EP1622761A2

EP1622761A2 - Object

Info

Publication number: EP1622761A2
Application number: EP04727662A
Authority: EP
Inventors: Hartmut Sauer
Original assignee: AHC Oberflaechenechnik GmbH
Current assignee: Aalberts Surface Technologies GmbH Kerpen
Priority date: 2003-04-16
Filing date: 2004-04-15
Publication date: 2006-02-08
Also published as: WO2004092436A3; WO2004092436A2; JP2006523544A; US20060286348A1; DE202004020372U1; CA2522641A1

Abstract

The surface of the disclosed object is entirely or partially made of a composite material comprising a non-metallic substrate that contains at least one polymer, and of a metallic layer deposited thereon without an external current supply and having an adherence of at least 4 N/mm2. The boundary layer between the non-metallic substrate and the metallic layer has a calcium content of maximum 0.5 % by weight, as determined by EDX analysis of a polish of cross-section, relative to an analysis region of 1 x 1 νm whose centre passes through the boundary layer. Also disclosed are a process for producing said object and its use.

Description

object

The present invention relates to an object, the surface of which comprises, in whole or in part, a composite material consisting of a polymer and a metallic layer thereon.

Such objects are known and are used in particular in the decorative field, such as chrome-plated objects made of ABS (acrylic / butadiene / styrene plastics) or polymer blends, in particular moldings, shower heads, radiator grills for automobiles, coffee pots.

Such composite materials have no appreciable adhesive strengths, so that - regardless of the decorative properties - such objects cannot perform technical functions in the sense of wear protection, corrosion protection, stiffening, mechanical, thermal and / or chemical stress.

In the recent past there have been considerations to develop composite materials or surfaces from such composite materials with such functions.

One method for producing such layers is thermal spraying. Metallic particles are heated and accelerated onto the substrate to be coated. This enables metallic layers to be produced on plastics. With this method, however, only geometrically simple components can be coated. The main disadvantages of this method are also that the layers have a high porosity, high internal stress, high layer thicknesses and insufficient adhesion for mechanically highly stressed components.

Another possibility for the production of such composite materials is the vapor deposition of metal on plastic in a vacuum (CVD / PVD process). With this, closed metallic coatings are applied to non-metallic substrates, such as plastics. However, this method is economically unsuitable for components with larger dimensions. Furthermore, components with depressions or cavities are not completely metallized. The objects produced in this way have a metal layer with a thickness of at most 3 μm, which is not sufficient for many technical applications. Furthermore, these composite layers have only a very low adhesive strength.

A widely used area of application of this vapor deposition technique is the coating of plastic films, for example for food packaging. For example, DE 198 49 discloses 661 A1, to vapor-coat a special polyester film with aluminum, so that it has a high oxygen barrier, a good gloss and a low coefficient of friction. The adhesive strengths of up to 3 N / mm specified there are, however, too low to be able to exist in a mechanically stressed, functional application of the metallized film.

DE 43 12 926 A1 describes a method for improving the adhesive strength of dental metal-plastic composite layers. For this purpose, a metallic substrate, on which a polymer has already been applied, is irradiated with a special Te-C0 ₂ laser. If necessary, an adhesion promoter is also used. Metallization of plastic substrates is not described here.

DE 42 11 712 A1 also describes irradiating the surface of a substrate to improve the adhesive strength with an Eximer laser. A PET (polyethylene terephthalate) film is irradiated with this special laser so that it can subsequently be vapor-coated with a ferromagnetic metal layer using a PVD process. Such films are used inter alia as an audio or video recording medium.

There is also a process for special plastics in which the objects to be coated are first swollen with suitable substances and then chemically etched. The achieved adhesive strength of the applied metal layer on the plastic is a maximum of 2 N / mm ² .

A major disadvantage of this process is the considerable environmental pollution caused by the two chemical treatment agents, so that this process can no longer be used from an environmental point of view.

A further developed process for the metallization of polyamides, which is based on the above-described principle of swelling the surface of the plastic substrate but does not provide for pickling with chromosulfuric acid, is described in an article by GD Wolf and F. Funger "Metallized polyamide injection molded parts", Kunststoffe, 1989, Pp. 442-447. The surface of the amorphous polyamide is treated with an organometallic activator solution. This is followed by a conventional chemical nickel plating process. The disadvantage of this type of surface treatment, which is based on a chemical reaction of the treatment solution with the substrate, is that the swollen surfaces are very sensitive to environmental influences, such as dust deposits. Furthermore, the polyamide to be treated must be amorphous, since it is partly crystalline or crystalline Polyamides are not attacked by the method presented. This method therefore represents a complex process which can only be used to a limited extent in order to achieve adhesive composite layers between the polymeric substrate and the metal layer.

