KR19990087077A - Zinc-phosphatizing method using low concentration of nickel and / or cobalt - Google Patents

Abstract

The present invention relates to a process for the preparation of phosphatidylglycerol, which is contacted with a zinc-containing phosphatizing solution through spraying or dipping for 3 seconds to 8 minutes on a metal surface of steel, galvanized or alloy-zinc plated steel and / As a dissociation method, the phosphatizing solution used therein is characterized in that it comprises:

0.2 to 3 g / l zinc ion,

3 to 50 g / l of phosphate ions,

1 to 100 mg / l of nickel and / or cobalt ions,

One or more accelerators

And a nitrate ion of 0.5 g / l or less.

Optional components include lithium, copper and / or manganese.

Description

Zinc-phosphatizing method using low concentration of nickel and / or cobalt

The present invention relates to a method for phosphatizing a metal surface using an aqueous acid phosphatizing aqueous solution containing zinc and phosphate ions and up to 100 ppm of nickel and / or cobalt ions. The invention also relates to the use of the process as a pretreatment of the metal surface for subsequent lacquering, in particular electrophoretic lacquering or powder lacquering. The method can be applied to the surface treatment of steel, galvanized steel or alloy-galvanized steel, aluminum, aluminum-treated or alloy-aluminum treated steel.

The metal is phosphatized to produce a metal phosphate infiltration layer that is firmly adhered to the metal surface, thereby improving corrosion resistance alone and in combination with lacquers or other organic coatings, lacquer adhesion and corrosion resistance when exposed to caustic . This type of phosphatizing method has been known for a long time. Particularly suitable are low-concentration zinc phosphatizing processes in which the phosphatizing solution contains relatively low concentrations of zinc ions, for example 0.5 to 2 g / l, when pretreated prior to lacquering, especially electrophoretic lacquering. The most important feature of the low concentration zinc phosphatizing bath is that the weight ratio of the phosphate ion to the zinc ion is generally 8 or more and can have a value of up to 30.

It has been demonstrated that a phosphate layer with significantly improved anti-corrosiveness and lacquer tack can be formed by using other multivalent cations in zinc phosphate baths as well. As an example, a low-concentration zinc process involving the addition of, for example, 0.5 to 1.5 g / l of manganese ions and, for example, 0.3 to 2.0 g / l of nickel ion can be used for lacquering, for example for electro- Is widely used as a so-called three-cation method.

Nickel and cobalt, which can be used as an alternative material, are classified as hazardous in terms of toxicology and waste, so they provide the same level of effectiveness as the three cation method, but can also be carried out with much lower bath concentrations of nickel and / or cobalt A phosphatizing method is required. Recently, a phosphatizing method which does not use nickel at all has been developed. However, this method is disadvantageous in that not all the metal surfaces used in the automobile industry are equally well-surface-treated.

DE-A-2049350 discloses, as essential constituents, phosphate ions of 3 to 20 g / l, zinc ions of 0.5 to 3 g / l, cobalt ions of 0.003 to 0.7 g / l or 0.003 to 0.04 g / l 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 fluoride ions and / or, preferably, of copper ions or, preferably, of 0.05 to 3 g / l of nickel ions, Discloses a phosphatizing solution containing 2 to 30 g / l of chloride ions. Thus, in this method, a zinc / magnesium phosphatizing method is described wherein the phosphatizing solution also contains one of cobalt, copper or preferably nickel ions. The zinc / magnesium phosphatizing method of this type has not been industrially successful.

EP-B-18841 discloses in particular at least 0.2 g / l of zinc ions, from 0.4 to 1 g / l of zinc ions, from 5 to 40 g / l of phosphate ions and optionally of one or more ions selected from nickel, cobalt, calcium and manganese , Preferably from 0.2 to 2 g / l, of a zinc phosphatizing solution promoted with chlorate / nitrite. Thus, the selective nickel or cobalt concentration is greater than 0.2 g / l. In the examples, nickel concentrations of 0.53 and 1.33 g / l are cited.

