COATING DEPOSIT METHOD
The PVD or PECVD deposition system with controlled part rotation addresses the challenge of varying column orientations in carbon coatings on complex parts, enabling uniform coating orientations and effective tribological testing.
Patent Information
- Application Number
- FR2022010459
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-10-12
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2042-10-12
AI Technical Summary
Existing PVD and PECVD carbon deposition techniques struggle to consistently control the orientation of columns in carbon coatings on parts with complex geometries, leading to varying microstructures and properties depending on the position on the part, which complicates tribological testing.
A PVD or PECVD deposition system with a mask and light configuration that allows for controlled rotation of the part relative to the target, enabling precise control over the angle of column deposition and ensuring a uniform coating orientation on complex surfaces.
This approach allows for the reproduction of column orientations found on complex parts, enabling effective tribological testing and characterization of carbon coatings under controlled conditions, thereby improving the understanding and optimization of coating performance.
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Abstract
Description
Title of the invention: COATING DEPOSIT METHOD Technical field
[0001] The invention relates to the field of producing diamond-type carbon coatings with regular and progressive growth or graphite coatings on technical parts by PVD type deposition, physical vapor deposition in English or PECVD type, Plasma-Enhanced Chemical Vapor Deposition in English or plasma-assisted chemical vapor deposition in French. Prior art
[0002] It is known to produce PVD or PECVD carbon deposits and, in the context of the development of diamond-like carbon coatings (DLC diamond-like carbon in English) for example, there is a problem of different growth of the deposits depending on the geometries of the parts of the parts concerned, particularly in the context of parts with complex geometry. Depending on the position on the same part, the deposit may have a different microstructure, in particular the orientation of the columns of the deposited material may vary. This different orientation can lead to different properties. Thus, on the same part, the coating may have a different structure and thus different properties depending on its position on the part.
[0003] [Fig. 1] represents for example a deposition by PVD process which results in the columnar growth of a coating 2 oriented at an angle 0 between a substrate 1 and the columns of the coating 2.
[0004] In the case of tribological tests on coated parts with complex geometries, for example gears, it is extremely difficult to characterize the properties of the deposit directly on the final parts, especially on small surfaces and / or non-planar shapes of these parts because the orientation of the columns producing the coating is not controlled.
[0005] It is therefore necessary to develop a deposition technique which can reproduce the different orientations of the columns forming a coating on a part of chosen geometry so as to carry out classic tribological tests according to these orientations.
[0006] There are tribological tests that allow the rolling-sliding conditions to be reproduced at a point of contact between two parts and the samples used for this purpose are discs, balls, rollers. On the other hand, for a gear such as shown diagrammatically in [Fig.2], at the level of contact between two gear teeth 1a, 1b such that for example tooth 1a is the tooth of a driving pinion and tooth 1b the tooth of a driven pinion, columns 12a, 12b of coatings 11a, 11b are in opposition and the rolling-sliding kinetics between the surfaces is complex. In such a case, there is currently no tribological test to sort the coating solutions other than carrying out tests on the teeth. It is therefore necessary to find a way to carry out tests according to the different possible inclinations for the columns of the coatings. Technical problem
[0007] Known solutions do not allow the deposition angle to be varied on samples and thus the influence of this angle on the effectiveness of the deposition on parts in contact and in motion to be characterized. Statement of the invention
[0008] In view of the prior art, the present disclosure proposes to produce, on samples representative of the future surfaces in contact, a coating representative of that present on these surfaces and, to do this, to adapt the device and the spraying method.
[0009] To do this, the present disclosure firstly proposes a PVD or PECVD deposition device comprising an enclosure in which there is a part to be coated mounted movably on a support, and a target of a material of a coating to be evaporated and deposited on the part, which comprises a mask provided with a light facing the part to be coated and fixed relative to the target, said mask being arranged between the target and the part, said movably mounted part being positioned behind the mask relative to the target so that a movement of the part behind the light progressively scrolls an area to be coated on the surface of the part behind the light. This makes it possible to produce on the part an area coated with a columnar deposit of said material as the part scrolls under the light.
[0010] The light preferably defines an opening of a dimension adapted to channel a vapor deposition beam onto said area to be coated behind the light, a width of the light in a direction of movement, in particular rotation of the part being defined between 1 and 7 cm.
