EP2255025B2 - Process for coating metallic surfaces with a passivating agent - Google Patents

Description

The invention relates to a process for the coating of metallic surfaces with an aqueous composition which differs from phosphating solutions, the aqueous composition and the use of the process according to the invention.

Phosphate coatings are used on a large scale as corrosion protection layers, as a forming aid and as a primer for paints and other coatings. Especially if it is used as protection for a limited time, in particular storage and then, for example. are painted, they are referred to as a pretreatment layer before painting. However, if the phosphate coating is not followed by a lacquer coating and organic coating, treatment or passivation rather than pretreatment is used. These coatings are also referred to as conversion layers if at least one cation of the metallic surface, ie the surface of the metal part, is dissolved out and used for layer construction.

Among the coating methods, the so-called "no-rinse processes" are of great importance, in particular for the very rapid coating of continuously running tapes of at least one metallic material. These bands may be sheets of small or very large width. On these tapes, a phosphate coating is applied by wetting with a phosphating solution usually directly after galvanizing, but optionally also after suitable cleaning or degreasing and after rinsing with water or an aqueous medium and optionally after activation of the metallic surface and dried. A rinse after drying The phosphate coating could adversely affect this, especially if the phosphate coating is not or only partially crystalline.

In the past, these problems were circumvented industrially by adding nickel to the phosphating solution so that it mostly contained nickel contents in the range of 0.5 to 1.5 g / L. For zinc-manganese-nickel-phosphating, zinc contents in the range of 0.6 to 3.5 g / l and manganese contents in the range of 0.4 to 2.5 g / l were usually selected.

However, the high-grade phosphating solutions and phosphate coatings contain a significant amount of zinc, manganese and nickel. In particular, nickel is to be avoided because of its toxicity and harmfulness. In addition, the unavoidable heavy metal contents in the waste water, in the phosphate sludge and in the grinding dust are disturbing. For the treatment of tapes, however, there are no methods available that ensure a high level of blank corrosion protection (corrosion protection without lacquer / primer layers), especially for zinc-rich metallic surfaces.

DE 102006052919 A1 teaches aqueous compositions for anticorrosive conversion treatment of metallic surfaces based on 5-50 g / L phosphate, 0.3-3 g / L zinc and 0.001-0.2 g / L titanium or / and zirconium in water-soluble titanium / zirconium -Links.

1. 1. für hochwertige Phosphatschichten z.B. bei Zink- oder/und Mangan-reichen Phosphatierverfahren eine vorherige Aktivierung z.B. auf Basis von Titanphosphatpartikeln oder Zinkphosphatpartikeln benötigt, damit hierauf eine hochwertige Phosphatschicht ausgebildet werden kann,
2. 2. in der Regel bei Zink-haltigen Phosphatierungen nur in einem pH-Wertbereich von 2 bis 3,5 eingesetzt werden kann,
3. 3. üblicherweise keinen Gehalt an Titan- oder/und Zirkoniumverbindungen von insgesamt mehr als 0,05 oder mehr als 0,1 g/L ohne Störungen verkraftet, da Titan- und Zirkoniumverbindungen zum Phosphatieren als Badgifte bekannt sind,
4. 4. in der Praxis nie einen wesentlichen Gehalt an Silanen/Silanolen/Siloxanen/Polysiloxanen enthält,
5. 5. selten einen geringen Gehalt an einem Komplexbildner enthält, denn dieser wird teilweise als Badgift angesehen,
6. 6. üblicherweise in Badlösungen einen Gesamtgehalt an Kationen im Bereich von 3,5 bis 9,5 g/L und an Phosphor-haltigen Verbindungen im Bereich von 5 bis 20 g/L berechnet als PO₄ enthält,
7. 7. oft einen erhöhten Gehalt an Alkali- und Ammoniumverbindungen enthält, wobei der pH-Wert auch bei vergleichsweise hohen Gehalten an Ammoniumverbindungen im Bereich von 2,0 bis 3,5 bleibt,
8. 8. bei einem Gehalt an mindestens einem Komplexfluorid normalerweise nur Verbindungen auf Basis von Bor- oder/und Siliciumkomplexfluorid enthält,
9. 9. beim Phosphatieren von Teilen mit einer Zink- oder/und Mangan-reichen Phosphatierungslösung zumindest bei der Behandlung von Einzelteilen z.B. durch Tauchen oder/und Spritzen üblicherweise kristalline Schichten von oft typischen Kristallformen gebildet werden und
10. 10. beim Blankkorrosionsschutz die kristallinen zinkphosphatierten Oberflächen einen Salzsprühtest an phosphatierten, nicht mit Lack behandelten Oberflächen von typischerweise nur bis zu zwei Stunden ohne Rostbildung aufgrund der Poren und mangelnden Geschlossenheit zeigen, während die erfindungsgemäßen Beschichtungen üblicherweise mindestens zwei Tage ohne zusätzliche Lackbehandlung im Salzsprühtest beständig sind, ohne dass die erfindungsgemäßen Beschichtungen dicker sind als die vergleichbaren phosphatierten Beschichtungen.

Despite the comparatively high phosphate content, the compositions of the present application are not phosphating solutions and the coating process is not phosphating since a phosphating solution:

1. 1. For high-quality phosphate coatings, for example in the case of zinc or / and manganese-rich phosphating processes, a prior activation, for example based on titanium phosphate particles or zinc phosphate particles, is required so that a high-grade phosphate coating can be formed thereon,
2. 2. as a rule can only be used in zinc-containing phosphations in a pH range of 2 to 3.5,
3. 3. usually can not tolerate any content of titanium and / or zirconium compounds of more than 0.05 or more than 0.1 g / l in total without disturbances, since titanium and zirconium compounds are known as bath poisons for phosphating,
4. 4. in practice never contains a substantial content of silanes / silanols / siloxanes / polysiloxanes,
5. 5. rarely contains a low content of a complexing agent, because this is sometimes considered a bad poison,
6. 6. usually contains in bath solutions a total content of cations in the range of 3.5 to 9.5 g / L and of phosphorus-containing compounds in the range of 5 to 20 g / L calculated as PO ₄ ,
7. 7. often contains an increased content of alkali metal and ammonium compounds, the pH remaining in the range from 2.0 to 3.5 even at comparatively high contents of ammonium compounds,
8. 8. if it contains at least one complex fluoride, normally only compounds based on boron or / and silicon complex fluoride,
9. 9. When phosphating parts with a zinc- or / and manganese-rich phosphating solution, at least in the treatment of individual parts, for example by immersion or / and spraying, usually crystalline layers of often typical crystal forms are formed, and
10. 10. For bare corrosion protection, the crystalline zinc phosphated surfaces show a salt spray test on phosphated, non-lacquered surfaces of typically only up to two hours without rusting due to pores and lack of integrity, while coatings according to the invention are usually stable in the salt spray test for at least two days without additional coating treatment, without the coatings according to the invention being thicker than the comparable phosphated coatings.

If very rarely a titanium or / and zirconium compound is used in a phosphating solution in a phosphating process, the contents of these compounds are typically less than 0.2 g / L in total. Because it is known that higher contents of these compounds usually lead to coating defects especially on aluminum-rich surfaces. Very rarely, a complexing agent is added to a phosphating solution. If in very rare cases a silane is used in a phosphating solution in a phosphating process, the contents are very low. But a combination of these additives is never used in phosphating.

WO 96/07772 A1 describes acidic aqueous liquid compositions based on anions of fluoride complexes, di- or tetravalent cations of Co / Mg / Mn / Zn / Ni / Sn / Cu / Zr / Fe / Sr, phosphonate and organic polymer.

EP 1 205 580 A1 relates to chemically treated steel sheets having a zinc-containing layer and a conversion coating of a water-soluble complex manganese compound or a water-insoluble complex titanium compound and at least one organic acid, wherein the conversion coating is dried without rinsing and wherein the composition for the conversion coating manganese, titanium, phosphoric acid or phosphate, fluoride and at least one organic acid and / or its salt and has a pH in the range of 1 to 6.

WO 02/24975 A1 discloses acidic aqueous liquid compositions based on anions of fluoride complexes, di- or tetravalent cations Co / Mg / Mn / Zn / Ni / Sn / Cu / Zr / Fe / Sr, phosphate, phosphonate and organic polymer.

DE 102005015573 A1 discloses a method of coating metallic surfaces with a silane / silanol / siloxane / polysiloxane containing aqueous composition having Ti / Hf / Zr / Al / B containing compound contents and cations and at least one other compound.

WO 2004/053183 A2 refers to aqueous liquid compositions based on complex fluorine-containing acids, water-soluble organic carboxylic acids, phosphate, tannin and polymeric aminophenol compound.

It has been found time and again that the behavior of the aqueous compositions according to the invention and the properties of their coatings are so different compared to phosphating solutions and their phosphate layers that it is not possible to speak of phosphating in the aqueous compositions according to the invention and their coating processes. Nevertheless, the method according to the invention is a conversion coating method of the first type.

It was therefore the object of proposing a coating method with which the corrosion protection layer produced with an aqueous composition without coating with a lacquer / primer has good corrosion protection (= blank corrosion protection), in particular on a metallic strip. Because the coil (reel) is usually to be processed by the steel manufacturer in further processing operation without rust approaches. In addition, good formability or / and also good alkali resistance in mild alkaline cleaning and / or during forming with alkaline emulsions is / are advantageous for some embodiments. Optionally, the coating should also possible after forming have a good corrosion protection and preferably also a good paint adhesion.

• 6 bis 400 g/L mindestens eines Phosphats berechnet als PO₄,
• 3 bis 200 g/L an mindestens einer Titan- oder/und Zirkoniumverbindung,
• 1 bis 200 g/L an mindestens einem Komplexbildner ausgewählt aus der Gruppe von Verbindungen auf Basis von Phosphonsäure, Phytin und Tannin, wobei der Gehalt an Verbindungen auf Basis von Phosphonsäure 0 oder 1 bis 200 g/L beträgt und wobei der Gehalt an Verbindungen auf Basis von Phytin oder/und Tannin 0 oder 0,05 bis 30 g/L beträgt, sowie
• 3,5 bis 100 g/L an Kationen von Aluminium, Chrom(III) oder/und Zink oder/und an mindestens einer Verbindung mit einem Gehalt an Aluminium, Chrom(III) oder/und Zink berechnet als Metall, sowie
• mindestens ein Silan/Silanol/Siloxan/Polysiloxan enthält und
• bei dem ein Nassfilm der wässerigen Zusammensetzung auf metallischen Bändern oder Blechen aufgetrocknet wird, ohne dass der Nassfilm oder der aufgetrocknete Film mit Wasser gespült wird.