EP-A-141341 relates to a phosphatizing solution containing 0.1 to 5 g / l of nickel or cobalt, with 10 to 50 g / l of zinc. This case deals with priming coatings for fixed structures such as bridges, rather than low-concentration zinc phosphatizing. EP-A-287133 describes a zinc phosphatizing solution which can optionally contain up to 0.3 g / l of cobalt. The solution contains 5 to 30 g / l of nitrite as an essential ingredient.

It is an object of the present invention to provide a phosphatizing method in which a heavy metal is omitted which achieves the effect of the 3-ion phosphatizing method for various materials used in the automobile industry. The object is achieved by a method of making a metal surface of steel, galvanized or alloy-galvanized steel and / or a metal surface of aluminum for 3 seconds to 8 minutes by spraying or impregnating, Characterized in that the phosphatizing solution used therein contains: < RTI ID = 0.0 >

0.2 to 3 g / l of zinc ions;

3 to 50 g / l of phosphate ion (calculated as PO ₄ );

1 to 100 mg / l of nickel and / or cobalt ions;

At least one accelerator selected from:

0.3 to 4 g / l of chlorate ion,

0.01 to 0.2 g / l of nitrite ions,

0.05 to 2 g / l m -nitrobenzenesulfonate ion,

0.05 to 2 g / l m -nitrobenzoate ion,

0.05 to 2 g / l of p -nitrophenol,

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

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

0.1 to 10 g / l of reducing sugars;

And a nitrate ion of 0.5 g / l or less.

The zinc concentration is preferably from about 0.3 to about 2 g / l, especially from about 0.8 to about 1.6 g / l. A zinc concentration of 1.6 g / l or more, for example 2 to 3 g / l, works only slightly advantageously in the process, while increasing the production of sludge in the phosphatizing bath. The zinc concentration can be produced when phosphatizing the galvanized surface, adding additional zinc to the performing phosphatizing bath due to pickling corrosion. Nickel and / or cobalt ions in the concentration ranges referred to as about 1 to about 100 mg / l, respectively, may be combined with a minimum possible concentration of nitrate not exceeding about 0.5 g / l, corrosion and lacquer adhesion as compared to a phosphatizing bath having a nitrate concentration of 1 or more. Preferably, the nickel concentration is about 1 to 50 mg / l and / or the cobalt concentration is about 5 to about 100 mg / l. This positively compromises between the effects of phosphatizing baths on the one hand and the requirements on wastewater treatment of wash water on the other.

German Patent Application No. 19500927.4 discloses that lithium ions of about 0.2 to about 1.5 g / l improve the anti-corrosive effect achievable using a zinc phosphatizing bath. Also, a lithium concentration of from 0.2 to about 1.5 g / l, especially from about 0.4 to about 1 g / l, positively affects the anti-corrosion effect achieved in the phosphatizing process omitting heavy metals according to the present invention. The phosphatizing solution may also contain about 0.001 to about 0.03 g / l of copper ions in place of or in addition to lithium. The copper concentration further enhances the anti-corrosion effect, especially with hydroxylamine as an accelerator. When the process according to the invention is used as an atomization process, a copper concentration of from about 0.001 to about 0.01 g / l is particularly advantageous. When used as an immersion method, a copper concentration of 0.005 to 0.02 g / l is preferred.

If the phosphatizing solution contains, in addition to or in addition to lithium and / or copper ions, additionally manganese ions, the anti-corrosive effect can be further improved. In this case, manganese is preferably present in the oxidation step 2 state. A manganese concentration of about 0.003 to about 0.1 g / l is desirable because it is a positive compromise between the efficacy of the phosphatizing bath and waste treatment requirements. A higher manganese concentration of from about 0.1 to about 4 g / l, especially from about 0.5 to about 1.5 g / l, will work more favorably with regard to the anti-corrosive effect and, if the waste treatment and sludge disposal treatment is not a problem Can be used.

