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

In the present invention, a series of components having a metal surface made of iron and / or zinc are brought into contact with a passivation pretreatment aqueous solution placed in a system tank, and the passivation pretreatment aqueous solution is made of zirconium and / or The present invention relates to a corrosion prevention treatment method containing a compound of an elemental titanium and a fluoride ion source. In the method according to the invention, a portion of this pretreatment solution is discarded and replaced by one or more such replenishment solutions in at least equal parts in total by weighing into the pretreatment system tank. The amount of waste as a function of the molar ratio of fluoride ions to the content of zirconium and / or titanium completely eliminates the use of chemicals to regulate pickling rates or to stabilize ion loading. Even if this is the case, the replenisher solution must be metered and added to ensure that the anticorrosion treatment is permanently satisfactory, so that zirconium in the immobilization pretreatment aqueous solution is used. And / or the concentration in the form of a water-soluble compound of titanium element is maintained.

Modern production lines, which pre-treat for anti-corrosion coatings before applying paint, are not only expected to combine high production rates with high levels of material consumption per unit time, but also for this purpose. Combined with changes in the type of bath chemical consumption and load used for, it provides a high degree of flexibility regarding the components to be processed. In continuous manufacturing operations, it is not uncommon to use the same pretreatment bath to coat different components with different surface areas made of different metallic materials, which is common in the automotive supplier industry. In contrast, in the painting line of the production line of the automobile industry, the same automobile body is usually used in a pretreatment solution of 150 to 450 m.³Immerse in a coating tank containing 3 to 6 m / min at a line speed, thus each about 100 m.²Eighty bodies with a metal surface are pretreated in a continuous operation that allows them to be pretreated per hour.

Continuous and accurate monitoring of the pretreatment process is fundamentally important for optimal administration of the active ingredient and, optionally, conditioned chemicals to the surface treatment of the metal surface of the component. In modern production lines, this type of complexity is that the monitoring and control of the chemical administration process is substantially automated to maintain a lastingly optimal proportion of chemicals in the process bath, material efficiency. And can still be achieved only if it is possible to meet the principles of consistent pretreatment quality.

Specifically, passivation pretreatment of metal components based on an acidic pretreatment aqueous solution of fluorometallates of zirconium and / or titanium elements is increasingly being used due to the toxicity of chromium (VI) compounds. Known as an alternative to the chemical process, it has been established for some time. In general, additional active ingredients are added to such pretreatment solutions, which are intended to further improve corrosion protection and paint adhesion. European Patent Application Publication No. 1 571 237 is cited herein as an example to disclose pretreatment solutions suitable for different metal surfaces containing up to 5000 ppm zirconium and / or titanium, and up to 100 ppm free fluoride. There is. The solution contains additional components selected from chlorates, bromates, nitrites, nitrates, permanganates, vanadium salts, hydrogen peroxides, tungstates, molybdates, or their respective associated acids. It may be further contained. Organic polymers may be present as well. After treatment with such a solution, the metal surface may be rinsed with a further passivation solution.

Thus, the pretreatment bath for producing a passivation conversion coating on the metal surface requires multiple active ingredients that must be replenished regularly, especially during the ongoing operation of the pretreatment bath. To do. In the context of maximum material efficiency, there is a constant need to make pretreatment methods more resource-saving, i.e. to operate them under conditions that can reduce the use of active ingredients.

In this regard, German Patent Application Publication No. 10 2008 038653 recascading the active ingredients of the pretreatment drawn into the rinse with the components back into the rinse water prior to the actual pretreatment, zirconium-based and / Or discloses a method of producing a titanium-based conversion coating. During this pre-rinse step, some of the backcascaded active ingredients cause partial passivation that is completed during subsequent pretreatment. This has already made it possible to reduce the actual amount of active ingredient used for each component processed, thus increasing material efficiency.

Despite this advance in material efficiency, the amount of active ingredient, of course, must be continuously maintained within the control window defined by the type of pretreatment, so the pretreatment bath during ongoing operations. The complexity of maintenance remains very high.

In addition, concentration of the components dissolved in water occurs during the ongoing operation of the pretreatment bath, which represents the reactants of the active component and is pickled or upstream from the metal surface of the treated component. It must be introduced into the pretreatment bath from the treatment step (eg, wet chemical cleaning step). Depending on the material properties of the components to be treated, the type of pretreatment, and the engineering control of the pretreatment process and process, the pretreatment bath thus strives to achieve steady-state equilibrium, but sometimes equilibrium. Concentration is desired for certain components that may adversely affect the results of pretreatment. Therefore, supplementing the active ingredient is not enough. Rather, it is often necessary to use chemicals with a regulatory effect to prevent deterioration of the quality of the pretreatment during the ongoing operation.

