Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F3/00—Pistons 
  • F02F3/10—Pistons  having surface coverings
• • 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
  • C25D5/42—Pretreatment of metallic surfaces to be electroplated of light metals
  • C25D5/44—Aluminium
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D7/00—Electroplating characterised by the article coated
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/20—Electroplating: Baths therefor from solutions of iron
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
  • F05C2201/00—Metals
  • F05C2201/02—Light metals
  • F05C2201/021—Aluminium
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
  • F05C2201/00—Metals
  • F05C2201/04—Heavy metals
  • F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
  • F05C2201/0436—Iron
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
  • F05C2201/00—Metals
  • F05C2201/90—Alloys not otherwise provided for
  • F05C2201/903—Aluminium alloy, e.g. AlCuMgPb F34,37
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
  • F05C2253/00—Other material characteristics; Treatment of material
  • F05C2253/12—Coating

Definitions

• Process for applying electrodeposited metal coatings to components made of aluminum or an aluminum alloy, in which the surface of the component is cleaned in a suitable solution, in particular oils, greases, emulsions, pigments, etc., and that the surface is then etched in a suitable solution is so that a certain amount of the material or the near-surface alloy components are dissolved and that after cleaning and after dissolving, rinsing with water takes place.
• Measures to increase wear resistance include alloying, tempering and coating. Coating in particular plays an important role in aluminum materials and their alloys, because this enables the positive properties of these materials to be combined with those of the coating.
• a functional layer can consist of iron, for example, and is used for wear resistance, among other things.
• DE 19 15 762 discloses a method for applying electrodeposited metal coatings on aluminum and aluminum alloys.
• the surface of the material is cleaned, then activated and provided with an adhesive intermediate layer and then plated with a coating material, in this case the coating would be the functional layer.
• the intermediate layers used here can consist of zinc, nickel, tin or copper.
• the parts to be metallized are immersed in a solution consisting of hydrochloric acid, copper (II) chloride and a metallic copper powder after the cleaning and activation process until an intermediate layer of monovalent copper has formed on the surface of the aluminum in this immersion bath.
• a disadvantage of this method is the high aggressiveness of the chloride electrolyte, so that the use of this method is expensive and with great effort, for. B. is related to occupational safety.
• the further development of the process is aimed at replacing cyanide zincate stains with cyanide-free ones. This is done by using organic complexing agents instead of cyanide and iron instead of nickel and copper.
• a special complexing agent system was developed for the cyanide-free zincate stain.
• the metal ions are complexed exactly so that there is a uniform and controlled deposition with excellent adhesion.
• the complexing agent enables rapid ion exchange and thus ensures rapid layer build-up.
• the article does not provide any indication that an intermediate layer can be completely dispensed with for the deposition of a functional layer, described below using the example of a nickel layer.
• the article also does not show that it is possible to directly deposit iron layers on the aluminum surface.
• the idea according to the invention achieves the object in that the surface of the component is activated immediately after the dissolving of the areas near the surface in a solution containing iron ions based on sulfate by anodic switching of the component and that without intermediate rinsing in the same, in the same or in an equivalent electrolyte by cathodic switching of the Component the functional layer is applied and that the functional layer consists of iron.
• the components are cleaned and freed from troublesome fats, oils, emulsions, pigments and similar impurities in the manufacturing process. After cleaning, rinse thoroughly with water.
• the surface of the components is then etched in a suitable solution, i. H. a certain amount of aluminum or alloy components close to the surface is dissolved. Then the component is again thoroughly rinsed with water.
• the deposition of an intermediate layer does not follow, but the component is introduced directly into a sulfate-based electrolyte.
• the electrolytes usually used work on the basis of chloride, fluoroborate or ammonium sulfate. As described above, chloride electrolytes have a high level of aggressiveness, the fluoroborates have a high level of aggressiveness and toxicity, and the ammonium sulfate electrolytes have poor wastewater compatibility.
• the invention is advantageously based on a sulfate-based electrolyte which is neither aggressive, nor toxic, nor harmful to waste water.
• the surface in the electrolyte is first activated by anodic switching of the component. The activation takes place, for example, in a solution with the following
• Process parameters in a solution with 300 g / 1 iron II sulfate heptahydrate (FeSO4 * 7H2O), at a temperature of 70 ° C, with a pH of 2, an activation current density of 2 A / dm 2 and a treatment time of 20 seconds.
• the component without intermediate rinsing by cathodic switching of the component, using an iron electrolyte based on sulfate
• Example 1 hard materials with a size of 0.5 to 2.0 ⁇ m are added to the electrolyte.
• hard materials z.
• Chromium nitride, titanium carbide, cubic boron nitride as well as diamond particles can be used.
