EP0217126B1 - Galvanic hard chromium layer - Google Patents

Galvanic hard chromium layer Download PDF

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Publication number
EP0217126B1
EP0217126B1 EP19860111775 EP86111775A EP0217126B1 EP 0217126 B1 EP0217126 B1 EP 0217126B1 EP 19860111775 EP19860111775 EP 19860111775 EP 86111775 A EP86111775 A EP 86111775A EP 0217126 B1 EP0217126 B1 EP 0217126B1
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EP
European Patent Office
Prior art keywords
cracks
chromium layer
characterized
hard chromium
layer according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19860111775
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German (de)
French (fr)
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EP0217126A1 (en
Inventor
Rudolf Linde
Ulrich Dipl.-Ing. Buran
Hans-Jochem Dr. Neuhäuser
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Goetze GmbH
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Goetze GmbH
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Publication date
Priority to DE3531410 priority Critical
Priority to DE19853531410 priority patent/DE3531410C2/de
Application filed by Goetze GmbH filed Critical Goetze GmbH
Publication of EP0217126A1 publication Critical patent/EP0217126A1/en
Application granted granted Critical
Publication of EP0217126B1 publication Critical patent/EP0217126B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D15/00Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires
    • C25D15/02Combined electrolytic and electrophoretic processes with charged materials

Description

  • The invention relates to a galvanic hard chrome layer with a crack network extending through the entire layer thickness and its production method.
  • Electroplated hard chrome layers have above all a high hardness and associated high wear resistance, a strong surface smoothness and associated low coefficient of friction and low adhesive power as well as a good resistance to aggressive chemical, corrosive, erosive and oxidative stress at possibly higher temperatures. For this reason, the treads of machine parts, such as the treads of piston rings or cylinders in internal combustion engines, are coated with hard chrome layers in order to achieve special wear resistance.Pressing tools and molds for the production of plastic molded articles are provided with chrome layers or are used to achieve special smoothness and wear resistance For better durability, valve parts are especially protected by chrome layers in chemical plants.
  • With electroplated chrome deposition, relatively high tensile stresses occur in the chrome layers, which, when a certain layer thickness is reached by exceeding the elasticity of the chromium, which is only slightly elastic, lead to microcracks, which appear in the etched surface micrograph in the form of a spider-woven network of fine lines and cracks. In the case of oil-lubricated wear protection layers as oil grooves or or oil wells, such micro-crack nets facilitate the wettability of the chrome layers with oil and thus the formation of the oil film required for the lubrication, so that in this case during or after the chrome plating by selection of suitable chrome plating parameters, by periodic current reversal, by thermal aftertreatment or the chrome crack network is expanded by etching to form a porous chrome layer. Above all, however, corrosion-protecting chrome layers should be as free from cracks as possible, and a chrome plating process is then chosen in which the chrome layers have at most a micro-crack network.
  • Hard chrome layers are also not very elastic and brittle. Especially in the case of shock loads and strong vibrations, breaks can occur in the layers, which then lead to the layers flaking off.
  • In order to improve the physical properties of electrodeposited metal layers, it is known to incorporate finely dispersed solid particles into the matrix metal by performing the metal deposition from a galvanic bath with solid particles finely dispersed therein. Nickel dispersion layers with embedded hard material particles, especially silicon carbide, have an improved wear behavior and nickel dispersion layers with embedded solid lubricant particles have a lower coefficient of friction. While the production of galvanic nickel dispersion layers is relatively unproblematic, chromium dispersion layers cannot be easily produced and galvanic chromium dispersion layers with correspondingly improved properties are not used in practice. Obviously due to the increased hydrogen evolution on the chromium during the galvanization, dispersed solid particles are prevented from being deposited in the chromium layer. For this reason, hard chrome layers with finely dispersed solid particles have to be produced relatively expensively by preferably plasma spraying processes.
  • The present invention is therefore based on the object of providing a hard chrome layer with improved physical and technological properties in which, above all, the disadvantages indicated are eliminated. At the same time, the aim is to find a galvanic process which can be used as universally as possible and with which layers of this type can be produced simply and cost-effectively.
  • According to the invention, this object is achieved by a hard chrome layer. solid particles are embedded in the cracks. In this case, the gap width of the cracks should preferably be over 0.5 μm, but in particular over 11 μm, so that solid particles can be deposited at all, and the preferred thickness of the hard chrome layer is between 10 μm and 1,000 μm. The invention thus creates a hard chrome layer, in the crack network of which solid particles are embedded, which improve the properties of the hard chrome layer in the desired manner, particularly in the case of a high crack density, in accordance with their properties, such as in the case of a galvanic dispersion layer.
  • Accordingly, the substances used in the production of galvanic dispersion layers are suitable as solid particles, individually or in combination, but they must not dissolve in the microcracking chromic acid baths, their grain size must be below the gap width of the chromium cracks, i.e. preferably between about 0.5 and 15 μm and the thickness of the chrome layer should be several times larger than the grain size of the particles.
  • Solid particles made primarily of aluminum oxide, boron carbide, boron nitride, chromium carbide, silicon dioxide, titanium carbide, diamond and / or tungsten carbide are suitable as solid particles for improving wear resistance. Such chromium layers containing solids are then particularly suitable for coating the tread of piston rings or cylinder liners in internal combustion engines. The solid lubricant particles used consist of hexagonal boron nitride, graphite and / or polymer particles, especially of polyvinyl chloride and / or polytetrafluoroethylene, and for improvement ductility or reduction in brittleness, ductile metals or metal alloys made of tin, titanium or bronze can be embedded in the cracks. The tendency of chrome to adhesive wear can also be reduced by embedded molybdenum particles.
  • However, it was also found that the color of the chrome layers according to the invention can be influenced by organic dyes or colored metal salts embedded in the cracks. It was also found that filling the cracks with solid particles increased the corrosion resistance of the layers. For this purpose, the cracks were preferably filled with polyvinyl chloride particles, and the polyvinyl chloride was then melted into the cracks, so that the cracks were sealed and protected against corrosive attacks.
  • For the purposes of the invention, solid particles of one or more types of substance can be used in combination to fill the cracks, so that several physical properties are improved at the same time. Likewise, the cracks need not be completely filled with the solid particles. In the sense of the invention, it is also possible to fill the cracks in the individual layer layers with different types of solid lubricants. For example, cracks in the chrome layer zones directly on the substrate can be filled with a corrosion-preventing substance, while the cracks in the outer chrome layer zones are filled with wear particles or sliding substances or are even particle-free, so that corrosion-protected layers with good wear and sliding properties are created. Likewise, the outermost zones can additionally be filled with a substance that promotes enema, such as elemental tin or iron oxide.
  • In order to produce the chromium layers according to the invention, well-known chromium-cracking chromium plating baths, such as preferably acidic chromic acid baths, with solid particles dispersed therein are used. During the chrome plating, the workpiece to be chrome plated is first switched cathodically, so that a micro-cracked chrome layer forms, then the workpiece is switched anodically, so that the micro-cracks widen to the desired gap width and the cracks fill with the solid particles and then again occurs a cathodic circuit so that the solid particles are encapsulated and sealed by closing the cracks. This periodic current reversal can, if necessary, be repeated several times, the person skilled in the art being able to vary the chromium plating parameters in accordance with the application in such a way that the desired crack width, crack density and crack filling are produced with, if necessary, different solid particle fillings.
  • Hard chrome layers are thus created by the invention, the physical and technological properties of which are significantly improved by solid particles embedded in the cracks. The chrome layers can above all, as shown, have improved wear behavior, better sliding properties, better running-in behavior, better fire trace safety, better protection against fractures and flaking and better corrosion behavior individually or in combination. For the purposes of the invention, all known chromic acid-insoluble solid particles can be used to fill the cracks.
  • The process according to the invention for producing the chromium layers is relatively simple to carry out and allows the person skilled in the art to produce the desired properties universally by varying the chromium plating parameters and adapted to the application.
  • The invention is illustrated by the exemplary embodiments and the micrographs.
  • The starting point is a micro-cracking chromium plating electrolyte
    • 250 g / l chromic acid and
    • 2.5 g / l sulfuric acid,
  • in which 50 g / l of solid particles with a particle size between 0.5 and 5 pm are dispersed by stirring and kept in suspension during the chrome plating.
  • The chrome plating takes place for a total of about 5 hours at 55 ° C. with the formation of a chrome layer with a total thickness of 0.2 mm.
  • For chrome plating, a test rod (diameter 12 mm) 5 cm long and 5 cm wide is first cathodically chromium-plated at 65 A / dM2 for 30 minutes and then the layer is anodically etched by anodically switching the test rod for 30 sec with a current density of 150 A. / dm 2 . This periodic chrome plating takes place in a total of 10 stages, the chrome plating and etching taking place under the same process parameters.
  • In test trials, the production of
    • a) Wear layers of silicon carbide particles used.
    • b) Sliding layers with improved run-in behavior were produced with hexagonal boron nitride particles.
    • c) Polyvinyl chloride particles were used to produce layers with improved corrosion behavior, the polymer in the finished layer being heated at 80 ° C. for 10 minutes to melt.
    • d) lead chromate particles were used to produce yellow layers.
  • Improved technological and physical properties were found in the test strips produced.
  • The three micrographs show scanning electron micrographs of the hard chrome layers according to the invention according to the exemplary embodiment.
    • FIG. 1 is a surface micrograph in a magnification of a thousand times,
    • FIG. 2 shows a cross section in a magnification of a thousand times,
    • Figure 3 is an oblique section image in four thousand times magnification.
  • The cracks extending through the chrome layer in the manner of a cobweb can be seen in FIG. The silicon carbide particles embedded in the cracks can be recognized as bright particles.
  • The cross section of FIG. 2 shows the cross sections of the cracks, which extend approximately at right angles to the surface. The cracks are closed by the periodic reversal of the current during chrome plating by means of chromium layers formed over them, so that the embedded bright silicon dioxide particles are encapsulated in the cracks.
  • In the oblique section of FIG. 3, at a magnification of four thousand times, it can be seen how the silicon carbide particles in the cracks are partially covered and anchored by subsequently deposited chromium.

Claims (17)

1. Electroplated hard chromium layer with a network of cracks extending through the whole thickness of the layer, characterized in that solid particles are embedded in the cracks.
2. Hard chromium layer according to claim 1, characterized in that the thickness of the hard chromium layer lies between 0,01 and 1,0 mm.
3. Hard chromium layer according to one of claims 1 and 2, characterized in that the width of the cracks is greater than 0,001 mm.
4. Hard chromium layer according to one of claims 1 to 3, characterized in that the grain size of the embedded solid particles lies between 0,0005 and 0,015 mm.
5. Hard chromium layer according to at least one of claims 1 to 4, characterized in that hard material particles are embedded in the cracks as solid particles, in order to enhance the resistance to wear.
6. Hard chromium layer according to claim 5, characterized in that the hard material particles consist of tungsten carbide, chromium carbide, aluminium oxide, silicon carbide, silicon nitride, boron carbide and/or diamond.
7. Hard chromium layer according to at least one of claims 1 to 4, characterized in that solid lubricant particles are embedded in the cracks as solid particles, in order to enhance the sliding characteristics.
8. Hard chromium layer according to claim 7, characterized in that the solid lubricant particles consists of graphite, hexagonal boron nitride and/or polytetrafluoroethylene.
9. Hard chromium layer according to at least one of claims 1 to 4, characterized in that ductile metals and/or metal alloys are embedded in the cracks as solid particles, in order to enhance the ductility.
10. Hard chromium layer according to claim 9, characterized in that the ductile metals and/or metal alloys consist of titanium, tin and/or bronze.
11. Hard chromium layer according to at least one of claims 1 to 4, characterized in that thermoplastic polymers are embedded in the cracks as solid particles, in order to enhance the resistance to corrosion, and in that the thermoplastics are fused after the embedding in the cracks.
12. Hard chromium layer according to at least of claims 1 to 4, characterized in that the organic and/or inorganic dyestuffs are embedded in the cracks as solid particles.
13. Hard chromium layer according to at least one of claims 1 to 4, characterized in that there are embedded in the cracks as solid particles mixtures of at least two components of hard material particles, solid lubricant particles, metals, metal alloys, organic thermoplastics and/or organic and inorganic dyestuffs.
14. Hard chromium layer according to at least one of claims 1 to 13, characterized in that the chromium layer consists of a plurality of chromium layers, in the cracks of which different solids or solid mixtures are embedded.
15. Hard chromium layer according to at least one of claims 1 to 14, characterized in that the cracks of the individual chromium layer sites are filled with solid particles to different degrees.
16. Method of making the hard chromium layers according to at least one of claims 1 to 15, characterized in that the chromium plating takes place in a chromium plating electrolyte known per se which forms micro-cracks, in which the solid particles are dispersed, and in that the workpiece is alternately switched cathodically and anodically by one or multiple periodic reversals of current, so that the chromium layer forms on the workpiece during the cathodic connection and the micro-cracks widen and fill with the solid particles during the anodic connection, whereby the cracks are closed and the solid particles are encapsulated in the cracks during the following cathodic connection.
17. Method according to claim 16, characterized in that the time of the cathodic connection is several times greater than the time of the anodic connection.
EP19860111775 1985-09-03 1986-08-26 Galvanic hard chromium layer Expired - Lifetime EP0217126B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE3531410 1985-09-03
DE19853531410 DE3531410C2 (en) 1985-09-03 1985-09-03

