WO2024120826A1 - Procédé de dépôt électrolytique d'une couche de phosphate sur des surfaces de zinc - Google Patents

Procédé de dépôt électrolytique d'une couche de phosphate sur des surfaces de zinc Download PDF

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Publication number
WO2024120826A1
WO2024120826A1 PCT/EP2023/082652 EP2023082652W WO2024120826A1 WO 2024120826 A1 WO2024120826 A1 WO 2024120826A1 EP 2023082652 W EP2023082652 W EP 2023082652W WO 2024120826 A1 WO2024120826 A1 WO 2024120826A1
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WO
WIPO (PCT)
Prior art keywords
range
phosphating
solutions
process according
anions
Prior art date
Application number
PCT/EP2023/082652
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German (de)
English (en)
Inventor
Michael Wolpers
Ralf POSNER
Andreas Arnold
Original Assignee
Henkel Ag & Co. Kgaa
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Henkel Ag & Co. Kgaa filed Critical Henkel Ag & Co. Kgaa
Publication of WO2024120826A1 publication Critical patent/WO2024120826A1/fr

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Classifications

    • 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
    • C25D11/36—Phosphatising
    • 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
    • C25D9/00—Electrolytic coating other than with metals
    • C25D9/04—Electrolytic coating other than with metals with inorganic materials
    • C25D9/08—Electrolytic coating other than with metals with inorganic materials by cathodic processes

