EP2157213A1 - Anti-corrosion coating with two zinc layers - Google Patents
Anti-corrosion coating with two zinc layers Download PDFInfo
- Publication number
- EP2157213A1 EP2157213A1 EP08014206A EP08014206A EP2157213A1 EP 2157213 A1 EP2157213 A1 EP 2157213A1 EP 08014206 A EP08014206 A EP 08014206A EP 08014206 A EP08014206 A EP 08014206A EP 2157213 A1 EP2157213 A1 EP 2157213A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- bath
- zinc
- zinc layer
- acid
- thickness
- 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.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/60—Electroplating characterised by the structure or texture of the layers
- C25D5/625—Discontinuous layers, e.g. microcracked layers
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/22—Electroplating: Baths therefor from solutions of zinc
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/10—Electroplating with more than one layer of the same or of different metals
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/60—Electroplating characterised by the structure or texture of the layers
- C25D5/615—Microstructure of the layers, e.g. mixed structure
- C25D5/617—Crystalline layers
Definitions
- the invention relates to a corrosion protection coating with zinc.
- Zinc layers as corrosion protection of metallic objects are well known in the art, as well as methods for depositing such a zinc layer from a galvanic bath.
- the invention is based on the problem of specifying an improved corrosion protection coating.
- the invention solves the problem with a process for anticorrosive coating in which a first zinc layer with a thickness of at least 4 microns in an acidic plating bath and immediately on the first a second zinc layer is deposited with a thickness of at least 5 microns in an alkaline galvanic bath ,
- the invention is directed to an article that can be produced in this way.
- the invention is based on the idea to improve the corrosion protection with a well-adhering and durable zinc coating by directly two successive zinc layers of an acidic and an alkaline galvanic bath each of at least a certain thickness are deposited.
- the anticorrosion coating according to the invention has two directly successive zinc layers, of which the first zinc layer is deposited from an aqueous acidic and the second zinc layer from an aqueous alkaline galvanic bath.
- These two galvanic bath types for the deposition of zinc layers are known in principle from the prior art, the invention being significantly in the specified combination and thickness of the layers deposited from each different baths.
- the zinc layer deposited from an aqueous acidic bath has a very good surface adhesion, in particular also on steel, at least in comparison with the layer deposited from an alkaline bath, but may show a cracked, columnar surface.
- a zinc layer deposited from an alkaline bath has a quasi-amorphous closed surface of comparatively high hardness but lower ductility, which can be torn comparatively easily under mechanical stress or else detached from the coated material. Only through the combination according to the invention of the first zinc layer with the immediately following second zinc layer can a significantly improved corrosion protection be achieved in the layer thicknesses according to the invention.
- the first (ductile) zinc layer in particular ensures a very good adhesion to the coated article, can absorb mechanical compression or strain and serves as a primer for the second zinc layer, which has a closed surface of the entire coating of larger Hardship creates.
- the thickness of the first zinc layer is at least 4 .mu.m, 5 .mu.m or 6 .mu.m and the thickness of the second zinc layer in this order is increasingly preferably at least 5 .mu.m, 7 .mu.m, 9 .mu.m or 10 .mu.m.
- the layer thickness of the first zinc layer can be increasingly preferred in this order at most 15 microns, 12 microns, 10 microns or 8 microns and the thickness of the second zinc layer in this order increasingly preferably be at most 25 microns, 22 microns, 20 microns or 18 microns.
- the aqueous acid plating bath preferably has a pH of in these orders increasingly preferably at least 4.5, 4.8 or 4.9 and at most 5.8, 5.5 or 5.3.
- the aqueous alkaline galvanic bath preferably has a pH of at least 12 and at most 14, with a pH above 13 being particularly preferred here.
- the galvanic treatment time for depositing the first zinc layer may be in these sequences increasingly preferably at least 4 min, 6 min, 8 min or 10 min and at most 30 min, 27 min, 24 min or 20 min.
- a bath temperature of at least 12 ° C or 20 ° C and at most 35 ° C or 30 ° C is preferred.
- the treatment time for depositing the second zinc layer from the alkaline bath may be increasingly preferably at least 15 minutes, 18 minutes or 20 minutes and at most 45 minutes, 42 minutes or 40 minutes in these orders.
- the alkaline bath preferably has a temperature of at least 15 ° C or 20 ° C and at most 40 ° C or 30 ° C.
- the current density in the electrodeposition of the first zinc layer in the acid bath is preferably at least 0.3 A / dm 2 and at most 2.5 A / dm 2 , preferably at a voltage between 1.5 V and 5 V.
- the current density in the alkaline bath is preferably at least 0.5 A / dm 2 and at most 5 A / dm 2 , preferably at a voltage of at least 3 V and at most 8 V.
- the acid plating bath is preferably increasingly preferred in these orders at least 10 g / l, 20 g / l, 25 g / l or 30 g / l and at most 60 g / l, 45 g / l or 40 g / l zinc, at least 80 g / l, 100 g / l or 120 g / l and not more than 200 g / l, 180 g / l or 160 g / l chloride and at least 10 g / l, 15 g / l, 20 g / l or 25 g / l and at most 40 g / l or 35 g / l boric acid.
