KR19990082154A - Zinc phosphate treatment method using low concentration of copper and manganese - Google Patents

Abstract

The present invention relates to a method for treating phosphates of steel, galvanized steel or galvanized alloy steel and / or aluminum, wherein the metal surface contains the following by spraying or impregnating for a period of 3 seconds to 8 minutes. Contacting with a zinc-containing phosphate treatment solution.

0.2-3 g / l zinc ion;

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

1 to 150 mg / l manganese ions;

1 to 30 mg / l copper ions;

And one or more accelerators:

Description

Zinc phosphate treatment method using low concentration of copper and manganese

The metals are phosphated for the purpose of creating a penetrating layer of metal phosphate, which is firmly bonded on the metal surface, which alone enhances corrosion resistance and, in combination with lacquers or other organic coatings, Together, it contributes to substantial improvements in lacquer adhesion and resistance to infilteration when exposed to corrosives. This type of phosphate treatment method has long been known. In the case of pretreatment before lacquering, in particular electrophoretic lacquering, low zinc phosphate treatment methods in which the phosphate treatment solution has zinc ions of relatively low concentrations, for example 0.5 to 2 g / l ( Low zinc phosphatising processes are particularly suitable. One of the essential features of the low zinc phosphate treatment bath is the weight ratio of phosphate ions to zinc ions, which is usually larger than 8 and has a value of 30 or less.

Phosphate layers with very improved anti-corrosion and lacquer adhering properties can be formed using additional polyvalent cations in the zinc phosphate bath. For example, a low zinc process with the addition of 0.5 to 1.5 g / l manganese ions and 0.3 to 2.0 g / l nickel ions is a so-called trication method, which is used for lacquering, eg car bodies. It is widely used to provide metal surfaces for cathodic electrophoretic lacquering.

Nickel and cobalt, which can be used as an alternative, are also classified as critical in terms of toxicity and wastewater, providing treatment levels with lower concentrations of nickel and / or cobalt while providing comparable levels of performance to the tricazion method. There is a need for a phosphatising process, preferably using a treatment bath free of the two metals.

DE-A-20 49 350 is an essential component of 3 to 20 g / l phosphate ions, 0.5 to 3 g / l zinc ions, 0.003 to 0.7 g / l cobalt ions or 0.003 to 0.04 g / l copper Ions or preferably 0.05 to 3 g / l nickel ions, 1 to 8 g / l magnesium ions, 0.01 to 0.25 g / l nitrite and 0.1 to 3 g / l fluorine ions and / or 2 to 30 g A phosphate treatment solution containing / l chlorine ion is disclosed. Thus, the process describes a zinc / magnesium phosphate treatment method, wherein the phosphate treatment solution further contains one or more of cobalt, copper or preferably nickel ions. This type of zinc / magnesium phosphate treatment method has not been industrially successful.

EP-B-18 841 has in particular 0.4 to 1 g / l zinc ions, 5 to 40 g / l phosphate ions and optionally at least 0.2 g / l nickel, preferably 0.2 to 2 g / l nickel, cobalt, A chlorate / nitrite accelerated zinc phosphate treatment solution containing at least one ion selected from calcium and manganese. Therefore, the concentration of optional manganese, nickel, or cobalt is at least 0.2 g / l. In the examples, the nickel concentration is said to be 0.53 and 1.33 g / l.

EP-A-459 541 relates to a phosphate treatment solution which is essentially free of nickel and which contains in addition to zinc and phosphate 0.2 to 4 g / l manganese and 1 to 30 mg / l copper. DE-A-42 10 513 discloses a nickel free phosphate treatment solution which contains 0.5 to 25 mg / l of copper ions and hydroxylamine in addition to zinc and phosphate as accelerators. The phosphate solution further optionally contains 0.15 to 5 g / l manganese.

