US20060201815A1 - Method for production of oxide and silicon layers on a metal surface - Google Patents

Method for production of oxide and silicon layers on a metal surface Download PDF

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US20060201815A1
US20060201815A1 US11/372,372 US37237206A US2006201815A1 US 20060201815 A1 US20060201815 A1 US 20060201815A1 US 37237206 A US37237206 A US 37237206A US 2006201815 A1 US2006201815 A1 US 2006201815A1
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metal surface
electrolyte
power
oxide
polarity
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US11/372,372
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Reinhold Separautzki
Andreas Mucha
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Dr Ing HCF Porsche AG
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Dr Ing HCF Porsche AG
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Assigned to DR. ING. H.C.F. PORSCHE AKTIENGESELLSCHAFT reassignment DR. ING. H.C.F. PORSCHE AKTIENGESELLSCHAFT ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SEPARAUTZKI, REINHOLD, MUCHA, ANDREAS
Publication of US20060201815A1 publication Critical patent/US20060201815A1/en
Assigned to DR. ING. H.C.F. PORSCHE AKTIENGESELLSCHAFT reassignment DR. ING. H.C.F. PORSCHE AKTIENGESELLSCHAFT ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SEPARAUTZKI, REINHOLD, MUCHA, ANDREAS
Assigned to DR. ING. H.C.F. PORSCHE AKTIENGESELLSCHAFT (COMPANY NUMBER 722287) reassignment DR. ING. H.C.F. PORSCHE AKTIENGESELLSCHAFT (COMPANY NUMBER 722287) MERGER (SEE DOCUMENT FOR DETAILS). Assignors: DR. ING. H.C.F. PORSCHE AKTIENGESELLSCHAFT
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    • 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
    • C25D11/12—Anodising more than once, e.g. in different baths
    • 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
    • C25D11/024—Anodisation under pulsed or modulated current or potential
    • 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
    • C25D11/20—Electrolytic after-treatment
    • 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

Definitions

  • the invention relates to a method of producing oxide and silicate layers on metal surfaces in a liquid electrolyte, particularly for aluminum metals, magnesium metals and their alloys, as well as for tantalum, titanium, niobium and zirconium.
  • German Patent Document DE 41 04 847 C2 shows a method of ceramizing metal surfaces, by which metal parts are ceramized in a liquid electrolyte by spark discharge.
  • the parts are connected to the multiphase periodic power source such that the parts alternately take over the function of the anode and cathode.
  • a counterelectrode, which is not to be ceramized, is therefore not required.
  • German Patent DD 299 074 A5 a lubricant on an inorganic base for pressing and drawing is disclosed which consists of a multilayer construction of characteristic oxides.
  • the metal parts in a liquid electrolyte are subjected to a pulse voltage which is always rectified.
  • the FIGURE shows a cross section showing layers on a metal.
  • An object of certain embodiments the present invention is to provide a method of producing oxide and silicate layers on metal surfaces, particularly for magnesium, aluminum and their alloys as well as for tantalum, titanium, niobium and zirconium, by means of which a protective layer against corrosion and wear can be produced economically.
  • This object is achieved in certain embodiments in that, during the production of the oxide and silicate layers in the liquid electrolyte, a bipolar power source is used whose polarity can be changed.
  • the effect of the current takes place in the second or millisecond range.
  • the pole reversal takes place in the millisecond range.
  • the density of the oxide and silicate layers can be noticeably increased.
  • the pulse ratio be selected to be greater than 1:1; that is, the time period during which the part to be coated- is connected as a cathode is to be selected longer than the time period during which the part to be coated is connected as an anode.
  • a forged motor vehicle wheel consisting of the magnesium alloy AZ80 is first cleaned in a bath of 10% ethanoic acid.
  • the motor vehicle wheel is immersed in an electrolyte I consisting of an aqueous solution of potassium hydroxide (KOH) and sodium fluoride (NaF) and is connected with a power source.
  • the power source supplies a current of between 30 and 100 A.
  • the motor vehicle wheel is connected as a cathode and is activated for approximately 40 seconds. Subsequently, the current is pulsed for 30 minutes such that, for a period of 30 ms, the motor vehicle wheel is connected as an anode and, for a period of 130 ms, is connected as a cathode.
  • a layer of magnesium oxides and aluminum oxides is created which has a thickness of from 3 to 10 ⁇ m.
  • the further unipolar coating takes place in the electrolyte II consisting of an aqueous solution of KOH, NaF and sodium metasilicate (Na 2 O 3 Si).
  • the wheel, immersed in the electrolyte II is in each case connected for 55 ms with +250 V as an anode and for 500 ms at ⁇ 250 V as a cathode.
  • the entire treatment takes 20 minutes.
  • a layer of magnesium silicate is created which has a thickness of 10 to 20 ⁇ m.
  • Both electrolytes are tempered or cooled to 30 to 40° C.
  • the total layer of magnesium oxides and aluminum oxides and subsequently magnesium silicate produced in this manner and having a thickness of approximately 25 ⁇ m is tight with respect to corrosive media.
  • the single figure is a micrograph of the total layer. According to the above-described method, an oxide layer 2 of a thickness of 3.25 ⁇ m consisting of magnesium oxides and a silicate layer 3 of a thickness of 11.61 ⁇ m consisting of magnesium silicate are applied to a wheel 1 consisting of magnesium.

