EP3031951B1 - Optimized process control in the pretreatment of metals to protect against corrosion on the basis of baths containing fluoride - Google Patents

Description

The present invention relates to a method for anticorrosive treatment, comprising a series of components with metallic surfaces of iron and / or zinc with a passivated aqueous pretreatment solution in a system tank containing compounds of zirconium and / or titanium and a source of fluoride ions in Contact is brought. In the process according to the invention, part of this pretreatment solution is discarded and replaced by a total of at least equal volume of one or more such supplemental solutions by metering into the system tank of the pretreatment. While the Verwurf must not fall below a predetermined value depending on the molar ratio of fluoride ions to the content of zirconium and / or titanium, even in a complete abandonment of the use of chemicals to regulate the pickling rate or stabilize the ionic freight, a permanently satisfactory corrosion protection treatment To ensure the addition of supplementary solution is done in such a way that a maintenance of the concentration of the elements zirconium and / or titanium is ensured in the passivating aqueous pretreatment solution in the form of water-soluble compounds.

Modern production lines in which a pretreatment for anti-corrosive coating before applying a paint is demanded not only a high production rate associated with a high material consumption per unit time, but also a high flexibility in terms of the components to be treated in conjunction with variations in the chemical consumption and the Type of load of the baths used for this purpose. Thus, it is not uncommon and common practice in the automotive supply industry to use one and the same pre-treatment bath for the serial coating of different components with different surface portions of different metallic materials. On the other hand, in painting lines of production lines of the automobile industry usually identical bodies at belt speeds of 3 - 6 m / min immersed in pass tanks containing 150 - 450 m ^{3 of} the pretreatment solution and pretreated in this way in series, so that up to 80 bodies, each with about 100 pretreated m ² metallic surface per hour.

A continuous, precise monitoring of the pretreatment processes is fundamentally crucial for the optimum dosing of the active components and possibly regulating chemicals in the surface treatment of metallic surfaces of components. This effort can only in modern production lines by a largely Automated monitoring and control of process chemicals dosing to maintain a long-lasting, optimal ratio of chemicals in process baths to meet the principles of material efficiency and consistent pre-treatment quality.

In particular, the passivating pretreatment of metallic components based on acidic aqueous pretreatment solutions of fluorometallates of the elements zirconium and / or titanium as an alternative to the chromating process, which is becoming increasingly less popular because of the toxic properties of chromium (VI) compounds, has long been known and established , As a rule, such pretreatment solutions contain additional active components which are intended to further improve the anticorrosive action and paint adhesion. Exemplary here is the EP 1 571 237 which discloses a pretreatment solution suitable for various metal surfaces containing up to 5000 ppm zirconium and / or titanium and up to 100 ppm free fluoride. In addition, the solution may contain further components selected from chlorate, bromate, nitrite, nitrate, permanganate, vanadate, hydrogen peroxide, tungstate, molybdate or in each case the associated acids. Organic polymers may also be present. After treatment with such a solution, the metal surfaces can be rinsed with another passivating solution.

A pretreatment bath for producing a passivating conversion layer on metal surfaces therefore requires in individual cases a large number of active components which have to be regularly replenished during operation of a pretreatment bath. In order to maximize material efficiency, there is a continuing need to make the pretreatment processes more resource efficient, i. operate under conditions in which the use of active components can be reduced.

The DE 10 2008 038653 discloses in this context a method in which the entrained with the component in the sink active components of a pre-treatment in the rinse water before the actual pretreatment to produce a zirconium and / or titanium-based conversion layer are cascaded back. In this pre-rinse, the proportion of cascaded active components causes a partial passivation, which is completed in the subsequent pretreatment. In this way, it is already possible to reduce the actual amount of active components used per component to be treated and thus to increase the material efficiency.

Notwithstanding these advances in material efficiency, the maintenance effort of a pre-treatment bath during operation remains enormous, since the amount of active components in a control window dictated by the type of pre-treatment must, of course, be constantly maintained.

In addition, during operation of a pretreatment bath, an accumulation of components dissolved in water takes place, which are either pickled out of the metal surfaces of the treated components, represent reactants of the active components or are introduced from upstream treatment steps, such as a wet chemical cleaning step, into the pretreatment bath. Therefore, depending on the material properties of the components to be treated, the type of pretreatment and the preceding treatment steps and the procedural process management, a pretreatment bath aims at a steady state equilibrium, sometimes aiming at equilibrium concentrations for certain components, which have a detrimental effect on the result of the pretreatment can. So it is not enough to track only active components. Rather, the use of regulating chemicals is often necessary to prevent the quality of the pre-treatment during operation from deteriorating.

So reported the DE 10 2008 014465 with regard to the corrosion protection treatment of metallic components by means of pretreatment solutions of fluorometallates of the elements zirconium and / or titanium, it is crucial to maintain an optimum molar ratio of fluoride ions to elements of the elements zirconium and / or titanium during serial pretreatment, ie during operation. Furthermore, it is proposed there for a consistently good quality of the anticorrosive pretreatment to meter certain amounts of fluoride scavengers to the pretreatment. Accordingly, the fluoride scavengers are regulatory chemicals and in the specific case are preferably selected from compounds which release aluminum ions, calcium ions and / or iron ions. In this context, it is again found there that too high a relative proportion of aluminum ions in the pretreatment bath inhibits the titanium- and / or zirconium-based conversion layer formation, in particular on the steel surfaces of the components, so that lower layer coverings and thus insufficient corrosion protection tend to result.

VW:  Verwurf an Vorbehandlungslösung in L/m²;
${\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}:$

  Konzentration an Zirconium und/oder Titan in der Vorbehandlungslösung in mmol/L;
Z_E:  molare Verhältnis der Gesamtmenge an Fluor zur Gesamtmenge der Elemente Zirconium und/oder Titan im hinzudosierten Gesamtvolumen der Ergänzungslösungen mit der Maßgabe, dass folgendes gilt: $${\mathrm{z}}_{\mathrm{E}}<\frac{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}}+\mathrm{6}$$