Definitions

  • the present invention relates to a method for phosphating metal surfaces, preferably alloy-galvanized steel strip surfaces, by treating them by immersion or spray dipping with acidic, aqueous solutions which may contain magnesium, phosphate and nitrate ions and, to further improve the layer formation, other ions selected from ammonium ions, alkali metal ions and/or fluoride ions, while simultaneously treating the workpieces cathodically with a direct current.
  • acidic, aqueous solutions which may contain magnesium, phosphate and nitrate ions and, to further improve the layer formation, other ions selected from ammonium ions, alkali metal ions and/or fluoride ions, while simultaneously treating the workpieces cathodically with a direct current.
  • This produces phosphate layers which have better corrosion properties than the well-known trication phosphating.
  • the phosphate layers formed also exhibit high abrasion resistance.
  • phosphate coatings with high abrasion resistance can be produced on metal surfaces using acidic phosphating baths containing phosphoric acid, manganese and copper ions and the simultaneous application of cathodic currents (JP-A-87/260 073).
  • JP-A-85/211 080 relates to a process for producing anti-corrosive layers on metal surfaces using zinc phosphating solutions, with the occasional application of a cathodic current.
  • a corrosion-resistant protective layer is produced, in particular, on the edges of the metal surfaces to be treated.
  • EP-A-0 171 790 is described in EP-A-0 171 790. In this process, the metal surfaces are treated with an acidic, aqueous solution containing zinc, phosphate and chlorine ions following a conventional zinc phosphating process, and a direct current is simultaneously applied to the anodically connected metal surfaces.
  • part of the nickel can in principle be replaced by a series of monovalent or divalent cations. These are selected, for example, from cobalt, manganese and magnesium. It is further stated that the nickel content of the Solution must be at least 1.0 g/l. The ratio to be used between low zinc and high nickel content is an essential part of technical teaching.
  • the present invention relates to a process for phosphating metal surfaces, preferably electrolytically or hot-dip galvanized steel strip surfaces, by treating them by immersion or spray dipping with acidic, aqueous solutions containing magnesium, phosphate and nitrate ions, which is characterized in that a) one works with phosphating solutions containing the following components:
  • NG 3 anions in the range of 0.1 to 60 g/l
  • Treatment duration in the range of 1 to 300 seconds, c) and wherein during phosphating the workpieces are further treated cathodically with a direct current of a density in the range of 1 to 150 mA/cm 2 .
  • the present invention relates to a workpiece comprising at least one metal surface phosphated by a method as disclosed and described herein.
  • At least two includes, but is not limited to, 2, 3, 4, 5, 6, and more.
  • At least one includes, but is not limited to, 1, 2, 3, 4, 5, 6, and more.
  • metal surfaces are mentioned in connection with the present invention, this means material surfaces made of iron, steel, zinc, aluminum and alloys of zinc or aluminum.
  • Examples of aluminum surfaces and their alloys include pure aluminum, AIMg and AIMgSi materials.
  • Examples of alloy components of zinc include iron, nickel or cobalt.
  • steel refers to unalloyed to low-alloyed steel, such as is used in the form of sheet metal for car body construction. Alloy-coated steels, which are surface-treated with zinc/nickel alloys, for example, are also included.
  • the method according to the invention is particularly suitable for phosphating electrolytically or hot-dip galvanized steel strip surfaces.
  • the use of galvanized steel, especially electrolytically galvanized steel in strip form, has become increasingly important in recent years.
  • galvanized steel includes both galvanization by electrolytic deposition and by hot-dip application and generally refers to so-called "pure zinc layers" as well as to known zinc alloys, in particular zinc/nickel alloys.
  • the process according to the invention is preferably carried out using the so-called dipping process; however, it is generally also possible to apply the phosphating solutions according to the invention to the substrate surfaces by spray dipping.
  • the workpieces to be treated are connected cathodically for the phosphating treatment, with a stainless steel electrode preferably being used as the counter electrode.
  • a metal container of the phosphating bath can also serve as the counter electrode; graphite electrodes or, in principle, all electrode materials known from the relevant state of the art can also be used as the counter electrode.