Abstract

The invention relates to a method of producing oxide and silicate layers on metal surfaces in a liquid electrolyte, particularly for aluminum metals, magnesium metals and their alloys, as well as for tantalum, titanium, niobium and zirconium. During the production of the oxide and silicate layers in the liquid electrolyte, a bipolar power source is used whose polarity can be changed.

Description

    FIELD OF THE INVENTION
  • The invention relates to a method of producing oxide and silicate layers on metal surfaces in a liquid electrolyte, particularly for aluminum metals, magnesium metals and their alloys, as well as for tantalum, titanium, niobium and zirconium.
    • BACKGROUND OF THE INVENTION
  • German Patent Document DE 41 04 847 C2 shows a method of ceramizing metal surfaces, by which metal parts are ceramized in a liquid electrolyte by spark discharge. In this case, the parts are connected to the multiphase periodic power source such that the parts alternately take over the function of the anode and cathode. A counterelectrode, which is not to be ceramized, is therefore not required.
  • In German Patent DD 299 074 A5, a lubricant on an inorganic base for pressing and drawing is disclosed which consists of a multilayer construction of characteristic oxides. For producing these oxide layers, the metal parts in a liquid electrolyte are subjected to a pulse voltage which is always rectified.
  • Furthermore, a surface protection for magnesium materials is known from the brochure “AHC Oberflächentechnik: Magoxyd-Coat” (“AHC Surface Engineering: Magoxide Coat”), in which a protective ceramic layer of magnesium oxide is applied to the surface of a magnesium part to be protected. The production of this layer takes place by anodic oxidation in a cooled, slightly alkaline electrolyte.
    • BRIEF DESCRIPTION OF THE DRAWING
  • The FIGURE shows a cross section showing layers on a metal.
    • SUMMARY OF THE INVENTION
  • An object of certain embodiments the present invention is to provide a method of producing oxide and silicate layers on metal surfaces, particularly for magnesium, aluminum and their alloys as well as for tantalum, titanium, niobium and zirconium, by means of which a protective layer against corrosion and wear can be produced economically.
  • This object is achieved in certain embodiments in that, during the production of the oxide and silicate layers in the liquid electrolyte, a bipolar power source is used whose polarity can be changed.
  • It was found that the layer buildup rate in the case of this method is higher than in the case of the known methods using direct current or pulsed current. Oxide and silicate layers of a thickness of more than 20 μm can therefore be produced more rapidly and cost-effectively.
  • Thus, the effect of the current takes place in the second or millisecond range. In-between, the pole reversal takes place in the millisecond range. As a result the density of the oxide and silicate layers can be noticeably increased. In addition, it is suggested that the pulse ratio be selected to be greater than 1:1; that is, the time period during which the part to be coated- is connected as a cathode is to be selected longer than the time period during which the part to be coated is connected as an anode.
  • Different layer sequences are permitted by means of successive coatings in different electrolytes.
  • An exemplary embodiment of the invention is described in detail in the following.
  • A forged motor vehicle wheel consisting of the magnesium alloy AZ80 is first cleaned in a bath of 10% ethanoic acid.
  • In a second step, the motor vehicle wheel is immersed in an electrolyte I consisting of an aqueous solution of potassium hydroxide (KOH) and sodium fluoride (NaF) and is connected with a power source. The power source supplies a current of between 30 and 100 A.
  • First, the motor vehicle wheel is connected as a cathode and is activated for approximately 40 seconds. Subsequently, the current is pulsed for 30 minutes such that, for a period of 30 ms, the motor vehicle wheel is connected as an anode and, for a period of 130 ms, is connected as a cathode. A layer of magnesium oxides and aluminum oxides is created which has a thickness of from 3 to 10 μm.
  • Then the further unipolar coating takes place in the electrolyte II consisting of an aqueous solution of KOH, NaF and sodium metasilicate (Na2O3Si). The wheel, immersed in the electrolyte II, is in each case connected for 55 ms with +250 V as an anode and for 500 ms at −250 V as a cathode. The entire treatment takes 20 minutes. During the treatment time, a layer of magnesium silicate is created which has a thickness of 10 to 20 μm.
  • Both electrolytes are tempered or cooled to 30 to 40° C.
  • The total layer of magnesium oxides and aluminum oxides and subsequently magnesium silicate produced in this manner and having a thickness of approximately 25 μm is tight with respect to corrosive media. The single figure is a micrograph of the total layer. According to the above-described method, an oxide layer 2 of a thickness of 3.25 μm consisting of magnesium oxides and a silicate layer 3 of a thickness of 11.61 μm consisting of magnesium silicate are applied to a wheel 1 consisting of magnesium.
  • As other alternatives, the following layer sequences can be produced:
  • Alternative A: By the successive use of electrolyte I, then electrolyte II and then again electrolyte I, an oxide layer, silicate layer, oxide layer sequence.
  • Alternative B: By the successive use of electrolyte II, then electrolyte I and then again electrolyte II, a silicate layer, oxide layer, silicate layer sequence.
  • The foregoing description and examples have been set forth merely to illustrate the invention and are not intended to be limiting. Since modifications of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed broadly to include all variations within the scope of the appended claims and equivalents thereof.