German Patent Application Publication No. 10 2008 014465 describes, for example, the anti-corrosion treatment of metal components with a pretreatment solution of fluorometallates of zirconium and / or titanium elements during a continuous pretreatment operation, i.e. an ongoing operation. In the meantime, it is reported that it is essential to maintain the optimum molar ratio of fluoride ions to the element from the zirconium and / or titanium element. Furthermore, it has been proposed to ensure consistent and good anti-corrosion pretreatment by adding a certain amount of fluoride scavenger to the pretreatment bath by weight. Thus, the fluoride scavenger represents a chemical that has a regulatory effect and is preferably selected from compounds that release aluminum ions, calcium ions and / or iron ions in this particular case. In this regard, excessively high relative content of aluminum ions in the pretreatment bath inhibits the formation of titanium-based and / or zirconium-based conversion coatings, resulting in lower layers, especially on the steel surface of the component. It is then demonstrated that it tends to result in a coating of, and thus inadequate corrosion protection.

Therefore, each addition of a fluoride scavenger as a chemical having a regulatory effect to maintain pretreatment performance must result in an accurately predictable concentration of active ingredient in the pretreatment bath. Otherwise, it cannot be guaranteed that the continuous pretreatment of the components will be performed according to the optimum process conditions, that is, the empirically found substance parameter limits. In this regard, the conventional method is based on measurements with ion-selective electrodes and is therefore based on slow-materialized chemical equilibrium, so the addition of direct metrological determination of the total amount of fluoride or free fluoride. There is difficulty. Therefore, deriving the actual variables for setting the target variables with fluoride scavengers depends on the lack of accuracy in terms of time, which depends on the manufacturing process and is an order of magnitude of the processing time of the metal component. May be in. Thus, the consistent quality of continuous anti-corrosion pretreatment with an acidic pretreatment aqueous solution of fluorometallates of zirconium and / or titanium elements, along with the high analytical procedural complexity, has forgotten that it is important. It can only be ensured through the use of significant amounts of conditioning chemicals.

<p><patcit num="1"><text>European Patent Application Publication No. 1 571 237</text></patcit><patcit num="2"><text>German Patent Application Publication No. 10 2008 038653</text></patcit><patcit num="3"><text>German Patent Application Publication No. 10 2008 014465</text></patcit></p>

<p> Therefore, it considerably simplifies the complexity of process engineering for monitoring and controlling process-related bath parameters in the continuous anti-corrosion treatment of components containing metal surfaces with acidic pretreatment aqueous solutions of zirconium and / or titanium element soluble compounds. At the same time, it is an object of the present invention to significantly increase material efficiency with respect to the use of controlled bath chemicals. In addition, a reliable anti-corrosion conversion based on zirconium and / or titanium elements takes place, especially on the iron surface of continuously processed components, followed by interaction with organic primer coatings or organic immersion coatings. The aim was to optimize the process in order to achieve the effect of meeting the high requirements for permanent corrosion protection.</p>

<p> The purpose is a method of anti-corrosion treatment of multiple metal surfaces of components containing zinc and / or iron in a continuous operation, each of which is a mobilized pretreatment aqueous solution located in a system tank. Contacted at temperatures below 50 ° C, the immobilization pretreatment solution comprises one or more water-soluble compounds of zirconium and / or elemental titanium and one or more water-soluble compounds representing a source of fluoride ions. The contact is at least 0.1 mmol / m based on zirconium and / or elemental titanium.²Layer coatings occur on zinc and / or iron metal surfaces, all of which are 0.7 mmol / m based on zirconium and / or titanium elements.²Part of the immobilization pretreatment aqueous solution of the system tank is discarded during the component corrosion protection treatment in continuous operation, in the form of a water-soluble compound, which is carried out during a time that does not have a layer coating exceeding Replaced with one or more replenishment solutions in at least equal parts in total by weighing and adding into the system tank so that the concentration of zirconium and / or elemental titanium in the immobilization pretreatment aqueous solution is maintained. In addition, the concentration of zirconium and / or titanium elements in the immobilization pretreatment aqueous solution in the form of water-soluble compounds is at least 0.05 mmol / L, but the total amount is less than 0.8 mmol / L maintained in the system tank and fluoride. Total amount of fluorine in the form of the water-soluble compound that is the source of ions (hereinafter referred to as "total amount of fluorine", the total amount of zirconium and / or titanium element in the form of the water-soluble compound in the total volume of the added supplementary solution (hereinafter, "total amount of fluorine"). Below, the molar ratio to "total amount of zirconium and / or titanium elements") is less than the same ratio of the immobilization pretreated aqueous solution, but more than 4.5, and the non-per square meter of continuously treated metal surfaces of zinc and iron. The amount of waste (L) of the mobilization pretreatment aqueous solution takes at least the following values, that is, is equal to or greater than the following values:<img file="JP6720175B2_D0001.tif" /><img file="JP6720175B2_D0002.tif" />Is achieved by a method characterized by having.</p>

By adjusting the amount of waste, the method according to the invention does not allow the free fluoride fraction in the pretreatment solution to exceed the values that have already resulted in structural changes in the conversion coating, which are usually corrosion resistant and Accompanied by deterioration of paint adhesion.

In a preferred embodiment of the method according to the invention, the amount of pretreatment solution discarded to achieve the same objective takes at least the following values:<img file="JP6720175B2_D0003.tif" />Particularly preferably, it takes at least the following values:<img file="JP6720175B2_D0004.tif" />

According to the invention, the amount of waste is processed out of the system tank during continuous pretreatment, either by passive withdrawal or by continuous or discontinuous spillover per square meter of the component being processed. The surface area of the component to be (1 m)²) Is the standardized liquid volume of the pretreatment solution.

The continuous pretreatment according to the present invention exists when a plurality of components are contacted with a pretreatment solution placed in a system tank, and the contact of the individual components occurs continuously and thus separately from each other in time. .. The system tank is a container containing a pretreatment solution for continuous passivation pretreatment.

The range of layer coatings set by the method according to the invention based on the elements Zr and / or Ti is the molar concentration of H known using the dry-in-place method.₂ZrF₆And H₂TiF₆It can be measured by X-ray fluorescence (XRF) spectroscopy after calibration based on a metal surface coated with a solution containing. A solution with a known molar concentration is applied to the specified wet film thickness to prepare a calibration sample metal sheet, after which the wet film is completely dried. Measurements of the actual layer coating according to the invention are such that after the pretreated and rinsed surfaces of the component have been dried, or after the pretreatment and the first rinse step, for example, rinse water is applied to multiple spray valves. It can be done on the basis of these calibration sample metal sheets both after the body has been rinsed immediately after the pretreatment as it passes through the so-called wet retention ring, which is applied through the body.

The compound is 1 μS cm at a temperature of 20 ° C.^-1It is "water soluble" in the sense of the present invention when its solubility in deionized water having the following conductivity is at least 1 g / L.

As is apparent from the solution to this problem, the concentration of zirconium and / or titanium elements can be maintained by the metered addition of one or more replenishing solutions into the system tank. The molar ratio of the total amount of fluorine in the form of water-soluble compounds to the total amount of zirconium and / or titanium elements in the form of water-soluble compounds at the total addition of one or more supplementary solutions is less than 4.5. should not do. Below this value, the required amount of the compound of zirconium and / or elemental titanium dissolved in water can be substantially measured, as the compound tends to form a colloidal solution and thus form a precipitate that is hardly soluble. However, it makes it almost impossible to reliably administer such a supplemental solution in an amount useful for maintaining the active ingredient in the pretreatment solution. In a preferred embodiment of the method according to the invention, the molar ratio of the total amount of fluorine to the total amount of zirconium and / or titanium elements in the total amount of the supplement solution thus added is 5.0 or more, particularly preferably 5.5 or more. Conversely, the same ratio in total addition of replenisher solution in the method according to the invention<img file="JP6720175B2_D0005.tif" />Less than, or optionally less than 9.25, the amount of waste required for the pretreatment solution is relative to all covered pretreatment solutions in a manner in which the method according to the invention is substantially still economically useful. Has an upper limit that can be manipulated.

For linguistic simplification, the following refers to only one replenisher solution, but nevertheless, this also makes up for the amount of replenishment solution of the same or different composition discarded, zirconium. Covers the case of weighing in a system tank to maintain the concentration of and / or titanium. From then on, when referring to a replenishment solution, especially its broad or specific properties, this is always the sum of all added replenishment solutions and the resulting average of the wide or specific properties obtained from an overall perspective. Covers.

Due to the controlled disposal of the bath solution and the accompanying addition of the replenishing solution, the method according to the invention adversely affects the concentration of free fluoride in the pretreatment solution on the conversion coating based on zirconium and / or titanium elements. Is restricted so as not to reach. In addition, the method according to the invention is a metric of fluoride scavengers, i.e. compounds that bind to free fluoride and thereby reduce its concentration, as the free fluoride concentration is completely controlled through the disposal of the bath solution. Emphasize that the addition is unnecessary. For certain general conditions regarding the concentration of active ingredient in the pretreatment solution and the coating of the intended layer, the minimum waste amount is semi-empirical, based on the zirconium and titanium elements, as opposed to the zirconium and titanium elements. Up to 0.7 mmol / m according to the conditions found in (1) or the more preferred semi-empirically found conditions (1') and (1 ).²Should be set to. These conditions for minimum waste were dissolved in water relative to the specific concentration of zirconium and / or titanium in the pretreatment solution and the total amount of zirconium and / or titanium in the form of a compound dissolved in water in the replenishing solution. It depends only on the ratio of elemental fluorine elements in the form of the compound. Therefore, in order to comply with the optimum process conditions during the pretreatment, only the concentration of the active ingredient in the form of zirconium and / or titanium elements must be measured and somehow regularly to form a sufficient conversion coating. Must be checked. In the method according to the invention, it is not necessary to monitor the amount of free fluoride in the pretreatment solution.

As described above, the metered addition of fluoride scavengers to the pretreatment solution can be omitted, so these proportions in volume of the replenisher solution added in accordance with the present invention are low for material efficiency reasons. Therefore, the method according to the invention preferably contains calcium, magnesium, aluminum, boron, iron, manganese, or tungsten elements in the form of water-soluble compounds in the total volume of supplementation solution, with the total amount of zirconium and / or titanium elements. A method in which the molar ratio to each total amount of is greater than 5: 1, particularly preferably greater than 10: 1.

A further advantage of the method according to the invention is that a sufficient layer coating of zirconium and / or titanium for corrosion protection and for adhesion to subsequent applied organic primers has already been achieved at relatively low concentrations of active ingredient. That is what has been done. In this regard, the preferred method according to the invention for material efficiency is that the mobilized pretreated aqueous solution in the system tank totals less than 0.65 mmol / L, particularly preferably less than 0.55 mmol / L, particularly preferably. It contains less than 0.325 mmol / L of water-soluble compounds of zirconium and / or titanium elements. Low concentrations of active ingredient also reduce the steady-state proportion of these compounds introduced into the downstream rinsing stage for carry-over. This is usually equally advantageous as the additional contact time of the component with the composition containing the active ingredient often results in a decrease in corrosion resistance, and the rinsing step is usually carried over from the pretreatment system tank. It must be maintained so that it is virtually free of minutes. In a preferred embodiment of the method according to the invention, this is not necessary and special means for reducing the proportion of active ingredient in the system tank during the rinsing stage, eg, an increased spill setting, i.e. the amount of rinsing solution discarded. May be omitted.

In a particularly economical method according to the invention, to ensure that sufficient amounts of free fluoride are present in the pretreatment solution of the system tank under conventional process conditions to form a conversion coating. The amount of waste of fluorinated aqueous solution is the following value in liters per square meter of continuously treated metal components:<img file="JP6720175B2_D0006.tif" />Below, however<img file="JP6720175B2_D0007.tif" />

For good stability and conversion of the components of the metal surface, in a preferred method according to the present invention, the pH value of the passivating pretreatment solution is 3.0 or higher is an advantageous al, particularly preferably 3.5 or more However, it is preferably 5.0 or less, and particularly preferably 4.5 or less.

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

The method according to the invention is preferably carried out at a relatively low temperature so that the evaporation loss of the pretreatment solution in the system tank can be ignored. In the preferred method according to the invention, the temperature of the passivation pretreatment aqueous solution is correspondingly 45 ° C. or lower, particularly preferably 40 ° C. or lower, particularly preferably 35 ° C. or lower.

Disposal of the pretreatment solution provided by the method according to the invention can only occur semi-continuously or discontinuously during the anticorrosion treatment of multiple components for process related reasons. The continuous treatment process according to the invention leaves a certain amount of pretreatment solution from the system tank with each component being treated. The proportion of waste drawn with all treated components is virtually discrete and therefore discontinuous, depending on the particular treatment conditions and the geometry of the components. In addition, the extracted portion of the waste is to blow off the component, for example, by rotating or tilting the component while immersed in the pretreatment solution, or when the component is lifted from the pretreatment system tank. Can only be conditionally controlled by. However, such process means are complex and usually not justified by any particular value added. However, prior art methods are, in principle, operated so that the components do not regularly withdraw the pretreatment solution on a consumable scale, typically less than 50 mL per square meter of treated surface. Hereinafter, when quasi-continuous or discontinuous disposal is referred to, this corresponds only to the amount of pretreatment solution actively discharged, and the passively drawn waste portion is always treated. It must be taken into account that each component is discarded discontinuously.

