EP0698675B1 - Preparing metal surfaces for enamelling - Google Patents
Preparing metal surfaces for enamelling Download PDFInfo
- Publication number
- EP0698675B1 EP0698675B1 EP95112122A EP95112122A EP0698675B1 EP 0698675 B1 EP0698675 B1 EP 0698675B1 EP 95112122 A EP95112122 A EP 95112122A EP 95112122 A EP95112122 A EP 95112122A EP 0698675 B1 EP0698675 B1 EP 0698675B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- metal surfaces
- phosphating solution
- contact
- brought
- phosphate
- 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
- 229910052751 metal Inorganic materials 0.000 title claims description 35
- 239000002184 metal Substances 0.000 title claims description 35
- 238000000034 method Methods 0.000 claims description 32
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 17
- 229910019142 PO4 Inorganic materials 0.000 claims description 16
- 239000010452 phosphate Substances 0.000 claims description 16
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 12
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims description 10
- 229910002651 NO3 Inorganic materials 0.000 claims description 8
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 8
- 239000002320 enamel (paints) Substances 0.000 claims description 7
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- 150000001768 cations Chemical class 0.000 claims description 5
- 229910017052 cobalt Inorganic materials 0.000 claims description 5
- 239000010941 cobalt Substances 0.000 claims description 5
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 5
- MEFBJEMVZONFCJ-UHFFFAOYSA-N molybdate Chemical compound [O-][Mo]([O-])(=O)=O MEFBJEMVZONFCJ-UHFFFAOYSA-N 0.000 claims description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 3
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 3
- 239000004202 carbamide Substances 0.000 claims description 3
- 229910052725 zinc Inorganic materials 0.000 claims description 3
- 239000011701 zinc Substances 0.000 claims description 3
- 229940104869 fluorosilicate Drugs 0.000 claims description 2
- JKQOBWVOAYFWKG-UHFFFAOYSA-N molybdenum trioxide Chemical compound O=[Mo](=O)=O JKQOBWVOAYFWKG-UHFFFAOYSA-N 0.000 claims 2
- 235000011149 sulphuric acid Nutrition 0.000 claims 1
- 239000001117 sulphuric acid Substances 0.000 claims 1
- 239000010410 layer Substances 0.000 description 15
- 210000003298 dental enamel Anatomy 0.000 description 9
- 229910000831 Steel Inorganic materials 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 3
- 239000011241 protective layer Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- YUZILKLGVPUFOT-YHPRVSEPSA-L disodium;5-[(6-anilino-4-oxo-1h-1,3,5-triazin-2-yl)amino]-2-[(e)-2-[4-[(6-anilino-4-oxo-1h-1,3,5-triazin-2-yl)amino]-2-sulfonatophenyl]ethenyl]benzenesulfonate Chemical compound [Na+].[Na+].C=1C=C(\C=C\C=2C(=CC(NC=3NC(NC=4C=CC=CC=4)=NC(=O)N=3)=CC=2)S([O-])(=O)=O)C(S(=O)(=O)[O-])=CC=1NC(N1)=NC(=O)N=C1NC1=CC=CC=C1 YUZILKLGVPUFOT-YHPRVSEPSA-L 0.000 description 2
- -1 fluoride ions Chemical class 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 229910000159 nickel phosphate Inorganic materials 0.000 description 2
- JOCJYBPHESYFOK-UHFFFAOYSA-K nickel(3+);phosphate Chemical compound [Ni+3].[O-]P([O-])([O-])=O JOCJYBPHESYFOK-UHFFFAOYSA-K 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 239000005569 Iron sulphate Substances 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- VEQPNABPJHWNSG-UHFFFAOYSA-N Nickel(2+) Chemical compound [Ni+2] VEQPNABPJHWNSG-UHFFFAOYSA-N 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
- 238000005844 autocatalytic reaction Methods 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910001463 metal phosphate Inorganic materials 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910001453 nickel ion Inorganic materials 0.000 description 1
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 1
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- PBYZMCDFOULPGH-UHFFFAOYSA-N tungstate Chemical compound [O-][W]([O-])(=O)=O PBYZMCDFOULPGH-UHFFFAOYSA-N 0.000 description 1
- LSGOVYNHVSXFFJ-UHFFFAOYSA-N vanadate(3-) Chemical compound [O-][V]([O-])([O-])=O LSGOVYNHVSXFFJ-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
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
- 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
- C23C22/40—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 molybdates, tungstates or vanadates
- C23C22/44—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 molybdates, tungstates or vanadates containing also fluorides or complex fluorides
-
- 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
- C23D—ENAMELLING OF, OR APPLYING A VITREOUS LAYER TO, METALS
- C23D3/00—Chemical treatment of the metal surfaces prior to coating
Definitions
- the invention relates to a method for preparing metal surfaces for the application of an enamel coating by producing a phosphate layer by means of a phosphating solution which contains layer-forming cation as well as phosphate, nitrate and fluoride.