Certain cation combinations are good and therefore desirable compromises between the efficacy of the phosphatizing bath and the essential waste treatment and sludge disposal treatments. In this connection, in a preferred embodiment of the present invention, a phosphatizing solution containing zinc ions, cobalt ions and copper ions in the amounts mentioned above but not containing manganese ions is used. In a second preferred embodiment, a phosphatizing bath containing zinc ions, cobalt ions and manganese ions in the amounts mentioned above, but not containing nickel or copper ions, is used. In a third preferred embodiment, a phosphatizing solution containing zinc ions, cobalt ions and lithium ions, and optionally manganese ions is used. In a fourth preferred embodiment, a phosphatizing solution containing zinc ions, nickel ions and lithium ions and optionally manganese ions in the amounts mentioned above is used.

Apart from the abovementioned cations which are introduced into the phosphate layer or at least have a positive effect on the formation of crystals in the phosphate layer, the phosphatizing bath generally contains sodium, potassium and / or ammonium ions . The expression " free acid " will be familiar to those skilled in the field of phosphatizing. The method of measuring free acids and total acids used in connection with the purposes of the present invention is illustrated. The free acid and total acid are important regulatory parameters in the phosphatizing bath because they have a large effect on the weight of the layer. A free acid value of 0 to 1.5 points for partial phosphatizing and a maximum of 2.5 points for strip phosphatizing and a total acid value of about 15 to about 30 points are within the conventional range and are also suitable for the present invention .

For phosphatizing baths intended to be compatible with different materials, it is customary to add glass and / or complex fluoride, up to 1 g / l being free fluoride, in an amount of 2.5 g / l of total fluoride. Also, the presence of this amount of fluoride advantageously acts on the phosphatizing bath according to the present invention. In the absence of fluoride, the aluminum concentration in the bath should not exceed 3 mg / l. In the presence of fluoride, higher Al concentrations may be allowed due to complex formation, where the concentration of non-complex Al should not exceed 3 mg / l. Thus, the use of a fluoride-containing bath is advantageous if the surface to be phosphatized is at least partially composed of aluminum or contains aluminum. In this case, it is advantageous to use only free fluoride, which is not a complex fluoride, preferably at a concentration of 0.5 to 1.0 g / l.

When the zinc surface is phosphatized, the phosphatizing bath need not contain a so-called promoter. However, in the case of phosphatizing a steel surface, the phosphatizing solution must contain at least one promoter. Such accelerators have often been used in the prior art as components of zinc phosphating baths. They are chemically bonded to the hydrogen produced on the metal surface as a result of attack by the acid in the pickling solution, and they are substances that are reduced. Oxidation accelerators also have the effect of oxidizing the ternary iron (II) ions released on the steel surface due to attack by the pickling solution so that they can be precipitated as iron (III) phosphate.

The phosphatizing bath according to the present invention may contain one or more of the following ingredients as promoters:

0.3 to 4 g / l of chlorate ion,

0.01 to 0.2 g / l of nitrite ions,

0.05 to 2 g / l m -nitrobenzenesulfonate ion,

0.05 to 2 g / l m -nitrobenzoate ion,

0.05 to 2 g / l of p -nitrophenol,

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

0.01 to 10 g / l hydroxylamine in free or bound form,

0.1 to 10 g / l of the reducing sugar.

When phosphatizing zinc plated steel, the phosphatizing solution should contain as little nitrate as possible. The nitrate concentration should not exceed 0.5 g / l as there is a risk of forming a so-called "speck" at high nitrate concentrations. Specification refers to the white, crater-like defects of the phosphate layer. Moreover, the adhesion of the lacquer to the galvanized surface is also compromised.

The use of nitrite as a promoter has technically satisfactory results, especially on steel surfaces. However, for reasons of industrial safety (risk of nitric acid gas production), it is recommended to avoid the use of nitrite as a promoter. This is also recommended for technical reasons when phosphatizing the galvanized surface since nitrate formation from nitrite as described above can cause problems such as specification formation and reduction of lacquer adhesion to zinc to be.