Publications (2)

Publication Number Publication Date
EP0217126A1 EP0217126A1 (en) 1987-04-08
EP0217126B1 true EP0217126B1 (en) 1990-07-04

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EP19860111775 Expired - Lifetime EP0217126B1 (en) 1985-09-03 1986-08-26 Galvanic hard chromium layer

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US (1) US4846940A (en)
EP (1) EP0217126B1 (en)
JP (1) JP2602499B2 (en)
BR (1) BR8604205A (en)
DE (1) DE3531410C2 (en)
ES (1) ES2001645A6 (en)
HK (1) HK115395A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
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DE19752720A1 (en) * 1997-11-28 1999-06-10 Federal Mogul Burscheid Gmbh Process for producing an oil scraper ring
DE10121593A1 (en) * 2001-05-03 2002-11-07 Duralloy Ag Haerkingen Process for coating workpieces with a bearing metal
DE102007038188A1 (en) 2007-08-13 2009-02-19 Federal-Mogul Burscheid Gmbh Coated machine element e.g. piston ring with a surface useful in internal combustion engine, comprises a structured hard chrome layer, a physical vapor deposition- or a chemical vapor deposition layer, and a chromium-solid particle layer

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GB9103481D0 (en) * 1991-02-20 1991-04-10 T & N Technology Ltd Bearings
US5770323A (en) * 1991-02-20 1998-06-23 T & N Technology Limited Bearings
US5614320A (en) * 1991-07-17 1997-03-25 Beane; Alan F. Particles having engineered properties
US5453293A (en) * 1991-07-17 1995-09-26 Beane; Alan F. Methods of manufacturing coated particles having desired values of intrinsic properties and methods of applying the coated particles to objects
IT1267394B1 (en) * 1994-02-18 1997-02-05 Ind S R L Process for the production of composite overs galvanic hard chromium plating with a dispersed phase and anti-wear coating made with
US5490445A (en) * 1994-03-14 1996-02-13 Ford Motor Company Ultra low device volume piston system
FR2726289B1 (en) 1994-10-28 1997-03-28 Floquet Monopole Method for electrodeposition of a chrome coating having solid inclusions and bath implemented in this process
DE19529843A1 (en) * 1995-08-12 1997-02-13 Marco Santini Galvanic chrome plating process
US6054225A (en) * 1996-11-11 2000-04-25 Teikoku Piston Ring Co., Ltd. Composite chromium plating film and sliding member covered thereof
EP0841413B1 (en) * 1996-11-11 2001-09-26 Teikoku Piston Ring Co., LTd. Composite chromium plating film and sliding member covered thereof
DE19745811C2 (en) * 1997-10-16 2002-06-13 Federal Mogul Burscheid Gmbh Electroplated hard chrome layer, use and method for the production thereof
US6039860A (en) * 1998-11-09 2000-03-21 Mcdonnell Douglas Corporation Method for chromium plating titanium alloy
EP1006218B1 (en) * 1998-12-03 2006-03-08 Yamaha Hatsudoki Kabushiki Kaisha Plated disc brake and method of manufacturing same
SE514700C2 (en) * 1999-03-19 2001-04-02 Daros Holding Ab Electrolytic coating a substrate with a ceramic chrome layer, ceramic chrome layer and piston ring
DE19931829A1 (en) 1999-07-08 2001-01-18 Federal Mogul Burscheid Gmbh Galvanic hard chrome layer
EP1253220A4 (en) * 1999-12-27 2006-03-22 Nippon Piston Ring Co Ltd Sliding member
AT408351B (en) * 2000-05-17 2001-11-26 Miba Gleitlager Ag Method for galvanically depositing a dispersion layer on a surface of a workpiece
JP4059621B2 (en) * 2000-09-29 2008-03-12 日本ピストンリング株式会社 Chromium plating sliding member and manufacturing method thereof
JP4068879B2 (en) * 2001-08-21 2008-03-26 株式会社神戸製鋼所 Metal parts with excellent antibacterial and / or algal resistance
DE10255853A1 (en) 2002-11-29 2004-06-17 Federal-Mogul Burscheid Gmbh Manufacture of structured hard chrome layers
US7318963B2 (en) 2004-01-30 2008-01-15 Kabushiki Kaisha Riken Composite chromium plating film and sliding member having the same and method for manufacture thereof
DE102004019370B3 (en) 2004-04-21 2005-09-01 Federal-Mogul Burscheid Gmbh Production of optionally coated structurized hard chrome layer, used e.g. for decoration, protection or functional coating on printing roller or stamping, embossing or deep drawing tool uses aliphatic sulfonic acid in acid plating bath
CN100359048C (en) * 2004-12-27 2008-01-02 西安建筑科技大学 Conductor roll restoring method
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US7383807B2 (en) * 2005-05-23 2008-06-10 Federal-Mogul World Wide, Inc. Coated power cylinder components for diesel engines
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DE102007037778A1 (en) * 2007-08-10 2009-02-12 Mahle International Gmbh Hard chrome layer, coated substrate and tribological system
DE102008017270B3 (en) 2008-04-04 2009-06-04 Federal-Mogul Burscheid Gmbh Structured chromium solid particle layer and method for its production and coated machine element
CN103403229B (en) * 2010-12-27 2016-05-25 日本活塞环株式会社 Composite chrome plating overlay film and use the slide unit of this overlay film
DE102011084052A1 (en) 2011-10-05 2013-04-11 Federal-Mogul Burscheid Gmbh Coated piston ring for use in combustion engine such as reciprocating piston engine, has base body whose outer circumferential surface and flank surface form outer edge, which exhibits ridge or ablation having specific range width
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DE102012204156A1 (en) 2012-03-16 2013-09-19 Federal-Mogul Burscheid Gmbh Piston ring with chrome solid particle wear protection layer and corrosion resistant flank surface
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JP6569178B2 (en) * 2015-10-08 2019-09-04 地方独立行政法人大阪産業技術研究所 Article having composite hard coating and method for producing the same
US9945481B2 (en) 2016-07-07 2018-04-17 Federal-Mogul Llc Polymer coating in cracked piston ring coating
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19752720A1 (en) * 1997-11-28 1999-06-10 Federal Mogul Burscheid Gmbh Process for producing an oil scraper ring
DE19752720C2 (en) * 1997-11-28 2000-07-06 Federal Mogul Burscheid Gmbh Process for producing an oil scraper ring
DE10121593A1 (en) * 2001-05-03 2002-11-07 Duralloy Ag Haerkingen Process for coating workpieces with a bearing metal
US6875330B2 (en) 2001-05-03 2005-04-05 Duralloy Ag Process for coating workpieces with bearing metal
DE102007038188A1 (en) 2007-08-13 2009-02-19 Federal-Mogul Burscheid Gmbh Coated machine element e.g. piston ring with a surface useful in internal combustion engine, comprises a structured hard chrome layer, a physical vapor deposition- or a chemical vapor deposition layer, and a chromium-solid particle layer

Also Published As

Publication number Publication date
EP0217126A1 (en) 1987-04-08
BR8604205A (en) 1987-04-28
US4846940A (en) 1989-07-11
HK115395A (en) 1995-07-21
JPS6256600A (en) 1987-03-12
ES2001645A6 (en) 1988-06-01
JP2602499B2 (en) 1997-04-23
DE3531410A1 (en) 1987-03-05
DE3531410C2 (en) 1989-03-23

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