In the last two documents mentioned above, the phosphate treatment method satisfies the anti-corrosion protection. In practice, however, a phosphate treatment bath containing a relatively high concentration of manganese of about 1 g / l is used. The phosphate treatment bath therefore does not meet the modern ecological requirements of using the lowest possible concentration of heavy metals to discharge the minimum amount of metal-containing waste during treatment of the wash water and effluent.

The present invention relates to an aqueous, acidic phosphatising solution containing zinc and phosphate ions and to a method of phosphating a metal surface using up to 150 ppm manganese ions and up to 30 ppm copper ions. The invention further relates to the use of the above method as a method of pretreatment of the metal surface for continuous lacquering, in particular for electrophoretic lacquering or powder lacquering. .

The method is applicable to steel, galvanized steel or alloy-galvanised steel, aluminum, aluminum or aluminum-alloyed steel.

It is an object of the present invention to provide a heavy metal depleted phosphatising process, which achieves the performance of tricationic phosphate treatment on a variety of materials used in the automotive industry. This object is achieved by a process of phosphating a metal surface of steel, galvanized steel or galvanized alloy steel and / or aluminum, wherein the method sprays or impregnates the metal surface for 3 seconds to 8 minutes. contact with the zinc-containing phosphate solution by immersing, characterized in that the phosphate solution contains:

0.2-3 g / l zinc ion;

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

1 to 150 mg / l manganese ions;

1 to 30 mg / l copper ions;

And at least one accelerator selected from:

0.3 to 4 g / l chlorate ion,

0.01 to 0.2 g / l nitrite ions,

0.05-2 g / l m-nitrobenzenesulfonate ions,

0.05-2 g / l m-nitrobenzoate ions,

0.05-2 g / l of p-nitrophenol,

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

Hydroxylamine in free or bonded form from 0.1 to 10 g / l,

0.1 to 10 g / l reducing sugar

The zinc concentration is preferably between about 0.3 and about 2 g / l, in particular between about 0.8 and about 1.6 g / l. Zinc concentrations of greater than 1.6 g / l, for example 2-3 g / l, bring only very minor advantages to the process, while increasing the generation of waste water in the phosphate treatment bath. Such zinc concentration may occur in the phosphate treatment bath during operation when phosphate the zinc plated surface, where additional zinc is inserted into the phosphate treatment bath by pickling erosion. Nickel in a concentration range of about 1 to about 50 mg / l and / or cobalt ions of about 5 to about 100 mg / l contains any nickel or cobalt in combination with nitrate at the lowest possible concentration of 0.5 g / l or less. Or anti-corrosive effect and lacquer adhesion as compared to a phosphate treatment bath having a nitrate concentration of at least 0.5 g / l. This achieves a beneficial compromise between the efficiency of the phosphate treatment bath on the one hand and the requirements for the effluent treatment of the wash water on the other hand.

German patent application 195 00 927. 4 discloses that lithium ions in an amount of about 0.2 to about 1.5 g / l enhance the anti-corrosive effect achievable using a zinc phosphate treatment bath. Lithium concentrations of 0.2 to about 1.5 g / l, in particular 0.4 to about 1 g / l, also have a beneficial effect on the anti-corrosive effect obtained in the phosphate treatment process in which the heavy metals of the invention are exhausted.

If the present invention will be used as a spray method, a copper concentration of about 0.002 to about 0.01 g / l is particularly preferred. When used as the impregnation method, a copper concentration of 0.005 to 0.02 g / l is preferred.

Except for the above-mentioned cations, which are mixed with the phosphate layer or have at least a positive effect on crystal growth in the phosphate layer, the phosphate treatment bath generally contains sodium, potassium, and / or ammonium ions to form free acid ( free acid). The expression free acid is a familiar term for those skilled in the art of phosphate treatment techniques. Methods of quantifying free acid and total acid used for the purposes of the present invention are given in the Examples. Since free acid and total acid have a great influence on the weight of the layer, they are the main control factors for the phosphate treatment bath. Free acid values of 0 to 1.5 points for partial phosphate treatment, free acid values of 2.5 points or less for strip phosphatising and total acid values of about 15 to about 30 are technically within the usual ranges, and Is also suitable in the context of the present invention.