Hydroxylamine is particularly preferred as an accelerator, for environmental reasons, hydrogen peroxide and, for technical reasons, providing the possibility of a simplified formulation when more is to be added to the solution at a later stage. However, the joint use of the two promoters is undesirable because the hydroxylamine is decomposed by hydrogen peroxide. Hydrogen peroxide in a concentration of 0.005 to 0.02 g / l is particularly preferred when hydrogen peroxide is used in free or bound form as a promoter. In this case, hydrogen peroxide may be added to the phosphatizing solution as described above. However, it is also possible to use hydrogen peroxide in a bonded form as a compound which provides hydrogen peroxide in a phosphatizing bath through a hydrolysis reaction. Examples of such compounds include perborates, percarbonates, peroxosulfates, or peroxydisulfates. In addition, suitable sources of hydrogen peroxide include ionic peroxides such as alkali metal peroxides. In a preferred embodiment of the present invention, a combination of chlorate ion and hydrogen peroxide is used for phosphatizing by the dipping method. In this embodiment, the concentration of chlorate may be, for example, 2 to 4 g / l and the concentration of hydrogen peroxide may be 10 to 50 ppm.

The use of reducing sugars as promoters is known from US-A-5378292. According to the present invention, the reducing sugar may be used in an amount of about 0.01 to about 10 g / l, preferably about 0.5 to about 2.5 g / l. Examples of sugars of this type include galactose, mannose and, in particular, glucose (glucose).

In another preferred embodiment of the present invention, hydroxylamine is used as an accelerator. The hydroxylamine can be used as a free salt, as a hydroxylamine complex, as an oxime which represents a condensation product of a hydroxylamine with a ketone, or in the form of a hydroxylammonium salt. When free hydroxylamine is added to the phosphatizing bath or phosphatizing bath concentrate, the free hydroxylamine is present predominantly in the form of a hydroxylammonium cation due to the acidic nature of the solution. When used as a hydroxylammonium salt, sulfates and phosphates are particularly suitable. In the case of phosphates, acidic salts having better solubility are preferred. The hydroxylamine or the compound thereof is added to the phosphatizing bath in such an amount that the theoretical concentration of the free hydroxylamine is 0.1 to 10 g / l, preferably 0.3 to 5 g / l. In this case, it is preferable that the phosphatizing bath contains only hydroxylamine as a promoter and, if necessary, contains nitrate at most 0.5 g / l. Thus, in a preferred embodiment, phosphate baths containing no known accelerators such as nitrite, oxo-anions of halogen, peroxides or nitrobenzene sulfonates are used. As a positive additive effect, a hydroxylamine concentration of at least about 1.5 g / l is inadequately surrounded by the liquid, reducing the risk of rust forming in the portion to be phosphatized.

In practice, it has been demonstrated that accelerator hydroxylamine can be slowly inactivated if metal parts to be phosphatized in the phosphatizing bath are not introduced. Surprisingly, inactivation of the hydroxylamine has proven to be significantly slowed when at least one aliphatic hydroxycarboxylic or aminocarboxylic acid having 2 to 6 carbon atoms is added in an amount of from 0.01 to 1.5 g / l in total have. In this case, the carboxylic acid is preferably 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.

EP-A-361375 discloses the addition of 0.3 to 5 g / l, preferably 1 to 3 g / l of formic acid to the nickel-containing phosphatizing bath. Formic acid causes a stronger nickel deposit on the metal surface and / or the introduction of more nickel into the phosphate crystals. It can be expected that this effect can also be applied to cobalt. The addition of formic acid is also advantageous for the purposes of the scope of the present invention with low concentrations of nickel and / or cobalt.

When a phosphatizing method is applied to a steel surface, iron is introduced into the solution in the form of iron (II) ions. When the phosphatizing bath of the present invention does not contain a substance capable of oxidizing iron (II), the bivalent iron is transformed into a trivalent state due to oxidation in the atmosphere, and is converted into iron (III) phosphate So that it can be precipitated. This is also true, for example, when using hydroxylamine. Thus, the iron (III) concentration can be increased in the phosphatizing bath to be much higher than the contained concentration in the bath containing the oxidizing agent. As a result, iron (II) concentrations of up to 50 ppm are normal, while up to 500 ppm for a short period of time during the production cycle. In the phosphatizing method according to the present invention, the iron (II) concentration is not harmful. When manufactured using heavy water, the phosphatizing bath may contain Mg (II) and Ca (II), which are cations that give firmness, at a total concentration of up to 7 mmol / l. Mg (II) or Ca (II) can also be added to the phosphatizing bath at a concentration of up to 2.5 g / l.