Each addition of a fluoride scavenger as a regulatory chemical to maintain the performance of the pretreatment must therefore result in accurately predictable concentrations of the active components in the pretreatment bath, otherwise it can not be guaranteed that the serial pretreatment of components takes place under optimal process conditions, namely in compliance with the empirically found material parameter limits. In addition, there is the difficulty of directly measuring the amount of total fluoride or free fluoride, since the conventional methods are based on the determination by means of ion-selective electrodes and thus on slowly adjusting chemical equilibria. The derivation of the actual size for setting the target size by means of fluoride scavenger is thus subject to a temporal blur, which may be depending on the manufacturing process in the order of the treatment time of the metallic component. A consistent quality of the serial anticorrosive pretreatment by means of acidic aqueous pretreatment solutions of fluorometalates of the elements zirconium and / or titanium can therefore only be ensured with a high level of analytical and process engineering effort, and last but not least, the use of considerable quantities of regulating chemicals. The WO 2013/126632 discloses supplementary solutions for conversion solutions containing Zr. The supplement solution contains fluorine-containing and fluorine-free zirconium compounds. Part of the spent conversion solution is discarded. The object of the present invention is thus, in the serial corrosion-protective treatment of metallic surfaces having components by means of acidic aqueous pretreatment solutions of water-soluble compounds of the elements zirconium and / or titanium considerably simplify the process engineering effort to monitor and control the process-relevant bath parameters and at the same time Significantly increase material efficiency with regard to the use of regulating bath chemicals. A further object was to optimize the process so that a reliable corrosion-protective conversion based on the zirconium and / or titanium elements takes place, in particular, on the iron surfaces of the components treated in series, which are then used in conjunction with an organic primer coating or an organic primer coating Dipping paint meets the high requirements for permanent corrosion protection.
This object is achieved by a method for anticorrosive treatment of a plurality of metallic surfaces of zinc and / or iron-containing components in series, in which each of these components with a present in a system tank passivating aqueous pretreatment solution at a temperature of less than 50 ° C in contact wherein the passivating aqueous pretreatment solution contains and is in contact with one or more water-soluble compounds of the elements zirconium and / or titanium and one or more water-soluble compounds which are a source of fluoride ions, and is contacted for such time; that on the metallic surfaces of zinc and / or iron, a coating layer of at least 0.1 mmol / m ² based on the elements zirconium and / or titanium results, but none of these metallic surfaces relative a layer circulation of more than 0.7 mmol / m ² to the elements zirconium and / or comprises titanium, and wherein during the anti-corrosion treatment of the components in series discarded part of the passivating aqueous pretreatment solution of the system tank and in total at least by a equivalent volume of one or more supplemental solutions is replaced by metering into the system tank in such a way that maintaining the concentration zirconium and / or titanium in the passivating aqueous pretreatment solution in the form of water-soluble compounds results, further characterized in that a concentration of the elements Zirconium and / or titanium in the passivating aqueous pretreatment solution in the form of water-soluble compounds of at least 0.05 mmol / L but less than 0.8 mmol / L in total is maintained in the system tank, and the molar ratio of the total amount of fluorine i n form of water-soluble compounds which are a source of fluoride ions (hereinafter "total amount of fluorine"), to the total amount of elements zirconium and / or titanium in the form of water-soluble compounds (hereinafter "total amount of elements zirconium and / or titanium") in the added total volume of the replenisher is less than the same ratio in the passivating aqueous pretreatment solution but not smaller than 4.5, and the amount of passivating aqueous pretreatment solution in liters per per square meter of metallic surfaces of zinc and iron is at least the following value ie greater than or equal to the following value: $$\mathrm{VW}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot {\mathrm{10}}^{-\mathrm{1}}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}$$

VW: throw on pretreatment solution in L / m ² ;
${\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}:$

Concentration of zirconium and / or titanium in the pretreatment solution in mmol / L;
Z _E : molar ratio of the total amount of fluorine to the total amount of the elements zirconium and / or titanium in the added total volume of the replenisher with the proviso that $${\mathrm{z}}_{\mathrm{e}}<\frac{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}}+\mathrm{6}$$

The method according to the invention has the effect that, via the regulated throw, the free fluoride portion in the pretreatment solution does not exceed values for which a structural change of the conversion layer already occurs, which is regularly accompanied by a worsening of the anticorrosive properties and the paint adhesion.

besonders bevorzugt zumindest folgenden Wert an: $$\mathrm{VW}=\frac{7\cdot \left({\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}\right)}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot {\mathrm{10}}^{-\mathrm{1}}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}$$

In a preferred embodiment of the method according to the invention, the throw of pretreatment solution for achieving the same purpose takes at least the following value: $$\mathrm{VW}=\frac{\mathrm{3}\cdot \left({\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}\right)}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot {\mathrm{10}}^{-\mathrm{1}}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}.$$

particularly preferably at least the following value: $$\mathrm{VW}=\frac{7\cdot \left({\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}\right)}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot {\mathrm{10}}^{-\mathrm{1}}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}$$

According to the invention, the throw is the liquid volume of pretreatment solution normalized to the unit surface (1 m ² ) of the components to be treated which leaves the system tank during the serial pretreatment by passive extraction or due to a continuous or discontinuous overflow per square meter of a treated component.

A pre-treatment in series according to the present invention is when a plurality of components is brought into contact with the pre-treatment solution in the system tank, whereby the individual components are brought into contact one after the other and thus separated in time. The system tank is the container in which the pretreatment solution is in series for the purpose of passivating pretreatment.

The area to be set in the method according to the invention for the layer coating based on the elements Zr and / or Ti can be coated by means of X-ray fluorescence analysis (RFA) after calibration using solutions of known molarity of H ₂ ZrF ₆ and H ₂ TiF ₆ in the dry-in-place method Metal surfaces are determined. The solutions of known molarity are applied to produce the calibration sample plates in a defined wet film thickness and the wet film is then completely dried. The determination of the actual layer support according to the present invention can be based on these Kalibrierprobebleche both after drying the pretreated and rinsed surfaces of the components or after pretreatment and the first sink, for example, after rinsing a body immediately after the pretreatment in passing a so-called Nasshalteringes in the rinse water by several Spray valves are applied to the body.

