EP3044348A1

EP3044348A1 - Treatment solution containing chromium(iii) for a method for producing an anti-corrosion coating layer, concentrate of such a treatment solution, and method for producing an anti-corrosion coating layer

Info

Publication number: EP3044348A1
Application number: EP14771781.3A
Authority: EP
Inventors: Thomas Nitzsche; Julian Hoffmann
Original assignee: Hillebrand Chemicals GmbH
Current assignee: Hillebrand Chemicals GmbH
Priority date: 2013-09-13
Filing date: 2014-09-15
Publication date: 2016-07-20
Anticipated expiration: 2034-09-15
Also published as: HRP20220130T1; DE102013015113A1; HUE058902T2; DE202013010956U1; CY1124966T1; EP3044348B1; ES2905136T3; DK3044348T3; WO2015036124A1; PT3044348T

Abstract

The invention relates to a treatment solution for a method for producing an anti-corrosion coating layer on a metal surface, wherein the surface to be treated is brought in contact with a treatment solution, which contains a chromium(III) ion source, a phosphate source, a zinc ion source, and a citrate source, wherein the amount-of-substance ratio of chromium(III) ions to zinc ions is 1 to at least 1.65 and the amount-of-substance ratio of chromium(III) ions to citrate is 1 to at least 1.4 and the treatment solution is substantially free of polymers that can be obtained by reacting one or more alkoxysilanes of the formula: R4-xSi(OR1)x, wherein the groups R are the same or different from each other and each represent a substituted or unsubstituted hydrocarbon group having 1 to 22 hydrocarbon atoms, x is equal to 1, 2, or 3, and R1 stands for a substituted or unsubstituted hydrocarbon group having 1 to 8 hydrocarbon atoms, and one or more alkoxides of the formula: Me(OR2)n, wherein Me stands for Ti, Zr, Hf, Al, Si and n stands for the oxidation number of Me and R2 represents a substituted or unsubstituted hydrocarbon group having 1 to 8 hydrocarbon atoms.

Description

CHROME (III) DENTAL TREATMENT SOLUTION FOR A METHOD OF GENERATING ONE

The present invention relates to a processing solution for a method for producing a corrosion-protective coating layer, a concentrate of such a processing solution, and a method for producing a corrosion-protective coating layer. Practical methods for producing a corrosion-protective coating layer on a metallic surface are known in which the surface to be treated is brought into contact with a treatment solution.

In order to achieve a sufficient corrosion protection and / or sufficient functional properties, predominantly multi-stage processes are used, which include a passivation, rinsing steps (cascade rinsing) and optionally a subsequent sealing. The passivation is followed by at least one rinsing step, in which the salt load required for producing an insoluble conversion layer, which would otherwise lead to reduced corrosion protection, is removed from the surface of the workpiece to be treated. Heavy metal contaminated wastewater is the result here, which must be clarified with the appropriate cost. The subsequent sealing is usually carried out in a separate system and is therefore costly.

CONFIRMATION COPY In the case of single-stage processes either insufficient corrosion protection is to be achieved or the use of film-forming polymers is required. Film-forming polymers, ie those which are used for surface filming, however, tend to stick, whereby these methods are not suitable for all geometric shapes of bulk goods or for coil coatings. In addition, the use of film-forming polymers leads to inhomogeneities within the coating layer and thus to reduced barrier action of the corrosion-protective coating layer. DE 196 38 176 A1 describes a chromium (VI) -free passivation layer on metal surfaces of zinc, cadmium, aluminum or alloys thereof and a process for their preparation. Chromium (III) complexes are used in the generation of the passivation layer. In a conventional passivation such as according to DE 196 38 176 A1, a pH of the treatment solution of less than 3 is implicit. The skilled person was in fact no other way available to prevent the undesirable precipitation of chromium ions as chromium hydroxides. Such a low pH strongly activates the surface of the metal substrate which will continue to react even after the termination of dipping. During drying, salts form, some of which contain water of crystallization. It comes after a short time to corrosion losses.

WO 201 1/000969 A1 discloses a method for corrosion treatment for surfaces of zinc and zinc alloys. In this case, an aqueous treatment solution of chromium (III) ions and phosphate is used. Here, silanes of a specifically defined type are used. It is to be assumed that the treatment solution contains micro- or even macroscopic organic particles which shorten the service life of the coating bath and / or lead to a reduction in quality on the surface of the workpiece.

The method of EP 2 014 793 A2 for corrosion treatment is based on the use of a conversion layer on which the coating layer is produced.

Also JP-2005-023372 A discloses a method for producing a chromium (III) -containing protective layer. This, too, is based on the use of a conversion layer on which the coating layer is produced.

It is therefore an object of the present invention to provide an effective corrosion protection on metallic surfaces. In particular, a versatile applicable method is to be made available, which preferably in one stage - ie without subsequent rinsing steps and optionally separate Versieglung - and in a Variety of metallic surfaces containing, for example, aluminum, magnesium, nickel, cadmium, zinc, tin, manganese, magnesium and / or their alloys, can be used. Furthermore, a treatment solution for such a method should be proposed and a concentrate of such a treatment solution.

This object is achieved by the treatment solution according to claim 1, the concentrate according to claim 11 and the method according to the independent claims 12 and 13. Advantageous embodiments are the subject of corresponding subclaims and the following description.

On the one hand, the invention is based on the recognition that the avoidance of the silanes specifically described in WO 2011/000969 A1 in the treatment solution also prevents their entry into the coating layer to be produced. It has been recognized that silanes of this type can lead to pores and defects in the coating layer and thus reduce the quality of the coating layer to be produced. Because the use of silanes of WO 2011/000969 A1 is dispensed with, the dried corrosion-protective coating layer has a more homogeneous structure and, through improved barrier action, inhibits the diffusion of attacking agents to an increased extent.

It has been found that the corrosion-protective coating layer produced by the process according to the invention has a low degree of redissolution in aqueous media when dried. Furthermore, it shows a surprisingly high degree of flexibility, which avoids cracks and breaks in movements of the metallic surface. Surprisingly, according to the invention, disadvantages of the conventional passivation processes can be avoided, namely that insufficient sagging properties are achieved during drying and thus the salts (containing water of crystallization) greatly reduce the corrosion protection and contaminate any subsequent solvent-based coating media and irreversibly damage them. Rather, according to the invention, a sealing layer can be achieved which makes subsequent rinsing steps unnecessary, so that excellent corrosion protection can be achieved and negative effects on subsequent coating media, in particular water entry in solvent-containing coating media, can be avoided.

