to, limit the scope of the present invention.

[0080] Example

[0081] Example 1: First device

[0082] At least part of a first embodiment of a device according to the invention is shown in Figure 1a. The device comprises an atmospheric pressure plasma jet generator (1), and a nozzle comprising an adapter (3) and a shield (2).

[0083] The plasma jet generator (1) comprises a body (11) having a cylindrical outer end. The cylindrical outer end comprises a side wall (14) and an end wall (13) substantially perpendicular to the side wall, wherein a jet outlet (12) is arranged. The cylindrical outer end comprises a diameter (d5). The jet outlet (12) comprises a diameter (d1). The plasma jet generator (1) comprises two cylindrical walls defining two compartments in the jet outlet (12): an inner compartment for providing a coating precursor and an outer compartment for providing a plasma jet and / or afterglow. The plasma jet generator can be constructed exemplarily according to claims 1 to 8 of EP1844635B1 and the corresponding parts of the specification.

[0084] The shield (2) includes a jet inlet (22), a nozzle outlet (24) and side walls (21a, 21b) extending from the jet inlet (22) to the nozzle outlet (24). The shield includes a length direction, and the jet inlet (22) and the nozzle outlet (24) are spaced apart along the length direction. The shield (2) includes a flange (26) at the jet inlet, which is attached to the side wall (21a) at the edge (23) of the jet inlet (22) and surrounds the jet inlet (22). The jet inlet includes a diameter (d2). The nozzle outlet includes a diameter (d6). The shield includes a tapered portion (21a), which is arranged to be within a distance from the jet inlet equal to at most 50% of the length of the shield in the length direction. The tapered portion (21a) narrows the shield from the jet inlet toward the nozzle outlet, whereby the nozzle outlet diameter (d6) is smaller than the jet inlet diameter (d2). The jet inlet diameter (d2) is greater than the jet outlet diameter (d3), thereby achieving the advantageous results described in the detailed description. The nozzle outlet comprises a flat edge (25), ie the edge of the nozzle outlet lies substantially in a plane. Preferably, the plane is substantially perpendicular to the length direction.

[0085] The adapter (3) comprises a retaining wall (31) comprising a circular opening (32) comprising a diameter (d3) substantially equal to or slightly greater than the jet inlet diameter (d2) plus twice the thickness of the side wall (21a). Thus, the opening (32) comprises a size and shape configured to retain the flange (26) of the shield (2) and in particular to press the flange (26) against the end wall (13) of the plasma jet generator (1). The retaining wall comprises a diameter (d4) substantially equal to the outer end diameter (d5). The adapter also comprises two curved side wall portions (33) for positioning on the side wall (14) of the outer end of the plasma jet generator, and two arms (34), the side wall portions (33) comprising attachment means (35) for attaching the adapter to the plasma jet generator, thereby pressing the flange (26) against the end wall (13) while maintaining the jet outlet (12) and the jet inlet (22) communicatively coupled. The attachment means may comprise a hole for attaching an elastic tensioning mechanism.

[0086] Example 2: Device

[0087] At least part of a second embodiment of a device according to the invention is shown in Figure 1b. The device comprises an atmospheric pressure plasma jet generator (1'), and a nozzle with an adapter (3') and a shield (2').

[0088] The plasma jet generator (1') comprises a main body (11') comprising a cuboid outer end. The cuboid outer end comprises a side wall (14') and an end wall (13') substantially perpendicular to the side wall, and a jet outlet (12') is arranged therein. The cuboid outer end comprises a height (h5) and a width (l5). The jet outlet (12') comprises a height (h1) and a width (l1). The plasma jet generator (1') comprises two inner walls defining the following three compartments in the jet outlet (12'): an inner compartment for providing a coating precursor, and two outer compartments for providing a plasma jet and / or afterglow. The plasma jet generator can be constructed exemplarily according to claims 9 to 15 of EP1844635B1 and the corresponding parts of the specification.