For the purposes of the present invention, compounds are "water-soluble" if their solubility in deionized water having a conductivity of not more than 1 μScm ^-1 at a temperature of 20 ° C. is at least 1 g / l.

oder alternativ kleiner als 9,25 ist, so dass der notwendige Verwurf an Vorbehandlungslösung eine solche obere Grenze aufweist, bei der die erfindungsgemäßen Verfahren im Wesentlichen für alle umfassten Vorbehandlungslösungen noch wirtschaftlich sinnvoll betrieben werden können.As can be seen from the solution of the problem, the maintenance of the concentration of the elements zirconium and / or titanium can be carried out by adding one or more supplementary solutions into the system tank. In the added total volume of the replenisher or replenishers, the molar ratio of the total amount of fluorine in the form of compounds dissolved in water to the total amount of zirconium and / or titanium in the form of compounds dissolved in water should not be less than 4.5. Below this value, the dosage of a required amount of zirconium and / or titanium compounds dissolved in water may not be practicable since the compounds tend to form colloidal solutions and hence poorly soluble precipitates, thus providing one of the maintenance of the active components in the pretreatment solution Dosing such supplement solution can hardly be done reliably. In a preferred embodiment of the method according to the invention, therefore, the molar ratio of the total amount of fluorine to the total amount of zirconium and / or titanium in the added total volume of replenishers is not less than 5.0, more preferably not less than 5.5. Conversely, it is preferred that the same ratio in the added total volume of the supplemental solutions in the inventive method is less than $\frac{\mathrm{0}.\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}}+\mathrm{6}$

or alternatively is less than 9,25, so that the necessary Verwurf at pretreatment solution has such an upper limit, in which the inventive method can be operated economically useful for substantially all pre-treatment solutions included.

In the following, for the purpose of linguistic simplification, reference will be made only to a supplementary solution, and the case will nevertheless be encompassed in that several identical or differently composed supplementary solutions are added to the system tank to compensate for the throwing and to maintain the concentration of zirconium and / or titanium. Thus, if reference is made below to a supplementary solution, and more specifically to an extensive or specific characteristic thereof, then the sum of all added supplementary solutions is always included and the resulting averaged extensive or specific characteristics in summary.

The inventive method makes due to the controlled Verwurfes bath solution and the consequent replenishment of supplementary solution that the enrichment of free fluoride in the pretreatment solution is limited so that an adverse effect on the conversion coating based on the elements zirconium and / or titanium omitted. It should also be emphasized that the inventive method addition of fluoride scavengers - compounds which bind and thus reduce their concentration of free fluorides - makes superfluous, since the free fluoride concentration is completely controlled by the throw of bath solution. The minimum throw is for the given conditions with respect to the concentration of active components in the pretreatment solution and the planned coating layer of a maximum of 0.7 mmol / m ² based on the elements zirconium and titanium according to the semi-empirically found term (1) or the preferred semi These terms for the minimum throw are only based on the specific concentration of zirconium and / or titanium in the pretreatment solution and the ratio of the elements fluorine in the form of compounds dissolved in water to the total amount Accordingly, in order to maintain optimum process conditions in the pretreatment, only the determination of the concentration of the active components in the form of the elements zirconium and / or titanium, which in any case is sufficient, is required Conversion layer training regularly z u is controlling. The monitoring of the amount of free fluoride in the pretreatment solution becomes unnecessary in the process according to the invention.

Since, as already mentioned, the metered addition of fluoride scavengers to the pretreatment solution can be dispensed with, its proportion in the addition volume added according to the invention to the replenisher solution is low for reasons of material efficiency. Accordingly, processes according to the invention are preferably processes for which the molar ratio of the total amount of the elements zirconium and / or titanium in each case to the total amount of one of the elements calcium, magnesium, aluminum, boron, iron, manganese or tungsten in the form of water-soluble compounds in the added total volume of the supplementary solution is greater is 5: 1, more preferably greater than 10: 1.

A further advantage of the method according to the invention is that sufficient coating deposits of zirconium and / or titanium are already achieved with relatively low concentrations of active components for corrosion protection and adhesion to a subsequently applied organic primer. In this context, those methods according to the invention are preferred for material efficiency in which the passivating aqueous pretreatment solution in the system tank is less than 0.65 mmol / L, more preferably less than 0.55 mmol / L, most preferably less than 0.325 mmol / L of water-soluble compounds of the elements zirconium and / or titanium. A low concentration of active components also causes the stationary by being carried over into a downstream sink introduced proportion of these compounds is low. This is also regularly advantageous, since an additional contact time of the components with compositions containing active components often leads to a deterioration of the anti-corrosion properties, so that the sink is usually kept largely free of entrained fractions from the system tank of the pretreatment. In the preferred embodiments of the method according to the invention, this is not necessary or it may be on special measures to reduce the proportions of active components in the system tank of the sink, for example, the setting of an increased overflow - ie Verwurfes to rinse solution - be dispensed with.

VW:  Verwurf an Vorbehandlungslösung in L/m²;
${\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}:$

  Konzentration an Zirconium und/oder Titan in der Vorbehandlungslösung in mmol/L;
Z_E:  molares Verhältnis der Gesamtmenge an Fluor zur Gesamtmenge der Elemente Zirconium und/oder Titan im hinzudosierten Gesamtvolumen der ErgänzungslösungenFor a particularly economical method according to the invention and for ensuring that a sufficient amount of free fluoride is contained in the pretreatment solution of the system tank for conversion layer formation to be carried out under conventional process conditions, it is preferred that the rejection of passivating aqueous pretreatment solution is not greater than the following value in liters per per square meter treated metallic component is: $$\mathrm{VW}=\frac{7\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}\right)}{0.4\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot {\mathrm{10}}^{-\mathrm{1}}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}$$

VW: throw on pretreatment solution in L / m ² ;
${\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}:$

Concentration of zirconium and / or titanium in the pretreatment solution in mmol / L;
Z _E : molar ratio of the total amount of fluorine to the total amount of the elements zirconium and / or titanium in the added total volume of the supplementary solutions

Furthermore, it is advantageous for good stability and conversion of the metallic surfaces of the components if the pH of the passivating aqueous pretreatment solution in a preferred process according to the invention is not less than 3.0, more preferably not less than 3.5, but preferably not greater than 5.0, more preferably not greater than 4.5.

The "pH value" according to the present invention corresponds to the negative logarithm of the hydronium ion activity at 20 ° C. and can be determined by means of a pH-sensitive glass electrode.

The inventive method is preferably carried out at relatively low temperatures, so that evaporation losses in the system tank of Pretreatment solution can be neglected. Accordingly, in a preferred process of the invention, the temperature of the passivating aqueous pretreatment solution is not greater than 45 ° C, more preferably not greater than 40 ° C, most preferably not greater than 35 ° C.

