EP0287133B1 - Phosphating treatment before electrophoretic dip painting - Google Patents
Phosphating treatment before electrophoretic dip painting Download PDFInfo
- Publication number
- EP0287133B1 EP0287133B1 EP88200219A EP88200219A EP0287133B1 EP 0287133 B1 EP0287133 B1 EP 0287133B1 EP 88200219 A EP88200219 A EP 88200219A EP 88200219 A EP88200219 A EP 88200219A EP 0287133 B1 EP0287133 B1 EP 0287133B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- workpieces
- phosphating solution
- contacted
- process according
- phosphating
- 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
- 238000010422 painting Methods 0.000 title claims description 4
- 239000000243 solution Substances 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 34
- 239000011701 zinc Substances 0.000 claims description 18
- 229910019142 PO4 Inorganic materials 0.000 claims description 17
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 17
- 239000010452 phosphate Substances 0.000 claims description 17
- 229910000831 Steel Inorganic materials 0.000 claims description 15
- 239000010959 steel Substances 0.000 claims description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 14
- 229910052725 zinc Inorganic materials 0.000 claims description 13
- 239000002253 acid Substances 0.000 claims description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 10
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 8
- 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
- XTEGARKTQYYJKE-UHFFFAOYSA-M Chlorate Chemical compound [O-]Cl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-M 0.000 claims description 6
- 229910001335 Galvanized steel Inorganic materials 0.000 claims description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 6
- 239000008397 galvanized steel Substances 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- AVXURJPOCDRRFD-UHFFFAOYSA-N Hydroxylamine Chemical compound ON AVXURJPOCDRRFD-UHFFFAOYSA-N 0.000 claims description 5
- 238000007654 immersion Methods 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 4
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 4
- JUWGUJSXVOBPHP-UHFFFAOYSA-B titanium(4+);tetraphosphate Chemical compound [Ti+4].[Ti+4].[Ti+4].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O JUWGUJSXVOBPHP-UHFFFAOYSA-B 0.000 claims description 4
- ONMOULMPIIOVTQ-UHFFFAOYSA-M 3-Nitrobenzene sulphonate Chemical compound [O-][N+](=O)C1=CC=CC(S([O-])(=O)=O)=C1 ONMOULMPIIOVTQ-UHFFFAOYSA-M 0.000 claims description 3
- 229910052749 magnesium Inorganic materials 0.000 claims description 3
- 239000011777 magnesium Substances 0.000 claims description 3
- 229910052748 manganese Inorganic materials 0.000 claims description 3
- 239000011572 manganese Substances 0.000 claims description 3
- -1 peroxide compounds Chemical class 0.000 claims description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 2
- 229910004074 SiF6 Inorganic materials 0.000 claims description 2
- FMRLDPWIRHBCCC-UHFFFAOYSA-L Zinc carbonate Chemical compound [Zn+2].[O-]C([O-])=O FMRLDPWIRHBCCC-UHFFFAOYSA-L 0.000 claims description 2
- 239000007864 aqueous solution Substances 0.000 claims description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 229910017052 cobalt Inorganic materials 0.000 claims description 2
- 239000010941 cobalt Substances 0.000 claims description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 2
- 238000007598 dipping method Methods 0.000 claims description 2
- 239000007789 gas Substances 0.000 claims description 2
- FEWJPZIEWOKRBE-LWMBPPNESA-N levotartaric acid Chemical compound OC(=O)[C@@H](O)[C@H](O)C(O)=O FEWJPZIEWOKRBE-LWMBPPNESA-N 0.000 claims description 2
- 239000011656 manganese carbonate Substances 0.000 claims description 2
- 235000006748 manganese carbonate Nutrition 0.000 claims description 2
- 229940093474 manganese carbonate Drugs 0.000 claims description 2
- 229910000016 manganese(II) carbonate Inorganic materials 0.000 claims description 2
- XMWCXZJXESXBBY-UHFFFAOYSA-L manganese(ii) carbonate Chemical compound [Mn+2].[O-]C([O-])=O XMWCXZJXESXBBY-UHFFFAOYSA-L 0.000 claims description 2
- 239000001301 oxygen Substances 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims description 2
- 239000011667 zinc carbonate Substances 0.000 claims description 2