[0011] A first axis perpendicular to said area to be coated of said surface forms an angle greater than 0° and less than 90° relative to a second axis perpendicular to a plane of the target and directed towards the part.
[0012] The first axis perpendicular to said area to be coated advantageously forms an angle greater than 10° and less than 80° relative to the second axis. Preferably, said angle can be defined between 20° and 70°.
[0013] According to a first embodiment, the part is rotated around said first axis.
[0014] According to a second embodiment, the part is rotated around a third axis perpendicular to the first axis and to the second axis.
[0015] The part may have rotational symmetry about a rotary axis, and said movement of the part relative to the support is a rotation about the rotary axis of the part. The light for its part is parallel to the surface to be coated and close to this surface, for example at a distance of a few millimeters, for example less than 15 mm, or even less than 7 mm or even 3 mm.
[0016] The mask may comprise a screen plate arranged on at least one edge of the light and parallel, at more or less 20°, to said second axis and in particular inclined at more or less 20° to said second axis. This screen plate is positioned and oriented to guide the beam coming from the target onto the surface.
[0017] The mask is advantageously made of steel.
[0018] The present disclosure further relates to a deposition method using the device described above and comprising a. - a positioning of said part to be coated, mounted mobile relative to the support, behind the mask relative to the target, with the light of the mask located opposite an area of the surface of the part to be coated, b. - rotation of the part behind said mask according to a movement of the part behind the light adapted to progressively scroll behind the light said area of the surface of the part to be coated, c. - spraying coating material towards the light and said area so as to produce on the part an area coated with a columnar deposit of said material.
[0019] The method may be such that, a first axis perpendicular to said area to be coated under said light making an angle α with a second axis perpendicular to a plane of the target, the method comprises, before said spraying, an adjustment of said angle α, as a function of an inclination of said columnar deposit to be produced. Brief description of the drawings
[0020] Other characteristics, details and advantages of the invention will appear on reading the detailed description below of non-limiting exemplary embodiments, and on analyzing the appended drawings, in which:
[0021] [Fig-1] shows a microscope view of a coating deposited on a surface by a PVD process;
[0022] [Fig.2] shows a schematic side view of gear teeth provided with a coating obtained by a PVD process;
[0023] [Fig.3A] shows a schematic top view of a first embodiment of the device of the present disclosure;
[0024] [Fig.3B] shows a schematic side sectional view of the device of [Fig.3A];
[0025] [Fig.3C] shows a schematic side view of the device of [Fig.3A];
[0026] [Fig.4A] shows a schematic top view of a second embodiment of the device of this disclosure;
[0027] [Fig.4B] shows a schematic side view of the embodiment of [Fig.4A];
[0028] [Fig.5A] shows a schematic top view of a third embodiment of the device of this disclosure;
[0029] [Fig.5B] shows a schematic side view of the embodiment of [Fig.5A];
[0030] [Fig.6] shows a schematic top view of a variant of the embodiment of [Fig.5A]; Description of the embodiments
[0031] The following drawings and description contain elements which may not only serve to better understand the present invention, but also contribute to its definition, where appropriate.
[0032] As described above, [Fig. 1] represents a coating 2 formed in columns at an angle 0 relative to the surface of a substrate 1. This angle 0 will depend on the direction in which the coating particles are projected onto the surface of the part.
[0033] Depending on the position on the same part, the deposit may have a different microstructure and in particular the orientations of the columns may vary due to tip and shadow effects. This variable orientation may lead to different properties of the coating depending on its position on the part. Thus, the same deposit, on the same part, may have a different structure and thus different properties depending on its position.
[0034] It is also extremely difficult to characterize the properties of the deposit directly on a final part of complex geometry, especially when the surface concerned is small and / or non-planar in shape.
[0035] In the case of [Fig.2] for example we see that the orientation of the columns 12a, 12b of PVD coatings 11a, 11b in a contact zone between two teeth 10a, 10b of a gear will depend on the local curvature of these teeth when they are subjected to the bombardment of particles intended to produce the coating.
[0036] It is therefore desirable to be able to reproduce these orientations in order to better understand the behavior of the coatings according to the inclinations of the columns of said coatings and to be able to carry out tribological tests making it possible to reproduce the rolling-sliding conditions at a point of contact according to the inclinations of the coating columns that one wishes to test. To carry out tribological tests, the samples used are discs, balls, rollers. The device of the The purpose of this disclosure is to produce coatings whose inclinations of the material columns are controlled and known.
