EP2376674B1 - Method for coating metal surfaces with an activating agent prior to phosphating - Google Patents

Description

The invention relates to a process for phosphating metallic surfaces, in which the metallic surfaces are treated before phosphating with an aqueous colloidal activator based on titanium phosphate before phosphating, and corresponding activating agents.

For many decades, phosphating has been a pretreatment process used for metallic surfaces for temporary or prolonged corrosion protection and often also for improving the adhesion of a subsequent primer or lacquer layer. The zinc-containing phosphating processes, which are referred to as so-called layer-forming (i.e., highly visible crystalline layers) phosphating processes, are of excellent quality and to date are only to a limited extent replaced by pretreatment processes with equivalent layer properties. In particular, zinc-nickel or zinc manganese-nickel phosphates are of outstanding quality and usually on aluminum, iron or zinc-rich metallic surfaces under an organic coating for reasons of corrosion protection and paint adhesion mandatory.

In particular, the zinc-containing phosphating require a prior activation for the formation of a high-quality coating, in which the clean or cleaned metallic surface with nuclei on the basis of phosphate colloid and / or phosphate particles and optionally with other substances is occupied.

Due to a good activation, the layer of the crystalline zinc-containing phosphate can be formed largely to completely closed. In addition, in many embodiments, it is advantageous if the crystalline layer is formed comparatively fine-grained and / or substantially uniformly shaped crystals. For example, due to good activation, a coating of zinc manganese nickel phosphate usually has a coating weight in the range of 1.0 to 3.5 g / m ² and phosphate crystals of often less than 12 μm mean Crystal size looks up under the scanning electron microscope. However, if the activation is omitted prior to this type of phosphating, then the resulting phosphate layer will typically have a coating weight in the range of 5 to 8 g / m ² and phosphate crystals of often more than 30 μm mean crystal size under the scanning electron microscope. In the latter case, the coat weight for the paint adhesion to the subsequent primer or lacquer layer is much too high, since if the phosphate layers are too thick, too little paint adhesion is to be expected. The consequence of the too large phosphate crystals are a lower paint adhesion, a lower corrosion resistance, a lower mechanical strength of the phosphate layer, uneven paint surfaces and a significantly higher chemical consumption. The quality of these properties is often strictly proportional.

The currently available in the market activating agents often have in series production only a period of use of about one day until they need to be enriched to a greater extent with a supplementary solution in order to remain well able to work or or until they are replaced by a new approach solution become. There are a few single activating agents on the market that have a working life of up to about four or five days by the addition of organic polymer in mass production, but which is then limited to working within five working days. The limited duration of use manifests itself primarily in the fact that the formed during zinc phosphating phosphate layers due to the changing activator over the working week in their coating weight, for example, from about 1.3 g / m ² to a coating weight of, for example, 4.5 g / m ² and thus increase in their layer thickness. This is also associated with a deterioration in corrosion resistance and paint adhesion. In principle, coating weights of about 1.0 to about 3.5 g / m ^{2 are} permissible in most automotive plants. With an even higher coating weight, however, a decrease in paint adhesion and a higher consumption of chemicals are also associated.

Therefore, it is advantageous if the change in the bath composition of the activating agent and the layer weight and the other layer properties less varies greatly over the production time. The term "bath" here stands for the treatment bath.

It is therefore desirable to develop and propose an activating agent that can be used for as many as five days (= 1 working week) and that shows only minor property fluctuations over this period (= long-term stability). If there is little variation in the coating weight of the phosphate layer produced and the average phosphate crystal size over the time of use, the quality of the activation is also considered to be good or even very good.

In the method according to the invention, values of the changes and fluctuations in the layer weight in the range from ± 0.3 to a maximum of ± 1.0 g / m ^{2 were determined} over a week, depending on the laboratory test series or plant, the layer weights always being in the range between 1 , 0 and 3.5 g / m ² remained. It is advantageous if an activating agent causes only slight property fluctuations and changes in the properties of the phosphate layer produced during the phosphating over the duration of use.

Moreover, it is advantageous if an activating agent can also be used for a longer time at a higher temperature, that is to say has a higher thermal stability. ie at temperatures in the range of 30 to 60 or possibly even in the range of 30 to 80 ° C can be used permanently. Due to such higher temperature stability, the entire process is less sensitive. Temperature fluctuations, especially in the higher temperature ranges, are then compensated and ensure a constant quality of the phosphate layer. Because if a less temperature-stable activating agent is used for a long time above its temperature stability limit, the agglomeration of the colloids is accelerated and thus degrades the activation effect much faster.

US 2008/041498 A1 describes compositions and methods for activating metallic surfaces prior to zinc phosphating with activations based on colloidal titanium phosphate and amine compound. EP 0 454 211 B1 teaches methods of applying phosphate coatings to metal surfaces by activating with a titanium phosphate activating agent followed by zinc phosphating activating the metal surfaces with an activating bath containing 0.001 to 0.060 g / L Ti, 0.02 to 1.2 g / L orthophosphate calculated as P ₂ O ₅ , containing 0.001 to 0.1 g / L of Cu and alkali compounds. EP 1 930 475 A1 refers to particulate divalent or trivalent phosphate based activators having a mean particle diameter of not more than 3 microns, metal alkoxide and stabilizer, and to methods of activating metallic surfaces prior to zinc phosphating.

It was therefore the object to propose an activating agent whose service life is better suited for mass production due to longer lasting stability and / or higher thermal stability.

The object is achieved with a method for phosphating metallic surfaces, wherein the metallic surfaces are treated prior to phosphating with an aqueous colloidal activating agent based on phosphate and titanium, wherein the activating agent selected from at least one water-soluble silicon compound having at least one organic group Bis (3-trimethoxysilylpropyl) amine and bis (3-triethoxysilylpropyl) amine, in particular, as hydrolyzed or / and condensed silane / silanol / siloxane / polysiloxane, the total content of the water-soluble silicon compounds having at least one organic group in the activating agent being in the range of 0, 0001 to 0.2 g / L, calculated respectively as silane and / or as a corresponding predominantly silicon-containing starting compound, and wherein the aqueous colloidal activating agent is selected from an aqueous colloidal activating agent (precursor A) via a powder Miges activating agent (precursor B) is prepared and then dissolved and dispersed on the metallic surfaces in water prior to application (activating agent C) or from an aqueous colloidal activating agent (precursor A) via an aqueous colloidal activating agent (precursor D) is prepared and then diluted prior to application on the metallic surfaces in water (activating agent E).

The aqueous colloidal activating agent according to the invention preferably comprises titanium phosphate, orthophosphate, alkali metal and optionally at least one stabilizing agent and / or at least one further additive. It preferably contains at least one hydrolyzed or / and condensed silane / silanol / siloxane / polysiloxane.

