EP0264151B1 - Process for obtaining phosphate coatings - Google Patents
Process for obtaining phosphate coatings Download PDFInfo
- Publication number
- EP0264151B1 EP0264151B1 EP87201891A EP87201891A EP0264151B1 EP 0264151 B1 EP0264151 B1 EP 0264151B1 EP 87201891 A EP87201891 A EP 87201891A EP 87201891 A EP87201891 A EP 87201891A EP 0264151 B1 EP0264151 B1 EP 0264151B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- alkali
- composite parts
- rinsing
- bath
- process according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/78—Pretreatment of the material to be coated
Definitions
- the invention relates to a method for producing phosphate coatings on composite parts made of steel and galvanized steel by alkaline cleaning, rinsing with an aqueous rinsing bath and zinc phosphating, and its use for preparing these composite parts for the subsequent painting, in particular electrocoating.
- the object of the invention is now to provide a method for producing phosphate coatings on composite parts made of steel and galvanized steel, the use of which does not give rise to the aforementioned disadvantages and which is nevertheless simple in terms of process and can be carried out without significant additional cost.
- the object is achieved by designing the method of the type mentioned at the outset in accordance with the invention in such a way that the cleaned composite parts are rinsed with a rinsing bath containing at least 0.2 g / l alkali borate, at least 0.1 g / l alkali silicate and at least 0. Contains 05 g / l alkali nitrite.
- the term steel is understood to mean unalloyed to low-alloy steel, as it e.g. in the form of sheets for body construction.
- galvanized steel includes e.g. Galvanizing by electrolytic and hot-dip and refers to zinc and zinc alloys, e.g. ZnNi, ZnFe, ZnAl.
- the process step of alkaline cleaning takes place with aqueous alkaline, surfactant-containing solutions and has the goal of removing at least as much oil, grease and dirt from the metal surfaces as is necessary for a subsequent, perfect phosphating.
- Disodium and trisodium phosphate condensed alkali phosphates, alkali silicates, alkali carbonates, alkali borates and alkali hydroxides can be used.
- Complexing agents such as ethylenediaminetetraacetic acid, nitrilotriacetic acid, polyhydroxycarboxylic acid and phosphonates serve to avoid precipitation and to improve cleaning performance.
- titanium phosphate By adding titanium phosphate, the cleaning agent can be activated to activate the subsequent zinc phosphating.
- the surfactants are usually selected from the group of nonionic and anionic products.
- the pH of the solutions is usually in the range from 9 to 12, preferably between 9.5 and 11.5.
- the concentration of the cleaning baths is e.g. 1 to 40 g / l. They can be used in diving and / or spraying at temperatures between 30 and 95 ° C.
- the zinc phosphating processes used in the context of the invention work with aqueous treatment solutions which contain 0.4 to 1.7 g / l Zn and in which the weight ratio of Zn: P2O5 is set to about 1: (6 to 60) and is maintained.
- the phosphating baths can additionally contain one or more further divalent cations. These preferably include Ni, Mn, Mg and Ca. They are usually added in concentrations of 0.1 to 2 g / l, partly incorporated into the phosphate layer and lead to a further improved layer quality under special conditions.
- the phosphating baths also contain at least one oxidizing agent from the group consisting of chlorate, bromate, nitrate, nitrite, peroxide and organic nitro compound, e.g. meta-nitrobenzenesulfonate.
- the dosage is carried out in the amount and manner customary in phosphating technology.
- the phosphating baths can also contain other additives known per se, such as single and complex fluorides, chlorides, sulfates, polyhydroxycarboxylic acids, polyphosphates, ammonium, alkali, copper, cobalt ions and surfactants.
- the phosphating baths are used in spraying and / or dipping at bath temperatures of 25 to 70 ° C and treatment times of 0.45 to 10 minutes.
- the rinsing baths used in the process according to the invention contain additives which are selected, for example, from the group of sodium and potassium borates, sodium and potassium silicates and sodium and potassium nitrite.
- the rinsing treatment can take place in one step or in several steps.
- the cleaned composite parts should be treated with a rinsing bath which Contains alkali borate, alkali silicate and alkali nitrite in a total amount of maximum 5 g / l.
- a further advantageous embodiment of the invention provides for the composite parts to be activated before the zinc phosphating with an activation bath containing titanium phosphate, to which tetraalkali pyrophosphate is added in an amount of at least 1 g / l.
- tetraalkali pyrophosphate as such or e.g. in the form of another pyrophosphate-containing substance and the amount of alkali required for neutralization. It is easiest to add tetrasodium and / or tetrapotassium pyrophosphate to the activation bath.
- the maximum concentration of tetraalkali pyrophosphate is preferably 4 g / l.
- the activation bath gradually loses its effectiveness over time. Accordingly, it is supplemented with a concentrate containing fresh titanium phosphate. In order to avoid an excessive increase in the salt concentration, a part of the bath can be drained off and reattached from time to time.
- the tetraalkali pyrophosphate is preferably metered in such a way that the optimum concentration is maintained in the bath.
- the temperatures of the rinsing and activating baths are preferably kept below 40 ° C.
