EP0109110A1 - Process for preparing metallic surfaces for electropainting - Google Patents
Process for preparing metallic surfaces for electropainting Download PDFInfo
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- EP0109110A1 EP0109110A1 EP83201504A EP83201504A EP0109110A1 EP 0109110 A1 EP0109110 A1 EP 0109110A1 EP 83201504 A EP83201504 A EP 83201504A EP 83201504 A EP83201504 A EP 83201504A EP 0109110 A1 EP0109110 A1 EP 0109110A1
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- metal surfaces
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- phosphating solution
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- phosphate
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- 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
- C23C22/05—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 using aqueous solutions
- C23C22/06—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 using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/07—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 using aqueous solutions using aqueous acidic solutions with pH less than 6 containing phosphates
- C23C22/08—Orthophosphates
- C23C22/20—Orthophosphates containing aluminium cations
Definitions
- the invention relates to a method for pretreating metal surfaces for electrocoating by applying phosphate layers by means of phosphating solutions based on zinc phosphate.
- the essential components of acidic zinc phosphate solutions are zinc and phosphate ions and generally one or more oxidizing accelerators. It is known that the layer weight and the layer quality can be changed if further substances are added to the phosphating solution. For example, it is known from GB-PS 866 377 to add tartrations in the spraying process so that a dense phosphate layer of lighter weight is produced than would be the case in the absence of tartrate.
- a further step forward was the realization that thin, finely crystalline layers are desired for the subsequent electrocoating.
- the phosphate layers produced using phosphating solutions with additions of citrate and tartrate had the abovementioned properties, they proved to be disadvantageous due to the poor adhesion, if the coated articles were to be subjected to cold deformation.
- This finding led to the assumption that the application of paint by the method of cathodic dip painting is an unsuitable way when high paint adhesion is desired during cold working, and that in cases of intended cold working, paints based on organic solvents should be used or the anodic one Electrocoating is to be used as the painting process.
- the object of the invention is to provide a method for pretreating metal surfaces for electrocoating set, which avoids the disadvantages or difficulties of the known methods and is able to produce phosphate layers on which deposited by methods of electrocoating, even under the strain of cold forming, firmly adheres.
- 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 metal surfaces are brought into contact with a phosphating solution which contains aluminum ions in an amount of 0.05 to 0.4 g / l, and in which is the weight ratio of aluminum to zinc 1:50 to 1: 100.
- the required aluminum content of the phosphating solution is set; by introducing the aluminum in the form of a compound which is soluble in aqueous, acidic solution.
- Suitable forms of incorporation are aluminum hydroxide or aluminum salts with anions which do not interfere with the phosphating process.
- Suitable salts are, for example, acetate, sulfate, phosphate, carbonate and / or fluoborate.
- Particularly suitable salts are those whose anion is present in the phosphating solution anyway, that is to say aluminum phosphate or aluminum salts of an anion which simultaneously acts as an oxidizing accelerator. Chlorides, chromates and / or arsenates should be avoided if possible.
- a preferred embodiment of the invention therefore provides for the metal surfaces to be brought into contact with a phosphating solution which contains aluminum ions in a minimum amount of 0.1 g / l.
- a further advantageous embodiment of the invention therefore provides for the metal surfaces to be brought into contact with a phosphating solution which contains aluminum ions in a maximum amount of 0.2 g / l.
- the phosphating solution based on zinc phosphate can contain the components other than aluminum ions in customary amounts.
- a particularly effective layer thickness setting can be achieved if, in a further development of the invention, the metal surfaces are brought into contact with a phosphating solution, the zinc ions in an amount of 4 to 20 g / l, preferably 8 to 13 g / l, phosphate ions in an amount of 5 to 25 g / l, preferably 9 to 15 g / l, and an oxidizing accelerator.
- Nitrate is preferred as the oxidizing accelerator.
- the metal surfaces are expediently covered with a phos brought into contact phatizing solution, the content of free acid is 4 to 10 points, preferably 6 to 7.5 points, and in total acid 20 to 40 points, preferably 28 to 31 points.
