Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/54—Electroplating of non-metallic surfaces
  • C25D5/56—Electroplating of non-metallic surfaces of plastics
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/60—Electroplating characterised by the structure or texture of the layers
  • C25D5/605—Surface topography of the layers, e.g. rough, dendritic or nodular layers
  • C25D5/611—Smooth layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/10—Electroplating with more than one layer of the same or of different metals
  • C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
  • C25D5/14—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium two or more layers being of nickel or chromium, e.g. duplex or triplex layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/34—Pretreatment of metallic surfaces to be electroplated
  • C25D5/38—Pretreatment of metallic surfaces to be electroplated of refractory metals or nickel
  • C25D5/40—Nickel; Chromium
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/48—After-treatment of electroplated surfaces
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/60—Electroplating characterised by the structure or texture of the layers
  • C25D5/605—Surface topography of the layers, e.g. rough, dendritic or nodular layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/627—Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
  • C25F5/00—Electrolytic stripping of metallic layers or coatings

Definitions

• the present invention relates to a method for producing a metal surface on a component which is to have a matted appearance.
• Metallic surfaces are desired for many components and are adapted in many ways to the particular technical and aesthetic requirements. This relates to the metallization of already metallic base body but also the metallization of non-metallic components, especially those made of plastic materials. A preferred application in the present context relates to vehicle parts, especially vehicle interior parts and in particular trim parts of a car, especially inside.
• the present invention is based on the problem to provide an economical method for producing a metal surface.
• a basic idea of the invention is to make an already chrome-plated workpiece the starting point of the method.
• This chrome-plated part is chromium-plated, wet-chemically and oxidatively (in particular anodically), ie by converting the chromium into chromium oxides or chromates. It has been found that in many applications by standard methods chrome-plated workpieces can be obtained at very low cost, because they are produced on an industrial scale and in very large quantities. These workpieces are well protected by chrome plating and easy to transport. They can then be dechromed again for more individualized metallization so that the base metallization underlying the removed chromium layer is available e.g. B. a nickel surface.
• the ingredient mainly responsible for the acid of the bath is hydrochloric acid, and preferably, the nickel is present in this bath as chloride.
• the process may conveniently take place at about room temperature, that is, for example, in a temperature range of 10 to 45 ° C, preferably 15 to 40 ° C or 15 to 35 or 30 ° C.
• the preferred layer thickness is 0.5 ⁇ m to 3 ⁇ m, preferably up to 2 ⁇ m.
• This nickel interlayer forms a reliable and with regard to the subsequently desired and to be adjusted gloss or matte as well as very advantageous basis for adhesion.
• metallization which may be, for example, and preferably again a nickel layer, in particular a Watt's nickel layer, which is typically deposited at a higher pH, on the order of pH 4. It can be made from baths with nickel sulfate and also chloride, buffered with boric acid, are deposited.
• the Schickher the matte layer should be comparatively low and can be between 1 and 20 microns, with upper limits of 19 microns, 18 microns, 17 microns, 16 microns and more preferably 15 microns and lower limits of 2 microns, 3 microns, 4 microns and more preferably 5 microns are even cheaper.
• the layer thickness is also determined by optical / aesthetic considerations.
• a shiny metallization can be deposited, in particular a nickel layer again.
• Baths that are basically also suitable for the Wattsche nickel layer, but which contain glaze carriers as additives, some saccharin and wetting agent are considered here.
• a layer can restore the existing dullness to a certain luster and make the gloss level finely adjustable by virtue of its thickness. So it can, for example, depending on the aesthetic requirements or other criteria, a certain "semi-gloss" set.
• a favorable thickness for this nickel layer is in the range of 5 and 25 microns, with a lower limit of 10 and an upper limit of 20 microns and 15 microns are more preferred.
• a protective topcoat is preferred. If the metallic nickel color is of interest, a clearcoat can also be used here.
• a particular advantage is that can be adjusted by galvanic parameters in a very simple manner, the degree of gloss or matte degree.
• Different optical properties can be generated with one and the same basic process, that is, the same solution compositions, identical baths, etc.
• this or other metal layer may be mechanically ground to the desired aesthetic image (or other purposes) on the basis discussed (prior to application of the topcoat layer).
• the mechanical grinding may be on a part of the surface and other aesthetic (or other) specifications may be observed in another part, for example the adjustable gloss or adjustable dullness just mentioned.
• this additional metal layer is not intended to completely level the matted structure, but at least to a substantial extent.
• metallization processes tend more or less to flatten roughnesses underneath.
• the smoothing or leveling to a certain extent may well be desired, so you can also use the leveling effect as a design tool. Accordingly, the layer is to be set thicker or to choose the material of the upper metal layer.
• the materials below and above the ground surface may differ.
• the appearance of metal color may be determined by the upper metal layer, although it may be less suitable for grinding. Grinding offers a known and proven way of matting the surface with roughness and line geometry that can be set in relatively wide limits in comparison to chemical processes. For example, during grinding, certain types of grinding movements and certain gradations of the abrasive may be selected.
• abrasives are used which contain abrasive particles, that is to say, in particular, abrasive pastes, particle-coated abrasive papers or abrasive cloths, and, in a particularly preferred manner, bonded abrasive particles in nonwovens or brushes with bristles occupied by corresponding particles.
• abrasives without abrasive particles that is, in particular conventional brushes, for example with metal bristles. They may, the inventors have found, pose cleaning problems and tend to smear.
• a preferred size range for the abrasive particles is between 10 .mu.m and 200 .mu.m, the lower limits increasingly being preferred are 20 .mu.m, 30 .mu.m and 35 .mu.m, and the upper limits increasingly preferred are 150 .mu.m, 100 .mu.m, 80 .mu.m, 60 .mu.m and 50 .mu.m. These ranges refer to averages.
• a particular advantage of matting with mechanical grinding is the possibility of a substantially uniform line direction, so to speak a "brushed" appearance. For this just uniform movements of the abrasive or a rotation of the same to achieve a straight movement along the surface to be ground to perform.
• a suitable thickness for the metal layer to be ground can be, for example, at least 5 ⁇ m, preferably at least 10 ⁇ m.
• the metal layer above can contain a metal selected from the group consisting of chromium, silver, gold, copper, one of the platinum metals and nickel as the main constituent or (in the technical sense) exclusively. But it could be used combinations thereof. Particularly preferred are silver, gold, the platinum metals and especially chromium. In principle, and especially in the case of not entirely unproblematic surfaces such as nickel, the metal layer may additionally be coated, preferably transparent for the preservation of the appearance. Uncoated metal layers are preferred. A suitable thickness for the metal layer on the ground surface may, for example, be between 0.1 and 3 ⁇ m. To improve a layer of z. B. 1 - 5 microns "semi-gloss" nickel can be applied to the ground surface.
• a commercially available and chromed car interior trim part is procured and anodically removed from the chromium plating in a known strongly oxidizing dechroming.
• the resulting base surface may already be a nickel surface (passivated as a result of the dechroming).
• This surface is according to the invention in a very acidic nickel chloride bath with hydrochloric acid to adjust a pH of just below 1 relatively thin nickel, z. B. for 15 minutes at room temperature, ie about 18 to 20 ° C, at a typical current density of 0.5 A / dm 2 , which gives an approximate layer thickness of 0.5 - 1 micron.
• This layer provides an excellent base for a per se known Watt's nickel plating at a pH (boric acid buffering) of about 4, for which a nickel sulphate bath is used, without brightener additives. This is carried out at a current density of about 0.5 A / dm 2 from an aqueous solution containing 210 g / l nickel sulfate, 35 g / l nickel chloride and 40 g / l boric acid without further additives.
• the layer thickness range is between 5 and 15 .mu.m, whereby the mattness of the layer ultimately resulting is adjusted via the layer thickness.
• This Wattsche nickel layer is then coated in need to reduce their own dullness with a so-called semi-bright nickel layer, in the z.
• B. saccharin as a glossy carrier and wetting agent are added to the otherwise unchanged bath (the nickel plating Vernickelung).
• this semi-bright nickel layer there is often a silk mattness or a limited gloss given off for aesthetic reasons.
• This nickel surface is then mechanically ground.
• commercially available skew products which contain plastic-bonded abrasive articles in a nonwoven. Exemplary may be the so-called Scotch-Brite products of the manufacturer 3M.
• the nonwoven fibers form an elastic nonwoven base structure, wherein the abrasive bodies are incorporated in the nonwoven by a resin bond.
• abrasive products are available in different packaging.
• flat products are suitable in the manner of a lobe; but it can also be done by machine with belts or rotating cylinders.
• a thin "semi-gloss" nickel layer and then a topcoat are applied first.
• this is a conventional gloss chromium layer of thickness 1 micron.
• the Schlötter-Bad slotochrome GC10 with hexavalent chromium or slotochrome 50 with trivalent chromium into consideration.
• the total layer is well protected against environmental influences and resistant to oxidation. It ultimately shows an adjustable metallic chrome gloss.

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Citations (4)

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• 2015
  • 2015-11-23 EP EP15020234.9A patent/EP3170925B1/fr not_active Not-in-force
  • 2015-11-23 EP EP19193418.1A patent/EP3604623A1/fr not_active Withdrawn
• 2016
  • 2016-11-10 WO PCT/EP2016/025140 patent/WO2017088982A1/fr active Application Filing

Patent Citations (4)

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