In the method of the present invention, the activating agent may preferably be a colloidal solution or colloidal dispersion or a powdery activating agent, the latter being dissolved and dispersed for use in a coating process. A powdered activating agent may in particular have a residual water content, optionally including water of crystallization, of between 0 and about 15% by weight. In this case, preferably at least one water-soluble silicon compound can already be present in a pulverulent activating agent and / or can only be added in water upon dissolution and dispersion of the pulverulent activating agent.

An aqueous and often colloidal activating agent such as the activating agent A may initially preferably contain a water content in the range from 5 to 90% by weight of water. For the preparation of a powdery activating agent such as the activating agent B, e.g. from an activating agent A, an initial water content of 5 to 30% by weight is preferred, for the preparation of an aqueous activating agent such as the activating agent D, e.g. From an activating agent A, an initial water content of 20 to 90% by weight is preferred.

The aqueous and usually colloidal activating agent A is an aqueous mixture which is prepared and / or prepared, for example, by mixing the respective components and optionally also by kneading and optionally with partial drying. Therefore, the aqueous colloidal activating agent A may optionally be present as a powder at the end of the preparation.

If necessary, at least one further substance, also in the dissolved and / or pulverulent state, may be added to an aqueous or pulverulent activating agent, in particular to the activating agent A, e.g. Dipotassium phosphate, disodium phosphate, potassium pyrophosphate, sodium pyrophosphate, potassium tripolyphosphate, sodium tripolyphosphate, at least one other stabilizer or / and at least one agent e.g. for pH adjustment, e.g. at least one carbonate or / and at least one borate.

In principle, various methods are possible for the preparation of an aqueous colloidal activating agent. The most important procedures are listed here.

In the process according to the invention, in a process variant 1), an aqueous to moist (= "aqueous") activating agent such as the activating agent A may preferably be used to first prepare therefrom a powdered activating agent, in particular a storable powder, such as the activating agent B, e.g. by further drying, mixing, kneading or / and granulating and then, if necessary, before applying an activating agent C on metallic surfaces, dissolve and disperse the powdered activating agent B in water - especially with stirring, which can then be applied to the metallic surfaces , The powdery activating agent B usually contains colloidal titanium phosphate in a dried state. In addition, optionally at least one substance, e.g. in each case at least one biocide, surfactant, stabilizer or / and additive for pH adjustment, in particular during dissolution and dispersion, are added.

In the process according to the invention, in a process variant 2), an aqueous colloidal activating agent according to the invention, for example the activating agent D, can be prepared or prepared, for example, from an aqueous activating agent such as the activating agent A, preferably by adding eg at least one stabilizing agent. A particularly storable aqueous colloidal activating agent such as the activating agent D can be diluted with water if necessary and can in this case to the inventive aqueous colloidal activating agent E, which can then be applied to the metallic surfaces. The dilution is preferably carried out with stirring. In addition, if appropriate, at least one substance such as in each case at least one biocide, surfactant, stabilizer or / and additive for pH adjustment, in particular during dilution, may be added.

In the method according to the invention, the aqueous colloidal activating agent according to the invention can be prepared from an aqueous colloidal activating agent (precursor A) via a powdered activating agent (precursor B) and then dissolved and dispersed in water before application to the metallic surfaces (activating agent C) or from an aqueous colloidal activating agent (precursor A) via an aqueous colloidal activating agent (precursor D) are prepared and then diluted before use on the metallic surfaces in water (activating agent E).

The activating agents may preferably contain at least one stabilizing agent. Such a stabilizer stabilizes in particular the titanium phosphate colloids. When the aqueous colloidal activating agent contains no or too little stabilizing agent, the titanium phosphate colloids may agglomerate more readily and / or more rapidly in some aqueous colloidal activating agents and / or in some situations of the activating bath, and in particular may impair the activation quality after a short time. The stability and duration of use are then limited. In some aqueous colloidal activators or / and in some situations of the activator bath, the addition or content of stabilizer is advantageous or even necessary for longer stability of the activator bath. This is especially true sometimes for a lifetime and stability of Aktivierungsmittelbades of more than 4 hours. Table 1: Overview of the various activating agents, their precursors, their contents and their state: activating agent made of Si compound Titanium phosphate colloids stabilizer usual concentration Status A - optional Yes* optional higher concentrated watery or moist B A optional dried up yes * optional higher concentrated powder C A over B Yes Yes optional Treatment bath ⁺ aqueous D A optional Yes Yes higher concentrated aqueous e A over D Yes Yes Yes Treatment bath ⁺ aqueous * Usually instead of the usual bath concentration, it can also be a concentrate

Here, the aqueous colloidal activating agents of the invention such as the activating agents C and E contain at least one water-soluble silicon compound having at least one organic group, while an activating agent such as e.g. the activating agents A, B and D in some process variants contain at least one water-soluble silicon compound having at least one organic group.

For the purposes of this application, the terms "colloid (s)" and "colloidal" designate only titanium phosphate colloids or corresponding contents, since only these colloids have a significant activating effect for a subsequent phosphating. An aqueous activating agent such as the activating agent A, C, D or / and E typically contains dissolved and often colloidal components. Its particles are typically partially or completely in the particle sizes of the otherwise conventionally used term "colloidal" (eg finely divided particles with particle sizes approximately between 1 and 100 nm or between 1 and eg 300 nm). You can However, sometimes also have a small proportion of particle sizes up to just over 1 micron size. The particle sizes of the activating agent were measured using a Zetasizer Nano ZS from Malvern Instruments Ltd. certainly. In this case, the pH values and conditions of the activator to be measured were chosen so that 0.1 g / L of solids and active ingredients were used without further additives in the state of a bath solution. In many embodiments, the particle size distribution of an activating agent is polydispersed, ie in a bimodal or multimodal particle size distribution.

The ready-for-use colloidal activating agents according to the invention, such as the activating agents C and E, are usually present in the concentration of the treatment bath of an activating agent bath, occasionally occasionally also in a slightly elevated concentration, before the concentration of the activator bath is adjusted by dilution with water. The activating agents C are commonly referred to in the art as "powder activation", while the activating agents E are commonly referred to as "liquid activating". An activating agent in a preliminary stage of the production process of an activating agent such as the activating agent A, B and D is usually in a higher concentration than that of the treating bath of an activating agent bath. Preferably, they are highly concentrated. They are usually precursors of the aqueous colloidal activating agents according to the invention, which are used in the concentration of the treatment bath of an activating agent bath.

Preferably, a powdered activating agent according to the invention, such as the activating agent B, is present as a powder, optionally as a granulated powder. In principle, it can also be produced by spray drying. It is largely or completely dry. A pulverulent activating agent preferably has a powder particle size distribution essentially in the range from 1 to 1000 μm, particularly preferably in the range from 10 to 500 μm, in substantially dry state determined by sieve analysis with sieves in the range of about 500 to about 25 μm mesh size. It preferably has an average powder particle size in the range from 25 to 150 μm, particularly preferably in the range from 40 to 80 μm. The powdered activating agent is preferably present in a readily free-flowing form. in this connection it is advantageous to make sure that the moisture content of the powder is not too high. In addition, it is advantageous if it is well dispersed and dissolved well when stirred in water, during dissolution and / or during dispersion. In the case of a pulverulent activating agent, such as the activating agent B, the colloids are preferably dried up. When dissolving a powdered activating agent such as the activating agent B, the colloids are in high quality and usually in sufficient quantity.