In the case of phosphate treatment baths suitably designed for various substrates, it is customary to add free and / or complexed fluorine ions in amounts of up to 2.5 g / l of total fluorine ions, with 1 g / 1 or less is free fluorine ion. The presence of fluorine ions in such amounts is also beneficial to the phosphate treatment bath according to the present invention. In the absence of fluorine ions, the aluminum concentration in the treatment bath should not exceed 3 mg / l. In the presence of fluorine ions, higher aluminum concentrations can also be tolerated due to the formation of the complex, unless the concentration of Al that does not form a complex exceeds 3 mg / l. Therefore, the use of a treatment bath containing fluorine ions is advantageous when the surface to be phosphated is at least partially composed of aluminum or contains aluminum. In this case, it is advantageous to use only free fluorine ions, not the complexed fluorine ions, preferably at a concentration of 0.5 to 1.0 g / l.

When phosphating the zinc surface, the phosphate treatment bath does not necessarily have to contain a so-called accelerator. However, when phosphating steel surfaces, the phosphate treatment solution should contain at least one accelerator. The accelerators mentioned above are conventional in the prior art as a component of the zinc phosphate treatment bath. They are understood as substances which chemically connect hydrogen produced on the metal surface as a result of attack by acids in a pickling solution, and they are reduced. Oxidizing accelerators have the effect of further oxidizing trivalent iron (II) ions released from the surface of the steel by attack of dilute acid solutions, so they can precipitate as iron (III) phosphate. .

The phosphate treatment bath according to the invention may contain one or more of the following components as accelerators:

0.3 to 4 g / l chlorate ion,

0.01 to 0.2 g / l nitrite ions,

0.05-2 g / l m-nitrobenzenesulfonate ions,

0.05-2 g / l m-nitrobenzoate ions,

0.05-2 g / l of p-nitrophenol,

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

Hydroxylamine in free or bonded form from 0.1 to 10 g / l,

0.1 to 10 g / l reducing sugar

When phosphating galvanized steel, the phosphate treatment solution should contain as little nitrate as possible. The concentration of nitrates should not exceed 0.5 g / l, because at higher concentrations there is a risk that so-called "specks" will be produced. These are white, crater-like defects inside the phosphate layer. In addition, the lacquer adhesion of the galvanized surface is impaired.

The use of nitrite as an accelerator leads to technically satisfactory results, especially on steel surfaces. However, for industrial safety reasons (risk of nitrogen gas production), the use of nitrite as an accelerator is recommended to be avoided. This is also desirable for technical reasons, as nitrates can be formed from nitrite when phosphate the zinc plated surface, which, as described above, leads to problems of spec formation and reduced lacquer adhesion to zinc.

For environmental reasons, hydrogen peroxide and for technical reasons hydroxylamine are particularly preferred as accelerators, which offer the possibility of simplified formulations when there is a greater need to be added to the solution at a later stage. However, the mutual use of these two accelerators is undesirable because hydroxylamine is degraded by hydrogen peroxide. If hydrogen peroxide is used in free or bound form as one accelerator, hydrogen peroxide at a concentration of 0.005 to 0.02 g / l is particularly preferred. In this case, hydrogen peroxide can thus be added to the phosphate solution. As a compound which provides hydrogen peroxide by hydrolysis reaction in a phosphate treatment bath, it is also preferable to use hydrogen peroxide in the form of a bond. Examples of such compounds are persalts, such as perborate, percarbonate, peroxosulfate, or peroxodisulfate. Furthermore, suitable sources of hydrogen peroxide are ionic peroxides, for example alkali metal peroxides. A preferred embodiment of the present invention involves the use of a combination of chlorate ions and hydrogen peroxide in the case of phosphate treatment by the impregnation method. In the above 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 accelerators is known from US-A-5 378 292. They may be used in amounts of about 0.01 to about 10 g / l, preferably about 0.5 to about 2.5 g / l, according to the present invention. Examples of this type of sugar are galactose, mannose and, in particular, glucose (dextrose).