Furthermore, from the dissertation by H. Sauer, Siegen 1999, it is known to produce composite materials from a plastic and a metal layer thereon, the plastic surface being roughened using a blasting agent before the metallic layer is applied, and then with a special ethanol / calcium carbonate suspension is treated. Such composite materials have an extraordinarily high adhesive strength of the metal layer on the plastic substrate.

However, no larger areas can be produced on an industrial scale with the method described there. In addition, the layers obtainable in this way have the disadvantage that small amounts of calcium carbonate remain in the boundary layer between the plastic substrate and the metal layer, so that a “predetermined breaking point” arises. This

"Breakage point" leads to the fact that the adhesive strength at different points of an object is quite different. These deviations mean that the points with the lowest adhesive strengths lead to defects at an early stage in mechanically highly stressed objects.

The object of the present invention is to provide an object which can be subjected to extremely high mechanical loads and whose surface, in whole or in part, has a composite material consisting of at least one polymer and a metal layer which overcomes the disadvantages of the prior art described above.

The object is achieved according to the invention by an object, the surface of which has a composite material in whole or in part, the composite material consisting of a non-metallic substrate containing at least one polymer and an external currentlessly deposited metallic layer with an adhesive strength of at least 4 N / mm ² , and wherein the boundary layer located between the non-metallic substrate and the metallic layer has a calcium content, determined by EDX analysis of a cross section, of at most 0.5% by weight, based on an analysis area of 1 × 1 μm, the center of which runs through the boundary layer.

It should be noted that in a general embodiment the non-metallic substrate contains essentially no particles of metal oxides or metals. This means that in the cross-section substrate at a depth of more than 10 μm below the boundary between metallic layer and non-metallic substrate no corresponding particles can be detected analytically.

In contrast, it is possible for the boundary layer to contain particles of metal oxides or metals in small quantities down to a depth of 10 μm, which particles originate, for example, from the blasting agent for roughening the non-metallic substrate surface.

In contrast, in special embodiments in which glass-fiber or ceramic-reinforced polymers are used as the non-metallic substrate, particles of metal oxides in the cross-section are to be detected in the entire non-metallic substrate. Commercial examples of such glass fiber reinforced plastics are Grivory HTV-6H1,

Grivory HAT-PPA or Grivory GM-4H from EMS-GRIVORY. Commercial examples of ceramic reinforced plastics are Ryton BR111 and Ryton BR111BL from Chevron Phillips Chemical Company LP.

The object can - depending on the polymer-containing material used - by so-called

Rapid prototyping processes, in particular by stereolithography or by laser sintering. As a result, complex shapes can be produced in a short time, which are coated evenly with the metallic layer deposited without external current, without reinforcements in the edge region or weakening in the region of depressions or undercuts.

To determine the calcium content and the roughness values R _a and R _z , a sample is taken from an object according to the invention and a cross-section is made in accordance with the method described below.

In a further embodiment, an object according to the invention is preferred, the surface of which has a composite material in whole or in part, this composite material having a first non-metallic layer and a second metallic layer applied thereon, and wherein a) the surface of the object does not exist prior to application of the electrolessly deposited metallic layer is chemically pretreated; and b) the metal layer deposited without external current is not applied by thermal spraying, CVD, PVD or laser treatment.

Chemical pretreatment is understood here and below as a differentiation from mechanical treatments to any treatment of a substrate surface by pickling, etching, swelling, vapor deposition, plasma treatment, laser treatment or the like Methods is carried out and in which a change in the surface is caused by a chemical reaction.

In contrast to the prior art metallized articles after chemical pretreatment, the articles according to the present invention have a rough, sharp-edged boundary layer between the non-metallic layer and the metal layer applied without external current. These sharp-edged bulges and undercuts in the boundary layer are clearly recognizable as angular surface contours, for example in a cross-section analysis, the design of which is described below. In this way, they can be distinguished from the more rounded, but in any case rounded, contours that result from chemical pretreatment (Figure 2).

In cross-section production, there is a particular difficulty that the interface between the substrate and the surface can be very quickly destroyed or detached by processing. To avoid this, a new cutting wheel from Struer type 33TRE DSA No. 2493 is used for every cross-section production. In addition, care must be taken to ensure that the contact pressure that is transferred from the cutting disc to the substrate coating is directed so that the force runs from the coating towards the substrate. When separating, make sure that the

Contact pressure is kept as low as possible.

The sample to be examined is placed in a transparent investment material (Epofix putty, available from Struer). The embedded sample is ground on a table grinding machine from Struer, type KNUTH-ROTOR-2. Different sanding papers with silicon carbide and different grain sizes are used. The exact

Order is as follows:

Water is used during the grinding process to remove the abrasive particles. The tangential force that occurs on the cross-section and arises from friction is directed so that the metallic layer is pressed against the non-metallic substrate. This effectively prevents the metallic layer from becoming detached from the non-metallic substrate during the grinding process.