- the content of free acid points corresponds to the consumption of ml n / 10 NaOH when titrating a 10 ml bath sample against dimethyl yellow as an indicator.
- the total acid point content is equal to the consumption of ml n / 10 NaOH if a 10 ml bath sample is titrated against phenolphthalein as an indicator.
- the phosphating solution can have further additives which are generally used in phosphating processes. For example, nitrite and / or chlorate or other oxidizing agents having the same effect can be added in order to prevent the increase in the iron content entirely or beyond a certain value.
- the phosphating solutions can also contain small amounts of nickel or other metal ions. Typical nickel concentrations are 0.005 to 0.1 g / l, preferably 0.01 to 0.03 g / l.
- the phosphating solution can be prepared by dissolving the individual bath components separately. However, it can also be obtained from a concentrate.
- the phosphating solution does not contain layer weight regulators other than aluminum ions, e.g. Citrate or tartrate.
- the metal surfaces to be phosphated can be brought into contact with the phosphating solution in any way.
- Particularly suitable methods are immersion or spraying or combined immersion / spray treatment.
- the phosphating solution can be used within a wide temperature range, basically from ambient temperature to just below the boiling point. According to a preferred embodiment of the invention, the Metal surfaces in contact with a phosphating solution at a temperature in the range of 50 to 80 ° C.
- the process is carried out in such a way that the resulting layer weight is in the range from 1 to 1.6 g / m 2 .
- the metal surfaces provided with a phosphate layer can be washed with water and - if desired - with a rinse solution, e.g. a solution containing CrVI or CrIII / CrVI ions. After a possibly final rinsing of water, the metal surfaces are dried.
- a rinse solution e.g. a solution containing CrVI or CrIII / CrVI ions.
- the phosphating solution is usually supplemented during use.
- the addition can be made automatically, e.g. Depending on the metal surface being penetrated, it is necessary to ensure that the aluminum ion concentration is as constant as possible through regular analyzes. This can be done in a simple manner by measuring the layer weight. Fluctuations in the layer weight indicate a change in the aluminum ion concentration. For example, increasing layer weight indicates a decrease in the aluminum ion concentration and falling layer weight indicates an overdose of aluminum ions. After some orientation tests, it is possible to regulate the aluminum ion concentration solely via the layer weight. The determination of the content of aluminum ions by atomic absorption measurement or similar measuring methods and addition of aluminum ions depending on the measured value is preferred.
- the metal surfaces to be treated by the process according to the invention are generally iron or steel surfaces. However, other metal surfaces, in particular made of zinc or zinc alloys, can also be treated.
- the metal surfaces pretreated according to the invention are then subjected to an electrocoat, in particular a cathodic electrocoat.
- a phosphating solution was prepared that contained and the different, in the range of 0.1 to 0.2 g / 1 amounts of aluminum ions were added.
- the total score of the phosphating solution was 30, the free acid score was between 6 and 7.5.
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Abstract
Description
Die Erfindung betrifft ein Verfahren zur Vorbehandlung von Metalloberflächen für die Elektrotauchlackierung durch Aufbringen von Phosphatschichten mittels Phosphatierungslösungen auf Basis Zinkphosphat.The invention relates to a method for pretreating metal surfaces for electrocoating by applying phosphate layers by means of phosphating solutions based on zinc phosphate.
Es ist üblich, Metalloberflächen mit einer Phosphatschicht zu versehen, indem man sie mit sauren Zinkphosphatlösungen in Berührung bringt. Die erzeugten Phosphatüberzüge verbessern den Korrosionswiderstand der Metalloberfläche und die Haftung des anschließend aufgebrachten Lacküberzuges.It is common to provide a phosphate layer on metal surfaces by contacting them with acidic zinc phosphate solutions. The phosphate coatings produced improve the corrosion resistance of the metal surface and the adhesion of the lacquer coating applied subsequently.