The corrosion-protective coating layer applied according to the invention combines the functionalities of a passivation layer containing chromium (III) ions and a high-grade sealing layer. The inventive method allows passivation and sealing in a treatment step without subsequent rinsing steps. It has been found that the appearance of the treated metallic surface does not change or only to a slight extent during long-term corrosive loading. Since silanes, as well as those mentioned in WO 2011/000969 A1 in the neutral or alkaline pH range show a strong tendency to coagulation, the storage stability of the treatment solution is significantly improved by dispensing with the silanes of WO 2011/000969 A1. The stability in the alkaline also allows the use of a base solution according to the invention as an alkaline assistant in coating compositions.

The invention also allows the abandonment of the use of toxic and environmentally hazardous chromium (VI) ions. It has also been found that the treatment solution according to the invention is stable to friction-adjusting additives, ie lubricants, and other functionally required components.

definitions

For the purposes of the present invention, a "treatment solution" may be an aqueous solution, ie one which predominantly contains water as solvent The treatment solution may also be a nonaqueous one, which contains predominantly at least one organic solvent as solvent. The proportion of water in the total solvent is preferably more than 50% by weight, preferably more than 65% by weight, more preferably more than 80% by weight and more preferably more than 90% by weight By contrast, if the treatment solution is a nonaqueous solution, the proportion of water in the total solvent is less than 5% by weight, preferably 1 to 3% by weight.

A "chromium (III) ion source" in the present invention means at least one compound which releases chromium (III) ions, preferably in complexed form, in the treatment solution. The term "phosphate source" in the sense of the present invention is at least a compound which releases phosphate in the treatment solution.

A "zinc ion source" in the context of the present invention is at least one compound which liberates zinc ions in the treatment solution, preferably in complexed form. In the present invention, "citrate source" means at least one compound that releases citrate in the treatment solution.

The term "phosphate" in the present invention in particular stands for unprotonated ortho-phosphate, monoprotic ortho-phosphate (hydrogen phosphate) as well as doubly protonated orthophosphate (dihydrogen phosphate) and ortho-phosphoric acid.

In the present invention, the term "citrate" includes in particular unprotonated, singly protonated and doubly protonated citrate and citric acid.

A "lubricant" in the sense of the present invention describes a dispersion of micronized particles which reduce the frictional resistance of two contact surfaces which move relative to one another and preferably can set a defined coefficient of friction, in particular the lubricant has no filming properties.

The term "metallic surface" in the present invention also encompasses those surfaces of metal to which one or more non-metallic organic and / or inorganic coatings, in particular a conversion layer, have already been applied.

By "silanes of WO 2011/000969 A1" in the present invention, those polymers are understood which by reaction

- One or more alkoxysilanes of the formula R _4-x Si (OR ¹ ) _x wherein the radicals R are the same or different and each represents a substituted or unsubstituted hydrocarbon group having 1 to 22 hydrocarbon atoms, x is 1, 2 or 3 and R is ^{1 represents} a substituted or unsubstituted hydrocarbon group having 1 to 8 carbon atoms, and

- One or more alkoxides of the formula Me (OR ² ) _n wherein Me is Ti, Zr, Hf, Al, Si and n is the oxidation state of Me and R ^{2 represents} a substituted or unsubstituted hydrocarbon group having 1 to 8 carbon atoms, are available , As the "molar ratio", the ratio of the relative amount of the one substance in the treating solution in mols of the material / kg of the treating solution to the relative Quantity of another substance in the treatment solution in moles of the substance / kg treatment solution understood.

Further description of the invention

The treatment solution according to the invention contains a chromium (III) ion source, a phosphate source, a zinc ion source and a citrate source. The molar ratio of chromium (III) ions to zinc ions is 1: at least 1.65 and the molar ratio of chromium (III) ions to citrate is 1: at least 1.4. Thus, the molar ratio of chromium (III) ions to zinc ions is at most 0.61 and the molar ratio of chromium (III) ions to citrate is at most 0.72. Thus, the mole fraction of zinc ions over the mole fraction of chromium (III) ions by at least 1.65 times and the mole fraction of citrate over the mole fraction of chromium (III) ions outweighs at least 1.4 times.

The treatment solution is also substantially free of silanes of WO 2011/000969 A1. "Substantially free of silanes of WO 2011/000969 A1" means that the treatment solution is less than 10 g / l, preferably less than 5 g / l, more preferably less than 1 g / l and particularly preferably less than 0.1 contains g / l of silanes of WO 2011/000969 A1 Particularly preferably, the treatment solution contains no silanes of WO 2011/000969 A1.

The chromium (III) ion source contained in the treatment solution is preferably selected from the group consisting of inorganic chromium (III) salts, chromium (III) salts of organic acids and chromium (VI) compounds, from which chromium ( III) ions, preferably in complexed form, can be generated in situ, and mixtures of these. Particular preference is given to using chromium (VI) compounds.

Suitable inorganic chromium (III) salts are, for example, basic chromium (III) sulfate, chromium (III) hydroxide, chromium (III) dihydrogen phosphate, chromium (III) chloride, chromium (III) nitrate, potassium chromium (III) Sulfate and mixtures of these. Preference is given to using chromium (III) hydroxide, chromium (III) dihydrogen phosphate, chromium (III) nitrate or potassium chromium (III) sulfate.

Suitable chromium (III) salts of organic acids are, for example, chromium (III) -

Methanesulfonate, chromium (III) citrate, chromium (III) tartrate, chromium (III) acetate and mixtures of these. Suitable chromium (VI) compounds for the in situ generation of chromium (III) ions are, for example, chromium (VI) oxide, chromates such as potassium or sodium chromate, dichromates such as potassium or sodium dichromate, and mixtures of these. Suitable reducing agents for generating chromium (III) ions in situ are, for example, sulfites such as sodium sulfite, sulfur dioxide, phosphites, hypophosphites such as sodium hypophosphite, phosphorous acid, hydrogen peroxide, alcohols such as methanol, hydroxycarboxylic acids, hydroxydicarboxylic acids such as gluconic or malic acid, citric acid, and mixtures of this.

Preferably, the phosphate source contained in the treatment solution is selected from the group consisting of ortho-phosphoric acid, pyrophosphoric acid, meta-phosphoric acid, polyphosphoric acid and their salts in all possible protonation stages, oV-phosphorus pentoxide and mixtures of these. Ortho-phosphoric acid is particularly preferably used.

The zinc ion source contained in the treatment solution is preferably a zinc salt. Suitable zinc salts are, for example, zinc sulfate, zinc chloride, zinc phosphate, zinc oxide, zinc hydroxide, zinc citrate and mixtures of these. Zinc oxide or zinc phosphate is particularly preferably used.

The citrate source contained in the treatment solution is preferably selected from the group consisting of citric acid and salts of citric acid, ie salts with unprotonated, singly or doubly protonated citrate.