The sample treated in this way is then polished using a motor-operated preparation device of the DAP-A type from Struer. The usual sample winder is not used, rather the sample is only polished by hand. Depending on what is to be polished

Substrate a speed between 40 to 60 U / min and a pressing force between 5 and 10 N is applied.

The cross section is then subjected to an SEM image. To determine the magnification of the boundary line, the boundary line of the layer between the non-metallic substrate and the metallic surface is determined at a magnification of 10,000 times. to

Evaluation, the program OPTIMAS from Wilhelm Mikroelektronik is used. As a result, X-Y value pairs are determined that describe the boundary line between the substrate and the layer. A distance of at least 100 μm is required to determine the enlargement of the boundary line in the sense of the present invention. The course of the boundary line must be determined with at least 10 measuring points per μm. The enlargement of the boundary line is determined from the quotient of true length by geometric length. The geometric length corresponds to the distance of the measuring section, i.e. between the first and last measuring point. The true length is the length of the line that runs through all recorded measurement points.

The surface roughness value R _{a is} determined according to the DIN 4768 / ISO 4287/1 standard, also using the XY value pairs previously recorded.

The R _a value is a measurement-reproducible measure of the roughness of surfaces, whereby profile outliers (ie extreme valleys or hills) are largely neglected due to the area integration.

The adhesive strengths (specified in N / mm ² ) of the composite materials according to the invention are determined exclusively on the basis of the forehead tensile test according to DIN 50160: the forehead tensile test (vertical tensile test) according to DIN 50160 has been used for years to test

Semiconductors, the determination of the adhesive tensile strength of thermally sprayed layers and used in various coating technologies.

To determine the adhesive strength in the forehead tensile test, the layer / substrate composite to be tested is glued between two test stamps and subjected to uniaxial brisk force until it breaks (see Figure 1). If the adhesive strength is greater than that of the coating and there is a break between the layer and the substrate, the equation can be used F max

° H exp ~ A

(with 0H _e x ^ experimentally detectable adhesive strength, F _max : maximum force at break of the bond and A _G : geometric fracture area) the adhesive strength can be calculated.

In the case of the basic materials of the prior art, which hold a metallic layer on a microstructured plastic surface, traces of calcium carbonate can be detected due to the manufacturing process. These impurities are introduced through the required pretreatment using a suspension of ethanol and calcium carbonate. A possible explanation for the improved uniformity of the adhesive strength in the objects according to the present invention can be seen in the fact that the remaining proportion of foreign constituents is reduced in such a way that it no longer acts as a separating agent or separating layer between the plastic surface and the metallic layer.

The proportion of calcium in the interface is determined using EDX spectroscopy.

Examples of such an object according to the invention are pump housings and corresponding rotors (impeller) of fuel pumps for the automotive industry. These objects are made of thermoplastics, in particular of polyoxymethylene (POM) and polyphenylene sulfide (PPS). The phenolic resin PF is particularly preferably used. After the pretreatment described above, these fuel pump parts are coated with a chemical nickel layer in a thickness of 5 μm without external current. The corresponding objects according to the invention are distinguished by a particularly high level of protection against corrosion and wear. The service life of the objects produced in this way is increased by a factor of 100 compared to that of the prior art.

In a preferred embodiment of the present invention, the boundary layer between the non-metallic substrate and the metallic layer has a roughness with an R _z value of at most 35 μm. The R _z value is a measure of the average vertical surface fissure. According to a further embodiment of the present invention, the non-metallic substrate contains at least one fiber-reinforced polymer, in particular a carbon fiber-reinforced polymer, and the diameter of the fiber is less than 10 μm. According to a further, likewise preferred embodiment of the present invention, the boundary between the non-metallic substrate and the metallic layer has a roughness with an R _z value of at most 100 μm and the non-metallic substrate contains at least one fiber-reinforced polymer, in particular a glass fiber-reinforced polymer, wherein the diameter of the fiber is more than 10 μm.

Especially for the use of fiber-reinforced polymers with a fiber thickness of more than 10 μm, it is important to achieve the lowest possible R _z values. With this combination it is surprisingly possible to achieve high adhesive strengths - in relation to the large fiber diameters used - of low R _z values.

