SK112498A3 - Zinc-phosphatizing method using low nickel and/or cobalt concentrations - Google Patents

Abstract

Described is a method of phosphatizing steel, aluminium or galvanized or alloy-plated steel or aluminium surfaces by spraying the surface with, or dipping the surface in, a zinc-containing phosphatization solution for between 3 seconds and 8 minutes. The method is characterized in that the phosphatization solution contains 0.2 to 3 g/l of zinc ions, 3 to 50 g/l of phosphate ions, 1 to 100 mg/l of nickel or cobalt ions, as well as one or more accelerators and not more than 0.5 g/l of nitrate ions. Optional additives are lithium, copper and/or manganese.

Description

Technical field

The invention relates to a process for phosphating metal surfaces using an aqueous acidic phosphatizing solution containing zinc and phosphate ions as well as a maximum of 100 ppm nickel and / or cobalt ions. The invention further relates to the use of such processes as pretreatment of metal surfaces for subsequent painting, in particular electrochemical or powder coating. The process is applicable to the treatment of surfaces of steel, galvanized or alloyed with galvanized steel, aluminum, aluminized or alloyed steel.

BACKGROUND OF THE INVENTION

Metal phosphating aims to create firmly adhered layers of metal phosphates on metal surfaces that already improve corrosion protection and, in conjunction with lacquers or other organic layers, contribute to a significant increase in paint adhesion or corrosion resistance under lacquers. Such phosphating processes have been known for a long time. Low-zinc phosphating processes, in which the phosphatizing solutions have a relatively low zinc ion content, for example 0.5 to 2 g / l, are particularly suitable for pretreatment, in particular electrochemical coating. The more important parameter in low-zinc phosphatizing baths is the weight ratio of phosphorus ions to zinc, which is usually in the region of more than 8 and values up to 30 are acceptable.

It has been shown that by the simultaneous use of other polyvalent cations in zinc phosphatizing baths, phosphate layers can be formed with significantly improved corrosion protection and improved paint adhesion. For example, low-zinc phosphatization processes with the addition of, for example, 0.5 to 1.5 g / l manganese ions and, for example, 0.3 to 2.0 g / l nickel ions

Use as a so-called tricathion process in the preparation of metal surfaces for painting, for example, for cathodic electrochemical painting of automotive bodies.

Since nickel and alternatively used cobalt are also critically classified from the point of view of toxicology and wastewater, there is a need for a phosphating process that has similar performance to the tricathion process but suffices for a substantially lower nickel and / or cobalt concentration in the bath. More recently, phosphating processes have been developed which operate entirely free of nickel. However, these have the disadvantage that they do not reliably produce equally good results for metal surfaces used for automotive construction.

DE-A-20 49 350 discloses a phosphatizing solution which contains as essential components 3 to 20 g / l of phosphorus ions, 0.5 to 3 g / l of zinc ions, 0.003 to 0.7 g / l of cobalt ions or 0.003 up to 0.04 g / l of copper ions or preferably 0.05 to 3 g / l of nickel ions, 1 to 8 g / l of magnesium ions, 0.01 to 0.25 g / l of nitrite ions, and 0.1 to 3 g / l of fluorine ions and / or 2 to 30 g / l of chlorine ions. This process describes the following zinc-magnesium phosphating, wherein the phosphatizing solution additionally contains one of the cobalt, copper or preferably nickel ions. Such zinc-magnesium phosphating could not be established in the art.

EP-B-18 841 describes a zinc phosphate solution accelerated with chlorate and nitrite, containing inter alia 0.4 to 1 g / l of zinc ions, 5 to 40 g / l of phosphorus ions as well as optionally at least 0.2 g / l, preferably 0, 2 to 2 g / l of one or more ions selected from nickel, cobalt, calcium and manganese. Subsequently, the optional nickel or cobalt content is at least 0.2 g / l. Exemplary nickel contents of between 0.53 and 1.33 g / L are given.