Suitable salts of citric acid are monosodium urate, disodium citrate, trisodium citrate, ammonium citrate and potassium citrate.

The phosphate concentration in the treatment solution is preferably between 1 g / l and 110 g / l, more preferably between 5 g / l and 50 g / l and particularly preferably between 10 g / l and 35 g / l (calculated as orthophosphate). ,

The treatment solution preferably has a molar ratio of chromium (III) ions to phosphate of between 1: 1, 5 and 1: 5, preferably between 1: 2 and 1: 4.5 and more preferably between 1: 3 and 1: 4.

In a preferred embodiment, the molar ratio of chromium (unions to zinc ions in the treatment solution is between 1: 1, 65 and 1: 2.35, preferably between 1: 1, 75 and 1: 2.25, more preferably between 1: 1, 85 and 1: 2.15 and more preferably about 1: 2. In a preferred embodiment, the molar ratio of chromium (III) ions to citrate is in the treatment solution between 1: 1, 4 and 1: 1, 8, preferably between 1: 1, 45 and 1: 1, 75, more preferably between 1: 1, 5 and 1: 1, 7 and particularly preferably at about 1: 1, 6th More preferably, the molar ratio of chromium (III) ions to zinc ions in the treatment solution is adjusted to the molar ratio of chromium (III) ions to citrate, such that the molar ratio of chromium (III) ions to zinc ions is between 1: 1.65 and 1: 2.35 and that of chromium (III) ions to citrate is between 1: 1, 4 and 1: 1.8, preferably the molar ratio of chromium (III) ions to zinc ions is between 1: 1, 75 and 1: 2.25 and that of chromium (III) ions to citrate is between 1: 1, 45 and 1: 1, 75, more preferably the molar ratio of chromium (III) ions to zinc ions is between 1: 1, 85 and 1: 2.15, and that of chromium (III) ions to citrate is between 1: 1.5 and 1: 1: 7, and more preferably the molar ratio of chromium (III) ions to zinc ions is about 1: 2 and that from chromium (III) ions to citrate is about 1: 1, 6. In a particularly preferred embodiment, the concentration of zinc ions in the treatment solution is calculated from the concentration of the chromium (III) ions in the treatment solution according to the following formula 1:

In a particularly preferred embodiment, the concentration of the citrate in the treatment solution is calculated from the concentrations of the chromium (III) ions and the zinc ions in the treatment solution according to the following formula 2:

"[Mol] I Imol] ² " ίτηοΙ "" ΧπιοΙΛ "[π οϊ \

(2)

Figure 1 is illustrative of the concentration ratios resulting from the use of formula (1) and formula (2). The concentration ratios correspond to the length ratios of the respective lines of the triangle shown.

The concentration of the chromium (III) ions in the treatment solution is preferably between 0.2 g / l and 27 g / l, preferably between 0.2 g / l and 20 g / l, more preferably between 0.5 g / l and 15 g / l, and more preferably between 1 g / l and 10 g / l. Preferably, the concentration of zinc ions in the treatment solution is between 0.5 and 66 g / l, preferably between 0.5 and 49 g / l, more preferably between 1, 2 and 37 g / l and particularly preferably between 2.5 and 25 g / l. Preferably lies the concentration of citrate in the treatment solution is between 1.1 and 154 g / l, preferably between 1.1 and 14 g / l, more preferably between 2.8 and 85 g / l and particularly preferably between 5.7 and 57 g / l. In a preferred embodiment, the concentrations of the chromium (III) ions, the zinc ions and the citrate in the treatment solution are coordinated so that the concentration of chromium (III) ions is between 0.2 and 27 g / l, that of the zinc ions between 0.5 and 66 g / l and that of the citrate is between 1.1 and 154 g / l, preferably the concentration of the chromium (III) ions between 0.2 and 20 g / l, that of the zinc ions between 0, 5 and 49 g / l and that of the citrate is between 1.1 and 114 g / l, more preferably the concentration of chromium (III) ions between 0.5 and 15 g / l, that of the zinc ions between 1.2 and 37 g / l and that of the citrate is between 2.8 and 85 g / l and particularly preferably the concentration of the chromium (III) ions between 1 and 10 g / l, that of the zinc ions between 2.5 and 25 g / l and that of the citrate is between 5.7 and 57 g / l. The combinations # 1 to # 48 of the individual molar ratio ranges listed in Table 1 below are embodiments according to the invention:

Table 1:

Combination of chromium (III) ions to chromium (III) ions to chromium (III) ions

Zinc-ion citrate phosphate

# 1 1 1.65 to 1.135 1 1.4 to 1: 1.8 1 1.5 to 1: 5

# 2 1 1, 65 to 1 2.35 1 1.4 to 1: 1.8 1 2 to 1: 4.5

# 3 1 1.65 to 1.135 1 1.4 to 1: 1.8 1 3 to 1: 4

# 4 1 1.65 to 1.135 1.45 to 1: 1.75 to 1.5 to 1: 5

# 5 1 1.65 to 1.355 1.45 to 1: 1.75 1 2 to 1: 4.5

# 6 1 1.65 to 1.135 1.45 to 1: 1.75 1 3 to 1: 4

# 7 1 1.65 to 1.135 1 1.5 to 1: 1: 7 1 1.5 to 1: 5

# 8 1 1.65 to 1.135 1 1.5 to 1: 1: 7 1 2 to 1: 4.5

# 9 1 1.65 to 1.135 1 1.5 to 1: 1: 7 1 3 to 1: 4

# 10 1 1.65 to 1.35 about 1: 1.6 1 1.5 to 1: 5

# 11 1 1.65 to 1.35 about 1: 1.6 1 2 to 1: 4.5

# 12 1 1.65 to 1.35 about 1: 1.6 1 3 to 1: 4

# 13 1 1.75 to 1.225 1 1.4 to 1: 1.8 1 1.5 to 1: 5

# 14 1 1.75 to 1.225 1 1.4 to 1: 1.8 1 2 to 1: 4.5

# 15 1 1.75 to 1.225 1 1.4 to 1: 1.8 1 3 to 1: 4

# 16 1 1.75 to 1.25 1.45 to 1: 1.75 to 1.5 to 1: 5

# 17 1 1.75 to 1.25 1.45 to 1: 1.75 1 2 to 1: 4.5

# 18 1 1.75 to 1.25 1.45 to 1: 1.75 to 3: 1 to 1: 4

# 19 1 1.75 to 1.25 1.15 to 1: 1: 7 1 1.5 to 1: 5

# 20 1 1.75 to 1.25 1.15 to 1: 1: 7 1 2 to 1: 4.5 # 21 11.75 to 12.25 1: 1.5 to 1: 1: 7 13 to 1: 4

# 22 1 1.75 to 1.25 about 1: 1.6 1 1.5 to 1: 5

# 23 1 1.75 to 1.25 about 1: 1.6 1 2 to 1: 4.5

# 24 1 1.75 to 1.25 about 1: 1.6 1 3 to 1: 4

# 25 1 1.85 to 1 2.15 1 1.4 to 1: 1.8 1 1.5 to 1: 5

# 26 1 1.85 to 1. 2.15 1 1.4 to 1: 1.8 1 2 to 1: 4.5

# 27 1 1.85 to 1 2.15 1 1.4 to 1: 1.8 1 3 to 1: 4

# 28 1 1.85 to 1.155 1.45 to 1: 1.75 to 1.5 to 1: 5

# 29 1 1.85 to 1.155 1.45 to 1: 1.75 1 2 to 1: 4.5

# 30 1 1.85 to 1.155 1.45 to 1: 1.75 1 3 to 1: 4

# 31 1 1.85 to 1 2.15 1 1.5 to 1: 1: 7 1 1.5 to 1: 5

# 32 1 1.85 to 1.22.15 1.5 to 1: 1: 7 1 2 to 1: 4.5

# 33 1 1.85 to 1.155 1.5 to 1: 1: 7 1 3 to 1: 4

# 34 1 1.85 to 1 2.15 about 1: 1.6 1 1.5 to 1: 5

# 35 1 1.85 to 1 2.15 about 1: 1.6 1 2 to 1: 4.5

# 36 1 1.85 to 1. 2.15 about 1: 1.6 1 3 to 1: 4

# 37 about 1 2 1 1.4 to 1: 1.8 1 1.5 to 1: 5

# 38 about 1 2 1 1.4 to 1: 1.8 1 2 to 1: 4.5

# 39 about 1 2 1 1.4 to 1: 1.8 1 3 to 1: 4

# 40 about 1 2 1 1.45 to 1: 1.75 1 1.5 to 1: 5

# 41 about 1 2 1 1.45 to 1: 1.75 1 2 to 1: 4.5

# 42 about 1 2 1 1.45 to 1: 1.75 1 3 to 1: 4

# 43 about 1 2 1 1.5 to 1: 1: 7 1 1.5 to 1: 5

# 44 about 1 2 1 1.5 to 1: 1: 7 1 2 to 1: 4.5

# 45 about 1 2 1 1.5 to 1: 1: 7 1 3 to 1: 4

# 46 about 1 2 about 1: 1.6 1 1.5 to 1: 5

# 47 about 1 2 about 1: 1.6 1 2 to 1: 4.5

# 48 about 1 2 about 1: 1.6 1 3 to 1: 4

Preferably, the treatment solution additionally contains at least one surfactant, preferably at least one nonionic, anionic or amphoteric surfactant, or more preferably a combination thereof, such as a combination of a nonionic with an anionic surfactant, a combination of a nonionic with an amphoteric surfactant, a combination of an anionic with an amphoteric surfactant or a combination of a nonionic, an anionic and an amphoteric surfactant. The addition of surfactants can promote film formation of the treatment solution on the metallic surface to be treated.

The total concentration of surfactant is preferably between 0.01 and 30 g / l, preferably between 0.1 and 15 g / l, more preferably between 0.2 and 8 g / l and more preferably between 0.3 and 3 g / l. The term "total concentration of surfactant" is understood to mean the ratio of the sum of the weights of the surfactants present in the treatment solution to the volume of the treatment solution In a preferred embodiment, the treatment solution contains at least one nonionic and at least one anionic surfactant in a mass ratio of 4: 1 to 1: 8, preferably from 2: 1 to 1: 6, more preferably from 1: 1 to 1: 4, and most preferably from 1: 1 to 1: 2. In another preferred embodiment, the treatment solution contains at least one nonionic, at least one anionic and at least one amphoteric surfactant in a mass ratio of 1: 1: 1 to 1: 5: 1, preferably from 1: 2: 1 to 1: 4: 1 and more preferably from about 1: 3: 1. Preferred nonionic surfactants Alkyloxethylates such as Lutensol® ON 50 (BASF), alkyl polyglucosides such as Triton ™ CG-110 (Dow Chemicals), polyalkylene glycol ethers, Guerbet alcohol alkoxylates such as Lutensol® XL 40 (BASF), Fe t-aminoethoxylates and mixtures of these. Preferred anionic surfactants are fatty alcohol poly (oxyethylene) sulfonates such as Ralufon® F 11-13 (Raschig), arylsulfonates such as K-Na cumene sulfonate, fatty alcohol sulfates, alkyl carboxylates, alkylbenzenesulfonates and mixtures of these.

Preferred amphoteric surfactants are alkyl betaine, dipalmitoyl lecithin and mixtures of these.

Particular preference is given to using one of the surfactant combinations listed in Table 2 below:

Table 2:

nonionic surfactant anionic surfactant amphoteric mass ratio

surfactant

Alkyloxethylate Fatty alcohol poly (oxy- - 1: 2

ethylene) sulfonate

Alkyloxethylate + fatty alcohol poly (oxy- - 1: 1, 2

Alkylpolyglucoside ethylene) sulfonate

Alkyloxethylate arylsulfonate 1: 2

Alkyl polyglucoside fatty alcohol sulfate - 1: 1

Polyalkylene glycol ether Alkylcarboxylate - 1: 5

Guerbet alcohol alkoxylate aryl sulfonate - 2: 1 Fatty amino ethoxylate alkyl benzene sulfonate alkyl betaine 1: 3: 1

- - Alkyl Betaine -

- - dipalmitoyl lecithin -

In a preferred embodiment, the aqueous treatment solution additionally contains at least one organophosphate and / or organophosphonate. This can lead to a higher degree of crosslinking of the corrosion-protective coating layer produced and thus to improved corrosion-protecting properties.

The aqueous treatment solution preferably contains at least one organophosphonate, preferably at least one amino phosphonate.

Preferred aminophosphonates here are aminotris (alkylphosphonic acid) having a chain length of C1 to C8 for the alkyl group, dimethylaminoethanediphosphonic acid (DMAEDP), 1-aminoethanediphosphonic acid (AEDP), diethylenetriaminepenta (methylenephosphonic acid) (DTPMP), ethylenediamine-tetra (methylenephosphonic acid) (EDTMP) , Hydroxyethyl-amino-di (methylenephosphonic acid) (HEMPA) and mixtures of these.

The total concentration of aminophosphonate is preferably between 0.05 g / l and 8 g / l, preferably between 0.1 g / l and 5 g / l and more preferably between 0.3 g / l and 3 g / l and am most preferably between 0.4 g / l and 1.5 g / l.