The object is achieved with a method for coating and passivating metallic surfaces with an aqueous composition as a solution or as a dispersion, wherein the composition

• 6 to 400 g / L of at least one phosphate calculated as PO ₄ ,
• 3 to 200 g / L of at least one titanium or / and zirconium compound,
• 1 to 200 g / L of at least one complexing agent selected from the group of compounds based on phosphonic acid, phytin and tannin, wherein the content of compounds based on phosphonic 0 or 1 to 200 g / L and wherein the content of compounds on Base of phytin or / and tannin is 0 or 0.05 to 30 g / L, as well as
• 3.5 to 100 g / L of cations of aluminum, chromium (III) or / and zinc or / and of at least one compound containing aluminum, chromium (III) or / and zinc calculated as metal, and
• contains at least one silane / silanol / siloxane / polysiloxane and
• in which a wet film of the aqueous composition is dried on metal strips or sheets without rinsing the wet or dried film with water.

Usually, the aqueous composition according to the invention will be a solution unless particles or / and an emulsion are added, as long as this solution is stable and does not tend to precipitate.

The term "additive" or "adding" in the context of this application means that at least one such substance or mixture is added.

The composition according to the invention and the method according to the invention are used in particular for passivating the metallic surface, but can also be used for pretreatment before a subsequent coating eg with an organic coating and used for other purposes. For the purposes of this patent application, passivation is understood to mean the coating of metallic surfaces in which no subsequent organic coating is normally applied for permanent protection against corrosion. However, in some cases passivation does not preclude the subsequent application of at least one organic coating such as a primer or even a paint system and / or an adhesive.

The aqueous composition according to the invention preferably contains cations of aluminum, chromium (III), iron, manganese or / and zinc or / and at least one compound containing aluminum, chromium (III), iron, manganese or / and zinc. The starting composition according to the invention, that is to say in particular the fresh concentrate and / or the fresh bath composition, but often also the supplementary solution which is added to the bath in use as needed, in particular in order to obtain the bath ready for use, preferably contains a substantial content in many embodiments on cations and / or on at least one compound of aluminum, chromium (III), iron, manganese or / and zinc. In many embodiments, in addition to the cations and / or compounds of aluminum, chromium, iron, manganese, titanium, zinc and / or zirconium, it contains no or no substantial content of other heavy metal cations and / or heavy metal compounds in addition to those just mentioned. Often, it also contains no chromium content. However, in contact with the equipment, with the metallic surfaces to be coated or / and by entrainment of impurities, the composition may often take up further cations and / or compounds. Therefore, the original chromium-free composition may also contain traces or occasionally even low contents, for example, of chromium and / or chromium compounds and / or cations / compounds from other steel refiners. Preferably, the composition contains a total content of cations of aluminum, chromium (III), iron, manganese or / and zinc or / and at least one compound with a content of aluminum, chromium (III), iron, manganese or / and zinc in the range of 3.5 to 100 g / L calculated as metal. The composition preferably contains a total content of cations of aluminum, chromium (III) or / and zinc or / and of at least one compound containing aluminum, chromium (III) or / and zinc in the range from 3.5 to 100 g / L calculated as metal. The contents of aluminum, chromium (III), iron, manganese or / and zinc or of aluminum, chromium (III) or / and zinc in the range from 3.5 to 90, from 3.5 to 80 are very particularly preferred. from 3.5 to 70, from 3.5 to 60, from 3.5 to 50, from 4 to 40, from 4.5 to 35, from 5 to 30, from 5.5 to 25, from 6 to 20 or from 8 to 14 g / L, calculated as metal. Particularly preferred is a content of chromium (III) as cations and / or compounds zero, in about zero or in the range of 0.01 to 30, from 0.1 to 20, from 0.3 to 12, from 0.5 to 8, from 0.8 to 6 or from 1 to 3 g / L calculated as metal. With particular preference the composition according to the invention with respect to the cations and / or the metal-containing compounds consists only of cations of aluminum, chromium (III) or / and zinc or / and of at least one compound containing aluminum, chromium (III) or / and Zinc. The content of chromium (VI) as cations and / or compounds may be in particular zero, about zero or in the range of 0.01 to 8, from 0.05 to 5, from 0.1 to 3 or from 0.3 to 1 Preferably, at least 60%, at least 80%, at least 90% or even at least 95% of these cations and compounds are those based on aluminum and / or zinc. The content of such cations and compounds can be varied widely. If appropriate, these can be complexed. It can also be considered that due to the pickling effect of the main constituent of the metallic surface such as zinc in galvanized surfaces, iron in steel surfaces and aluminum at aluminum surfaces with longer throughput is added at lower levels, because the main component of its own supplements due to the pickling. It is particularly preferred that the composition according to the invention contains essentially only cations of aluminum, titanium, zinc or / and zirconium or only those of the composition be added. It is particularly preferred that only cations and / or compounds of aluminum, chromium (III), titanium, zinc or / and zirconium are added to the composition according to the invention with respect to the cations and / or metal-containing compounds. It is very particularly preferred that the composition according to the invention contains only or essentially only titanium and zinc or titanium and aluminum or are added to the composition. It is particularly preferred that only cations and / or compounds of aluminum, chromium (III), titanium, zinc or / and zirconium are added to the composition according to the invention with respect to the cations and / or metal-containing compounds. Here, if appropriate, further types of cations, in particular trace impurities, introduced impurities or / and impurities thrown out of devices or / and substrates, may occur.

In most embodiments, the content of cations and / or at least one compound of alkaline earth metals is about zero or in the range of 0.001 to 1.5 g / L, from 0.003 to 1 g / L, of 0.01 to 0.5 g / L or from 0.03 to 0.1 g / L, calculated as the respective metal. If the content of these cations / compounds is very low, no disadvantages are to be expected. If the content of these cations / compounds is too high, the stability of the solution is endangered and losses in corrosion protection are to be expected. Alkaline earth metal levels usually interfere with precipitation. Due to the levels of fluoride (including complex fluoride) alkaline earth metal precipitation can easily occur. In most embodiments, the content of cations and / or at least one compound of at least one alkali metal is about zero or in the range of 0.001 to 1.5, from 0.01 to 1, from 0.1 to 0.5, of 0.02 to 0.15 g / L, calculated as the respective metal. However, low alkali metal contents and alkaline earth metal contents often do not interfere when they are on the order of the levels of city water.

The aqueous composition of the present invention preferably has a content of phosphate in the range of 6 to 400 g / L calculated as PO ₄ . More preferably, the phosphate content of the composition ranges from 6 to 350, from 12 to 300, from 18 to 280, from 25 to 260, from 30 to 240, from 40 to 220, from 50 to 200, from 60 to 180, of 70 to 160, from 85 to 140 or from 100 to 120 g / L. If the content of phosphate is too low, the corrosion protection is low. Preferably, a phosphate additive is so high that a significant improvement of the corrosion protection and the surface appearance is obtained. If the phosphate content is too high, dull coatings may form. Preferably, the ratio of Al: PO ₄ in the case of compositions whose content of cations and / or inorganic compounds selected from those based on aluminum, chromium, iron, manganese or / and zinc predominantly comprises those based on aluminum is in the range of 1 : 10 to 1: 25, in particular in the range of 1: 12 to 1: 18. Preferably, the ratio of Zn: PO ₄ in compositions whose content of cations and / or inorganic compounds selected from those based on aluminum, chromium, Iron, manganese and / or zinc or based on aluminum, chromium and / or zinc predominantly those based on zinc, in the range of 1: 4 to 1: 20, in particular in the range of 1: 6 to 1: 15. Preferably, phosphate is selected as at least one compound from monophosphates (= orthophosphates based on PO ₄ ^3- , monohydrogen phosphates based on HPO ₄ ^2- , dihydrogen phosphates based on H ₂ PO ₄ ^- ), diphosphates, triphospha th, phosphorus pentoxide or / and phosphoric acid (= orthophosphoric H ₃ PO ₄ ) was added. A phosphate additive may be a monometal phosphate additive, an additive of phosphoric acid and metal, phosphoric acid and metal salt / metal oxide, diphosphate, triphosphate, polyphosphate or / and phosphorus pentoxide to water or to an aqueous mixture.

In the case of an addition, for example, of at least one orthophosphate, of at least one triphosphate or / and of phosphoric acid, a corresponding chemical equilibrium will be established, in particular in accordance with the pH and the concentrations of these additives. The more acidic the aqueous composition, the sooner the chemical equilibrium shifts to orthophosphoric acid H ₃ PO ₄ , at higher pH values to tertiary phosphates based on PO ₄ ^3- . For the purposes of this application, in principle many different orthophosphates can be added. The orthophosphates of aluminum, chromium and / or zinc have proven to be particularly suitable. Preferably, at least one orthophosphate is added to the aqueous composition with a total addition in the range of 1 to 400 g / L calculated as PO ₄ , more preferably in the range of 5 to 300, from 10 to 250, from 15 to 200, from 20 to 150, from 25 to 100, from 30 to 80 or from 40 to 60 g / L. The total addition corresponds to the total salary.

The aqueous composition can be prepared with phosphoric anhydride P ₂ O ₅ , with a phosphorus-containing acid, with at least one salt or / and esters of orthophosphoric acid and / or with at least one salt or / and esters of a condensed phosphoric acid, optionally together with at least one Metal, carbonate, oxide, hydroxide or / and salt such as nitrate together with phosphoric acid.

The addition of at least one complexing agent may be advantageous and / or necessary if the pH is to be increased, when diluting the composition with water, when receiving levels of ions and / or compounds, in particular of other types of ions and / or other compounds or / and to stabilize the composition, in particular to prevent precipitation and / or dissolve. It serves to leach out of plants an increased content of compounds, in particular of cations such as aluminum, chromium, iron, manganese, zinc or / and of cations that are introduced, and / or from the metallic surfaces are leached to keep dissolved in the composition. Because precipitations such as fluorides, oxides, hydroxides or / and phosphates in particular of aluminum, iron, manganese or / and zinc can interfere because increasingly form sludge. If precipitation occurs, complexing agents can be added as needed to re-dissolve the precipitate. The at least one complexing agent serves in particular to complex cations such as aluminum, chromium, iron, magnesium, manganese, titanium, zinc and / or zirconium and thereby stabilize the solution or suspension, in particular at lower acidity. In addition, in many embodiments, an addition of at least one complexing agent has also proven to be more or less corrosion-protective. Upon re-addition of complexing agent (s) or / and at elevated levels of complexing agent (s) in the aqueous composition, it may be advantageous to also add at least one substantially neutral or basic compound to the composition in order to set a higher pH. The term "complexing agent" in the context of this application also includes chelating agents. In particular, at least one compound based on phosphonic acid and / or on the basis of phytic acid and / or on the basis of tannic acid is used as complexing agent. The higher the content of at least one complexing agent, the higher it is usually possible to adjust the pH of the composition as a function of the amount of cation. The content of complexing agent (s) can be varied within wide ranges. The aqueous composition according to the invention preferably contains a total content of at least one complexing agent in the range from 1 to 200 g / l. The total content of at least one complexing agent is more preferably in the range from 2 to 180, from 3 to 160, from 4 to 130, from 5 to 100, from 6 to 80, from 8 to 70, from 10 to 60, from 12 to 50 , from 15 to 40 or from 20 to 30 g / L. Preferably, the complexing agent content is so high that the composition is a stable solution and that optionally stable solutions are obtained even when diluted with water. If the content of complexing agent is too low, depending on increase the pH of the cation amount or / and increase the contents of cations and / or compounds to precipitations and thus possibly lead to precipitation and, if appropriate, to sludge formation. If the content of complexing agent is too high, the corrosion protection and / or the formability may be impaired.

In the process according to the invention, it is possible to add to the aqueous composition preferably at least one phosphonic acid, at least one salt of a phosphonic acid and / or at least one ester of a phosphonic acid. Preferably, the aqueous composition contains at least one phosphonic acid based compound in the range of from 1 to 200 g / L, more preferably in the range of from 0.3 to 150, from 1 to 80, from 1.5 to 50 or from 2 up to 30 g / L. Particularly preferred is at least one compound based on phosphonic acid, e.g. Diphosphonic acid, diphosphonic acid with an alkyl chain, for example 1-hydroxyethane-1,1-diphosphonic acid (HEDP), aminotris (methylenephosphonic acid) (ATMP), ethylenediaminetetra (methylenephosphonic acid) (EDTMP), diethylenetriaminepenta (methylenephosphonic acid) (DTPMP), diethylenetriamine penta (methylenephosphonic acid) (DTPMP), hexamethylenediamine tetra) methylenephosphonic acid) (HDTMP), hydroxyethylamino-di (methylenephosphonic acid) (HEMPA) or / and phosphonobutane-1,2,4-tricarboxylic acid (PBTC). These substances usually act as complexing agents.

Preferably, the composition according to the invention contains at least one compound based on phytin or / and tannin. These include, inter alia, compounds such as phytic acid, tannic acid and / or their derivatives such as their salts and their esters including their modified compounds and their derivatives. Compounds based on this chemical base can often have a positive influence on corrosion protection in a special way. They also act as complexing agents and are counted for the purposes of this application to the complexing agents. The composition In particular, the compounds based on tannin can vary significantly - for example, depending on the natural raw materials used - and their possibly carried out cleaning and / or chemical modification. They are partly colored. Preferably, the aqueous composition contains at least one compound based on phytin or / and tannin with a total content of these compounds in the range from 0.05 to 30 g / L, particularly preferably in the range from 0.3 to 25 g / L or from 1 to 20 g / L, most preferably in the range of 1.5 to 15 g / L or from 2 to 10 g / L.

In the method according to the invention, the aqueous composition preferably contains a total content of at least one titanium or / and zirconium compound of at least 5 g / L, 10 g / L, 15 g / L, 20 g / L or 25 g / L. In particular, this total content is in the range of 3 to 200 g / L. It is often present in a content in the range of 3 to 100 g / L of Ti or / and Zr calculated as metal. It may optionally be added partially or wholly as at least one complex fluoride and / or partially or wholly present as at least one complex fluoride in the aqueous composition. More preferably, the aqueous composition contains a total content of at least one titanium or / and zirconium compound in the range of from 3 to 160, from 3 to 130, from 4 to 100, from 5 to 80, from 6 to 60, from 8 to 50, of 10 to 40 from 15 to 30 or from 20 to 25 g / L. More preferably, the content of Ti or / and Zr calculated as the metal in the aqueous composition is in the range of from 3 to 90, from 6 to 80, from 10 to 70, from 20 to 60, or from 35 to 50 g / L. As a titanium or / and zirconium compound, at least one compound which is usually stable only in the basic medium, but also with the addition of at least one complexing agent such as a phosphonate and / or at least one protective compound such as a surfactant, may also be added is stable in the acidic medium, said compound then being complexed or / and protected in the aqueous composition. Particularly preferred is as Fluoride-containing compound added only at least one titanium or / and zirconium compound based on complex fluoride. In many embodiments, the composition contains at least one complex fluoride and / or its salt of aluminum, titanium, zinc or / and zirconium, which are present approximately as MeF ₄ or / and MeF ₆ complex. In particular with aluminum-containing metallic surfaces, not too low a complex fluoride addition is important in order to produce an increased pickling effect. More preferably, the aqueous composition contains at least one complex fluoride based titanium and / or zirconium compound in the range of from 1 to 200, from 1.5 to 175, from 2 to 150, from 3 to 120, from 4 to 100, from 5 to 80, from 6 to 60, from 8 to 50, from 10 to 40 from 15 to 30 or from 20 to 25 g / L. Preferably, the addition and content of at least one titanium or / and zirconium compound is so high that a good bare corrosion protection and, if necessary, a good paint adhesion to the subsequent paint / primer coating occurs. If the content of at least one titanium and / or zirconium compound is too high and if complexing agents are present in an insufficient amount, instability of the bath and hence precipitation can easily occur. Because a fluoride or a complex fluoride can also act as a complexing agent. However, fluoride and complex fluoride are not counted as complexing agents for the purposes of this application. The addition and content of a titanium compound has proved to be particularly advantageous for improving the corrosion protection. The addition and content of a zirconium compound has proved to be advantageous in particular in hot-dip galvanized surfaces for improving the paint adhesion. In many embodiments, the titanium or / and zirconium compound according to the invention may be at least one corresponding complex fluoride and / or at least one complexed substance such as at least one titanium chelate, in particular at least one titanium alkoxide, the less reactive titanium and / or zirconium compounds being preferred. Preferably, the weight ratio of silane / silanol / siloxane / polysiloxane to complex fluoride based on titanium or / and zirconium is calculated as added silane or / and Polysiloxane or optionally molar converted to H ₂ TiF ₆ less than 2: 1, less than 1.5: 1, less than 1: 1 or less than 0.5: 1.

In certain embodiments, the composition of the invention contains at least one titanium or / and zirconium-containing fluoride-free compound, such as a chelate. This compound can serve to incorporate titanium or / and zirconium into the composition in a different form and is therefore a possibility of a source of such a compound. Such a compound can significantly improve the corrosion protection and stably keep the aqueous composition in solution. Preferably, the composition of the invention contains a content of titanium and / or zirconium chelates in the range of 0.1 to 200 g / L, more preferably in the range of 1 to 150, 3 to 110, 5 to 90, 7 to 70, 10 to 50 or 15 to 30 g / L. In particular, the content of such compounds is selected such that a content of titanium or / and zirconium in the range from 3 to 60 or 5 to 45 mg / m ² remains on the metallic surface, calculated as metal, determined by X-ray fluorescence. Such a compound is added in particular if no other titanium- or / and zirconium-containing compound is present in the composition according to the invention. Because it is particularly advantageous that at least one titanium or / and zirconium-containing compound is contained in the composition according to the invention. In particular, dihydroxo bis (ammonium lactate) titanate can be used as such a compound.

In the inventive method, the aqueous composition contains preferably approximately no fluoride content or a content of free fluoride F _free in the range of 0.01 to 5 g / l and / or a content of total fluoride F _tot in the range of 3 to 200 g / L. More preferably the composition contains a free fluoride content F _free in the range of 0.1 to 3.5, 0.3 to 2 or from 0.5 to 1 g / l and / or a content of total fluoride F _tot in the range of 3 to 180, from 5 to 140, from 8 to 110, from 10 to 90, from 12 to 75, from 15 to 60 or from 20 to 40 g / L. In many In embodiments, no hydrofluoric acid, no monofluoride or / and no bifluoride is added to the composition according to the invention. In that case, a content of hydrofluoric acid, monofluoride or / and bifluoride in the composition according to the invention can be formed in small amounts from at least one complex fluoride or / and its derivative only on the basis of the equilibrium conditions. In individual embodiments, the inventive composition hydrofluoric acid, monofluoride and / or bifluoride is calculated with a total content of 0.01 to 8 g / L as free fluoride F _free , in particular from 0.1 to 5 or from 0.5 to 3 g / L. added.

In the context of this invention, the term "silane" should also include their hydrolysis, condensation, polymerization and reaction products, ie in particular silanols, siloxanes and optionally polysiloxanes. The term "polysiloxane" is intended to include the condensation, polymerization and reaction products of the polysiloxane.

In the method according to the invention, in many embodiments, the composition preferably contains a content of at least one silane / silanol / siloxane / polysiloxane in the range from 0.1 to 200 g / L, calculated on the basis of silane or polysiloxane of the respective starting compound. It particularly preferably contains a content of at least one compound based on at least one silane / silanol / siloxane / polysiloxane in the range from 0.5 to 180, from 1 to 160, from 2 to 140, from 3 to 120, from 4 to 100 , from 5 to 90, from 6 to 80, from 8 to 70, from 10 to 60, from 12 to 50, from 15 to 40 or from 20 to 30 g / L, calculated respectively based on silane or polysiloxane of the respective starting compound. If the content of silane / silanol / siloxane / polysiloxane is too low, the corrosion protection of the coating deteriorates, especially in hot-dip galvanized surfaces. If the content of silane / silanol / siloxane / polysiloxane is too high, it can lead to instability of the solution and thus to precipitations or / and to incomplete wetting of the metallic surface. An addition of and content of at least one surfactant (wetting agent) can cause problems prevent at high levels, but also affect the corrosion protection of the coating produced. It has been found that a content of at least one surfactant can in some cases have a very strong influence on the properties of the coating according to the invention, in particular in corrosion protection. The corrosion protection can be significantly improved in particular with less high quality grades of HDG. For this purpose, preferably at least one nonionic surfactant is added, optionally alternatively or additionally, at least one cationic surfactant. A second surfactant may optionally act as a solubilizer. especially added as silane / silanol / siloxane or / and as polysiloxane, the corrosion protection often improves significantly. In particular, in most embodiments at least one silane is added while at least one polysiloxane is added only in individual embodiments either alone or in addition to at least one silane.

The composition preferably contains in each case at least one silane / silanol / siloxane / polysiloxane based on alkoxysilane, alkylsilane, amidosilane, aminosilane, bis-silyl-silane, epoxysilane, fluorosilane, imidosilane, iminosilane, isocyanatosilane, (meth) acrylatosilane and / or vinylsilane. Among these silanes / silanols / siloxanes / polysiloxanes, aminosilanes-based silanes / silanols / polysiloxanes have been found to be particularly useful, although the other silanes / silanols / siloxanes referred to herein may also be important depending on the embodiment. When adding silanes or / and derivatives thereof, which are optionally present after further condensation, in particular at slightly elevated pH, for example based on silanes / silanols / siloxanes having at least one nitrogen-containing group, eg of at least one amino group (= aminosilanes) , Amido group, imino group or / and imido group or / and taking up protons having at least one ammonium group, these silanes / silanols / siloxanes contribute to an increase in the pH. Also, this may raise the pH, for example, from the original values in the range of 0.5 to 2 to values in the range of 1.5 to 4. Especially Preferred is a content of silanes / silanols / siloxanes having at least one nitrogen-containing group such as, in each case, at least one amino group (= aminosilanes), amido group, imino group or / and imido group. The alkylsilanes may in particular be di-, tri- and / or tetrafunctional. The alkyl silanes may in particular be without an organically functional side chain or, in particular, may have a terminal nitrogen-containing group. The alkylsilanes may optionally be without side chain, but may also have at least one side chain with a chain length of up to ten carbon atoms. Preferably, in some embodiments, the aqueous composition comprises each an addition of and content of at least one compound based on at least one silane / silanol / siloxane / polysiloxane a) having at least one nitrogen-containing group such as at least one amino group or ammonium group, b) based on of bis-silane (s), c) based on epoxysilane (s), d) based on fluorosilane (s), e) based on isocyanatosilane (s), f) based on (meth) acrylatosilane (s) , g) based on vinylsilane (s), h) based on alkoxysilanes and / or i) based on alkylsilane, in each case in the range from 0.5 to 160 g / l, particularly preferably in the range from 1 to 120, of 2 to 80, from 3 to 50, from 5 to 35 or from 8 to 20 g / L. Particularly preferred silanes are 3-aminopropyltriethoxysilane and / or 3-aminopropyltrimethoxysilane (APS), N- [2- (aminoethyl)] - 3-aminopropyltrimethoxysilane (AEAPS), methylsilane, butylsilane, epoxysilane or / and tetraethoxysilane (TEOS). For some silanes / silanols / siloxanes / polysiloxanes, HF gas may form at higher fluoride levels.

Depending on the type and degree of polymerization, such as condensation, it is also possible to form siloxanes and / or polysiloxanes. Alternatively, it has been found that the addition of and content of at least one polysiloxane or the addition of a combination based on silane and polysiloxane can also be advantageous.

In the method according to the invention, the composition preferably contains at least one organic monomer / oligomer / polymer / copolymer. The term copolymer in the sense of this application also includes block copolymers and / or graft copolymers. The addition of and content of at least one such organic compound, preferably at least in part based on (meth) acrylic, epoxy, ethylene, polyester or / and urethane, is important in some embodiments to provide corrosion protection, paint adhesion, formability, etc. To improve friction and / or the absorption of oil-containing contaminants from the oiled and / or soiled metallic surface. The latter is often used to avoid the cleaning of oiled and / or soiled metallic surfaces. Hereby, optionally, a small amount of tempering agent from a temper rolling, a small amount of rust protection oil of a lubrication for reasons of temporary rust protection or / and a small amount of forming oil from a forming process on a metallic surface coated according to the invention can be included. Preferably, the aqueous composition contains at least one organic monomer / oligomer / polymer / copolymer content in the range of from 0.1 to 180 g / L, more preferably in the range of from 2 to 120, from 5 to 80, from 8 to 55, or from 12 to 30 g / L. Preferably, the content of organic monomer / oligomer / polymer / copolymer is so high that the formability is improved, in particular, the friction during forming is reduced. Preferably, the content of organic monomer / oligomer / polymer / copolymer is so low that the stability of the aqueous composition is maintained and a good surface appearance of the coating is ensured, so that in particular no dull or / and streaky coatings arise.

Preferably, the composition contains at least one organic monomer / oligomer / polymer / copolymer based on or / and containing (meth) acrylic, epoxy, ethylene, polyester or / and urethane. The at least one ingredient mentioned herein may also be at least one ingredient of copolymer (s). The aqueous composition preferably comprises a content of at least one organic monomer / oligomer / polymer / copolymer based on a) (meth) acryl, b) epoxide, c) ethylene, d) polyester or / and e) urethane in each case in the range from 0 , 5 to 80 g / L, more preferably in the range of 2 to 60, from 5 to 50, from 8 to 40 or from 15 to 30 g / L.

In the method according to the invention, the composition preferably contains in each case at least one inorganic or / and organic compound in particle form. In particular , organic particles may be present as a component of organic polymer / copolymer. Preferably, in some embodiments, the aqueous composition contains a content of inorganic and / or organic particles in the range of 0.05 to 80 g / L, more preferably in the range of 0.3 to 50, from 1 to 30, from 1.5 to 15 or from 2 to 10 g / L.

The composition according to the invention preferably contains at least one inorganic compound in particle form based on Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZnO, ZrO ₂ or / and corrosion protection particles which have a mean particle diameter of less than 300 nm measured under a scanning electron microscope. The inorganic particles such as those based on Al ₂ O ₃ , SiO ₂ , TiO ₂ or / and ZrO ₂ often act as particles with barrier effect and optionally with connection to the metallic surface. In this case, ZnO particles, for example, can have a corrosion-protecting effect up to their possibly occurring dissolution. The corrosion protection particles may in particular be those based on, for example, silicate, especially alkali silicate and / or alkaline earth silicate, but also based on phosphates, phosphosilicates, molybdates, etc. Corrosion protection particles can help to protect against corrosion, in particular due to their barrier function and / or the release of ions. Preferably, the content of inorganic particles is so low that no disturbing friction during forming occurs. Preferably, the content of inorganic particles is so high that the particles have a barrier function and increased corrosion protection is achieved.

In certain embodiments, the composition according to the invention contains at least one accelerator, e.g. at least one accelerator selected from the group consisting of accelerators based on chlorate, nitrite, nitrobenzenesulfonate, nitroguanidine, perborate and at least one other nitroorganic compound with oxidizing properties which are known from phosphating. These compounds can also help to reduce or eliminate the formation of hydrogen gas at the interface with the metallic surface. In some embodiments, the aqueous composition contains at least one of these accelerators in the range of 0.05 to 30 g / L, more preferably in the range of 0.3 to 20, from 1 to 12, from 1.5 to 8 or from 2 to 5 g / L.

Preferably, the composition according to the invention contains at least one additive, e.g. in each case at least one wetting agent, a demulsifier, an emulsifier, a defoamer, a corrosion inhibitor and / or a wax. If necessary, at least one additive can be added, as is customary and basically known in the case of conversion coatings, passivations or lacquers / primers. Preferably, the aqueous composition contains at least one additive having a total content of the additives in the range from 0.001 to 50 g / L, more preferably in the range from 0.01 to 30, from 0.1 to 10, from 0.5 to 6 or from 1 up to 3 g / L.

The object is further achieved with a coating produced by the method according to the invention on a metallic surface.

• 1 bis 100 g/L Al, Cr(III) oder/und Zn zusammen,
• 6 bis 400 g/L Phosphat als PO₄,
• 1 bis 200 g/L Komplexbildner auf Basis von Phosphonsäure, Phytin und Tannin, jedoch nur 0 oder 1 bis 30 g/L auf Basis von Phytin oder/und Tannin,
• 3 bis 100 g/L Ti oder/und Zr zusammen berechnet als Metall,
• 0,1 bis 200 oder in etwa Null g/L F aus mindestens einer Fluor-Verbindung (F_gasamt) und
• 0,1 bis 200 g/L Silicium-Verbindung(en)

sowie gegebenenfalls noch mindestens eine der weiteren in dieser Anmeldung genannten Verbindungen.Preferably, the composition according to the invention contains:

• 1 to 100 g / L Al, Cr (III) or / and Zn together,
• 6 to 400 g / L phosphate as PO ₄ ,
• 1 to 200 g / L complexing agent based on phosphonic acid, phytin and tannin, but only 0 or 1 to 30 g / L based on phytin or / and tannin,
• 3 to 100 g / L Ti or / and Zr calculated together as metal,
• 0.1 to 200 or about zero g / LF from at least one fluorine compound (F _gasamt ) and
• 0.1 to 200 g / L silicon compound (s)

and optionally at least one of the other compounds mentioned in this application.

• 8 bis 75 g/L Al, Cr(III) oder/und Zn zusammen,
• 40 bis 280 g/L Phosphat als PO₄,
• 20 bis 120 g/L Komplexbildner, auf Basis von Phosphonsäure, Phytin und Tannin, jedoch nur 0 oder 1 bis 30 g/L auf Basis von Phytin oder/und Tannin,
• 3 bis 60 g/L Ti oder/und Zr zusammen berechnet als Metall,
• 5 bis 120 oder in etwa Null g/L F aus mindestens einer Fluor-Verbindung (F_gesamt) und
• 10 bis 160 g/L Silicium-Verbindung(en)

sowie gegebenenfalls noch mindestens eine der weiteren in dieser Anmeldung genannten Verbindungen.Most preferably, the aqueous composition contains:

• 8 to 75 g / L Al, Cr (III) or / and Zn together,
• 40 to 280 g / L phosphate as PO ₄ ,
• 20 to 120 g / L complexing agent, based on phosphonic acid, phytin and tannin, but only 0 or 1 to 30 g / L based on phytin or / and tannin,
• 3 to 60 g / L Ti or / and Zr calculated together as metal,
• From 5 to 120 or about zero g / LF of at least one fluorine compound (F _total ) and
• 10 to 160 g / L silicon compound (s)

and optionally at least one of the other compounds mentioned in this application.

These figures apply to both concentrates and baths. In the case of baths, all of the above information on the areas can be divided by the dilution factor 4, for example.

Preferably, the weight ratio of (Al, Cr ³⁺ , Fe, Mn and Zn) is: (Ti and Zr) or / and of (Al, Cr ³⁺ and Zn): (Ti and Zr) in the range of 0.1: 1 to 3: 1. These weight ratios are particularly preferably in the range from 0.5: 1 to 2.5: 1 or from 1: 1 to 2: 1.

In addition to the added levels, in particular of aluminum, chromium (III), iron, manganese, titanium, zinc or / and zirconium, these and optionally Other cations may also be present in the composition according to the invention: on the one hand by entrainment, for example, from previous baths, by impurities or / and by dissolving out, for example, from tank and pipe materials and from the surfaces to be coated, on the other hand by adding further cations / compounds with a metal content such as at least one alkali metal, molybdenum or / and vanadium.

Preferably, in many embodiments, the aqueous composition of the present invention is free or substantially free of compounds based on carboxylic acid, acrylic acid, phenol, starch, chromium (VI) or / and based on other heavy metals, e.g. those based on chromium, molybdenum, nickel, vanadium or / and tungsten. In many embodiments, the aqueous composition according to the invention is preferably free or substantially free of compounds which are used as accelerators in the phosphating, in particular of compounds based on chlorate, nitrite, nitroguanidine, peroxide or / and other N-containing accelerators.

The compositions of the invention are preferably free or substantially free of chromium (VI). However, they may also be free or substantially free of chromium (III), in some cases optionally free or substantially free of cations and / or compounds of chromium, in some of the compositions according to the invention.

Preferably, the aqueous composition contains no or only a content of calcium and / or magnesium of not more than 0.5 g / L, more preferably not more than 0.15 g / L, or / and of at least one toxic or environmentally unfriendly Heavy metal such as chromium of not more than 0.5 g / L, more preferably not more than 0.15 g / L. Fluoride-free compositions may also contain some or more calcium or / and magnesium.

The composition according to the invention preferably has a pH in the range from 0 to 10. In particular, the pH is in the range from 0.3 to 8, from 0.5 to 6, from 0.8 to 5, from 1 to 4 or from 2 to 3. Concentrates often have a pH value in the range of 0 , 3 to 3, baths often from 1.5 to 4. The pH is often at the beginning of the work, at high concentrations or / and in non-truncated systems at values of 0.1 to 2, often in the range of 0 , 3 to 1. By dilution with water or / and by addition of certain basic substances such as ammonia, at least one amine compound (monoamines, diamines, triamines, tetramines, pentamines and others) or / and at least one polyamine compound (polymeric amine compound), at least one less acidic or substantially neutral silicon-containing compound or / and at least one organic polymer / copolymer, the pH in a range from 1 to 10, in particular from 1.5 to 7, from 1.8 to 5 or from 2 to 3.5 are raised, which is often advantageous. As a result, the composition itself is less corrosive. The at least one amine compound or / and at least one polyamine compound is in many cases also suitable as a pickling inhibitor. In principle, with an increased content of at least one complexing agent, a pH of the composition in the range from 2 to about 10 can be set, in which case an increased amount of at least one approximately neutral or / and basic compound is added. For influencing the pH, in particular ammonia, at least one other basic and optionally nitrogen-containing compound, at least one basic carbonate, hydroxide or / and oxide-containing compound, at least one organic polymer / copolymer or / and at least one silane / silanol / Siloxane / polysiloxane are added. For example, zinc oxide, manganese carbonate or / and substantially neutral or basic polymers or / and copolymers may also be added. The content of approximately neutral or / and basic agents which help to adjust the pH and are added predominantly or only for the purpose of pH adjustment may preferably be zero or in the range from 0.05 to 100 g / L, more preferably in the range of 0.2 to 60, from 1 to 40, from 2 to 25, from 3 to 18 or from 4 to 12 g / L. Due to levels of fluoride or / and silane / polysiloxane, it may be advantageous not to measure with a glass electrode but to use pH indicator paper.

In the method according to the invention, the aqueous composition preferably has values of the free acid FS (FA) in the range of 2 to 25 points, values of the total acid GS (TA) in the range of 20 to 45 points or / and values of the total acid Fischer GSF (TAF) in the range of 12 to 20 points. The acid value S for the ratio of FS: GS (FA: TA) is preferably in the range of 0.1 to 0.6. The acid value S for the ratio of FS: GSF (FA: TAF) is preferably in the range of 0.2 to 1.3. Particularly preferably, the values of the free acid FS (FA) are in the range of 6 to 16 points, values of the total acid GS (TA) in the range of 27 to 37 points or / and values of the total acid Fischer GSF (TAF) in the range of 15 to 18 points. More preferably, the acid value S for the ratio of FS: GS (FA: TA) is in the range of 0.2 to 0.5 or / and the acid value S for the ratio of FS: GSF (FA: TAF) is in the range of 0 , 35 to 1.0. These values apply to titrations at concentrations of 60 g / L of solids and active substances, with the exception of ammonia levels.

An amount of 60 g of the aqueous composition to be analyzed is first made up to 1 liter with water and then diluted. To determine the free acid, 10 ml of the composition after dilution to 100 ml with deionized water (deionised water) using a Titroprocessor and an electrode with 0.1 M NaOH titrated to the inflection point. The consumed amount of 0.1 M NaOH per 10 ml of the diluted composition gives the value of the free acid (FS) in points.

The total content of phosphate ions is determined by titrating the titration solution to the 2nd inflection point after addition of potassium oxalate solution using a Titroprocessor and an electrode with 0.1 M NaOH following determination of the free acid. The consumption of 0.1 M NaOH for 10 ml of the diluted composition corresponds to Fischer's total acid (GSF). If this value is multiplied by 0.71, the total content of phosphate ions is calculated as P ₂ O ₅ ( See W. Rausch: "The phosphating of metals". Eugen G. Leuze-Verlag 1988, pp. 300 ff ).

The so-called S value for the ratio FS: GS or FS: GSF is obtained by dividing the value of the free acid by the value of the total acid or total acid according to Fischer.

The total acid (GS) is the sum of the divalent cations present as well as free and bound phosphoric acids (the latter being phosphates). It is determined by the consumption of 0.1 molar sodium hydroxide solution using a Titroprozessors and an electrode. This consumption per 10 ml of the diluted composition corresponds to the total acid score.

Table 2 gives an overview of measurement results. These are formulations with the same starting composition, in which only the pH was varied with different amounts of ammonia.

Preferably, all or most of the compounds which are also contained in the solution in appropriate components are added as additives to the aqueous concentrate for the preparation of an aqueous composition. The composition of the bath is preferably prepared by diluting the aqueous concentrate with 10 to 1000% of the solid and active ingredient content of the concentrate with water from the aqueous concentrate. But also a highly concentrated and / or undiluted Solution or dispersion can be used advantageously in some embodiments.

All metallic materials can be coated with their metallic surfaces . Preferably, metallic surfaces of aluminum, iron, copper, magnesium, titanium, zinc, tin and / or their alloys are coated, in particular zinc, steel, hot dip galvanized (HDG), electrolytically galvanized, Galvalume®, Galfan® - or / and Alusi® surfaces. The composition according to the invention has proved to be outstanding, especially with zinc-rich or / and aluminum-rich metallic surfaces. For surfaces of iron and steel materials, in particular compositions having a pH in the range of 4 to 10, in particular of at least 5 or even of at least 7 have been recommended in order to avoid rapid rusting (flash rusting). The metallic components coated by the process according to the invention can be used in particular in vehicle construction, as architectural elements in construction or for the manufacture of devices and machines, such as, for example, domestic appliances.

The coating produced according to the invention may have a widely varying coating composition. In particular, it may be characterized in that it contains: Al, Cr or / and Zn are calculated as metal 1 to 100 mg / m ² , Ti or / and Zr calculated together as metal 1 to 100 mg / m ² , Si compound (s) calculated as metal 0.1 to 25 mg / m ² or / and P ₂ O ₅ 3 to 400 mg / m ² .

The coating according to the invention particularly preferably contains: Al, Cr or / and Zn are calculated as metal 10 to 70 mg / m ² , Ti or / and Zr calculated together as metal 10 to 70 mg / m ² , Si compound (s) calculated as metal 1 to 15 mg / m ² or / and P ₂ O ₅ 80 to 220 mg / m ² .

These levels can be determined by X-ray fluorescence analysis on a trimmed coated sheet. Here, the weight ratio of (Al, Cr ³⁺ and Zn): (Ti and Zr) of the coating composition may preferably be in the range of 0.5: 1 to 1.8: 1, more preferably in the range of 0.9: 1 to 1.4: 1.

The layer weight of the layer formed according to the invention can vary within wide limits. It may range from 0.01 to 12, from 0.05 to 10, from 0.1 to 8, from 0.3 to 6, from 0.5 to 4 or from 0.8 to 2 g / m ² , In the case of coating in strip systems, it can be in the range from 10 to 1000 mg / m ² , preferably in the range from 30 to 800 or from 60 to 650 mg / m ² , more preferably in the range from 100 to 500 or from 130 to 400 mg / m ² , very particularly preferably in the range from 160 to 300 or from 200 to 250 mg / m ² . The total content of titanium or / and zirconium in the dry film is preferably in the range of 1 to 100 mg / m ² of Ti or / and Zr calculated as metal, particularly preferably in the range of 10 to 60 mg / m ² . The total content of titanium or / and zirconium can be measured, for example, by X-ray fluorescence. The total content of silicon in the dry film when coated in strip lines is preferably in the range from 1 to 80 mg / m ² of Si calculated as metal, more preferably in the range of 3 to 40 mg / m ² . The total content of P ₂ O ₅ in the dry film is preferably in the range of 30 to 400 mg / m ² of P ₂ O ₅ , particularly preferably in the range of 60 to 300 mg / m ^2, when coated in strip lines.

The thickness of the coatings according to the invention is often in the range from 0.01 to 5.0 μm, in particular in the range from 0.5 to 3.5, from 0.8 to 2.5 or from 1.0 to 2, when coating in strip systems , 0 μm. For coating in strip systems, the thickness of the coating is often in the range from 0.01 to 1.2 μm, in particular in the range from 0.1 to 1.0, from 0.2 to 0.8 or from 0.3 to 0, 6 μm.

The aqueous compositions of the invention often have a concentration of solids and active ingredients (total concentration) in the range of 10 to 800 g / L. A concentrate may often have a total concentration in the range of 200 to 800 g / L, especially from 400 to 750 g / L. It can be diluted with water if necessary. The dilution of a concentrate is preferably carried out by a factor in the range of 1.1 to 25, more preferably in the range of 1.5 to 16, from 2 to 10 or from 3 to 6. The content of solids and active ingredients in the aqueous The composition depends above all on the type of substrate to be coated, on the particular installation and on the wet film thickness caused by the installation.

In many embodiments, the composition of the invention is used on metallic strip in coil coating processes. Many of the belt systems have a belt speed in the range of 10 to 200 m / min. The faster the belt is driven, the faster the reactions between the composition according to the invention and the metallic surface must take place so as not to require too long plant sections. The reaction time between application of the composition and its complete drying can take from a fraction of a second up to about 60 seconds. This may, in particular in the case of the faster belt systems, mean that the aqueous composition is too less reactive and therefore has to have a stronger acidity and a stronger pickling power. Preferably, its pH is in the range of 0.5 to 3.5 in coil coating processes. The concentration of all solids and active ingredients of the aqueous composition for coating in belt plants is often in the range of 200 to 800 or from 300 to 650 g / L. The contents of individual components or additives are adjusted according to the total contents. Usually, the aqueous composition is applied to the clean or cleaned metallic strip by wet-spraying and squeezing, which often has a wet film thickness in the range from 1 to 4 microns. Occasionally, a Chemcoater or Rollcoater can be used instead.

In most cases, the wet film is dried on metallic strips or sheets ( dry or no-rinse method ). The drying may preferably be carried out in a temperature range from about room temperature to about 75 ° C peak metal temperature (PMT). The composition according to the invention can be aligned, for example, by means of suitable concentration and suitable pH, especially for a slow or rapid treatment in a belt system. Thus, neither the wet film, nor the dried film is rinsed with water, so that the ausgebeizten from the metallic surface cations and compounds are not removed, but are incorporated into the coating.

In the coating of metal parts according to the invention, such as sheet metal sections , castings, shaped articles and complicated shaped parts, the reaction time between the first contacting of the composition until its complete drying (no-rinse process) or until rinsing off the components which can be removed by rinsing with water (rinse method) preferably take 0.5 to 10 minutes. Longer times are possible in principle. The concentration of all solids and active ingredients of the aqueous composition is often in the range of 10 to 300 or 30 to 200 g / L. In particular, in the case of rinsed coatings, it may sometimes be advisable to treat the coatings with a rinse-off solution, since a lot is often removed when rinsing with water. Instead of a layer formation, in some compositions it may also happen that substantially only a staining effect and / or only a very thin coating occurs in contact with the composition according to the invention, so that, for example, the zinc crystallization pattern becomes recognizable in hot-galvanized surfaces on zinc grain boundaries , This also illustrates the difference to a phosphating.

It was surprising that the coating according to the invention, in contrast to a phosphate layer, offers an unusually strong blank corrosion protection, even if the coating according to the invention is often much thinner than a phosphate layer and even if it is chromium-free. The blank corrosion protection of the coatings according to the invention is often better at least by the time factor 20 or 30 than with comparable zinc-phosphated coatings.

It was surprising that an increased content of ammonia in the composition according to the invention did not deteriorate the corrosion protection and is greatly improved by a content of silane, in particular on hot-dip galvanized surfaces.

It was surprising that the composition of the invention is an unusually stable solution at an increased content of complexing agent even at very high levels of solids and active ingredients.

Examples and Comparative Examples:

Examples (B) and comparative examples (VB) described below are intended to explain the subject matter of the invention in more detail.

Comparative Example VB 0:

Aqueous solutions were used to coat hot dip galvanized sheets in the laboratory roll coater containing only an addition of zinc dihydrogen phosphate (60%) in the range of 40 to 100 g / L and a corresponding molar amount of orthophosphoric acid in deionized water. There were coatings with a coating weight of about 110 to 360 mg / m ² P ₂ O ₅ . The coatings showed in the neutral salt spray test (NSS test) according to DIN EN ISO 9227 (blank corrosion test) already after about 1 hour corrosion phenomena of 1 to 5 area% and already after 8 hours full-surface, thick, white layers of zinc corrosion products. The condensate constant climate test according to DIN EN ISO 6270-2 (KK test) revealed white rust of up to 10 area% after 2 days. Such coatings are not usable in European industry for any use.

Comparative Example VB 0a:

In comparison, an aqueous solution with an addition of zinc dihydrogen phosphate (60%) in the range of 40 to 60 g / L, with an addition of a corresponding molar amount of orthophosphoric acid, to 25 g / LH ₂ TiF ₆ (50% ), to 6 g / L γ-APS (γ-aminopropyltriethoxysilane) and with deionized water as the remainder for coating hot dip galvanized sheets in the laboratory. There were coatings of about 110 to 165 mg / m ² P ₂ O ₅ , 36 mg / m ^{2 of} Ti and 6 mg / m ^{2 of} Si. These coatings showed in the neutral salt spray test (NSS test) according to DIN EN ISO 9227 (blank corrosion test) only after 48 to 72 hours on the entire surface related corrosion attack of 1 to 5 area%, although no chromium was included in the coating , For high demands in the European industry resistances in the NSS test over 2 days, rarely over 3 or 4 days, with corrosion phenomena ≤ 5 area% are demanded today. Such blank corrosion resistance is usually achieved only with chromium-rich systems. With the process of the present invention, blank corrosion resistances of 2 to 5 days were achieved, with the substrates and compositions being varied. In the condensate constant climate test according to DIN EN ISO 6270-2 (KK test), however, the improvement compared to the comparative example VB 0 is significantly lower than with the neutral salt spray test (NSS test). Even after 10 days of KK testing, no rust had formed.

Inventive Examples B2 - B6, B9 - B25, B27 - B29, B33, B34, B36, B38 - B40 and B45 - B48 and Comparative Examples VB 1a, VB 7a, VB 8, VB 26, VB 30 - VB 32, VB 35, VB 37, VB 41 - VB 44, VB 49 and VB 1 -VB 7:

Aqueous compositions were mixed whose compositions are shown in Tables 1 as concentrates. The dilution factor illustrates the dilution to the bath concentration used, that is from a concentrate to a bath, so that for example a concentrate used 200g and diluted with water to 1000g using dilution factor 5. Aluminum was used as monoaluminum phosphate, chromium as Complexed chromium (III) fluoride or / and chromium (III) phosphonate, iron as iron (III) nitrate hydrate, manganese as manganese carbonate and / or manganese oxide, zinc added as Monozinkphosphat and / or zinc oxide. As silanes there were added as No. 1) 3-aminopropyltriethoxysilane (APS), as No. 2) N- (2-aminoethyl) -3-aminopropyltrimethoxysilane (AEAPS) and as No. 3) tetraethoxysilane (TEOS). The complexing agents used as No. 1) were 1-hydroxyethane-1,1-diphosphonic acid (HEDP) and as No. 2) phytic acid. The inhibitors which were added as No. 1) polymeric quaternary ammonium salt, as No. 2) quaternary ammonium salt, as No. 3) polyvinylpyrrolidone and as No. 4) tetraethanolamine. Hexafluorotitanic acid, hexafluorozirconic acid or dihydroxo-bis (ammonium lactate) titanate were added as the titanium or zirconium compound. The wax used was a wax emulsion based on oxidized polyethylene. In order to further lower the coefficient of friction of the coating according to the invention, it is also possible to add at least one glycol, in particular at least one polyethylene glycol. The adjustment of the pH was optionally carried out by means of aqueous ammonia solution. The range of pH values apply simultaneously to concentrates and bath concentrations. When diluting the concentrates to make bath solutions, care was taken to avoid precipitation. Concentrates and bath solutions were stored at room temperature for one to 24 hours before use.

Then, in each case at least 9 plates made of hot-dip galvanized steel (HDG) in Examples B 2 to B 6, B 9 to B 25 and B 36, B 38 to B 40 and in Comparative Examples VB 1 to VB 4 and VB 1a, VB 7a , VB 8, VB 26, VB 35, VB 37, VB 41, VB 42, VB 43 and VB 44, sheets of Galvalume® (AZ) in Examples B 27 to B 29 and Comparative Examples B 30 to B 32, sheets made Galfan® (ZA) used in Example B 33 or sheets of Alusi® (AS) in Example B 34 and Comparative Example VB 35. Most of the samples used high quality HDG (HDG / 3) sheets, which are referred to in the tables as HDG, while also using a lower quality coil ("HDG / 4").

The sheets were pre-cleaned with a cloth to largely remove adherent corrosion protection oil and to achieve an even distribution of the oil or other contaminants. Subsequently, the panels were spray-cleaned with a mildly alkaline, silicate-free powder cleaner until complete wettability with water was present. The duration for this was generally 20 to 30 s. This was followed by rinsing with city water in the dipping, rinsing with city water for 6 s by spraying and rinsing with demineralised water for 6 s. The majority of the adhered water was then removed from the sheets by squeezing between two rubber rolls. Subsequently, the sheets were blown dry with oil-free compressed air.

The dry panels were contacted with the aqueous composition of about 25 ° C using a laboratory roll coater. The pH of the compositions was determined with pH indicator paper. A wet film of about 9 to 10 μm thickness was applied. By drying this wet film, a dry film of 0.2 to 0.6 μm in thickness was produced. For this purpose, the sheets treated in this way were dried at about 40 or 65 ° C. PMT. Subsequently, the edges of the coated sheets were taped with commercially available adhesive tape to eliminate edge effects during the corrosion test.

The coated sheets were then tested for their bare corrosion protection in the condensed water constant climatic test (KK test) according to DIN EN ISO 6270-2 and in the neutral salt spray test (NSS test) in accordance with DIN EN ISO 9227. The evaluation was done visually. The values given for corrosion correspond to the percentage of area that corresponds to the total area (100%) accessible to the chemical load. For Galvalume® sheets, "black rust" and "white rust" were evaluated in total. The results of the corrosion tests illustrate the range of corrosion protection, using all measurement results including the measured values, which are to be regarded as outliers.

In Comparative Examples VB 5 to VB 7 electrolytically galvanized sheets (ZE) were contacted with typical zinc-containing phosphating solutions after prior mild alkaline cleaning, rinsing with tap water and activation with titanium phosphate. The phosphating was carried out in Comparative Examples VB 5 and VB 6 at temperatures ranging from room temperature to 40 ° C by spraying and rinsing (rinse method), in the Comparative Example CE 7 at 55 to 60 ° C by rolling and drying (no-rinse -Method). The former were also oiled or rinsed.

Table 1: Overview of the compositions of the solutions used and their composition and the properties of coatings produced therewith and of corresponding compositions for comparison Content in g / L VB 1a B 2 B 3 B 4 B 5 VB 6 VB 7 VB 8 B 9 B 10 substratum HDG HDG HDG HDG HDG HDG HDG HDG HDG HDG Zn 6.4 12.8 12.8 19.1 19.1 19.1 12.8 12.8 57.1 57.1 al 7.4 4.9 4.9 2.4 2.4 2.4 - - - - PO ₄ 105.8 107.5 107.5 109.3 109.3 109.3 55.4 55.4 248.8 248.8 P ₂ O ₅ 79.1 80.4 80.4 81.7 81.7 81.7 41.4 41.4 185.9 185.9 H ₂ TiF ₆ 72.5 72.5 72.5 72.5 72.5 72.5 72.5 72.5 162.5 162.5 Ti 21.2 21.2 21.2 21.2 21.2 21.2 21.2 21.2 47.5 47.5 F _total 50.4 50.4 50.4 50.4 50.4 50.4 50.4 50.4 113.0 113.0 Complexing agent No., g / L 1) 69.6 1) 34,8 1) 69.6 1) 69.6 1) 34,8 1) 21,9 1) 34,8 1) 34,8 1) 78.0 1) 78.0 Silane no., G / L 1) 34,8 1) 34,8 1) 34,8 1) 34,8 1) 34,8 1) 34,8 1) 34,8 1) 34,8 1) 78.0 1) 156.0 NH ₃ - - - - - - - 17.4 45.6 35.1 dilution factor 5 5 5 5 5 5 5 5 10 10 PH value 0.5-1 0.5-1 0.5-1 0.5-1 0.5-1 0.5-1 0.5-1 2.2-2.5 1.9-2.2 1.9-2.2 Coating weight mg / m ² : Si 6 6 6 6 6 6 6 6 6 12 Ti 37 39 36 37 36 36 37 34 34 33 P ₂ O ₅ 225 190 220 220 175 155 96 100 170 165 KK test 10 days 0% 0% 0% 0% 0% 0% nb nb nb nb KK test 20 days nb nb nb nb nb nb 70-90% 5-15% 0% 0% Salt spray test 3 days <5-10% <5-15% <1-10% <1-5% <1-10% <1-1% nb nb nb <5-15% Salt spray test 4 days 5-10% <5-20% <5-10% 1-10% <1-15% <1- <5% 10-20% <5-80% <5-20% nb Content in g / L B 11 B 22 B 13 B 14 B 15 B 16 B 17 B 18 B 19 B 20 substratum HDG HDG HDG HDG HDG HDG HDG HDG HDG HDG Zn 57.1 25.5 38.2 25.5 25.5 25.5 25.5 25.5 25.5 25.5 Mn - - - 5.6 4.2 - - - - - PO ₄ 248.8 111.0 166.5 111.0 111.0 111.0 111.0 111.0 111.0 111.0 P ₂ O ₅ 185.9 82.9 124.4 82.9 82.9 82.9 82.9 82.9 82.9 82.9 H ₂ TiF ₆ 130 72.5 72.5 58.0 72.5 - 72.5 72.5 72.5 72.5 H ₂ ZrF ₆ - - - - - 40.6 - - - - Ti or Zr 38.0 21.2 21.2 16.9 21.2 18.3 21.2 21.2 21.2 21.2 F _total 90.4 50.4 50.4 40.4 50.4 22.3 50.4 50.4 50.4 50.4 Complexing agent No., g / L - 1) 34,8 1) 34,8 1) 17.4 1) 34,8 1) 34,8 1) 34,8 1) 34,8 1) 34,8 1) 34,8 Complexing agent No., g / L 2) 104.0 - - 2) 46.4 - - - - - - Silane no., G / L 1) 52.0 3) 33,1 2) 34,8 1) 34,8 1) 34,8 1) 34,8 1) 34,8 1) 69.6 1) 69.6 1) 69.6 NH ₃ - - - - - - - 17.4 17.4 17.4 Corrosion Inhibitor No., g / L - - - - - - - 1) 116.0 2) 116.0 3) 116.0 dilution factor 10 5 5 5 5 5 5 5 5 5 PH value 0.5-1 0.5-1 0.5-1 about 1.5 about 1.5 0.5-1 0.5-1 1.9-2.2 1.9-2.2 1.9-2.2 Coating weight mg / m ² : Mn - - - 44 35 - - - - - Si 4 6 6 6 6 6 6 14 19 12 Ti or Zr 28 34 36 28 35 33 36 37 50 36 P ₂ O ₅ 186 160 295 196 166 144 164 194 260 190 KK test 10 days 0% 1% 0% 0% 0% 1% nb nb nb nb KK test 20 days nb nb nb nb nb nb <1% 0% 0% 0% Salt spray test 3 days 40-60% 15-20% nb nb 5-10% 70-100% nb nb nb nb Salt spray test 4 days nb nb 10-20% 20-40% 15-25% nb <5% 0- <5% 0-1% 0- <5% Content in g / L B 21 B 22 B 23 B 24 B 25 VB 26 B 27 B 28 B 29 VB 30 substratum HDG HDG HDG HDG HDG HDG AZ AZ AZ AZ Zn 25.5 25.5 25.5 25.5 25.5 - 25.5 38.2 38.2 25.5 Mn - - - - 13.8 - - - - - Fe - - - - - 13.0 - - - - Cr - - - 13.7 13.7 - - - - - PO ₄ 111.0 111.0 111.0 139.9 132.8 240.3 111.0 166.5 166.5 111.0 P ₂ O ₅ 82.9 82.9 82.9 104.6 99.2 179.6 82.9 124.4 124.4 82.9 H ₂ TiF ₆ 72.5 72.5 72.5 72.5 72.5 162.5 72.5 72.5 72.5 72.5 Ti 21.2 21.2 21.2 21.2 21.2 47.5 21.2 21.2 21.2 21.2 F _total 50.4 50.4 50.4 50.4 50.4 113.0 50.4 50.4 50.4 50.4 Complexing agent No., g / L 1) 34,8 1) 34,8 1) 34,8 1) 42.5 1) 34,8 1) 69.6 1) 34,8 1) 34,8 1) 34,8 1) 34,8 Complexing agent No., g / L - - - - - - - - 2) 34,8 - Silane no., G / L 1) 34,8 1) 69.6 1) 34,8 1) 69.6 1) 69.6 1) 78.0 1) 34,8 1) 69.6 1) 69.6 - NH ₃ - 17.4 26.1 17.4 17.4 - 21.8 20.9 21.8 23.1 wax - - 17.4 - - - - - - - tannin - 5.0 - - - - - - - - Corrosion Inhibitor No., g / L 4) 111.0 - - - - - - - - - dilution factor 5 5 5 5 5 10 5 5 5 5 + PH 1.9-2.2 1.9-2.2 2.2-2.5 1.9-2.2 1.9-2.2 0.5-1.0 1.9-2.2 1.9-2.2 1.9-2.2 1.9-2.2 Coating weight mg / m ² : 6 13 8th 13 12 6 8th 8th 12 <1 Ti 33 32 41 38 37 42 42 40 38 37 Cr - - - 32 32 - - - - - P ₂ D ₅ 154 168 205 235 210 175 150 255 290 180 KK test 10 days nb nb nb nb nb 5-10% nb nb nb nb KK test 20 days 100% 0-25% <1-1% 0% 0% nb 0% 0% 0% 1- <5% Salt spray test 3 days <5 <10% nb nb nb nb <5-40% nb nb nb nb Salt spray test 4 days nb <1- <5% 1-20% nb nb nb nb nb nb <1% Salt spray test 7 days nb nb nb 0% 0- <5% nb <1- <5% nb nb 1-5% Salt spray test 10 days nb nb nb 0% 0-20% nb nb <1- <5% <1% nb Content in g / L VB 31 VB 32 B 33 B 34 VB 35 B 36 VB 37 B 38 B 39 B 40 substratum AZ AZ ZA Alusi Alusi HDG HDG HDG HDG HDG Zn 57.1 57.1 25.5 25.5 12.7 49.9 49.9 38.2 25.5 25.5 PO ₄ 248.8 248.8 111.0 111.0 55.5 217.6 217.6 166.5 111.0 111.0 P ₂ O ₅ 185.9 185.9 82.9 82.9 41.5 41.5 162.6 124.4 82.9 82.9 H ₂ TiF ₆ 162.5 195.0 101.5 72.5 72.5 162.5 162.5 14.5 43.5 87.0 Ti 47.5 57.0 29.7 21.2 21.2 47.5 47.5 4.2 12.7 25.4 F _total 113.0 135.6 70.6 50.4 50.4 113.0 113.0 10.1 30.3 60.6 Complexing agent No., g / L 1) 78.0 1) 78.0 1) 34,8 1) 34,8 1) 34,8 1) 117.0 1) 117.0 1) 34,8 1) 34,8 1) 34,8 Silane no., G / L - - 1) 69.6 1) 34,8 1) 34,8 1) 78.0 - 1) 34,8 1) 34,8 1) 34,8 NH ₃ 51.8 62.0 23.5 26.1 21.8 52.7 59.7 - - - dilution factor 10 10 5 5 5 10 10 5 5 5 PH value 1.9-2.2 1.9-2.2 1.9-2.2 2.2-2.5 1.9-2.2 1.9-2.2 1.9-2.2 0.5-1 0.5-1 0.5-1 Coating weight mg / m ² : Si <1 <1 13 nb nb 6 <1 6 6 6 Ti 35 36 48 nb nb 35 35 6 20 42 P ₂ O ₅ 168 185 170 nb nb 180 180 185 158 160 KK test 10 days nb nb nb nb nb nb nb <5% 0% 0% KK test 20 days <5% <5% <1% 0% 0-15% 15-25% 0-1% nb nb nb Salt spray test 3 days nb nb nb 10-20% 20-20% <5-50% 60-100% 70-90% nb <5-10% Salt spray test 4 days <1% <1-1% <5% 20% 20-20% nb nb nb 15-40% <5-15% Salt spray test 7 days <5-5% <1- <5% nb nb nb nb nb nb nb nb Content in g / L VB 41 VB 42 VB 43 VB 44 VB 45 B 46 VB 47 B 48 VB 49 substratum HDG HDG HDG HDG HDG HDG / 4 HDG / 4 HDG / 4 HDG Zn 85.7 25.5 - - 25.5 25.5 25.5 25.5 25.5 al - - 9,85,9,85 - - - - - - PO ₄ 373.1 111.0 104.0 104.0 111.0 111.0 111.0 148.0 111.0 P ₂ O ₅ 278.9 82.9 77.7 77.7 82.9 82.9 82.9 111.0 82.9 Ti chelate - 107.3 - - - - - - - H ₂ TiF ₆ 162.5 - 72.5 72.5 145.0 145.0 145.0 116.0 145.0 Ti 47.5 17.5 21.2 21.2 42.4 42.4 42.4 33.9 42.4 F _total 113.0 - 50.4 50.4 100.8 100.8 100.8 80.6 108.0 Complexing agent No., g / L 2) 104.0 1) 69.6 1) 69.6 1) 69.6 1) 69.6 1) 69.6 1) 69.6 1) 69.6 1) 69.6 Complexing agent No., g / L - - - 2) 69.6 - - - - - Silane no., G / L - - 1) 34,8 1) 34,8 1) 69.6 1) 69.6 1) 69.6 1) 69.6 - NH ₃ - - - - 34.8 34.8 34.8 38.0 - Wetting agent No., g / L - 0.3 - - - - 1) 0.75 1) 0.75 - Wetting agent No., g / L - - - - - - - 2) 1.50 - dilution factor 10 5 5 5 10 10 10 10 10 PH value 0.5-1 about 2 0.5-1 0.5-1 1.9-2.2 1.9-2.2 1.9-2.2 1.9-2.2 0-0.5 Coating weight mg / m ² : Si nb nb 6 6 nb 5 6 7 <1 Ti 32 35 36 36 nb 23 32 27 35 P ₂ O ₅ 225 270 225 245 nb 74 98 150 162 KK test 10 days 0% nb 0% 0% 10-15% 15-30% 30-70% 0% 0% KK test 20 days nb <1% nb nb nb nb nb nb nb Salt spray test 3 days 10-40% 10-30% nb <5-10% nb 15-40% 0-10% 0- <5% nb Salt spray test 4 days nb nb <5-10% nb <5-10% nb nb nb 20-30% Content in g / L VB 1 VB 2 VB 3 VB 4 VB 5 VB 6 VB 7 ** substratum HDG HDG HDG HDG ZE ZE ZE Zn 63.7 38.2 25.5 25.5 1.6 1.6 1.7 PO ₄ 231.2 166.5 111.0 111.0 18.1 18.1 10.3 P ₂ O ₅ 172.8 124.4 82.9 82.9 13.5 13.5 7.7 Ti, Zr, silane, polysiloxane, respectively 0 21.2 Ti 21.2 Ti 16.9 Ti 0 0 0 Silane no., G / L 0 1) 34,8 0 0 0 0 0 Complexing agent No., g / L 2) 69.6 0 0 0 0 0 0 H ₂ TiF ₆ 0 72.5 72.5 58.0 0 0 0 F _total 0 50.4 50.4 40.3 0 0 0 Mn 0 0 0 0 1.9 1.9 0.85 Ni 0 0 0 0 1.3 1.3 0.31 dilution factor 5 5 5 5 14 14 4 PH value 0.5-1 0.5-1 0.5-1 0.5-1 2.8-3.5 2.8-3.5 1.5-2.5 Coating weight g / m ² total nb nb nb nb 1.8 1.8 0.3 Coating weight Si nb 6 nb nb n, b. nb n, b. Coating weight Ti nb 32 32 27 nb nb nb Coating weight P ₂ O ₅ 240 165 115 105 nb nb nb After-treatment, rinsing - - - - oiled Zr-flushing none Zr pad over. As metal mg / m ² - - - - - 9 - KK test 1 day nb nb nb nb nb 1% WR 40-50% WR KK test 2 days nb nb nb nb nb <5% WR nb KK test 10 days <5% 0% 1% 30% nb nb nb KK test 21 days nb nb nb nb <1% WR nb nb Salt spray test 1 day nb nb nb nb 5-10% WR 20% WR 100% WR Salt spray test 2 days nb nb nb nb 20% WR 50-60% WR nb Salt spray test 3 days 100% 5-10% 10-30% 60-70% 40% WR nb nb ** = microphosphating WR = white rust nb = not determined Table 2: Exemplary acidities for compositions based on B 10 with reduced silane addition and measured after dilution to 60 g / L A B C PH value about 0.5 about 2 about 3 Free acid (FS, FA) 18.0 9.9 5.3 total acidity (GS, TA) 38.8 31.5 25.6 Total acid _Fischer (GSF, TAF) 17.6 16.4 15.3 S value (FS: GS, FA: TA) 0.46 0.31 0.21 S value (FS: GSF, FA: TAF) 1.02 0.60 0.35

The coatings produced according to the invention showed a coating weight in the range from 350 to 650 mg / m ² overall coverage and a layer thickness approximately in the range from 0.2 to 0.6 μm. They were produced so thin and so fast that the substances in the coatings are not sufficiently crystalline to be determined by X-ray analysis. Scanning electron micrographs of these coatings essentially reveal the topography of the cleaned metallic substrate surface. The applied coatings of the invention have not significantly topographically imaged under the scanning electron microscope. The coatings are apparently homogeneous transparent layers. Depending on the substrate type and coating, they give the metallic surface a light matte finish, just as well as without a coating or with a stronger shine. The coatings are usually without color cast.

In another series, a powder coating based on polyester in a layer thickness of about 80 microns thickness was applied to the hot-dip galvanized and pretreated sheets based on the composition of B 10. In the following cross-cut test of the painted sheets according to DIN EN ISO 2409, a value of Gt 0 always resulted before the corrosive action.

The compositions have in Comparative Example CE 1a and in Examples B 2 to B 6 each aluminum and zinc whose contents have been varied. The KK test for 10 days on the associated coatings was flawless. In the case of the examples B 7 to B 13 containing only zinc as cation, in particular PO ₄ content, Ti content, pH, complexing agent type and silane type were varied. At lower phosphate content, the corrosion protection may decrease. This may particularly affect the results of the KK test. The complexing agent 1) behaved better than the complexing agent 2). The silanes 1) and 2) behaved slightly better than the silane 3). In Examples B 14 and B 15 were as cations zinc and Manganese chosen. Care must be taken to ensure that the manganese content does not worsen the corrosion protection. Examples B 16 and B 17 compare the addition of a titanium compound with the addition of a zirconium compound. The addition of a titanium compound allows significantly higher corrosion protection on hot-dip galvanized surfaces. In Examples B 18 to B 21, various corrosion inhibitors were additionally used. The corrosion inhibitors improve the corrosion protection, with the corrosion inhibitor 4) acting somewhat less protective. The addition of tannin in Example B 22 brought no significant improvement. In Examples B 23 to B 25 and Comparative Example VB 26, the additions of cations were varied. The addition of chromium (III) improved the corrosion protection very clearly. The use of only iron cations was less successful for corrosion protection. Examples B 27 to B 29 and comparative examples VB 30 to VB 32 on Galvalume® showed excellent corrosion protection. A silane additive is not necessary for Galvalume® surfaces, but is beneficial for high corrosion protection. Example B 33 shows that good corrosion protection results can also be achieved on Galfan® surfaces. In example B 34 and comparative example VB 35 for Alusi® surfaces, care must be taken that the cation and phosphate content are not too low. In Examples B 36, B 38 to B 40 and in Comparative Examples VB 37, VB 41, VB 42, VB43 and VB44 again hot-dip galvanized surfaces were coated. In Examples B 36, B 38 to B 40 and Comparative Examples VB 37, VB 41 was worked with or without silane and with varying titanium compound content. The addition of silane or an increased titanium compound content resulted in better corrosion protection. The complexing agent 1) usually behaves better than the complexing agent 2). Exchanging titanium complex fluoride with a titanium chelate in Comparative Example VB 42 provided excellent corrosion protection for a silane-free and fluoride-free composition. In Comparative Examples VB 43 and VB 44, only aluminum was used as cations. The associated coatings appeared a bit dull. The corrosion protection was good.

The blank corrosion protection of the examples according to the invention determined in the NSS test is usually better at least by the time factor 20 or 30 than with comparable zinc-phosphated coatings. The main reason for this is assumed that the coating according to the invention is unusually closed and non-porous.

Claims (13)

1. A process for coating and passivating metal surfaces with an aqueous composition in the form of a solution or in the form of a dispersion, wherein the composition comprises
   6 to 400 g/l of at least one phosphate calculated as PO₄, 3 to 200 g/l of at least one titanium or/and zirconium compound,
   1 to 200 g/l of at least one complexing agent, selected from the group of compounds based on phosphonic acid, phytin and tannin, where the content of compounds based on phosphonic acid amounts to 0 or 1 to 200 g/l, and where the content of compounds based on phytin or/and tannin amounts to 0 or 0.05 to 30 g/l,
   3.5 to 100 g/l of cations of aluminum, chromium(III) or/and zinc or/and of at least one compound having a content of aluminum, chromium(III) or/and zinc calculated as metal, and also
   at least one silane/silanol/siloxane/polysiloxane, and wherein a wet film of the aqueous composition is dried on metal strips or sheets without the wet film or the dried film being rinsed with water.
2. The process according to claim 1, wherein the composition comprises in addition cations of iron or/and manganese or/and at least one compound having a content of iron or/and manganese.
3. The process according to claim 2, wherein the composition comprises a total content of cations of aluminum, chromium(III), iron, manganese or/and zinc or/and of at least one compound having a content of aluminum, chromium(III), iron, manganese or/and zinc in the range from 3.5 to 100 g/l, calculated as metal.
4. The process according to one of the preceding claims, wherein the composition substantially comprises only cations of aluminum, iron, manganese, titanium, zinc or/and zirconium.
5. The process according to one of the preceding claims, wherein the composition comprises a total content of at least one titanium or/and zirconium compound based on complex fluoride in the range from 1 to 200 g/l.
6. The process according to one of the preceding claims, wherein the composition comprises a content of free fluoride F_free in the range from 0.01 to 5 g/l or/and a content of total fluoride F_total in the range from 3 to 180 g/l.
7. The process according to one of the preceding claims, wherein the composition comprises a content of at least one silane/silanol/siloxane/polysiloxane in the range from 0.1 to 200 g/l, calculated on the basis of silane or polysiloxane in the particular starting compound in question.
8. The process according to one of the preceding claims, wherein the composition comprises at least one additive such as, for example, in each case at least one wetting agent, demulsifying agent, emulsifier, antifoam, corrosion-inhibitor or/and wax.
9. The process according to one of the preceding claims, wherein the composition has a pH value in the range from 0 to 10.
10. The process according to one of the preceding claims, wherein the composition has values of the free acid FA in the range from 2 to 25 points, values of total acid TA in the range from 20 to 45 points and values of total acid Fischer TAF in the range from 12 to 20 points,
11. The process according to one of the preceding claims, wherein the metal surface treated with the aqueous composition is a metal surface based on aluminum, iron, magnesium, titanium, zinc or/and tin, in particular parts, strips or/and sheets.
12. A coating prepared by a process according to one of claims 1 to 11 on a metal surface.
13. The use of the metal components coated by the process according to claims 1 to 11 in motor vehicle construction, as architectural elements in the construction sector or in the manufacture of devices and machines, such as, for example, domestic appliances.