Die wesentlichen Bestandteile saurer Zinkphosphatlösungen sind Zink- und Phosphationen sowie im allgemeinen ein oder mehrere oxidierende Beschleuniger. Es ist bekannt, daß man das Schichtgewicht und die Schichtbeschaffenheit verändern kann, wenn der Phosphatierungslösung weitere Substanzen zugesetzt werden. Beispielsweise ist es aus der GB-PS 866 377 bekannt, Tartrationen bei Spritzverfahren zuzugeben, damit eine dichte Phosphatschicht von geringerem Gewicht entsteht, als es bei Abwesenheit von Tartrat der Fall wäre.The essential components of acidic zinc phosphate solutions are zinc and phosphate ions and generally one or more oxidizing accelerators. It is known that the layer weight and the layer quality can be changed if further substances are added to the phosphating solution. For example, it is known from GB-PS 866 377 to add tartrations in the spraying process so that a dense phosphate layer of lighter weight is produced than would be the case in the absence of tartrate.
In jüngerer Zeit hat die Abscheidung von Lack nach dem Verfahren der Elektrotauchlackierung, insbesondere der kathodischen Elektrotauchlackierung, zunehmend an Bedeutung gewonnen. Hierbei tritt insofern ein besonderes Problem auf, als sich Phosphatschichten, die nach herkömmlichen Verfahren erzeugt werden, während der Elektrotauchlackierung von der Metalloberfläche lösen, in den Lackfilm übergehen und diesen nachteilig beeinflussen.More recently, the deposition of varnish using the electrodeposition process, especially the cathodic one Electrocoating, increasingly important. Here, a particular problem arises in that phosphate layers, which are produced by conventional methods, detach from the metal surface during electrocoating, pass into the paint film and adversely affect it.
Ein weiterer Schritt vorwärts bestand in der Erkenntnis, daß für die anschließende Elektrotauchlackierung dünne, feinkristalline Schichten erwünscht sind. Die unter Verwendung von Phosphatierungslösungen mit Zusätzen von Zitrat und Tartrat erzeugten Phosphatschichten hatten zwar die vorgenannten Eigenschaften, erwiesen sich jedoch infolge geringer Haftvermittlung dann als nachteilig, wenn die lackierten Artikel einer Kaltverformung unterworfen werden sollten. Diese Feststellung führte zu der Annahme, daß die Aufbringung von Lack durch die Methode der kathodischen Tauchlackierung ein ungeeigneter Weg ist, wenn hohe Lackhaftung bei der Kaltverformung erwünscht ist, und daß in Fällen einer beabsichtigten Kaltverformung Lacke auf Basis organischer Lösungsmittel einzusetzen sind bzw. die anodische Elektrotauchlackierung als Lackierverfahren einzusetzen ist.A further step forward was the realization that thin, finely crystalline layers are desired for the subsequent electrocoating. Although the phosphate layers produced using phosphating solutions with additions of citrate and tartrate had the abovementioned properties, they proved to be disadvantageous due to the poor adhesion, if the coated articles were to be subjected to cold deformation. This finding led to the assumption that the application of paint by the method of cathodic dip painting is an unsuitable way when high paint adhesion is desired during cold working, and that in cases of intended cold working, paints based on organic solvents should be used or the anodic one Electrocoating is to be used as the painting process.
Die weitere Entwicklung in der Phosphatierungstechnik ging in die Richtung der sogenannten "Niedrig-Zink-Verfahren . Sie bedienen sich Phosphatierungslösungen, in denen der Zinkgehalt niedriger als bei herkömmlichen Phosphatierungslösungen ist, d.h. in denen das Verhältnis von Zn : P04 im Bereich von 1 : (12 bis 110) liegt (DE-PS 22 32 067, GB-PS 20 93 075).The further development in phosphating technology went in the direction of the so-called "low-zinc processes. They use phosphating solutions in which the zinc content is lower than in conventional phosphating solutions, ie in which the ratio of Zn: P0 4 in the range of 1: (12 to 110) is (DE-PS 22 32 067, GB-PS 20 93 075).
Obgleich diese Verfahren eine beträchtliche Verbreitung gefunden haben, kann deren Uberwachung infolge der geringen Zinkgehalte der Phosphatierungslösungen mitunter Schwierigkeiten bereiten.Although these methods have found widespread use, monitoring them can be difficult due to the low zinc content of the phosphating solutions.