In the prior art, the incorporation of polymers into the anticorrosive coating layer leads to a reduced barrier effect and thus also to a reduced corrosion protection of the coating layer. The latter is also due to the fact that the cathodic partial reaction of corrosion is less inhibited. In order to ensure effective corrosion protection, therefore, in the prior art, the passivation step is usually followed by a sealing step.

Surprisingly, it has now been found in the present invention that it is possible to produce a corrosion-protective coating layer which is substantially free of polymers. This can be achieved by using a treatment solution which is substantially free of certain polymers and copolymers soluble in water and / or organic solvents. "Substantially free of" means that the treating solution is less than 10 g / l, preferably less than 5 g / l, more preferably less than 1 g / l, and most preferably less than 0.1 g / l of the corresponding polymers or copolymers contains. These polymers and copolymers are in particular so-called film-forming polymers, ie those which promote the film formation of the corrosion-protective coating layer and therefore also incorporate into the layer under the selected reaction conditions, which leads to barrier imperfections in the latter. They are usually directly applied to the treatment solution added as a powder or as a preliminary solution.

Most preferably, the treatment solution is substantially free of filming polymers.

Silanes in particular are suitable for this purpose and should preferably be avoided according to the invention. Therefore, the treatment solution is preferably not only substantially free of silanes of WO 201/000969 A1 but also substantially free of silanes in general.

More preferably, the treatment solution is substantially free of silanes, more preferably substantially free of silanes, polyvinylpyrrolidone, polyvinyl alcohol and their copolymers, and more preferably free of silanes, polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycols, polyitaconic acids, polyacrylates and their copolymers.

In one embodiment, the anti-corrosive coating layer is a tribologically functional coating layer. The treatment solution in this case additionally contains 0.01 to 50 wt .-%, preferably 0.05 to 30 wt .-% and particularly preferably 0.1 to 15 wt .-% of at least one lubricant.

Preferred lubricants are those substances which are insoluble in water and / or organic solvents, ie insoluble in the treatment solution used, and, for example, have no filming properties due to the high melting temperatures.

The at least one lubricant is preferably selected from the group consisting of polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene (ETFE), perfluorinated polyethers (PFPE), polyvinylidene fluoride (PVDF), tetrafluoroethylene / hexafluoroethylene copolymer (FEP), perfluoroalkoxy copolymer (PFA) , Polysulfones, MoS2, WS2, TiS2, BN graphite and mirco-encapsulated lubricants.

The pH of the treatment solution can be adjusted in a range of 2 to 11, 5 and is to be adapted to the requirements, depending on the field of application and the condition of the surface. In parts to be treated with optical demands on the metal surface and to achieve the best possible Corrosion protection is preferably set a mildly acidic pH of the treatment solution. If the treatment solution is used to produce an intermediate layer for topcoat layer combinations, a lower pH below 4 lowers the application time. In case of application as anti-corrosive additive or with the addition of alkaline lubricant additives for the functionalization of the dry layer, a pH value above 7 must be set.

Before the process according to the invention is carried out, the treatment solution can be prepared by diluting a concentrate, that is to say a correspondingly higher concentration of base solution. In this case, the mass fraction of the base solution in the finished treatment solution is preferably 1 to 100%, more preferably 1 to 50%, further preferably 1 to 25%, more preferably 1 to 15% and most preferably 3 to 12%. The concentrate of a treatment solution of the present invention for a method for producing a corrosion-protective coating layer on a metallic surface in which the surface to be treated is brought into contact with a treatment solution is obtainable by withdrawing at least a part of the solvent from the treatment solution of the present invention.

The inventive method for producing a corrosion-protective coating layer on a metallic surface provides that the surface to be treated is brought into contact with the treatment solution according to the invention. The process parameters such as treatment temperature, treatment time, drying temperature and total drying time must be adapted to the requirements, depending on the field of application and the design or condition of the surface.

The treatment temperature, that is, the temperature during the contact of the treatment solution with the surface before drying, is preferably in the range of 10 to 90 ° C, preferably 15 to 80 ° C, and more preferably 25 to 60 ° C.

The treatment time, ie the time during which the treatment solution is in contact with the surface before drying, is preferably in the range from 1 s to 60 min, preferably from 5 s to 40 min, more preferably from 10 s to 30 min and particularly preferably from 20 s to 15 min.

The drying temperature, ie the temperature during the subsequent drying of the treated surface, is preferably in the range from 20 (room temperature) to 250 ° C, preferably from 50 to 200 ° C and particularly preferably from 80 to 180 ° C. It can be dried passively and / or actively. An active drying can be done by induction, infrared or hot air.

The total drying time, ie the time for active and passive drying, can vary between 10 s and 96 h.

Rinsing steps are not required according to the invention. The drying can thus take place after the treatment of the metallic surface with the treatment solution without previous rinsing steps.

The anticorrosive coating layer produced according to the invention can serve both as a cover layer and on the other hand as an intermediate layer (intermediate barrier or vapor barrier and / or adhesion-promoting layer) both on metal-containing layers protecting the substrate cathodically and on full metal ware. In addition, it can also act as a modification of the surface of m-scaled metal particles.

The metallic surface can be suitably preconditioned in this case. A suitable preconditioning is in particular the activation of the metallic surface by contacting it with a highly dilute acid by water acid, coordinated acid combinations or salts of suitable acids.

Furthermore, the metallic surface may have a conversion layer. According to the invention, a "conversion layer" is preferably understood as meaning a layer which is formed by a chemical reaction of a (especially aqueous) treatment solution with a metal substrate The conversion layer is preferably a chromium (III) -containing conversion layer Such conversion layers can be produced, for example, with GC Multipass and DDPass (both products of Hillebrand Chemicals GmbH).

If the metallic surface to be treated has a conversion layer, the treatment solution according to the invention is used as a night dip solution and the process according to the invention thus leads to a further improved corrosion protection. The corrosion-protective coating layer according to the invention serves in this case as a seal with post-passivation properties and can also act as an additional primer for further layer structures. In a preferred embodiment, the metallic surface does not have a conversion layer.

Since, according to a preferred embodiment of the method according to the invention, the aggressiveness of the mechanism of action, as opposed to a passivation, is much lower, prolonged contact of the metallic surface with the treatment solution does not lead to overpassivation (redissolution of the passivation layer) and thus to loss of corrosion protection. The salt load on the surface dries to a barrier dense layer and is therefore not disturbing.

The present invention thus also provides a process for producing a corrosion-protective coating layer on a metallic surface, wherein the surface to be treated has no conversion layer, the passivation and sealing of the surface to be treated takes place in one step and without rinsing step between them, and the coating layer formed in Essentially free of silanes of WO 2011/000969 A1.