The weight ratio of phosphate ion to zinc ion in the phosphatizing bath may vary widely from 3.7 to 30. A weight ratio of 10 to 20 is particularly preferred. With respect to the data on the phosphate concentration, the total phosphorus content of the phosphatizing bath is considered to be in the form of the phosphate ion PO ₄ ^3- . Thus, when calculating the amount, the fact that at pH of the phosphate bath, generally between about 3 and about 3.6, a very small fraction of the phosphate is actually present in the trivalent anion form is ignored. Instead, at this pH the phosphate can be expected to be mostly monovalent phosphate dihydrogen anion, with a small amount of undissociated phosphoric acid and divalent hydrogen phosphate anion.

Phosphatizing baths are generally sold in the form of aqueous concentrates, which can be adjusted to the required concentration by the addition of water. For reasons of stability, the concentrate contains an excess amount of free phosphoric acid, so that upon dilution with bath concentration, the initial free acid value is very high and the pH is very low. The free acid value is reduced to within the intended range by the addition of an alkali such as sodium hydroxide, sodium carbonate or ammonium. Moreover, it is known that the concentration of the free acid can increase over time due to the consumption of layer-forming cations during use of the phosphatizing bath and, in some cases, the decomposition reaction of the promoter. In this case, the free acid value should sometimes be readjusted to the target range by addition of alkali. This means that the concentration of alkali metal or ammonium ions in the phosphatizing bath can vary widely and tends to increase over the lifetime of the phosphatizing bath due to neutralization of the free acid. Thus, the weight ratio of alkali metal ions and / or ammonium ions to, for example, zinc ions, may be very low, for example <0.5 and in severe cases 0 within the newly manufactured phosphatizing bath, As the result increases over time, the weight ratio can be > 1 and up to 10 and higher values may be acceptable. Low concentration zinc phosphatizing baths generally require the addition of alkali metal ions or ammonium ions so that the free acid can be controlled so that the preferred weight ratio of PO ₄ ^3- : Zn is> 8. The same is true with respect to the ratio of alkali metal ions or ammonium ions to other bath components such as phosphate ions.

In the case of lithium-containing phosphatizing baths, the positive influence of lithium on the anti-corrosive effect is suppressed by too high a sodium concentration, so adjusting the free acid with sodium compounds should be avoided. In this case, a basic lithium compound is preferably used for free acid control. Potassium compounds are also suitable to assist in this process.

In principle, it does not matter in which form the layer forming or affecting the cation is introduced into the phosphatizing bath. However, nitrate should be avoided in order not to exceed the upper limit concentration of nitrate according to the invention. The metal ion is preferably used in the form of a compound which does not introduce external ions into the phosphatizing solution. Thus, it is most advantageous to use the metal in its oxide or carbonate form. Lithium may also be used as the sulfate and copper may preferably be used as the acetate. Forms of the phosphatizing solution particularly satisfying the ecological purpose of the present method include those containing a total of less than 0.5 g / l of other divalent cations, in addition to the zinc ions.

The phosphatizing bath according to the present invention is suitable for phosphatizing the surface of steel, galvanized or alloy-galvanized steel, aluminum, aluminum-treated or alloy-aluminum treated steel. The expression " aluminum " in the context of the present invention includes industrial aluminum alloys such as AlMg0.5Si1.4. The materials mentioned may exist side by side, as they become increasingly commonplace in the automotive industry.

Thus, the body part may be made of a pre-fabricated material, such as a material manufactured by the Bonazink method. In this case, the basic material is firstly chromatized or phosphatized and then coated with an organic resin. Then, the damaged portion of the produced layer is phosphatized by the phosphatizing method according to the present invention, or the other is phosphatized.