The Verwurf provided in pretreatment solution according to the invention can be carried out during the corrosion protection treatment of the plurality of components process-related only quasi-continuous or discontinuous. The inventive process of the series treatment requires that with each treated component a certain amount of pretreatment solution irrevocably leaves the system tank. The amount of rejects entrained with each treated component is inherently discrete and therefore discontinuous and dependent on the specific treatment conditions and the geometry of the components. Furthermore, the dragged portion of Verwurf is only partially accessible to a control, for example by rotation or tilting of the components when immersed in the pretreatment solution or blowing off the components when lifting out the components from the system tank of the pretreatment. However, such procedural measures are complex and usually justified by no special added value. However, in the prior art, the processes are generally operated so that the components do not discharge properly pretreatment solution and usually be towed less than 50 ml per square meter of treated surface. If, in the following, therefore, a quasicontinuous or discontinuous throwing is used, only the actively dispensed volume of pretreatment solution is addressed and it has to be taken into account that the passively removed portion of the reject is always discarded discontinuously with each treated component.

Therefore, according to the invention, the rejection of passivating aqueous pretreatment solution is preferably carried out both by extracting pretreatment solution with each component of the series of components to be treated and by actively discharging pretreatment solution in each case from the system tank of the pretreatment.

For a discontinuous throw, the volume of pretreatment solution to be actively sprayed may be adjusted to the zirconium and / or titanium layer deposited on the components in the pretreatment step to provide as much as required for a coating of zirconium and / or titanium to be achieved. but not more than necessary to feed pretreatment solution and proceed as economically as possible in this way.

VW_d :  diskontinuierlicher Verwurf in Liter;
${\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}:$

  Verwurf durch Ausschleppung durch n Bauteile in Liter mit der Maßgabe das folgendes gilt: $${\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}\le \frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot {\displaystyle \sum _{\mathrm{i}}^{\mathrm{n}}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}};$$

${\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}:$

Anteil von Zinkoberflächen bezogen auf die Gesamtoberfläche von Zink und Eisen des i-ten in Serie behandelten Bauteils;
${\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}:$

Anteil von Eisenoberflächen bezogen auf die Gesamtoberfläche von Zink und Eisen des i-ten in Serie behandelten Bauteils;
${\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}:$

Schichtauflage in mmol/m² bezogen auf die Elemente Zirconium und/oder Titan auf den korrosionsschützend vorbehandelten Zinkoberflächen des i-ten in Serie behandelten Bauteils; und
${\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}:$

Schichtauflage in mmol/m² bezogen auf die Elemente Zirconium und/oder Titan auf den korrosionsschützend vorbehandelten Eisenoberflächen des i-ten in Serie behandelten Bauteils;
A_i: Gesamtfläche der metallischen Oberflächen von Zink und Eisen des i-ten in Serie behandelten Bauteils; und
n: positive natürliche Zahl {n ∈ N | n ≥ 1}In discontinuous operation, such processes are preferred in which the discontinuous Verwurf VW _{d is performed} on passivating aqueous pretreatment solution after pretreatment of a certain number n of components i, wherein the discontinuous Verwurf at least the following value in liters for a series treated number n of components i assumes: $${\mathrm{VW}}_{\mathrm{d}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot {\displaystyle \underset{\mathrm{i}}{\overset{\mathrm{n}}{\Sigma }}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}}-{\mathrm{VM}}_{\mathrm{a}}^{\mathrm{n}}$$

VW _d : discontinuous throw in liters;
${\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}:$

Cast by extraction by n components in liters with the proviso that: $${\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}\le \frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot {\displaystyle \underset{\mathrm{i}}{\overset{\mathrm{n}}{\Sigma }}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}};$$

${\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}:$

Proportion of zinc surface area relative to the total surface area of zinc and iron of the i-th series-treated component;
${\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}:$

Percentage of iron surface area relative to the total surface area of zinc and iron of the i-th series-treated component;
${\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}:$

Coating layer in mmol / m ² based on the elements zirconium and / or titanium on the corrosion-protective pretreated zinc surfaces of the i-th in series-treated component; and
${\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}:$

Coating layer in mmol / m ² based on the elements zirconium and / or titanium on the anticorrosion pretreated iron surfaces of the ith component treated in series;
A _i : total area of the metallic surfaces of zinc and iron of the ith series-treated component; and
n: positive natural number {n ∈ N | n ≥ 1}

As a preferred upper limit for the discontinuously fed pretreatment solution, processes according to the invention are preferred in which the discontinuous throw in liters for a number n of components i treated in series is the value $${\mathrm{VW}}_{\mathrm{d}}\le \frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{0.4\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot {\displaystyle \underset{\mathrm{i}}{\overset{\mathrm{n}}{\Sigma }}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}}-{\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}$$

does not exceed, wherein for the molar ratio of the total amount of fluorine to the total amount of the elements zirconium and / or titanium in the supplementary solution the following condition is satisfied: $${\mathrm{z}}_{\mathrm{e}}<\frac{\mathrm{0}.\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}}+\mathrm{6th}$$

Of course, the Verwurf to be set according to the invention can also be made quasi-continuous. For this mode of operation, it is preferable that the throwing by active feeding of passivating aqueous pretreatment solution and the replacement of discarded pretreatment solution with replenisher are carried out continuously during the pre-treatment of the components in series, more preferably by feeding a constant volume flow of replenishing replacer solution into the system tank of the pretreatment, wherein the continuous Verwurf at passivating aqueous pretreatment solution is preferably realized mainly by overflowing an open system tank.

"Predominantly" in this context means that more than 50%, preferably more than 80%, of the control accessible portion of the discarded pretreatment solution is not the inevitable part due to the scavenging effect of the components or the wet film adhered to the components owned by the Verwurfes, is removed by an overflow from the system tank. The overflow thus represents a particularly preferred type of Verwurfes by active feeding. Alternatively, the continuous Verwurf can also be realized by feeding a constant volume flow from the system tank.