In a preferred embodiment, the metallic surface to be treated is a material applied to a steel substrate which has a base electrochemical potential relative to the steel substrate.

In a preferred embodiment, the surface to be treated is a cathodic protective metallic surface.

More preferably, the metallic surface to be treated is one selected from the group consisting of

the surface of a galvanically deposited layer containing zinc or a zinc alloy, preferably ZnFe, ZnCd, ZnSn, ZnSnCu or ZnNi, with or without already implemented conversion layer,

hot-dip galvanized surfaces, preferably containing zinc or a zinc alloy,

the surface of a flame-sprayed layer, preferably containing zinc, a zinc alloy, aluminum or an aluminum alloy, the surface of a layer produced by thermal diffusion method (sheradizing),

the surface of a mechanically applied cathodically protective layers, preferably mechanically galvanized surfaces,

a zinc die-cast surface, preferably containing a zamak alloy, preferably ZL0400, ZL0410 or ZL0430,

a clad aluminum surface, a full metal surface, preferably containing zinc, aluminum, magnesium or an alloy of zinc, aluminum or magnesium with preferred trace elements

the surface of pm-scaled metal particles, preferably containing zinc, aluminum, magnesium, manganese, tin, nickel, iron, molybdenum, vanadium,

Copper and / or their alloys and

the surface of a metal dispersion dry layers (MDTS), preferably containing zinc, aluminum, manganese, copper, tin, nickel, iron, molybdenum, vanadium and / or magnesium, as well as silicon, titanium and / or zirconium. Preferably containing zinc and aluminum, as well as titanium, silicon and zirconium.

In a preferred embodiment, the metallic surface is the surface of a tape product. Exemplary applications on such cathodically protective metallic surfaces and the process parameters used are listed below: i) Galvanically deposited zinc or zinc alloy layers

Bulk or racked goods, coated with electrodeposited layers of zinc or zinc alloy layers such as ZnFe, ZnSn, ZnMn, ZnCd, ZnNi and ternary systems, can be immersed in the treatment solution according to the invention to increase the corrosion protection. To produce passivating topcoats with sealing character, the treatment solution is preferably adjusted to a pH of 4 to 5 and the product is preferably dried actively at 80 ° C for 10 min. The cover layer produced has no adhesion tendency, which leads to very good coating results, in particular when applied to bulk goods. Surface areas with extreme wet film thickness of the processing solution will dry without the appearance of feed to a flexible film.

If the treatment solution is used as a corrosion-protective intermediate barrier or vapor barrier and / or adhesion-promoting layer for sealants or topcoats, the pH can be lowered to values up to pH 3, resulting in a shorter treatment time and / or a greater passivation effect. ii) hot dip galvanizing

For application to hot-dip galvanized surfaces of pure zinc or zinc alloys, the treatment solution according to the invention is preferably adjusted to a pH of 3 to 6. Due to a lower pH of the treatment solution, the Treatment temperature can be reduced to room temperature, which can be saved especially in large bath surfaces energy. If the hot, already quenched hot-dip galvanized product is brought into contact with the treatment solution, forms by reactivity of the active substances, a closed layer which dries by residual heat of the part body without additional energy. iii) flame spray coatings

Zinc or aluminum surfaces applied by flame spraying can preferably be treated with the treatment solution according to the invention at pH values between 3 and 6. The process-related residual heat can also be used here for complete drying of the aftertreatment layer. iv) thermal diffusion galvanizing

Another field of application of the treatment solution according to the invention is the coating of thermodiffusion-galvanized surfaces. Due to the combination of passivation and sealing, there is the advantage that, despite the high iron content of the diffusion layer, the punctual red rust breakthroughs, which typically occur early, can be prevented for a long time. Bulk products can be easily treated because of the universal applicability of the passivation solution.

Over a particularly wide pH value interval for setting the process chemistry, different layer properties on thermodiffusion zinc are made possible. For example, by setting a mild pH of 4 to 5, the original surface coloration can be maintained whereas a pH of 2.5 to 3.5 produces dark layers. v) Mechanical galvanizing

Mechanically galvanized product is coated to increase the corrosion by means of the treatment solution according to the invention preferably in the pH range of 4.3 to 4.6. This preserves the typical surface color. By lowering the pH to below 4, dark layers can be achieved. Bulk products which are typical of this process can be easily coated and dried or dried at room temperature without sticking to the product. vi) metal dispersion dry layers

The method according to the invention is also suitable for the treatment of metal goods which have metal dispersion dry layers (MDTS). MDTS typically have a layer thickness of 5 to 25 pm. MDTS can be produced on metallic surfaces by bringing the surface to be treated into contact with a special dispersion and then drying. The dispersion contains an organic and / or inorganic binding matrix and pm-scaled metal particles in spherical and / or lamellar form. The μιη-scaled metal particles are zinc, aluminum, magnesium, manganese, tin, nickel, iron, molybdenum and / or vanadium and / or particles, which consist of an alloy of said metals. The pm-scaled metal particles can also contain the least amounts of rare earths or their alloys.

The treated metal goods preferably consist of materials which have an electrochemically nobler potential than the MDTS surrounding them. Modern MDTS can be present as a metallic silver as well as a dark gray to black surface.

On the one hand, the treatment solution can be applied to an untreated, clean MDTS. The coating layer obtained after drying then acts at the same time as a layer-forming passivation and anticorrosive covering layer, preferably with sealing properties. Tribological properties can also be adjusted by lubricants integrated in the anti-corrosive coating layer. An optional black colored treatment solution supports the look of black MDTS. For optically superior parts with MDTS, the treatment solution should not be applied at a pH below 4.4. In the case of use as a passivating top layer, the treatment solution therefore has a mild pH, preferably between 4 and 1.5, preferably between 4.5 and 10 and particularly preferably between 5 and 7.5.

On the other hand, the anticorrosive coating layer can also be used as adhesion-promoting intermediate layer, in particular as passivation and vapor barrier for further organic and / or inorganic topcoats. A lower pH of the treatment solution in this case reduces the treatment time. In the case of use as passivating intermediate sealant, the treatment solution thus has an acidic pH preferably between 2 and 7, preferably between 3 and 6 and particularly preferably between 3.5 and 5.

In the treatment of MDTS, the temperature is preferably in the range of 15 to 80 ° C, preferably 25 to 60 ° C. The treatment time is preferably in the range of 1 second to 5 minutes, preferably 5 seconds to 3 minutes, more preferably 10 seconds to 2 minutes and more preferably from 20 to 90 seconds. The drying temperature is preferably in the range of 80 to 180 ° C. The total drying time is preferably in the range from 5 minutes to 96 hours, preferably from 5 minutes to 3 hours and particularly preferably from 10 minutes to 30 minutes.