- the workpiece to be treated usually consists of high-quality steel with a special, low-carbon surface and requires a comparatively complex production.
- the sequence of processes often comprises 16 steps or more, of which approximately 5 are used for cleaning, approximately 4 for rust removal (if there are signs of rust) and the rest are used to produce a protective layer including rinsing and neutralization. Only then will the email be sent.
- the aforementioned protective layer is often produced by immersing the workpieces in a nickel sulfate solution.
- GB-PS 755 559 From GB-PS 755 559 it is known to produce a phosphate layer, usually a heavy metal phosphate, as a protective layer, to convert at least a part thereof into oxide by heating and then to enamel it. This method can neither achieve good results nor is it easy to carry out, so that it has not become established.
- GB-PS 1 498 490 it is known to be a Apply nickel phosphate layer to prepare the metal surface before painting or enamelling. With this method, however, it is necessary to activate the metal surface before contact with the phosphating solution. Nickel phosphate layers with a considerable layer weight are formed. However, the liability of the subsequently applied email cover is also unsatisfactory. The situation is similar in other known methods. Either their economy is at the limit due to the complexity of the pretreatment process or it is necessary to apply at least two enamel coatings in succession to obtain satisfactory liability.
- a phosphate layer by means of a phosphating solution, for example 0.1 to 2 g / l nickel ions, 1 to 12 g / l phosphate ions, for preparing metal surfaces for applying an enamel coating as well as nitrate and fluoride ions.
- the aim of the last-mentioned method is in particular to produce a phosphate layer with a layer weight of 0.15 to 0.6 g / m 2 .
- EP-A-0 015 020 discloses a method for preparing metal surfaces for subsequent coating with organic coatings by applying a phosphate coating by wetting with a phosphating liquid containing at least divalent cations and then drying the liquid film, in which the metal surface coexists a phosphating liquid is wetted, which has a pH of 1.5 to 3.0, is chromate-free and, in addition to metal phosphate, contains soluble molybdate, tungstate, vanadate, niobate and / or tantalate ions, the phosphating liquid additionally being simple or can contain complex-bound fluoride ions and the cationic component of the phosphating liquid is formed by calcium, magnesium, barium, aluminum, zinc, cadmium, iron, nickel, cobalt and / or manganese.
- This known method is to be used in particular for the pretreatment of aluminum.
- the main advantages of the known method are that the layers obtained are non-toxic, provide high protection against corrosion and have good adhesion-promoting properties for organic coatings, in particular for paints, adhesives and plastics.
- the object of the invention is to provide a method for preparing metal surfaces for the application of an enamel coating, which ensures high adhesion even with a single application of the enamel and largely independent of the quality of the treated steel, the treatment should be simple and economical.
- 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 nickel and / or cobalt as a layer-forming cation in amounts of 0.5 to 3 g / l such as 5 to 20 g / l Phosphate (calc. As P 2 O 5 ), 0.1 to 0.5 g / l Molybdate (calculated as MoO 3 ), 0.2 to 2 g / l Fluoride (calc. As F), 1 to 10 g / l Nitrate (calc. As NO 3 ) contains.