• the invention relates not only to these hard materials, but also includes all solids made from oxides or oxide ceramics, carbides and
• Nitrides with a These hard materials are mainly used individually, but can also be used as a mixture or mixtures.
• an iron layer is formed, which contains about 15% by weight of the hard materials in finely divided form. The most secluded
• Functional layer had excellent wear properties and had a hardness of approx. 400 HV 0.05.
• solid lubricants were added to the electrolyte, which were approximately 0.2 to 2.0 ⁇ m in size.
• Solid lubricants here include hexagonal boron nitride, carbon fluoride, graphite, molybdenum sulfide, Teflon, steel particles or microcapsules filled with oil. These solid lubricants can be used separately but also as a mixture or mixtures. The tests have shown that the solid lubricants have an extremely positive influence on the tribological system and that the friction coefficients were more favorable. A functional layer formed in which the solid lubricants were finely divided and were present with a share of approximately 20% by volume.
• solid lubricants and hard substances can be contained together in the electrolyte, so that the positive properties of these two substances can be combined.
• an iron layer or functional layer separates, in which the two substances are finely divided and dispersive.
• the hardness of this layer was 350 HV 0.05.
• a sulfate-based electrolyte according to the invention containing 300 g / 1 iron II sulfate heptahydrate was used in a proportion of 5 ml / 1 of a hypophosphorous acid, e.g. B. H3PO2 added.
• the functional layer formed by the method according to the invention then had a hardness of 700 HV 0.05. With the help of proportions of phosphorus in the electrolyte, it is thus possible to influence the hardness of the layer in a targeted manner.
• Example 5 a hard material according to Example 1 was added to the phosphorus-containing electrolyte from Example 4.
• the hardness of the layer produced was 750 HV 0.05, which means that the hardness could be increased even further.
• the wear tests showed values similar to those in Example 1.
• a solid lubricant according to example 2 was added to the phosphorus-containing electrolyte from example 4. Under these conditions, a functional layer separated out as an iron layer, in which about 20% by volume of solid lubricants were contained in finely divided form.
• the hardness of this layer was 650 HV 0.05.
• the results of the friction coefficient tests were better than those of the layers without phosphorus components. However, the results of the wear tests were comparable.
• the applied functional layers were characterized by an excellent bond to the base material of the component.
• a functional layer applied according to the examples of the invention as an iron layer, showed in an adhesion test under extreme conditions, e.g. B. thermal shock test, glass bead test and scratch test, an excellent bond to the base material and was comparable to the functional layers, which were applied with an adhesion-promoting intermediate layer based on zinc and copper and even superior in some areas.
• the functional layer has an excellent bond to the base material and at the same time serves as the basis for one or more layers.
• the coating materials are named in the subclaims, but they can only be seen as examples. Since the functional layer is primarily formed from iron, any layer material that has an affinity for iron can be applied to the component or to the functional layer. In particular, these are all metallic materials, but also plastics and ceramics.
• any method is suitable with which iron materials can also be coated.
• Electrochemical with the u. a. Tin, copper, etc. can be deposited, thermal, with which u. a. Molybdenum, etc., and reactive processes.
• u. a. high-speed flame spraying, plasma spraying, the PVD and CVD processes as well as screen printing processes or sprayed-on organic coatings.
• FIG. 1 shows the cross section through a component 1 coated according to the invention.
• the figure shows the base material 2 and the functional layer 3 applied thereon.
• the natural oxide layer on the base material 2 was removed and the components near the surface were dissolved, so that a clean surface 4 was available for coating.
• the functional layer 3 was directly deposited on this pure surface 4 by means of an electrolyte without an intermediate layer.
• the functional layer 3 consists primarily of iron 5, in which hard materials 6 and solid lubricants 7 are finely distributed.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Other Surface Treatments For Metallic Materials (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Electroplating Methods And Accessories (AREA)
• Chemical Treatment Of Metals (AREA)
• Electroplating And Plating Baths Therefor (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 2001
  • 2001-12-06 DE DE10159890A patent/DE10159890B4/de not_active Expired - Fee Related
• 2002
  • 2002-11-07 AU AU2002350675A patent/AU2002350675A1/en not_active Abandoned
  • 2002-11-07 ES ES02785370T patent/ES2264735T3/es not_active Expired - Lifetime
  • 2002-11-07 WO PCT/EP2002/012437 patent/WO2003048427A2/fr active IP Right Grant
  • 2002-11-07 EP EP02785370A patent/EP1451392B1/fr not_active Expired - Lifetime
  • 2002-11-07 BR BR0212923-0A patent/BR0212923A/pt not_active Application Discontinuation
  • 2002-11-07 JP JP2003549602A patent/JP2005511898A/ja active Pending
  • 2002-11-07 DE DE50207452T patent/DE50207452D1/de not_active Expired - Lifetime
  • 2002-11-07 PL PL368710A patent/PL204301B1/pl not_active IP Right Cessation
  • 2002-11-07 AT AT02785370T patent/ATE332401T1/de not_active IP Right Cessation
  • 2002-11-07 CN CN02823948.2A patent/CN1599809A/zh active Pending
  • 2002-11-07 US US10/497,580 patent/US20050067296A1/en not_active Abandoned

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