In a further embodiment, the treatment solution according to the invention is used for coating metallic materials preferably consisting of zinc, aluminum, manganese, magnesium, tin, silicon and their alloys to increase the corrosion protection, optimize the overall process and / or adjust the functional properties.

In this case, the metallic surface is preferably selected from the group consisting of solid metal surfaces, preferably containing zinc, aluminum, magnesium or an alloy of zinc, aluminum and / or magnesium with preferred trace elements, zinc die-cast surfaces, preferably containing a zamak alloy, preferably ZL0400, ZL0410 or ZL0430, surfaces of μηι scaled metal particles and clad aluminum surfaces.

The following are some examples of applications on metallic materials with the corresponding process parameters: i) solid metal parts

The treatment solution according to the invention is used, for example, on fully metallic surfaces of zinc or zinc alloys, of aluminum or aluminum alloys with silicon, manganese, magnesium and / or copper and of magnesium or magnesium alloys with aluminum, zinc, manganese, silicon and / or zirconium for optical and / or surface modification.

If the layer applied by means of the treatment solution serves as a primer or anticorrosive intermediate barrier, the treatment solution is preferably used with a pH below 3.5. To produce anticorrosion and / or functional overcoats, the treatment solution is adjusted to a preferred pH of just over 4. ii) zinc-coated castings

Zinc die-castings, preferably of zamak alloys such as ZL0400, ZL0410 and ZL0430, both as drumware and in basket application, are dipped in the treatment solution and either dried or dried at room temperature. By setting the treatment solution to a pH of 3.5 to 4.2 and a temperature of over 45 ° C, a darkening of the layer can be achieved without destroying the cast skin of the component, which extreme corrosion protection loss would result. If a milder pH of 4.4 to 5 and a lower temperature of the treatment solution are set below 40 ° C, the pre-existing surface color may be retained. Particularly in the case of basket application, there is an advantage in drying over-coated areas to flexible, non-feeding films. iii) modification of rescaled metal particles

In the surface modification μηη-scaled metal particles, for example, zinc, aluminum, magnesium, manganese, tin, molybdenum, iron, nickel, copper, vanadium or their alloys, the coating layer produced by means of the treatment solution according to the invention serves as a passivation and adhesion promoter. If metal particles pretreated in this way are used in the production of a metal dispersion, there are highly positive effects with regard to the service life of the dispersion, the bonding of the modified metal particles in the binder matrix and the course of the layer corrosion.

Depending on the treatment time and temperature, the treatment solution is preferably adjusted to a pH of 2.5 to 6. A mild pH of about 5 in combination with a longer treatment time of over 4min leads to a significant improvement in terms of anchoring with the binder system used, the optics of the metal particle surface is changed in only a very small extent. iv) aluminum clad

In the surface treatment of aluminum-clad materials, it is preferable to set a pH of the treatment solution in the range of 2.5 to 6.5 for the purpose of enhancing corrosion resistance or other functional properties such as heat distribution or reflectance. In this case, optical characteristics for finalizing the surface treatment are obtained in particular by higher pH values. On the other hand, lower pH values and thus a stronger attack of the sealing passivation offer the advantage of increased adhesion for further coatings such as e.g. Industrial coatings.

Additives for sealants and topcoats

In a further embodiment, a concentrate according to the invention is used as an additive for sealants and topcoats. These are liquid and contain water and / or organic solvent as a solvent. By treating a metallic surface with a seal modified in this way or a topcoat modified in this way, it is possible to produce a more adhesive and barrier-resistant cover layer, which additionally has a passivating effect. In the language of the present application is thus the mixture of inventive concentrate with the seal, or the topcoat the treatment solution according to the invention. By definition, seals are organic and / or inorganic coatings having a dry film thickness of less than 2 μm and their solutions for the production. Topcoats form the counterpart with dry film thicknesses of over 2 pm.

A concentrate according to the invention, preferably an aqueous concentrate, is rendered alkaline, preferably added to a pH of 7.5 to 11.5, and in small amounts, preferably to 1 to 3% by volume, of a seal or a top coat. These then constitute a treatment solution in the sense of the present invention and can be used to produce a more adhesive, barrier-resistant layer with passivating properties.

As a result, the treated metallic surfaces are protected by passivation and barrier action, resulting in increased corrosion protection. The addition also increases the adhesion of the topcoat to the treated metallic surfaces.

Coating of ribbon goods

In a further embodiment, strip products with galvanically deposited layers or solid metal surfaces such as zinc, aluminum, magnesium, tin and alloys of these main constituents are finished with the treatment solution. Due to the reactive properties of the treatment solution only very short treatment times are necessary, so that at high flow speeds of the bands through the baths effective corrosion protection can be achieved.

Specific regulation possibilities arise through the adjustment of treatment temperature and pH of the treatment solution. Thus, a low pH of less than 3.5 and an elevated temperature of over 40 ° C sufficient reaction times of less than 20 s can be realized. At lower belt speeds and thus longer reaction times, a higher pH above 4 in combination with a low temperature of below 35 ° C causes less attack of the metal surface, whereby optical features are retained.

Due to the temperature resistance of the treatment solution, increased temperatures of up to 250 ° C can be used for faster drying of the surface, which can be generated by induction, infrared or hot air. Due to the low adhesive properties of the treated surfaces, the tape can be rolled up again into coils immediately after the drying process. EXEMPLARY EMBODIMENTS

The corrosion protection values in the following exemplary embodiments relate to production goods which have undergone conventional mechanical stresses. The corrosion protection values were determined in a NSS (neutral salt spray = neutral salt spray test) according to DIN EN ISO 9227. In the corrosion protection results, "WR" stands for the time until the occurrence of white rust (zinc corrosion) and "RR" for the time until the occurrence of red rust (iron corrosion of the base metal).