  • direct current does not only refer to “pure” direct currents, but also to practically similar currents, for example those that can be generated by full-wave rectification of a single-phase alternating current or by rectification of a three-phase alternating current. So-called pulsating direct currents and chopped direct currents can also be used for the purposes of the invention. The only thing that is important for the purposes of the invention is the current density of the direct current, which should lie in the range defined above.
  • suitable voltage values for the direct current that is to be used for the purposes of the present invention is deliberately omitted, since, taking into account the different conductivities of the phosphating baths on the one hand and the geometric arrangement of the electrodes on the other, a different relationship between current and voltage can exist.
  • concentration gradients are crucial for the formation mechanism of the phosphating layers, which are determined by the current density and not by the Bath voltage can be determined.
  • suitable voltage values for carrying out the process according to the invention in each individual case based on the values given for the current density.
  • phosphating solutions containing the following components are used:
  • Mg 2+ cations in the range of 1 to 10 g/l.
  • the following conditions are maintained during the phosphating treatment of the workpieces: pH value of the phosphating solutions in the range of 2.0 to 3.0,
  • Treatment duration in the range of 2 to 90 seconds, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 or 90 seconds.
  • the workpieces are cathodically treated with a direct current with a density of at least 5 mA/cm 2 , particularly preferably at least 10 mA/cm 2 , very particularly at least 20 mA/cm 2 , but preferably below 100 mA/cm 2 , very particularly preferably below 70 mA/cm 2 , for example with a density of 5 to 100 mA/cm 2 , for example from 10 to 70 mA/cm 2 , for example 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 or 69 mA/cm 2 .
  • the phosphating baths can also additionally contain alkali metal ions and/or ammonium ions.
  • phosphating baths according to the invention contain NH4 + , Li + , Na + and/or K + cations, preferably NH4 + , Li + , Na + and/or K + cations, particularly preferably NH4 + and/or K + cations.
  • phosphating solutions which additionally contain ammonium and/or alkali metal ions in the range from 0.1 to 10 g/l, preferably from 0.5 to 5 g/l, particularly preferably at least 1 g/l.
  • ammonium ions and/or alkali metal ions in the phosphating baths according to the invention results in an improvement in layer formation.
  • the phosphating baths contain NH4 + cations, preferably in the range of 0.1 to 10 g/l, particularly preferably in Range from 1 to 7 g/l. It turns out that in the presence of ammonium ions, particularly fine-crystalline phosphate layers are obtained.
  • phosphating aluminum-alloyed hot-dip galvanized steel surfaces for example hot-dip galvanized steel strip of types (Z), (ZM), (ZA), (AZ), (AS) or (ZF)
  • fluoride ions in the process according to the invention leads to a more uniform degree of coverage of the phosphating layers.
  • the fluoride anions can also be used in the form of complex fluorine compounds, for example tetrafluoroborate or hexafluorosilicate.
  • the use of phosphating baths is therefore preferred in which the amount of complex fluoride anions, preferably SiFe 2 anions, is in the range from 0.1 to 2 g/l, preferably in the range from 0.5 to 1.5 g/l.
  • the use of phosphating baths is preferred in which the amount of F anions is in the range from 0.01 to 2 g/l, preferably in the range from 0.1 to 1.5 g/l.
  • NQ 3 anions in the range of 0.1 to 60 g/l, particularly preferably 10 to 50 g/l, most preferably 20 to 40 g/l,
  • Mg 2+ cations in the range of 0.1 to 20 g/l, particularly preferably 1.0 to 15 g/l, most preferably 2.0 to 10 g/l, and
  • Alkali metal ions preferably selected from Li + , Na + and/or K + cations, particularly preferably K + cations, in the range from 0.1 to 10 g/l, preferably from 0.5 to 5 g/l, very particularly preferably from 0.5 to 3.5 g/l, or NH4 + cations in the range from 0.1 to 10 g/l, preferably from 1 to 7 g/l.
  • Mg 2+ cations in the range of 0.1 to 20 g/l, particularly preferably 1.0 to 15 g/l, most preferably 2.0 to 10 g/l, simple or complex fluoride anions in the range of 0.01 to 2 g/l, preferably 0.1 to 1.5 g/l and
  • Alkali metal ions preferably selected from Li + , Na + and/or K + cations, particularly preferably K + cations, in the range from 0.1 to 10 g/l, preferably from 0.5 to 5 g/l, very particularly preferably from 0.5 to 3.5 g/l, or
  • NH4 + cations in the range of 0.1 to 10 g/l, preferably 1 to 7 g/l.
  • SiFe 2 anions in the range of 0.1 to 2 g/l, preferably in the range of 0.5 to 1.5 g/l, and/or F anions, in the range of 0.01 to 2 g/l, preferably in the range of 0.1 to 1.5 g/l, and
  • Alkali metal ions preferably selected from Li + , Na + and/or K + cations, particularly preferably K + cations, in the range from 0.1 to 10 g/l, preferably from 0.5 to 5.0 g/l, very particularly preferably from 0.5 to 3.5 g/l, or