Insofar as the composite materials are not only subject to thermal stresses, but also mechanical reinforced plastics are particularly preferably used, in particular carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GFK), plastics reinforced by aramid fibers or plastics reinforced by mineral fibers. With the provision of these items, a high stiffness will result

Components achieved with low weight, which are interesting for their industrial use due to their low costs. In particular, glass fiber-reinforced polymers as part of the non-metallic substrate, which have fibers with a diameter greater than 10 μm, are very inexpensive and easy to process. The fiber diameter has a great influence on the roughness, so that in such materials the present invention is achieved a roughness value R _a of at most 10 microns in accordance with. At the same time, it is possible according to the invention to achieve excellent values for the adhesive strength. In addition, the objects according to the invention have a high uniformity of adhesion. For the first time, this makes it possible to significantly increase the service life for the stressed component. Because even local delamination of the layer composite leads to failure of the entire component. The advantage is particularly serious in the case of components with a surface covered by the layer composite of more than 10 dm ² , that is to say in the case of large components or components with a large surface. In this way, articles of high rigidity and very low weight are obtained, which show excellent adhesion of the metallic layer. This

Property profile is interesting for a wide range of technical applications, such as the aerospace industry and the automotive industry. According to a preferred embodiment, the non-metallic substrate is also the surface of the object. These surfaces are preferably based on a polymeric material. Fiber-reinforced plastics, thermoplastics and other industrially used polymers are particularly preferred.

Equally, however, it is also possible to use objects whose non-detail substrate is not the surface of the object. Thus, the object can consist of a metallic or ceramic material that is coated with a non-metallic substrate that contains at least one polymer. Examples of such substrates are painted components (e.g. EX protection for painted objects) and anodized or hard anodized aluminum components with a polymer layer on the conversion layer.

According to a preferred embodiment, the standard deviation of the adhesive strength of the metallic layer at six different measured values distributed over the surface of the composite material is at most 25%, in particular at most 15%, of the arithmetic mean. In this way, the resulting components can be subjected to even greater mechanical stress.

The polymer of the non-metallic substrate is preferably selected from the group of polypropylene, polytetrafluoroethylene, polyamide, polyethylene, polyvinyl chloride, polystyrene, epoxy resins, polyether ether ketone, polyoxymethylene, polyformaldehyde, polyacetal, polyurethane, polyetherimide, polyphenylsulfone, polyphenylene sulfide, polyarylamide and polyarylamide, polycarbonate.

In cases where the non-metallic layer contains either polypropylene and / or polytetrafluoroethylene, adhesive strengths of at least 5 N / mm ^{2 are} achieved. This represents an excellent value, especially in connection with the high uniformity of the adhesive strength, which could not be achieved so far.

It is thus possible for the first time to provide articles with a composite material which have special properties with regard to their wettability, their permeability to certain substances (permeability) or also with regard to their compatibility with blood and blood plasma. Such objects made of polytetrafluoroethylene could be used, for example, in medical technology, as a membrane for pumps or in

Find fuel cell technology. According to a further, likewise preferred embodiment of the present invention, the metal layer deposited without external current is a metal alloy or metal dispersion layer.

In this way, objects with a composite material can be provided for the first time which have excellent adhesion of the metallic layer to the non-metallic substrate. The uniformity of the adhesion of the metallic layer also plays an important role in the suitability of these objects as highly stressed components for industrial machines. A targeted selection of the non-metallic substrate and the metallic layer on it enables an exact adaptation of the property profile to the conditions of the area of application. So it is for

For example, it is important to set a precisely defined adhesive strength for CFRP rollers that are used in a length between 1,000 and 12,000 mm with a line load that is constant over the entire length, so that the roller withstands the requirements for the entire service life.

Particular preference is given to the non-metallic substrate of the invention

A copper, nickel or

Gold layer applied.

However, a metal alloy or metal dispersion layer deposited without external current can also be applied, preferably a copper, nickel or gold layer with embedded non-metallic particles. The non-metallic particles can have a hardness of more than 1,500 HV and can be selected from the group of silicon carbide, corundum, diamond and tetraborarbide. In addition to the properties described above, these dispersion layers therefore have further functions, for example the wear resistance, surface wetting or emergency running properties of the objects according to the invention can be improved.

The non-metallic particles can also preferably have friction-reducing properties and be selected from the group of polytetrafluoroethylene, molybdenum sulfide, cubic boron nitride and tin sulfide.

In a further, particularly preferred embodiment of the present invention, the metallic layer of the invention is deposited on the electrolessly deposited metal layer

Object applied a layer of aluminum, titanium or their alloys, the surface of which is anodized or ceramized. Such anodically oxidized or ceramicized layers of aluminum, titanium or their alloys are known on metallic objects and are sold for example under the name Hart-Coat ^® or Kepla-Coat ^® by the company AHC Oberflächentechnik GmbH & Co. OHG. These layers are characterized by a particularly high hardness and a high operating resistance and mechanical

Stresses.

One or more further metallic layers can be arranged between the metallic layer of the object according to the invention deposited without external current and the layer of aluminum, titanium or their alloys.