Aufgabe der Erfindung ist es, ein Verfahren zur Vorbehandlung von Metalloberflächen für die Elektrotauchlackierung bereitzustellen, das die Nachteile oder Schwierigkeiten der bekannten Verfahren vermeidet und in der Lage ist, Phosphatschichten zu erzeugen, auf denen nach Verfahren der Elektrotauchlackierung abgeschiedene Lacke, selbst unter den Beanspruchungen der Kaltverformung, fest haften.The object of the invention is to provide a method for pretreating metal surfaces for electrocoating set, which avoids the disadvantages or difficulties of the known methods and is able to produce phosphate layers on which deposited by methods of electrocoating, even under the strain of cold forming, firmly adheres.
Die Aufgabe wird gelöst, indem das Verfahren der eingangs genannten Art entsprechend der Erfindung derart ausgestaltet wird, daß man die Metalloberflächen mit einer Phosphatierungslösung in Berührung bringt, die Aluminiumionen in einer Menge von 0,05 bis 0,4 g/1 enthält, und in der das Gewichtsverhältnis von Aluminium zu Zink 1 : 50 bis 1 : 100 beträgt.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 metal surfaces are brought into contact with a phosphating solution which contains aluminum ions in an amount of 0.05 to 0.4 g / l, and in which is the weight ratio of aluminum to zinc 1:50 to 1: 100.
Die hervorragende Haftvermittlung der erfindungsgemäß erzeugten Phosphatschichten gegenüber Lackfilmen, die nach dem Verfahren der Elektrotauchlackierung, insbesondere der kathodischen Elektrotauchlackierung, erzeugt worden sind, zeigt sich insbesondere bei den Haftungstests entsprechend der Erichsen-Tiefung und dem Biegetest.The excellent adhesion of the P inventively produced hosphatschichten compared with paint films which have been produced by the process of electrocoating, especially the cathodic electrocoating, is particularly evident in the adhesion tests according to the Erichsen cupping test and the bending test.
Zwar ist es aus der GB-PS 943 169 bekannt, Phosphatierungslösungen auf Basis Zinkphosphat Aluminiumionen zuzugeben, um dadurch das Gewicht der Phosphatschicht zu reduzieren und die Lackhaftung zu verbessern. Jedoch bezieht sich das bekannte Verfahren auf die Vorbehandlung von Metalloberflächen für die Aufbringung der damals gebräuchlichen Lacke, also_solcher, die insbesondere nach mechanischen Verfahren appliziert werden. Die besonderen, mit der Elektrotauchlackierung verbundenen Probleme waren nicht existent. Darüber hinaus ist das seinerzeit für notwendig erachtete Verhältnis von Aluminium zu Zink von dem für das erfindungsgemäße Verfahren als vorteilhaft erachteten Verhältnis verschieden.Although it is known from GB 943 169 Patent to admit phosphating solutions based on zinc phosphate aluminum ions, thereby to reduce the weight of the phosphate layer and the L ackhaftung to improve. However, the known method relates to the pretreatment of metal surfaces for the application of the lacquers customary at that time, that is to say those which are applied in particular by mechanical methods. The particular problems associated with electrocoating did not exist. In addition, the ratio of aluminum to zinc which was considered necessary at the time is different from the ratio which is considered advantageous for the process according to the invention.
Der erforderliche Aluminiumgehalt der Phosphatierungslösung wird eingestellt; indem man das Aluminium in Form einer in wäßriger, saurer Lösung löslichen Verbindung einbringt. Geeignete Einbringungsformen sind Aluminiumhydroxid oder Aluminiumsalze mit Anionen, die den Phosphatiervorgang nicht stören. Geeignete Salze sind z.B. Acetat, Sulfat, Phosphat, Carbonat und/oder Fluoborat. Besonders geeignete Salze sind solche, deren Anion ohnehin in der Phosphatierungslösung vorhanden sind, also Aluminiumphosphat oder Aluminiumsalze eines Anions, das gleichzeitig als oxidierender Beschleuniger wirkt. Nach Möglichkeit vermieden werden sollten Chloride, Chromate und/oder Arsenate.The required aluminum content of the phosphating solution is set; by introducing the aluminum in the form of a compound which is soluble in aqueous, acidic solution. Suitable forms of incorporation are aluminum hydroxide or aluminum salts with anions which do not interfere with the phosphating process. Suitable salts are, for example, acetate, sulfate, phosphate, carbonate and / or fluoborate. Particularly suitable salts are those whose anion is present in the phosphating solution anyway, that is to say aluminum phosphate or aluminum salts of an anion which simultaneously acts as an oxidizing accelerator. Chlorides, chromates and / or arsenates should be avoided if possible.
Wenn der Aluminiumgehalt zu niedrig liegt, erscheinen in der Phosphatschicht vergleichsweise grobkörnige Bereiche. Eine bevorzugte Ausgestaltung der Erfindung sieht deshalb vor, die Metalloberflächen mit einer Phosphatierungslösung in Berührung zu bringen, die Aluminiumionen in einer Mindestmenge von 0,1 g/1 enthält.If the aluminum content is too low, comparatively coarse-grained areas appear in the phosphate layer. A preferred embodiment of the invention therefore provides for the metal surfaces to be brought into contact with a phosphating solution which contains aluminum ions in a minimum amount of 0.1 g / l.
Liegt der Gehalt an Aluminiumionen zu hoch, kann das Schichtgewicht zu weit reduziert werden. Eine weitere vorteilhafte Ausgestaltung der Erfindung sieht daher vor, die Metalloberflächen mit einer Phosphatierungslösung in Berührung zu bringen, die Aluminiumionen in einer Höchstmenge von 0,2 g/1 enthält.If the aluminum ion content is too high, the layer weight can be reduced too much. A further advantageous embodiment of the invention therefore provides for the metal surfaces to be brought into contact with a phosphating solution which contains aluminum ions in a maximum amount of 0.2 g / l.
Die Phosphatierungslösung auf Basis Zinkphosphat kann die von Aluminiumionen verschiedenen Komponenten in üblichen Mengen enthalten. Eine besonders wirksame Schichtdickeneinstellung ist erreichbar, wenn in Weiterbildung der Erfindung die Metalloberflächen mit einer Phosphatierungslösung in Berührung gebracht werden, die Zinkionen in einer Menge von 4 bis 20 g/l, vorzugsweise 8 bis 13 g/l, Phosphationen in einer Menge von 5 bis 25 g/l, vorzugsweise 9 bis 15 g/l, sowie einen oxidierenden Beschleuniger enthalten. Als oxidierender Beschleuniger ist Nitrat bevorzugt.The phosphating solution based on zinc phosphate can contain the components other than aluminum ions in customary amounts. A particularly effective layer thickness setting can be achieved if, in a further development of the invention, the metal surfaces are brought into contact with a phosphating solution, the zinc ions in an amount of 4 to 20 g / l, preferably 8 to 13 g / l, phosphate ions in an amount of 5 to 25 g / l, preferably 9 to 15 g / l, and an oxidizing accelerator. Nitrate is preferred as the oxidizing accelerator.
Zweckmäßigerweise werden die Metalloberflächen mit einer Phosphatierungslösung in Berührung gebracht, deren Gehalt an Freier Säure 4 bis 10 Punkte, vorzugsweise 6 bis 7,5 Punkte, und an Gesamtsäure 20 bis 40 Punkte, vorzugsweise 28 bis 31 Punkte, beträgt. Der Gehalt an Punkten Freier Säure entspricht dem Verbrauch an ml n/10 NaOH bei Titration einer 10 ml-Badprobe gegen Dimethylgelb als Indikator. Der Gehalt an Gesamtsäurepunkten ist gleich dem Verbrauch an ml n/10 NaOH, wenn eine 10 ml-Badprobe gegen Phenolphthalein als Indikator titriert wird.The metal surfaces are expediently covered with a phos brought into contact phatizing solution, the content of free acid is 4 to 10 points, preferably 6 to 7.5 points, and in total acid 20 to 40 points, preferably 28 to 31 points. The content of free acid points corresponds to the consumption of ml n / 10 NaOH when titrating a 10 ml bath sample against dimethyl yellow as an indicator. The total acid point content is equal to the consumption of ml n / 10 NaOH if a 10 ml bath sample is titrated against phenolphthalein as an indicator.