Example 1: Tape application

As a treatment solution, an aqueous solution of the following composition was used:

Using a coil coater, galvanized steel sheet was contacted with the treating solution at 30 ° C and a pH of 3.4 for 30 seconds. Subsequently, it was actively dried at about 120 ° C. for 15 s and an NSS was carried out. The following corrosion protection results resulted:

WR: 456 h

RR: 816 h

Example 2: Sealer

An aqueous base solution of the composition

Component concentration [g / l]

Cr3 + 50

P043-350

Zn2 + 120 Citrate3-280

DTPMP 5 was added to an acrylic sealant as a 1% additive. This gave a treatment solution which had the following concentrations:

Black-passivated ZnNi screws were brought into contact with the above treatment solution at room temperature and a pH of 9.5 for 25 s and only with the acrylate sealant without additive on the one hand. Subsequently, it was actively dried at about 80 ° C. for 10 min and an NSS was carried out. The following corrosion protection results resulted:

Example 3: Zinc diecasting

Zinc die-cast wicker was first degreased hot, rinsed twice, activated and rinsed twice again. Subsequently, the product was at 35 ° C and a pH dipped on 4.6 for 75 s in the treatment solution and dried at room temperature. The NSS gave the following corrosion protection result:

WR:> 504 h

Example 4: Hot dip galvanizing

The goods were first hot-dip galvanized, then quenched and dipped with a residual heat of about 70 ° C for 50 s and at a pH of 4.2 in a non-heated bath with the above treatment solution. The drying was carried out by the object temperature of the treated part. The NSS gave the following corrosion protection results:

WR: 264 h

RR: 480 h

Example 5: rescaled metal particles

25% by volume of pm-scaled metal particles were mixed with 75% by volume of the treatment solution. After 15 minutes at 35 ° C and a pH of 5, the treatment solution was decanted. It was then dried actively at 150 ° C.

Example 6: Metal dispersion dry layer I

A blasted steel surface with a 7 pm thick MDTS (lamellar zinc and aluminum particles and a titanium oxide / silica binder system) was subjected to a dip / spin application without subsequent rinse step. The steel surface was wetted for 50 s at 40 ° C and a pH of 4.4 with the treatment solution and then dried at 80 ° C for 10 min.

There was no visual change in the parts after treatment and drying. Even after removal from the NSS, there were no optical changes in the surface after 4500 h. Example 7: Metal Dispersion Dry Layer II

A blasted steel surface with a 7 pm thick MDTS (lamellar zinc and aluminum particles and a titanium oxide / silica binder system) was subjected to a dip / spin application without subsequent rinse step. The steel surface was wetted with the treatment solution for 50 s at 35 ° C. and a pH of 5.5, and then dried at 80 ° C. for 10 minutes.

There was no visual change in the parts after treatment and drying. Even after removal from the NSS, there were no optical changes in the surface after 5000 h.

Claims

"Claims"

A treatment solution for a process for producing a corrosion-protective coating layer on a metallic surface, in which the surface to be treated is brought into contact with a treatment solution which

a chromium (III) ion source,

a phosphate source,

a zinc ion source and

- a citrate source

wherein the molar ratio of chromium (III) ions to zinc ions is 1: at least 1.65 and the molar ratio of chromium (III) ions to citrate 1: at least 1.4 and the treatment solution is substantially free of polymers by reaction

- One or more alkoxysilanes of the formula R ₄ . _{x is} Si (OR ¹ ) _x wherein R is the same or different from each other and each represents a substituted or unsubstituted hydrocarbon group having 1 to 22 carbon atoms, x is 1, 2 or 3 and R ^{1 is} a substituted or unsubstituted hydrocarbon group having 1 to 8 hydrocarbon atoms, and

- One or more alkoxides of the formula Me (OR ² ) _n wherein Me is Ti, Zr, Hf, Al, Si and n is the oxidation state of Me and R ^{2 represents} a substituted or unsubstituted hydrocarbon group having 1 to 8 carbon atoms, are available ,

A treatment solution according to claim 1, wherein the molar ratio of chromium (III) ions to phosphate is between 1: 1, 5 and 1: 5, preferably between 1: 2 and 1: 4.5 and more preferably between 1: 3 and 1: 4 lies.

A treatment solution according to claim 1 or 2, wherein the molar ratio of chromium (III) ions to zinc ions is between 1: 1, 65 and 1: 2.35 and that of chromium (III) ions to citrate is between 1: 1, 4 and 1 : 1, 8 lies.

4. Treatment solution according to one of the preceding claims, wherein the concentration of zinc ions in the treatment solution from the concentration of chromium (III) ions in the treatment solution according to the formula

[kg I sin.30.5 ° and / or the concentration of citrate in the treatment solution is the concentration of the chromium (III) ions in the treatment solution and the concentration of zinc ions in the treatment solution of the formula

Citrate ^{3 '} • cos 52.5 °

calculated.

Treatment solution according to one of the preceding claims, wherein the concentration of the chromium (III) ions in the treatment solution is between 0.2 and 27 g / l, that of the zinc ions in the treatment solution between 0.5 and 66 g / l and / or that of the Citrate in the treatment solution is between 1, 1 and 154 g / l.

Treatment solution according to one of the preceding claims, wherein the treatment solution contains at least one surfactant.

Treatment solution according to one of the preceding claims, wherein the treatment solution contains at least one aminophosphonate and the total concentration of aminophosphonate is between 0.05 and 8 g / l, preferably between 0.1 and 5 g / l, particularly preferably between 0.3 and 3 g / l, and more preferably between 0.4 and 1.5.

A treatment solution according to any one of the preceding claims, wherein the treatment solution is substantially free of silanes.

Treatment solution according to one of the preceding claims, wherein the corrosion-protective coating layer is a tribologically functional coating layer and the treatment solution additionally from 0.1 to 50 wt .-%, preferably 1 to 30 wt .-%, and particularly preferably 3 to 15 wt .-% at least contains a lubricant.

Treatment solution according to one of the preceding claims, wherein the treatment solution is prepared by adding an aqueous base solution having a pH of 7.5 to 11, 5 to sealants or topcoats.

11. A concentrate of a treating solution for a method of forming a corrosion protective coating layer on a metallic surface, in which the surface to be treated is contacted with a treating solution obtainable by withdrawing at least a part of the solvent from the treating solution according to any one of claims 1 to 10 ,

12. A method for producing a corrosion-protective coating layer on a metallic surface, wherein

the surface to be treated does not have a conversion layer,

- The passivation and sealing of the surface to be treated in one step by contact of the surface to be treated with a treatment solution, preferably a treatment solution according to one of claims 1 to 10, and carried out without intervening rinsing step and

the coating layer formed is substantially free of polymers which are obtained by reaction of one or more alkoxysilanes of the formula R _4- xSi (OR ¹ ) _x where the radicals R are the same or different from each other and in each case a substituted or unsubstituted hydrocarbon radical having 1 to 22 Represent hydrocarbon atoms, x is 1, 2 or 3 and R ^{1 is} a substituted or unsubstituted hydrocarbon group having 1 to 8 carbon atoms, and

13. A method for producing a corrosion-protective coating layer on a metallic surface, wherein the surface to be treated is brought into contact with a treatment solution according to any one of claims 1 to 10.

14. Use of a treatment solution according to any one of claims 1 to 10 for producing a corrosion-protective coating layer on a metallic surface.