EP3559313A1 - Zusammensetzungen enthaltend diazonium-ionen zur korrosionsschützenden vorbehandlung metallischer bauteile - Google Patents
Zusammensetzungen enthaltend diazonium-ionen zur korrosionsschützenden vorbehandlung metallischer bauteileInfo
- Publication number
- EP3559313A1 EP3559313A1 EP17829612.5A EP17829612A EP3559313A1 EP 3559313 A1 EP3559313 A1 EP 3559313A1 EP 17829612 A EP17829612 A EP 17829612A EP 3559313 A1 EP3559313 A1 EP 3559313A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- aqueous composition
- composition
- composition according
- ions
- amount
- 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.)
- Withdrawn
Links
Classifications
-
- 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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/34—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides
Definitions
- compositions containing diazonium ions for corrosion-protective pretreatment of metallic components are provided.
- the present invention relates to a method for the corrosion-protective pretreatment of metallic components which are at least partially made of metallic materials of the elements iron, zinc and / or aluminum, using an acidic aqueous composition containing free fluoride and aromatic diazonium ions.
- the prior art discloses a multiplicity of pretreatment methods of components made of metals, in particular of aluminum, for imparting corrosion protection and as a paint primer based on acidic compositions.
- the aluminum surface is freed in a first step by the natural or caused by the manufacturing process oxide layer by pickling or pickling.
- the pickling not only involves the removal of the oxide layer, but typically includes pickling of the aluminum-made component itself to provide a homogeneous reproducible metallic surface for subsequent passivation.
- arylamines can be converted into diazonium ions in solution at low pH and in the presence of nitrite.
- these diazonium compounds can be attached to metallic surfaces in order to provide them with corrosion protection.
- diazotized arylamines can be deposited in the presence of free fluoride in a self-initiated process on metallic components without the removal of the oxide layer is necessary before and give them a comparable or even improved corrosion protection over known methods.
- the free fluoride etches through the oxide layer, forming the fluoride with the oxide soluble complexes, exposing the underlying metal.
- This solution dissolves at the acidic pH and forms metal cations and electrons, the electrons forming hydrogen gas with the protons or reacting with the diazonium group to form a radical and gaseous nitrogen.
- the generated radical is unstable and reacts with the metal surface to form a covalent bond, the so-called "grafting".
- the present invention therefore relates to a method for corrosion-protective pretreatment of a metallic component, which is at least partially composed of a material which consists predominantly of one or more of the metals aluminum, iron and zinc, by bringing the component into contact with an aqueous composition having a pH below 3 containing at least 0.0005 mol / kg of aromatic diazonium ions and at least 0.001 g / kg of free fluoride.
- the invention also relates to an aqueous chromium (VI) and phosphate-free composition having a pH below 3.0 and containing at least 0.04 g / kg of an aromatic diazonium ion and at least 0.001 g / kg, preferably at least 0.004 g / kg of free fluoride ions obtainable by adding 0.04 - 10 g / kg of an aromatic primary amine and at least one source of nitrite ions, the total amount of such sources being suitable for nitrite ions, 0.005 To release 5 g / kg of nitrite ions to an acidic aqueous phase having a pH which corresponds to a pH predetermined by the aqueous composition, containing an amount of free fluoride corresponding to an amount predetermined by the aqueous composition corresponds to free fluoride, and optionally subsequent addition of an acid to adjust the pH.
- VI aqueous chromium
- phosphate-free composition having a pH below 3.0 and
- a composition is "phosphate-free" if the proportion of phosphates dissolved in water is less than 100 mg / kg, preferably less than 20 mg / kg calculated as the amount of phosphorus.
- a composition is "chromium-free" if the proportion of compounds of the element chromium dissolved in water in the oxidation state + VI is less than 100 mg / kg, preferably less than 20 ppm.
- the components treated according to the present invention can be any arbitrarily shaped and configured spatial structures originating from a fabrication process, in particular also semi-finished products such as strips, sheets, rods, tubes, etc., and composite structures joined together from the aforementioned semifinished products, wherein the semifinished products preferably by gluing, welding and / or flanging to the composite structure are connected together.
- a metallic material consists predominantly of the elements iron, zinc and / or aluminum, if the atomic proportion of these elements in the material as a whole is greater than 50 at .-%.
- the metallic material can also be a metallically coated substrate, insofar as the metallic coating has a layer thickness of at least 1 ⁇ m and more than 50 at.% Consists of the constituent elements defined above.
- Such materials are all plated iron materials such as electrolytically or hot dip galvanized steel, preferably platings in the form of zinc (Z), aluminum-silicon (AS), zinc-magnesium (ZM), zinc-aluminum (ZA), aluminum-zinc (AZ). or zinc-iron (ZF).
- the metal surfaces are freed from the oxide layer due to the production process in one process step and provided with a corrosion-protecting organic layer.
- no previous step of removing the oxide layer for example by means of pickling, is provided.
- the aqueous composition used in the process according to the invention and also included as such contains diazonium ions which can be formed in situ.