[0089] The shield (2') comprises a jet inlet (22'), a nozzle outlet (24') and a side wall (21') extending from the jet inlet (22') to the nozzle outlet (24'). The shield comprises a length direction, along which the jet inlet (22') and the nozzle outlet (24') are spaced apart. The side wall comprises a uniform rectangular cross-section substantially perpendicular to the length direction. The shield (2') comprises a flange (26') at the jet inlet, the flange (26') being attached to the side wall (21') at an edge (23') of the jet inlet (22') and surrounding the jet inlet (22'). The jet inlet and the nozzle outlet comprise a height (h2) and a width (l2). The nozzle outlet (24') comprises a flat edge (25'), i.e., the edge of the nozzle outlet is substantially located in a plane. Preferably, the plane is substantially perpendicular to the length direction.

[0090] The adapter (3') comprises a retaining wall (31') comprising a rectangular opening (32') comprising a height (h3) and a width (l3) substantially equal to or slightly greater than the jet inlet height (h2) and width (l2) plus twice the thickness of the side wall (21'). Thus, the opening (32') comprises a size and shape configured to retain the flange (26') of the shield (2') and in particular to press the flange (26') against the end wall (13') of the plasma jet generator (1'). The retaining wall comprises a height (h4) and a width (l4) substantially equal to the height (h5) and width (l5) of the outer end, respectively. The adapter also comprises two side wall portions (33') for positioning on the side wall (14') of the outer end of the plasma jet generator and two arms (34'), the side wall portions (33') comprising attachment means (35') for attaching the adapter to the plasma jet generator, thereby pressing the flange (26') against the end wall (13') while keeping the jet outlet (12') and the jet inlet (22') communicatively coupled. The attachment means may comprise a hole for attaching an elastic tensioning mechanism.

[0091] Example 3: Visor shape

[0092] In this example, reference is made to Figures 2a, 2b, 2c and 2d. The specific features disclosed in this example may relate to the shields of Examples 1 and 2 above. The shield includes a jet inlet (22", 22"') and a nozzle outlet (24", 24"'). In addition, the shield includes a length direction, and the jet inlet and the nozzle outlet are spatially separated along the length direction. The shield also includes a side wall (21a", 21b", 21"') extending from the jet inlet to the nozzle outlet. The shield includes a length along the length direction, that is, the distance separating the jet inlet and the nozzle outlet. The jet inlet includes a substantially flat edge (23") substantially perpendicular to the length direction. The shield also includes a flange (26", 26"') located at the jet inlet and attached to the side wall, which surrounds the jet inlet. The side wall of the shield may include a uniform cross-section perpendicular to the length direction (Figures 2c and 2d). The side wall of the shield may alternatively include a tapered portion (21a") and a portion (21b") having a uniform cross-section perpendicular to the length direction. The side wall of the shield may include a cross-section perpendicular to the length direction, which is circular (Figures 2a and 2b), elliptical, rectangular (Figures 2c and 2d), square, triangular, pentagonal, hexagonal, diamond, octagonal, star-shaped, cross-shaped, etc. Preferably, the side wall of the shield includes a cross-section perpendicular to the length direction, which cross-section includes a shape suitable for the jet outlet and also includes one or more dimensions that are larger than the corresponding dimensions of the jet outlet. Most preferably, the shape is circular or rectangular. The shield also includes a nozzle outlet edge (25", 25"') at the nozzle outlet (24", 24"'). The nozzle outlet edge can be flat (Figures 2a and 2b). The nozzle outlet edge can be located in a plane perpendicular to the length direction. The nozzle outlet edge can also be non-flat (Figures 2c and 2d). Thus, the nozzle outlet edge may comprise two portions, which are at different distances from the flange. Thus, the nozzle outlet edge may comprise a portion having a curvature in the length direction.

[0093] Example 4: Additional shield features

[0094] Reference Figure 3 The shield may include at least one, preferably at least two, precursor inlets (27). The precursor inlet is preferably connected to the shield through the side wall, more preferably within a distance of at most 50% of the shield length from the jet inlet. The precursor inlet may be formed by a tapered portion (21a) of the side wall ( Figure 3 ), or alternatively connected by a straight portion of the side wall (ie, the portion parallel to the length direction).