- 235000004416 zinc carbonate Nutrition 0.000 claims description 2
- 229910000010 zinc carbonate Inorganic materials 0.000 claims description 2
- 239000011787 zinc oxide Substances 0.000 claims description 2
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 claims description 2
- 229910000165 zinc phosphate Inorganic materials 0.000 claims description 2
- 229910002547 FeII Inorganic materials 0.000 claims 2
- 238000002360 preparation method Methods 0.000 claims 2
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 claims 1
- 229910000399 iron(III) phosphate Inorganic materials 0.000 claims 1
- 239000000126 substance Substances 0.000 claims 1
- 239000010410 layer Substances 0.000 description 24
- 230000015572 biosynthetic process Effects 0.000 description 10
- 238000004070 electrodeposition Methods 0.000 description 9
- 239000003973 paint Substances 0.000 description 6
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 3
- 150000001768 cations Chemical class 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 239000010802 sludge Substances 0.000 description 3
- 238000005507 spraying Methods 0.000 description 3
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 2
- 238000007792 addition Methods 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 230000009189 diving Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- KJFMBFZCATUALV-UHFFFAOYSA-N phenolphthalein Chemical compound C1=CC(O)=CC=C1C1(C=2C=CC(O)=CC=2)C2=CC=CC=C2C(=O)O1 KJFMBFZCATUALV-UHFFFAOYSA-N 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- FHIDNBAQOFJWCA-UAKXSSHOSA-N 5-fluorouridine Chemical compound O[C@@H]1[C@H](O)[C@@H](CO)O[C@H]1N1C(=O)NC(=O)C(F)=C1 FHIDNBAQOFJWCA-UAKXSSHOSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000011260 aqueous acid Substances 0.000 description 1
- 239000007900 aqueous suspension Substances 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005237 degreasing agent Methods 0.000 description 1
- BNIILDVGGAEEIG-UHFFFAOYSA-L disodium hydrogen phosphate Chemical compound [Na+].[Na+].OP([O-])([O-])=O BNIILDVGGAEEIG-UHFFFAOYSA-L 0.000 description 1
- 229910000397 disodium phosphate Inorganic materials 0.000 description 1
- 235000019800 disodium phosphate Nutrition 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- 239000004922 lacquer Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- JCYPECIVGRXBMO-FOCLMDBBSA-N methyl yellow Chemical compound C1=CC(N(C)C)=CC=C1\N=N\C1=CC=CC=C1 JCYPECIVGRXBMO-FOCLMDBBSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- FQENQNTWSFEDLI-UHFFFAOYSA-J sodium diphosphate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]P([O-])(=O)OP([O-])([O-])=O FQENQNTWSFEDLI-UHFFFAOYSA-J 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- IIACRCGMVDHOTQ-UHFFFAOYSA-N sulfamic acid Chemical compound NS(O)(=O)=O IIACRCGMVDHOTQ-UHFFFAOYSA-N 0.000 description 1
- 235000019818 tetrasodium diphosphate Nutrition 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 238000003466 welding 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
- C23C22/34—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 fluorides or complex fluorides
- C23C22/36—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 fluorides or complex fluorides containing also phosphates
- C23C22/362—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 fluorides or complex fluorides containing also phosphates containing also zinc cations
-
- 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
- C23C22/12—Orthophosphates containing zinc cations
- C23C22/13—Orthophosphates containing zinc cations containing also nitrate or nitrite anions
-
- 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
- C23C22/18—Orthophosphates containing manganese cations
- C23C22/182—Orthophosphates containing manganese cations containing also zinc cations
Definitions
- the invention relates to a method for phosphating workpieces made of steel or partially galvanized steel, in which the cleaned and rinsed workpieces are first activated with an aqueous, weakly alkaline solution containing titanium phosphate and then with an aqueous acidic, NO3, fur and zinc phosphate-containing phosphating solution by immersion treated and its application to the pretreatment for cathodic electrocoating.