The aqueous colloidal activating agents of the invention, e.g. the activating agents C or / and E are typically present in a colloidal solution and / or colloidal suspension. Their titanium phosphate particles are typically partially or completely colloidal.

An aqueous colloidal activating agent A differs from an aqueous colloidal activating agent C in the concentration or / and in the phase inventory and optionally also in the overall chemical composition. The aqueous colloidal activating agent A often also does not contain any substantial content of stabilizing agent, but often substantially or even only at least one orthophosphate and titanium phosphate among the phosphates. It is often highly concentrated.

It has surprisingly been found that the addition of at least one stabilizing agent to an aqueous and optionally colloidal activating agent such as the activating agent A, C, D or / and E leads to a partially very marked increase in the stabilization and the longevity of the activating agent.

If an aqueous colloidal activating agent according to the invention, in particular an activating agent C or / and E, is unstable, then it is advantageous or even necessary to add stabilizing agents. The stability is based on the low or high tendency of the colloids to agglomerate or to lack colloids. Agglomerated or missing colloids have a poor or no activation effect.

An aqueous colloidal activating agent of the present invention, such as the activating agent C containing no stabilizing agent, preferably differs from an activating agent of a precursor such as the activating agent A due to the dilution and is usually in a somewhat more stable state because the agglomeration of the colloids is lower. An inventive aqueous colloidal activating agent such as the activating agent C with at least one stabilizing agent differs from an activating agent of a precursor such as the activating agent A in particular by a significantly increased stability and thus by overall significantly improved properties of the coating process and the phosphate coating.

The aqueous colloidal activator D is often a concentrate. It contains colloids in the aqueous phase. Its stability is usually ensured by at least one stabilizing agent.

An aqueous colloidal activating agent according to the invention, e.g. the activating agent E may be prepared from an aqueous more highly concentrated colloidal activating agent of a precursor such as the activating agent D by dilution with water and optionally by adding at least one substance, e.g. in each case at least one biocide, surfactant, stabilizer or / and additive for pH adjustment are produced.

The concentrates and baths of an aqueous colloidal activating agent according to the invention, such as the activating agents C and E, often have quite similar or identical properties to one another. The properties of the phosphate layers upon previous activation with an aqueous colloidal activating agent of the invention such as the aqueous activating agent C or E are often quite similar or the same among themselves. The suitability and quality of the activating agent bath can be determined in particular by means of coating weight, visually discernible uniformity of the zinc phosphate layer, degree of coverage with zinc phosphate layer, corrosion test results or / and paint adhesion test results.

Preferably, an activating agent such as the activating agent A, B, C, D or / and E as the main ingredient or as an essential ingredient contains at least one phosphate such as e.g. in each case at least one sodium, potassium or / and titanium-containing phosphate, in particular as main constituents, sodium and / or potassium orthophosphate (e) and at least one titanium-containing phosphate.

Preferably, the phosphates are in an aqueous colloidal activating agent such as the activating agent A, C, D or / and E in the form of titanium phosphate, titanyl phosphate, disodium phosphate and / or dipotassium phosphate. In addition, an aqueous colloidal activating agent such as in particular the activating agent A, C, D or / and E may optionally also have a content of at least one stabilizing agent such as pyrophosphate and / or tripolyphosphate.

In the process of the present invention, the content of an aqueous activating agent such as the activating agent A, C, D or / and E of phosphate may be calculated as phosphate compounds preferably in the range of 0.05 to 400 g / L and more preferably in the range of 0.10 to 280 or from 0.20 to 200 g / L or in the case of a pulverulent activating agent such as activating agent B in the range from 0.5 to 98% by weight and in particular in the range from 3 to 90 or from 10 to 80% by weight ( each for concentrates and baths).

In the process of the present invention, the content of an aqueous activating agent such as the activating agent A, C, D or / and E of phosphate may be calculated as PO ₄ preferably in the range of 0.005 to 300 g / L and more preferably in the range of 0.010 to 200 or 0.020 to 100 g / L or in the case of a pulverulent activating agent such as the activating agent B in the range of 0.1 to 80 wt .-% and in particular in the range of 1 to 65 or from 10 to 50 wt .-% (in each case for concentrates and baths ).

In the case of incorporating cleanser with a silicate content from one of the previous baths, this silicate content and this silicate do not belong to the term "silicon compound" in the context of this application.

Optionally, in some embodiments, the at least one silane / silanol / siloxane / polysiloxane is not included in an aqueous or powdered activating agent precursor such as the activating agent A, B or D and then becomes effective only in the preparation of an aqueous colloidal activating agent of the invention such as the activating agent C or E. added.

In the process of the present invention, the total content of the water-soluble silicon compounds having at least one organic group in an activator precursor such as activator A, B or D may be either about zero or in an aqueous activator such as activator A, C, D or / and E is preferably 0 , 0001 to 50 g / L and in particular 0.001 to 20 g / L, in particular for coating on the metallic surfaces 0.001 to 0.2 g / L, or in a powdered activating agent as in the activating agent B preferably about zero or 0.001 to 25 wt .-% and in particular 0.01 to 5 wt .-%, calculated in each case as silane and / or as a corresponding mainly present silicon-containing starting compound (respectively for concentrates and baths).

The term "silane" or "silanes / silanols / siloxanes / polysiloxanes" in the context of this application is used here for silanes, silanols, siloxanes, polysiloxanes and their reaction products or derivatives, which are often "silane" mixtures. It is also possible to add a polysiloxane. Particularly preferred is the addition of at least one silane having at least one organic group, where it is common to speak of "silane", since it often does not know whether the often purchased "silane" at least one silane, at least one silanol, at least a siloxane, at least one polysiloxane or any mixture of these substances. Even with self-modified "silanes", it is often impossible or only possible with extremely great effort to determine which substances are present at a certain stage of production or after storage or after addition to a solution or suspension. Due to the often complex chemical reactions that occur in this case, and complex analyzes and work, the respective other silanes or other reaction products can usually not be specified.

In the process according to the invention, as the silicon compound in an activating agent such as in the activating agent A, B, D or / and E, it is preferable to contain at least one hydrolyzable or / and at least one at least partially hydrolyzed silane.

In the process according to the invention, the activating agent contains as silicon compound preferably at least one partially or completely hydrolyzed silane / silanol / siloxane or / and optionally also condensed silane / silanol / siloxane / polysiloxane.