According to the present invention, the disposal of the passivated pretreatment aqueous solution thus draws the pretreatment solution together with each component of the series of components to be treated and positively draws the pretreatment solution from the pretreatment system tank, respectively. It is preferably done by both discharging.

For discontinuous disposal, the amount of pretreatment solution that is actively discharged can be adapted to the layer coating deposited on the components during the pretreatment process based on the zirconium and / or titanium elements and is achieved. The pretreatment solution required for the zirconium and / or titanium layer coating to be discharged is discharged, but not more than necessary, and thus proceeds as economically as possible.

During the discontinuous operation, the preferred method is the discontinuous disposal VW of the passivation pretreatment aqueous solution._dHowever, the discontinuous disposal is performed discontinuously after the predetermined number n of the component i is preprocessed, and the discontinuous disposal is at least the following liter value for the continuously processed number n of the component i:<img file="JP6720175B2_D0008.tif" />However,<img file="JP6720175B2_D0009.tif" />Is the way to be.

According to the present invention, the preferred upper limit of the pretreatment solution discharged discontinuously is preferably the amount (liter) discarded discontinuously with respect to the number n of continuously treated components i.<img file="JP6720175B2_D0010.tif" />The molar ratio of the total amount of fluorine in the replenishing solution to the total amount of zirconium and / or titanium elements does not exceed the value of:<img file="JP6720175B2_D0011.tif" />Including how to meet.

Of course, the disposal to be set by the present invention can also be performed semi-continuously. In this mode of operation, it is preferable to actively drain the immobilized pretreatment aqueous solution and continuously replace the pretreatment solution that is discarded during the pretreatment of the component with a replenishment solution for disposal. In particular, it is preferable to supply a constant amount of flow to replace the replenishment solution into the pretreatment system tank, and continuous disposal of the immobilized pretreatment aqueous solution is mainly carried out by overflow of the open system tank. Is preferable.

In this context, "mainly" means that more than 50%, preferably more than 80%, of the controllable waste pretreatment solution is removed from the system tank by spillage, which is a debilitating effect on the components. Or it should be understood to mean including a portion of the waste that is inevitably caused by the wet film attached to the component. Thus, spill represents a particularly preferred method of disposal by active discharge. Alternatively, continuous disposal can also be carried out by discharging a constant volumetric flow rate from the system tank.

The preferred method according to the invention requires an amount of pretreatment for the zirconium and / or titanium layer coating to be achieved, but no further, and thus as economically as possible. The amount that is continuously discarded to drain the solution is the following value in liters per square meter of continuously treated zinc and iron metal surfaces:<img file="JP6720175B2_D0012.tif" />At least take, however<img file="JP6720175B2_D0013.tif" />Is.

In this regard, it should be noted that each average value is always averaged on the same treated metal surface and the smallest unit in which averaging can occur is the individual component being processed itself.

According to the present invention, the preferred upper limit of the continuously discharged pretreatment solution is preferably the amount of continuously discarded liters per square meter of continuously treated metal surfaces of zinc and iron.<img file="JP6720175B2_D0014.tif" />The molar ratio of the total amount of fluorine in the total volume of the added replenishing solution to the total amount of zirconium and / or titanium elements, which does not exceed the value of:<img file="JP6720175B2_D0015.tif" />Including how to meet.

The amount discarded and the layer coating are independent variables, so when you have knowledge of the bath concentration of zirconium and / or titanium in both quasi-continuous and discontinuous operations, the actual layer coating<img file="JP6720175B2_D0016.tif" />It is sufficient to measure and by setting the amount to be discarded continuously or discontinuously, the target conditions for layer coating for additional components and the paint primers that provide optimal protection against corrosion are predetermined. Thus, in the method according to the invention, effective control is possible for some of the actively discharged waste, and control is possible for zirconium and / on the iron and zinc surfaces in the pretreatment solution and monitored. Or only the amount of titanium is needed.

Layer coating based on zirconium and / or titanium elements<img file="JP6720175B2_D0017.tif" />Can be measured as described above immediately after pretreatment of the components by X-ray fluorescence spectroscopy on each treated metal surface. In a preferred embodiment, discontinuous disposal is performed immediately after the first rinse step, where the first rinse step is preferably the so-called wet retention ring by spraying the component with the first rinse water. The rinse water is then at least partially fed to the pretreatment solution, preferably as part of the replenishing solution. In this way, the measurement of the layer coating is as close as possible to the actual pretreatment so that the optimum setting of the pretreatment solution can be made almost directly by controlling the amount of waste based on the layer coating. It is guaranteed to be done at the same time. In this regard, the disposal is also preferably done semi-continuously, or if it is done discontinuously, after each pretreatment of only a few n components.

In a simplified and therefore preferred embodiment of the method according to the invention, where disposal is at least partially performed by active continuous or discontinuous discharge of the pretreatment solution, in each case at least the following waste amounts:<img file="JP6720175B2_D0018.tif" />Especially preferably, at least:<img file="JP6720175B2_D0019.tif" />Especially preferably, at least:<img file="JP6720175B2_D0020.tif" />Or at least:<img file="JP6720175B2_D0021.tif" />Especially preferably, at least:<img file="JP6720175B2_D0022.tif" />Especially preferably, at least:<img file="JP6720175B2_D0023.tif" />Should be set.

The simplification of setting at least the required discontinuous or continuously discarded amount (VWc, VWd) is that the setting is done independently of the layer coating, but only one of the free fluorides. It is accepted that the sections are within their respective limits to ensure the formation of a sufficient fluoride coating or deterioration that is not yet disadvantageous.

In a particular embodiment of the method according to the invention, at least 80% of the surface of the component is formed by the surface of a substrate of iron, zinc, and aluminum, and particularly preferably at least 50% of the surface of the component is iron. And / or represents the metal surface of the zinc substrate, then preferably at least 10%, particularly preferably at least 20% of the metal surface of the component is selected from the surface of the iron substrate. If the main alloying component is formed by the respective base element, the surface of the iron, zinc, and aluminum bases is also covered by those alloys.

The method according to the invention can be followed by further method steps for surface treatment. In a preferred method, an organic binder system, preferably a powder coating or immersion coating step, particularly preferably an electroimmersion coating step, particularly preferably a coating step using a cathode electroimmersion coating step, was brought into contact with the passivation pretreatment aqueous solution. It is then performed with or without a rinsing step. In the case of the next dip coating step, particularly in the case of the next electro dip coating step, preferably, after contact with the passivation pretreatment aqueous solution and before the dip coating step, the drying step is not performed and the drying is performed. The process is characterized in that technical means for drying the surface of the component are carried out, for example, by supplying thermal energy or by supplying a stream of dry air.

In a preferred embodiment, the zirconium and / or elemental titanium elements are used in a preferred embodiment after the components have been treated in a continuous manner according to the present invention, i.e. after contact with an aqueous immobilization pretreatment solution and before a possible coating step using an organic binder system. No further treatment steps were performed with aqueous solutions containing more than 10% of the proportion of the immobilization pretreatment solution of the water-soluble compound, especially for coatings containing foreign metal or semi-metal elements. 0.1 mmol / m based on these base material foreign elements²No further treatment steps are performed that are used to form a coating with more than one layer coating on at least one metal surface of the component. As already mentioned, such post-treatment is often detrimental to the passivation previously produced by the pre-treatment solution. In this regard, "base material heterogeneity" is any element that is not the major alloy component of a particular base material.

In a more preferred method according to the invention, a rinsing step is performed immediately after contacting the component with the immobilized pretreatment aqueous solution by contacting the component with the rinsing solution placed in the system tank to corrode the component in continuous operation. During the prevention treatment, some of the rinse solution is discarded and 10 water-soluble compounds of zirconium and / or titanium element representing a fluoride ion source based on the elemental fluorine element.^-5Less than mol / L, preferably 10^-4Replaced by at least equal volume portions of the replenishing rinse solution containing less than mol / L in total. Even in this case, concentration of the active ingredient from the passivation pretreatment aqueous solution in the rinse solution is only allowed to some extent, as damage to the passivation layer cannot be completely eliminated if this is not the case. Should be guaranteed.

However, for economic reasons, the amount of rinsing solution discarded in the rinsing process per continuously treated whole surface of the component is 2 L / m.²It is preferably less than. However, due to the relatively low bath concentrations of zirconium and / or titanium in the passivation pretreatment aqueous solution, this upper limit can always be maintained without the need for additional means for treating the rinse solution. ..

It is even more preferred that at least a portion of the discarded rinse solution be supplied as a replenishing solution to the system tank of the immobilization pretreatment aqueous solution, with the water-soluble compounds of zirconium and / or titanium elements in the immobilization pretreatment aqueous solution. In order to maintain the bath concentration, it is necessary to administer a more concentrated supplement solution on a regular basis.

