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
  • C25D5/34—Pretreatment of metallic surfaces to be electroplated
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
  • C23G1/22—Light metals
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/022—Anodisation on selected surface areas
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/026—Anodisation with spark discharge
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
  • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
  • C25D11/08—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing inorganic acids
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
  • C25D11/16—Pretreatment, e.g. desmutting
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
  • C25D11/18—After-treatment, e.g. pore-sealing
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D9/00—Electrolytic coating other than with metals
  • C25D9/04—Electrolytic coating other than with metals with inorganic materials
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D9/00—Electrolytic coating other than with metals
  • C25D9/04—Electrolytic coating other than with metals with inorganic materials
  • C25D9/06—Electrolytic coating other than with metals with inorganic materials by anodic processes
• • 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
  • F02F1/00—Cylinders; Cylinder heads 
  • F02F1/18—Other cylinders
  • F02F1/20—Other cylinders characterised by constructional features providing for lubrication

Definitions

• the invention relates to a method for producing a coated surface of a friction and wear-optimized cylinder liner and has previously been the background of increasing demands for a reduction of CO2 emissions in internal combustion engines of motor vehicles.
• NiSiC nickel-silicon carbide dispersion layer
• thermal coating methods are used (see, for example, DE 102007023297 A1 or US Pat. No. 5,691,004) in which the coating material is melted as an alloyed wire or as a heterogeneous powder and individual melt particles are thrown onto the cylinder wall at high speed and thus build up a thermal sprayed layer ,
• These layers are very expensive to produce and cause a high thermal load of the cylinder block.
• the cylinder block can warp, which is undesirable. Especially with weight-optimized and therefore thin-walled cylinders, this effect occurs.
• DE 195 06 656 A1 discloses a method for the ceramization of light metal surfaces using the spark discharge of electrolytes, in particular for the production of coatings of cylinder liners of internal combustion engines. Further, DE 195 06656 A1 discloses that the coating could be applied by a plasma-chemical process. In this case, reference is made to electrolyte compositions of DD 142 360. DE 195 06 656 A1 does not proceed to the plasma-chemical coating.
• the referenced DD 142 360 relates to a process for producing alpha-Al 2 O 3 -containing layers on aluminum metals and thus points only to a plasma-electrolytic oxidation of PEO.
• the object underlying the invention is to provide an economical and suitable for large-scale production process of aluminum workpieces, which leads to a wear-resistant surface; with good oil retention capacity.
• This object is achieved by a method comprising at least two process steps according to claim 1, which leads in the case of an aluminum cylinder block to a wear-resistant and friction-optimized topography of the cylinder bore.
• Starting point of the method according to the invention is a relatively coarse machined cylinder bore, which is present as a monolithic aluminum block or which is used as a wet or dry socket.
• the surface to be machined is in any case made of an aluminum alloy, usually of hypoeutectic aluminum.
• the pre-processing the surface is brought by honing or fine boring in the desired shape and processed to almost the final dimension.
• the (still) untreated aluminum can be machined very well and economically. It is possible to produce a cylindrical shape by the pre-machining.
• One suitable method is fine boring.
• this desired shape is only insignificantly changed. Since the electrolytically applied layer is very thin, a dimensional correction is virtually impossible. Therefore, almost the final dimension must be reached with the pre-processing.
• the pre-processing not only produces the desired shape, but also prepares the surface for the subsequent coating.
• the roughness achieved in the first process step has an influence on the final quality after coating.
• Roughnesses which lie in the range between 1-4 ⁇ Rz, have proved to be suitable.
• diamond grains from 010 to 046 were used in honing.
• the surface is still degreased before the coating is produced.
• the subsequently applied by electrolysis, ie by PED coating forms the pre-machined (nominal) form equidistant, so that the created by the first process step shape is largely retained.