- the treatment times should be chosen so that a complete exchange of the liquid adhering to the composite parts from the previous treatment stage is ensured. Depending on the shape of the parts and the type of flushing, dipping or spraying - 0.2 to 1 min are sufficient. In many cases, the contact times with the rinsing bath and activation bath are significantly longer due to the specified system dimensions and the transport speed of the workpieces. The advantages of the method according to the invention are particularly evident under these conditions.
- the process according to the invention produces phosphate coatings of high uniformity.
- the formation of stripes and specks is avoided.
- rinsing with a rinsing bath containing alkali borate, silicate and nitrite is sufficient as a condition to to get perfect phosphate coatings.
- the phosphate coatings produced with the method according to the invention can be used with advantage in all fields in which phosphate coatings have been used. However, they are preferably suitable as a preparation of composite parts made of steel and galvanized steel for painting, in particular electro-dip painting.
- Example 1 in which steps 3 and 4 were only rinsed with water and in which the activation bath was free of tetraalkali pyrophosphate, led to deficient phosphate coatings.
- Example 2 shows in particular that the addition in the rinsing baths leads to an improvement, but speck formation on the galvanized area of the composite part is not yet avoided.
- Example 3 illustrates that, with a suitable choice of the rinsing bath, perfect phosphate layers are obtained on the steel parts, but because of the activation bath used without the required addition of tetraalkali pyrophosphate, specks still occur on the galvanized area of the composite parts.
- Example 4 the steel surface is slightly streaky because of the too small amount of effective rinsing constituents provided the phosphate layer is properly formed in the galvanized area.
- Example 5 with the correctly selected additives both in the rinsing bath and in the activation bath leads to flawless results in both areas of the composite parts.
- Example 6 which represents a repetition of Example 5 while omitting a separate activation treatment, shows that in this case too, perfect phosphate layers can be obtained on both surface areas. However, the weight per unit area of the phosphate layers is somewhat higher than in Example 5.
Description
Die Erfindung betrifft ein Verfahren zur Erzeugung von Phosphatüberzügen auf Verbundteilen aus Stahl und verzinktem Stahl durch alkalisches Reinigen, Spülen mit wäßrigem Spülbad und Zinkphosphatierung sowie dessen Anwendung zur Vorbereitung dieser Verbundteile für die anschließende Lackierung, insbesondere Elektrotauchlackierung.The invention relates to a method for producing phosphate coatings on composite parts made of steel and galvanized steel by alkaline cleaning, rinsing with an aqueous rinsing bath and zinc phosphating, and its use for preparing these composite parts for the subsequent painting, in particular electrocoating.
Es ist heute allgemein üblich, Verbundteile aus Stahl und verzinktem Stahl, z.B. Autokarosserien, vor der Elektrotauchlackierung mit einem Zinkphosphatierverfahren zu behandeln, wobei nacheinander die folgenden Behandlungsstufen im Spritz-, Spritztauch- oder Tauchverfahren durchlaufen werden (vgl. DE-A-32 17 145):
- ein- oder mehrstufige alkalische Reinigung
- ein-oder mehrstufige Spülung mit Wasser
- Aktivierung mit einer wäßrigen Titanphosphat-Suspension (falls erforderlich)
- Zinkphosphatierung
- ein- oder mehrstufige Spülung mit Wasser
- meist eine passivierende Nachspülung
- Spülung mit vollentsalztem Wasser
- single or multi-stage alkaline cleaning
- single or multi-stage rinsing with water
- Activation with an aqueous titanium phosphate suspension (if necessary)
- Zinc phosphating
- single or multi-stage rinsing with water
- usually a passivating rinse
- Rinse with deionized water
Bisweilen treten bei Anwendung dieses Arbeitsganges jedoch Schwierigkeiten auf, die sich in der Ausbildung ungleichmäßig gefärbter und unterschiedlich dicker Phosphatschichten äußern. Auf dem verzinkten Stahl können zusätzlich punktförmige oder auch flächige weißlicheHowever, difficulties sometimes arise when using this process, which are manifested in the formation of unevenly colored and differently thick phosphate layers. In addition, punctiform or flat whitish can be used on the galvanized steel
Kristallausblühungen (Stippen) auftreten. Phosphatschichten mit den beschriebenen Eigenschaften können die Abscheidung gleichmäßiger Elektrotauchlackschichten empfindlich stören. Eine genauere Analyse dieser Phänomene ergab, daß sie verstärkt auftreten, wenn die Spülzeiten zwischen alkalischer Reinigung und Zinkphosphatierung übermäßig lang sind und/oder die Spülwässer durch Chlorid und/oder Sulfat verunreinigt sind.Crystal efflorescence (specks) occur. Phosphate layers with the properties described can severely interfere with the deposition of uniform electrocoat layers. A closer analysis of these phenomena showed that they occur more frequently if the rinsing times between alkaline cleaning and zinc phosphating are excessively long and / or the rinsing water is contaminated with chloride and / or sulfate.