The further metallic layers arranged between the electrolessly deposited layer and the aluminum layer are selected depending on the intended use. The choice of such intermediate layers is well known to the person skilled in the art and is described, for example, in the book "The AHC Surface - Manual for Construction and Manufacturing", 4th extended edition 1999.

It is also possible for the surface of such an object to be a ceramic oxide layer made of aluminum, titanium or their alloys, which is colored black by the inclusion of foreign ions. The ceramic oxide layer made of aluminum, titanium or their alloys, colored black by foreign ions, is of particular interest for high-quality optical elements, especially in the aerospace industry.

The production of ceramic oxide layers colored black by foreign ion incorporation is described, for example, in US-A-5035781 or US-A-5075178. The production of oxide ceramic layers on aluminum or titanium is for example in the

EP 0 545 230 B1. The production of anodically produced oxide layers on aluminum is described for example in EP 0 112 439 B1.

The objects of the present invention are particularly preferably obtained using a special method which comprises the following steps: i. the surface of the non-metallic layer is not chemically pretreated before the metallic layer is applied without external current; ii. the surface of the non-metallic layer is microstructured in a first step by means of a blasting agent; in. the metallic layer is then applied by electroless metal deposition. The objects according to the present invention initially have a non-metallic substrate as a composite material which contains at least one polymer. To produce the composite material according to the invention, the surface of the non-detail substrate is microstructured in a first step by means of a blasting treatment. The method used is described for example in DE 197 29 891 A1. As

Abrasives are particularly wear-resistant, inorganic particles. It is preferably copper-aluminum oxide or silicon carbide. It has proven to be advantageous that the blasting agent has a particle size between 30 and 300 μm. Other suitable blasting agents are steel and aluminum in different compositions and grain sizes, glass blasting beads, corundum, ceramic beads, plastic resins,

Silicon carbide, nutshells and other blasting media known to the person skilled in the art. It is further described there that a metal layer can be applied to the roughened surfaces by means of a metal deposition without external current.

As the process designation already says, in the case of metal deposition without external current, no electrical energy is supplied from the outside during the coating process, but the metal layer is only deposited by a chemical relation. The metallization of non-conductive plastics in a chemically reductive metal salt solution requires a catalyst on the surface in order to disrupt the metastable balance of the metal reduction bath and to deposit metal on the surface of the catalyst. This catalyst consists of precious metal nuclei such as palladium, silver, gold and occasionally copper, which are deposited on the plastic surface from an activator bath. It is preferred, based on process engineering, however, activation with palladium seeds.

Essentially, the substrate surface is activated in two steps. In a first step, the component is immersed in a colloidal solution (activator bath). The palladium nuclei that are necessary for metallization and are already present in the activator solution are adsorbed on the plastic surface. After germination, the tin-II or tin-IV oxide hydrate additionally formed when immersed in the colloidal solution is dissolved by rinsing in an alkaline, aqueous solution (conditioning) and the palladium seed is thereby exposed. After rinsing, chemical reduction baths can be nickel-plated or copper-plated.

This is done in a bath kept in a metastable equilibrium by a stabilizer, which contains both the metal salt and the reducing agent. The baths for the nickel or copper deposition have the property of the metal ions dissolved in them reduce germs and deposit elemental nickel or copper. In the coating bath, the two reactants have to approach the noble metal nuclei on the plastic surface. The resulting redox reaction creates the conductive layer, the noble metal nuclei taking up the electrons of the reducing agent and releasing them again when a metal ion approaches. This reaction releases hydrogen. After the palladium nuclei have been coated with nickel or copper, the applied layer takes on the catalytic effect. This means that the layer grows together from the palladium seeds until it is completely closed. The deposition of nickel is dealt with here as an example. At the

Coating with nickel, the germinated and conditioned plastic surface is immersed in a nickel metal salt bath, which allows a chemical reaction in a temperature range between 82 ° C and 94 ° C. The electrolyte is generally a weak acid with a pH between 4.4 and 4.9.

The thin nickel coatings applied can be reinforced with an electrolytically deposited metal layer. Coating components with layer thicknesses> 25 μm is not economical due to the low deposition rate of chemical coating processes. Furthermore, only a few coating materials can be deposited with the chemical coating processes, so that it is advantageous to use electrolytic processes for other technically important coating materials. Another important point is the different properties of chemically and electrolytically deposited layers with layer thicknesses> 25 μm, for example leveling, hardness and gloss. The basics of electrolytic metal deposition can be found in B. Gaida, "Introduction to electroplating", EG Leuze-Verlag, Saulgau, 1988 or in H. Simon, M. Thoma, "Applied surface technology for metallic materials", C. Hanser-Verlag, Munich (1985).