- a phosphating solution which contains nickel and / or cobalt as a layer-forming cation in amounts of 0.5 to 3 g / l such as 5 to 20 g / l Phosphate (calc. As P 2 O 5 ), 0.1 to 0.5 g / l Molybdate (calculated as MoO
- a preferred embodiment of the invention provides for the metal surfaces to be brought into contact with a phosphating solution which 1 to 2 g / l Nickel and / or cobalt 8 to 18 g / l Phosphate, 0.2 to 0.3 g / l Molybdate, 0.4 to 1 g / l Fluoride as well 2 to 5 g / l nitrate contains.
- a phosphating solution which 1 to 2 g / l Nickel and / or cobalt 8 to 18 g / l Phosphate, 0.2 to 0.3 g / l Molybdate, 0.4 to 1 g / l Fluoride as well 2 to 5 g / l nitrate contains.
- a phosphating solution which additionally contains 0.1 to 5 g / l, preferably 0.2 to 2 g / l, of urea. This ensures that any nitrite formed in the phosphating solution is destroyed by the autocatalytic reaction.
- fluoride component into the phosphating solution as single fluoride or as fluorosilicate.
- the phosphating treatment can be carried out by dipping or spraying. Temperatures in the range from 40 to 80 ° C., preferably from 60 to 70 ° C., are advantageously set as the treatment temperature. The duration of the phosphating treatment is advantageously in the range from 2 to 15 minutes, preferably in the range from 4 to 10 minutes.
- An advantageous embodiment of the invention consists in bringing the metal surfaces into contact with the phosphating solution in such a way that a phosphate layer weight of 1.0 to 2.0 g / m 2 results.
- the phosphate layer with such a layer weight enables optimal anchoring and thus adhesion of the enamel layer.
- metal surfaces to be phosphated are contaminated, it is necessary to precede the phosphating treatment with a cleaning, for example a conventional alkaline cleaning, and then to rinse it.
- a cleaning for example a conventional alkaline cleaning
- a pickling of the metal surface is necessary. Sulfuric acid is particularly advantageous for this.
- a favorable embodiment consists in pickling in such a way that the metal removal from the metal surface is 2 to 10 g / m 2 .
- rinsing is usually carried out in one or more stages.
- enamel frits can be used for the final enamelling.
- the enamelling can be done as a so-called single-layer enamelling in one step or with several enamel orders burned in one after the other.
- the inventive method of preparing metal surfaces for enamelling is characterized in that the number of treatment stages is significantly reduced, the capacity is increased, the throughput time is reduced and the investment costs for the pretreatment system are reduced.
- cover hoods for instantaneous water heater made of sheet steel for the subsequent direct white enamelling are treated as follows:
- the quality of the enamel layers corresponds to that which was produced according to the usual process. This procedure is characterized in that the aforementioned zones 9 and 10 are omitted, but instead the following zones 14 to 19 are connected:
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Treatment Of Metals (AREA)
Description
Die Erfindung betrifft ein Verfahren zur Vorbereitung von Metalloberflächen für das Aufbringen eines Emailüberzuges durch Erzeugen einer Phosphatschicht mittels einer Phosphatierungslösung, die schichtbildendes Kation sowie Phosphat, Nitrat und Fluorid enthält.The invention relates to a method for preparing metal surfaces for the application of an enamel coating by producing a phosphate layer by means of a phosphating solution which contains layer-forming cation as well as phosphate, nitrate and fluoride.
Es ist bekannt, Metalloberflächen, die mit einem Emailüberzug versehen werden sollen, einer aufwendigen Folge von Verfahrensschritten zu unterwerfen, bevor schließlich das Email aufgebracht wird. Das zu behandelnde Werkstück besteht üblicherweise aus hochwertigem Stahl mit einer speziellen, niedrig gekohlten Oberfläche und fordert eine vergleichsweise aufwendige Fertigung. Die Verfahrensfolge umfaßt häufig 16 Schritte und mehr, von denen ca. 5 der Reinigung, ca. 4 der Entrostung (sofern Anzeichen von Rost vorhanden sind) und die restlichen der Erzeugung einer Schutzschicht einschließlich Spülung und Neutralisation dienen. Erst dann erfolgt der Auftrag des Emails. Die Erzeugung der vorgenannten Schutzschicht erfolgt häufig durch Eintauchen der Werkstücke in eine Nickelsulfat-Lösung.It is known to subject metal surfaces that are to be provided with an enamel coating to a complex sequence of process steps before the enamel is finally applied. The workpiece to be treated usually consists of high-quality steel with a special, low-carbon surface and requires a comparatively complex production. The sequence of processes often comprises 16 steps or more, of which approximately 5 are used for cleaning, approximately 4 for rust removal (if there are signs of rust) and the rest are used to produce a protective layer including rinsing and neutralization. Only then will the email be sent. The aforementioned protective layer is often produced by immersing the workpieces in a nickel sulfate solution.