VW_C :

kontinuierlicher Verwurf in Liter;

VW _a :

gemittelter Verwurf durch Ausschleppung in Liter mit der Maßgabe das folgendes gilt: $${\overline{\mathrm{VW}}}_{\mathrm{a}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot \left({\bar{\mathrm{x}}}^{\mathrm{Zn}}\cdot {\bar{\mathrm{S}}}^{\mathrm{Zn}}+{\bar{\mathrm{x}}}^{\mathrm{Fe}}\cdot {\bar{\mathrm{S}}}^{\mathrm{Fe}}\right)\cdot \bar{\mathrm{A}};$$

x ^Zn:

gemittelter Anteil von Zinkoberflächen bezogen auf die Gesamtoberflächen von Zink und Eisen einer Serie von behandelten Bauteilen;

x ^Fe:

gemittelter Anteil von Eisenoberflächen bezogen auf die Gesamtoberflächen von Zink und Eisen einer Serie von behandelten Bauteilen;

S ^Zn:

gemittelte Schichtauflage in mmol/m² bezogen auf die Elemente Zirconium und/oder Titan auf den korrosionsschützend vorbehandelten Zinkoberflächen der in Serie behandelten Bauteile; und

S ^Fe:

gemittelte Schichtauflage in mmol/m² bezogen auf die Elemente Zirconium und/oder Titan auf den korrosionsschützend vorbehandelten Eisenoberflächen der in Serie behandelten Bauteile

A :

gemittelte Fläche der Bauteile in m²

In a preferred process according to the invention, the continuous throw assumes at least the following value in liters per square meter of metallic surfaces of zinc and iron treated in order to obtain as much as required, but not more than, 20,000 for a coating of zirconium and / or titanium to be achieved necessary to deliver to pretreatment solution and proceed as economically as possible in this way: $${\mathrm{VW}}_{\mathrm{C}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot \left({\tilde{\mathrm{x}}}^{\mathrm{Zn}}\cdot {\tilde{\mathrm{S}}}^{\mathrm{Zn}}+{\tilde{\mathrm{x}}}^{\mathrm{Fe}}\cdot {\tilde{\mathrm{S}}}^{\mathrm{Fe}}\right)\cdot \tilde{\mathrm{A}}-{\widetilde{\mathrm{VW}}}_{\mathrm{a}}$$

VW _C :

continuous throw in liters;

VW _a :

averaged throw by extraction in liters with the proviso that $${\widetilde{\mathrm{VW}}}_{\mathrm{a}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot \left({\tilde{\mathrm{x}}}^{\mathrm{Zn}}\cdot {\tilde{\mathrm{S}}}^{\mathrm{Zn}}+{\tilde{\mathrm{x}}}^{\mathrm{Fe}}\cdot {\tilde{\mathrm{S}}}^{\mathrm{Fe}}\right)\cdot \tilde{\mathrm{A}};$$

x ^Zn :

averaged proportion of zinc surfaces in terms of total zinc and iron surface area of a series of treated components;

x ^Fe :

average fraction of iron surfaces relative to the total surface area of zinc and iron of a series of treated components;

S ^Zn :

average layer coverage in mmol / m ² based on the elements zirconium and / or titanium on the corrosion-protective pretreated zinc surfaces of the components treated in series; and

S ^Fe :

averaged coating layer in mmol / m ² based on the elements zirconium and / or titanium on the corrosion-protective pretreated iron surfaces of the components treated in series

A :

average area of the components in m ²

It should be noted that for the respective average values is always averaged over the same treated metallic surface, wherein the smallest unit over which can be averaged, the respective component to be treated itself.

nicht überschreitet, wobei für das molare Verhältnis der Gesamtmenge an Fluor zur Gesamtmenge der Elemente Zirconium und/oder Titan in der Ergänzungslösung folgende Bedingung erfüllt vorliegt: $${\mathrm{z}}_{\mathrm{E}}<\frac{\mathrm{0},\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}}+\mathrm{6}$$

Preferred upper limits for the continuously discharged pretreatment solution are processes according to the invention in which the continuous throw in liters per per square meter of metallic surfaces of zinc and iron treated in series has the value $${\mathrm{VW}}_{\mathrm{C}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{0.4\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot \left({\tilde{\mathrm{x}}}^{\mathrm{Zn}}\cdot {\tilde{\mathrm{S}}}^{\mathrm{Zn}}+{\tilde{\mathrm{x}}}^{\mathrm{Fe}}\cdot {\tilde{\mathrm{S}}}^{\mathrm{Fe}}\right)\cdot \tilde{\mathrm{A}}-{\widetilde{\mathrm{VW}}}_{\mathrm{a}}$$

does not exceed, wherein for the molar ratio of the total amount of fluorine to the total amount of the elements zirconium and / or titanium in the supplementary solution the following condition is satisfied: $${\mathrm{z}}_{\mathrm{e}}<\frac{\mathrm{0}.\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}}+\mathrm{6}$$

Scattering and layering are interdependent variables, so that both in quasi-continuous and in discontinuous operation, the measurement of the actual coating layer (S, S _i ) with knowledge of the bath concentration of zirconium and / or titanium is sufficient to specify on the setting of the continuous or discontinuous Verwurfes the target state with respect to layer support for other components and an optimally protected against corrosion Lackhaftgrund. In the method according to the invention can thus be made for the part of the Verwurfes that is actively auszuspeisen, an effective control that requires only the monitoring of the amount of zirconium and / or titanium in the pretreatment solution and on the iron and zinc surfaces.
The layer supports (S, S _i ) based on the elements zirconium and / or titanium can be determined immediately after the pretreatment of the component by means of X-ray fluorescence analysis on the respective treated metal surface as described above.
In a preferred embodiment, the discontinuous Verwurf is carried out immediately after the first rinse, wherein the first sink is preferably carried out by means of a so-called wet holding ring by spraying the components with the first rinse water, wherein the rinse water again preferably at least partially fed as part of the supplement solution in the pretreatment solution becomes. This ensures that the determination of the layer support takes place as promptly as possible with the actual pretreatment, so that an optimal adjustment of the pretreatment solution can be effected almost directly via the regulation of the cast due to the layer support. In this context, it is also preferred that the Verwurf occurs quasi-continuously or if possible discontinuously as possible after each pretreatment of only a small number n of components.

besonders bevorzugt zumindest: $${\mathrm{VW}}_{\mathrm{d}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{2,8\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot \mathrm{0},3\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot {\displaystyle \sum _{\mathrm{i}}^{\mathrm{n}}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}}-{\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}$$

insbesondere bevorzugt zumindest: $${\mathrm{VW}}_{\mathrm{d}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{2,8\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot \mathrm{0},7\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot {\displaystyle \sum _{\mathrm{i}}^{\mathrm{n}}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}}-{\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}$$

bzw. zumindest: $${\mathrm{VW}}_{\mathrm{C}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot \mathrm{0},\mathrm{1}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot \bar{\mathrm{A}}-{\overline{\mathrm{VW}}}_{\mathrm{a}}$$

besonders bevorzugt zumindest: $${\mathrm{VW}}_{\mathrm{C}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot \mathrm{0},3\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot \bar{\mathrm{A}}-{\overline{\mathrm{VW}}}_{\mathrm{a}}$$

insbesondere bevorzugt zumindest: $${\mathrm{VW}}_{\mathrm{C}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot \mathrm{0},7\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot \bar{\mathrm{A}}-{\overline{\mathrm{VW}}}_{\mathrm{a}}$$