In the process of the present invention, the content of titanium in an aqueous activating agent such as the activating agent A, C, D or / and E may preferably be in the range of 0.0001 to 10 g / L, more preferably in the range of 0.001 to 5 or 0.005 to 1 g / L or in a powdered activating agent such as the activating agent B preferably be about zero or in the range of 0.001 to 10 wt .-% and in particular in the range of 0.005 to 2 or from 0.01 to 1 wt .-% (in each case for concentrates and baths).

In the process of the present invention, the total content of cobalt, copper or / and nickel in an aqueous activating agent such as the activating agent A, C, D or / and E may preferably be about zero or in the range of 0.00001 to 0.1 g / L and in particular in the range of 0.0005 to 0.05 or from 0.01 to 0.02 g / L or in a powdered activating agent such as the activating agent B preferably be about zero or in the range of 0.0001 to 2 wt. % and in particular in the range of 0.001 to 0.8 or from 0.01 to 0.4 wt .-% (in each case for concentrates and baths). A content of cobalt, copper or / and nickel can contribute to the refinement of the phosphate layer and has a bactericidal effect.

In the process according to the invention, a weight ratio of the contents of titanium to those of water-soluble silicon compounds having at least one organic group (calculated in each case as silane and / or as corresponding silicon-containing starting compound) is in the range of (0.3-2.6): 1 as good, in the range of (0.2 - 3.0): 1 as at least sufficient.

In the method according to the invention, the total content of sodium and / or potassium in an aqueous activating agent such as the activating agent A, C, D or / and E preferably in the range of 0.005 to 300 g / L and in particular in the range of 0.01 to 200 or from 0.02 to 100 g / l or in a powdered activating agent such as the activating agent B, preferably in the range from 0.1 to 70% by weight and in particular in the range from 1 to 60 or from 10 to 50% by weight. (each for concentrates and baths).

In the method according to the invention, the activating agent may preferably also contain a content of at least one biocide, wetting agent, softening agent, complexing agent, sequestering agent, stabilizing agent or / and markers.

In the method according to the invention, the total content of at least one labeling ion and / or on at least one labeling compound (marker due to their color, their fluorescence and / or their chemical and / or physical analyzability) such. based on lithium, lanthanide (s), yttrium or / and tungsten, as a dye marker and / or as a fluorescent marker in an aqueous activating agent such as the activating agent A, C, D or / and E preferably be about zero or in the range of 0.0001 to 100 g / L and in particular in the range of 0.001 to 10 or from 0.01 to 1 g / L or in a powdered activating agent such as the activating agent B preferably be about zero or in the range of 0.001 to 20 wt .-% and in particular in the range of 0.01 to 10 or from 0.1 to 1 wt .-% (in each case for concentrates and baths).

In addition, an activating agent such as the activating agent A, B, C, D or / and E may also optionally in each case at least one softening agent (= water hardness binders) such as in each case at least one / a dicarboxylic acid, tricarboxylic acid, higher carboxylic acid, polycarboxylic acid, oxydicarboxylic acid , Oxytricarbonsäure, higher oxycarboxylic acid, polyoxycarboxylic acid, phosphonic acid, diphosphonic acid triphosphonic acid, polyphosphonic acid, phosphonic acid esters or / and derivatives thereof such as hydroxyphosphonic acid and / or derivatives thereof are added or / and contain. As phosphonic acid, for example, HEDP = (1-hydroxyethylidene) diphosphonic acid is particularly preferred. Such compounds serve in particular as complexing agents and / or as sequestering agents. In the process according to the invention, the content of softening agents in an aqueous activating agent such as the activating agent A, C, D or / and E may preferably be zero or in the range of 0.0001 to 50 g / L and in particular 0.001 to 20 g / L in a powdered activating agent such as the activating agent B preferably be about zero or in the range of 0.001 to 25 wt .-% and in particular 0.01 to 5 wt .-% (in each case for concentrates and baths).

In addition, an activating agent such as the activating agent A, B, C, D or / and E may optionally also contain in each case at least one addition of at least one stabilizing agent. Such a stabilizer stabilizes the titanium phosphate colloids. The stabilizing agent may comprise at least one substance, e.g. at least one based on at least one organic polymer, organic Copolvmer, pyrophosphate, tripolyphosphate and / or phosphonate or be. In particular, the activating agent preferably contains as stabilizing agent in each case at least one / an anionically modified polysaccharide, water-soluble organic copolymer, such as e.g. especially one based on acrylate, ethylene or / and polyelectrolyte, carboxylic acid, phosphonic acid, diphosphonic acid, triphosphonic acid, polyphosphonic acid, polyelectrolyte or / and derivatives thereof, such as e.g. Carboxylic acid esters, phosphonic acid esters or / and derivatives thereof. The stabilization takes place via electrostatic and / or steric stabilization. Although orthophosphates also often have a certain, but not a high stabilizing effect, they are not referred to as stabilizing agents for the purposes of this application.

In the process of the present invention, the content of stabilizing agents in an aqueous activating agent such as the activating agent A, C, D or / and E may preferably be about zero or in the range of 0.0001 to 300 g / L and more preferably 1 to 200 g / L or in a powdered activating agent such as the activating agent B preferably be about zero or in the range of 0.001 to 80 Wt .-% and in particular 1 to 60 wt .-% are (in each case for concentrates and baths).

In the process according to the invention, an aqueous activating agent such as an activating agent A, C, D or / and E may also have a content of a detergent mixture, of at least one surfactant or / and of at least one hydrotrope such as e.g. in each case at least one alkane sulfate, alkanesulfonate or / and glycol or added to the activating agent. Suitable surfactants are in principle all amphoteric, nonionic, anionic and cationic surfactants in question. In the process according to the invention, the content of each of at least one detergent mixture, surfactant or / and hydrotrope in an activating agent such as the activating agent A, C, D or / and E may preferably be about zero or in the range of 0.001 to 100 g / L and in particular Range from 0.005 to 50 or from 0.01 to 10 g / L or in a powdered activating agent such as the activating agent B preferably be about zero or in the range of 0.01 to 99 wt .-% and in particular in the range of 0, 05 to 90 or from 0.1 to 80 wt .-% (each for concentrates, baths and activating detergents).

In addition, a wide variety of substances can be used to adjust the pH and / or to buffer the chemical system, preferably at least one borate or / and at least one carbonate. Particularly preferred are alkali metal compounds such as e.g. at least one alkali borate or / and at least one alkali carbonate. The content of these compounds can vary within wide limits. It is preferably either about zero or is often 0.1 to 200 g / L or preferably 1 to 100 g / L in an aqueous activating agent such as the activating agent A, C, D or / and E or is in a powdered activating agent such as Activating agent B is preferably about zero or is 0.01 to 95 wt .-% and in particular 0.1 to 90 or 1 to 80 wt .-% (respectively for concentrates, baths and for activating detergents).