- the aqueous composition is therefore obtainable, for example, by adding at least 0.0005 mol / kg of an aromatic primary amine and at least one source of nitrite ions, the total amount of all such sources being suitable for nitrite ions, at least 0.0005 mol / kg Nitrite, to an aqueous phase having a pH which corresponds to a predetermined by the aqueous composition pH, ie is below 3 or adjusted to an appropriate pH by addition of an acid.
- the aqueous composition further contains an amount of free fluoride corresponding to an amount of free fluoride predetermined by the aqueous composition, i. at least 0.001 g / kg of free fluoride.
- the aqueous composition has a pH below 2.5, more preferably below 2.0, but preferably above 1.0.
- the aqueous composition may be particularly sulfuric, i. Sulfuric acid but not more than 0.001 mol / L of another strong acid with pKsl value of less than 2 included.
- the aromatic amine is a compound of the formula (I)
- the radicals R are preferably bonded in the para position relative to the amino group.
- two or more R together with the carbon atoms to which they are attached may also form a 5-8 membered (hetero) alicyclic or (hetero) aromatic ring, which in turn may be substituted with one or more Rs, which may in turn be further Can combine wrestling.
- a core structure for example, naphthalene, anthracene and phenanthrene rings can result.
- 4-aminobenzoic acid is especially preferred as the aromatic amine in the context of the present invention.
- nitrite ions for example, nitrous acid (HNO2) and its water-soluble salts and alkyl nitrates can be used.
- the molar ratio of aromatic primary amine groups to nitrite ions is not greater than 5: 1, but is preferably greater than 1:10.
- the proportion by weight of the aromatic diazonium ions based on the total amount of all organic compounds contained in the aqueous composition which do not constitute a source of nitrite ions is preferably at least 50%, more preferably at least 80%, particularly preferably at least 90%.
- the aqueous composition additionally contains free fluoride.
- an acidic composition of the invention contains a source of fluoride ions.
- the source of fluoride ions is any inorganic compound capable of being dissolved or dispersed in water to liberate fluoride ions.
- a preferred source of fluoride ions are complex or simple fluorides.
- Simple fluorides are understood to mean hydrofluoric acid and its salts, such as alkali fluorides, ammonium fluoride or ammonium bifluoride, whereas complex fluorides are coordination compounds according to the invention in which fluorides are coordinated as ligands of one or more central atoms.
- Preferred representatives of the complex fluorides are fluorine-containing complex compounds of the elements Zr, Ti or Si.
- the proportion of free fluoride in the aqueous composition is preferably at least 0.004 g / kg, but more preferably not more than 0.1 g / kg.
- the free fluoride content can be determined by means of calibrated fluoride-sensitive electrode directly in the acidic aqueous composition at 20 ° C.
- the aqueous composition may in various embodiments contain water-soluble compounds of the elements Zr, Ti and / or Si. These can be used, for example, as described above, as complex fluorides. Accordingly, the aqueous composition preferably contains a total of at least 0.002% by weight (0.02 g / kg), preferably at least 0.005% by weight, of water-soluble compounds of the elements Zr, Ti and / or Si calculated as the amount of Zr in the aqueous composition contains, but preferably not more than 0.2 wt .-% total (2 g / kg) of water-soluble compounds of the elements Zr, Ti and / or Si calculated as the amount of Zr.
- the acidic aqueous phase can be added, for example, fluorometallates of the elements Zr, Ti and / or Si, preferably hexafluorozirconates, hexafluorotitanates and / or hexafluorosilicates, more preferably hexafluorozirconates and / or hexafluorotitanates, or their free acids.
- Suitable representatives of the water-soluble compounds of the elements Zr and / or Ti are, for example, compounds such as H2ZrF6, IZXFQ, Na2ZrF6 and (NH4) 2ZrF6 and the analogous titanium compounds.
- fluorine-free compounds of the elements Si, Zr or Ti, in particular of the element Zr can also be used as water-soluble compounds according to the invention, for example (NH 4) 2 Zr (OH) 2 (CO 3) 2 or TiO (SO 4).
- the molar ratio of total fluoride content to the total amount of the compounds of the elements Si, Zr or Ti is based on the elements Zr, Ti and Si is greater than 4.5, preferably greater than 5.0, more preferably greater than 5.5.
- the total fluoride content can be determined with a fluoride-sensitive electrode in a TISAB buffered aliquot of the acidic aqueous composition at 20 ° C (TISAB: "Total Lonic Strength Adjustment Buffer”), where the volume-related mixing ratio of buffer to the aliquot of the acidic
- TISAB buffer is prepared by dissolving 58 g of NaCl, 1 g of sodium citrate and 50 ml of glacial acetic acid in 500 ml of deionized water ( ⁇ ⁇ ⁇ 1 ) and setting a pH of 5.3 by means of 5 N NaOH and make up to a total volume of 1000 ml again with deionized water (K ⁇ Scnr 1 ).
- the treatment of such components has proved to be advantageous, which at least partially consist of metallic materials of the elements iron, zinc and / or aluminum, in particular aluminum. On the surfaces of this metallic materials of the elements iron, zinc and / or aluminum, in particular aluminum.
- a metallic material of the elements iron, zinc and / or aluminum is characterized in that its content of said metals is more than 50 at .-%.
