Method for producing a component
The method of electroplating a sheet metal strip with a nickel-tin alloy and particles addresses the issues of flaking and cracking in vapor deposition coatings, resulting in a durable, corrosion-resistant, and wear-resistant coating suitable for high-corrosion and tribologically demanding applications.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SCHAEFFLER TECHNOLOGIES AG & CO KG
- Filing Date
- 2025-10-22
- Publication Date
- 2026-05-21
Smart Images
Figure DE2025100990_21052026_PF_FP_ABST
Abstract
Description
[0001] P241070
[0002] - 1 - Method for manufacturing a component
[0003] The invention relates to a method for manufacturing a component comprising a metallic base body with at least one coating arranged at least partially on it.
[0004] Such a process is known from DE 102017 118320 A1. In this process, a metal sheet is unwound from a roll and transported through at least one coating system, in which the metal sheet is coated on at least one side by means of a physical and / or chemical vapor deposition process. Subsequently, at least one forming process is carried out on the coated metal sheet. This results in the formation of a multitude of components by separating them from the coated metal sheet. The remaining metal sheet is wound onto another roll, with continuous transport of the metal sheet from roll to roll. The formed components, such as bipolar plates, are used in electrochemical cells.
[0005] It has been shown that the use of physical and / or chemical vapor deposition processes increases component costs and that the coatings formed tend to flake off, crack, or be damaged during the subsequent forming process.
[0006] It is therefore the object of the invention to provide an improved method for manufacturing such components.
[0007] The problem is solved by a method for manufacturing a component comprising a metallic base body with at least one coating arranged at least partially on it, in the following steps:
[0008] - Providing a sheet of metal,
[0009] - Providing at least one coating bath and at least partially passing the sheet metal strip through the at least one coating bath, wherein the sheet metal strip is electroplated, P241070
[0010] -2 - - wherein the coating is formed by optionally forming a first layer of nickel on the sheet metal strip, and by incorporating at least a second layer of a tin-nickel alloy in which particles in the form of graphite and / or molybdenum disulfide (M0S2) and / or tungsten disulfide (WS2) and / or polytetrafluoroethylene (PTFE) are incorporated,
[0011] formed directly on the sheet metal strip and / or on the optional first layer, and
[0012] - Forming a coated area of the sheet metal strip, in particular by means of a deep drawing process, whereby the component is simultaneously or subsequently cut out of the sheet metal strip.
[0013] The resulting coating is cost-effective to produce and is also ductile, making it ideally suited for forming processes and ensuring good adhesion to the sheet metal strip without flaking or cracking. Due to its excellent corrosion resistance and electrical conductivity, the coating is suitable for components subjected to particularly high levels of corrosion, especially electrical components. Furthermore, such coatings are exceptionally wear-resistant, allowing them to be used even in tribologically demanding applications.
[0014] The coating is tribologically active and exhibits high wear resistance. The embedded particles reduce friction and thus adhesive wear. These particles also provide lubrication, delaying component wear. Graphite particles are particularly preferred.
[0015] Preferably, the particle size of the particles used is in the range of 1 nm to 10 pm, particularly preferably in the range of 500 nm to 9 pm.
[0016] It has proven effective to form the tin-nickel alloy with a nickel content in the range of 20 to 35 wt.%.
[0017] Pulsed deposition of at least one second layer leads to a significant increase in the hardness of at least one second layer. P241070
[0018] To achieve a fine-grained, nanoscale deposition, the surface to be coated must have as many nucleation centers for layer growth as possible. This requires a high rate of crystal nucleation and, conversely, a low rate of crystal growth. The resulting formation of as many crystal nuclei as possible in close proximity to one another, whose crystal growth stops as soon as they reach a neighboring nucleus or crystal, creates a coating with a defined micro- or nanocrystalline structure.
[0019] In practice, this can be achieved through pulsed coating deposition. Either the electric current or the electric voltage is pulsed in the millisecond range. Each current or voltage pulse is followed by a rest phase, also in the millisecond range. This pulse profile allows for the deposition of a micro- or nanocrystalline structure, as described above, because the current peaks generated by the electric pulse significantly increase the rate of crystal nucleation.
[0020] The following parameters have proven effective for separation:
[0021] The duration of the electrical pulses is in the range of 1 to 10 ms.
[0022] The duration of the resting phases ranges from 1 to 10 ms.
[0023] The duration of the current pulses and the duration of the rest phases can be selected differently. The chosen temperature, pH value, and current density generally depend on the base electrolyte used for the deposition of at least one second layer.
[0024] This makes the coating process particularly economical and also toxicologically safe.
[0025] The sheet metal strip is preferably made of steel, in particular stainless steel. Bearing steels such as 100Cr6 and the like are especially preferred for forming the sheet metal strip. Sheet metal strips with a thickness of up to 2 mm are preferably used. P241070
[0026] - 4 - It has proven advantageous if the first layer has a thickness in the range of 1 to 3 pm. The at least one second layer is preferably formed with a thickness in the range of 2 to 6 pm. Preferably, the coating comprising the first and second layers together has a thickness in the range of 1 to 9 pm.
[0027] Preferably, the at least one second layer has a micro- or nanocrystalline structure. The second layer is considered microcrystalline, in particular, if its grain sizes are in the range of a few micrometers. The second layer is considered nanocrystalline, in particular, if its grain sizes are in the range of less than 100 nm.
[0028] In terms of cost, it has proven advantageous to unwind the sheet metal strip from a roll or coil, through which at least one coating bath is passed, and after the at least one component has been cut off, a remaining portion of the sheet metal strip is wound onto another roll.
[0029] In forming processes, particularly deep drawing, in the coated area of the sheet metal strip, embossing depths of a maximum of 3 mm are preferably produced. A pressing force of 20 tons or more can be used. This is therefore a classic deep drawing process using forming tools.
[0030] The separation of the components from the sheet metal strip preferably takes place simultaneously with the forming process, in particular the deep drawing process, or only after the forming process, in particular the deep drawing process.
[0031] The preferred component is a rolling bearing component, such as a bearing ring or a cage. Alternatively, it has proven effective to manufacture a component of an electrochemical cell, such as a half-sheet of a bipolar plate, or a component of an electrical connector. Other components that can be produced by deep drawing sheet metal can also be manufactured. P241070
[0032] - 5 - Figures 1 to 4 are intended to illustrate a method for manufacturing the component in the form of a rolling bearing ring. They show:
[0033] Figure 1 shows a rolling bearing in a three-dimensional view.
[0034] Figure 2 shows the section through the rolling bearing ring 1 according to Figure 1 ,
[0035] Figure 3 shows a further section through the rolling bearing ring 1 according to Figure 1, and Figure 4 schematically shows a suitable process sequence for the formation of the rolling bearing ring.
[0036] Figure 1 shows a rolling bearing 10 in the form of a ball bearing (shown here only as an example) in a three-dimensional view. The rolling bearing 10 has several rolling bearing components, here components 1, 1' in the form of rolling bearing rings. Furthermore, rolling elements 12 and a cage 11 are present.
[0037] Figure 2 shows an enlarged section through the rolling bearing ring 1 according to Figure 1. Visible are the metallic base body 2 and a coating 3 comprising only a second layer 3b of the tin-nickel alloy, which here contains graphite particles 4. However, several second layers 3b may also be present.
[0038] Figure 3 shows another section through the rolling bearing ring 1 according to Figure 1 in an enlarged view. The metallic base body 2 and a coating 3 comprising a first layer 3a of nickel and a second layer 3b of the tin-nickel alloy, which here contains graphite particles 4, are again visible. However, there may also be several second layers 3b.
[0039] Figure 4 schematically shows a suitable process sequence for forming the rolling bearing ring 1. A coil or roll 9 is provided, on which the stainless steel strip 2a is wound. The end of the strip 2a is optionally guided into a first treatment bath 5, and the strip is electroplated on all sides with a first layer of nickel (see Figure 3). Alternatively, a second layer 3b (see Figure 2) is formed directly on the strip 2a in a second treatment bath 5', or a second layer 3b is formed on top of the first layer 3a. The now coated strip 2a P241070
[0040] - 6 - is transported to a forming unit 6 and formed, here by means of a deep-drawing process. A punching unit 7 simultaneously or immediately afterwards separates a component 1 in the form of a rolling bearing ring from sheet metal strip 2. In at least one optional subsequent unit, the components 1 can undergo post-treatment, further processing, or measurement. The remaining portion of the previously coated sheet metal strip 2b is wound onto another roll 9' and recycled.
[0041] The formed sheet metal strip 2a therefore forms the metallic base body 2 of the component 1 in the form of the rolling bearing ring (compare figures 2 and 3), which has the coating 3.
[0042] As an alternative to a rolling bearing ring, cages for rolling bearings can also be manufactured using this method. Furthermore, sheets are also suitable for forming bipolar plates or separator plates for electrochemical cells, such as fuel cells, electrolyzers (especially for water electrolysis), or redox flow cells, as well as components for batteries, particularly for use and manufacture using the method according to the invention. Components made from formed sheets for connectors can also be manufactured without restriction using this method. P241070
[0043] - 7 - List of reference symbols
[0044] 1, r component
[0045] 2 metallic base bodies
[0046] 2a Sheet metal strip
[0047] 2b Remaining sheet metal strip
[0048] 3 coating
[0049] 3a first layer
[0050] 3b second layer
[0051] 4 particles made of graphite
[0052] 5.5' Coating bath
[0053] 6 forming unit
[0054] 7 punching unit
[0055] 8 successor unit
[0056] 9.9' roll
[0057] 10 rolling bearings
[0058] 11 Cage
[0059] 12 rolling elements
Claims
P241070 - 8 - Patent claims 1. Method for manufacturing a component (1) comprising a metallic base body (2) with at least one coating (3) arranged at least partially on it, comprising the following steps: - Providing a metal strip (2a), - Providing at least one coating bath (5, 5') and at least partially passing the sheet metal strip (2a) through the at least one coating bath (5, 5'), wherein the sheet metal strip (2a) is electroplated, - wherein the coating (3) is formed by optionally forming a first layer (3a) of nickel on the sheet strip (2a), and by forming at least a second layer (3b) of a tin-nickel alloy in which particles (4) in the form of graphite and / or molybdenum disulfide and / or tungsten disulfide and / or polytetrafluoroethylene are incorporated, is formed directly on the sheet metal strip (2a) and / or on the optional first layer (3a), and - Forming a coated area of the sheet metal strip (2a), in particular by means of a deep drawing process, wherein the component (1) is simultaneously or subsequently cut out of the sheet metal strip (2a).
2. The method according to claim 1, wherein the tin-nickel alloy is formed with a nickel content in the range of 20 to 35 wt.%.
3. Method according to one of claims 1 or 2, wherein the sheet metal strip (2a) is made of steel, in particular stainless steel.
4. Method according to any one of claims 1 to 3, wherein the first layer (3a) is formed in a layer thickness in the range of 1 to 3 pm.
5. Method according to any one of claims 1 to 4, wherein the at least one second layer (3b) is formed in a layer thickness in the range of 2 to 6 pm. P241070 - 9 - 6. Method according to any one of claims 1 to 5, wherein the sheet metal strip (2a) is unwound from a roll (9), through which at least one coating bath (5, 5') is passed and after the at least one component (1) has been cut off, a remaining residue (2b) of the sheet metal strip (2a) is wound onto a roll (9').
7. Method according to any one of claims 1 to 6, wherein component (1) is a rolling bearing component or a component of an electrochemical cell or a component of an electrical connector.
8. Method according to any one of claims 1 to 7, wherein, during forming, in particular deep drawing, embossing depths of a maximum of 3 mm are produced in the coated area of the sheet metal strip (2a).