In the method according to the invention, the activating agent may preferably also contain a content of at least one biocide. In the inventive Method, the content of biocide (s) in an activating agent such as the activating agent A, B, C, D or / and E preferably be about zero or in the range of 0.0001 to 2 g / L and in particular in the range of 0.005 to 0 , 3 or from 0.01 to 0.05 g / L or in an activating agent such as the activating agent B preferably be about zero or in the range of 0.01 to 10 wt .-% and in particular in the range of 0.05 to 2 or from 0.1 to 1.5 wt .-% (each for concentrates and baths).

Preferably, the pH in an aqueous activating agent such as the activating agent A, C, D and / or E is in the range of 7 to 13, more preferably in the range of 8 to 12 or 8.5 to 11. In embodiments, the pH may be Value also be less than 7, if it does not come to disturbing precipitations in Aktivierungsmittelbad, or even be greater than 13, if this bath does not attack the system parts too much.

In the method of the present invention, an aqueous colloidal activating agent of the present invention such as the activating agent C and / or E may be preferably applied at a temperature in the range of 10 to 80 ° C on the metallic surfaces, more preferably in the range of 15 to 60 or 20 to 50 ° C.

In the method according to the invention, the activating agent according to the invention may preferably be applied to the metallic surfaces by flooding, swelling, spraying, dipping or / and rolling on and optionally squeezing. In most embodiments, the activating agent is applied by spraying or dipping.

In the method according to the invention, the metallic surfaces may preferably be cleaned, degreased or / and pickled prior to activation and subsequently and / or optionally rinsed with water in between. In many embodiments it is necessary to subsequently rinse with water after cleaning, degreasing or / and pickling.

In the method according to the invention, the metallic surfaces can preferably be rinsed with water after activation and before phosphating. In many embodiments, this rinse is optional.

In the method according to the invention, the metallic surfaces may preferably be phosphated after rinsing, rinsed and / or with at least one organic coating such as e.g. at least one primer, at least one lacquer, at least one adhesive carrier and / or at least one adhesive are provided. This can be dried, rinsed or rinsed if necessary after the application of a coating and then dried.

The layer weight of the produced zinc phosphate layer has been found to be satisfactory in the tests at values of 1.5-3 g / m ² , at values of> 3 - <4 g / m ² and at values between about 1 and 1.5 and between 4 and 4.5 g / m ² mostly proved to be satisfactory. However, the coating weight is not the only criterion for evaluating the quality of an activating agent bath. Rather, the visually recognizable uniformity of the zinc phosphate layer, the degree of coverage with zinc phosphate layer, the corrosion test results and / or the paint adhesion test results can also be used here. In addition, the activating agents according to the invention have usually proven to be good if their activating effect turned out to be good or very good over at least 120 h, which is measurable in particular on the coating weight. A good to satisfactory activating effect could even be achieved over more than 300 hours in the case of activating agent baths according to the invention. Because when the activating effect decreases, the increase in the coating weight of the zinc phosphate layer to values above 3.5 g / m ² and at the macroscopically observable degree of coverage with a zinc phosphate layer or on metallically shiny parts or at points with a rust attack are particularly evident.

In principle, surfaces of all types of materials-if appropriate also of several different materials adjacent to one another and / or one after the other in the process-can be used as surfaces, in particular all types of metallic materials. Among the metallic materials are basically all kinds of metallic materials are possible, in particular those of aluminum, iron, copper, titanium, zinc, tin or / and alloys containing aluminum, iron, steel, copper, magnesium, nickel, titanium, zinc or / and tin, wherein their use can also be adjacent or / and successively. If appropriate, the material surfaces can also be precoated or / and be, for example, with zinc or an alloy containing aluminum or / and zinc.

The object is also achieved with an aqueous colloidal activating agent based on titanium phosphate and at least one other titanium-free phosphate for the treatment of metallic surfaces before phosphating, in which the activating agent comprises at least one water-soluble silicon compound having at least one organic group selected from bis (3) trimethoxysilylpropyl) amine and bis (3-triethoxysilylpropyl) amine, in particular, as hydrolyzed or / and condensed silane / silanol / siloxane / polysiloxane, the total content of the water-soluble silicon compounds having at least one organic group in the activating agent being in the range from 0.0001 to 0, 2 g / L, calculated in each case as silane or / and as a corresponding mainly present silicon-containing starting compound.

The aqueous colloidal activating agent according to the invention is preferably an aqueous colloidal activating agent C which has been prepared from an aqueous colloidal activating agent A via a powdered activating agent B and in which the pulverulent activating agent B has then been dissolved and dispersed in water for application, or an aqueous colloidal activating agent E prepared from an aqueous colloidal activating agent A via an aqueous colloidal activating agent D, wherein the aqueous activating agent E was prepared by dilution with water, the term "colloidal" being based only on titanium phosphate colloids.

Incidentally, the activating agent may preferably have a composition according to one of the method claims, in particular at least one stabilizing agent.

With the aqueous activating agent according to the invention, to the knowledge of the applicant, it is surprisingly possible for the first time to achieve bath life which can be used well without or without the addition of concentrates or / and of supplementing agents for more than 120 h. In this case, either no addition or at most the addition of concentrates and / or supplementation is added up to the amount of bath bath discharged low over the bath life and thereby achieves a nearly constant low coating weight in the range of, for example, 1.0 to 3.5 g / m ² ,

In addition, the activating agent according to the invention may also preferably be added to a cleaning agent and used in a cleaning agent. This makes it possible to clean and activate in one step and saves at least one bath. This is particularly advantageous for simple production runs without very high quality requirements.

The metallic articles activated and phosphated by the process according to the invention and optionally also further coated may be used in particular in the automotive industry, the automotive supplier industry and the steel industry, as well as in the construction industry and in apparatus construction. The substrates coated by the process according to the invention can be used in particular as wire, wire mesh, tape, sheet metal, profile, cladding, part of a vehicle or missile, element for a household appliance, element in construction, frame, guard rail, radiator or fence element, Form part of complicated geometry or small part such as Screw, nut, flange or spring.

With the method according to the invention, it was possible to further improve the bath life, bath stability, crystal size, resistance at elevated use temperature and corrosion protection.

It was surprising that the duration of use of the activating agent could be increased in part by about a factor of 5 to 10, even without supplementing the activating agent, owing to the addition of a very small amount of at least one silicon compound.

It was also surprising that the thermal stability (= resistance at an operating temperature of the activating agent above 50 ° C) could be significantly improved.

Moreover, it was surprising that not only a stabilizing effect on the coating weight, but also an improving effect for the refining of the phosphate crystal sizes occurred in the long run, as the grain size level often looked at average crystal sizes in the range of 3 to 10 μm under the scanning electron microscope established.