In a simplified and therefore preferred embodiment of the inventive method in which the Verwurf takes place at least partially by active continuous or discontinuous feeding of pretreatment solution, the respective at least following Verwurf is set: $${\mathrm{VW}}_{\mathrm{d}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{\mathrm{0}.\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot \mathrm{0}.\mathrm{1}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot {\displaystyle \underset{\mathrm{i}}{\overset{\mathrm{n}}{\Sigma }}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}}-{\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}$$

particularly preferably at least: $${\mathrm{VW}}_{\mathrm{d}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{2.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot \mathrm{0}.3\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot {\displaystyle \underset{\mathrm{i}}{\overset{\mathrm{n}}{\Sigma }}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}}-{\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}$$

particularly preferably at least: $${\mathrm{VW}}_{\mathrm{d}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{2.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot \mathrm{0}.7\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot {\displaystyle \underset{\mathrm{i}}{\overset{\mathrm{n}}{\Sigma }}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}}-{\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}$$

or at least: $${\mathrm{VW}}_{\mathrm{C}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot \mathrm{0}.\mathrm{1}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot \tilde{\mathrm{A}}-{\widetilde{\mathrm{VW}}}_{\mathrm{a}}$$

particularly preferably at least: $${\mathrm{VW}}_{\mathrm{C}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot \mathrm{0}.3\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot \tilde{\mathrm{A}}-{\widetilde{\mathrm{VW}}}_{\mathrm{a}}$$

particularly preferably at least: $${\mathrm{VW}}_{\mathrm{C}}=\frac{{\mathrm{z}}_{\mathrm{e}}-\mathrm{2}.\mathrm{4}}{\mathrm{2}.\mathrm{8th}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{me}}\left({\mathrm{z}}_{\mathrm{e}}-\mathrm{6}\right)}\cdot \mathrm{0}.7\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}\cdot \tilde{\mathrm{A}}-{\widetilde{\mathrm{VW}}}_{\mathrm{a}}$$

The simplification in the setting of the at least required discontinuous or continuous Verwurfes (VW _c , VW _d ) is that the adjustment is made independently of the coating layer, but it is accepted that the proportion of free fluoride is in the respective limits, which just still ensure a sufficient conversion layer formation or not yet detrimental deterioration thereof.

In a particular embodiment of the method according to the invention, at least 80% of the surfaces of the component will be formed by surfaces of the substrates iron, zinc and aluminum, more preferably at least 50% of the surfaces of the component being metallic surfaces of the substrates iron and / or zinc, again preferably at least 10%, particularly preferably at least 20%, of the metallic surfaces of the component are selected from surfaces of the substrate iron. As the surfaces of the substrates iron, zinc and aluminum are also their alloys if their main alloying constituent is formed by the respective substrate element.

The process according to the invention may be followed by further process steps for surface treatment. In a preferred method, after bringing into contact with the passivating aqueous pretreatment solution with or without intermediate rinsing steps, a coating with an organic binder system, preferably a powder coating or dip coating, more preferably an electrodeposition coating, more preferably a cathodic electrodeposition coating. In the case of subsequent dip coating, in particular a subsequent electrocoating, preferably no drying step takes place after bringing into contact with the passivating aqueous pretreatment solution and before the dip coating, wherein a drying step is characterized by performing technical measures for drying the surfaces of the component, for example, by supplying thermal energy or by supplying a dry air flow.

After the inventive treatment of the components in series, ie after contacting by means of the passivating aqueous pretreatment solution, and before a possible coating with an organic binder system, in a preferred embodiment, no further treatment step with an aqueous solution, in which the solution more contains 10% of the proportion of the passivating aqueous pretreatment solution of water-soluble compounds of the elements zirconium and / or titanium, in particular no further such treatment step, serving on at least one metal surface of the component, a coating containing substrate-foreign metallic or semi-metallic elements with a layer of more than Form 0.1 mmol / m ² based on these substrate-foreign elements. As already mentioned, such aftertreatment is often detrimental to the previously produced passivation by means of the pretreatment solution. "Substrate foreign" in this context is any element that is not the main alloying element of the substrate in question.

In a further preferred method according to the invention, immediately after bringing into contact with the passivating aqueous pretreatment solution, a rinsing step is carried out by bringing the components into contact with a rinsing solution present in a system tank, during which part of the rinsing solution is serially treated during the anti-corrosive treatment of the components and replaced by an at least equal volume of a complementary rinse solution containing a total of less than 10 ^-5 mol / L of water-soluble compounds of the elements zirconium and / or titanium, and preferably less than 10 ^-4 mol / L of water-soluble compounds containing a Source of fluoride ions, based on the element contains fluorine. Also in this case, it should be ensured that an enrichment of active components from the passivating aqueous pretreatment solution in the rinse solution is tolerated only to a certain extent, since otherwise damage to the passive layer can not be completely ruled out.

For economic reasons, however, it is preferred that in the rinsing step the throw of rinsing solution per treated in series total surface area of the components is less than 2 liters / m ² . However, due to the comparatively low bath concentration of zirconium and / or titanium in the passivating aqueous pretreatment solution, this upper limit can always be maintained without additional measures for working up the rinse solution being necessary.

It is furthermore preferred if at least part of the discarded rinsing solution is fed as a supplementary solution into the system tank of the passing aqueous pretreatment, with regularly additionally dosing a more concentrated supplementary solution for maintaining the bath concentration of water-soluble compounds of the elements zirconium and / or titanium in the passivating aqueous Pretreatment solution will be necessary.

In the context of the present invention, the water-soluble compounds of the elements zirconium and / or titanium are therefore not restricted to any particular class of compounds both in the pretreatment solution and in the supplemental solutions, but preferred are oxyfluorides of the respective elements, particularly preferably the fluoroacids and salts thereof. However, it is also possible to use basic zirconium carbonate or titanyl sulfate, these compounds then having to be reacted with a corresponding amount of fluoride-releasing compounds because of the ratio of fluorides dissolved in water according to the invention to compounds of zirconium and / or titanium dissolved in water in order to form an adequate supplementary solution.