Aufgabe der Erfindung ist es nun, ein Verfahren zur Erzeugung von Phosphatüberzügen auf Verbundteilen aus Stahl und verzinktem Stahl bereitzustellen, bei dessen Anwendung die vorgenannten Nachteile nicht auftreten und das dennoch verfahrensmäßig einfach und ohne wesentlichen zusätzlichen Kostenaufwand durchführbar ist.The object of the invention is now to provide a method for producing phosphate coatings on composite parts made of steel and galvanized steel, the use of which does not give rise to the aforementioned disadvantages and which is nevertheless simple in terms of process and can be carried out without significant additional cost.
Die Aufgabe wird gelöst, indem das Verfahren der eingangs genannten Art entsprechend der Erfindung derart ausgestaltet wird, daß man die gereinigten Verbundteile mit Spülbad spült, das mindestens 0,2 g/l Alkaliborat, mindestens 0,1 g/l Alkalisilikat und mindestens 0,05 g/l Alkalinitrit enthält.The object is achieved by designing the method of the type mentioned at the outset in accordance with the invention in such a way that the cleaned composite parts are rinsed with a rinsing bath containing at least 0.2 g / l alkali borate, at least 0.1 g / l alkali silicate and at least 0. Contains 05 g / l alkali nitrite.
Unter dem Begriff Stahl wird un- bis niedriglegierter Stahl verstanden, wie er z.B. in Form von Blechen für den Karosseriebau Verwendung findet. Der Begriff verzinkter Stahl umfaßt z.B. Verzinkungen auf elektrolytischem und auf dem Schmelztauchwege und bezieht sich auf Zink und Zinklegierungen, z.B. ZnNi, ZnFe, ZnAl.The term steel is understood to mean unalloyed to low-alloy steel, as it e.g. in the form of sheets for body construction. The term galvanized steel includes e.g. Galvanizing by electrolytic and hot-dip and refers to zinc and zinc alloys, e.g. ZnNi, ZnFe, ZnAl.
Der Verfahrensschritt der alkalischen Reinigung, der ein-oder mehrstufig sein kann, erfolgt mit wäßrigen alkalischen, tensidhaltigen Lösungen und hat das Ziel, die Metalloberflächen von öl, Fett und Schmutz mindestens so weit zu befreien, wie es für eine anschließende, einwandfreie Phosphatierung erforderlich ist.The process step of alkaline cleaning, the one or can be multi-stage, takes place with aqueous alkaline, surfactant-containing solutions and has the goal of removing at least as much oil, grease and dirt from the metal surfaces as is necessary for a subsequent, perfect phosphating.
Als Komponenten für das anorganische Gerüst des alkalischen Reinigers können u.a. Di- und Trinatriumphosphat, kondensierte Alkaliphosphate, Alkalisilikate, Alkalicarbonate, Alkaliborate und Alkalihydroxide verwendet werden. Komplexbildner, wie Ethylendiamintetraessigsäure, Nitrilotriessigsäure, Polyhydroxycarbonsäure und Phosphonate, dienen dazu, Ausfällungen zu vermeiden und die Reinigungsleistung zu steigern. Durch Zusatz von Titanphosphat kann dem Reiniger eine die nachfolgende Zinkphosphatierung aktivierende Wirkung verliehen werden. Die Tenside werden üblicherweise aus der Gruppe der nichtionogenen und anionaktiven Produkte ausgewählt. Der pH-Wert der Lösungen liegt meist im Bereich von 9 bis 12, vorzugsweise zwischen 9,5 und 11,5.As components for the inorganic framework of the alkaline cleaner, i.a. Disodium and trisodium phosphate, condensed alkali phosphates, alkali silicates, alkali carbonates, alkali borates and alkali hydroxides can be used. Complexing agents such as ethylenediaminetetraacetic acid, nitrilotriacetic acid, polyhydroxycarboxylic acid and phosphonates serve to avoid precipitation and to improve cleaning performance. By adding titanium phosphate, the cleaning agent can be activated to activate the subsequent zinc phosphating. The surfactants are usually selected from the group of nonionic and anionic products. The pH of the solutions is usually in the range from 9 to 12, preferably between 9.5 and 11.5.
Die Konzentration der Reinigungsbäder beträgt z.B. 1 bis 40 g/l. Die Anwendung kann im Tauchen und/oder Spritzen bei Temper aturen zwischen 30 und 95°C erfolgen.The concentration of the cleaning baths is e.g. 1 to 40 g / l. They can be used in diving and / or spraying at temperatures between 30 and 95 ° C.
Die im Rahmen der Erfindung eingesetzten Zinkphosphatierverfahren arbeiten mit wäßrigen Behandlungslösungen, die 0,4 bis 1,7 g/l Zn enthalten und in denen das Gewichtsverhältnis von Zn : P₂O₅ auf etwa 1 : (6 bis 60) eingestellt ist und gehalten wird.The zinc phosphating processes used in the context of the invention work with aqueous treatment solutions which contain 0.4 to 1.7 g / l Zn and in which the weight ratio of Zn: P₂O₅ is set to about 1: (6 to 60) and is maintained.
Die Phosphatierbäder können zusätzlich ein oder mehrere weitere zweiwertige Kationen enthalten. Hierzu zählen vorzugsweise Ni, Mn, Mg und Ca. Sie werden üblicherweise in Konzentrationen von 0,1 bis 2 g/l zugesetzt, zum Teil mit in die Phosphatschicht eingebaut und führen unter speziellen Bedingungen zu einer weiter verbesserten Schichtqualität.The phosphating baths can additionally contain one or more further divalent cations. These preferably include Ni, Mn, Mg and Ca. They are usually added in concentrations of 0.1 to 2 g / l, partly incorporated into the phosphate layer and lead to a further improved layer quality under special conditions.
Die Phosphatierbäder enthalten außerdem mindestens ein Oxidationsmittel aus der Gruppe Chlorat, Bromat, Nitrat, Nitrit, Peroxid und organische Nitroverbindung, z.B. meta-Nitrobenzolsulfonat. Die Dosierung erfolgt in der in der Phosphatiertechnik üblichen Menge und Art und Weise.The phosphating baths also contain at least one oxidizing agent from the group consisting of chlorate, bromate, nitrate, nitrite, peroxide and organic nitro compound, e.g. meta-nitrobenzenesulfonate. The dosage is carried out in the amount and manner customary in phosphating technology.
Die Phosphatierbäder können noch weitere, an sich bekannte Zusätze, wie Einfach- und Komplexfluoride, Chloride, Sulfate, Polyhydroxycarbonsäuren, Polyphosphate, Ammonium-, Alkali-, Kupfer-, Kobaltionen und Tenside enthalten.The phosphating baths can also contain other additives known per se, such as single and complex fluorides, chlorides, sulfates, polyhydroxycarboxylic acids, polyphosphates, ammonium, alkali, copper, cobalt ions and surfactants.
Die Phosphatierbäder werden im Spritzen und/oder Tauchen bei Badtemperaturen von 25 bis 70°C und Behandlungszeiten von 0,45 bis 10 min angewendet.The phosphating baths are used in spraying and / or dipping at bath temperatures of 25 to 70 ° C and treatment times of 0.45 to 10 minutes.
Die innerhalb des erfindungsgemäßen Verfahrens eingesetzten Spülbäder enthalten Zusätze, die z.B. aus der Gruppe der Natrium- und Kaliumborate, Natrium- und Kaliumsilikate und Natrium-und Kaliumnitrit ausgewählt sind. Die Spülbehandlung kann in einer Stufe oder in mehreren Sufen erfolgen. Gemäß einer bevorzugten Ausgestaltung der Erfindung sollten die gereinigten Verbundteile mit einem Spülbad behandelt werden, das Alkaliborat, Alkalisilikat und Alkalinitrit in einer Gesamtmenge von maximal 5 g/l enthält.The rinsing baths used in the process according to the invention contain additives which are selected, for example, from the group of sodium and potassium borates, sodium and potassium silicates and sodium and potassium nitrite. The rinsing treatment can take place in one step or in several steps. According to a preferred embodiment of the invention, the cleaned composite parts should be treated with a rinsing bath which Contains alkali borate, alkali silicate and alkali nitrite in a total amount of maximum 5 g / l.
Weiterhin ist es vorteilhaft, die Verbundteile mit einem Spülbad zu behandeln, dessen pH-Wert auf einen Wert im Bereich von 9,5 bis 12,0 eingestellt ist.It is also advantageous to treat the composite parts with a rinsing bath, the pH of which is set to a value in the range from 9.5 to 12.0.
Eine weitere vorteilhafte Ausführungsform der Erfindung sieht vor, die Verbundteile vor der Zinkphosphatierung mit einem Titanphosphat enthaltenden Aktivierungsbad, dem Tetraalkalipyrophosphat in einer Menge von mindestens 1 g/l zugesetzt ist, zu aktivieren. Der Zusatz an Tetraalkalipyrophosphat kann als solcher oder z.B. in Form einer anderen Pyrophosphat enthaltenden Substanz und der zur Neutralisation notwendigen Menge Alkali erfolgen. Am einfachsten ist es, dem Aktivierungsbad Tetranatrium- und/oder Tetrakaliumpyrophosphat zuzugeben. Vorzugsweise beträgt die maximale Konzentration an Tetraalkalipyrophosphat 4 g/l.A further advantageous embodiment of the invention provides for the composite parts to be activated before the zinc phosphating with an activation bath containing titanium phosphate, to which tetraalkali pyrophosphate is added in an amount of at least 1 g / l. The addition of tetraalkali pyrophosphate as such or e.g. in the form of another pyrophosphate-containing substance and the amount of alkali required for neutralization. It is easiest to add tetrasodium and / or tetrapotassium pyrophosphate to the activation bath. The maximum concentration of tetraalkali pyrophosphate is preferably 4 g / l.
Während des Betriebes reichern sich in dem Spülbad oder in den Spülbädern Verunreinigungen aus der vorausgehenden Verfahrensstufe an. Um diese nicht über ein störendes Niveau ansteigen zu lassen, wird den Spülbädern Frischwasser zugegeben, dem die erforderlichen Mengen an Alkaliborat, Alkalisilikat und Alkalinitrit zugesetzt sind. Hierbei können die aus dem Reinigerübertrag stammenden Komponenten mit berücksichtigt werden. Es hat sich als günstig erwiesen, den Zusatz der genannten Substanzen auf Basis einer Kontrolle der elektrischen Leitfähigkeit der Spülbäder vorzunehmen.During operation, impurities from the preceding process step accumulate in the rinsing bath or in the rinsing baths. In order not to let these rise above a disturbing level, fresh water is added to the rinsing baths, to which the required amounts of alkali borate, alkali silicate and alkali nitrite have been added. The components from the cleaner transfer can also be taken into account. It has proven to be advantageous to add the substances mentioned on the basis of checking the electrical conductivity of the rinsing baths.
Das Aktivierungsbad verliert im Laufe der Zeit zunehmend an Wirksamkeit. Es wird dementsprechend mit frischem Titanphosphat enthaltendem Konzentrat ergänzt. Um einen zu starken Anstieg der Salzkonzentration zu vermeiden, kann kontinuierlich oder von Zeit zu Zeit ein Teil des Bades abgelassen und neu angesetzt werden. Die Dosierung des Tetraalkalipyrophosphates erfolgt vorzugsweise in der Art, daß die optimale Konzentration im Bad aufrechterhalten wird.The activation bath gradually loses its effectiveness over time. Accordingly, it is supplemented with a concentrate containing fresh titanium phosphate. In order to avoid an excessive increase in the salt concentration, a part of the bath can be drained off and reattached from time to time. The tetraalkali pyrophosphate is preferably metered in such a way that the optimum concentration is maintained in the bath.
Die Temperaturen der Spül- und Aktivierbäder werden vorzugsweise unter 40°C gehalten. Die Behandlungszeiten sollten so gewählt werden, daß ein vollständiger Austausch der an den Verbundteilen haftenden Flüssigkeit aus der vorausgegangenen Behandlungsstufe gewährleistet ist. Hi erzu sind je nach Form der Teile und Art der Spülung-Tauchen oder Spritzen - 0,2 bis 1 min ausreichend. Vielfach sind die Kontaktzeiten mit Spülbad und Aktivierungsbad wegen der vorgegebenen Anlagendimensionen und der Transportgeschwindigkeit der Werkstücke wesentlich länger. Insbesondere unter diesen Bedingungen kommen die Vorteile des erfindungsgemäßen Verfahrens deutlich zum Ausdruck.The temperatures of the rinsing and activating baths are preferably kept below 40 ° C. The treatment times should be chosen so that a complete exchange of the liquid adhering to the composite parts from the previous treatment stage is ensured. Depending on the shape of the parts and the type of flushing, dipping or spraying - 0.2 to 1 min are sufficient. In many cases, the contact times with the rinsing bath and activation bath are significantly longer due to the specified system dimensions and the transport speed of the workpieces. The advantages of the method according to the invention are particularly evident under these conditions.
Bei ordnungsgemäßer Ausführung werden mit dem erfindungsgemäßen Verfahren Phosphatüberzüge von hoher Gleichmäßigkeit erzeugt. Die Entstehung von Streifen und Stippen wird vermieden. Ordnungsgemäß bedeutet hierbei, daß für den Fall der Zinkphosphatierung ohne vorherige Aktivierung mit Titanphosphat enthaltendem Aktivierungsbad bereits die Spülung mit Alkaliborat, -silikat und -nitrit enthaltendem Spülbad als Bedingung ausreicht, um einwandfreie Phosphatüberzüge zu erhalten. Sofern jedoch eine derartige Aktivierung beabsichtigt ist, ist es erforderlich, die zusätzliche Bedingung des Tetraalkalipyrophosphat-Zusatzes zum Aktivierungsbad zu erfüllen.When properly carried out, the process according to the invention produces phosphate coatings of high uniformity. The formation of stripes and specks is avoided. Properly means here that in the case of zinc phosphating without prior activation with an activation bath containing titanium phosphate, rinsing with a rinsing bath containing alkali borate, silicate and nitrite is sufficient as a condition to to get perfect phosphate coatings. However, if such activation is intended, it is necessary to meet the additional requirement of adding tetraalkali pyrophosphate to the activation bath.
Die mit dem erfindungsgemäßen Verfahren erzeugten Phosphatüberzüge sind auf allen Gebieten, auf denen Phosphatüberzüge angewendet wurden, mit Vorteil einsetzbar. Vorzugsweise sind sie jedoch als Vorbereitung von Verbundteilen aus Stahl und verzinktem Stahl für die Lackierung, insbesondere die Elektrotauchlackierung, geeignet.The phosphate coatings produced with the method according to the invention can be used with advantage in all fields in which phosphate coatings have been used. However, they are preferably suitable as a preparation of composite parts made of steel and galvanized steel for painting, in particular electro-dip painting.
Die Erfindung wird anhand des folgenden Beispiels näher und beispielsweise erläutert.The invention is explained in more detail and, for example, using the following example.
Autokarosserien als Verbundteile aus Stahl und verzinktem Stahl wurden nach folgendem Arbeitsgang behandelt:
- 1. Vorentfetten mit einem wäßrigen alkalischen Reiniger aus
- 2. Hauptentfetten mit einem wäßrigen alkalischen Reiniger aus
- 3. Spülen mit wäßrigem Spülbad unterschiedlicher Zusammensetzung (siehe Tabelle 1, Spalte 2) bei max. 40°C und 30 sec im Spritzen
- 4. Spülen mit wäßrigem Spülbad unterschiedlicher Zusammensetzung (siehe Tabelle 1, Spalte 2)
- 5. Aktivieren mit einem wäßrigen Aktivierungsbad von 1 g/l Titanphosphat-haltigem Aktivierungsmittel und verschiedenen Zusätzen (siehe Tabelle 1, Spalte 3)
- 6. Phosphatierung mit einer wäßrigen Lösung aus
- 7. Spülen im Spritzen
- 8. Spülen im Tauchen
- 9. Passivierendes Spülen im Tauchen
- 10. Spülen mit vollentsalztem Wasser im Tauchen und Spritzen
Die Zusammensetzung der Bäder aus den Verfahrensschritten 3, 4 und 5 wurde variiert und die dabei resultierende Phosphatschichtausbildung beurteilt. Die Ergebnisse sind in der Tabelle zusammengefaßt.
- 1. Pre-degrease with an aqueous alkaline cleaner
- 2. Main degrease with an aqueous alkaline cleaner
- 3. Rinse with an aqueous rinsing bath of different composition (see table 1, column 2) at max. 40 ° C and 30 sec in spraying
- 4. Rinsing with an aqueous rinsing bath of different composition (see table 1, column 2)
- 5. Activation with an aqueous activation bath of 1 g / l titanium phosphate-containing activating agent and various additives (see Table 1, column 3)
- 6. Phosphating with an aqueous solution
- 7. Rinse in a syringe
- 8. Rinse while diving
- 9. Passivating rinsing while diving
- 10. Rinse with deionized water while diving and spraying
The composition of the baths from process steps 3, 4 and 5 was varied and the resulting phosphate layer formation was assessed. The results are summarized in the table.
Aus der Tabelle ergibt sich, daß Beispiel 1, bei dem in den Stufen 3 und 4 lediglich mit Wasser gespült wur de und bei dem das Aktivierungsbad frei von Tetraalkalipyrophosphat war, zu mangelhaften Phosphatüberzügen führte. Beispiel 2 zeigt insbesondere, daß der Zusatz in den Spülbädern zwar zu einer Verbesserung führt, aber eine Stippenbildung auf dem verzinkten Bereich des Verbundteiles noch nicht vermieden ist. Beispiel 3 veranschaulicht, daß bei geeigneter Wahl des Spülbades zwar auf den Stahlteilen einwandfreie Phosphatschichten erhalten werden, aber wegen des verwendeten Aktivierungsbades ohne den erforderlichen Tetraalkalipyrophosphat-Zusatz auf dem verzinkten Bereich der Verbundteile weiterhin Stippen auftreten. In Beispiel 4 ist wegen der zu geringen Zusatzmenge an wirksamen Spülbestandteilen bei einwandfreier Phosphatschichtausbildung im verzinkten Bereich die Stahloberfläche leicht streifig. Beispiel 5 mit den korrekt gewählten Zusätzen sowohl im Spülbad als auch im Aktivierungsbad führt auf beiden Bereichen der Verbundteile zu einwandfreien Ergebnissen.From the table it follows that Example 1, in which steps 3 and 4 were only rinsed with water and in which the activation bath was free of tetraalkali pyrophosphate, led to deficient phosphate coatings. Example 2 shows in particular that the addition in the rinsing baths leads to an improvement, but speck formation on the galvanized area of the composite part is not yet avoided. Example 3 illustrates that, with a suitable choice of the rinsing bath, perfect phosphate layers are obtained on the steel parts, but because of the activation bath used without the required addition of tetraalkali pyrophosphate, specks still occur on the galvanized area of the composite parts. In example 4, the steel surface is slightly streaky because of the too small amount of effective rinsing constituents provided the phosphate layer is properly formed in the galvanized area. Example 5 with the correctly selected additives both in the rinsing bath and in the activation bath leads to flawless results in both areas of the composite parts.
Beispiel 6, das eine Wiederholung des Beispiels 5 unter Fortlassung einer separaten Aktivierungsbehandlung darstellt, zeigt, daß auch in diesem Fall auf beiden Oberflächenbereichen einwandfreie Phosphatschichten erhalten werden können. Allerdings ist das Flächengewicht der Phosphatschichten im Vergleich zu Beispiel 5 etwas höher.Example 6, which represents a repetition of Example 5 while omitting a separate activation treatment, shows that in this case too, perfect phosphate layers can be obtained on both surface areas. However, the weight per unit area of the phosphate layers is somewhat higher than in Example 5.
Claims (6)
- Process of producing phosphate coatings on composite parts of steel and galvanized steel by means of alcaline cleaning, rinsing with an aqueous rinsing bath and zinc phosphating characterized in that the cleaned composite parts are rinsed with a rinsing bath, which contains at least 0,2 g/l alkali borate, at least 0,1 g/l alkali silicate and at least 0,05 g/l alkali nitrite.
- Process according to claim 1, characterized in that the cleaned composite parts are rinsed with a rinsing bath, which contains alkali borate, alkali silicate and alkali nitrite in a total concentration of up to 5 g/l.
- Process according to claim 1 or 2, characterized in that the cleaned composite parts are rinsed with a rinsing bath having a pH value in the range of 9,5 to 12,0.
- Process according to claim 1, 2 or 3 characterized in that the composite parts are activated prior to the zinc phosphating with a titanium phosphate containing activating bath to which tetra-alkali pyrophosphate in an amount of at least 1 g/l is added.
- Process according to claim 4, characterized in that the composite parts are activated with an activating bath to which tetra-alkali pyrophospate in an amount of up to 4 g/l is added.
- Use of the process according to one or more of the claims 1 to 5 for preparing composite parts of steel and galvanized steel for subsequent painting, in particular for electrophoretic immersion painting.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3635343 | 1986-10-17 | ||
| DE19863635343 DE3635343A1 (en) | 1986-10-17 | 1986-10-17 | METHOD FOR THE PRODUCTION OF PHOSPHATE SURFACES |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0264151A1 EP0264151A1 (en) | 1988-04-20 |
| EP0264151B1 true EP0264151B1 (en) | 1991-03-13 |
Family
ID=6311908
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP87201891A Expired - Lifetime EP0264151B1 (en) | 1986-10-17 | 1987-10-03 | Process for obtaining phosphate coatings |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4867853A (en) |
| EP (1) | EP0264151B1 (en) |
| JP (1) | JP2607549B2 (en) |
| AU (1) | AU7991387A (en) |
| CA (1) | CA1306929C (en) |
| DE (2) | DE3635343A1 (en) |
| ES (1) | ES2020552B3 (en) |
| GB (1) | GB2199850B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3814287A1 (en) * | 1988-04-28 | 1989-11-09 | Henkel Kgaa | POLYMERS TITANIUM PHOSPHATES, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE FOR ACTIVATING METAL SURFACES BEFORE ZINC PHOSPHATION |
| US5597465A (en) * | 1994-08-05 | 1997-01-28 | Novamax Itb S.R.L. | Acid aqueous phosphatic solution and process using same for phosphating metal surfaces |
| US5714047A (en) * | 1994-08-05 | 1998-02-03 | Novamax Itb S.R.L. | Acid aqueous phosphatic solution and process using same for phosphating metal surfaces |
| US7611588B2 (en) * | 2004-11-30 | 2009-11-03 | Ecolab Inc. | Methods and compositions for removing metal oxides |
| US8097575B2 (en) | 2004-12-02 | 2012-01-17 | Harris Research, Inc. | Composition and method for cleaning and neutralizing a surface |
| DE102008047533A1 (en) | 2008-09-16 | 2010-04-15 | Sachtleben Chemie Gmbh | Process for the preparation of titanium-IV-phosphate |
| DE102013202286B3 (en) * | 2013-02-13 | 2014-01-30 | Chemetall Gmbh | Use of a silane, silanol or / and siloxane additive to prevent specks on zinc-containing metal surfaces and use of the coated metal substrates |
| US11643731B2 (en) | 2017-08-31 | 2023-05-09 | Chemetall Gmbh | Method for nickel-free phosphating metal surfaces |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2815328A (en) * | 1955-02-25 | 1957-12-03 | Nat Aluminate Corp | Corrosion inhibitor composition for aqueous liquids |
| BE567592A (en) * | 1957-11-29 | |||
| GB878307A (en) * | 1959-04-30 | 1961-09-27 | Pyrene Co Ltd | Improvements relating to the cleaning and phosphate coating of metallic surfaces |
| GB932970A (en) * | 1961-05-19 | 1963-07-31 | Pyrene Co Ltd | Improvements relating to the cleaning and phosphate coating of metallic surfaces |
| FR1291347A (en) * | 1961-06-06 | 1962-04-20 | Parker Ste Continentale | Iron and steel spray phosphating process |
| DE1287892B (en) * | 1965-03-31 | Metallgesellschaft Ag | ||
| SE332330B (en) * | 1965-10-19 | 1971-02-01 | Parker Ste Continentale | |
| JPS5319974B2 (en) * | 1972-10-04 | 1978-06-23 | ||
| JPS5811515B2 (en) * | 1979-05-11 | 1983-03-03 | 日本ペイント株式会社 | Composition for forming a zinc phosphate film on metal surfaces |
| DE3217145A1 (en) * | 1982-05-07 | 1983-11-10 | Gerhard Collardin GmbH, 5000 Köln | Method for cleaning, degreasing and activating metal surfaces |
| AU2448684A (en) * | 1983-03-02 | 1984-09-06 | Parker Chemical Company | Metal treatment before phosphate coating |
-
1986
- 1986-10-17 DE DE19863635343 patent/DE3635343A1/en not_active Withdrawn
-
1987
- 1987-08-19 CA CA000544880A patent/CA1306929C/en not_active Expired - Lifetime
- 1987-10-03 ES ES87201891T patent/ES2020552B3/en not_active Expired - Lifetime
- 1987-10-03 DE DE8787201891T patent/DE3768599D1/en not_active Expired - Lifetime
- 1987-10-03 EP EP87201891A patent/EP0264151B1/en not_active Expired - Lifetime
- 1987-10-07 US US07/106,165 patent/US4867853A/en not_active Expired - Lifetime
- 1987-10-15 JP JP62258497A patent/JP2607549B2/en not_active Expired - Lifetime
- 1987-10-19 AU AU79913/87A patent/AU7991387A/en not_active Abandoned