Claims (13)

1. A method of producing oxide-silicate layers on a metal surface in a liquid electrolyte, said method comprising:
connecting a bipolar power source to the metal surface, applying power and
alternating the polarity of the power.
2. The method of claim 1, wherein said metal surface comprises at least one metal selected from the group consisting of aluminum, alloys of aluminum, magnesium, alloys of magnesium, tantalum, titanium, niobium and zirconium.
3. The method of claim 1, wherein the step of alternating the polarity of the power source takes place in the millisecond range.
4. The method of claim 3, wherein the time period during which the part to be coated is connected as an anode is shorter than the time period during which the part to be coated is connected as a cathode or is without current.
5. The method of claim 1, further comprising the step of controlling the layer sequences created.
6. The method of claim 5, wherein the layer sequences created are controlled by selecting an electrolyte.
7. The method of claim 1, wherein the metal surface is immersed in a first electrolyte during a time in which power is applied.
8. The method of claim 7, wherein the first electrolyte comprises an aqueous solution of potassium hydroxide and sodium fluoride.
9. The method of claim 7, further comprising the steps of immersing the metal surface in a second electrolyte during a time in which power is applied.
10. The method of claim 9, wherein the second electrolyte comprises an aqueous solution of potassium hydroxide, sodium fluoride and sodium metasilicate.
11. The method of claim 1, wherein power having one polarity is applied for a period of at least 30 milliseconds.
12. A metal surface having oxide-silicate layers thereon, wherein said metal surface is produced by the process of claim 1.
13. A method of producing oxide-silicate layers on a metal surface in a liquid electrolyte, said method comprising:
immersing the metal surface in a first electrolyte,
connecting a bipolar power source to the metal surface, applying power,
alternating the polarity of the power,
immersing the metal surface in a second electrolyte, then
repeating the steps of applying power and
alternating the polarity of the power.
US11/372,372 2005-03-11 2006-03-10 Method for production of oxide and silicon layers on a metal surface Abandoned US20060201815A1 (en)

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DE102005011322.2 2005-03-11
DE102005011322A DE102005011322A1 (en) 2005-03-11 2005-03-11 Process for the preparation of oxide and silicate layers on metal surfaces

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090278396A1 (en) * 2008-05-12 2009-11-12 Gm Global Technology Operations, Inc. Corrosion isolation of magnesium components
CN102367584A (en) * 2011-09-19 2012-03-07 北京科技大学 Metal microarc oxidation electrolyte and method for forming black ceramic coating on metal surface by microarc oxidation
US11118092B2 (en) 2018-09-04 2021-09-14 Saudi Arabian Oil Company Synthetic layered magnesium silicates and their derivatives for high performance oil-based drilling fluids
US11414584B2 (en) * 2018-09-04 2022-08-16 Saudi Arabian Oil Company Viscosity supporting additive for water-based drilling and completions fluids
US11898084B2 (en) 2018-09-04 2024-02-13 Saudi Arabian Oil Company Suspension supporting additive for water-based drilling and completions fluids

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102304739B (en) * 2011-09-19 2015-06-03 北京科技大学 Micro-arc oxidation preparation method of high wear resistant and corrosion resistant self-lubricating ceramic layer and electrolyte thereof
DE102017217227A1 (en) * 2017-09-27 2019-03-28 Bayerische Motoren Werke Aktiengesellschaft Wheel discs - Radanlagenverbindung for a vehicle wheel