Die Phosphatierungslösung kann weitere, bei Phosphatierverfahren generell gebräuchliche Zusätze aufweisen. Beispielsweise können Nitrit und/oder Chlorat oder andere gleichwirkende Oxidationsmittel zugegeben werden, um den Anstieg des Eisengehaltes ganz oder über einen bestimmten Wert hinaus zu verhindern. Auch können die Phosphatierungslösungen geringe Mengen an Nickel- oder anderen Metallionen enthalten. Typische Nickelkonzentrationen betragen 0,005 bis 0,1 g/l, vorzugsweise 0,01 bis 0,03 g/l.The phosphating solution can have further additives which are generally used in phosphating processes. For example, nitrite and / or chlorate or other oxidizing agents having the same effect can be added in order to prevent the increase in the iron content entirely or beyond a certain value. The phosphating solutions can also contain small amounts of nickel or other metal ions. Typical nickel concentrations are 0.005 to 0.1 g / l, preferably 0.01 to 0.03 g / l.
Die Phosphatierungslösung kann hergestellt werden, indem man die einzelnen Badbestandteile gesondert auflöst. Sie kann jedoch auch aus einem Konzentrat gewonnen werden.The phosphating solution can be prepared by dissolving the individual bath components separately. However, it can also be obtained from a concentrate.
Im allgemeinen enthält die Phosphatierungslösung keine von Aluminiumionen verschiedenen Schichtgewichtsregulatoren, wie z.B. Zitrat oder Tartrat.In general, the phosphating solution does not contain layer weight regulators other than aluminum ions, e.g. Citrate or tartrate.
Die zu phosphatierenden Metalloberflächen können auf jede beliebige Weise mit der Phosphatierungslösung in Berührung gebracht werden. Besonders geeignete Verfahren sind Tauchen oder Spritzen bzw. kombinierte Tauch-/Spritzbehandlung.The metal surfaces to be phosphated can be brought into contact with the phosphating solution in any way. Particularly suitable methods are immersion or spraying or combined immersion / spray treatment.
Die Phosphatierungslösung kann innerhalb eines weiten Temperaturbereiches, grundsätzlich von Umgebungstemperatur bis knapp unterhalb des Siedepunktes, zur Anwendung kommen. Gemäß einer bevorzugten Ausführungsform der Erfindung bringt man die Metalloberflächen mit einer Phosphatierungslösung bei einer Temperatur im Bereich von 50 bis 80 °C in Berührung.The phosphating solution can be used within a wide temperature range, basically from ambient temperature to just below the boiling point. According to a preferred embodiment of the invention, the Metal surfaces in contact with a phosphating solution at a temperature in the range of 50 to 80 ° C.
Unter Berücksichtigung der Verfahrensparameter, des Aluminiumgehaltes der Phosphatierungslösung, des Aluminium/Zink-Verhältnisses, des Zink- und Phosphatgehaltes der Punktzahl und der Behandlungstemperatur wird gemäß einer weiteren vorteilhaften Ausführungsform das Verfahren derart geführt, daß das resultierende Schichtgewicht im Bereich von 1 bis 1,6 g/m2 liegt.Taking into account the process parameters, the aluminum content of the phosphating solution, the aluminum / zinc ratio, the zinc and phosphate content of the number of points and the treatment temperature, according to a further advantageous embodiment the process is carried out in such a way that the resulting layer weight is in the range from 1 to 1.6 g / m 2 .
Die mit einer Phosphatschicht versehenen Metalloberflächen können mit Wasser und - falls erwünscht - mit einer Nachspüllösung, z.B. einer CrVI- oder CrIII/CrVI-ionen enthaltenden Lösung, nachbehandelt werden. Nach einer gegebenenfalls abschließenden Wasserspülung werden die Metalloberflächen getrocknet.The metal surfaces provided with a phosphate layer can be washed with water and - if desired - with a rinse solution, e.g. a solution containing CrVI or CrIII / CrVI ions. After a possibly final rinsing of water, the metal surfaces are dried.