Thus, within the scope of the invention, the water-soluble compounds of the zirconium and / or titanium elements are not limited to certain compounds for supply either in the pretreatment solution or in the supplementary solution, but for each element. Oxyfluoride, fluoroic acid and salts thereof are particularly preferred. However, it is also possible to use basic zirconium carbonate or titanyl sulphate, and these compounds are water-soluble fluorides, water-soluble zirconium and / or, as previously defined in accordance with the present invention. Due to the ratio of elemental titanium to the compound, it must be reacted with the corresponding amount of fluoride-releasing compound so that a suitable replenishing solution can be formed.

Water-soluble compounds representing a source of fluoride ions can be used, for example, for hydrofluoric acid, ammonium difluoride and sodium fluoride, or zirconium and / or elemental titanium, as long as they can be used for the methods according to the invention. Includes the aforementioned oxyfluoride and fluoroic acid.<u style="single">Preferred embodiments of the present invention include:</u><u style="single">[1] A method of anticorrosion treatment of multiple metal surfaces of components containing zinc and / or iron in a continuous operation, each of which is in a passivation pretreatment aqueous solution located in a system tank. Contacted at a temperature below ° C, the passivation pretreatment aqueous solution comprises one or more water-soluble compounds of zirconium and / or elemental titanium and one or more water-soluble compounds representing a source of fluoride ions. Including, said contact is at least 0.1 mmol / m based on zirconium and / or titanium element</u>^{<u style="single">2</u>}<u style="single">Layer coatings occur on zinc and / or iron metal surfaces, all of which are 0.7 mmol / m based on zirconium and / or titanium elements.</u>^{<u style="single">2</u>}<u style="single">Part of the immobilization pretreatment aqueous solution of the system tank is discarded during the component corrosion protection treatment in continuous operation, in the form of a water-soluble compound, which is carried out during a time that does not have a layer coating of more than. By weighing and adding into the system tank so that the concentration of zirconium and / or titanium element in the immobilization pretreatment aqueous solution is maintained, it is replaced with at least one or more replenishment solutions with equal parts in total. The concentration of zirconium and / or titanium elements in the immobilization pretreatment aqueous solution in the form of a water-soluble compound is at least 0.05 mmol / L, but a total of less than 0.8 mmol / L is maintained in the system tank and fluoride ions. The molar ratio of the total amount of fluorine in the form of the water-soluble compound that is the source of the water-soluble compound to the total amount of zirconium and / or titanium element in the form of the water-soluble compound in the total volume of the added supplementary solution is the immobilization pretreatment. Less than the same ratio of aqueous solutions but greater than or equal to 4.5, the waste amount (L) of immobilized pretreated aqueous solution per continuously treated square meter of zinc and iron metal surfaces takes at least the following values:</u><img file="JP6720175B2_D0024.tif" />VW:<u style="single">Waste amount of pretreatment solution (L / m)</u>^{<u style="single">2</u>}<u style="single">)、</u><img file="JP6720175B2_D0025.tif" /><img file="JP6720175B2_D0026.tif" /><u style="single">A method characterized by having.</u><u style="single">[2] The molar ratio of the total amount of fluorine in the form of a water-soluble compound representing the source of fluoride ions to the total amount of zirconium and / or titanium elements in the form of a water-soluble compound in the total volume of the supplemented solution added. , The following conditions:</u><img file="JP6720175B2_D0027.tif" /><u style="single">The method according to claim 1, wherein the method is satisfied.</u><u style="single">[3] The amount of waste of passivated aqueous solution is the following value in liters per square meter of continuously treated metal components:</u><img file="JP6720175B2_D0028.tif" /><u style="single">Below, however</u>VW:<u style="single">Waste amount of pretreatment solution (L / m)</u>^{<u style="single">2</u>}<u style="single">)、</u><img file="JP6720175B2_D0029.tif" /><u style="single">The method according to [2], which is characterized by being.</u><u style="single">[4] The molar ratio of the total amount of fluorine in the form of a water-soluble compound representing the source of fluoride ions to the total amount of zirconium and / or titanium elements in the form of a water-soluble compound in the total volume of the supplemented solution added. , 5.0 or higher, preferably 5.5 or higher, according to any one of [1] to [3].</u><u style="single">[5] Elements of calcium, magnesium, aluminum, boron, iron, manganese, or tungsten in the form of water-soluble compounds in the total volume of zirconium and / or titanium in the form of water-soluble compounds and the total volume of the supplemented solution added. The method according to any one of [1] to [4], wherein the molar ratio with the total amount of each one of them is larger than 5: 1.