Furthermore, it was surprising that the quality of the deposited phosphate layer did not deteriorate as a result of the introduction of the measures according to the invention, but could be maintained in consistent quality over the long term. Furthermore, the layer weight of the phosphate layer remained largely constant over the entire production period, because the coating weight fluctuations could even be in a laboratory experiment over 5 working days from originally +/- 0.1 to +/- 3.0 g / m ² in a conventional Aktivierungsmittelbad on + / 0.1 to +/- 1.0 g / m ² are lowered in an activating agent bath according to the invention.

Examples and Comparative Examples:

The object of the invention will be explained in more detail with reference to embodiments. The examples were carried out using the following substrates, process steps, substances and mixtures:

1. a) Die Substratoberflächen wurden in einer 2,5 %-igen Lösung eines alkalischen Reinigers über 10 Minuten bei 60 °C gereinigt und hierbei gründlich entfettet.
2. b) Es folgte eine Spülung mit Leitungswasser über 0,5 Minuten bei Raumtemperatur.
3. c) Dann wurden die Oberflächen durch Tauchen in ein kolloidales Titanphosphat enthaltendes Aktivierungsmittel über 0,5 Minuten bei Raumtemperatur aktiviert. Die Aktivierungsmittel werden in Tabelle 2 wiedergegeben. Die Aktivierungsmittel A wurden hergestellt durch Mischen, Versetzen mit Wasser und gegebenenfalls Kneten bei erhöhter Temperatur. Die Aktivierungsmittel B wurden aus dem Aktivierungsmittel A unter Zugabe von mehreren Zusätzen im festen Zustand und durch Mischen hergestellt. Die Aktivierungsmittel C wurden aus den Aktivierungsmitteln B durch Zugabe von Wasser, Stabilisierungsmittel(n), Silan und gegebenenfalls einem Additiv zur pH-Werteinstellung sowie durch Rühren hergestellt. Hierbei erfolgte ein Dispergieren und Auflösen in Wasser. Die Aktivierungsmittel D wurden aus den vermehrt Wasser enthaltenden Aktivierungsmitteln A, die zusätzlich bereits ein erstes Stabilisierungsmittel enthielten, durch Zugabe von Wasser, Stabilisierungsmittel(n), gegebenenfalls Silan und mindestens einem Zusatzstoff unter Rühren hergestellt. Die Aktivierungsmittel E wurden aus den Aktivierungsmitteln D durch Zugabe von Wasser, Stabilisierungsmittel und gegebenenfalls Silan sowie durch Rühren hergestellt. Es ergaben sich keine Unterschiede im Verhalten des Aktivierungsmittels E, wenn Silan bereits dem Aktivierungsmittel D oder erst dem Aktivierungsmittels E zugegeben wurde.
4. d) Danach wurden die Oberflächen über 3 Minuten bei 55 °C durch Tauchen in eine Phosphatierungslösung zinkphosphatiert. Die verwendeten Phosphatierungslösungen werden im Folgenden charakterisiert.
5. e) Anschließend wurde zuerst mit Leitungswasser und danach mit vollentsalztem Wasser gespült.
6. f) Dann wurden die beschichteten Substrate im Trockenofen bei 100 °C über 10 Minuten getrocknet.
7. g) Schließlich wurden die trockenen Prüfbleche mit einem kathodischen Tauchlack versehen und mit den weiteren Schichten eines in der Automobilindustrie für Karosserien üblichen Lackaufbaus beschichtet (Schichtaufbau und Lacke entsprechend Daimler AG in Mondsilber).

Die Zusammensetzung der jeweiligen Aktivierungsmittel bzw. die Ergebnisse der Prüfungen sind in den Tabellen 2 bzw. 3 aufgeführt.
Jedes Silan, das dem Aktivierungsmittel zugesetzt wurde, wurde vorher teilweise oder vollständig hydrolysiert oder/und kondensiert. Gegebenenfalls wurde hierbei der pH-Wert der wässerigen Lösung eingestellt.
Silan-Typen mit jeweils mindestens einer organischen Gruppe:

1. 1 Alkoxysilan A
2. 2 Alkoxysilan B
3. 3 Alkoxysilan C
4. 4 Alkoxysilan D
5. 5 Phenylsilan
6. 6 Bernsteinsäuresilan
7. 7 Triaminofunktionelles Silan
8. 8 Epoxysilan.

Als Stabilisierungsmittel sind in den Aktivierungsmitteln Pyrophosphat(e), Tripolyphosphat(e), Eindickungsmittel oder/und mindestens einer der Zusatzstoffe Nr. 9 bis 11 verwendet worden.
Zusatzstoff Nr.:

• 9 1-Hydroxyethylen(1,1-diphosphonsäure)
• 10 amorphe Kieselsäure
• 11 Carbonsäure-Copolymer.

Die Temperaturstabilität wird in den Tabellen so angegeben, dass die Werte des Schichtgewichtes der danach erzeugten Zinkphosphatschicht bei den Versuchen bei einer Aktivierungsmittelbadtemperatur von z.B. 40 °C den Wertebereich von 1,5 - 3 g/m² nicht überschritten haben, wobei die jeweilige Badstandzeit in die Bewertung einfloss. Das Schichtgewicht wurde mit einem Gardometer bestimmt.The test panels consisted of cold-rolled steel (CRS) with a thickness of 1.2 mm or on both sides galvanized steel with a coating of hot-dip galvanizing (HDG) or of an electrolytic galvanizing (EG) with a thickness of about 7 microns on each side. The area of the substrates measured over both surfaces was about 400 cm ² .

1. a) The substrate surfaces were cleaned in a 2.5% solution of an alkaline cleaner for 10 minutes at 60 ° C and thereby degreased thoroughly.
2. b) Rinsing with tap water followed for 0.5 minutes at room temperature.
3. c) Then the surfaces were activated by immersion in a colloidal titanium phosphate-containing activator for 0.5 minutes at room temperature. The activating agents are given in Table 2. The activating agents A were prepared by mixing, adding water and optionally kneading at elevated temperature. The activating agents B were prepared from the activating agent A with the addition of several additives in the solid state and by mixing. The activating agents C were prepared from the activating agents B by addition of water, stabilizing agent (s), silane and optionally a pH adjusting additive and by stirring. This was followed by dispersing and dissolving in water. The activating agents D were prepared from the increasingly water-containing activating agents A, which in addition already contained a first stabilizing agent, by adding water, stabilizing agent (s), optionally silane and at least one additive with stirring. The activating agents E were prepared from the activating agents D by adding water, stabilizing agent and optionally silane and by stirring. There were no differences in the behavior of the activating agent E when silane was already added to the activating agent D or first to the activating agent E.
4. d) Thereafter, the surfaces were zinc phosphated at 55 ° C for 3 minutes by immersion in a phosphating solution. The phosphating solutions used are characterized below.
5. e) It was then rinsed first with tap water and then with demineralized water.
6. f) Then the coated substrates were dried in a drying oven at 100 ° C for 10 minutes.
7. g) Finally, the dry test panels were provided with a cathodic dip and with the other layers of a in the automotive industry for bodies Coating usually coated (layer structure and paints according to Daimler AG in lunar silver).