Water-soluble compounds which are a source of fluoride ions and to which extent the process according to the invention can be based are, for example, hydrofluoric acid, ammonium bifluoride and sodium fluoride or the abovementioned oxyfluorides and fluoro acids of the elements zirconium and / or titanium.

Claims (17)

1. A method for the anti-corrosion treatment of a plurality of metal surfaces of components in series that comprise zinc and/or iron, in which each of said components is brought into contact with a passivating aqueous pretreatment solution, located in a system tank, at a temperature of less than 50 °C, the passivating aqueous pretreatment solution containing one or more water-soluble compounds of the elements zirconium and/or titanium and one or more water-soluble compounds that are a source for fluoride ions, and being brought into contact for such a time that, on the metal surfaces of zinc and/or iron, a coating layer of at least 0.1 mmol/m² based on the elements zirconium and/or titanium is formed, although none of these metal surfaces comprises a coating layer of greater than 0.7 mmol/m² based on the elements zirconium and/or titanium, and, during the anti-corrosion treatment of the components in series, some of the passivating aqueous pretreatment solution in the system tank being rejected and replaced by a part by volume, which is in total at least the same size, of one or more additional solutions by metered addition into the system tank in such a way that the concentration of the elements zirconium and/or titanium in the passivating aqueous pretreatment solution is maintained in the form of water-soluble compounds, characterized in that a concentration of the elements zirconium and/or titanium in the passivating aqueous pretreatment solution is maintained in the form of water-soluble compounds of at least 0.05 mmol/L but of a total of less than 0.8 mmol/L in the system tank, and the molar ratio of the total amount of fluorine in the form of water-soluble compounds that are a source for fluoride ions to the total amount of the elements zirconium and/or titanium in the form of water-soluble compounds in the metered total volume of the additional solutions is less than the same ratio in the passivating aqueous pretreatment solution, but no less than 4.5, and the rejection of passivating aqueous pretreatment solution in liters per square meter of metal surfaces of zinc and iron treated in series assumes at least the following value: $$\mathrm{VW}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot {\mathrm{10}}^{-\mathrm{1}}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}$$

   

   VW: rejection of pretreatment solution in L/m²;

   ${\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}:$

   

   concentration of zirconium and/or titanium in the pretreatment solution in mmol/L;

   Z_E: molar ratio of the total amount of fluorine in the form of water-soluble compounds that are a source for fluoride ions to the total amount of the elements zirconium and/or titanium in the form of water-soluble compounds in the metered total volume of the additional solutions with the proviso that the following applies: $${\mathrm{z}}_{\mathrm{E}}<\frac{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}}+\mathrm{6}$$

   
2. The method according to claim 1, characterized in that, for the molar ratio of the total amount of fluorine in the form of water-soluble compounds that are a source for fluoride ions to the total amount of the elements zirconium and/or titanium in the form of water-soluble compounds in the metered total volume of the additional solutions, the following condition is met: $${\mathrm{z}}_{\mathrm{E}}<\frac{\mathrm{0},\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}}+\mathrm{6}$$

   
3. The method according to claim 2, characterized in that the rejection of passivating aqueous pretreatment solution is not greater than the following value in liters per square meter of the metal component treated in series: $$\mathrm{VW}=\frac{7\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}\right)}{0,4\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot {\mathrm{10}}^{-\mathrm{1}}\mathrm{mmol}{\mathrm{m}}^{-\mathrm{2}}$$

   

   VW: rejection of pretreatment solution in L/m²;

   ${\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}:$

   

   concentration of zirconium and/or titanium in the pretreatment solution in mmol/L;

   Z_E : molar ratio of the total amount of fluorine in the form of water-soluble compounds that are a source for fluoride ions to the total amount of the elements zirconium and/or titanium in the form of water-soluble compounds in the metered total volume of the additional solutions
4. The method according to one or more the preceding claims, characterized in that the molar ratio of the total amount of fluorine in the form of water-soluble compounds that are a source for fluoride ions to the total amount of the elements zirconium and/or titanium in the form of water-soluble compounds in the metered total volume of the additional solutions is no less than 5.0, preferably no less than 5.5.
5. The method according to one or more of the preceding claims, characterized in that the molar ratio of the total amount of the elements zirconium and/or titanium in the form of water-soluble compounds in each case to the total amount of one of the elements calcium, magnesium, aluminum, boron, iron, manganese or tungsten, in each case in the form of water-soluble compounds in the metered total volume of the additional solutions, is greater than 5:1.
6. The method according to one or more of the preceding claims, characterized in that the passivating aqueous pretreatment solution in the system tank contains in total less than 0.55 mmol/L, preferably in total less than 0.325 mmol/L of water-soluble compounds of the elements zirconium and/or titanium.
7. The method according to one or more the preceding claims, characterized in that the pH of the passivating aqueous pretreatment solution is no less than 3.0, preferably no less than 3.5, but no greater than 5.0, preferably no greater than 4.5.
8. The method according to one or more of the preceding claims, characterized in that the temperature of the passivating aqueous pretreatment solution is no higher than 45 °C, preferably no higher than 40 °C, particularly preferably no higher than 35 °C.
9. The method according to one or more the preceding claims, characterized in that the passivating aqueous pretreatment solution is rejected by dragging out pretreatment solution with each component from the series of components to be treated and by actively feeding out pretreatment solution in each case from the pretreatment system tank.
10. The method according to claim 9, characterized in that the rejection takes place by actively feeding out passivating aqueous pretreatment solution intermittently after pretreating a particular number n of components i, the intermittent rejection assuming at least the following value in liters for a number n of components i treated in series: $${\mathrm{VW}}_{\mathrm{d}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot {\displaystyle \sum _{\mathrm{i}}^{\mathrm{n}}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}}-{\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}$$

    

    VW_d : intermittent rejection in liters;

    ${\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}:$

    

    rejection by drag-out by n components in liters with the proviso that the following applies: $${\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}\le \frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot {\displaystyle \sum _{\mathrm{i}}^{\mathrm{n}}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}};$$

    

    ${\mathrm{x}}_{\mathrm{1}}^{\mathrm{Zn}}:$

    

    proportion of zinc surfaces based on the total surface area of zinc and iron of the i-th component treated in series;

    ${\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}:$

    

    proportion of iron surfaces based on the total surface area of zinc and iron of the i-th component treated in series;

    ${\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}:$

    

    coating layer in mmol/m² based on the elements zirconium and/or titanium on the anti-corrosive pretreated zinc surface of the i-th component treated in series; and