- the object of the invention is to provide a method for the phosphating of steel or partially galvanized steel which provides uniformly covering phosphate layers and is particularly well suited as a pretreatment for electrocoating.
- the method of the type mentioned according to the invention is designed in such a way that the workpieces are brought into contact with a phosphating solution at a temperature of 40 to 60 ° C. for the pretreatment for the electrocoating 1.8 to 5 g / l Zn 0.1 to 7 g / l Fe (II) 8 to 25 g / l P2O5 5 to 30 g / l NO3 contains and in which the ratio of free acid to total acid is set to 0.04 to 0.07.
- the method according to the invention is used to treat steel, e.g. of cold-rolled strip and sheet made of soft, unalloyed steels as well as of high-strength cold-rolled thin sheets made of phosphorous steels, micro-alloyed steels and dual-phase steels.
- the galvanizing layers on galvanized steel include e.g. those produced on the hot-dip path, based on Zn, Zn + Fe, Zn + Al, Zn + Al + Si, and those obtained on the electrolytic path based on Zn, Zn + Ni, Zn + Fe.
- the method according to the invention can be applied to workpieces of various types and shapes, ie flat parts, deep-drawn parts, welding, folding, flanging and adhesive constructions.
- workpieces of various types and shapes ie flat parts, deep-drawn parts, welding, folding, flanging and adhesive constructions.
- adequate ventilation and outflow of the liquid must be ensured.
- Typical workpieces of complex shape and with a wide variety of materials are automobile bodies.
- the workpieces are first cleaned in the usual way, for example with alkaline degreasing agents, and then rinsed in water. This is followed by treatment in an aqueous, slightly alkaline solution in which activating titanium phosphate is finely dispersed.
- Phosphating takes place in the temperature range from 40 to 60 ° C. Below this temperature, the phosphating process becomes too slow to form opaque phosphate layers in reasonable times. Above 60 ° C, energy losses rise sharply and there is an increasing risk of disruptive drying and incrustation.
- the phosphating process according to the invention belongs to the group of processes on the "iron side” and is therefore characterized by comparatively low sludge formation.
- the iron (II) concentration can be below 0.1 g / l. After a few throughputs, however, it quickly reaches the area according to the invention as a result of the pickling removal taking place on the steel.
- the ratio of free acid to total acid is of great importance for the implementation of the method according to the invention. Below 0.04, valuable components of the phosphating solution are lost due to increasing sludge formation. Above 0.07, the rate of phosphating drops sharply.
- the setting of the optimal ratio is carried out by adjusting the concentration of the bath components, if necessary with the use of further cations, e.g. of Na, K, NH4, or other anions, e.g. of Cl, SO4.
- the workpieces are brought into contact with a phosphating solution which contains a maximum of 3 g / l Zn and preferably 0.5 to 5 g / l Fe (II).
- Additional layers can be modified to modify the layer formation divalent cations, for example from the group Ca, Co, Cu, Mg, Mn, Ni, are added to the phosphating solution.
- the workpieces are preferably brought into contact with a phosphating solution which additionally contains manganese in an amount of up to 3 g / l or magnesium in an amount of up to 3 g / l.
- a phosphating solution which additionally contains manganese in an amount of up to 3 g / l or magnesium in an amount of up to 3 g / l.
- cobalt is added, up to 0.3 g / l and nickel up to 0.15 g / l are preferred.
- streaky phosphate layers can be formed on steel.
- Another expedient embodiment of the invention consists in bringing the workpieces into contact with a phosphating solution which contains up to 3 g / l, preferably at least 0.3 g / l, of hydroxylamine.
- concentration of Ni can be increased to 0.5 g / l if at least 0.3 g / l of hydroxylamine are present at the same time.