</u><u style="single">[6] The passivation pretreatment aqueous solution in the system tank comprises a total of less than 0.55 mmol / L, preferably less than 0.325 mmol / L, of water-soluble compounds of zirconium and / or titanium elements. The method described in any of [1] to [5].</u><u style="single">[7] Any of [1] to [6], wherein the pH value of the passivation pretreatment aqueous solution is 3.0 or more, preferably 3.5 or more, but 5.0 or less, preferably 4.5 or less. The method described in.</u><u style="single">[8] Any of [1] to [7], wherein the temperature of the passivation pretreatment aqueous solution is 45 ° C or lower, preferably 40 ° C or lower, particularly preferably 35 ° C or lower. The method described in.</u><u style="single">[9] Disposal of passivation pretreatment aqueous solution is to draw out the pretreatment solution together with each component of the series of components to be treated and actively discharge each pretreatment solution out of the pretreatment system tank. The method according to any one of [1] to [8], characterized in that it is performed by.</u><u style="single">[10] Disposal by active discharge of the passivation pretreated aqueous solution is discontinuous after a predetermined number n of component i has been pretreated, and discontinuous disposal is the continuously treated number n of component i. For at least the following liter values:</u><img file="JP6720175B2_D0030.tif" /><u style="single">However,</u><img file="JP6720175B2_D0031.tif" /><u style="single">The method according to [9], characterized in that.</u><u style="single">[11] The amount (liters) discarded discontinuously for the number n of components i processed continuously is</u><img file="JP6720175B2_D0032.tif" /><u style="single">The total amount of fluorine in the form of a water-soluble compound representing the source of fluoride ions, not exceeding the value of, relative to the total amount of zirconium and / or elemental titanium in the form of a water-soluble compound in the total volume of the supplemented solution added. The condition that the molar ratio is as follows:</u><img file="JP6720175B2_D0033.tif" /><u style="single">The method according to [10], which comprises satisfying.</u><u style="single">[12] In the disposal, the immobilized pretreatment aqueous solution is actively discharged, and the pretreatment solution discarded during the pretreatment of the component is continuously replaced with one or more replenishment solutions in a continuous operation, preferably pretreatment. It is carried out by supplying a certain amount of flow of replenishment solution to be replaced in the treatment system tank, and the continuous disposal of the immobilization pretreatment aqueous solution is preferably carried out mainly by the overflow of the open system tank. , The method described in [9].</u><u style="single">[13] The amount of continuously discarded is the following value in liters per square meter of continuously treated zinc and iron metal surfaces:</u><img file="JP6720175B2_D0034.tif" /><u style="single">At least take, however</u><img file="JP6720175B2_D0035.tif" /><u style="single">The method according to [12], characterized in that.</u><u style="single">[14] The amount of continuous waste in liters per square meter of continuously treated zinc and iron metal surfaces,</u><img file="JP6720175B2_D0036.tif" /><u style="single">The total amount of fluorine in the form of a water-soluble compound representing the source of fluoride ions, not exceeding the value of, relative to the total amount of zirconium and / or elemental titanium in the form of a water-soluble compound in the total volume of the supplemented solution added. The condition that the molar ratio is as follows:</u><img file="JP6720175B2_D0037.tif" /><u style="single">The method according to [13], which comprises satisfying.</u><u style="single">[15] The immersion coating step, preferably the electroimmersion coating step, particularly preferably the cathode electroimmersion coating step, is carried out after contact with the immobilization pretreatment aqueous solution with or without the rinsing step. The method according to any one of [1] to [14].</u><u style="single">[16] After contact with the passivation pretreatment aqueous solution, a further treatment step is performed with an aqueous solution containing more than 10% of the passivation pretreatment aqueous solution of the water-soluble compound of zirconium and / or titanium element. Not, especially on at least one metal surface of the component, 0.1 mmol / m</u>^{<u style="single">2</u>}<u style="single">It is characterized in that no further treatment steps used to form a coating containing a substrate heterogeneous metal or metalloid element with a layer coating above these substrate heterogeneous elements are performed. , [15].</u><u style="single">[17] A rinse step is performed immediately after contact with the passivation pretreatment aqueous solution by contacting the component with a rinse solution located in the system tank, during the component corrosion prevention treatment in continuous operation. A portion of the solution is discarded and replaced with at least an equal volume of replenishment rinse solution, which contains a total of 10 water-soluble compounds of zirconium and / or elemental titanium.</u>^{<u style="single">-5</u>}<u style="single">10 water-soluble compounds representing a fluoride ion source based on less than a molar / L, preferably a fluoride element</u>^{<u style="single">-4</u>}<u style="single">The method according to [15] or [16], which comprises less than a molar / L.</u>