Another embodiment of the present invention uses hydroxylamine as an accelerator. The hydroxylamine can be used as a free base, as a hydroxylamine complex, as an oxim representing the condensation product of hydroxyl amine and ketone, or in the form of a hydroxyl-ammonium salt. If free hydroxylamine is added to the phosphate treatment bath or phosphatising bath concentrate, it is mainly present as a hydroxylammonium cation due to the acidic nature of these solutions. Sulfate and phosphate salts are particularly suitable when used as hygisilylammonium salts. In the case of phosphates, acid salts are preferred because of their better solubility. The hydroxylamine or a compound thereof is added to the phosphate treatment bath such that the theoretical concentration of free hydroxylamine is 0.1 to 10 g / l, preferably 0.3 to 5 g / l. In this case, the phosphate treatment bath preferably contains only hydroxylamine as an accelerator, and together with nitrite of 0.5 g / l or less, if necessary. Therefore, in one preferred embodiment, the phosphate treatment bath does not contain other known accelerators, such as nitrites, oxo-anions of halogens, peroxides or nitro-benzenesulfonates. As a positive side reaction, the hydroxylamine concentration of about 1.5 g / l or more reduces the risk of rust formation on the component to be phosphated, improperly surrounded by liquid.

In practical applications, it has been found that the accelerator hydroxylamine can also be slowly deactivated unless the metal part to be phosphated is introduced into the phosphate treatment bath. Surprisingly, the addition of one or more aliphatic hydroxycarboxylic or aminocarboxylic acids having 2 to 6 carbon atoms to the phosphate treatment bath in an amount of 0.01 to 1.5 g / l in total, indicates that the deactivation of hydroxylamine can be very delayed. Figured out. In this case, the carboxylic acid is preferably selected from glycine, lactic acid, gluconic acid, tartronic acid, maleic acid, tartaric acid and citric acid, among which citric acid, lactic acid and glycine This is particularly preferred.

When a phosphate treatment process is used on the steel surface, iron enters the solution in the form of iron (II) ions. Although the phosphate treatment bath according to the present invention does not contain a substance capable of oxidizing iron (II), divalent iron can be converted to trivalent state as a result of air oxidation and precipitated as iron phosphate (III). This is the case, for example, when using hydroxylamine. Therefore, the concentration of iron (II) can be established in the phosphate treatment bath much higher than the concentration contained in the treatment bath containing the oxidant. In this context, iron (II) concentrations are usually below 50 ppm, while values up to 500 ppm during the production cycle can occur in a short period of time. In the phosphate process according to the invention, the iron (II) concentration is not impaired. When prepared using hard water, the phosphate treatment bath may additionally contain hardness-producing cation Mg (II) and Ca (II) at a concentration of up to 7 mmol / l. Mg (II) or Ca (II) may further be added to the phosphate treatment bath in an amount up to 2.5 g / l.

The weight ratio of phosphate ions to zinc ions in the phosphate treatment bath can vary between wide limits as long as it is in the range of 3.7 to 30. Particular preference is given to weight ratios of 10 to 20. Regarding the data on the phosphate concentration, all phosphorus content in the phosphate treatment bath is considered to exist in the form of phosphate ions PO ₄ ^-3 . Therefore, when calculating the ratio, ignore the fact that only a small portion of the phosphate actually exists as a triply charged anion at the pH of the phosphate treatment bath, which is generally 3 to 3.6. Furthermore, at these pHs, phosphates are expected to be present primarily as monovalently charged dihydrogen-phosphate anions, along with small amounts of undissociated phosphoric acid and divalently charged hydrogen phosphate anions.