Plastic parts that have an electrically conductive layer due to an electroless coating process differ only insignificantly from those of the metals in terms of electrolytic metallization. Nevertheless, some points should not be neglected in the electrolytic metallization of metallized plastics. Due to the mostly low conductive layer thickness, the current density must be reduced at the beginning of the electrolytic deposition. If this point is not observed, the conductive layer may peel off and burn. Furthermore, care should be taken to ensure that annoying tarnish layers are removed using specially designed paper baths. Furthermore, residual stresses can destroy the layer. When depositing nickel layers from an ammoniacal bath, tensile stresses of the order of 400 to 500 MPa occur, for example. Using additives such as saccharin and butynediol, a change in the structure of the nickel coatings in the form of a changed grain size and the formation of micro-deformations can promote the reduction of internal stresses, which can have a positive effect on a possible premature coating failure.

Examples of metal layers applied without external current are described in detail in the manual of the company AHC Oberflächentechnik ("The AHC surface" manual for construction and manufacture, 4th edition, 1999).

One or more further layers, in particular metallic, ceramic, as well as crosslinked or hardened polymer layers, can be arranged on the metallic layer of the object according to the invention.

For example, it is possible to apply a further electrolytically deposited nickel layer to a nickel layer deposited without external current as the metallic layer of the present invention and to deposit a chrome layer thereon. The surfaces obtained in this way can be applied to rollers which must have a high surface quality and a high mechanical strength. The electrolytic deposition of the second nickel layer is carried out in order to be able to produce larger layer thicknesses inexpensively.

Furthermore, the objects of the present invention can have a copper layer as a metallic layer, to which a tin or a further copper layer can subsequently be applied. Then, for example, a gold layer is applied to the existing metal layers. Such coatings can be used, for example, for EMC shielding of electronic components or to improve the thermal conductivity of the coated objects.

The objects according to the present invention can also have a nickel layer as a metallic layer, to which a further nickel layer is applied. In this way it is possible to achieve a high degree of rigidity of the resulting plastic parts and thus to ensure an application for mechanically stressed components such as for example for gear wheels, suspensions or housing parts. Furthermore, as a metallic layer on an object according to the present

Invention present a copper layer which can be coated with a nickel layer and then with a chrome layer. A possible application of such a counter Standes consists of being used as a quickly positionable mirror in copiers and in laser technology.

In a further application example of the present invention, an epoxy resin can be applied to a nickel layer deposited without external current. The surface of this epoxy resin is then covered again with a nickel layer. In this way, diffusion-resistant components for the petrochemical industry can be produced against hydrocarbons, such as pipes and housings for the complete absorption of pumps, even under high pressure.

A particularly industrially preferred embodiment is filter housings for high-frequency components in the telecommunications industry, in particular for the transmission mast unit in the mobile radio sector. These are objects made of PPS / PEI, the entire surface of which is first coated with a chemically applied electroless nickel / phosphorus alloy in a layer thickness of 6 μm and then with an electrolytically applied silver layer in a thickness of 6 μm. Until now, such objects were made of aluminum, then nickel-plated and finally silver-plated. These prior art items have significant corrosion problems, particularly in metropolitan areas contaminated with exhaust gas. Until now, these filter housings had to be replaced every 6 months. In contrast, the duration of use can be increased to more than 2 years with the object according to the invention.

Furthermore, these further metallic layers, which are applied to the already existing metallic layer of the object according to the invention, can be used not only electrolytically but also with the aid of other methods such as CVD / PVD or thermal

Syringes can be applied to an object with a metallic layer of the present invention.

In this way, it is possible to apply aluminum or stainless steel to an object which, for example, consists of plastic and is provided with a nickel layer according to the present invention.

Another interesting example of an object according to the invention is a plastic which is initially provided with a nickel layer applied without external current. Layers of silver and gold are subsequently applied electrolytically to this nickel layer. Such a rather special layer sequence is used in medical technology for components for diagnostic devices. Overall, the examples given above show that the objects according to the invention can be used in a very wide range of technical applications.

An article according to the present invention can, for example, be a roller for the web processing industry (foils, paper, textiles, printers), a component of

Turbomolecular pumps (ring for the compressor stage), handle for household appliances (pots, lids), components for the aerospace industry (handle, handrail) and the aerospace industry (sun sail), component for the electronics industry (capacitor, sound field capacitor, sound tab, microwave waveguide, switch surface, Antenna, antenna housing), component for the moving components of cyclones, air classifier, mechanically, thermally and / or chemically stressed component for the automotive industry (brake pistons for automobiles) or a mold or component for the injection molding industry.