• a wear-resistant coating is applied or produced by electrolysis, ie by PED.
• This layer has a high hardness and is therefore very resistant to wear.
• the porosity of the layer can be adjusted specifically. The porosity improves oil retention, reduces sliding friction wear and promotes hydrodynamic lubrication.
• the high hardness reduces the sliding friction in the mixed friction range at lower engine speeds and increases the service life.
• An electrolytic process according to the invention is the so-called “plasma electrolyte deposition", which is carried out in the aqueous electrolyte and effects both an inward edge change and a layer build-up to the outside.
• a further advantage of the PED is that, in addition to the layers of aluminum oxide mentioned, it is also possible to produce other metal oxide layers, so that according to the invention titanium oxide layers (.02) can be produced.
• a suitable method is known from US 7,578,921, B2.
• wear-resistant coatings which are obtainable by PED from an acidic aqueous electrolyte containing water-soluble compounds of the element titanium, preferably selected from fluorocomplexes, if the workpiece is predominantly connected as an anode. The workpiece is then predominantly connected as an anode if it has taken over a predominantly anodic amount of charge for all the time intervals during which the PED method is operated above the actual decomposition voltage of the electrolyte.
• Coatings produced in this way consist essentially of oxides / hydroxides of the element titanium and have proven to be particularly resistant to wear. The coatings produced in this way have an altered edge zone inwards with an invasion depth of z. B.
• the layer thicknesses typically used are well below 70 ⁇ , their hardness is up to 1500 HV.
• the hardness and topography of the coating can be adjusted via the electrical process parameters of the electrolysis.
• the coating process takes place in the electrolytic bath.
• the workpiece is largely masked, so that only the bore to be coated is in contact with the electrolyte and so a selective coating of the bore is possible.
• the masking is done, for example, with the aid of a lid, which - sealed with O-rings - closes the bore towards the crankcase.
• the electrode is preferably designed as a cylinder, which has approximately the length of the cylinder bore to be machined and is dimensioned such that a radial gap of about 20-30 mm thickness arises between the electrode and the cylinder bore. Through this gap the electrolyte flows with a volume flow of e.g. 20 L / min in a cylinder bore for a car engine, is deflected to the lid and flows back towards the sealing surface for the cylinder head.
• the electrode is poled cathodically, the workpiece anodic. Between the electrode and the cathode is a pulsed direct current with a voltage of 400-500 full.
• the electrolysis can also be done with unpulsed DC with or without superimposed AC component.
• the coating time is about 2 -10 minutes;
• the coating can be carried out simultaneously on all cylinders of a block by means of several electrodes.
• the layer thickness, the resulting layer roughness and the pore size are dependent on the applied electrical current, the voltage, the pulse program used as well as the coating time.
• the coating usually has a roughness of 2-3 ⁇ Rz and an Rpk value of z. B. 1, 0 - 2.0 ⁇ at a pore size of 2 -3 ⁇ . Regardless of the total layer thickness, it can be said in general that the depth of the edge zone change in the material of the workpiece is about 1/3 of the outwardly growing layer. At a total layer thickness of 20 ⁇ the Randzonenver selectedung is inwards z. B. about 5 ⁇ and about 15 ⁇ layer structure out into the hole.
• the specified roughness of the layer consists of a waviness, which is due to the pores and the structure of the layer.
• the coating is therefore finished, if necessary, by a smoothing operation, in order to level the undulations which have arisen during the coating. If the ripple is small, the smoothing process can be omitted.
• the smoothing can be done by honing or brushing. To level the waviness of the layer, you can work with conventional honing tools. However, it is recommended to minimize the removal and to change the (free) form of the surface only minimally to work with special Glätthhontechnikmaschinemaschineen. Their pendulum-suspended (hon) strip segments are relatively short, based on the length of the cylinder bore, but longer than the short-wave portions of the coating profile and thereby produce the desired smoothing, without significantly changing the geometry of the cylinder bore with minimal material removal.
• honing brushes which also adapt to the waviness due to the flexibility.