- the acid plating bath may additionally be increasingly preferred in the respective orders at least 0.5 ml / l or 0.8 ml / l and not more than 2 ml / l or 1.5 ml / l organic brightener additive and / or at least 30 ml / l and not more than 80 ml / l or 50 ml / l of organic surfactants.
- the acidic bath may be an aqueous solution which, with particular preference to all possible impurities, has exclusively the abovementioned components.
- the alkaline plating bath may be increasingly preferred in these orders at least 5 g / l or 10 g / l and not more than 20 g / l or 14 g / l zinc, at least 50 g / l or 100 g / l and at most 200 g / l or 140 g / l of an alkaline additive, wherein the alkaline additive may be, for example, NaOH.
- the alkaline bath in these orders may be increasingly preferred in addition at least 8 ml / l or 10 ml / l and not more than 20 ml / l or 15 ml / l of an organic luster carrier and / or at least 0.5 ml / l and at most 3 ml / l or 2 ml / l of an organic gloss enhancer.
- the alkaline galvanic bath is preferably in the form of an aqueous solution and, in a particularly preferred embodiment, may contain, in addition to possible impurities, at most the abovementioned components in aqueous solution.
- the object to be coated is rinsed, conveniently at least with water.
- rinsing can take place after the deposition of the second galvanic zinc layer.
- a cleaning of the article to be coated prior to the deposition of the first zinc layer is advantageous, in which case, in particular, depending on the material of the article to be coated, from the prior art, numerous cleaning methods are known.
- the galvanic bath and / or also the object to be coated can be moved in the bath.
- a thick-layer passivation can follow (in particular directly) onto the second zinc layer, wherein it can be applied in a further process in a chemical bath in a further bath.
- Such an additional thick-film passivation can additionally increase the mechanical resistance of the entire coating.
- an additional protection against chemical influences can be achieved.
- a lacquer can also be applied directly to the second zinc layer or also directly following the thick-layer passivation.
- the mechanical resistance and / or the protection against chemical influences can likewise be improved in a known manner.
- the paint can be applied by electrochemical dip coating, preferably by cathodic dip coating, which is also referred to as KTL coating and is known from the prior art.
- An article which has at least the two galvanic zinc layers according to the invention can be used as a component of a motor vehicle, particularly preferably as a component that is freely accessible from below the vehicle. It may be a vehicle part made of stainless steel and be protected according to the invention from moisture, corrosive substances such as salt, but also mechanical effects on its surface. Particularly preferred may be a component of a motor vehicle floor, in particular a part of a drive system or a suspension, for example a subframe, have a coating according to the invention.
- a subframe made of a non-stainless steel sheet is cleaned in a first treatment, in particular degreased and freed from surface oxides. After rinsing in water, it is galvanized in an acid plating bath at 28 ° C with a current of 0.6 A / dm 2 under a voltage of 2.7 V at a treatment time of 15 min.
- the bath with a pH of 5.0 consists here of an aqueous solution of 35 g / l zinc, 140 g / l chloride, 30 g / l boric acid, 1.2 ml / l organic brightener and 40 ml / l organic surfactants.
- a first ductile well-adhering zinc layer of surface-cracked structure of about 7 microns is applied and then rinsed the steering column in water.
- a further galvanic treatment takes place in an alkaline bath with a pH of about 14 and at a temperature of 26 ° C.
- a second zinc layer is deposited during a treatment period of 30 minutes at a current density of 1 A / dm 2 at an applied voltage of 5.5 V.
- This second galvanic bath in this case has an aqueous solution of 12 g / l zinc, 120 g / l NaOH, 12 ml / l organic gloss and 1.2 ml / l organic gloss enhancer on.
- a layer thickness of about 16 microns of a quasi-amorphous zinc structure is deposited here, wherein after the galvanic coating of the subframe is rinsed again with water.
- a thick film passivation is chemically deposited on a coated subframe in a further bath directly on the second zinc layer, and then the article is rinsed again in a water bath.
- the subframe produced in this way has a corrosion protection coating with two directly successive zinc layers and an outer thick-film passivation.
- Another embodiment resides in the anti-corrosion coating of a subframe which differs from that previously described by a cathodic dip-coating rather than the thick-film passivation.
- a fourth embodiment corresponds to the first, thus has two successive zinc layers according to the invention.
- a thick-film passivation is applied directly to the second zinc layer and directly to this one KTL coating.
- This embodiment thus has a corrosion protection coating with these four successive layers.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Electroplating Methods And Accessories (AREA)
- Electroplating And Plating Baths Therefor (AREA)
Abstract
Description
Die Erfindung betrifft eine Korrosionsschutzbeschichtung mit Zink.The invention relates to a corrosion protection coating with zinc.
Zinkschichten als Korrosionsschutz von metallischen Gegenständen sind nach dem Stand der Technik allgemein bekannt, ebenso Verfahren zum Abscheiden einer solchen Zinkschicht aus einem galvanischen Bad.Zinc layers as corrosion protection of metallic objects are well known in the art, as well as methods for depositing such a zinc layer from a galvanic bath.
Der Erfindung liegt das Problem zugrunde, eine verbesserte Korrosionsschutzbeschichtung anzugeben.The invention is based on the problem of specifying an improved corrosion protection coating.