The method is applicable to dipping, spraying or spraying / dipping methods. Particularly, it can be used in the automobile industry, and the treatment time is usually 1 to 8 minutes, especially 2 to 5 minutes. However, it can also be used for stripping the steel structure with a treatment time of 3 to 12 seconds. When used in the strip phosphatizing method, it is desirable to match the bath concentration to the upper half of each preferred range according to the present invention. For example, the zinc concentration may be 1.5 to 2.5 g / l and the free acid concentration may be 1.5 to 2.5 points. Galvanized steel, especially galvanized steel by electrolysis, is particularly suitable as a strip phosphatizing substrate.

As is common in other known phosphatizing baths, a suitable bath temperature, regardless of the field of application, is in the range of 30 to 70 캜, preferably in the range of 45 to 60 캜.

The phosphatizing method according to the present invention is intended for treating the metal surfaces mentioned before lacquering, for example, cathodic electrophoretic lacquering, which is customary in the automotive industry. Moreover, it is suitable as a pretreatment method before powder lacquering, for example, as used in home appliances. The phosphatizing method can be regarded as a step in the technically conventional pretreatment chain. In the chain, phosphatizing is usually preceded by a cleansing / degreasing, intermediate washing and activating step, wherein the activating step is generally carried out using an activator containing titanium phosphate. After phosphatizing in accordance with the present invention, post-passivating can optionally be followed without or with intermediate cleaning. Treatment baths containing chromic acid are widely used in passivating post-treatments of this type.

However, for industrial safety reasons, there is a tendency to protect the environment and also to replace the chromium-containing passivating bath with a chromium-free bath for reasons of waste disposal. For this purpose, pure inorganic bath solutions, in particular zirconium compound based solutions, or organic-reactive bath solutions, such as those based on poly (vinylphenol), are known. In German Patent Application No. 195 11 573.2, certain phosphatizing methods are disclosed which have a pH of from about 3 to about 7, containing from 0.001 to 10 g / l of one or more of the following cation: lithium ion, copper ion and / It is known that after passivation using an aqueous solution - washing can follow. Post-cleaning of this type is also suitable for improving the anti-corrosion effect of the phosphatizing process according to the invention, especially when the phosphatizing solution does not contain copper. For this purpose, an aqueous solution containing 0.002 to 1 g / l of copper ions is preferably used. Copper is preferably used as the acetate. In particular, the post-wash solution of this type preferably has a pH of 3.4 to 6 and a temperature of 20 to 50 ° C.

An intermediate cleaning process using fully deionized water is generally performed between the post-passivating process and typically the subsequent lacquering process.

The phosphatizing method and the comparative method according to the present invention are carried out on galvanized steel sheets by electrolysis such as those used in ST 1405 steel sheet and automotive industry. The following process, which is typical in the production of automobiles, is carried out by dipping:

1. Cleanse with 2% alkaline cleanser (Ridoline 1559, Henkel KGaA) in tap water, 55 캜, 4 minutes.

2. Wash with tap water, room temperature, 1 minute.

3. Activate with 0.1% titanium phosphate-containing activator (Fixodine, C9112, Henkel KGaA) in fully deionized water at room temperature for 1 min.

4. Phosphatase with a phosphatizing bath according to Table 1, 4 min, 55 [deg.] C. In addition to the cations mentioned in Table 1, the phosphatizing bath contains sodium ions to adjust the free acid value, if necessary. The Li-containing phosphatizing bath does not contain sodium. All baths contain 0.95 g / l SiF ₆ ^2- and 0.2 g / l F ^- .

Free acid values range from 1.0 to 1.1 points and total acid values range from 23 to 25 points. The free acid value expressed in points is the consumption of 0.1 N caustic soda solution in ml per 10 ml of bath solution when titrated to pH 3.6. Likewise, the point value of the total acid is expressed in ml in terms of the pH 8.2.

5. Wash with tap water, room temperature, 1 minute.

6. Post-passivate with a chromium-free passivating agent based on 0.25% strength, complex zirconium fluoride (Deoxylyte 54 NC, Henkel KGaA) in fully deionized water, pH 4.0, 40 캜, 1 minute (Symbol in Table 1: " Zr "). Alternatively, post-passivation is carried out using a post-wash solution containing 50 mg / l of Cu (II) (as acetate), pH = 3.6 (controlled with acetic acid), temperature 45 ° C, 1 minute In the symbol: " Cu ").