Aus der GB-PS 755 559 ist es bekannt, als Schutzschicht eine Phosphatschicht, gewöhnlich ein Schwermetallphosphat, zu erzeugen, mindestens einen Teil hiervon durch Erhitzen in Oxid zu überführen und dann zu emaillieren. Mit diesem Verfahren lassen sich weder gute Ergebnisse erzielen noch ist es einfach durchzuführen, so daß es sich nicht durchgesetzt hat. Gemäß der GB-PS 1 498 490 ist es bekannt, eine Nickelphosphatschicht zur Vorbereitung der Metalloberfläche vor dem Lackieren oder Emaillieren aufzubringen. Bei diesem Verfahren ist es jedoch erforderlich, die Metalloberfläche vor dem Kontakt mit der Phosphatierungslösung zu aktivieren. Es entstehen Nickelphosphatschichten mit einem erheblichen Schichtgewicht. Die Haftung des anschließend aufgebrachten Emailüberzuges ist jedoch auch hierbei nicht zufriedenstellend. In ähnlicher Weise verhält es sich auch bei anderen bekannten Verfahren. Entweder liegt ihre Wirtschaftlichkeit wegen der Vielstufigkeit des Vorbehandlungsverfahrens an der Grenze oder es ist zum Erhalt einer zufriedenstellenden Haftung erforderlich, nacheinander wenigstens zwei Emailüberzüge aufzubringen.From GB-PS 755 559 it is known to produce a phosphate layer, usually a heavy metal phosphate, as a protective layer, to convert at least a part thereof into oxide by heating and then to enamel it. This method can neither achieve good results nor is it easy to carry out, so that it has not become established. According to GB-PS 1 498 490 it is known to be a Apply nickel phosphate layer to prepare the metal surface before painting or enamelling. With this method, however, it is necessary to activate the metal surface before contact with the phosphating solution. Nickel phosphate layers with a considerable layer weight are formed. However, the liability of the subsequently applied email cover is also unsatisfactory. The situation is similar in other known methods. Either their economy is at the limit due to the complexity of the pretreatment process or it is necessary to apply at least two enamel coatings in succession to obtain satisfactory liability.
Weiterhin ist es aus der DE-A-36 35 896 bekannt, zur Vorbereitung von Metalloberflächen für das Aufbringen eines Emailüberzuges eine Phosphatschicht mittels einer Phosphatierungslösung zu erzeugen, die beispielsweise 0,1 bis 2 g/l Nickelionen, 1 bis 12 g/l Phosphationen sowie Nitrat- und Fluoridionen enthält. Das Ziel des zuletzt genannten Verfahrens liegt insbesondere darin, eine Phosphatschicht mit einem Schichtgewicht von 0,15 bis 0,6 g/m2 zu erzeugen.Furthermore, it is known from DE-A-36 35 896 to prepare a phosphate layer by means of a phosphating solution, for example 0.1 to 2 g / l nickel ions, 1 to 12 g / l phosphate ions, for preparing metal surfaces for applying an enamel coating as well as nitrate and fluoride ions. The aim of the last-mentioned method is in particular to produce a phosphate layer with a layer weight of 0.15 to 0.6 g / m 2 .
Obgleich das zuletzt skizzierte Verfahren gegenüber den zuvor genannten bereits gewisse Fortschritte aufweist, haftet ihm dennoch der Nachteil an, daß je nach Stahlqualität die Haftung insbesondere bei der Einschicht-Emaillierung nicht zufriedenstellend ist. Generell läßt sich sagen, daß sich Phosphatierverfahren zur Vorbereitung von Metalloberflächen für die Emaillierung in der Praxis nicht durchsetzen konnten. Schließlich ist aus der EP-A-0 015 020 ein Verfahren zur Vorbereitung von Metalloberflächen zur anschließenden Beschichtung mit organischen Überzügen durch Aufbringen eines Phosphatüberzuges mittels Benetzen mit einer mindestens zwei-wertige Kationen enthaltenden Phosphatierungsflüssigkeit und anschließendes Auftrocknen des Flüssigkeitsfilms bekannt, bei dem die Metalloberfläche mit einer Phosphatierungsflüssigkeit benetzt wird, die einen pH-Wert von 1,5 bis 3,0 aufweist, chromatfrei ist und neben Metallphosphat lösliche Molybdat-, Wolframat-, Vanadat-, Niobat- und/oder Tantalat-Ionen enthält, wobei die Phosphatierungsflüssigkeit zusätzlich einfache oder komplexgebundene Fluoridionen enthalten kann und wobei die kationische Komponente der Phosphatierungsflüssigkeit durch Kalzium, Magnesium, Barium, Aluminium, Zink, Cadmium, Eisen, Nickel, Kobalt und/oder Mangan gebildet wird. Dieses bekannte Verfahren soll insbesondere zur Vorbehandlung von Aluminium verwendet werden. Die wesentlichen Vorteile des bekannten Verfahrens bestehen darin, daß die erhaltenen Schichten nicht toxisch sind, hohen Korrosionsschutz bewirken und gute Haftvermittlungseigenschaften für organische Überzüge, insbesondere für Lacke, Kleber und Kunststoffe, besitzen. Aufgabe der Erfindung ist es, ein Verfahren zur Vorbereitung von Metalloberflächen für das Aufbringen eines Emailüberzuges bereitzustellen, das eine hohe Haftung auch bei einmaligem Auftrag des Emails und weitestgehend unabhängig von der Qualität des behandelten Stahles gewährleistet, wobei die Behandlungsweise einfach und wirtschaftlich erfolgen soll.Although the process outlined above has already made some progress compared to the aforementioned, it has the disadvantage that, depending on the steel quality, the adhesion is unsatisfactory, particularly in the case of single-layer enamelling. In general, it can be said that phosphating processes for preparing metal surfaces for enamelling have not been successful in practice. Finally, EP-A-0 015 020 discloses a method for preparing metal surfaces for subsequent coating with organic coatings by applying a phosphate coating by wetting with a phosphating liquid containing at least divalent cations and then drying the liquid film, in which the metal surface coexists a phosphating liquid is wetted, which has a pH of 1.5 to 3.0, is chromate-free and, in addition to metal phosphate, contains soluble molybdate, tungstate, vanadate, niobate and / or tantalate ions, the phosphating liquid additionally being simple or can contain complex-bound fluoride ions and the cationic component of the phosphating liquid is formed by calcium, magnesium, barium, aluminum, zinc, cadmium, iron, nickel, cobalt and / or manganese. This known method is to be used in particular for the pretreatment of aluminum. The main advantages of the known method are that the layers obtained are non-toxic, provide high protection against corrosion and have good adhesion-promoting properties for organic coatings, in particular for paints, adhesives and plastics. The object of the invention is to provide a method for preparing metal surfaces for the application of an enamel coating, which ensures high adhesion even with a single application of the enamel and largely independent of the quality of the treated steel, the treatment should be simple and economical.
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 Kontakt bringt, die als schichtbildendes Kation Nickel und/oder Kobalt in Mengen von 0,5 bis 3 g/l sowie
Eine bevorzugte Ausgestaltung der Erfindung sieht vor, die Metalloberflächen mit einer Phosphatierungslösung in Kontakt zu bringen, die
Weiterhin ist vorteilhaft, die Metalloberflächen mit einer Phosphatierungslösung in Kontakt zu bringen, die zusätzlich 0,1 bis 5 g/l, vorzugsweise 0,2 bis 2 g/l, Harnstoff enthält. Hierdurch ist Gewähr dafür gegeben, daß in der Phosphatierungslösung ggf. durch autokatalytische Reaktion entstandenes Nitrit zerstört wird.It is also advantageous to bring the metal surfaces into contact with a phosphating solution which additionally contains 0.1 to 5 g / l, preferably 0.2 to 2 g / l, of urea. This ensures that any nitrite formed in the phosphating solution is destroyed by the autocatalytic reaction.
Besonders zweckmäßig ist es, die Fluoridkomponente in die Phosphatierungslösung als Einfachfluorid oder als Fluorosilikat einzubringen.It is particularly expedient to introduce the fluoride component into the phosphating solution as single fluoride or as fluorosilicate.
Im Hinblick auf die Haftung des nachfolgend aufgebrachten Emailüberzuges ist es von Vorteil, die Metalloberflächen mit einer Phosphatierungslösung in Kontakt zu bringen, die praktisch zinkfrei ist. Hierdurch wird sichergestellt, daß eine bei den hohen Emailliertemperaturen nicht auszuschließende Verdampfung von Zink unterbleibt.With regard to the adhesion of the enamel coating applied below, it is advantageous to bring the metal surfaces into contact with a phosphating solution that is practically zinc-free. This ensures that there is no evaporation of zinc at the high enamelling temperatures.
Die Phosphatierbehandlung kann im Tauchen oder Spritzen erfolgen. Als Behandlungstemperatur werden vorteilhafterweise Temperaturen im Bereich von 40 bis 80°C, vorzugsweise von 60 bis 70°C eingestellt. Die Dauer der Phosphatierbehandlung liegt vorteilhafterweise im Bereich von 2 bis 15 min., vorzugsweise im Bereich von 4 bis 10 min.The phosphating treatment can be carried out by dipping or spraying. Temperatures in the range from 40 to 80 ° C., preferably from 60 to 70 ° C., are advantageously set as the treatment temperature. The duration of the phosphating treatment is advantageously in the range from 2 to 15 minutes, preferably in the range from 4 to 10 minutes.
Eine vorteilhafte Ausführungsform der Erfindung besteht darin, die Metalloberflächen in der Weise mit der Phosphatierungslösung in Kontakt zu bringen, daß ein Phosphatschichtgewicht von 1,0 bis 2,0 g/m2 resultiert. Die Phosphatschicht mit einem derartigen Schichtgewicht ermöglicht die optimale Verankerung und damit Haftung der Emailschicht.An advantageous embodiment of the invention consists in bringing the metal surfaces into contact with the phosphating solution in such a way that a phosphate layer weight of 1.0 to 2.0 g / m 2 results. The phosphate layer with such a layer weight enables optimal anchoring and thus adhesion of the enamel layer.
Sofern die zu phosphatierenden Metalloberflächen verunreinigt sind, ist es erforderlich, der Phosphatierbehandlung eine Reinigung, beispielsweise eine konventionelle alkalische Reinigung, vorzuschalten und anschließend zu spülen.If the metal surfaces to be phosphated are contaminated, it is necessary to precede the phosphating treatment with a cleaning, for example a conventional alkaline cleaning, and then to rinse it.
Je nach der zu behandelnden Stahlqualität ist eine Beizung der Metalloberfläche notwendig. Hierfür ist insbesondere Schwefelsäure von Vorteil. Eine günstige Ausführungsform besteht darin, in der Weise zu beizen, daß der Metallabtrag von der Metalloberfläche 2 bis 10 g/m2 beträgt.Depending on the steel quality to be treated, a pickling of the metal surface is necessary. Sulfuric acid is particularly advantageous for this. A favorable embodiment consists in pickling in such a way that the metal removal from the metal surface is 2 to 10 g / m 2 .
Im Anschluß an die Phosphatierbehandlung wird üblicherweise in ein oder mehreren Stufen gespült.After the phosphating treatment, rinsing is usually carried out in one or more stages.
Zur abschließenden Emaillierung können herkömmliche Emailfritten eingesetzt werden. Die Emaillierung kann als sogenannte Einschicht-Emaillierung einstufig oder mit mehreren nacheinander eingebrannten Email-Aufträgen erfolgen.Conventional enamel frits can be used for the final enamelling. The enamelling can be done as a so-called single-layer enamelling in one step or with several enamel orders burned in one after the other.