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US3902976A (en) * 1974-10-01 1975-09-02 S O Litho Corp Corrosion and abrasion resistant aluminum and aluminum alloy plates particularly useful as support members for photolithographic plates and the like
US4517059A (en) * 1981-07-31 1985-05-14 The Boeing Company Automated alternating polarity direct current pulse electrolytic processing of metals
US5616229A (en) * 1994-06-01 1997-04-01 Almag Al Process for coating metals
US6365028B1 (en) * 1997-12-17 2002-04-02 Isle Coat Limited Method for producing hard protection coatings on articles made of aluminum alloys
US20020112962A1 (en) * 2000-04-26 2002-08-22 Jacques Beauvir Oxidising electrolytic method for obtaining a ceramic coating at the surface of a metal
US6495267B1 (en) * 2001-10-04 2002-12-17 Briggs & Stratton Corporation Anodized magnesium or magnesium alloy piston and method for manufacturing the same
US6916414B2 (en) * 2001-10-02 2005-07-12 Henkel Kommanditgesellschaft Auf Aktien Light metal anodization
US6919012B1 (en) * 2003-03-25 2005-07-19 Olimex Group, Inc. Method of making a composite article comprising a ceramic coating

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DE3808609A1 (en) * 1988-03-15 1989-09-28 Electro Chem Eng Gmbh METHOD OF GENERATING CORROSION AND WEAR RESISTANT PROTECTION LAYERS ON MAGNESIUM AND MAGNESIUM ALLOYS
DE4104847A1 (en) * 1991-02-16 1992-08-20 Friebe & Reininghaus Ahc Prodn. of uniform ceramic layers on metal surfaces by spark discharge - partic. used for metal parts of aluminium@, titanium@, tantalum, niobium, zirconium@, magnesium@ and their alloys with large surface areas
RU2023762C1 (en) * 1991-06-27 1994-11-30 Научно-техническое бюро "Энергия" Московского межотраслевого объединения "Ингеоком" Method for applying coatings to products made of aluminum alloys
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Patent Citations (8)

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Publication number Priority date Publication date Assignee Title
US3902976A (en) * 1974-10-01 1975-09-02 S O Litho Corp Corrosion and abrasion resistant aluminum and aluminum alloy plates particularly useful as support members for photolithographic plates and the like
US4517059A (en) * 1981-07-31 1985-05-14 The Boeing Company Automated alternating polarity direct current pulse electrolytic processing of metals
US5616229A (en) * 1994-06-01 1997-04-01 Almag Al Process for coating metals
US6365028B1 (en) * 1997-12-17 2002-04-02 Isle Coat Limited Method for producing hard protection coatings on articles made of aluminum alloys
US20020112962A1 (en) * 2000-04-26 2002-08-22 Jacques Beauvir Oxidising electrolytic method for obtaining a ceramic coating at the surface of a metal
US6916414B2 (en) * 2001-10-02 2005-07-12 Henkel Kommanditgesellschaft Auf Aktien Light metal anodization
US6495267B1 (en) * 2001-10-04 2002-12-17 Briggs & Stratton Corporation Anodized magnesium or magnesium alloy piston and method for manufacturing the same
US6919012B1 (en) * 2003-03-25 2005-07-19 Olimex Group, Inc. Method of making a composite article comprising a ceramic coating

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090278396A1 (en) * 2008-05-12 2009-11-12 Gm Global Technology Operations, Inc. Corrosion isolation of magnesium components
CN102367584A (en) * 2011-09-19 2012-03-07 北京科技大学 Metal microarc oxidation electrolyte and method for forming black ceramic coating on metal surface by microarc oxidation
US11118092B2 (en) 2018-09-04 2021-09-14 Saudi Arabian Oil Company Synthetic layered magnesium silicates and their derivatives for high performance oil-based drilling fluids
US11414584B2 (en) * 2018-09-04 2022-08-16 Saudi Arabian Oil Company Viscosity supporting additive for water-based drilling and completions fluids
US11674069B2 (en) 2018-09-04 2023-06-13 Saudi Arabian Oil Company Synthetic layered magnesium silicates and their derivatives for high performance oil-based drilling fluids
US11898084B2 (en) 2018-09-04 2024-02-13 Saudi Arabian Oil Company Suspension supporting additive for water-based drilling and completions fluids

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DE102005011322A1 (en) 2006-09-14
EP1700934A2 (en) 2006-09-13
EP1700934A3 (en) 2008-08-06

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