Die Erfindung löst das Problem mit einem Verfahren zur Korrosionsschutzbeschichtung, bei dem eine ersten Zinkschicht mit einer Dicke von mindestens 4 µm in einem sauren galvanischen Bad und unmittelbar auf der ersten eine zweite Zinkschicht mit einer Dicke von mindestens 5 µm in einem alkalischen galvanischen Bad abgeschieden wird.The invention solves the problem with a process for anticorrosive coating in which a first zinc layer with a thickness of at least 4 microns in an acidic plating bath and immediately on the first a second zinc layer is deposited with a thickness of at least 5 microns in an alkaline galvanic bath ,
Ferner richtet sich die Erfindung auf einen so herstellbaren Gegenstand.Furthermore, the invention is directed to an article that can be produced in this way.
Bevorzugte Ausgestaltungen der Erfindung sind in den abhängigen Ansprüchen angegeben und ergeben sich des weiteren aus der folgenden Beschreibung. Die Offenbarung ist dabei im Hinblick auf die Verfahrens- und Vorrichtungskategorie, sowie auf die Verwendung eines Gegenstandes, der eine erfindungsgemäße Beschichtung aufweist oder nach dem erfindungsgemäßen Verfahren beschichtet wurde, zu verstehen.Preferred embodiments of the invention are set forth in the dependent claims and will be further apparent from the following description. The disclosure is to be understood with regard to the method and device category, as well as to the use of an article which has a coating according to the invention or has been coated by the process according to the invention.
Der Erfindung liegt die Idee zugrunde, mit einer gut haftenden und strapazierfähigen Zinkbeschichtung den Korrosionsschutz zu verbessern, indem direkt aufeinander folgend zwei Zinkschichten aus einem sauren und einem alkalischen galvanischen Bad jeweils von zumindest einer gewissen Dicke abgeschieden werden.The invention is based on the idea to improve the corrosion protection with a well-adhering and durable zinc coating by directly two successive zinc layers of an acidic and an alkaline galvanic bath each of at least a certain thickness are deposited.
Dabei kann eine solche Zinkbeschichtung dem Korrosionsschutz eines Gegenstandes mit metallischer Oberfläche, die vorzugsweise eisenhaltig, beispielsweise aus Stahl, ist, dienen.In this case, such a zinc coating corrosion protection of an article with a metallic surface, which is preferably ferrous, for example, steel serve.
Die erfindungsgemäße Korrosionsschutzbeschichtung weist zwei unmittelbar aufeinander folgende Zinkschichten auf, von denen die erste Zinkschicht aus einem wässrigen sauren und die zweite Zinkschicht aus einem wässrigen alkalischen galvanischen Bad abgeschieden wird. Diese beiden galvanischen Badtypen zur Abscheidung von Zinkschichten sind grundsätzlich aus dem Stand der Technik bekannt, wobei die Erfindung maßgeblich in der angegebenen Kombination und Dicke der Schichten, abgeschieden aus jeweils unterschiedlichen Bädern, liegt.The anticorrosion coating according to the invention has two directly successive zinc layers, of which the first zinc layer is deposited from an aqueous acidic and the second zinc layer from an aqueous alkaline galvanic bath. These two galvanic bath types for the deposition of zinc layers are known in principle from the prior art, the invention being significantly in the specified combination and thickness of the layers deposited from each different baths.
Die aus einem wässrigen sauren Bad abgeschiedene Zinkschicht weist zumindest im Vergleich zu der aus einem alkalischen Bad abgeschiedenen Schicht eine sehr gute Oberflächenhaftung, insbesondere auch auf Stahl auf, kann jedoch eine rissige, säulenartige Oberfläche zeigen. Dagegen weist eine aus einem alkalischen Bad abgeschiedene Zinkschicht eine quasiamorphe geschlossene Oberfläche von vergleichsweise hoher Härte jedoch geringerer Duktilität auf, die bei einer mechanischen Belastung vergleichsweise leicht aufreißen oder sich auch von dem beschichteten Material ablösen kann. Erst durch die erfindungsgemäße Kombination der ersten Zinkschicht mit der unmittelbar folgenden zweiten Zinkschicht kann bei den erfindungsgemäßen Schichtdicken ein deutlich verbesserter Korrosionsschutz erreicht werden. Dabei zeigt sich besonders deutlich ein Synergieeffekt, wobei die erste (duktile) Zinkschicht insbesondere eine sehr gute Haftung auf dem beschichteten Gegenstand gewährleistet, mechanische Stauchungen oder Dehnungen abfangen kann und als Haftvermittler für die zweite Zinkschicht dient, die eine geschlossene Oberfläche der gesamte Beschichtung von größerer Härte schafft.The zinc layer deposited from an aqueous acidic bath has a very good surface adhesion, in particular also on steel, at least in comparison with the layer deposited from an alkaline bath, but may show a cracked, columnar surface. In contrast, a zinc layer deposited from an alkaline bath has a quasi-amorphous closed surface of comparatively high hardness but lower ductility, which can be torn comparatively easily under mechanical stress or else detached from the coated material. Only through the combination according to the invention of the first zinc layer with the immediately following second zinc layer can a significantly improved corrosion protection be achieved in the layer thicknesses according to the invention. In this case, a synergy effect shows particularly clearly, wherein the first (ductile) zinc layer in particular ensures a very good adhesion to the coated article, can absorb mechanical compression or strain and serves as a primer for the second zinc layer, which has a closed surface of the entire coating of larger Hardship creates.