  • NH4 + cations in the range of 0.1 to 10 g/l, preferably 1 to 7 g/l.
  • the specified range of the pH value to be maintained includes, among other things, the specified range of the pH value to be maintained. If the pH value of the phosphating bath is not in the specified range, it is necessary to adjust the pH value of the phosphating bath to the specified range by adding acid, for example phosphoric acid, or by adding a base, for example sodium hydroxide solution. If values for the free acid or total acid content of the phosphating solutions are given in the examples below, these were determined in the manner described in the literature.
  • the so-called free acid point value is accordingly defined as the number of ml of 0.1 N NaOH required to titrate 10 ml of bath solution against dimethyl yellow, methyl orange or bromophenol blue.
  • the total acid score is then the number of ml of 0.1 N NaOH required to titrate 10 ml of bath solution using phenolphthalein as an indicator until the first pink color appears.
  • the phosphating solutions according to the invention generally have Free acid scores range from 0.5 to 4 and total acid scores range from 10 to 40.
  • the phosphating baths for carrying out the process according to the invention are generally prepared in the usual way, which is known per se to the person skilled in the art.
  • the following compounds, for example, can be used as starting materials for preparing the phosphating bath: Magnesium: in the form of magnesium nitrate, magnesium oxide, magnesium hydroxide or magnesium hydroxycarbonate; Phosphate: preferably in the form of phosphoric acid; Nitrate: in the form of the above-mentioned salts, optionally also in the form of the sodium salt; Alkali metal ions: e.g. NaH2PC, KH2PO4; Ammonium: e.g. NH4H2PC.
  • the fluoride ions which may be used in the bath are preferably used in the form of sodium fluoride or in the form of the above-mentioned complex compounds (e.g. MgSiFe, H2SiFe, NaF, NH4HF2.
  • the above-mentioned compounds are dissolved in water in the concentration ranges that are important for the invention; then, as also already mentioned above, the pH value of the phosphating solutions is adjusted to the desired value.
  • the metal surface to be treated must be completely wettable with water. For this purpose, it is generally necessary to clean and degrease the metal surfaces to be treated using methods that are known per se and are adequately described in the prior art.
  • it is also preferred that the workpieces to be phosphated are first subjected to a known activation pretreatment, in particular with titanium-containing activation solutions.
  • the workpieces to be phosphated it is also preferred to subject the workpieces to be phosphated to a known activation pretreatment after rinsing the cleaned and degreased workpieces with water, preferably with demineralized water.
  • titanium-containing activation solutions are used in this context, as described, for example, in DE-A-20 38 105 or DE-A-20 43 085.
  • the metal surfaces to be subsequently phosphated are treated with solutions which essentially contain titanium salts and sodium phosphate as activating agents, optionally together with organic components, for example alkyl phosphonates or polycarboxylic acids.
  • Soluble titanium compounds such as potassium titanium fluoride and in particular titanyl sulfate are preferably used as the titanium component.
  • Disodium orthophosphate is generally used as the sodium phosphate. Titanium-containing compounds and sodium phosphate are used in such proportions that the titanium content is at least 0.005% by weight, based on the weight of the titanium-containing compound and the sodium phosphate
  • the actual phosphating process takes place; the phosphated metal surfaces are then rinsed again with water, preferably with demineralized water.
  • Such a Passivation is always useful and advantageous when the metal surfaces phosphated using the process according to the invention are subsequently painted or otherwise coated with organic materials.
  • Typical suitable passivations are chromium-free acidic aqueous compositions based on water-soluble complex fluorides of the elements Zr, Ti, Hf and/or Si.
  • the phosphating layers produced using the method according to the invention can be used in all areas in which phosphate coatings are used.
  • a particularly advantageous application is in the preparation of metal surfaces for painting, for example by spray painting or electrocoating, or for coating with organic films.
  • a workpiece comprising at least one metal surface phosphated by a method as disclosed and described herein represents a further aspect of the present invention.
  • Substrate hot-dip galvanized (Z) sheet (specification: DX56+Z140MC)
  • Cathodic dip coating 20 pm (Cathoguard® 800 from BASF Coatings GmbH)
  • the values given are averages obtained from three parallel samples.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Treatment Of Metals (AREA)