- 1987-10-19 GB GB8724432A patent/GB2199850B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63186879A (en) | 1988-08-02 |
| JP2607549B2 (en) | 1997-05-07 |
| EP0264151A1 (en) | 1988-04-20 |
| US4867853A (en) | 1989-09-19 |
| GB8724432D0 (en) | 1987-11-25 |
| DE3635343A1 (en) | 1988-04-28 |
| ES2020552B3 (en) | 1991-08-16 |
| DE3768599D1 (en) | 1991-04-18 |
| GB2199850A (en) | 1988-07-20 |
| GB2199850B (en) | 1990-06-13 |
| AU7991387A (en) | 1988-04-21 |
| CA1306929C (en) | 1992-09-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| DE3118375C2 (en) | ||
| EP0312176B1 (en) | Process for applying conversion coatings | |
| EP0261704B1 (en) | Process for producing phosphate coatings on metal surfaces | |
| EP0304108A1 (en) | Metal-phosphating process | |
| EP0149720B1 (en) | Process for after passivating phosphated metal surfaces using titanium and/or manganese and/or cobalt and/or nickel and/or copper cations containing solutions | |
| EP0045110A1 (en) | Method for the production of phosphate coatings on iron and steel surfaces, and its use | |
| DE2247888C3 (en) | Preparations and methods for cleaning and activating iron and / or zinc surfaces and concentrates of these agents | |
| EP0327153B1 (en) | Process for applying phosphate coatings to metals | |
| EP0264151B1 (en) | Process for obtaining phosphate coatings | |
| EP0134895B1 (en) | Process and compounds for applying accelerated and grain-refined phosphate coatings to metallic surfaces | |
| EP0031103B1 (en) | Method for the pretreatment of metal surfaces prior to phosphatizing | |
| EP1290242B1 (en) | Method for treating or pre-treating components comprising aluminium surfaces | |
| EP0111223A1 (en) | Process for phosphatizing metallic surfaces, and solutions for use therein | |
| DE19808440A1 (en) | Aqueous solution and process for phosphating metallic surfaces | |
| EP0603921A1 (en) | Process for forming phosphate coatings | |
| EP0121274A1 (en) | Process for phosphating metal surfaces | |
| EP0258922A1 (en) | Process for producing phosphate coatings and their use | |
| DE4232292A1 (en) | Process for phosphating galvanized steel surfaces | |
| EP0224190B1 (en) | Process for activating metallic surfaces prior to zinc phosphating | |
| DE2402702A1 (en) | METAL PHOSPHATING METHOD | |
| DE2342558C3 (en) | Process for phosphating metals | |
| DE3217145A1 (en) | Method for cleaning, degreasing and activating metal surfaces | |
| DE2738282A1 (en) | METHOD FOR APPLYING PHOSPHATE | |
| EP0096753B1 (en) | Process for the electroless production of corrosion-inhibiting layers on structural parts of aluminium | |
| EP0127204B1 (en) | Phosphating process for composite metals |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): BE DE ES FR IT NL SE |
|
| 17P | Request for examination filed |
Effective date: 19880901 |
|
| 17Q | First examination report despatched |
Effective date: 19891123 |
|
| GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
| AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): BE DE ES FR IT NL SE |
|
| REF | Corresponds to: |
Ref document number: 3768599 Country of ref document: DE Date of ref document: 19910418 |
|
| ET | Fr: translation filed | ||
| ITF | It: translation for a ep patent filed |
Owner name: STUDIO JAUMANN |
|
| PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
| 26N | No opposition filed | ||
| EAL | Se: european patent in force in sweden |
Ref document number: 87201891.6 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 20000925 Year of fee payment: 14 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 20001002 Year of fee payment: 14 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20001012 Year of fee payment: 14 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: ES Payment date: 20001020 Year of fee payment: 14 Ref country code: BE Payment date: 20001020 Year of fee payment: 14 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20001218 Year of fee payment: 14 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20011004 Ref country code: ES Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20011004 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: BE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20011031 |
|
| BERE | Be: lapsed |
Owner name: METALLGESELLSCHAFT A.G. Effective date: 20011031 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20020501 |
|
| EUG | Se: european patent has lapsed |
Ref document number: 87201891.6 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20020628 |
|
| NLV4 | Nl: lapsed or anulled due to non-payment of the annual fee |
Effective date: 20020501 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20020702 |
|
| REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |
|
| REG | Reference to a national code |
Ref country code: ES Ref legal event code: FD2A Effective date: 20021113 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED. Effective date: 20051003 |