Example (according to the invention)

A plate made of polyamide 6 with the dimensions 200 * 100 * 12 mm with an initial roughness of R _a = 0.64 μm and R _z = 7.5 μm was surface-treated: The surface pretreatment is carried out with a modified pressure jet system from Straaltechnik International , The blasting system is operated at a pressure of 4 bar. A boron carbide nozzle with a diameter of 8 mm is used as the jet nozzle. The beam duration is 4.6 s. SiC with P80 grit with an average grain diameter of 200 to 300 μm is used as the abrasive. In order to adapt the blasting system specifically to the requirements of plastic modification with regard to reproducible surface topographies, 2 pressure circuits were installed, one each for the transport of the blasting medium and the actual acceleration process. This modification resulted in a very constant volume flow and a large pressure range. A stream of compressed air transports the abrasive to the nozzle at the lowest possible pressure. The flow conditions ensure, caused by a high volume flow of the blasting medium and a low proportion of compressed air, a low wear of the system and the blasting medium. The cross section is only reduced at the end of the transport hose in front of the mixing nozzle in order to set the desired volume flow. A constant volume flow of 1 l / min was specified for all plastic pretreatments. In the second part of the system, compressed air (volume flow 1) flows up to the nozzle

Pressure range from 0.2-7 bar can be set continuously. The blasting agent, which with a very small flow rate is conveyed into the mixing nozzle, is then accelerated by the high flow rate of the compressed air flow.

The roughened plate is treated in an ultrasonic bath with a mixture of deionized water and 3% by volume butyl glycol for five minutes.

The bath series used for the metal deposition of the conductive layer are based on the well-known colloidal palladium activation in connection with a final catalyzed metal reduction. All of the bath rows required for this were purchased from Max Schlötter. The diving sequences, treatment times and temperatures specified by the manufacturer were observed in all process steps of nickel deposition:

(1) Activator pre-immersion solution:

Used to avoid the introduction of contaminants and to completely wet the sample before the surface is actually activated.

Diving time: 2 min, room temperature

(2) Activator GS 510:

Activation of the surface with tin / palladium colloid. Diving time: 4 min, room temperature (3) rinsing baths: deionized water

Avoidance of activator GS 510 components by rinsing in deionized water. Diving time: 1 min, room temperature

(4) Conditioner 101: Conditioning the material surface by detaching annoying tin compounds from the surface. Diving time: 6 min, room temperature

(5) Rinse baths: deionized water. Diving time: 1 min, room temperature (6a) SH 490 LS chemical nickel bath:

Metallize the plastics with a bright, semi-gloss amorphous layer at a deposition temperature of 88-92 ° C. Diving time: 10 min

The chosen immersion time in the nickel bath resulted in a layer thickness of 1.4 μm. This

The thickness of the nickel layer is sufficient for an electrolytic coating. All process steps that were necessary for the deposition of the conductive layer were carried out in 50 l plastic trays, with a nickel temperature of 90 ° + 0.5 ° C being maintained during the entire coating cycle by means of an additional heating plate with temperature control. In order to obtain a uniform and reproducible layer quality, the bath series were analyzed and supplemented after a throughput of 20 samples according to the Max Schlötter company.

After the nickel conductive layer had been chemically applied, the sample was cooled from approx. 90 ° C. to approx. 60 ° C. in distilled water in order to then be electrolytically coated with nickel at 55 ° C. This intermediate step served to avoid the formation of reaction layers and to exclude residual stresses caused by rapid cooling. The samples, which were exclusively coated with a nickel conductive layer, slowly cooled down to 25 ° C in a distilled water bath.

The cross-section examination by SEM (1,500 times and 3,000 times) are shown in the following figures (Figure 3).

Evaluation of the EDX analysis showed a residual amount of calcium of 0.03% by weight.

The results of the adhesion tests are shown in Table 1.

Table 1

Comparative example (not according to the invention)

The example according to the invention is repeated, but after the blasting treatment the

Plate treated in an ultrasonic bath in a suspension of 5 wt .-% CaC0 ₃ in 96% ethanol for 5 minutes.

The plate is then treated in a further ultrasonic bath with pure, 96% ethanol for a further five minutes.

The cross section examination by SEM (1,500 times and 3,000 times) are in the following

Figures (Figure 4) reproduced. The evaluation of the EDX analysis showed a residual amount of calcium of 0.91 wt .-%, which comes from the treatment of the CaC0 ₃ / ethanol suspension. The results of the adhesive strength tests are shown in Table 2.

Table 2

The results clearly show a significant difference in the standard deviation of the adhesive strength of the various measured values distributed over the surface of the composite material. This difference, for example in the manufacture of rollers for the printing industry, means that rollers with a coefficient of variance of more than 25% show local detachments of the metal layer from the roughened plastic substrate during the necessary post-treatment by grinding, which can be attributed to lower adhesive strengths. Comparable rolls according to the present invention show no detachment during the grinding process. Reference symbol list Figure 1:

(1) Zugstempel

(2) glue

(3) metal layer

(4) substrate

Claims

Patent claims

1. Object, the surface of which comprises a composite material in whole or in part, the composite material consisting of a non-metallic substrate containing at least one polymer and an external currentlessly deposited metallic layer with an adhesive strength of at least 4 N / mm ² , characterized in that the boundary layer located between the non-metallic substrate and the metallic layer has a calcium content, determined by EDX analysis of a cross section, of at most 0.5% by weight, based on an analysis area of 1 × 1 μm, the center of which runs through the boundary layer.

2. The article of claim 1, the surface of which comprises a composite material, in whole or in part, this composite material having a first non-metallic layer and a second metallic layer applied thereon, characterized in that a) the surface of the object is not chemically pretreated before the metallic layer is applied becomes; and b) the metallic layer is not applied by thermal spraying, CVD, PVD or laser treatment.

3. Object according to claim 1, characterized in that the boundary between the non-metallic substrate and the metallic layer has a roughness with an R _z value of at most 35 μm.

4. Article according to claim 1, 2 or 3, characterized in that the non-metallic substrate contains at least one fiber-reinforced polymer, in particular a carbon fiber-reinforced polymer, and the diameter of the fiber is less than 10 microns.

5. Object according to claim 1, characterized in that the boundary between the non-metallic substrate and the metallic layer has a roughness with an R _z value of at most 100 μm and that the non-metallic sub- strat contains at least one fiber-reinforced polymer, in particular a glass fiber-reinforced polymer, and the diameter of the fiber is more than 10 microns.

6. Article according to one of the preceding claims, characterized in that the non-metallic substrate is the surface of the article.

7. Article according to one of claims 1 to 5, characterized in that the non-metallic substrate is not the surface of the article.

8. Object according to one of the preceding claims, characterized in that the standard deviation of the adhesive strength of the metallic layer at six different measured values distributed over the surface of the composite material is at most 25%, in particular at most 15%, of the arithmetic mean.

9. Article according to one of the preceding claims, characterized in that the polymer is selected from the group of polypropylene, polytetrafluoroethylene, polyamide, polyethylene, polyvinyl chloride, polystyrene, epoxy resins, polyether ether ketone, polyoxymethylene, polyformaldehyde, polyacetal, polyurethane, polyether imide , Polyphenyl sulfone, polyphenylene sulfide, polyarylamide, polycarbonate and polyimide.

10. Object according to one of the preceding claims, characterized in that the electrolessly deposited metal layer is a metal alloy or metal dispersion layer.

11. Object according to one of the preceding claims, characterized in that the metal layer deposited without external current is a copper, nickel or gold layer.

12. An article according to claim 10, characterized in that the metal dispersion layer deposited without external current is a copper, nickel or gold layer with embedded non-metallic particles.

13. Object according to claim 12, characterized in that the non-metallic particles have a hardness of more than 1,500 HV and are selected from the group of silicon carbide, corundum, diamond and tetraborarbide.

14. Article according to claim 12 or 13, characterized in that the non-metallic particles have friction-reducing properties and selected from the group of polytetrafluoroethylene, molybdenum sulfide, cubic boron nitride and tin sulfide.

15. Object according to one of the preceding claims, characterized in that a layer of aluminum, titanium or their alloys is applied to the metal layer deposited without external current, the surface of which is anodically oxidized or ceramized.

16. Object according to claim 15, characterized in that one or more metallic layers are arranged between the metal layer deposited without external current and the layer of aluminum, titanium or their alloys.

17. The article according to claim 15 or 16, characterized in that the surface of the article is a black colored ceramic oxide layer made of aluminum, titanium or their alloys due to the inclusion of foreign ions.

18. A method for producing an article according to one of the preceding claims, comprising the following steps: i. the surface of the non-metallic layer is not chemically pretreated before the metal layer deposited without external current is applied; ii. the surface of the non-metallic layer is microstructured in a first step by means of a blasting agent; iii. the metallic layer is then applied by electroless metal deposition.

19. Use of an object according to one of claims 1 to 17 as a roller for the web processing industry (foils, paper, textiles, printers), component of turbomolecular pumps (ring for the compressor stage), handle for household appliances (pots, lids), Component for the aerospace industry (handle, handrail) and the aerospace industry (sun sail), component for the electronics industry (capacitor, sound field capacitor, sound tab, microwave waveguide, switch surface, antenna, antenna housing), component for the moving components of cyclones, air classifiers, mechanical, thermal and / or chemically stressed component for the Automotive industry (brake pistons for automobiles) or as a mold or component for the injection molding industry.