Abstract

La présente invention concerne un procédé de phosphatation de surfaces métalliques, de préférence de surfaces de bandes d'acier galvanisées en alliage, par traitement de celles-ci par immersion ou immersion par pulvérisation avec des solutions aqueuses acides qui peuvent contenir des ions magnésium, des ions phosphate et des ions nitrate et, pour une amélioration supplémentaire de la formation de couche, éventuellement d'autres ions choisis parmi des ions ammonium, des ions de métal alcalin et/ou des ions fluorure, les pièces étant simultanément traitées cathodiquement avec un courant continu.
PCT/EP2023/082652 2022-12-07 2023-11-22 Procédé de dépôt électrolytique d'une couche de phosphate sur des surfaces de zinc WO2024120826A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP22211916.6 2022-12-07
EP22211916.6A EP4382641A1 (fr) 2022-12-07 2022-12-07 Procédé de dépôt électrolytique d'une couche de phosphate sur des surfaces de zinc

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WO2024120826A1 true WO2024120826A1 (fr) 2024-06-13

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Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2038105A1 (de) 1970-07-31 1972-02-10 Collardin Gmbh Gerhard Verfahren zum Aufbringen von Zinkphosphatschichten auf Oberflaechen aus Eisen,Stahl und feuerverzinktem Material
DE2043085A1 (en) 1970-08-31 1972-03-09 Collardin Gmbh Gerhard Zinc phosphate coating - of zinc electroplated material pre-activated with solns contg titanium salts, gelatine or alginates
JPS4928539A (fr) * 1972-07-12 1974-03-14
WO1985003089A1 (fr) 1984-01-06 1985-07-18 Ford Motor Company Revetement de conversion de phosphate a resistance alcaline
EP0171790A1 (fr) 1984-08-14 1986-02-19 Nippon Paint Co., Ltd. Phosphatation au zinc
EP0459541A1 (fr) * 1990-04-27 1991-12-04 METALLGESELLSCHAFT Aktiengesellschaft Procédé de phosphatation de surfaces métalliques
JP2000161429A (ja) 1998-11-26 2000-06-16 Bando Chem Ind Ltd 免震装置
JP2002047537A (ja) 2000-07-28 2002-02-15 Sumitomo Metals (Kokura) Ltd 丸棒材料
JP2010211080A (ja) 2009-03-12 2010-09-24 Ricoh Co Ltd 定着装置、及び、画像形成装置
JP2010260073A (ja) 2009-04-30 2010-11-18 Jfe Steel Corp 熱間仕上圧延機用ワークロール、熱間仕上圧延機列と圧延方法
EP2343399A1 (fr) * 2008-10-31 2011-07-13 Henkel AG & Co. KGaA Solution de traitement par conversion chimique d un matériau métallique et procédé de traitement
JP2014219193A (ja) 2013-05-10 2014-11-20 アイ２エム カンパニー，リミテッド 不織布の表面積の変化により加湿量が調節される自然加湿器（ａｈｕｍｉｄｉｆｉｅｒ）
EP3284850A1 (fr) * 2015-04-16 2018-02-21 Nippon Steel & Sumitomo Metal Corporation Tôle d'acier pour conteneur et procédé de fabrication de tôle d'acier pour conteneur

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2038105A1 (de) 1970-07-31 1972-02-10 Collardin Gmbh Gerhard Verfahren zum Aufbringen von Zinkphosphatschichten auf Oberflaechen aus Eisen,Stahl und feuerverzinktem Material
DE2043085A1 (en) 1970-08-31 1972-03-09 Collardin Gmbh Gerhard Zinc phosphate coating - of zinc electroplated material pre-activated with solns contg titanium salts, gelatine or alginates
JPS4928539A (fr) * 1972-07-12 1974-03-14
WO1985003089A1 (fr) 1984-01-06 1985-07-18 Ford Motor Company Revetement de conversion de phosphate a resistance alcaline
EP0171790A1 (fr) 1984-08-14 1986-02-19 Nippon Paint Co., Ltd. Phosphatation au zinc
EP0459541A1 (fr) * 1990-04-27 1991-12-04 METALLGESELLSCHAFT Aktiengesellschaft Procédé de phosphatation de surfaces métalliques
JP2000161429A (ja) 1998-11-26 2000-06-16 Bando Chem Ind Ltd 免震装置
JP2002047537A (ja) 2000-07-28 2002-02-15 Sumitomo Metals (Kokura) Ltd 丸棒材料
EP2343399A1 (fr) * 2008-10-31 2011-07-13 Henkel AG & Co. KGaA Solution de traitement par conversion chimique d un matériau métallique et procédé de traitement
JP2010211080A (ja) 2009-03-12 2010-09-24 Ricoh Co Ltd 定着装置、及び、画像形成装置
JP2010260073A (ja) 2009-04-30 2010-11-18 Jfe Steel Corp 熱間仕上圧延機用ワークロール、熱間仕上圧延機列と圧延方法
JP2014219193A (ja) 2013-05-10 2014-11-20 アイ２エム カンパニー，リミテッド 不織布の表面積の変化により加湿量が調節される自然加湿器（ａｈｕｍｉｄｉｆｉｅｒ）
EP3284850A1 (fr) * 2015-04-16 2018-02-21 Nippon Steel & Sumitomo Metal Corporation Tôle d'acier pour conteneur et procédé de fabrication de tôle d'acier pour conteneur

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
M. H. ABBAS: "Finishing", October 1984, pages: 30 - 31

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