Das erfindungsgemäße Verfahren der Vorbereitung von Metalloberflächen für die Emaillierung zeichnet sich dadurch aus, daß die Anzahl der Behandlungsstufen deutlich reduziert, die Kapazität gesteigert, die Durchlaufzeit reduziert und die Investitionskosten für die Vorbehandlungsanlage gesenkt werden.The inventive method of preparing metal surfaces for enamelling is characterized in that the number of treatment stages is significantly reduced, the capacity is increased, the throughput time is reduced and the investment costs for the pretreatment system are reduced.
Ferner ist bedeutsam, daß der Anfall an Eisensulfat-Schlamm durch Wegfall der Hauptbeize sowie des Vernickelungsbades auf etwa ein Viertel der ursprünglichen Menge zurückgeht. Dies bedeutet einen entsprechenden Rückgang der beträchtlichen Kosten für Entsorgung, d. h. vor allem der fürs Deponieren. Diese Vorteile werden ohne Einbuße beispielsweise hinsichtlich der Emailhaftung erzielt.It is also important that the amount of iron sulphate sludge is reduced to around a quarter of the original amount due to the absence of the main stain and the nickel plating bath. This means a corresponding decrease in the considerable disposal costs, i. H. especially that for depositing. These advantages are achieved, for example, in terms of email liability.
Die Erfindung wird anhand des nachfolgenden Beispiels näher und beispielsweise erläutert.The invention is explained in more detail and, for example, using the example below.
Gemäß dem erfindungsgemäßen Verfahren werden Abdeckhauben für Durchlauferhitzer aus Stahlblech für die anschließende Direktweiß-Emaillierung wie folgt behandelt:
Anschließend wurden die Abdeckhauben im Ofen getrocknet und in üblicher Weise mit Email (Direktweiß) beschichtet.The covers were then dried in the oven and coated with enamel (direct white) in the usual way.
Nach dem Einbrennen resultierten einwandfreie weiße, optisch gleichmäßige und gut haftende Emailschichten.After baking, the result was flawless white, optically uniform and well-adhering enamel layers.
Die Emailschichten entsprechen in ihrer Qualität denen, die nach dem in der Praxis üblichen Verfahrensgang erzeugt wurden. Dieser Verfahrensgang zeichnet sich dadurch aus, daß die vorgenanntn Zonen 9 und 10 entfallen, statt dessen jedoch die folgenden Zonen 14 bis 19 angeschlossen werden:
Claims (13)
- A method for preparing metal surfaces for the application of an enamel coating by producing a phosphate layer by means of a phosphating solution which contains layer-forming cation and also phosphate, nitrate and fluoride, characterised in that the metal surfaces are brought into contact with a phosphating solution which contains as layer-forming cation nickel and/or cobalt in quantities of 0.5 to 3 g/l and 5 to 20 g/l phosphate (calculated as P2O5), 0.1 to 0.5 g/l molybdate (calculated as MoO3), 0.2 to 2 g/l fluoride (calculated as F) and 1 to 10 g/l nitrate (calculated as NO3).
- A method according to Claim 1, characterised in that the metal surfaces are brought into contact with a phosphating solution which contains 1 to 2 g/l nickel and/or cobalt, 8 to 18 g/l phosphate, 0.2 to 0.3 g/l molybdate, 0.4 to 1 g/l fluoride and 2 to 5 g/l nitrate.
- A method according to Claim 1 or 2, characterised in that the metal surfaces are brought into contact with a phosphating solution which additionally contains 0.1 to 5 g/l urea.
- A method according to Claim 3, characterised in that the metal surfaces are brought into contact with a phosphating solution which contains 0.2 to 2 g/l urea.
- A method according to one or more of Claims 1 to 4, characterised in that the metal surfaces are brought into contact with a phosphating solution which contains fluoride in the form of simple fluoride and/or fluorosilicate.
- A method according to one or more of Claims 1 to 5, characterised in that the metal surfaces are brought into contact with a phosphating solution which is free of zinc.
- A method according to one or more of Claims 1 to 6, characterised in that the metal surfaces are brought into contact with a phosphating solution which is at 40 to 80°C.