EP-A-141 341 discloses phosphatizing solutions which, in addition to 10 to 50 g / l of zinc, contain nickel or cobalt in an amount of 0.1 to 5 g / l. This is not a low-zinc phosphatization, but the application of a primer on stationary structures such as bridges. EP-A-287 133 discloses a zinc phosphatizing solution which may optionally contain cobalt in an amount of up to 0.3 g / l. As essential ingredients, the solution contains 5 to 30 g / l nitrates.

3. Summary of the Invention

It is an object of the invention to provide a low heavy metal phosphating process which achieves the performance of the tricathion phosphatizing process for various materials used in automotive assembly. The problem is solved by a method of phosphating metal surfaces of steel, galvanized and alloyed with galvanized steel and / or aluminum, in which the metal surface is contacted with a zinc-containing phosphatizing solution by spraying or dipping for 3 seconds to 8 minutes, the phosphating solution containing 0.2 to 3 g / l of zinc ions to 50 g / l of phosphorous ions, calculated as PO ₄ to 100 mg / l of nickel and / or cobalt ions, one or more accelerators selected from

0.3 to 4 g / l of chlorine ions

0.01 to 0.2 g / l of nitrite ions

0.05 to 2 g / l of m-nitrobenzenesulfonic ions

0.05 to 2 g / l of m-nitrobenzoic ions

0.05 to 2 g / l of p-nitrophenol

0.005 to 0.15 g / l of hydrogen peroxide in free or bound form

0.1 to 10 g / l of hydroxylamine in free or bound form

0.1 to 10 g / l of reducing sugar as well as no more than 0.5 g / l of nitrate ions.

The zinc concentration is preferably in the range of about 0.3 and 2 g / l and in particular between about 0.8 and about 1.6 g / l. Zinc contents above 1.6 g / l, for example between 2 and 3 g / l, bring little advantage to the process, but on the other hand they can increase sludge formation in the phosphatization bath. Such zinc contents may be formed in a working phosphatizing bath when additional zinc enters the phosphatizing bath when phosphating the galvanized surfaces due to pickling. Nickel and / or cobalt ions improve, over a nominal concentration range of from about 1 to about 100 mg / l, in conjunction with as low as possible a nitrate content of not more than 0.5

-4g / l corrosion protection and paint adhesion against phosphatizing baths containing no nickel or cobalt or having a nitrate content higher than 0,5 g / l. Preferred is a nickel content in the range of about 1 to about 50 mg / l and / or a cobalt content in the range of about 5 to about 100 mg / l. In this way, an advantageous compromise is achieved between the performance of the phosphatization bath on the one hand and the requirements of the technical waste water treatment on the other.

It is known from German patent application 195 00 927.4 that lithium ions in the range of about 0.2 to 1.5 g / l improve the corrosion protection achieved by a zinc phosphatizing bath. The lithium content ranges from 0.2 to about

1.5 g / l, and in particular from about 0.4 to about 1 g / l, also have a beneficial effect on the corrosion protection achieved by the low heavy metal phosphatization process. Instead of or together with lithium, the phosphatizing solution may further comprise about 0.001 to about 0.03 g / l of copper ions. Especially in conjunction with hydroxylamine as an accelerator, such copper content leads to improved corrosion protection. When the process according to the invention is used as a spraying process, a copper content in the range of about 0.001 to 0.01 g / l is particularly preferred. When used as a dipping process, a copper content of from 0.005 to 0.02 g / l is preferred.

A further improvement in corrosion protection can be achieved if the phosphatizing solution contains, in addition to lithium and / or copper ions, additionally, manganese ions. Here, manganese in oxidation stage 2 is preferred. Here, a manganese content in the range of about 0.003 to about 0.1 g / l is a favorable compromise between the performance of the phosphatizing bath and the waste water treatment requirements and is therefore preferred. A higher manganese content in the range of about 0.1 to about 4 g / l and especially in the range of about 0.5 to about 1.5 g / l may offer additional advantages with respect to corrosion protection and is used when waste water treatment and sludge disposal is considered unproblematic.