[0037] The aim of the invention is thus to produce, on surfaces of such samples, to be brought into contact, a coating representative of that present on areas of complex parts such as gear teeth in order to study their behavior (and with the possibility of controlling the angle of inclination of the columns, in order to be able to test the influence of this inclination).
[0038] The PVD or PECVD deposition device of the present disclosure comprises, according to the embodiment of [Fig.3A], an enclosure 25 in which there is a part 22 to be coated, here an annular part one face of which must be coated, a target 20 which will provide the material to be evaporated to produce the coating and a mask 21. The mask 21 arranged between the target and the part 22 is provided with a light or opening 23. The part is mounted movably on a support 24, here a rotating support while the mask is stationary relative to the target.
[0039] The light is parallel to the surface to be coated and close to this surface, for example at a distance of a few millimeters, for example less than 15 mm, or even less than 7 mm or even 3 mm.
[0040] In this embodiment, the part 22 to be coated is an annular washer, the mask 21 is a disc and the light 23 is constituted here by a notch along an angular sector of the mask.
[0041] Still according to this embodiment, an axis X normal to the area to be coated is identical to an axis A of rotation of the part 22 on its support 24. The axis X makes an angle α with an axis Y normal to the surface of the target and the light 23 uncovers a small sector of a face of the annular part, the fixed disk of the mask being arranged above the rotating part. The light thus forms on the part an area to be coated with an axis normal to X of reduced dimension in the circumferential direction of the part 22. The light thus allows the particles to be deposited with a common orientation on the exposed part of the part, which makes it possible to coat the face of the part moving under said light 23 with a homogeneous deposit provided with columns of constant inclination θ such that θ=90°-α, α being the angle between the axis Y normal to the target and the axis X normal to the area to be coated of the part.
[0042] [Fig. 3C] seen from the side of the light 23 makes it possible to better distinguish the positioning of the light 23 relative to the part 22 and the inclination a of the axis of rotation of the part relative to the normal to the plane of the target. The coating is deposited through the light 23 on the surface of the part 22 progressively during the rotation of the latter, for example at a speed of 1 rpm to 50 rpm depending on the application.
[0043] The dimensions of the light 23 are such that it defines an opening of a dimension suitable for channeling a vapor deposition beam onto a portion of the part behind the light and orienting the deposition according to parallel columns.
[0044] To define the dimensions of the light, it is desirable: a. that the opening is not too small, because otherwise, due to tip effects, there is a risk of everything being deposited on the mask, without the material reaching the part, b. That the opening is not too large either, to remain sufficiently angularly directional,
[0045] In particular, a width of the light in a direction of rotation of the part defined between 1 and 7 cm makes it possible to obtain a great homogeneity of the orientation of the columns.
[0046] The angle a between the first axis X perpendicular to the area to be coated under the light and the second axis Y normal to the target and directed towards the part is greater than 0° and less than 90° and preferably greater than 10° and less than 80° to obtain columns respectively making an angle with the surface of the part between 80° and 10°. In a particular embodiment, the angle a is chosen so that the columns make an angle of 40° to 60° with the surface of the part.
[0047] Figures 4A and 4B correspond to a second embodiment for which the mask 21a is made so as to mask a part of a spherical part 22a. In this example, the part is mobile in rotation around its axis of rotation A which is coincident with an axis Z called third axis perpendicular to the second axis Y normal to the plane of the target, the mask is conical with axis of revolution along the axis Z and comprises a light 23a made by an opening on a sector of the cone. Alternatively, the mask could be a spherical cap, for example a shell in the shape of a half-sphere, with a localized light corresponding to an angular sector, a circular light or a rectangular light. However, the conical mask as shown has the advantage of allowing the mask and the light to be very close to the part at the level of the area to be coated, which is favorable for the deposition.
[0048] As in the first embodiment, the light is offset by an angle α relative to the Y axis, that is to say that its angular position around the Z axis is offset relative to the Y axis by an angle α, so that the deposition under the light is done with a given inclination on the part. In the present case, the deposition is also carried out on the lower part of the spherical part not covered by the mask without this being a problem, the active part for the tests being the strip 26 located between two parallels at the level of the light.