The phosphate treatment bath is generally sold in the form of an aqueous concentrate which is adjusted to the application concentration by the addition of water at the site of use. For stability reasons, the concentrate contains excess free phosphoric acid, so upon dilution to the treatment bath concentration, the free acid value is initially too high and the pH is too low. The free acid value is lowered to the preferred range by addition of alkalis such as sodium hydroxide, sodium carbonate or ammonia. Furthermore, the concentration of free acid can increase over time during the use of the phosphate treatment bath due to the consumption of layer-forming cations and, optionally, by the decomposition reaction of the accelerator. In this case, the free acid value should be readjusted to the desired range with the addition of alkali from time to time. This means that the concentration of alkali metal ions or ammonium ions in the phosphate treatment bath is variable with wide limits and that they tend to increase throughout the life of the phosphate treatment bath as a result of neutralization of the free acid. Therefore, the weight ratio of alkali metal and / or ammonium ions to, for example, zinc ions, is very low, for example less than 0.5 (<0.5) in the newly prepared phosphate treatment bath, and may even be extremely zero. This generally increases with time as a result of the process bath maintenance process, so that the ratio may be greater than 1 (> 1) and values of 10 or more are acceptable. Low zinc phosphate treatment baths generally need to be adjusted to the desired range of preferred weight ratios by adding alkali metal ions or ammonium ions to the free acid with a weight ratio of PO ₄ ³ : Zn exceeding 8. Similar thought can be applied, for example, with regard to the ratio of other alkali metal ions or ammonium ions to phosphate ions.

In the case of lithium-containing phosphate treatment baths, the use of sodium compounds to modulate the free acid should be avoided because excessively high concentrations of sodium inhibit the desired effect of lithium on anti-corrosive effects. In this case, a basic lithium compound is preferably used to adjust the free acid. Potassium compounds are also suitable to assist in this process.

In theory, it does not matter what type of layer forming or lay-influencing cations are introduced into the zinc salt treatment bath. However, nitrates should be avoided in order not to exceed the desired upper limit of nitrate concentrations. The metal ion is preferably used in the form of not introducing foreign ions into the phosphate treatment solution. Therefore, it is most preferable to use metals in the form of their oxides or carbonates. Lithium can also be used as sulfate and copper, preferably as acetate.

The phosphate treatment bath according to the invention is suitable for phosphating the surface of steel, galvanized or galvanized alloy steel, aluminum, aluminized steel or aluminized alloy steel. The term "aluminum" as used herein includes industrially existing aluminum alloys, such as AlMg 0.5 Si 1.4. The aforementioned materials are very common in the automotive industry and may also be present side by side.

Thus, the vehicle body portion may further be made of a material already produced, for example materials produced by the Bonazink process. In this case, the base material is first chromatised or phosphated and then coated with an organic resin. The phosphate treatment method according to the invention then leads to phosphate treatment of the damaged area of the prepared layer or to phosphate treatment on the untreated opposite side.

The method is applicable to an impregnation, spraying or spraying / impregnation process. In particular, in the automobile industry, the process can be used since the treatment time of 1 to 8 minutes, in particular 2 to 5 sprays, is common. However, it can also be used for strip phosphate treatment in steel operations where the treatment time is typically 3 to 12 seconds. When used in strip phosphate treatment, it is preferred to fix the concentration of the treatment bath to the upper half of each preferred range according to the invention. For example, the zinc concentration may be between 1.5 and 2.5 g / l and the concentration of free acid may be between 1.5 and 2.5 points. In the case of galvanized steel, in particular electrolytically galvanized steel, it is more suitable as a substrate for strip phosphate treatment.

As is also the case with other known phosphate treatment baths, suitable treatment bath temperatures are in the range of 30 to 70 ° C, 45 to 60 ° C, regardless of the application.