The composition of the respective activating agents or the results of the tests are listed in Tables 2 and 3, respectively.
Any silane added to the activator has previously been partially or fully hydrolyzed or / and condensed. Optionally, the pH of the aqueous solution was adjusted in this case.
Silane types each having at least one organic group:

1. 1 alkoxysilane A
2. 2 alkoxysilane B
3. 3 alkoxysilane C
4. 4 alkoxysilane D
5. 5 phenylsilane
6. 6 succinic acid silane
7. 7 Triaminofunctional silane
8. 8 epoxysilane.

As the stabilizing agent, pyrophosphate (s), tripolyphosphate (s), thickening agent or / and at least one of additives Nos. 9 to 11 have been used in the activating agents.
Additive No .:

• 9 1-hydroxyethylene (1,1-diphosphonic acid)
• 10 amorphous silica
• 11 carboxylic acid copolymer.

The temperature stability is indicated in the tables in such a way that the values of the layer weight of the zinc phosphate layer produced afterward have not exceeded the value range of 1.5-3 g / m ² in the experiments at an activating-agent bath temperature of, for example, 40 ° C., the respective bathing life in the rating flowed. The coating weight was determined with a Gardometer.

In addition, it was determined radiographically on a sample of an activating agent A which hardly contained any water that primarily Na ₂ HPO ₄ , Na ₂ HPO ₄ .2H ₂ O and small amounts of TiOSO _{4 are} present as crystalline substances. Titanium phosphate could not be detected by powder diffractometry.

The average crystal size was roughly estimated when viewed under the Scanning Electron Microscope (SEM) or appropriately magnified SEM images.

The inventive examples B 1 to B 9 and B 16 to B 27 and the comparative examples VB 10 to VB 15 relate to so-called powder activations and B 28 to B 31 so-called liquid activations. For the phosphate coating experiments, phosphating solutions I to V were used in diving. In addition to nitrate, they mainly contained nitrite, nitroguanidine or hydrogen peroxide as accelerators. As cations, in addition to alkali metal ions, iron ions, and cations leached from metallic surfaces, they essentially contained only zinc, manganese, and nickel as in typical low-zinc phosphating solutions. As anions, they partially contained silicon hexafluoride and small amounts of free fluoride. The application of the phosphating I to V was carried out by dipping. Their free acid FS values ranged from 1.4 to 1.7, their total acid GS values ranged from 22 to 28, their total acid Fischer GSF values ranged from 15 to 20, and their S Values as the ratio of FS to GSF were approximately in the range of 0.07 to 0.10. Layer weight was determined gravimetrically by weighing before and after peeling the phosphate layer, peeling on aluminum alloys with nitric acid, on steel and zinc rich surfaces with ammonium dichromate solution. The various phosphating agents all looked similar and similarly good, but the crystal forms and crystal sizes of the phosphate crystals varied significantly. There were always good or even very good phosphate coatings. Table 3: Coatings and test results on coatings using the phosphating solutions on activating and phosphating for 5 days each B 1 B 2 B 3 B 4 B 5 B 6 B 7 B 8 B 9 Type of sheets CRS CRS CRS CRS CRS CRS CRS CRS CRS Activation type C C C C C C C C C Activating agent no. 17 1 2 3 4 8th 11 12 13 Coating weight g / m ² beginning 1.7 1.7 1.5 1.5 1.5 1.8 1.6 1.3 1.7 Coating weight g / m ² end 2.0 2.0 1.8 1.5 1.6 2 1.5 1.7 1.7 Degree of coverage visually in% 100 100 100 100 100 100 100 100 100 Appearance gleichmäß. equally. gleichmäß. gleichmäß. equally. equally. equally. equally. equally. Avg. Crystal size μm beginning <5 5 5 5 5 5 5 <5 5 Average crystal size μm end <5 5 5 5 5 5 - 10 5 <5 5 Corrosion Test: Salt spray test DIN EN ISO 9227 over 1008 h U <1 - U <1 U <1 - - - - U <1 VDA climate change test VDA 621-415 over 10 laps 1.7 - 1.5 1 - - - - 1.9 CASS test DIN EN ISO 9227 CASS <1 - <1 <1 - - - - <1 Filiform test DIN EN 3665 0.6 - 0.8 - 0.5 - 0.7 0.3 - 0.5 - - - - 0.9-1.3 1.8 - 3.2 3,0 - 4,5 2.8 - 3.8 2.5-3.8 Rockfall according to DIN EN ISO 20567-1 n. 10 rounds VDA 1.5 - 1.5 2 - - - - 1.5 Paint adhesion tests: Cross-cut according to BMW GS 90011 1 - 1 1 - - - - 1 VB 10 VB 11 VB 12 VB 13 VB 14 VB 15 B 16 B 17 B 18 Type of sheets CRS CRS CRS CRS CRS CRS CRS CRS CRS Activator type C C C C C C C C C Activating agent no. 1 1 1 1 1 1 1 1 1 Coating weight g / m ² beginning 2.5 3.5 4.1 4.4 2.5 5.3 2.5 5 3 Coating weight g / m ² end 5.5 > 5.5 > 7 > 7 3 > 7 3.8 5 4.4 Degree of coverage visually 100 80 70 80 100 70 100 70 100 Appearance evenly - - - evenly - evenly - evenly Avg. Crystal size μm beginning 5 15 25 25 5 - 10 25 15 60 20 Average crystal size μm end 60 40 > 60 > 60 10 - 15 > 60 20 60 25 - 30 B 19 B 20 B 21 B 22 B 23 B 24 B 25 B 26 B 27 Type of sheets CRS CRS CRS CRS CRS CRS CRS CRS CRS Activator type C C C C C C C C C Activating agent no. 1 1 8th 9 11 12 13 13a 13 Coating weight g / m ² beginning 2.2 2.1 2 3 1.8 2.0 1.4 1.4 1.7 Coating weight g / m ² end 1.8 1.6 3.1 4.7 1.7 2.2 4.5 4.4 1.6 Degree of coverage visually% 100 100 100 100 100 100 100 100 100 Appearance evenly evenly evenly evenly evenly evenly evenly evenly evenly Avg. Crystal size μm beginning 5 5 5 10 - 15 <5 <5 <5 <5 <5 Average crystal size μm end 5 5 10 - 20 25 5 <10 20 25 <5 Corrosion Test: Salt spray test DIN EN ISO 9227 over 1008 h - - - U <1 - - - - U <1 VDA climate change test VDA 621-415 over 10 laps - - - 1.5 - - - - 1.5 CASS test DIN EN ISO 9227 CASS - - - <1 - - - - <1 Filiform test DIN EN 3665 - - - 0.4-0.5 - - - - 0.9-1.3 2.6-3.9 2.6 to 4.1 Rockfall according to DIN EN ISO 20567-1 n. 10 rounds VDA - - - 1.5 - - - - 1.5 Paint adhesion tests: Cross-cut according to BMW GS 90011 - - - 1 - - - - 1 B 28 B29 B30 B 31 VB 1 VB 2 Type of sheets CRS CRS CRS CRS CRS CRS Activator type e e e e C e Activating agent no. 14 15 16 17 1 17 Coating weight g / m ² beginning 2.8 2.1 2.2 1.7 2.2 2.5 Coating weight g / m ² end 3.5 2.5 2.4 2.0 4.8 4.2 Degree of coverage visually 100 100 100 100 100 100 Appearance evenly evenly evenly evenly evenly evenly Avg. Crystal size μm beginning 10 <5 <5 <5 5 10 Average crystal size μm end 15 - 25 5 5 <5 50 30 Corrosion Test: Salt spray test DIN EN ISO 9227 over 1008 h - - - U <1 U <1 - VDA climate change test VDA 621-415 over 10 laps - - - 1.7 1.8 - CASS test DIN EN ISO 9227 CASS - - - <1 <1 - Filiform test DIN EN 3665 - - - 0.9-1.5 0.3-0.4 - 2.8 to 4.1 2.8 - 3.5 Rockfall according to DIN EN ISO 20567-1 n. 10 rounds VDA - - - 1.5 2 - Paint adhesion tests: Cross-cut according to BMW GS 90011 - - - 1 1 -