[0095] refer to Figure 3 and Figure 4In order to protrude from the precursor inlet (27, 27"") and / or include a shield that includes a tapered portion (21"") that widens from the jet inlet (22"") toward the nozzle outlet (24""), the adapter may include a hinge (36") and a locking mechanism (37") for realizing a flange (26") around the shield so that the flange (26") is pressed against the end wall of the plasma jet generator by a retaining wall (31") of the adapter.

[0096] In Figures 5a, 5b and Figure 6 , a view along the length direction, a side view perpendicular to the length direction, and another side view perpendicular to the length direction of an embodiment of a shield according to the present invention are respectively shown. The side wall of the shield includes a channel for the passage of a cooling fluid. The channel includes an inlet (29a), an outlet (29c), and a spiral portion (29b) extending from the channel inlet (29a) to the channel outlet (29c) in the side wall. The channel can be set within a range of a distance from the jet inlet equal to at most 50% of the shield length (Figures 5a and 5b). The channel can alternatively and preferably be set within a range of a distance from the nozzle outlet equal to at most 50% of the shield length (Figures 5a and 5b). Figure 6 ). The shield also includes a plurality of flow disturbance elements (28) in multiple layers. The layers are spaced apart in the length direction. Each element may include a surface that is at an angle of at least 20° and at most 70°, preferably at least 30° and at most 60° to the length direction, thereby being configured to substantially turn the flow direction so that components of the plasma and / or afterglow and / or gas can be mixed within the shield. The multiple layers may be arranged within a range of a distance from the nozzle outlet equal to at most 50% of the shield length (Figures 5a and 5b). The multiple layers may alternatively and preferably be arranged within a distance from the jet inlet equal to at most 50% of the shield length (Figures 5a and 5b). Figure 6 ). Thus, the cooling mechanism and the homogenizing device may be arranged in the same part of the shield, or in different parts of the shield.

[0097] Example 5: Powder coating

[0098] Figure 7 A sectional view of a device according to the invention with a shield is shown, which is particularly preferably used for plasma coating of powders.

[0099] An inert gas may be provided at a predetermined flow rate at the inlet of the guide system (40). The powder (41) may be added, for example, by a venturi injector (42). The resulting powder beam is then directed to a coating device (44) having a first plasma jet generator (45a) and a second plasma jet generator (45b), to which an inert gas and an aerosol (46a, 46b) containing a precursor are provided. A shield (47) is detachably attached to the jet outlets of the two plasma jet generators (45a, 45b) by two adapters (48a, 48b), so that the jet inlet (49a, 49b) of the shield is connected to the jet outlets of the plasma jet generators. The powder beam flows through the plasma in a longitudinal direction (50) from an inlet edge of the object circumferentially aligned with the powder beam, and is continuously exposed to the plasma for a certain length (51), thereby allowing individual powder particles to be coated. The beam leaves the shield through an object exit edge that is circumferentially aligned with the powder beam and is then collected in a collector system (52), such as a cyclone, to extract the coating powder (54) from the inert gas (53). The coating powder can be returned to the inlet (40) for further coating cycles.

[0100] Example 6: Fiber coating

[0101] Figure 8 A sectional view of a device according to the invention with a shield is shown, which is particularly preferably used for plasma coating of optical fibers.

[0102] This setup is similar to Example 5. A fiber (55) is pulled through a coating device (44) having a first plasma jet generator (45a) and a second plasma jet generator (45b), to which an inert gas and an aerosol (46a, 46b) containing a precursor are supplied. A shield (47) is removably attached to the jet outlets of the two plasma jet generators (45a, 45b) by two adapters (48a, 48b), so that the jet inlet (49a, 49b) of the shield is connected to the jet outlets of the plasma jet generators. The fiber passes through the plasma in a longitudinal direction (56) from an object inlet edge (57) that is circumferentially consistent with the fiber, and is continuously exposed to the plasma for a certain length (51). The fiber leaves the shield through an object outlet edge (58) that is circumferentially consistent with the fiber. The coating powder can be returned to the inlet (57) for further coating cycles.