• These are brushes whose individual bristles consist, for example, of polyamide, in which abrasive hard materials, such as silicon carbide, corundum or diamond grain, are incorporated.
• so-called flex-honing brushes can be used, which are equipped at the bristle end, for example, with ceramic-bound cutting tubers.
• the finished smoothed layer topography is superimposed on the roughness before coating and on the layer-characteristic pores.
• the roughness profile changes, starting from the above values after coating to Rz values of 2.0-2.5 ⁇ m after smoothing.
• a suitable Rpk value is 0.13 pm.
• metal-bound diamond grains and ceramic-bound corundum or SiC grains have proven themselves.
• a layer can be produced with the method according to the invention in a manner which is easy to control in terms of manufacturing technology and which is particularly suitable for tribology because of its pore structure and high material hardness.
• the heat removal from the combustion chamber via the layer is particularly effective because the layer has been applied quasi-galvanically and thus the best possible substrate connection is made.
• the layer according to the invention does not influence the geometry of the cylinder bore, or does so only insignificantly, so that the desired shape can be completed even before coating.
• the order resulting from the coating and the material removal resulting from the optional smoothing must be taken into account.
• Figure 1 shows the Bohrmantelline after pretreatment by fine boring or honing
• Figure 2 shows the Bohrmantelline with applied layer, Figure 2.1 the waviness of the layer
• FIG. 2.2 shows a greatly enlarged representation of the surface of the layer before smoothing
• FIG. 3 shows the coated surface after-smoothing line
• Figure 3.1 shows the waviness of the layer after smoothing
• Figure 3.2 shows a greatly enlarged representation of the surface of the layer after smoothing
• Figure 4 is a schematic representation of a honing tool for smoothing.
• FIG 1 the surface line 2 of a pre-processed by honing (cylinder) bore is shown.
• the substrate is activated for the subsequent coating and has the desired nominal shape.
• Figure 2 the surface after treatment by PED is shown.
• a thickness of the coating 9 to about a third represents a change in the edge zone of the substrate and about two-thirds (reference numeral 3) causes a layer structure to the outside.
• Vorbearbeitungsw the bore (see the surface line 2) is designed so that the surface line 5 of the coating 9 is within the tolerance band of the finished bore.
• FIG. 2.1 the waviness of the surface line 5 according to FIG. 2 is shown.
• the ripple is too large, so that a smoothing process must be followed to reduce the ripple.
• FIG. 2.2 a SEM image of the surface after coating is shown. The pores 8 of the coating fall on.
• FIG. 3 shows the smoothed generatrix 6, which was achieved, for example, by honing with the tool shown in FIG. In this case, the surface line was smoothed so that a straight generatrix 6 is formed while maintaining the pores 8. After smoothing, the smoothed surface line 6 is also in the tolerance band of the finished bore.
• the surface of the smoothed generatrix is also shown in FIG. 3.1 in the profile section and in the SEM image FIG. 3.2.
• Figure 4 shows the principle of Glätthonens with a spring-mounted honing stone 7 at the beginning of Glätthonens.
• About the radial force FR is the radial loading of the coating. Due to the springs of the honing stone 7 has the ability to reduce the short ripples of the coating without changing the desired shape of the cylinder bore. When smoothing, the pore structures are largely retained.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Electrochemistry (AREA)
• Inorganic Chemistry (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Cylinder Crankcases Of Internal Combustion Engines (AREA)
• Combustion & Propulsion (AREA)
• General Engineering & Computer Science (AREA)
• Electroplating Methods And Accessories (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Cited By (1)

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Citations (7)

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• 2013
  • 2013-11-12 DE DE201310223011 patent/DE102013223011A1/de not_active Ceased
• 2014
  • 2014-11-11 EP EP14821488.5A patent/EP3068928B1/de not_active Not-in-force
  • 2014-11-11 US US15/036,111 patent/US9994966B2/en not_active Expired - Fee Related
  • 2014-11-11 JP JP2016529957A patent/JP2016540119A/ja active Pending
  • 2014-11-11 KR KR1020167012222A patent/KR20160085261A/ko not_active Withdrawn
  • 2014-11-11 WO PCT/DE2014/000574 patent/WO2015070833A1/de not_active Ceased

Patent Citations (7)

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