Dabei beträgt die Dicke der ersten Zinkschicht mindestens 4 µm, 5 µm oder 6 µm und die Dicke der zweiten Zinkschicht in dieser Reihenfolge zunehmend bevorzugt mindestens 5 µm, 7 µm, 9 µm oder 10 µm.The thickness of the first zinc layer is at least 4 .mu.m, 5 .mu.m or 6 .mu.m and the thickness of the second zinc layer in this order is increasingly preferably at least 5 .mu.m, 7 .mu.m, 9 .mu.m or 10 .mu.m.
Für einen hinreichenden Korrosionsschutz und gute Schichtmorphologie kann die Schichtdicke der ersten Zinkschicht in dieser Reihenfolge zunehmend bevorzugt höchstens 15 µm, 12 µm, 10 µm oder 8 µm und die Dicke der zweiten Zinkschicht in dieser Reihenfolge zunehmend bevorzugt höchstens 25 µm, 22 µm, 20 µm oder 18 µm sein.For sufficient corrosion protection and good layer morphology, the layer thickness of the first zinc layer can be increasingly preferred in this order at most 15 microns, 12 microns, 10 microns or 8 microns and the thickness of the second zinc layer in this order increasingly preferably be at most 25 microns, 22 microns, 20 microns or 18 microns.
Das wässrig saure galvanische Bad weist vorzugsweise einen pH-Wert von in diesen Reihenfolgen zunehmend bevorzugt mindestens 4,5, 4,8 oder 4,9 und höchstens 5,8, 5,5 oder 5,3 auf.The aqueous acid plating bath preferably has a pH of in these orders increasingly preferably at least 4.5, 4.8 or 4.9 and at most 5.8, 5.5 or 5.3.
Das wässrig alkalische galvanische Bad weist vorzugsweise einen pH-Wert von mindestens 12 und höchstens 14 auf, wobei hier ein pH-Wert von über 13 besonders bevorzugt ist.The aqueous alkaline galvanic bath preferably has a pH of at least 12 and at most 14, with a pH above 13 being particularly preferred here.
Die galvanische Behandlungsdauer zum Abscheiden der ersten Zinkschicht kann in diesen Reihenfolgen zunehmend bevorzugt mindesten 4 min, 6 min, 8 min oder 10 min und höchstens 30 min, 27 min, 24 min oder 20 min betragen. Dabei ist eine Badtemperatur von mindestens 12 °C oder 20 °C und höchstens 35 °C oder 30 °C bevorzugt.The galvanic treatment time for depositing the first zinc layer may be in these sequences increasingly preferably at least 4 min, 6 min, 8 min or 10 min and at most 30 min, 27 min, 24 min or 20 min. In this case, a bath temperature of at least 12 ° C or 20 ° C and at most 35 ° C or 30 ° C is preferred.
Die Behandlungsdauer zum Abscheiden der zweiten Zinkschicht aus dem alkalischen Bad kann in diesen Reihenfolgen zunehmend bevorzugt mindestens 15 min, 18 min oder 20 min und höchstens 45 min, 42 min oder 40 min betragen. Auch das alkalische Bad hat dabei vorzugsweise eine Temperatur von mindestens 15 °C oder 20 °C und höchstens 40 °C oder 30 °C.The treatment time for depositing the second zinc layer from the alkaline bath may be increasingly preferably at least 15 minutes, 18 minutes or 20 minutes and at most 45 minutes, 42 minutes or 40 minutes in these orders. Also, the alkaline bath preferably has a temperature of at least 15 ° C or 20 ° C and at most 40 ° C or 30 ° C.
Die Stromdichte bei der galvanischen Abscheidung der ersten Zinkschicht in dem sauren Bad beträgt vorzugsweise mindestens 0,3 A/dm2 und höchstens 2,5 A/dm2, und zwar vorzugsweise bei einer Spannung zwischen 1,5 V und 5 V. Die Stromdichte in dem alkalischen Bad beträgt vorzugsweise mindestens 0,5 A/dm2 und höchstens 5 A/dm2, und zwar bevorzugt bei einer Spannung von mindestens 3 V und höchstens 8 V.The current density in the electrodeposition of the first zinc layer in the acid bath is preferably at least 0.3 A / dm 2 and at most 2.5 A / dm 2 , preferably at a voltage between 1.5 V and 5 V. The current density in the alkaline bath is preferably at least 0.5 A / dm 2 and at most 5 A / dm 2 , preferably at a voltage of at least 3 V and at most 8 V.