[0103] Example 7: Spin coating

[0104] Fig. 9 A perspective view of a shield according to the invention is shown, the edges of which are specially made to conform to an axially symmetrical object.

[0105] The shield (60) is particularly manufactured to handle an axisymmetric object (61) comprising a radial profile (62). The shield (60) thus comprises a jet inlet (63) and a nozzle outlet, the nozzle outlet comprising an edge (64) conforming to the radial profile (62). During subjecting the surface of the object to the plasma, the object is rotated (65) about its central axis (66). The shield may have a flange close to the jet inlet for easy and detachable attachment to the jet outlet of a plasma jet generator, for example as shown in the previous examples or as Figures 1A to 5B Note that Fig. 9 In the embodiment of the present invention, the surface of the object may be slightly indented into the edge (64) to minimize the gap between the object and the shield.

Claims

1. A method for plasma coating an object including an object contour, comprising the following steps: a. manufacturing a replaceable shield (2), the shield (2) comprising a jet inlet (22), a nozzle outlet (24) and a side wall (21) extending from the jet inlet to the nozzle outlet, wherein the nozzle outlet comprises an edge (25) substantially conforming to at least a portion of the contour of the object; b. The replaceable shield can be detachably attached to the jet outlet of the plasma jet generator; c. placing the object at the nozzle outlet so that the contour of the object closely matches the nozzle outlet edge, thereby minimizing the gap between the nozzle outlet and the object; d. by providing a plasma jet in the shield via the plasma jet generator and spraying a coating precursor in the plasma jet in the shield, thereby generating an operating pressure which is higher than the atmospheric pressure, preferably at most 10% higher, at which the object is coated with a low-temperature oxygen-free plasma, The object is thereby plasma coated in an oxygen-depleted plasma region, wherein in step d, the plasma is coated at a temperature below 120° C., wherein the shield comprises an insulating material.

2. The method according to claim 1, characterized in that The shield is detachably attached to the jet outlet via an adapter (3), the adapter being configured to detachably attach the shield to the plasma jet generator, and wherein the jet outlet of the plasma jet generator is communicatively coupled to the jet inlet of the shield.

3. The method according to claim 1, characterized in that In order to plasma coat multiple types of objects, each type of object includes a different object contour, wherein step a is performed for each type of object, thereby manufacturing a plurality of replaceable shields, each shield including a nozzle outlet having a nozzle outlet edge that substantially corresponds to at least a portion of the object contour of the corresponding object.

4. The method according to claim 1, characterized in that The side wall of the shield comprises at least one precursor inlet (27), and wherein the coating precursor is injected into the plasma jet of the shield through the at least one precursor inlet.

5. The method according to claim 1, characterized in that Step d comprises the following steps: e. moving the surface of the object and the nozzle outlet relative to each other to deposit a coating on the surface, Preferably, during step e, of moving the surface of the object and the nozzle outlet relative to each other to deposit a coating on the surface, the edge is maintained at a distance of at least 0.1 mm and at most 5 mm, preferably at least 0.2 mm and at most 2 mm, more preferably at least 0.5 mm and at most 1 mm from the surface of the substrate, and thereby depositing a coating on the surface.

6. The method according to claim 5, characterized in that The object contour is substantially the same along a longitudinal direction, and the relative movement comprises a relative translation along the longitudinal direction, the edge is a first edge that is circumferentially consistent with the object contour, and wherein the shield comprises a second edge, the second edge being an object entrance edge that is circumferentially consistent with the object contour, and wherein the relative movement comprises movement of the object in the longitudinal direction from the object entrance edge through the processing chamber within the shield to the first edge.

7. The method according to claim 5, characterized in that The object profile is substantially axisymmetric about a central axis, and the relative motion comprises a relative rotation about the central axis.