[0049] In this embodiment, the mask is always fixed and the part 22a is rotated around the third axis Z perpendicular to the first axis X and to the second Y axis. An annular band of homogeneous deposition whose columns of material are inclined at an angle dependent on the angle a is produced by rotating the spherical part 22a under the mask and spraying material onto the unmasked area 26 under the light 23a.
[0050] Figures 5A and 5B correspond to an embodiment for which the part 22b to be covered is cylindrical (it is a roller) and mounted on a support 24 provided with an axis of rotation A along an axis Z perpendicular to an axis Y normal to the target 20 and for which the coating must be deposited on the cylindrical external wall of the part.
[0051] In this embodiment, the mask 21b is in the form of a cylindrical ring fixed relative to the target 20, surrounding said external wall and provided with a light 23b in the form of a slot parallel to the axis of rotation Z.
[0052] In this embodiment, the inclination according to the angle 0 of the columns is obtained by an angular offset a between the position of the window (angular position around the Z axis), and the Y axis perpendicular to the target 20.
[0053] In the example of [Fig.6], the mask comprises on at least one side of the light a screen plate 23c which will help to direct the particles and force unidirectional growth of the columns constituting the coating. This screen plate can in the case of the embodiment of [Fig.3A] be produced by a raised edge of a notch formed in the disc constituting the mask 21, raising this edge allowing the window 23b to be opened.
[0054] The mask is advantageously made of steel, which makes it a lightweight mask, easy to implement, able to be sandblasted for cleaning and inexpensive.
[0055] The parts to be coated can be metal, ceramic or polymer parts such as plastics.
Claims
Claims
1. PVD or PECVD deposition device comprising an enclosure (25), a part (22) to be coated mounted movably in the enclosure on a support (24), and a target (20) of a material of a coating to be evaporated and deposited on the part, characterized in that it comprises a mask (21) provided with an aperture (23) facing the part (22) to be coated and fixed relative to the target (20), said mask being arranged between the target and the part, said movably mounted part being positioned behind the mask relative to the target in such a way that a movement of the part behind the aperture progressively scrolls an area to be coated of the surface of the part behind the aperture for which a first axis (X) perpendicular to said area to be coated of said surface forms an angle (a) greater than 0° and less than 90° relative to a second axis (Y) perpendicular to a plane of the target and directed towards the part,characterized in that the mask comprises a screen plate (23c) arranged on at least one edge of the light and parallel, at more or less 20°, to said second axis (Y).,
2. PVD or PECVD deposition device according to claim 1 for which the light (23) defines an opening of a dimension adapted to channel a vapor deposition beam onto said area to be coated behind the light, a width of the light in a direction of movement of the part being defined between 1 and 7 cm.
3. PVD or PECVD deposition device according to claim 1 or 2 for which the first axis (X) perpendicular to said zone to be coated forms an angle (a) greater than 10° and less than 80° relative to the second axis (Y) and preferably between 20° and 70°.
4. PVD or PECVD deposition device according to any one of the preceding claims for which the part is rotated around said first axis (X).
5. PVD or PECVD deposition device according to any one of the preceding claims, for which the part is rotated around a third axis (Z) perpendicular to the first axis (X) and to the second axis (Y).
6. PVD or PECVD deposition device according to any one of the preceding claims for which the part has rotational symmetry around a rotary axis (A), and for which said
7.
8.
9. movement of the part relative to the support is a rotation around the rotary axis (A) of the part. PVD or PECVD deposition device according to any one of the preceding claims, for which the mask is made of steel. Deposition method using the device according to any one of the preceding claims comprising: a. - a positioning of said part to be coated, mounted movably relative to the support, behind the mask relative to the target, with the light (23) of the mask located opposite an area of the surface of the part (22) to be coated, b. - rotation of the part behind said mask according to a movement of the part behind the light adapted to progressively scroll behind the light said area of the surface of the part to be coated, c. - evaporation of coating material in the direction of the light and of said area so as to produce on the part an area coated with a columnar deposit of said material, said material being guided on said area of the surface of the part to be coated by a screen plate arranged on at least one edge of the light and parallel to more or less 20° of said second axis (Y). Deposition method according to claim 8, for which, a first axis (X) perpendicular to said area to be coated under said light making an angle α with a second axis (Y) perpendicular to a plane of the target, the method comprises, before said evaporation, an adjustment of said angle α, as a function of an inclination of said columnar deposit to be carried out.