Das saure galvanische Bad weist vorzugsweise in diesen Reihenfolgen zunehmend bevorzugt
mindestens 10 g/l, 20 g/l, 25 g/l oder 30 g/l und höchstens 60 g/l, 45 g/l oder 40 g/l Zink,
mindestens 80 g/l, 100 g/l oder 120 g/l und höchstens 200 g/l, 180 g/l oder 160 g/l Chlorid und
mindestens 10 g/l, 15 g/l, 20 g/l oder 25 g/l und höchstens 40 g/l oder 35 g/l Borsäure auf.The acid plating bath is preferably increasingly preferred in these orders
at least 10 g / l, 20 g / l, 25 g / l or 30 g / l and at most 60 g / l, 45 g / l or 40 g / l zinc,
at least 80 g / l, 100 g / l or 120 g / l and not more than 200 g / l, 180 g / l or 160 g / l chloride and
at least 10 g / l, 15 g / l, 20 g / l or 25 g / l and at most 40 g / l or 35 g / l boric acid.
Ferner kann das saure galvanische Bad zusätzlich in den jeweiligen Reihenfolgen zunehmend bevorzugt
mindestens 0,5 ml/l oder 0,8 ml/l und höchstens 2 ml/l oder 1,5 ml/l organischen Glanzzusatz und/oder
mindestens 30 ml/l und höchstens 80 ml/l oder 50 ml/l organische Tenside aufweisen.Furthermore, the acid plating bath may additionally be increasingly preferred in the respective orders
at least 0.5 ml / l or 0.8 ml / l and not more than 2 ml / l or 1.5 ml / l organic brightener additive and / or
at least 30 ml / l and not more than 80 ml / l or 50 ml / l of organic surfactants.
Dabei kann das saure Bad eine wässrige Lösung sein, die besonders bevorzugt bis auf eventuelle Verunreinigungen ausschließlich die zuvor genannten Komponenten aufweist.In this case, the acidic bath may be an aqueous solution which, with particular preference to all possible impurities, has exclusively the abovementioned components.
Das alkalische galvanische Bad kann in diesen Reihenfolgen zunehmend bevorzugt
mindestens 5 g/l oder 10 g/l und höchstens 20 g/l oder 14 g/l Zink,
mindestens 50 g/l oder 100 g/l und höchstens 200 g/l oder 140 g/l eines alkalischen Zusatzes aufweisen, wobei der alkalische Zusatz beispielsweise NaOH sein kann.The alkaline plating bath may be increasingly preferred in these orders
at least 5 g / l or 10 g / l and not more than 20 g / l or 14 g / l zinc,
at least 50 g / l or 100 g / l and at most 200 g / l or 140 g / l of an alkaline additive, wherein the alkaline additive may be, for example, NaOH.
Ferner kann das alkalische Bad in diesen Reihenfolgen zunehmend bevorzugt zusätzlich
mindestens 8 ml/l oder 10 ml/l und höchstens 20 ml/l oder 15 ml/l eines organischen Glanzträgers und/oder
mindestens 0,5 ml/l und höchstens 3 ml/l oder 2 ml/l eines organischen Glanzverstärkers aufweisen.Further, the alkaline bath in these orders may be increasingly preferred in addition
at least 8 ml / l or 10 ml / l and not more than 20 ml / l or 15 ml / l of an organic luster carrier and / or
at least 0.5 ml / l and at most 3 ml / l or 2 ml / l of an organic gloss enhancer.
Auch das alkalische galvanische Bad liegt vorzugsweise als wässrige Lösung vor und kann in einer besonders bevorzugten Ausführung neben eventuellen Verunreinigungen höchstens die zuvor genannten Komponenten in wässriger Lösung aufweisen.The alkaline galvanic bath is preferably in the form of an aqueous solution and, in a particularly preferred embodiment, may contain, in addition to possible impurities, at most the abovementioned components in aqueous solution.
Vorzugsweise wird nach dem Abscheiden der ersten Zinkschicht der zu beschichtende Gegenstand gespült, und zwar günstigerweise zumindest mit Wasser. Ebenso kann ein Spülen nach dem Abscheiden der zweiten galvanischen Zinkschicht erfolgen. Ferner ist eine Reinigung des zu beschichtenden Gegenstandes vor dem Abscheiden der ersten Zinkschicht vorteilhaft, wobei hier, insbesondere auch in Abhängigkeit des Materials des zu beschichtenden Gegenstandes, aus dem Stand der Technik zahlreiche Reinigungsverfahren bekannt sind. Auch kann zur Verbesserung des galvanischen Abscheidungsprozesses jeweils das galvanische Bad und/oder auch der zu beschichtende Gegenstand in dem Bad bewegt werden.Preferably, after the deposition of the first zinc layer, the object to be coated is rinsed, conveniently at least with water. Likewise, rinsing can take place after the deposition of the second galvanic zinc layer. Furthermore, a cleaning of the article to be coated prior to the deposition of the first zinc layer is advantageous, in which case, in particular, depending on the material of the article to be coated, from the prior art, numerous cleaning methods are known. Also, in order to improve the electrodeposition process, in each case the galvanic bath and / or also the object to be coated can be moved in the bath.
Bei einer vorteilhaften Ausführung der Beschichtung kann (insbesondere unmittelbar) auf die zweite Zinkschicht eine Dickschichtpassivierung folgen, wobei diese in einem chemischen Prozess in einem weiteren Bad aufgetragen werden kann. Durch eine solche zusätzliche Dickschichtpassivierung kann die mechanische Widerstandsfähigkeit der gesamten Beschichtung zusätzlich erhöht werden. Ebenso kann ein zusätzlicher Schutz gegen chemische Einflüsse erzielt werden.In an advantageous embodiment of the coating, a thick-layer passivation can follow (in particular directly) onto the second zinc layer, wherein it can be applied in a further process in a chemical bath in a further bath. Such an additional thick-film passivation can additionally increase the mechanical resistance of the entire coating. Likewise, an additional protection against chemical influences can be achieved.