The phosphate treatment method according to the invention is particularly intended to treat the aforementioned metal surfaces prior to lacquering, for example before cathodic electrophoretic lacquering, as is customary in the automotive industry. Furthermore, this is also suitable as a pretreatment before powder lacquer, for example for household appliances. Phosphate treatment methods are technically recognized as a step in the existing pretreatment process. In the above process, phosphate treatment usually proceeds after the steps of washing / degreasing, intermediate rinsing and activating, wherein activation is generally carried out using an activator containing titanium phosphate. After the phosphate treatment according to the invention, passivating post-treatment can optionally be carried out with or without intermediate cleaning. Treatment baths containing chromic acid are widely used for post treatment of this type of protective film.

However, there is a tendency to convert the chromium-containing protective film treatment bath into a chromium-free treatment bath for industrial safety reasons, for environmental protection, and also for waste water treatment reasons. For this purpose, pure inorganic bath solutions, in particular zirconium compounds or other organic reactive treatment bath solutions, such as those based on poly (vinylphenol), are known. From German patent application 195 11 573. 2, after a certain phosphate treatment process, passivating post rinsing with an aqueous solution having a pH of about 3 to 7 may be followed, wherein the aqueous solution is It contains from 0.001 to 10 g / l cation: lithium ions, copper ions, and / or silver ions. This type of post-cleaning is also suitable for further enhancing the anti-corrosive effect of the phosphate treatment method according to the invention. An aqueous solution containing 0.002 to 1 g / l copper ions is particularly preferably used for this purpose. Copper is preferably used as acetate. This post-cleaning solution has a pH of 3.4 to 6, and the temperature is preferably 20 to 50 ° C.

The intermediate cleaning step with complete deionized water is carried out between the post-protective film step and the subsequent lacquering process.

The phosphate treatment process and the comparative process according to the invention were carried out on ST 1405 steel plates and electrolytically galvanized steel sheets, such as those used in the automotive industry. The following process, which is customary for vehicle body manufacture, was carried out as an impregnation method:

1. Rinsing with 2% alkaline cleaner (Ridoline * 1501, Henkel KGaA) in tap water for 4 minutes at 55 ° C.

2. Rinse with tap water for 1 minute at room temperature.

3. 0.1% titanium phosphate-containing activator in deionized water for 1 minute at room temperature

4. Phosphate treatment at 55 ° C. for 4 min with phosphate treatment bath according to Table 1. In addition to the cations mentioned in Table 1, the nitrate free phosphate treatment bath contains 0.1 g / l of iron (II) and, if necessary, sodium ions to adjust the free acid value. The phosphate treatment bath containing Li does not contain sodium. All treatment baths contain 0.95 g / l SiF ₆ ^2- and 0.2 g / l F ⁻ and 1.7 g / l hydroxylammonium sulfate as accelerator.

The free acid value is 1.0-1.1 points and the total acid value is 23-25 points. The point value of free acid is 0.1 N of caustic soda consumed by 10 ml of treatment bath solution when titrated to provide a pH of 3.6. Similarly, the point value of total acid is ml consumption for setting pH to 8.2.

5. Wash at room temperature for 1 minute with tap water.

6. With a chromium-free passivating agent based on complex zirconium fluoride (Deoxylyte 54 NC, Henkel KGaA), after protective membrane for 1 minute at pH 4.0 and 40 ° C. at 0.25% concentration in complete deionized water. process.

7. Rinse thoroughly with deionized water.

8. Air-blowing with compressed air.

Area-specific weight ["layer weight": layer weight] is quantified by dissolving in a 5% concentration of chromic acid solution according to DIN 50942. These were 2.5 to 4.5 g / m 2.