Üblicherweise wird die Phosphatierungslösung während ihres Gebrauchs ergänzt. Obgleich die Ergänzung automatisch vorgenommen werden kann, z.B. in Abhängigkeit von der durchgesetzten Metalloberfläche, ist es erforderlich, durch regelmäßig vorzunehmende Analysen eine möglichst konstante Aluminiumionenkonzentration sicherzustellen. Dies kann in einfacher Weise durch Messung des Schichtgewichtes erfolgen. Schwankungen im Schichtgewicht deuten auf eine Veränderung der Aluminiumionenkonzentration. Beispielsweise deutet steigendes Schichtgewicht auf eine Abnahme der Aluminiumionenkonzentration und fallendes Schichtgewicht auf eine Überdosierung an Aluminiumionen. Nach einigen orientierenden Tests ist es möglich, die Aluminiumionenkonzentration allein über das Schichtgewicht zu regeln. Der Ermittlung des Gehaltes an Aluminiumionen durch Atomabsorptionsmessung oder ähnliche Meßverfahren und Zugabe von Aluminiumionen in Abhängigkeit vom Meßwert wird jedoch der Vorzug gegeben.The phosphating solution is usually supplemented during use. Although the addition can be made automatically, e.g. Depending on the metal surface being penetrated, it is necessary to ensure that the aluminum ion concentration is as constant as possible through regular analyzes. This can be done in a simple manner by measuring the layer weight. Fluctuations in the layer weight indicate a change in the aluminum ion concentration. For example, increasing layer weight indicates a decrease in the aluminum ion concentration and falling layer weight indicates an overdose of aluminum ions. After some orientation tests, it is possible to regulate the aluminum ion concentration solely via the layer weight. The determination of the content of aluminum ions by atomic absorption measurement or similar measuring methods and addition of aluminum ions depending on the measured value is preferred.
Die nach dem erfindungsgemäßen Verfahren zu behandelnden Metalloberflächen sind im allgemeinen Eisen- oder Stahloberflächen. Es können jedoch andere auch Metalloberflächen, insbesondere aus Zink- oder Zinklegierungen, behandelt werden.The metal surfaces to be treated by the process according to the invention are generally iron or steel surfaces. However, other metal surfaces, in particular made of zinc or zinc alloys, can also be treated.
Die erfindungsgemäß vorbehandelten Metalloberflächen werden anschließend einer Elektrotauchlackierung, insbesondere einer kathodischen Elektrotauchlackierung, unterworfen.The metal surfaces pretreated according to the invention are then subjected to an electrocoat, in particular a cathodic electrocoat.
Die Erfindung wird anhand des nachfolgenden Beispiels beispielsweise und näher erläutert.The invention is illustrated by way of example and in more detail using the example below.
Es wurde eine Phosphatierungslösung hergestellt, die
Zuvor gereinigte Stahlbleche wurden mit den vorgenannten Phosphatierungslösungen durch 10 min lange Tauchbehandlung bei 80 °C in Berührung gebracht. Während der Benutzung der Phosphatierungslösung wurde durch Zugabe von Natriumnitrit oder Natriumchlorat die Eisen-II-ionen-Anreicherung verhindert. Bei Verwendung von Natriumnitrit lag die maximale Menge bei 0,5 g/l, bei Verwendung von Natriumchlorat bei maximal 1,5 g/l.Previously cleaned steel sheets were brought into contact with the aforementioned phosphating solutions by immersion treatment at 80 ° C. for 10 minutes. During the use of the phosphating solution, the addition of sodium nitrite or sodium chlorate prevented the iron II ion accumulation. When using sodium nitrite the maximum amount was 0.5 g / l, when using sodium chlorate it was a maximum of 1.5 g / l.
Es wurden folgende Ergebnisse erzielt:
Die vorgenannten Stahlbleche ließen sich sämtlich durch konventionelle Verfahren der Elektrotauchlackierung einwandfrei beschichten. Außerdem wurde eine ausgezeichnete Lackhaftung, bei Biegetests ermittelt, erzielt.The aforementioned steel sheets could all be coated perfectly using conventional electrocoating processes. Excellent paint adhesion, determined in bending tests, was also achieved.
Claims (7)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8231321 | 1982-11-02 | ||
| GB8231321 | 1982-11-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0109110A1 true EP0109110A1 (en) | 1984-05-23 |
Family
ID=10533998
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP83201504A Withdrawn EP0109110A1 (en) | 1982-11-02 | 1983-10-20 | Process for preparing metallic surfaces for electropainting |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0109110A1 (en) |
| DE (1) | DE3337794A1 (en) |
| ES (1) | ES526801A0 (en) |
| PT (1) | PT77585B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1743955A3 (en) * | 2005-07-15 | 2007-01-24 | NHK Spring Co., Ltd. | Steel product excellent in corrosion resistance and corrosion fatigue resistance, and surface treatment method therefor |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2316810A (en) * | 1940-04-10 | 1943-04-20 | American Chemical Paiant Compa | Method of and material for coating metal surfaces with water insoluble metallic phosphates |
| FR1300295A (en) * | 1961-06-22 | 1962-08-03 | Parker Ste Continentale | Phosphating process for rubbing metal surfaces |
| GB943169A (en) * | 1961-03-23 | 1963-12-04 | Pyrene Co Ltd | Improvements relating to the phosphate-coating of metals |
| FR2186547A1 (en) * | 1972-04-27 | 1974-01-11 | Parker Ste Continentale | Phosphating bath - based on alkali phosphates and contg minor addns of certain metal ions |
| FR2219245A1 (en) * | 1973-02-27 | 1974-09-20 | Parker Ste Continentale |
-
1983
- 1983-10-18 DE DE19833337794 patent/DE3337794A1/en not_active Withdrawn
- 1983-10-20 EP EP83201504A patent/EP0109110A1/en not_active Withdrawn
- 1983-10-27 ES ES526801A patent/ES526801A0/en active Granted
- 1983-10-28 PT PT7758583A patent/PT77585B/en unknown
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2316810A (en) * | 1940-04-10 | 1943-04-20 | American Chemical Paiant Compa | Method of and material for coating metal surfaces with water insoluble metallic phosphates |
| GB943169A (en) * | 1961-03-23 | 1963-12-04 | Pyrene Co Ltd | Improvements relating to the phosphate-coating of metals |
| FR1300295A (en) * | 1961-06-22 | 1962-08-03 | Parker Ste Continentale | Phosphating process for rubbing metal surfaces |
| FR2186547A1 (en) * | 1972-04-27 | 1974-01-11 | Parker Ste Continentale | Phosphating bath - based on alkali phosphates and contg minor addns of certain metal ions |
| FR2219245A1 (en) * | 1973-02-27 | 1974-09-20 | Parker Ste Continentale |
Non-Patent Citations (2)
| Title |
|---|
| CHEMICAL ABSTRACTS, Band 80, Nr. 26, 1 Juli 1974, page 42, Nr. 147054f, Columbus, Ohio, US * |
| CHEMICAL ABSTRACTS, Band 80, Nr. 26, 1 Juli 1974, page 42, Nr. 147054f, Columbus, Ohio, US; & JP-A-48 034 655 (DAINIPPON PAINT MFG. CO. LTD.) 23-10-1973 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1743955A3 (en) * | 2005-07-15 | 2007-01-24 | NHK Spring Co., Ltd. | Steel product excellent in corrosion resistance and corrosion fatigue resistance, and surface treatment method therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| PT77585A (en) | 1983-11-01 |
| DE3337794A1 (en) | 1984-05-03 |
| ES8407107A1 (en) | 1984-09-01 |
| ES526801A0 (en) | 1984-09-01 |
| PT77585B (en) | 1986-03-18 |
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Legal Events
| Date | Code | Title | Description |
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| 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 |
Designated state(s): AT BE CH DE FR IT LI NL SE |
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| 17P | Request for examination filed |
Effective date: 19840911 |
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| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
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| 18W | Application withdrawn |
Withdrawal date: 19851105 |
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| RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: HIGGINS, GEORGE LEONARD |