Ebenso kann auch unmittelbar auf die zweite Zinkschicht oder auch unmittelbar auf die Dickschichtpassivierung folgend ein Lack aufgetragen werden. Dadurch lassen sich in bekannter Weise ebenfalls die mechanische Widerstandsfähigkeit und/oder der Schutz gegen chemische Einflüsse verbessern. Dabei kann der Lack durch elektrochemisches Tauchlackieren aufgetragen werden, vorzugsweise durch kathodisches Tauchlackieren, das auch als KTL-Beschichtung bezeichnet wird und aus dem Stand der Technik bekannt ist.Likewise, a lacquer can also be applied directly to the second zinc layer or also directly following the thick-layer passivation. As a result, the mechanical resistance and / or the protection against chemical influences can likewise be improved in a known manner. In this case, the paint can be applied by electrochemical dip coating, preferably by cathodic dip coating, which is also referred to as KTL coating and is known from the prior art.
Ein Gegenstand, der zumindest die beiden erfindungsgemäßen galvanischen Zinkschichten aufweist, kann als Bestandteil eines Kraftfahrzeuges eingesetzt werden, und zwar besonders bevorzugt als ein Bauteil, das von unterhalb des Fahrzeuges aus frei zugänglich ist. Dabei kann es ein Fahrzeugteil aus nicht rostfreiem Stahl sein und erfindungsgemäß vor Feuchtigkeit, korrosiven Substanzen wie beispielsweise Salz, aber auch mechanischen Einwirkungen auf seine Oberfläche geschützt sein. Besonders bevorzugt kann dabei ein Bestandteil einer Kfz-Bodengruppe, insbesondere ein Teil eines Antriebssystems oder einer Radaufhängung, beispielsweise ein Fahrschemel, eine erfindungsgemäße Beschichtung aufweisen.An article which has at least the two galvanic zinc layers according to the invention can be used as a component of a motor vehicle, particularly preferably as a component that is freely accessible from below the vehicle. It may be a vehicle part made of stainless steel and be protected according to the invention from moisture, corrosive substances such as salt, but also mechanical effects on its surface. Particularly preferred may be a component of a motor vehicle floor, in particular a part of a drive system or a suspension, for example a subframe, have a coating according to the invention.
Im folgenden wird die Erfindung anhand von Ausführungsbeispielen näher erläutert, wobei die einzelnen Merkmale auch in anderen Kombinationen, insbesondere auch mit der vorhergehenden Beschreibung, erfndungswesentlich sein können.In the following the invention will be explained in more detail by means of embodiments, wherein the individual features in other combinations, in particular with the preceding description, can be essential to the invention.
Ein aus einem nicht rostfreien Stahlblech gefertigter Fahrschemel wird in einer ersten Behandlung gereinigt, insbesondere entfettet und von Oberflächenoxiden befreit. Nach einem Spülvorgang in Wasser wird er in einem sauren galvanischen Bad bei 28 °C mit einem Strom von 0,6 A/dm2 unter einer Spannung von 2,7 V bei einer Behandlungsdauer von 15 min verzinkt. Das Bad mit einem pH-Wert von 5,0 besteht hier aus einer wässrigen Lösung von 35 g/l Zink, 140 g/l Chlorid, 30 g/l Borsäure, 1,2 ml/l organischem Glanzzusatz und 40 ml/l organischen Tensiden. In diesem Bad wird eine erste duktile gut haftende Zinkschicht von oberflächenrissiger Struktur von etwa 7 µm aufgetragen und der Achsschemel anschließend in Wasser gespült.A subframe made of a non-stainless steel sheet is cleaned in a first treatment, in particular degreased and freed from surface oxides. After rinsing in water, it is galvanized in an acid plating bath at 28 ° C with a current of 0.6 A / dm 2 under a voltage of 2.7 V at a treatment time of 15 min. The bath with a pH of 5.0 consists here of an aqueous solution of 35 g / l zinc, 140 g / l chloride, 30 g / l boric acid, 1.2 ml / l organic brightener and 40 ml / l organic surfactants. In this bath, a first ductile well-adhering zinc layer of surface-cracked structure of about 7 microns is applied and then rinsed the steering column in water.
Unmittelbar im Anschluss erfolgt eine weitere galvanische Behandlung in einem alkalischen Bad mit einem pH-Wert von etwa 14 und bei einer Temperatur von 26 °C. Hierbei wird eine zweite Zinkschicht während einer Behandlungsdauer von 30 min bei einer Stromdichte von 1 A/dm2 bei einer angelegten Spannung von 5,5 V abgeschieden. Dieses zweite galvanische Bad weist hierbei eine wässrige Lösung von 12 g/l Zink, 120 g/l NaOH, 12 ml/l organische Glanzträger und 1,2 ml/l organische Glanzverstärker auf. Insgesamt wird hier eine Schichtdicke von etwa 16 µm eines quasiamorphen Zinkgefüges abgeschieden, wobei nach der galvanischen Beschichtung der Fahrschemel nochmals mit Wasser gespült wird.Immediately afterwards, a further galvanic treatment takes place in an alkaline bath with a pH of about 14 and at a temperature of 26 ° C. Here, a second zinc layer is deposited during a treatment period of 30 minutes at a current density of 1 A / dm 2 at an applied voltage of 5.5 V. This second galvanic bath in this case has an aqueous solution of 12 g / l zinc, 120 g / l NaOH, 12 ml / l organic gloss and 1.2 ml / l organic gloss enhancer on. Overall, a layer thickness of about 16 microns of a quasi-amorphous zinc structure is deposited here, wherein after the galvanic coating of the subframe is rinsed again with water.
Bei einem weiteren Beispiel wird auf einem beschichteten Fahrschemel in einem weiteren Bad unmittelbar auf der zweiten Zinkschicht eine Dickschichtpassivierung chemisch abgeschieden und anschließend der Gegenstand wieder in einem Wasserbad gespült. Der so hergestellte Fahrschemel weist also eine Korrosionsschutzbeschichtung mit zwei unmittelbar aufeinander folgenden Zinkschichten und einer äußeren Dickschichtpassivierung auf.In another example, a thick film passivation is chemically deposited on a coated subframe in a further bath directly on the second zinc layer, and then the article is rinsed again in a water bath. Thus, the subframe produced in this way has a corrosion protection coating with two directly successive zinc layers and an outer thick-film passivation.
Ein weiteres Ausführungsbeispiel liegt in der Korrosionsschutzbeschichtung eines Fahrschemels, die sich von dem zuvor beschriebenen durch eine KTL-Beschichtung anstatt der Dickschichtpassivierung unterscheidet.Another embodiment resides in the anti-corrosion coating of a subframe which differs from that previously described by a cathodic dip-coating rather than the thick-film passivation.
Ein viertes Ausführungsbeispiel entspricht dem ersten, weist also zwei aufeinanderfolgende erfindungsgemäße Zinkschichten auf. Zusätzlich ist unmittelbar auf der zweiten Zinkschicht eine Dickschichtpassivierung und unmittelbar auf dieser eine KTL-Beschichtung aufgetragen. Dieses Ausführungsbeispiel hat also eine Korrosionsschutzbeschichtung mit diesen vier aufeinander folgenden Schichten.A fourth embodiment corresponds to the first, thus has two successive zinc layers according to the invention. In addition, a thick-film passivation is applied directly to the second zinc layer and directly to this one KTL coating. This embodiment thus has a corrosion protection coating with these four successive layers.
Claims (15)
eine erste Zinkschicht mit einer Dicke von mindestens 4 µm in einem sauren galvanischen Bad und
unmittelbar auf der ersten eine zweite Zinkschicht mit einer Dicke von mindestens 5 µm in einem alkalischen galvanischen Bad abgeschieden wird.Process for anticorrosive coating, in which
a first zinc layer with a thickness of at least 4 microns in an acidic plating bath and
immediately on the first a second zinc layer is deposited with a thickness of at least 5 microns in an alkaline galvanic bath.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP08014206A EP2157213B1 (en) | 2008-08-08 | 2008-08-08 | Anti-corrosion coating with two zinc layers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP08014206A EP2157213B1 (en) | 2008-08-08 | 2008-08-08 | Anti-corrosion coating with two zinc layers |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP2157213A1 true EP2157213A1 (en) | 2010-02-24 |
| EP2157213B1 EP2157213B1 (en) | 2012-10-24 |
Family
ID=40089918
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP08014206A Expired - Fee Related EP2157213B1 (en) | 2008-08-08 | 2008-08-08 | Anti-corrosion coating with two zinc layers |
Country Status (1)
| Country | Link |
|---|---|
| EP (1) | EP2157213B1 (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3129129A1 (en) * | 1981-07-20 | 1983-02-03 | Schering Ag, 1000 Berlin Und 4619 Bergkamen | Method for the electrodeposition of very bright, strongly adhering zinc coatings employing alkaline cyanide-free baths |
| JPS61183491A (en) * | 1985-02-08 | 1986-08-16 | Usui Internatl Ind Co Ltd | Corrosion resistant double coated steel material |
| DE19716375A1 (en) * | 1997-04-18 | 1998-10-22 | Alfred R Franz Fa | Two-stage zinc electroplating of metal article |
| DE19837431A1 (en) * | 1998-08-18 | 2000-02-24 | Schloetter Fa Dr Ing Max | Hardened steel or cast iron is electroplated with a zinc-cobalt or zinc-nickel alloy layer from an acidic bath and then a zinc-nickel alloy layer from an alkaline bath, especially for corrosion protection of automobile components |
-
2008
- 2008-08-08 EP EP08014206A patent/EP2157213B1/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3129129A1 (en) * | 1981-07-20 | 1983-02-03 | Schering Ag, 1000 Berlin Und 4619 Bergkamen | Method for the electrodeposition of very bright, strongly adhering zinc coatings employing alkaline cyanide-free baths |
| JPS61183491A (en) * | 1985-02-08 | 1986-08-16 | Usui Internatl Ind Co Ltd | Corrosion resistant double coated steel material |
| DE19716375A1 (en) * | 1997-04-18 | 1998-10-22 | Alfred R Franz Fa | Two-stage zinc electroplating of metal article |
| DE19837431A1 (en) * | 1998-08-18 | 2000-02-24 | Schloetter Fa Dr Ing Max | Hardened steel or cast iron is electroplated with a zinc-cobalt or zinc-nickel alloy layer from an acidic bath and then a zinc-nickel alloy layer from an alkaline bath, especially for corrosion protection of automobile components |
Also Published As
| Publication number | Publication date |
|---|---|
| EP2157213B1 (en) | 2012-10-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| DE2938940C2 (en) | Multi-layer plating and its use | |
| DE102010055968A1 (en) | Substrate with corrosion-resistant coating and process for its preparation | |
| DE3028587A1 (en) | METHOD FOR PRODUCING A SPECIAL FINE SHEET FOR PERMANENT CAR BODIES AND A FINE SHEET PRODUCED THEREFORE | |
| DE3118375A1 (en) | METHOD FOR PHOSPHATING METALS AND ITS APPLICATION FOR PRE-TREATMENT FOR ELECTRO DIP PAINTING | |
| DE1068970B (en) | Electroplating of black nickel coatings and pretreatment of the workpieces to be coated | |
| EP2588645B1 (en) | Method for depositing a nickel-metal layer | |
| DE69211167T2 (en) | Process for direct zinc electroplating of aluminum strip | |
| DE2837055C2 (en) | Process for pretreating a steel surface to be painted or varnished and a bath for carrying out this process | |
| DE3414048A1 (en) | METHOD FOR PRODUCING STEEL PARTS GALVANIZED WITH A ZINC-NICKEL ALLOY | |
| DE3024932C2 (en) | ||
| EP0154367A2 (en) | Process for phosphatizing metals | |
| DE2141614B2 (en) | WORKPIECES MADE OF STEEL OR IRON WITH GALVANIC APPLIED ZINC COATING WITH IMPROVED PROPERTIES WITH REGARD TO CORROSION RESISTANCE AND ADHESION TO PAINTING AS WELL AS GOOD FORMATABILITY AND PRODUCTION PROCESS | |
| EP0366941B1 (en) | Process for the electrophoretic coating of chromizable metal surfaces | |
| DE102017206990A1 (en) | Process for wastewater treatment in a painting process and plant for painting components | |
| DE202008010569U1 (en) | Anti-corrosion coating with two zinc layers | |
| EP2157213B1 (en) | Anti-corrosion coating with two zinc layers | |
| EP2770088A1 (en) | Extremely corrosion-resistant steel parts and method for their production | |
| DE2046449A1 (en) | Process for applying protective coatings to metal objects | |
| DE3339856A1 (en) | METHOD FOR THE ADHESIVE ACTIVATION OF POLYAMIDE SUBSTRATES FOR CURRENT METALLIZATION | |
| DE102016008333A1 (en) | Process for the low-hydrogen zinc-nickel coating of a high-strength tempered steel | |
| DE2256032B2 (en) | Fastening means made of carbon steel with a protective fiber covering made of electrodeposited metal layers | |
| DE2618638B2 (en) | Electroplating bath and process for the deposition of coatings from tin-containing alloys | |
| DE102018127345A1 (en) | PROCESS FOR COATING A RAW BODY STRUCTURE WITH AT LEAST ONE SURFACE CONTAINING AN ALUMINUM ALLOY | |
| DE3429279C2 (en) | ||
| DE102007048043A1 (en) | Galvanic deposition of metal layers on magnesium or magnesium alloy surfaces |
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 |
|
| 17P | Request for examination filed |
Effective date: 20090515 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR |
|
| AX | Request for extension of the european patent |
Extension state: AL BA MK RS |
|
| AKX | Designation fees paid |
Designated state(s): AT DE FR GB IT |
|
| GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
| GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
| GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
| AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT DE FR GB IT |
|
| REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D Free format text: NOT ENGLISH |
|
| REG | Reference to a national code |
Ref country code: AT Ref legal event code: REF Ref document number: 581023 Country of ref document: AT Kind code of ref document: T Effective date: 20121115 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R096 Ref document number: 502008008460 Country of ref document: DE Effective date: 20121213 |
|
| 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 |
Effective date: 20130725 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R097 Ref document number: 502008008460 Country of ref document: DE Effective date: 20130725 |
|
| GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20130808 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20130808 |
|
| REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 8 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20150820 Year of fee payment: 8 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20150824 Year of fee payment: 8 Ref country code: AT Payment date: 20150820 Year of fee payment: 8 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: IT Payment date: 20150827 Year of fee payment: 8 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R119 Ref document number: 502008008460 Country of ref document: DE |
|
| REG | Reference to a national code |
Ref country code: AT Ref legal event code: MM01 Ref document number: 581023 Country of ref document: AT Kind code of ref document: T Effective date: 20160808 |
|
| REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20170428 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160808 |
|
| 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: 20170301 Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160831 |
|
| 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 Effective date: 20160808 |