- Preferred iron materials are steel, the steel being comprised of metallic materials whose mass fraction of iron is greater than that of any other element, and whose carbon content, excluding carbides, is less than 2.06% by weight.
- metallic components which are at least partially composed of a material which consists predominantly of aluminum.
- the inventive methods comprise one or more rinsing and / or drying steps after contacting the component with the acidic aqueous composition.
- a "rinsing step" in the sense of the present invention refers to a process which is intended solely for the purpose of using an immediately preceding wet-chemical treatment step, which is dissolved in a wet film adhering to the component To remove rinsing solution from the surface of the component as much as possible without the active components to be removed are replaced by others.
- Active components in this context are constituents contained in a liquid phase which cause an analytically detectable coating of the metal surfaces of the component with elemental constituents of the active components.
- a “drying step” in the context of the present invention refers to a process in which the surfaces of the metallic component having a wet film are to be dried with the aid of technical measures, for example supplying thermal energy or passing an air stream.
- the layers obtained by the described methods typically have thicknesses of 1-10, in particular 1-7, ⁇ .
- the total content of organic carbon on the surface is usually 10 to 5000 mg / m 2 , particularly preferably 50 to 3000 mg / m 2 , in particular 150 to 1500 mg / m 2 .
- the processes can be carried out at temperatures of 20 to 60, preferably 30 to 50 ° C.
- the methods of the present invention described herein have the advantage of preventing the grafting of diazonium molecules to oxidized metal surfaces without the need to remove the oxides in a previous step, i. in a single step, without the need for an external power source. Furthermore, such thick layers of organic molecules result even on complex structures that confer excellent corrosion resistance.
- Infrared reflection absorption spectroscopy was used to identify 4-aminobenzoic acid molecules on aluminum surfaces. Defatted and cleaned aluminum alloy AA6014 panels were treated as follows:
- Degreased and cleaned plates of aluminum alloy AA6014 were determined by immersion in a solution containing 8 g / L H2SO4, and 2.3 g / LH 2 TiF 6 (BONDERITE 2040®) (IV) and treated with AA6014 plates treated by immersion in a solution containing 8 g / L H2SO4, 2.3g / L H2T1F6 (BONDERITE 2040®), 5mM 4-aminobenzoic acid, and 5mM sodium nitrite (V).
- the plates were rinsed with DI water, coated with Automotive E-varnish and then subjected to Filiform corrosion tests for 1008 hours (DIN EN 3665).
- DI water coated with Automotive E-varnish and then subjected to Filiform corrosion tests for 1008 hours (DIN EN 3665).
- a degreased and cleaned plate of aluminum alloy AA6014 with E-coat coating but without further treatment was used. The results are shown in Table 2.
- the plate (V) treated according to the invention shows better corrosion resistance despite shorter treatment.
- Degreased and cleaned plates of aluminum alloy AA6014 were treated by immersion in a solution containing 8 g / L H2SO4, 2.3 g / LH 2 TiF 6 (BONDERITE 2040®), 5 mM 4-aminobenzoic acid and 5 mM of sodium nitrite (V). Additional treatments were performed for 90 seconds (VI) and 180 seconds (VII). The panels were rinsed with DI water and coated with Automotive E varnish and subjected to filiform corrosion tests for 1008 hours (DIN EN 3665). The results are shown in Table 3.
- the layer thickness which can be controlled over the immersion time, has a positive effect on the corrosion resistance.
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- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Treatment Of Metals (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP16206537 | 2016-12-23 | ||
PCT/EP2017/081903 WO2018114371A1 (de) | 2016-12-23 | 2017-12-07 | Zusammensetzungen enthaltend diazonium-ionen zur korrosionsschützenden vorbehandlung metallischer bauteile |
Publications (1)
Publication Number | Publication Date |
---|---|
EP3559313A1 true EP3559313A1 (de) | 2019-10-30 |
Family
ID=57609737
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP17829612.5A Withdrawn EP3559313A1 (de) | 2016-12-23 | 2017-12-07 | Zusammensetzungen enthaltend diazonium-ionen zur korrosionsschützenden vorbehandlung metallischer bauteile |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP3559313A1 (de) |
WO (1) | WO2018114371A1 (de) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR3088936B1 (fr) * | 2018-11-28 | 2021-05-28 | Commissariat Energie Atomique | Procédé de traitement d’une piece metallique specifique en vue d’ameliorer sa resistance a la corrosion et ses proprietes d’adhesion a une composition de revetement, telle qu’une peinture |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102352501B (zh) | 2011-10-09 | 2013-09-04 | 上海大学 | 一种钢铁表面形成缓蚀膜的方法 |
FR3014116A1 (fr) * | 2013-12-04 | 2015-06-05 | Commissariat Energie Atomique | Primaire d'adherence pour peinture |
-
2017
- 2017-12-07 WO PCT/EP2017/081903 patent/WO2018114371A1/de unknown
- 2017-12-07 EP EP17829612.5A patent/EP3559313A1/de not_active Withdrawn
Also Published As
Publication number | Publication date |
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WO2018114371A1 (de) | 2018-06-28 |
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