Certain cation combinations represent a good and therefore advantageous compromise between the performance of phosphatizing baths and the necessary waste water treatment and sludge disposal. In a more preferred embodiment of the invention, a phosphatizing solution is used which contains zinc ions, cobalt ions and copper ions in the above-mentioned contents and does not contain manganese ions. In a second preferred embodiment

In embodiments, phosphatizing baths are used which contain zinc ions, cobalt ions, and manganese ions in the aforementioned contents and do not contain nickel and copper ions. In a third preferred embodiment, a phosphatizing bath is provided which comprises zinc ions, cobalt ions and lithium ions and optionally comprises manganese ions. In a fourth preferred embodiment, a phosphatizing bath is used which comprises zinc ions, nickel ions and lithium ions in the aforementioned contents and optionally contains manganese ions.

In addition to the previously mentioned cations, which will be incorporated into the phosphate layer or at least positively affect crystal growth, the phosphatizing solutions generally contain sodium, potassium and / or ammonium ions to adjust the free acid. The term free acid is apparent to those skilled in the art of phosphatization. The method for determining the free acids selected in this step as well as the total acid is given in the Examples section. Free acid and total acid are an important regulatory parameter for the phosphatizing bath because they have a large effect on the layer weight. Free acid values between 0 and 1.5 points for partial phosphating, band-pass phosphating up to 2.5 points, and total acid values between about 15 and about 30 points lie within the technically usual range and are suitable in the present invention.

For phosphatizing baths to be suitable for various substrates, it has become common to add free and / or complex bound fluoride in amounts up to

2.5 g / l of total fluoride, of which up to 1 g / l of free fluoride. The presence of such an amount of fluoride is preferred for the phosphatizing bath of the invention. In the absence of fluoride, the aluminum content of the bath should not exceed 3 mg / l. In the presence of fluoride, higher aluminum contents due to complex formation are tolerated as long as the concentration of uncomplexed aluminum does not exceed 3 mg / l. The use of fluoride-containing baths is advantageous when the surface to be phosphated is at least partially composed of aluminum or contains aluminum. In these cases, it is preferable not to add complexed fluoride, but to add only free fluoride, preferably at a concentration in the range of 0.5 to 1.0 g / l.

For phosphating zinc surfaces, it would not be necessary for the phosphatizing baths to contain so-called accelerators. However, for phosphating steel surfaces, it is necessary that the phosphatizing solution contain one or more

-6multiple accelerators. Such accelerators are known in the art as components of zinc phosphatizing baths. By this is meant compounds which chemically bind hydrogen resulting from the pickling effect of the acid on the metal surface by themselves being reduced. Furthermore, the oxidizing accelerators have the effect of oxidizing the liberated ferrous ions to trivalent in the pickling so that they can precipitate as ferric phosphate.

The phosphatizing baths of the invention may contain as one or more of the following components as an accelerator:

0.3 to 4 g / l of chlorine ions

0.01 to 0.2 g / l of nitrite ions

0.05 to 2 g / l of m-nitrobenzenesulfonic ions

0.05 to 2 g / l of m-nitrobenzoic ions

0.05 to 2 g / l of p-nitrophenol

0.005 to 0.15 g / l of hydrogen peroxide in free or bound form

0.1 to 10 g / l of hydroxylamine in free or bound form

0.1 to 10 g / l of reducing sugar

When phosphating a galvanized steel, however, the phosphatizing solution needs to contain as little nitrates as possible. The nitrate concentration of 0.5 g / l should not be exceeded, because at a higher nitrate concentration there is a danger of so-called "fiber formation". By this is meant white, cratered disorders in the phosphate layer. In addition, paint adhesion on galvanized surfaces is limited.

The use of nitrites as accelerators, especially on steel surfaces, results in technically satisfactory results. However, for reasons of occupational safety (the risk of nitrous gases), it is recommended that nitrites be abandoned as accelerators. This is also suitable for the phosphating of galvanized surfaces for technical reasons, since nitrites can form nitrates, which, as explained above, can lead to the problem of "pulp" formation and a reduction in the adhesion of the paint to the zinc.

For environmental reasons, hydrogen peroxide is particularly preferred as an accelerator, simplified options for technical reasons

Formulations for feed performance are particularly preferred as an accelerator for hydroxylamine. However, the use of both accelerators is not recommended because hydroxylamine decomposes with hydrogen peroxide. When hydrogen peroxide in free or bound form is used as accelerator, a hydrogen peroxide concentration of from 0.005 to 0.02 g / l is particularly preferred. Hydrogen peroxide may be added as such to the phosphatizing solution. However, it is also possible to use hydrogen peroxide in bound form as a compound that provides hydrogen peroxide by hydrolysis in a phosphatizing bath. Examples of such compounds are peroxy salts such as perborate, percarbonate, persulfate or persulfate. Other sources of hydrogen peroxide are ionic peroxides such as alkali metal peroxides. A preferred embodiment of the invention is that a combination of chlorine ions and hydrogen peroxide is used in dip phosphating. In this embodiment, the concentration of chlorate may be, for example, in the range of 2 to 4 g / l, the concentration of hydrogen peroxide in the range of 10 to 50 ppm.

The use of reducing sugar as an accelerator is known from US-A-5,378,292. These can be used in the present invention in an amount of between about 0.01 and about 10 g / l, preferably in an amount of between about 0.5 and about 2, 5 g / l. Examples of sugars of this kind are galactose, mannose, and in particular glucose (dextrose).

A further preferred embodiment of the invention is that hydroxylamine is used as the accelerator. Hydroxylamine can be used as the free base, as a hydroxylamine complex, as an oxime, which represents the condensation product of a hydroxylamine with a ketone, or in the form of hydroxylammonium salts. If free hydroxylamine is added to the phosphatizing bath or phosphatizing bath concentrate, it exists here, due to the acidic nature of the solution, predominantly as a hydroxylammonium cation. Sulfates as well as phosphates are particularly suitable for use as the hydroxylammonium salt. In the case of phosphates, acid salts are preferred for better solubility. The hydroxylamine or its compounds are added to the phosphatizing bath in an amount such that the recalculated concentration of free hydroxylamine is between 0.1 and 10 g / l, preferably 0.3 and 5 g / l. It is preferred that the phosphatizing bath contains hydroxylamine as the only accelerator, in all cases together with a maximum of 0.5 g / l nitrates.

Accordingly, in another preferred embodiment, phosphatizing baths are used which do not contain any of the known accelerators such as nitrites, oxoanions of halogens, peroxides or nitrobenzenesulfonates. As a positive side effect, a hydroxylamine concentration above about 1.5 g / l reduces the risk of rust formation in poorly ventilated areas of the phosphatizing parts.

In practice, it has been shown that the hydroxylamine accelerator can still be slowly inactivated when no phosphatizing metal parts are inserted into the phosphatizing bath. Surprisingly, it has been shown that hydroxylamine inactivation can be clearly retarded when one additionally is added to the phosphatizing bath. or a plurality of aliphatic hydroxy- or aminocarboxylic acids having 2 to 6 carbon atoms in a total amount of from 0.01 to 1.5 g / l. Here, preferably, the carboxylic acids are selected from glycine, lactic acid, gluconic acid, tartronic acid, malic acid, tartaric acid and citric acid, with citric acid, lactic acid and glycine being particularly preferred.

It is known from EP-A-361 375 that 0.3 to 5 g / l, preferably 1 to 3 g / l formic acid, are added to a nickel-containing phosphatizing bath. Formic acid causes enhanced nickel deposition on the metal surface and / or enhanced nickel incorporation into the phosphate crystals. It can be assumed that this also applies to cobalt. Also in the context of the present invention with low amounts of nickel and / or cobalt used, the addition of formic acid has an effect in this sense.