    ${\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}:$

    

    coating layer in mmol/m² based on the elements zirconium and/or titanium on the anti-corrosive pretreated iron surfaces of the i-th component treated in series;

    A_i: total surface area of the metal surfaces of zinc and iron of the i-th component treated in series; and

    n: positive natural number {n ∈ N | n ≥1}
11. The method according to claim 10, characterized in that the intermittent rejection in liters for a number n of components i treated in series does not exceed the value $${\mathrm{VW}}_{\mathrm{d}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{0},\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot {\displaystyle \sum _{\mathrm{i}}^{\mathrm{n}}}\left({\mathrm{x}}_{\mathrm{i}}^{\mathrm{Zn}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Zn}}+{\mathrm{x}}_{\mathrm{i}}^{\mathrm{Fe}}\cdot {\mathrm{S}}_{\mathrm{i}}^{\mathrm{Fe}}\right)\cdot {\mathrm{A}}_{\mathrm{i}}-{\mathrm{VW}}_{\mathrm{a}}^{\mathrm{n}}$$

    

    and,
    for the molar ratio of the total amount of fluorine in the form of water-soluble compounds that are a source for fluoride ions to the total amount of the elements zirconium and/or titanium in the form of water-soluble compounds in the metered total volume of the additional solutions, the following condition is met: $${\mathrm{z}}_{\mathrm{E}}<\frac{\mathrm{0},\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}}+\mathrm{6}$$

    
12. The method according to claim 9, characterized in that the rejection takes place by actively feeding out passivating aqueous pretreatment solution and the rejected pretreatment solution is replaced with one or more additional solutions continuously throughout the pretreatment of the components in series, preferably by feeding a constant volume flow of replaced additional solution into the pretreatment system tank, the continuous rejection of passivating aqueous pretreatment solution preferably being achieved predominantly by an overflow of an open system tank.
13. The method according to claim 12, characterized in that the continuous rejection assumes at least the following value in liters per square meter of metal surfaces of zinc and iron treated in series: $${\mathrm{VW}}_{\mathrm{C}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot \left({\bar{\mathrm{x}}}^{\mathrm{Zn}}\cdot {\bar{\mathrm{S}}}^{\mathrm{Zn}}+{\bar{\mathrm{x}}}^{\mathrm{Fe}}\cdot {\bar{\mathrm{S}}}^{\mathrm{Fe}}\right)\cdot \bar{\mathrm{A}}-{\overline{\mathrm{VW}}}_{\mathrm{a}}$$

    

    VW_C: continuous rejection in liters;

    VW _a: averaged rejection by drag-out in liters with the proviso that the following applies: $${\overline{\mathrm{VW}}}_{\mathrm{a}}\le \frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{2},\mathrm{8}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot \left({\bar{\mathrm{x}}}^{\mathrm{Zn}}\cdot {\bar{\mathrm{S}}}^{\mathrm{Zn}}+{\bar{\mathrm{x}}}^{\mathrm{Fe}}\cdot {\bar{\mathrm{S}}}^{\mathrm{Fe}}\right)\cdot \bar{\mathrm{A}};$$

    

    x ^Zn: averaged proportion of zinc surfaces based on the total surface areas of zinc and iron of a series of treated components;

    -Fex ^Fe: averaged proportion of iron surfaces based on the total surface areas of zinc and iron of a series of treated components;

    S ^Zn: averaged coating layer in mmol/m² based on the elements zirconium and/or titanium on the anti-corrosive pretreated zinc surfaces of the components treated in series; and

    S ^Fe: averaged coating layer in mmol/m² based on the elements zirconium and/or titanium on the anti-corrosive pretreated iron surfaces of the components treated in series

    A : averaged surface area of the components in m²
14. The method according to claim 13, characterized in that the continuous rejection in liters per square meter of metal surfaces of zinc and iron pretreated in series does not exceed the value $${\mathrm{VW}}_{\mathrm{c}}=\frac{{\mathrm{z}}_{\mathrm{E}}-\mathrm{2},\mathrm{4}}{\mathrm{0},\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}-{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}\left({\mathrm{z}}_{\mathrm{E}}-\mathrm{6}\right)}\cdot \left({\bar{\mathrm{x}}}^{\mathrm{Zn}}\cdot {\bar{\mathrm{S}}}^{\mathrm{Zn}}+{\bar{\mathrm{x}}}^{\mathrm{Fe}}\cdot {\bar{\mathrm{S}}}^{\mathrm{Fe}}\right)\cdot \bar{\mathrm{A}}$$

    

    and,
    for the molar ratio of the total amount of fluorine in the form of water-soluble compounds that are a source for fluoride ions to the total amount of the elements zirconium and/or titanium in the form of water-soluble compounds in the metered total volume of the additional solutions, the following condition is met: $${\mathrm{z}}_{\mathrm{E}}<\frac{\mathrm{0},\mathrm{4}\mathrm{mmol}{\mathrm{L}}^{-\mathrm{1}}}{{\mathrm{c}}_{\mathrm{B}}^{\mathrm{Me}}}+\mathrm{6}$$

    
15. The method according to one or more of the preceding claims, characterized in that, after the contact with the passivating aqueous pretreatment solution, with or without intermediate rinsing steps, there is subsequent dip coating, preferably electrocoating, particularly preferably cathodic electrocoating.
16. The method according to claim 15, characterized in that, after the contact with the passivating aqueous pretreatment solution, there is no subsequent additional pretreatment step with an aqueous solution in which the solution contains more than 10% of the proportion of the passivating aqueous pretreatment solution of water-soluble compounds of the elements zirconium and/or titanium, in particular there is no subsequent additional treatment step of this kind that is used to form, on at least one metal surface of the component, a coating containing substrate-extraneous metal or semi-metal elements and having a coating layer of more than 0.1 mmol/m² based on said substrate-extraneous elements.
17. The method according to one or both of claims 15-16, characterized in that, immediately after the contact with the passivating aqueous pretreatment solution, a rinsing step is carried out by bringing the components into contact with a rinsing solution located in a system tank; during the anti-corrosion treatment of the components in series, some of the rinsing solution being rejected and replaced by a part by volume, which is in total at least the same size, of an additional rinsing solution which contains in total less than 10^-5 mol/L of water-soluble compounds of the elements zirconium and/or titanium and preferably less than 10^-4 mol/L of water-soluble compounds that are a source for fluoride ions, based on the element fluorine.