The smaller the values for the corrosion and paint adhesion tests, the better the results. It was found in these experiments that the corrosion results and the paint adhesion results were partly a little better, but never worse, if instead of activation according to the prior art, the activation according to the invention was used.

The zinc phosphate crystal sizes were in the inventive examples partially slightly smaller or even significantly smaller than in the comparative examples.

Claims (19)

1. A method for phosphating metallic surfaces, for which the metallic surfaces prior to phosphating are treated with an aqueous colloidal activating agent based on phosphate and titanium, wherein the activating agent comprises at least one water-soluble silicon compound having at least one organic group, selected from bis(3-trimethoxysilylpropyl)amine and bis(3-triethoxysilylpropyl)amine, more particularly as hydrolyzed and/or condensed silane/silanol/- siloxane/polysiloxane, the total content of the water-soluble silicon compounds having at least one organic group in the activating agent being in the range from 0.0001 to 0.2 g/L, calculated in each case as silane and/or as corresponding principally present silicon-containing starting compound, and where the aqueous colloidal activating agent is prepared from an aqueous colloidal activating agent (precursor A) by way of a pulverulent activating agent (precursor B) and thereafter, before application to the metallic surfaces, is dissolved in water and dispersed (activating agent C), or is prepared from an aqueous colloidal activating agent (precursor A) by way of an aqueous colloidal activating agent (precursor D) and thereafter, before application to the metallic surfaces, is diluted in water (activating agent E).
2. The method according to claim 1, wherein at least one substance such as, for example, in each case at least one biocide, surfactant, stabilizer and/or additive for pH adjustment is added particularly when dissolving and dispersing or when diluting.
3. The method according to either of the preceding claims, wherein the aqueous colloidal activating agent comprises titanium phosphate, orthophosphate, alkali metal, and optionally at least one stabilizer and/or a further adjuvant.
4. The method according to any of the preceding claims, wherein the titanium content of the aqueous activating agent is in the range from 0.0001 to 10 g/L.
5. The method according to any of the preceding claims, wherein the phosphate content, calculated as PO₄, of the aqueous activating agent is in the range from 0.005 to 300 g/L.
6. The method according to any of the preceding claims, wherein the phosphate is present in the aqueous colloidal activating agent in the form of titanium phosphate, titanyl phosphate, disodium phosphate and/or dipotassium phosphate.
7. The method according to any of the preceding claims, wherein the total cobalt, copper and/or nickel content of the aqueous activating agent is in the range from 0.00001 to 0.1 g/L.
8. The method according to any of the preceding claims, wherein the activating agent comprises in each case at least one anionically modified polysaccharide, water-soluble organic copolymer, carboxylic acid, phosphonic acid, diphosphonic acid, triphosphonic acid, polyphosphonic acid, polyelectrolyte and/or derivatives thereof.
9. The method according to any of the preceding claims, wherein the activating agent also includes a cleaning-agent mixture, at least one surfactant and/or at least one hydrotrope.
10. The method according to any of the preceding claims, wherein the activating agent also includes in each case at least one biocide, wetting agent, softener, complexing agent, sequestrant and/or marker.
11. The method according to any of the preceding claims, wherein the activating agent is a colloidal solution or colloidal dispersion or a pulverulent activating agent, the latter being dissolved and dispersed for use in a coating method.
12. The method according to any of the preceding claims, wherein the activating agent is applied at a temperature in the range from 10 to 80°C to the metallic surfaces.
13. The method according to any of the preceding claims, wherein the activating agent is applied by flooding, flow coating, spraying, dipping and/or rolling and optionally squeezing-off to the metallic surfaces.
14. The method according to any of the preceding claims, wherein the metallic surfaces before activation are cleaned, degreased and/or pickled and/or after activation and before phosphating are rinsed with water.
15. The method according to any of the preceding claims, wherein the metallic surfaces after activation are phosphated, rerinsed and/or provided with at least one organic coating.
16. An aqueous colloidal activating agent based on titanium phosphate and on at least one further phosphate not containing titanium, for treating metallic surfaces prior to phosphating, wherein the activating agent comprises at least one water-soluble silicon compound having at least one organic group, selected from bis(3-trimethoxysilylpropyl)-amine and bis(3-triethoxysilylpropyl)amine, more particularly as hydrolyzed and/or condensed silane/silanol/siloxane/polysiloxane, the total content of the water-soluble silicon compounds having at least one organic group in the activating agent being in the range from 0.0001 to 0.2 g/L, calculated in each case as silane and/or as corresponding principally present silicon-containing starting compound.
17. The aqueous colloidal activating agent according to claim 16, which is an aqueous colloidal activating agent C, prepared from an aqueous colloidal activating agent A by way of a pulverulent activating agent B and for which the pulverulent activating agent B has then been dissolved and dispersed in water for application, or is an aqueous colloidal activating agent E, which has been prepared from an aqueous colloidal activating agent A by way of an aqueous colloidal activating agent D and for which the aqueous activating agent E has been prepared by dilution with water, where the term "colloidal" refers only to titanium phosphate colloids.
18. The use of an activating agent according to either of claims 16 and 17 in a cleaning composition.
19. The use of the substrates coated by the method according to any of claims 1 to 15 as wire, wire mesh, strip, panel, profile, cladding, part of a vehicle or aircraft, element for a household appliance, element in construction, frame, guardrail element, radiator element or fence element, shaped part of complex geometry, or small part.