When the phosphatization process is applied to steel surfaces, the iron passes into solution in the form of ferrous ions. If the phosphatizing bath according to the invention does not contain any substances which are oxidative to iron (II), the divalent iron is converted to trivalent only as a result of air oxidation, so that it can precipitate as ferric phosphate. This is also the case with hydroxylamine. In this way, iron (II) contents can be formed in phosphatizing baths which are well above the contents of the baths containing oxidizing agents. In this sense, a concentration of iron (II) of up to 50 ppm is normal, and values of up to 500 ppm may occur in the short term during production. Such concentrations of iron (II) are not detrimental to the phosphatization process of the invention. When using hard water, the phosphatizing baths may further comprise cations

-9 causing a water hardness of Mg (II) and Ca (II) at a total concentration of up to 7 mmol / l. Mg (II) or Ca (II) can also be added to the phosphatizing bath in amounts up to

2.5 g / l.

The weight ratio of phosphate ions to zinc ions can vary within a wide range in phosphatization baths, as long as it lies within the range between

3.7 and 30. A weight ratio between 10 and 20 is particularly preferred. For the phosphate concentration indication, the total phosphate content of the phosphatization bath that exists as PO ₄ ³ 'is considered. Accordingly, it is neglected in the recalculation that at a pH value of a phosphatizing bath, which is usually in the range of 3 to 3.6, only a very small portion of the phosphate actually exists in the form of a trivalent negatively charged anion. At these pH values, it is much more expected that phosphate exists primarily as a single negatively charged dihydrogen phosphate anion, together with a small amount of undissociated phosphoric acid and a double negatively charged hydrogen phosphate anion.

Phosphatization baths are usually distributed as aqueous concentrates which are adjusted to the user's concentration on site by the addition of water. For stability reasons, these concentrates may contain an excess of free phosphoric acid so that when diluted to a bath concentration the free acid value is too high or the pH value too low. Addition of alkali such as sodium hydroxide, sodium carbonate or ammonia reduces the free acid value to the desired value. Furthermore, it is known that the free acid content may increase over time as the phosphatizing bath is used by the consumption of the layer-forming cations and optionally by the decomposition reaction of the accelerator. In these cases, it is sometimes necessary to reset the free acid value by adding alkali to the desired range. That is, the content of alkali metal ions or ammonium ions in the phosphatization bath can vary widely and tend to increase during use of the phosphatizing bath by neutralizing the free acid. The weight ratio of alkali metal ions and / or ammonium ions to, for example, zinc ions may therefore be very low in freshly prepared phosphatizing baths, e.g. <0.5 and in extreme cases

-10 even 0, while over time it usually increases as a result of bath adjustments, so the ratio can be> 1 and can reach values up to 10 or more. Low-zinc phosphatizing baths usually require the addition of alkali metal or ammonium ions in order to set the free acid value to the specified range at the desired PO ₄ ³ ': Zn> 8 weight ratio. Similar considerations may also be made regarding the weight ratios of alkali metal ions and / or ammonium ions to other bath components, for example phosphate ions.

In lithium-containing phosphatizing baths, it is preferable to avoid the use of sodium compounds for free acid adjustment, as the high sodium concentration suppresses the beneficial effect of lithium on corrosion protection. In this case, the preferred basic lithium compounds are used to adjust the free acid. Potassium compounds are also suitable as auxiliaries.

In principle, it is immaterial in what form the cations forming or affecting the layer enter the phosphatizing bath. However, nitrates should be avoided so that the upper limit of the nitrates of the invention is not exceeded. Preferably, metal ions of such compounds are used that do not introduce any foreign ions into the phosphatizing bath. Therefore, it is most preferred to use metals in the form of their oxides or carbonates. Lithium can also be used as sulfate, preferably copper as acetate. In this case, such phosphatizing solutions fulfill the ecological objectives particularly well, since they contain, in addition to zinc, no more than a total of 0.5 g / l of other divalent cations.

The phosphatizing baths according to the invention are suitable for the phosphatizing of surfaces made of steel, galvanized or alloyed with galvanized steel, aluminum, aluminized or alloyed steel. The term "aluminum" includes technically common aluminum alloys, such as AIMgO, 5Si1,4. Said materials can also be placed side by side - as is common in automotive assembly.

In this case, the body parts may consist of a pre-treated material, for example according to the Bonazink ^{R process} . Here, the material is first chromed or phosphatized and then coated with an organic resin layer. The phosphating according to the invention then leads to phosphating at the defective points of this pretreatment or on the untreated back sides.

The procedure is suitable for use by dipping, spraying or spray-dipping. It can be used in particular when assembling cars, where the treatment times are usually between 1 and 8 minutes, in particular 2 to 5 minutes. It is also possible to use strip phosphating in a steel plant where the treatment time is between 3 and 12 seconds. When using a strip phosphatization process, it is recommended to adjust the bath concentration in each case in the upper half of the preferred range according to the invention. For example, the zinc content may range from 1.5 to 2.5 g / l and the free acid content may range from 1.5 to 2.5 points. Galvanized steel, particularly electrolytically galvanized steel, is particularly suitable as a substrate for strip phosphatization.

As is also common in other prior art phosphatization baths, suitable bath temperatures, independently of the application range, are between 30 and 70 ° C, with a temperature range between 45 and 60 ° C being preferred.

The phosphatization process according to the invention is intended in particular to treat said metal surfaces prior to painting, for example prior to cathodic electrochemical painting, as is customary in automotive assembly. Furthermore, it is suitable as a pretreatment prior to powder coating, as used for example for household appliances. The phosphatization process must be seen as a sub-step of a technically conventional pretreatment chain. In this chain, phosphatization is typically preceded by purification / degreasing, intermediate rinsing, and activation steps, wherein the activation usually takes place with an activating agent containing titanium. The phosphatization according to the invention may optionally be followed by, with or without intermediate rinsing, a passivation treatment. Treatment baths containing chromic acid are widespread for such passivation treatment. However, there is a tendency to replace passivation baths containing chromium with chromium-free treatment baths for reasons of occupational and environmental protection and disposal. Purely inorganic bath solutions are known here, in particular based on zirconium compounds, but also organic-reactive solutions, for example based on poly (vinylphenol). It is known from German patent application 195 11 573.2 that a certain phosphatization process is followed by a passivation rinse with an aqueous solution having a pH in the range of from 3 to about 7 containing 0.001 to 10 g / l of one or

-12 several of the following cations: lithium ions, copper ions and / or silver ions. Such a rinse is suitable for improving the corrosion protection of the phosphatizing process of the invention, especially when the phosphatizing solution does not contain copper. An aqueous solution containing 0.002 to 1 g / l of copper ions is therefore preferably used. Copper is preferably used as acetate. Particularly preferred is a rinse of this type which has a pH in the range from 3.4 to 6 and a temperature in the range from 20 to 50 ° C.

As a rule, intermediate rinsing is carried out with demineralized water between this passivation and the usual subsequent coating.

DETAILED DESCRIPTION OF THE INVENTION

The phosphatization process of the invention as well as the comparative processes have been tested on ST 1405 steel sheets as well as on electrolytically galvanized steel sheets such as those used in automotive assembly. The following process step, which is customary for bodywork, was carried out as an immersion process:

1. Purification with an alkaline cleaner (Ridoline ^R 1559, Henkel KGaA), 2% water in batch, 55 ° C, 4 minutes

2. Rinse with water, room temperature, 1 minute.

3. Activation with titanium phosphate-containing activator (Fixodine ^R C9112, Henkel KGaA), feed 0.1% in demineralized water, room temperature, 1 minute

4. Phosphating in phosphatizing baths according to Table 1, 4 minutes, temperature 55 ° C. In addition to the cations listed in Table 1, the phosphatization baths contained sodium ions for free acid adjustment, if necessary. Phosphatizing baths containing Li contained no sodium. All baths contained 0.95 g / l SiF ₆ . and 0.2 g / l F.

The free acid point value was 1.0 to 1.1, the total acid was 23 to 25. The free acid point value means the consumption of 0.1 N-hydroxide

-13 sodium per ml titration with 10 ml bath solution up to pH 3,6. By analogy, the total acid point value indicates the consumption in ml up to a pH of 8.2.

5. Rinse with water, room temperature, 1 minute.

6. Additional passivation with a chromium-free passivation agent based on complex zirconium fluorides (Deoxylyte ^R 54 NC, Henkel KGaA) 0,25% in demineralised water, pH 4.0, temperature 40 ° C, 1 minute (symbol in Table 1: " Zr "). Alternatively, additional passivation was performed with a rinse solution containing 50 mg / l Cu (II) (as acetate), pH = 3.6 (adjusted with acetic acid), temperature 45 ° C, 1 minute (symbol in Table 1: "Cu ").

7. Rinse with demineralized water.

8. Drying with compressed air.

The area weight ("layer weight") was determined after dissolution in 5% chromic acid solution according to DIN 50942. It was in the range of 1.5 - 3.5 g / m ² .

BASF (FT 85-7042) was applied by cathodic dip coating to phosphatized test plates. The corrosion effect for electrolytically galvanized steel was tested in an alternating climate test according to VDA 621415 in 5 rounds. As a result, Table 1 shows the migration under lacquer on the scratch (half scratch width). At the same time, Table 1 contains the results of the VW fall test as "K-values" (the smaller the K, the better the paint adhesion).

Corrosion protection for steel sheets has been tested in a salt chamber test according to DIN 50021 (1008 hours). Table 1 shows migration under lacquer on scratch (half scratch width).

-14 Table 1: phosphatizing baths, additional passivation and corrosion protection results (steel: salt chamber test; galvanized steel: climatic rotation test)

Example 6 ABOUT_ WHAT 0,012 0.05 1 1 0.5 1 r- X " - Cu M; IN" CD Example 5 about_ CD 0,012 T about_ 1 0.5 1 1 1 1 Cu 0.7 tO Example 4 CD X " CD 0,012 T about_ 1 0.5 T 1 1 r " I Zr 6'0 T " m Example 3 X " and IN" 0,025 0.05 about 1 1 T 1 WHAT IN 1 Zr 0.7 'sr XT • M Example 2 T " ID 0,025 1 about 1 • • WHAT X " 1 Cu 0.7 1.6 it Example 1 IN" tO ID CM O o 1 CD X " • 1 1 • ° ° - x ~ 1 Zr CD Ó WHAT T " and comparison 3 X " it 0,025 0.05 1.0 1 about 1 1.8 1 Zr 0.8 2.0 what comparison 2 it 0,025 1 CD x- about 1 1 FROM N 0.8 CM cm " σ> comparison 1 X " m XT " l 1 ABOUT X " 1 1 1 1 00 IN" 1 Zr what > - IN' CD bath components (g / l) c N CO o CL from o o (Η (II) Cu (11) □ WHAT O z Cm o CM T glucose o ω N T o n T z | formic acid additional rinse migration under lacquer steel (mm) lacquer migration galvanized steel (Mm) K value

<>

-15Table 1 - continued: phosphatizing baths, additional passivation and corrosion protection results (steel: salt chamber test; galvanized steel: climatic variation test)

Example 16 1.0 | WHAT 0.012 I 0,05 | 90'0 1 1 1 1 1 X * " o CN Zr ro " M ^- Example 15 1.0 CD 1 0.02 CD in- CD T " 1 1 T r- x- 1 N CO o ' xr ID Example 14 CD T " CD x- 0,012 0.05 0.05 1 1 1 1 2.0 1 1 k_ N CJ in* LD IN" UO Example 13 CD x- CD ^r 0.012 0.05 0.05 - 1 - | 0,013 • 1 1 Zr 6'0 TQ m Example 12 CD IN" CD 1 0.05 1 1 0.5 1 • 1 r- X " 1 N CO o M; x- m Example 11 1.0 CD t— 1 0.05 0.05 1 1 1 1 1 r- T " 1 Cu 0.7 iq m Example 10 and 1.0 CD 1 I 0.05 1 0.01 1 • • T r- X " and Zr 9'0 WHAT 'C XF Example 9 1.0 CD 0,025 1 1 0.5 1 1 x ^- 1 Zr 00 o ” 1.6 CD Example 8 1.0 CD IN" 0,012 1 0.05 0.5 1 1 1 r- 1 Zr 9'0 1.4 m Example 7 and cd_ IN" CD 0,012 0.05 0.05 1 1 1 1 r- x ^- 1 Zr 8'0 what_ x- CD bath components (G / l) C N n in O Q_ Ni (II) Co (II) (Η (II) 1 Cu □ WHAT O z (N O CXI T glucose o ω 04 T o CO T z formic acid additional rinse migration under lacquer steel (mm) lacquer migration galvanized steel (mm) K value

<1

Claims (14)

PATENT CLAIMS Method for phosphating metal surfaces of steel, galvanized and alloyed with galvanized steel and / or aluminum, in which a metal surface is contacted with a phosphatizing solution by spraying or dipping between 3 seconds and 8 minutes, characterized in that the phosphatizing solution It contains 0.2 to 3 g / l of zinc ions 3 to 50 g / l phosphorus ions, calculated as PO ₄ 12 to 100 mg / l nickel and / or 1 to 100 mg / l cobalt ions 0.1 to 10 g / l of hydroxylamine in free or bound form as well as not more than 0.5 g / l of nitrate ions. Method according to claim 1, characterized in that the phosphatizing solution contains 12 to 50 mg / l nickel and / or 5 to 100 mg / l cobalt ions. Method according to one or both of Claims 1 and 2, characterized in that the phosphatizing solution additionally contains 0.2 to 1.5 g / l of lithium ions. Method according to one or more of claims 1 to 3, characterized in that the phosphatizing solution additionally contains 1 to 30 mg / l of copper ions. Method according to one or more of Claims 1 to 4, characterized in that the phosphatizing solution additionally contains 3 to 100 mg / l of manganese ions. Method according to one or more of claims 1 to 4, characterized in that the phosphatizing solution additionally contains 0.1 to 4 g / l of manganese ions. Method according to one or more of claims 1 to 4, characterized in that the phosphatizing solution contains zinc, cobalt and copper ions and does not contain manganese ions. Method according to one or more of Claims 1 to 6, characterized in that the phosphatizing solution comprises zinc, cobalt and manganese ions and does not contain nickel and copper ions. The method according to one or more of claims 1 to 6, characterized in that the phosphatizing solution comprises zinc, cobalt and lithium ions and optionally manganese ions. The process according to one or more of claims 1 to 6, characterized in that the phosphatizing solution comprises zinc, nickel and lithium ions and optionally manganese ions. Method according to one or more of claims 1 to 10, characterized in that the phosphatizing solution additionally contains fluoride in an amount of up to 2.5 g / l of total fluoride, of which up to 1 g / l of free fluoride calculated as F *. Process according to one or more of claims 1 to 11, characterized in that the phosphatizing solution additionally contains a total of 0.01 to 1.5 g / l of one or more aliphatic hydroxy- or aminocarboxylic acids having 2 to 6 carbon atoms. . Process according to one or more of Claims 1 to 12, characterized in that the phosphatizing solution additionally contains 0.3 to 5 g / l of formic acid. Process according to one or more of claims 1 to 13, characterized in that the phosphatizing solution contains not more than 0.5 g / l of other divalent cations in addition to the zinc ions.