- A method according to Claim 7, characterised in that the metal surfaces are brought into contact with a phosphating solution which is at 60 to 70°C.
- A method according to one or more of Claims 1 to 8, characterised in that the metal surfaces are brought into contact with the phosphating solution for a period of 2 to 15 minutes.
- A method according to Claim 9, characterised in that the metal surfaces are brought into contact with the phosphating solution for a period of 4 to 10 minutes.
- A method according to one or more of Claims 1 to 10, characterised in that the metal surfaces are brought into contact with the phosphating solution such that a phosphate layer weight of 1.0 to 2.0 g/m2 results.
- A method according to one or more of Claims 1 to 11, characterised in that the metal surfaces are pickled in sulphuric acid before contact with the phosphating solution.
- A method according to Claim 12, characterised in that the metal surfaces are pickled such that the removal of metal is 2 to 10 g/m2.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4429936A DE4429936A1 (en) | 1994-08-24 | 1994-08-24 | Preparation of metal surfaces for enamelling |
| DE4429936 | 1994-08-24 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0698675A1 EP0698675A1 (en) | 1996-02-28 |
| EP0698675B1 true EP0698675B1 (en) | 1997-10-15 |
Family
ID=6526387
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP95112122A Expired - Lifetime EP0698675B1 (en) | 1994-08-24 | 1995-08-02 | Preparing metal surfaces for enamelling |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US5688340A (en) |
| EP (1) | EP0698675B1 (en) |
| DE (2) | DE4429936A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2374088A (en) * | 2001-03-29 | 2002-10-09 | Macdermid Plc | Conversion treatment of zinc and zinc alloy surfaces |
| AR060509A1 (en) * | 2006-04-13 | 2008-06-25 | Sherwin Williams Co | PIGMENTATION AND COATING COMPOSITION ABLE TO INHIBIT CORROSION OF SUBSTRATES |
| US20080314479A1 (en) * | 2007-06-07 | 2008-12-25 | Henkel Ag & Co. Kgaa | High manganese cobalt-modified zinc phosphate conversion coating |
| CN102719820A (en) * | 2012-06-21 | 2012-10-10 | 大连三达奥克化学股份有限公司 | Single-tank discharge-free comprehensive treating agent before spray coating of long type welded steel pipe and preparation method |
| CN102808172B (en) * | 2012-08-24 | 2014-04-02 | 安徽启明表面技术有限公司 | Universal environment-friendly non-phosphorus phosphating solution |
| EP3231894A1 (en) * | 2016-04-12 | 2017-10-18 | Prince Belgium BVBA | Inorganic primer for steel enamelling |
| DE102021201881A1 (en) * | 2021-02-26 | 2022-09-01 | BSH Hausgeräte GmbH | METHOD OF MAKING AN ENAMELLED STEEL COMPONENT, ENAMELLED STEEL COMPONENT, AND USE THEREOF |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE547657A (en) | 1953-04-17 | |||
| JPS5140342A (en) * | 1974-10-04 | 1976-04-05 | Nippon Packaging Kk | Tetsukonokaseishoriho |
| DE2905535A1 (en) * | 1979-02-14 | 1980-09-04 | Metallgesellschaft Ag | METHOD FOR SURFACE TREATMENT OF METALS |
| GB8527833D0 (en) | 1985-11-12 | 1985-12-18 | Pyrene Chemicals Services Ltd | Phosphate coating of metals |
| GB2259920A (en) * | 1991-09-10 | 1993-03-31 | Gibson Chem Ltd | Surface conversion coating solution based on molybdenum and phosphate compounds |
-
1994
- 1994-08-24 DE DE4429936A patent/DE4429936A1/en not_active Withdrawn
-
1995
- 1995-08-02 EP EP95112122A patent/EP0698675B1/en not_active Expired - Lifetime
- 1995-08-02 DE DE59500801T patent/DE59500801D1/en not_active Expired - Lifetime
- 1995-08-22 US US08/517,816 patent/US5688340A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE4429936A1 (en) | 1996-02-29 |
| DE59500801D1 (en) | 1997-11-20 |
| US5688340A (en) | 1997-11-18 |
| EP0698675A1 (en) | 1996-02-28 |
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