- Hydroxylamine has an accelerating effect on the phosphating process.
- the workpieces are brought into contact with a phosphating solution containing up to 3 g / l SiF6 and / or up to 3 g / l BF4 and / or up to 1.5 g / l F contains.
- Additions of preferably up to 3 g / l tartaric acid and / or citric acid serve to reduce the weight per unit area of the phosphate layers and to further accelerate the layer formation.
- phosphating solutions which contain up to 0.5 g / l, preferably 0.05 to 0.35 g / l, of m-nitrobenzenesulfonate.
- m-Nitrobenzenesulfonate causes a strong acceleration of the phosphating with a simultaneous significant reduction in the thickness of the phosphate.
- the contact of the phosphating solution with oxygen-containing gas and the addition of chlorate and / or peroxide compounds can be used for this oxidation.
- the phosphating process according to the invention can also do so be modified that the immersion in the phosphating solution is preceded by a spraying with the phosphating solution and / or is connected.
- the diving times are usually in the range from 2 to 5 minutes, while the pre-spraying and / or post-spraying takes from a few seconds to about 0.5 minutes.
- the phosphating process according to the invention is carried out in such a way that phosphate layers with a basis weight of 1 to 5 g / m2 are produced. In this way, optimal corrosion protection is combined with good bending adhesion of the paint coatings.
- the layers formed by the process according to the invention are suitable as a primer for anodic and cathodic electrocoating materials. Particularly favorable results are achieved if the process is used for pretreatment for cathodic electrocoating and lacquer film thicknesses in the range from approximately 15 to 40 ⁇ m are to be achieved.
- the electrocoat layers can serve as a base coat for further layers of paint or as single-layer paints.
- Sheets of body steel and galvanized steel were degreased with an alkaline cleaner, rinsed in water, with an aqueous suspension of about 50 mg / l titanium phosphate in an aqueous solution of 1 g / l disodium phosphate and 0.25 g / l tetrasodium pyrophosphate by immersion at 40 ° C for 1 min and then in the phosphating solutions 1 to 6 listed in the table phosphated at 55 ° C in diving.
- a minimum phosphating time of 2 to 3 minutes was found on steel and less than 1 minute on galvanized steel.
- the treatment time in the phosphating bath is defined as the minimum phosphating time, which is necessary for the formation of a visually uniformly covering phosphate layer.
- the layer weight for steel was between 3.6 and 4.3 g / m2, for zinc between 2.2 and 3.0 g / m2.
- Free acid (total acid) is defined as the amount of ml n / 10 NaOH required to neutralize 10 ml bath sample against dimethyl yellow (phenolphthalein). The ratio of free acid to total acid was (0.054 to 0.063): 1.
- rinsing was carried out with water, passivated with a rinse solution containing chromium, rinsed with demineralized water and then electrodeposited cathodically.
Landscapes
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (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 Phosphatierung von Werkstücken aus Stahl oder teilweise verzinktem Stahl , bei dem die gereinigten und gespülten Werkstücke zunächst mit einer Titanphosphat enthaltenden wäßrigen, schwach alkalischen Lösung aktiviert und anschließend mit einer wäßrigen sauren, NO₃, Fell und Zinkphosphat enthaltenden Phosphatierungslösung im Tauchverfahren behandelt werden sowie dessen Anwendung auf die Vorbehandlung für die kathodische Elektrotauchlackierung.The invention relates to a method for phosphating workpieces made of steel or partially galvanized steel, in which the cleaned and rinsed workpieces are first activated with an aqueous, weakly alkaline solution containing titanium phosphate and then with an aqueous acidic, NO₃, fur and zinc phosphate-containing phosphating solution by immersion treated and its application to the pretreatment for cathodic electrocoating.
Es ist bekannt, Stahl mit wäßrigen sauren Phosphatierungslösungen auf Basis Zink/Eisen(II)/Nitrat/Phosphat im Tauchen zu behandeln und anschließend zu lackieren (EP-A-45110). Versucht man, dieses Verfahren als Vorbehandlung für die Elektrotauchlackierung einzusetzen, ergeben sich jedoch erhebliche Mängel. So führt die schwankende Phosphatschichtdicke des bekannten Verfahrens zur Ausbildung ungleichmäßig dicker Elektrotauchlackschichten, die zum Teil mit Schlieren, Läufern und Kratern durchsetzt sind. Ferner entspricht der Korrosionsschutz häufig nicht den gestellten Anforderungen.It is known to treat steel with aqueous acid phosphating solutions based on zinc / iron (II) / nitrate / phosphate in dipping and then to paint (EP-A-45110). Attempting to use this process as a pretreatment for electrocoating, however, results in considerable shortcomings. The fluctuating phosphate layer thickness of the known method leads to the formation of unevenly thick electrocoat layers, which are partially interspersed with streaks, runners and craters. Furthermore, the corrosion protection often does not meet the requirements.
Aufgabe der Erfindung ist es, ein Verfahren für die Phosphatierung von Stahl oder teilweise verzinktem Stahl bereitzustellen, das gleichmäßig deckende Phosphatschichten liefert und besonders gut als Vorbehandlung für die Elektrotauchlackierung geeignet ist.The object of the invention is to provide a method for the phosphating of steel or partially galvanized steel which provides uniformly covering phosphate layers and is particularly well suited as a pretreatment for electrocoating.
Die Aufgabe wird gelöst, indem das Verfahren der eingangs genannten Art entsprechend der Erfindung derart ausgestaltet wird, daß man zwecks Vorbehandlung für die Elektrotauchlackierung die Werkstücke bei einer Temperatur von 40 bis 60°C mit einer Phosphatierungslösung in Kontakt bringt, die
1,8 bis 5 g/l Zn
0,1 bis 7 g/l Fe(II)
8 bis 25 g/l P₂O₅
5 bis 30 g/l NO₃
enthält und in der das Verhältnis von Freier Säure zu Gesamtsäure auf 0,04 bis 0,07 eingestellt ist.The object is achieved in that the method of the type mentioned according to the invention is designed in such a way that the workpieces are brought into contact with a phosphating solution at a temperature of 40 to 60 ° C. for the pretreatment for the electrocoating
1.8 to 5 g / l Zn
0.1 to 7 g / l Fe (II)
8 to 25 g / l P₂O₅
5 to 30 g / l NO₃
contains and in which the ratio of free acid to total acid is set to 0.04 to 0.07.
Das erfindungsgemäße Verfahren dient der Behandlung von Stahl, z.B. von kaltgewalztem Band und Blech aus weichen, unlegierten Stählen sowie von höherfesten kaltgewalzten Feinblechen aus aufgephosphorten Stählen, mikrolegierten Stählen und Dual-Phase-Stählen. Die Verzinkungsschichten auf verzinktem Stahl umfassen z.B. die auf dem Schmelztauchwege erzeugten, auf Basis Zn, Zn + Fe, Zn + Al, Zn + Al + Si sowie die auf elektrolytischem Wege erhaltenen auf Basis Zn, Zn + Ni, Zn + Fe.The method according to the invention is used to treat steel, e.g. of cold-rolled strip and sheet made of soft, unalloyed steels as well as of high-strength cold-rolled thin sheets made of phosphorous steels, micro-alloyed steels and dual-phase steels. The galvanizing layers on galvanized steel include e.g. those produced on the hot-dip path, based on Zn, Zn + Fe, Zn + Al, Zn + Al + Si, and those obtained on the electrolytic path based on Zn, Zn + Ni, Zn + Fe.
Das erfindungsgemäße Verfahren kann auf Werkstücke unterschiedlichster Art und Form, d.h. Flachzeug, Tiefziehteile, Schweiß-, Falz-, Bördel- und Klebkonstruktionen angewendet werden. