EP1587968A2

EP1587968A2 - Coating method

Info

Publication number: EP1587968A2
Application number: EP04705386A
Authority: EP
Inventors: Andreas Fath; Martin Surm; Armin Waidele
Original assignee: Hansgrohe SE
Current assignee: Hansgrohe SE
Priority date: 2003-01-27
Filing date: 2004-01-27
Publication date: 2005-10-26
Anticipated expiration: 2024-01-27
Also published as: WO2004067804A2; WO2004067804A3; ATE497031T1; EP1587968B1; DE502004012147D1; US20060210813A1

Abstract

The invention relates to a method for coating objects, particularly sanitary ware such as plumbing fixtures, shower fittings and the like, during which at least one layer made of copper, nickel or of a copper-nickel alloy is firstly applied to the object. The object itself and/or at least the uppermost applied layer are/is then subjected to a mechanical surface treatment, and at least one nickel-tungsten layer and/or at least one palladium-nickel layer are/is applied to the object or the surface-treated layer. The surface treatment preferably ensues by brushing and/or blasting. This enables objects to be provided with a specific appearance, particularly a high-grade steel-like appearance.

Description

description

Beschichtunqsverfahren

The invention relates to a method for coating objects, in particular sanitary objects such as sanitary fittings, sanitary showers and the like, and to the objects which can be produced using this method.

A wide variety of objects have been coated with inorganic or organic substances for a variety of reasons for a long time. The reason for these coatings are on the one hand functional requirements, e.g. B. corrosion protection, or for other decorative requirements, eg. B. the visual appearance. Objects are often coated for both functional and decorative reasons.

Coatings are of particular importance for all types of sanitary objects, in particular for sanitary fittings. On the one hand, these must meet functional requirements, ie they must be highly corrosion-resistant, easy to clean, scratch-resistant, to name just a few of these requirements. On the other hand, they have to meet high decorative requirements, that is to say, for example, glossy or matt surfaces with a certain “appearance” have to be provided A well-known example is the application of chrome, whereby shiny surfaces with high corrosion resistance are obtained. The problems encountered when coating objects, in particular in sanitary engineering, arise to a particular extent in the case of objects made of metal or with metal surfaces, but also in the case of objects made of plastic or with plastic surfaces. On the one hand, certain metals can either not be used at all or can only be used in coated form due to their properties or for reasons of cost. On the other hand, in contrast to metals, plastics have a very low heat capacity. Mechanical surface treatment of metallized plastic parts is therefore only possible to a limited extent, since otherwise the (particularly galvanically applied) metal layers can detach from the plastic surfaces again due to the heat input resulting from the mechanical treatment into the plastic part. This can lead to high reject rates in industrial production.

Furthermore, certain “optics” should be adjustable on all base bodies. This applies particularly to the so-called “stainless steel optics”. In such an embodiment, the coated metal part or the metal-coated plastic part should also have the visual impression of a stainless steel surface, in particular a brushed stainless steel surface, if this part is not made of stainless steel or is coated with stainless steel. In many cases, sanitary fittings are made in particular of brass, die-cast zinc or other metals and then coated, in particular with metals. Sanitary fittings, sanitary showers or at least the parts belonging to such fittings such as connecting parts, ptosettes or connecting parts are also often made of plastic and then coated (with metals). All these parts should then have the "stainless steel look" mentioned.

There are already various approaches in the prior art for providing surfaces of certain optics on plastic objects. The desired surface is often imitated by a painting process. The paint contains, for example, aluminum pigments, which are colored accordingly by the addition of dyes. The surfaces obtained are often unsatisfactory in terms of their optical appearance and functional properties such as scratch resistance.

In another procedure, a copper layer applied to the plastic part is brushed and then nickel-plated. This nickel layer is then provided with a transparent protective lacquer. The disadvantage of this method is that if the paint layer is damaged, the corrosion protection is also lost.

As an alternative to the painting processes mentioned, stainless steel or a layer similar to stainless steel can also be applied to matt chrome-plated plastic parts in a vacuum (PVD process). The resulting surface then has the color of stainless steel, but not the typical surface structure of brushed stainless steel. Another disadvantage is that the application of metal layers in the PVD process is very expensive.

The invention therefore has the object, inter alia, of providing a coating method for objects, in particular sanitary objects, in which a specific optical appearance of the coated object can be achieved in a targeted manner. In particular, the invention is intended to provide a method for providing a coated object with the optical appearance of brushed stainless steel. The coated object with this look should meet the functional requirements placed on it, particularly in sanitary engineering. This object is achieved by the method with the features of claim 1 and by the subject matter with the features of claim 12. Preferred embodiments of this method or subject matter are shown in the dependent claims 2 to 11 and 13 to 41. The wording of all claims is hereby incorporated by reference into the content of this description.

According to the invention, the method mentioned at the outset is characterized in that at least one layer of copper, nickel or a copper-nickel alloy is optionally applied to the object. The object and / or at least the uppermost layer applied is mechanically surface-treated. Then at least one nickel-tungsten layer and / or at least one palladium-nickel layer is applied over the surface-treated layer.

The surface treatment mentioned above is preferably carried out by brushing and / or blasting. It is further preferred if the surface treatment is carried out at least partially by brushing in any case. Polishing can also be mentioned as the preferred surface treatment.

Here, brushes are understood to mean a mechanical surface treatment in which the surface is processed with a brush or a processing agent of equivalent effect, having sufficient strength and hardness, with partial removal of the metal layer. Through this process, the characteristic structures such as grooves, depressions and the like are worked into the surface, as are characteristic of such processing with brushes known to the person skilled in the art. The brushed metal layer in question may of course not be completely removed. As is known, the person skilled in the art understands blasting to mean a mechanical surface treatment in which, for example, (quartz) sand or glass beads as blasting media (diameter usually 0.5 to 1.5 mm) are hurled onto the corresponding surface with the aid of compressed air blowers. This creates the surface structures that are characteristic of blasting.

As already mentioned, brushing and blasting can be used alternatively or in combination in the invention. At least a part of the surface to be treated is preferably brushed, in which case the parts of the surface that are difficult to reach and process with the brush / brush disc are then blasted.

According to the invention, the applied layers of copper, nickel or copper-nickel alloys are preferably made comparatively “soft” so that a simple mechanical surface treatment, in particular by brushing, is made possible. Copper layers, in particular galvanically deposited copper layers, are usually sufficiently soft In this context, the so-called (known to the person skilled in the art) sulfamate nickel, which is deposited as a soft matt nickel from a sulfamate-based nickel bath (without organic additives), is to be emphasized as nickel layers.

The method according to the invention is preferably designed in such a way that a copper layer is first applied to the object and then a nickel layer. This nickel layer is then mechanically surface-treated, preferably brushed and / or blasted. According to the invention, the nickel layers are, in particular, so-called sulfamate nickel layers, ie soft matt nickel layers as are known to the person skilled in the art.

According to the invention, it is further preferred if at least one further layer of copper, nickel or a copper-nickel alloy is applied to the surface-treated object / base body or to the surface-treated layer before the nickel-tungsten layer or palladium-nickel layer is applied is applied. Depending on the metal used, such further layers can increase the corrosion resistance or produce special optical effects in the finally obtained coated article. The further layer is preferably a nickel layer, in particular a so-called sulfamate nickel layer.

As can already be seen in part from the previous statements, the layers of the metals mentioned are preferably at least partially according to the invention by electrodeposition, ie. H. obtained by deposition from an electrolyte under current flow. All metal layers applied to the object are preferably electrodeposited. A plastic object which is not conductive per se is made conductive by methods known to the person skilled in the art. For example, the plastic surface is activated with palladium and metallized with nickel. A so-called Vomickel layer can optionally be applied to the thin nickel layer thus obtained by deposition under current flow. The basic structure thus obtained is then further treated according to the invention.

In a further development, it is preferred in the process according to the invention if at least one siloxane or polysilo- or polysilo- xan top layer is applied. As is known, siloxanes / polysiloxanes are obtained from organosilanes, for example by thermal treatment. The so-called sol-gel method, which leads to the polysiloxane layers also known in the literature under the keyword “sol-gel coatings”, is particularly suitable for this purpose. Such a top layer effects an additional sealing of the surface and can change its physical and chemical properties ( (eg with respect to abrasion resistance, corrosion resistance, water repellant effect for liquids, etc.) Although pigmented polysiloxane layers are possible in accordance with the invention, the cover layer will generally be a transparent polysiloxane layer.

It goes without saying that the object to be coated can be subjected to a customary pretreatment before the method according to the invention is carried out. Such pretreatment steps are known to the person skilled in the art. The usual chemical and / or physical methods are to be mentioned here, which can be cited under the keywords anodic degreasing, cathodic degreasing, hot degreasing, ultrasound degreasing and the like. Such known pretreatment and activation steps can of course also be used between the individual process steps, for example before the application of further metal layers.

The object according to the invention, ie preferably the sanitary object according to the invention such as a sanitary fitting, sanitary shower and the like, according to the invention consists of a basic body. At least one layer of copper, nickel or a copper-nickel alloy is optionally located on this base body. The base body and / or optionally the top layer is mechanically surface-treated. At least one is then located above the surface-treated base body or the uppermost (surface-treated) layer Nickel-tungsten layer and / or at least one palladium-nickel layer. Depending on the version, the base body is made of metal or has metal surfaces (no stainless steel) or it is made of plastic or has plastic surfaces.

The base body or the uppermost layer on which the nickel-tungsten layer and / or palladium-nickel layer is located is in particular brushed and / or blasted. With regard to the surface structures thus defined, express reference is made to the above statements and reference. Polishing is also possible.

In a further development, there is preferably at least one further layer of copper, nickel or a copper-nickel alloy between the surface-treated base body or the surface-treated layer and the nickel-tungsten layer or palladium-nickel layer in the subject matter of the invention.

In accordance with the previous explanations, preferred objects according to the invention can accordingly be characterized by the following structure:

1. Object with a base body made of metal or a base body with metallic surfaces (no stainless steel), this base body being mechanically surface-treated, preferably brushed, and a nickel-tungsten layer on the surface-treated base body.

2. Object with a body made of metal or a body with metallic surfaces (no stainless steel), this Base body is mechanically surface-treated, preferably brushed, and a nickel layer, preferably sulfamate nickel layer, on the surface-treated base body, and a palladium located on the nickel layer

Nickel layer.

3. Object with a base body made of metal or a base body with metallic surfaces (no stainless steel), a layer of copper or nickel located on the base body, this copper layer or nickel layer being mechanically surface-treated, preferably brushed, and a nickel-tungsten layer and / or palladium-nickel layer on the surface-treated copper layer or nickel layer.

4. Object with a base body made of metal or a base body with metallic surfaces (no stainless steel), a copper layer on the base body, a nickel layer on the copper layer, this nickel layer being mechanically surface-treated, preferably brushed, and a nickel-tungsten Layer and / or a palladium-nickel layer on the surface-treated nickel layer. In the case of the object defined under 4, a further nickel layer can preferably be located between the surface-treated nickel layer and the nickel-tungsten layer or palladium-nickel layer.

5. Object with a base body made of plastic or a base body with plastic surfaces, a layer of copper or nickel located on the base body, this copper layer or nickel layer being mechanically surface-treated, preferably brushed, and - a nickel-tungsten layer on the surface-treated copper layer or nickel layer.

6.Object with a base body made of plastic or a base body with plastic surfaces - a copper layer on the base body, a nickel layer on the copper layer, this nickel layer being mechanically surface-treated, preferably brushed, and - a nickel-tungsten layer on the surface-treated nickel layer.

7. Object with a base body made of plastic or a base body with plastic surfaces, a layer of copper or nickel located on the base body, wherein this copper layer or nickel layer is mechanically surface-treated, preferably brushed, and a palladium-nickel layer on the surface-treated copper layer or nickel layer.

8. Object with a base body made of plastic or a base body with plastic surfaces, - a copper layer on the base body, a nickel layer on the copper layer, this nickel layer being mechanically surface-treated, preferably brushed, and - a palladium-nickel layer the surface-treated nickel layer.

For all objects defined under 3 and 4, the surface-treated nickel layer can preferably be a so-called sulfamate nickel layer. Such nickel layers are known to the person skilled in the art as soft matt nickel layers. The copper layers mentioned under 3. and 4. are preferably matt copper layers.

In the case of the objects defined under 6 and 8, a further nickel layer can preferably be located between the surface-treated nickel layer and the nickel-tungsten / palladium-nickel layer.

In all of the objects defined under 5th to 8th, the surface-treated nickel layer can preferably be a so-called sulfamate nickel layer. Such nickel layers are Known to those skilled in the art as soft matt nickel layers. The copper layers mentioned under 5 to 8 are preferably matt copper layers.

If there are additional nickel layers (between the surface-treated base body or surface-treated layer and the nickel-tungsten layer or palladium-nickel layer), these are preferably also so-called sulfamate nickel layers.

In all embodiments of the object according to the invention, there may be (at least) one siloxane / polysiloxane cover layer over the (optionally uppermost) nickel-tungsten layer or palladium-nickel layer.

Accordingly, a particularly preferred object according to the invention is defined by the following structure:

a basic body made of metal or a basic body with metallic

Surfaces, a copper layer on the base body, a nickel layer on the copper layer, preferably sulfamate nickel layer, which has been mechanically surface-treated, preferably brushed, a further nickel layer, preferably sulfamate nickel layer, on the surface-treated nickel layer, - a further nickel layer on this located nickel-tungsten layer and / or palladium-nickel layer, and a polysiloxane top layer located on the nickel-tungsten layer and / or palladium-nickel layer.

Another particularly preferred object according to the invention is defined by the following structure: a base body made of plastic or a base body with plastic surfaces, a copper layer on the base body, a nickel layer on the copper layer, preferably sulfamate nickel layer that has been mechanically surface-treated, preferably brushed, another nickel layer on the surface-treated nickel layer, preferably sulfamate nickel layer, - A nickel-tungsten layer located on this further nickel layer, and a polysiloxane cover layer located on the nickel-tungsten layer.

Yet another particularly preferred object according to the invention is defined by the following structure:

a base body made of plastic or a base body with plastic surfaces, - a copper layer on the base body, a nickel layer on the copper layer, preferably sulfamate nickel layer, which is mechanically surface-treated, preferably brushed, another nickel layer on the surface-treated nickel layer, preferably sulfamate nickel layer, a palladium-nickel layer located on this further nickel layer, and a polysiloxane cover layer located on the palladium-nickel layer. Basically, nickel-tungsten layers of any alloy composition can be used in the invention. However, the proportion of tungsten is preferably between 25 and 45 atomic percent, in particular between 30 and 40 atomic percent.

Basically, palladium-nickel layers of any alloy composition can be used in the invention. However, the palladium content is preferably at least 50 atomic percent, in particular at least 70 atomic percent. A palladium content of approximately 80 atom percent is further preferred. Due to the high palladium content, the layers obtained have a particularly good corrosion resistance, which can even be higher than that of stainless steel.

In principle, the layer thicknesses of the coatings applied to the object are not critical. However, in order to be able to perform their function particularly well, there are preferred ranges for these corresponding layer thicknesses. The layer thickness of the first metal layer on the object is between 10 μm and 60 μm, preferably between 20 μm and 50 μm. Within this latter range, layer thicknesses between 30 μm and 40 μm are further preferred.

The layer thickness of the nickel layers, preferably of the (further) nickel layers located on a surface-treated layer, is preferably between 5 μm and 25 μm, preferably between 5 μm and 15 μm. Within the latter range, layer thicknesses between 6 μm and 10 μm are particularly noteworthy.

The layer thicknesses of the nickel-tungsten layer (s) or palladium-nickel layer (s) are likewise not critical, but are chosen to be as small as possible (for example less than 20 μm). So are layer thicknesses between 0.1 μm and 5 μm. Within this range, layer thicknesses between 0.2 μm and 2 μm, in particular between 0.5 μm and 1 μm, are further preferred.

The layer thickness of the siloxane / polysiloxane layer (s) is preferably less than 5 μm, in particular less than 1 μm.

According to the invention, all known and, in particular, usually industrially used metals (with the exception of stainless steel) can in principle be coated. The object can either itself consist of the corresponding metal, or the metal can form at least part of the surface of this object. Base bodies made of metals such as are used in sanitary engineering are preferably used in the invention. To be emphasized here are base bodies made of aluminum, zinc (die-casting) and especially brass.

According to the invention, all known and in particular usually industrially used (galvanizable) plastics can be coated. The object can either itself consist of the corresponding plastic material or the plastic material can form at least part of the surface of this object. Base bodies made of plastics, as are used in sanitary engineering, are preferably used in the invention. In particular, the plastic is ABS (acrylonitrile-butadiene-styrene copolymer). PA (polyamide) and ABS / PC (ABS copolymer with polycarbonate) should also be emphasized.

In accordance with the object stated at the outset, the object according to the invention preferably has a so-called stainless steel look, ie a stainless steel appearance for the viewer. In front- this stainless steel look is preferably that of "brushed stainless steel".

The method according to the invention and the object according to the invention provide a solution to the problem explained at the beginning. The object according to the invention, especially when it is a sanitary object, fulfills both the functional requirements and the decorative requirements imposed on it. The object is on the one hand u. a. corrosion-resistant, abrasion-resistant, allows liquids to roll off well and has firmly adhering surface layers. On the other hand, it conveys the desired optics, in particular stainless steel optics, to the buyer / user, so that objects coated in this way do not stand out optically from objects made of the solid stainless steel material or from objects actually coated with stainless steel.

The invention further comprises an electrolyte for the galvanic deposition of nickel-tungsten surfaces, in particular on sanitary objects such as sanitary fittings. According to the invention, this electrolyte contains

Sodium tungstate dihydrate (Na ₂ WO 4 ^' 2 H ₂ 0), nickel sulfate hexahydrate (NiS0 ₄ ^■ 6 H ₂ 0), at least one complexing agent containing citric acid, preferably trisodium citrate dihydrate and / or citric acid monohydrate, ammonium chloride (NH ₄ CI), and optionally other additives.

The additives mentioned above can be all the usual additives, such as those used in the electrodeposition in the corresponding baths or electrolytes. in this connection For example, it can be gloss additives, wetting agents, surface-active substances and the like. Such additives can be used in different amounts, depending on the intended use.

It is preferred according to the invention if certain quantitative ranges of the above-mentioned components of the electrolyte are observed. The sodium tungstate dihydrate in the electrolyte is preferably contained in amounts between 80 g / l to 140 g / l, in particular 80 g / l to 100 g / l. The nickel sulfate hexahydrate is preferably present in the electrolyte according to the invention in amounts between 25 g / l to 50 g / l, in particular 25 g / l to 35 g / l. For the citric acid-containing complexing agent, amounts between 90 g / l to 150 g / l, in particular 100 g / l to 120 g / l (preferably as citric acid monohydrate), and for the ammonium chloride also acting as complexing agent, amounts between 15 g / l to 30 g / l, in particular 15 g / l to 20 g / l. Any gloss additives present are preferably present in amounts between 0 and 20 g / l. Preferred wetting agents are quantitative ranges between 0 and 1 g / l, in particular between 0.1 and 0.3 g / l, and for surface-active substances from 0 to 2 g / l.

The electrolyte according to the invention preferably has a pH between 7.5 and 8.5, with pH values between 7.6 and 8.2 being preferred.

Finally, the invention comprises a method for the galvanic deposition of nickel-tungsten surfaces, in particular on sanitary objects such as sanitary showers. In this method, the nickel-tungsten layers are deposited from an electrolyte, and preferably from the electrolyte according to the invention described above. Current densities between 0.5 and 3 A / dm ² and temperatures> 40 ° C, in particular between 50 ° C and 60 ° C, are indicated. applies. The objects to be coated can preferably be moved to improve the deposition behavior during the deposition process in the electrolyte, wherein movements between 0 and 1 m / s can be used in particular.

The above and other features of the invention result from the description of the following examples in conjunction with the claims. The individual features can be implemented individually or in combination with one another.

Examples

A. Base bodies of a fitting made of brass are provided for coating sanitary objects.

The following coating processes are carried out with such brass base bodies: - In the first case, the (in the polished state)

Brass base body directly subjected to a mechanical surface treatment, namely brushed and sandblasted. Then a nickel-tungsten layer is applied directly to the base body treated in this way.

In the second case, the brass body (which is in a polished state) is also directly brushed and sandblasted. A sulfamate nickel layer is then first applied to the surface-treated base body and then a palladium-nickel

Layer. In the third case, a copper layer and then a sulfamate nickel layer are first applied to the brass base body (which is present in the polished state). The nickel surface thus obtained is then brushed and sandblasted. After the mechanical surface treatment, a further layer of sulfamate nickel is electroplated onto the brushed / sandblasted surface. Either a nickel-tungsten layer or a palladium-nickel layer is then applied to this nickel layer.

In all cases, a commercially available brush disk is used for brushing, which is suitable for applying a brush structure typical of stainless steel parts with the corresponding grooves, depressions and the like. Those parts of the brass base body that cannot be processed well with the brush disk, such as. B. narrow transitions are processed by sandblasting.

The nickel-tungsten layers obtained in the first and third cases are electrodeposited from a corresponding electrolyte. The thickness of the nickel-tungsten layers is approx. 1 μm. The tungsten content of these layers is 40 atomic percent.

The two and three applied sulfamate nickel layers are galvanically deposited with a layer thickness of approx. 10 μm from a corresponding electrolyte. The copper layers applied first in the third case are likewise obtained galvanically from a corresponding electrolyte with layer thicknesses of approximately 40 μm. The palladium-nickel layers applied in the third case are likewise electroplated in a layer thickness of approximately 1 μm from a corresponding electrolyte. The palladium content of these layers is 80 atom percent.

In other versions, the above-mentioned metal-coated parts are sealed with a polysiloxane layer (layer thickness approx. 0.5 μm).

In all cases, the layer structure obtained is on the one hand identical in color to that of stainless steel, and on the other hand the (mechanically treated) surface structure obtained corresponds to that of brushed stainless steel. Thus, the parts coated according to the invention are optically indistinguishable from parts made of solid stainless steel or parts coated with stainless steel itself.

In those cases where a surface sealing with polysiloxane takes place, this final cover layer does not influence the visual appearance and the feel of the objects according to the invention. However, excellent repellency or dirt-repellent properties are achieved with this top layer. The polysiloxane cover layer is particularly easy to apply to the objects according to the invention due to the brushed / sandblasted surface structure and also adheres particularly well to these metal-coated objects.

The base body of a shower made of the plastic material ABS (acrylonitrile-butadiene-styrene-gopolymer) is provided for coating a sanitary object. This plastic part is galvanically coated with copper in the usual way (layer thickness approx. 40 μm). A so-called sulfamate nickel layer (matt nickel) is galvanically deposited on this copper layer (layer thickness approx. 10 μm). The nickel surface thus obtained is then brushed and sandblasted.

For the brushing, a commercially available brush disk is used, which is suitable for applying a brush structure typical of stainless steel parts with the corresponding grooves, depressions and the like. Those places of the plastic part that can not be processed well with the brush, such. B. narrow transitions are processed by sandblasting. After these mechanical surface treatments, a matt, well-structured metal-coated plastic part is obtained.

After the mechanical surface treatment, a further layer of sulfamate nickel is electroplated onto the brushed / sandblasted surface. In the present case, this layer has a thickness of approximately 8 μm.

An approximately 1 μm thick nickel-tungsten layer made of an electrolyte according to the invention is then electroplated onto this nickel layer. The tungsten portion of this layer is 40 atomic percent. The electrolyte used according to the invention contains the following components:

84.6 g / l sodium tungstate dihydrate 28.8 g / l nickel sulfate hexahydrate 1 12 g / l citric acid monohydrate - 17.7 gl / ammonium chloride. This electrolyte is also suitable for other applications for the deposition of nickel-tungsten layers.

The layer structure obtained is identical on the one hand to that of stainless steel and on the other hand the (mechanically treated) surface structure obtained corresponds to that of brushed stainless steel. Thus, the plastic parts coated according to the invention are optically indistinguishable from parts made of solid stainless steel or plastic parts coated with stainless steel.

In a final step, the metal-coated plastic part is sealed with a polysiloxane layer (layer thickness approx. 0.5 μm). This final cover layer does not influence the visual appearance and the feel of the object according to the invention. However, excellent repellency or dirt-repellent properties are achieved with this top layer. The polysiloxane cover layer is particularly easy to apply to the metal-coated object due to the brushed / sandblasted surface structure and also adheres particularly well to this metal-coated object.

To coat a sanitary object, the base body of a shower is made of the plastic material ABS (acrylonitrile

Butadiene-styrene copolymer) is provided.

This plastic part is galvanically coated with copper in the usual way (layer thickness approx. 40 μm). A so-called sulfamate nickel layer (matt nickel) is galvanically deposited on this copper layer (layer thickness approx. 10 μm). The nickel surface thus obtained is then brushed and sandblasted. For the brushing, a commercially available brush disk is used, which is suitable for applying a brush structure typical of stainless steel parts with the corresponding grooves, depressions and the like. Those places of the plastic part that can not be processed well with the brush, such. B. narrow transitions are processed by sandblasting. After these mechanical surface treatments, a matt, well-structured metal-coated plastic part is obtained.

After the mechanical surface treatment, a so-called sulfamate nickel layer is electroplated onto the brushed / sandblasted surface. In the present case, this layer has a thickness of approximately 8 μm. An approximately 1 μm thick palladium-nickel layer is then electroplated onto this nickel layer. The

The proportion of palladium in this layer is 80 atomic percent, so that excellent corrosion properties are achieved. The corrosion resistance is even better than that of stainless steel. The layer structure obtained is, on the one hand, identical in color to that of stainless steel and, on the other hand, the (mechanically treated) surface structure obtained corresponds to that of brushed stainless steel. Thus, the plastic parts coated according to the invention are optically indistinguishable from parts made of solid stainless steel or plastic parts coated with stainless steel.

In a final step, the metal-coated plastic part is sealed with a polysiloxane layer (layer thickness approx. 0.5 μm). This final cover layer does not influence the visual appearance and the feel of the object according to the invention. However, this top layer gives excellent repellency or dirt-repellent properties reached. The polysiloxane cover layer is particularly easy to apply to the metal-coated object due to the brushed / sandblasted surface structure and also adheres particularly well to this metal-coated object.

Claims

claims

1. A method for coating objects, in particular sanitary objects such as sanitary fittings, sanitary showers and the like, in which at least one layer of copper, nickel or a copper-nickel alloy is optionally applied to the object, - the object and / or at least the uppermost one applied layer is mechanically surface-treated, and at least one nickel-tungsten layer and / or at least one palladium-nickel layer is applied.

2. The method according to claim 1, characterized in that the objects consist of metal or have metallic surfaces, stainless steel being excluded as the metal.

3. The method according to claim 1, characterized in that the objects consist of plastic or have plastic surfaces.

4. The method according to claim 3, characterized in that at least the uppermost layer applied is mechanically surface-treated.

5. The method according to any one of the preceding claims, characterized in that the surface treatment is carried out by brushing and / or blasting, in particular sandblasting.

6. The method according to any one of the preceding claims, characterized in that first a copper layer on the object and then a nickel layer is applied and this nickel layer is mechanically surface-treated.

7. The method according to any one of the preceding claims, characterized in that the nickel layer is a so-called

Sulfamate nickel layer acts.

8. The method according to any one of the preceding claims, characterized in that on the surface-treated object and / or on the surface-treated layer before application of the

Nickel-tungsten layer or the palladium-nickel layer, at least one further layer of copper, nickel or a copper-nickel alloy is applied.

9. The method according to claim 8, characterized in that the further layer is a nickel layer, preferably a so-called sulfamate nickel layer.

10.A method according to one of the preceding claims, characterized in that the applied metal layers are at least partially, preferably all, applied by electrodeposition.

1 1.Procedure according to one of the preceding claims, characterized in that at least one siloxane and / or polysiloxane cover layer is applied over the nickel-tungsten layer or the palladium-nickel layer.

12. Object, preferably a sanitary object such as a sanitary fitting, sanitary shower and the like, characterized in that it is constructed as follows: a basic body, optionally at least one layer of copper, nickel or a copper-nickel alloy located on the base body, the base body and / or at least the optionally top layer being mechanically surface-treated, and at least one nickel-tungsten layer and / or at least a palladium-nickel layer over the surface-treated base body or over the surface-treated top layer.

13. An article according to claim 12, characterized in that the article consists of metal or has metallic surfaces, stainless steel being excluded as the metal.

14. Object according to claim 12, characterized in that the object consists of plastic or has plastic surfaces.

15. Object according to claim 14, characterized in that at least the uppermost layer applied is mechanically surface-treated.

16. Object according to one of claims 12 to 15, characterized in that the base body or the top layer is brushed and / or blasted, in particular sandblasted.

17. Object according to one of claims 12 to 16, characterized by at least one further layer of copper, nickel or a copper-nickel alloy between the surface-treated base body or the surface-treated layer and the nickel-tungsten layer and / or the palladium-nickel layer.

18. Object according to one of claims 12 to 17, characterized in that it is constructed as follows: a base body made of metal or a base body with metallic surfaces, stainless steel being excluded as metal, and wherein the base body is mechanically surface-treated, preferably brushed is, and - a nickel-tungsten layer on the surface-treated base body.

19. Object according to one of claims 12 to 17, characterized in that it is constructed as follows: - a base body made of metal or a base body with metallic surfaces, stainless steel being excluded as the metal, and wherein the base body is mechanically surface-treated, preferably brushed , and a nickel layer, preferably sulfamate nickel layer, on the surface-treated base body, and a palladium-nickel layer located on the nickel layer.

20. Object according to one of claims 12 to 17, characterized in that it is constructed as follows: a base body made of metal or a base body with metallic surfaces, stainless steel being excluded as metal, a layer of copper located on the base body or nickel, this copper layer or nickel layer being mechanically surface-treated, preferably brushed, and a nickel-tungsten layer and / or a palladium-nickel layer on the surface-treated copper layer or nickel layer.

21. Object according to one of claims 12 to 17, characterized in that it is constructed as follows: a base body made of metal or a base body with metallic surfaces, stainless steel being excluded as metal, - a copper layer located on the base body, one on the copper layer, this nickel layer being mechanically surface-treated, preferably brushed, and a nickel-tungsten layer and / or a palladium-nickel layer on the surface-treated nickel layer.

22. Object according to one of claims 12 to 17, characterized in that it is constructed as follows: a base body made of plastic or a base body with plastic surfaces, a layer of copper or nickel located on the base body, this copper layer or nickel layer mechanically is surface-treated, preferably brushed, and a nickel-tungsten layer on the surface-treated copper layer or nickel layer.

23. Object according to one of claims 12 to 17, characterized in that it is constructed as follows: a base body made of plastic or a base body with plastic surfaces, a copper layer on the base body, a nickel layer on the copper layer, this nickel layer being mechanically surface-treated, preferably brushed, and a nickel-tungsten layer on the surface-treated nickel layer.

24. Object according to one of claims 12 to 17, characterized in that it is constructed as follows: a base body made of plastic or a base body with plastic surfaces, a layer of copper or nickel located on the base body, said copper layer or nickel layer mechanically is surface-treated, preferably brushed, and a palladium-nickel layer on the surface-treated copper layer or nickel layer.

25. Object according to one of claims 12 to 17, characterized in that it is constructed as follows: a base body made of plastic or a base body with plastic surfaces, a copper layer located on the base body, a nickel layer located on the copper layer, this nickel layer mechanically surface-treated, preferably brushed, and a palladium-nickel layer on the surface-treated nickel layer.

26. Object according to one of claims 12 to 25, characterized in that between a surface-treated Nickel layer and the nickel-tungsten layer and / or palladium-nickel layer is another nickel layer.

27. The article of claim 26, characterized in that the surface-treated nickel layer is a so-called sulfamate nickel layer.

28. Object according to claim 26 or claim 27, characterized in that it is in the further nickel layer between the surface-treated nickel layer and the nickel

Tungsten layer and / or palladium-nickel layer is a so-called sulfamate nickel layer.

29. Object according to one of claims 12 to 28, characterized by a siloxane and / or polysiloxane cover layer over the

Nickel-tungsten layer and / or palladium-nickel layer.

30. Object according to claim 29, characterized in that it is constructed as follows: - A base body made of metal or a base body with metallic surfaces, a copper layer located on the base body, a nickel layer located on the copper layer, preferably sulfamate nickel layer, the mechanically surface-treated, preferably brushed, a further nickel layer located on the surface-treated nickel layer, preferably sulfamate nickel layer, a nickel-woifrarm layer and / or palladium-nickel layer located on this further nickel layer, and a siloxane / polysiloxane top layer located on the nickel-tungsten layer and / or palladium-nickel layer.

31. The article as claimed in claim 29, characterized in that it is constructed as follows: a base body made of plastic or a base body with plastic surfaces of a copper layer located on the base body, - a nickel layer located on the copper layer, preferably a sulfamate nickel layer, which is mechanically surface-treated, is preferably brushed, a further nickel layer located on the surface-treated nickel layer, preferably a sulfamate nickel layer, a nickel-tungsten layer located on this further nickel layer, and a siloxane / polysiloxane top layer located on the nickel-tungsten layer.

32. Object according to claim 29, characterized in that it is constructed as follows: a base body made of plastic or a base body with plastic surfaces, - a copper layer located on the base body, a nickel layer located on the copper layer, preferably sulfamate nickel layer, which mechanically treats the surface , preferably brushed, a further nickel layer, preferably sulfamate nickel layer, located on the surface-treated nickel layer, - όό ~

a palladium-nickel layer located on this further nickel layer, and a siloxane / polysiloxane cover layer located on the palladium-nickel layer.

33. Object according to one of claims 12 to 32, characterized in that the tungsten portion of the nickel-tungsten layer is between 25 and 45 atomic percent, preferably between 30 and 40 atomic percent.

34. Object according to one of claims 12 to 33, characterized in that the palladium portion of the palladium-nickel layer is at least 50 atomic percent, preferably at least 70 atomic percent, in particular approximately 80 atomic percent.

35. Object according to one of claims 12 to 34, characterized in that the layer thickness of the first metal layer located on the object, in particular a copper layer, between 10 microns and 60 microns, preferably between 20 microns and 50 microns, in particular between 30 microns and Is 40 μm.

36. Object according to one of claims 12 to 35, characterized in that the layer thickness of the nickel layers, preferably of the nickel layers located on the surface-treated base body or on a surface-treated layer, between 5 μm and 25 μm, preferably between 5 μm and 15 μm, is in particular between 6 μm and 10 μm.

37. Object according to one of claims 12 to 36, characterized in that the layer thickness of the nickel-tungsten layers or palladium-nickel layers is between 0.1 μm and 5 μm, is preferably between 0.2 μm and 2 μm, in particular between 0.5 μm and 1 μm.

38. Object according to one of claims 29 to 37, characterized in that the layer thickness of the siloxane / polysiloxane

Layer is less than 5 microns, preferably less than 1 micron.

39. Object according to one of claims 12 to 38, characterized in that the metal is brass.

40. Object according to one of claims 12 to 38, characterized in that the plastic is ABS.

41. Object according to one of claims 12 to 40, characterized in that it has a so-called stainless steel look.

42. Electrolyte for the galvanic deposition of nickel-tungsten surfaces, in particular on sanitary objects such as sanitary fittings, containing - sodium tungstate dihydrate,

Nickel sulfate hexahydrate, at least one citric acid-containing complexing agent, preferably trisodium citrate dihydrate and / or citric acid monohydrate, ammonium chloride, and optionally other additives.

43. Electrolyte according to claim 42, characterized in that it

80 g / l to 140 g / l, preferably 80 g / l to 100 g / l, sodium tungstate dihydrate,

25 g / l to 50 g / l, preferably 25 g / l to 35 g / l, nickel sulfate hexahydrate, 90 g / l to 150 g / l, preferably 100 g / l to 120 g / l, citric acid-containing complexing agent, and

15 g / l to 30 g / l, preferably 15 g / l to 20 g / l, ammonium chloride.

44. Electrolyte according to claim 42 or claim 43, characterized in that it has a pH between 7.5 and 8.5, preferably between 7.6 and 8.2.

45. A method for the galvanic deposition of nickel-tungsten surfaces, in particular on sanitary objects such as sanitary fittings, characterized in that nickel-tungsten layers made of an electrolyte, preferably of an electrolyte according to one of claims 42 to 44, at a current density between 0.5 and 3 A / dm ² and a temperature greater than 40 ° C and 60 ° C are deposited.