8. The method according to claim 1, characterized in that - said object is a fiber having a profile comprising a substantially circular cross section which is the same in the longitudinal direction, preferably whereby the method according to claim 6 is used, wherein said first edge and said second edge comprise a circular opening having a diameter corresponding to the cross section of said fiber, thereby allowing said fiber to pass through said openings of said first edge and said second edge; or - the object is a powder blown in the longitudinal direction, thereby forming a powder beam having a profile comprising a substantially circular cross-section, the cross-section having a diameter that is the same in the longitudinal direction or that varies in the longitudinal direction, preferably thereby using the method as claimed in claim 6, wherein the first edge and the second edge comprise respective circular openings having respective diameters corresponding to the cross-section of the powder beam at the location of the first edge and the second edge, respectively, thereby allowing the powder to pass through the openings of the first edge and the second edge.

9. The method according to claim 1, characterized in that The shielding member is manufactured using 3D printing technology.

10. The method according to claim 1, characterized in that The visor comprises, and is preferably made of, a polymer material.

11. A kit for performing the method according to any one of claims 1 to 10, comprising a plurality of replaceable shields (2), each of the shields comprising a jet inlet (22), a nozzle outlet (24) and a side wall (21) extending from the jet inlet to the nozzle outlet, wherein: The nozzle outlet of each of the shielding members includes a nozzle outlet edge that is substantially consistent with at least a portion of the object contour of the object. Preferably, each of the shielding members includes a nozzle outlet, and the nozzle outlet edge of the nozzle outlet is substantially consistent with a corresponding portion of the object contour or with at least a portion of the corresponding object contour of multiple types of objects, wherein the shielding member includes an insulating material.

12. The kit according to claim 11, wherein: The kit comprises an adapter (3) configured to removably attach at least one of the shielding members, preferably each of the shielding members, to a plasma jet generator, thereby communicatively connecting a jet outlet of the plasma jet generator and a jet inlet of the shielding member attached to the plasma jet generator, the kit also comprising a plasma jet generator, each of the plurality of shielding members being attachable to the plasma jet generator.

13. An apparatus for depositing a coating by means of an atmospheric pressure plasma jet, the apparatus comprising: A plasma jet generator (1), comprising a jet outlet (12); as well as A nozzle comprising an adapter (3) and a replaceable shield (2), the shield comprising a jet inlet (22), a nozzle outlet (24) and a side wall (21) extending from the jet inlet to the nozzle outlet, wherein the nozzle outlet of each shield comprises a nozzle outlet edge that substantially conforms to at least a portion of an object contour of the object, wherein the adapter is configured to detachably attach the shield to the plasma jet generator and thereby communicatively couple the jet outlet and the jet inlet, The shielding member comprises insulating material.

14. The device according to claim 13, characterized in that The shield comprises a flange (26) attached to the side wall (21) at the jet inlet (22), and wherein the adapter comprises a retaining wall (31) including an opening (32) of a size and shape suitable for retaining the flange.

15. The device according to claim 13, characterized in that The shield is integral.

16. The device according to claim 13, characterized in that The visor comprises, and is preferably made of, a polymer material.

17. The device according to claim 13, characterized in that The nozzle outlet of the shield comprises a non-planar edge (25'"), wherein: - said side wall comprises a tapered portion (21a), - the side wall of the shield comprises at least one precursor inlet (27), and / or the jet outlet (24) comprises an opening, and wherein the jet inlet (22) comprises an opening larger than the opening of the jet outlet.

18. The device according to claim 13, characterized in that The nozzle comprises a homogenizing device (28), and preferably the shield comprises a flow disturbing element.

19. The device according to claim 13, characterized in that The nozzles are adapted for cooling (29a, 29b, 29c), preferably the side walls of the shield comprise channels for the passage of a cooling fluid.

20. The device according to claim 13, characterized in that The device comprises a conveying device for in-line processing of flat or non-flat surfaces of a continuous substrate, wherein the nozzle outlet (24) of the shield comprises an edge (25), and wherein the device is configured to maintain the edge at a distance of at least 0.1 mm and at most 5 mm, preferably at least 0.2 mm and at most 2 mm, more preferably at least 0.5 mm and at most 1 mm from the surface of the substrate.

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