The phosphate treated specimen plates are applied with a cathodic electrophoretic lacquer from BAFT (FT 85 7042). The anti-corrosive effect of electrolytically galvanized steel was tested over five cycles under varying climatic conditions in accordance with VDA 621-415. The results are given in Table 1 as the penetration of the lacquer in the scratch (half width of the scratch). Table 1 also contains the results of the stone impact test according to the VW standard (the smaller the K value the better the lacquer adhesion).

The anti-corrosive effect on the steel sheet was carried out by the salt-spray test according to DIN 50021 (1008 hours). Table 1 shows the lacquer penetration in scratches (scratch half width).

Treatment bath composition (g / l) Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Zn (II) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 PO43- 14 14 14 14 14 14 14 14 14 Mn (Ⅱ) 1.0 0.1 0.04 0.07 0.1 0.1 0.1 0.1 0.05 Cu (Ⅱ) 0.007 - 0.007 0.007 0.007 0.007 0.007 0.007 0.007 Ni (II) - - - - - 0.012 - 0.012 - Co (II) - - - - - - 0.05 0.05 - Li (II) - - - - - - - - 0.5 Lacquer Penetration Steel (mm) 0.8 1.3 0.9 0.8 0.8 0.7 0.7 0.8 0.7 Lacquer Penetration Galvanized Steel (mm) 1.4 2.2 1.6 1.6 1.5 1,4 1.5 1.4 1.4 K value 5 8 6 5 5 5 4 4 5

Claims (10)

A method for phosphating a metal surface of steel, galvanized steel or galvanized alloy steel and / or aluminum, wherein the metal surface is contacted with a zinc-containing phosphate treatment solution by spraying or impregnating for 3 seconds to 8 minutes. A process comprising the following: 0.2-3 g / l zinc ion; 3 to 50 g / l of phosphate ions (calculated as PO ₄ ); 1 to 150 mg / l manganese ions; 1 to 30 mg / l copper ions; And at least one accelerator selected from: 0.3 to 4 g / l chlorate ion, 0.01 to 0.2 g / l nitrite ions, 0.05-2 g / l m-nitrobenzenesulfonate ions, 0.05-2 g / l m-nitrobenzoate ions, 0.05-2 g / l of p-nitrophenol, 0.005 to 0.15 g / l free or bound hydrogen peroxide, Hydroxylamine in free or bonded form from 0.1 to 10 g / l, 0.1 to 10 g / l reducing sugar. The method of claim 1 wherein the phosphate treatment solution further contains 1 to 50 mg / l nickel ions and / or 5 to 100 mg / l cobalt ions. The method according to claim 1 or 2, wherein the phosphate treatment solution further contains 0.2 to 1.5 g / l of lithium ions. 4. The phosphate treatment solution of claim 1, wherein the phosphate treatment solution contains 5 to 20 mg / l of copper ions when used in the impregnation process and 2 to 10 mg / l of copper ions when used in the spraying process. How to. The method according to any one of claims 1 to 4, wherein the phosphate treatment solution further contains 2.5 g / l or less of total fluorine ions, wherein the free fluorine ion calculated by F ⁻ is 1 g / l or less. How to. The method according to any one of claims 1 to 5, wherein the phosphate treatment solution contains hydrogen peroxide in an amount of 5 to 150 mg / l in free or bonded form as an accelerator. The process according to any one of claims 1 to 5, wherein the phosphate treatment solution further contains 0.1 to 10 g / l hydroxylamine in free or bound form as an accelerator. 8. The method according to claim 7, wherein the phosphate treatment 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. The process according to any one of claims 1 to 8, wherein the phosphate treatment solution contains up to 0.5 g / l nitrate. 10. The protective film treatment post-cleaning according to any one of claims 1 to 9, wherein the metal surface is treated with a phosphate treatment solution, followed by a protective film treatment post-cleaning using an aqueous solution having a pH of 3 to 7 before lacquering. The method, wherein the aqueous solution contains a total of 0.001 to 10 g / l of at least one of lithium ions, copper ions and / or silver ions.