7. Wash thoroughly deionized water.

8. Air-blow with compressed air.

(&Quot; layer weight &quot;) is determined by dissolving it in a chromic acid solution of 5% strength according to DIN 50942. 1.5 to 3.5 g / m &lt; ² &gt;.

The phosphatized sample sheet is coated with a negative electrophoretic lacquer of BASF (FT 85-7042). The anti-corrosive effect of galvanized steel by electrolysis is tested over five revolutions in a test under changing climatic conditions according to VDA 621-415. The results are shown in Table 1 as lacquer penetration in the case of scratch (half of the scratch width). In Table 1, "K value" is shown as a result of a stone impact test according to the VW standard (the smaller K is, the better the lacquer adhesion).

The anti-corrosion effect of the steel sheet is tested by salt spray test according to DIN 50021 (1008 hours). Table 1 shows the penetration of the lacquer in the scratch (half of the scratch width).

Phosphatizing bath, post-passivation and anti-corrosive results (steel: salt spray test; galvanized steel: change climate test) Bath Ingredient (g / l) Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Example 4 Zn (II) 1.1 1.1 1.1 1.1 1.1 1.1 1.0 PO ₄ ^3- 15 15 15 15 15 15 16 Ni (II) - 0.025 0.025 0.025 0.025 0.025 0.012 Co (II) - - 0.05 - - 0.05 - Mn (II) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Cu (II) - - - - - - - Li (I) - - - - - - 0.5 NO ₃ ^- - 10 10 - - - - H ₂ O ₂ - - - - - - - Glucose - - - - - - - (NH ₃ OH) ₂ SO ₄ 1.8 1.8 1.8 1.8 1.8 1.8 1.7 Formic acid - - - - - - - Post-wash Zr Zr Zr Zr Cu Zr Zr Lacquer penetration steel (mm) 1.3 0.8 0.8 0.8 0.7 0.7 0.9 Lacquer penetration Galvanized steel (mm) 1.7 2.2 2.0 1.6 1.6 1.4 1.4 K value 6 9 8 5 5 4 5

[Table 1b]

Bath Ingredient (g / l) Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Zn (II) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 PO ₄ ^3- 16 16 16 16 16 16 16 Ni (II) 0.012 0.012 0.012 0.012 0.025 - - Co (II) - 0.05 0.05 - - 0.05 0.05 Mn (II) 1.0 - 0.05 0.05 - - 0.05 Cu (II) - - - - - 0.01 - Li (I) 0.5 0.5 - 0.5 0.5 - - NO ₃ ^- - - - - - - - H ₂ O ₂ - - - - - - - Glucose - - - - - - - (NH ₃ OH) ₂ SO ₄ 1.7 1.7 1.7 1.7 1.7 1.7 1.7 Formic acid - - - - - - - Post-wash Cu Cu Zr Zr Zr Zr Cu Lacquer penetration steel (mm) 0.7 1.0 0.8 0.6 0.8 0.6 0.7 Lacquer penetration Galvanized steel (mm) 1.5 1.4 1.6 1.4 1.6 1.3 1.5 K value 4 6 6 5 6 4 5

[Table 1c]

Bath Ingredient (g / l) Example 12 Example 13 Example 14 Example 15 Example 16 Zn (II) 1.0 1.0 1.0 1.0 1.0 PO ₄ ^3- 16 16 16 16 16 Ni (II) - 0.012 0.012 - 0.012 Co (II) 0.05 0.05 0.05 0.02 0.05 Mn (II) - 0.05 0.05 1.0 0.05 Cu (II) - - - - - Li (I) 0.5 - - 1.0 - NO ₃ ^- - - - - - H ₂ O ₂ - 0.013 - - - Glucose - - 2.0 - - (NH ₃ OH) ₂ SO ₄ 1.7 - - 1.7 1.7 Formic acid - - - - 2.0 Post-wash Zr Zr Zr Zr Zr Lacquer penetration steel (mm) 0.8 0.9 1.0 0.8 0.7 Lacquer penetration Galvanized steel (mm) 1.4 1.5 1.5 1.4 1.4 K value 5 5 5 5 4

Claims (18)

As a phosphatizing method for bringing a metal surface of steel, galvanized or alloy-galvanized steel and / or a metal surface of aluminum into contact with zinc-containing phosphatizing solution through spraying or dipping for 3 seconds to 8 minutes , Characterized in that the phosphatizing solution used therein contains: 0.2 to 3 g / l of zinc ions; 3 to 50 g / l of phosphate ion (calculated as PO ₄ ); 1 to 100 mg / l of nickel and / or cobalt ions; At least one accelerator selected from: 0.3 to 4 g / l of chlorate ion, 0.01 to 0.2 g / l of nitrite ions, 0.05 to 2 g / l m -nitrobenzenesulfonate ion, 0.05 to 2 g / l m -nitrobenzoate ion, 0.05 to 2 g / l of p -nitrophenol, 0.005 to 0.15 g / l of free or bound form of hydrogen peroxide, 0.1 to 10 g / l of hydroxylamine in free or bound form, 0.1 to 10 g / l of reducing sugars; And a nitrate ion of 0.5 g / l or less. The method according to claim 1, wherein the phosphatizing solution contains 1 to 50 mg / l of nickel ions and / or 5 to 100 mg / l of cobalt ions. 3. The method of claim 1 or 2 wherein the phosphatizing solution also contains 0.2 to 1.5 g / l of lithium ions. The process according to any one of claims 1 to 3, wherein the phosphatizing solution also contains from 1 to 30 mg / l of copper ions. The process according to any one of claims 1 to 4, wherein the phosphatizing solution also contains 3 to 100 mg / l of manganese ions. A process according to any one of claims 1 to 4, wherein the phosphatizing solution also contains 0.1 to 4 g / l of manganese ions. The method according to any one of claims 1 to 4, wherein the phosphatizing solution contains zinc ions, cobalt ions and copper ions, and does not contain manganese ions. The method according to any one of claims 1 to 6, wherein the phosphatizing solution contains zinc ions, cobalt ions and manganese ions, and does not contain nickel or copper ions. The method of any one of claims 1 to 6, wherein the phosphatizing solution contains zinc ions, cobalt ions, and lithium ions and optionally manganese ions. The method of any one of claims 1 to 6, wherein the phosphatizing solution contains zinc ions, nickel ions and lithium ions and optionally manganese ions. A process according to any one of claims 1 to 10, wherein the phosphatizing solution also contains less than 2.5 g / l of total fluoride (each calculated as F ^- ), wherein less than 1 g / l is free fluoride . The method according to any one of claims 1 to 11, wherein the phosphatizing solution contains 5 to 150 mg / l of free or bound form of hydrogen peroxide as promoter. 11. Process according to any one of the claims 1 to 11, characterized in that the phosphatizing solution contains 0.1 to 10 g / l of free or hydroxylated form of hydroxylamine as promoter. The process according to any one of claims 1 to 13, wherein the phosphatizing solution further contains at least 0.01 to 1.5 g / l of at least one aliphatic hydroxycarboxylic acid or aminocarboxylic acid having 2 to 6 carbon atoms . 15. The process according to any one of claims 1 to 14, wherein the phosphatizing solution also contains from 0.3 to 5 g / l of formic acid. The process according to any one of claims 1 to 15, characterized in that the phosphatizing solution contains, in addition to the zinc ions, a total of less than 0.5 g / l of other divalent cations. The method according to any one of claims 1 to 16, wherein 0.001 to 10 g / l of at least one of the following cation: lithium ion, copper ion and / or copper ion is added after treatment of the metal surface with the phosphatizing solution and prior to lacquering Wherein post-passivating-washing is carried out using an aqueous solution of pH 3 to 7 containing silver ions. The method of claim 17, wherein after-washing is carried out using an aqueous solution containing from 0.002 to 1 g / l of copper ions.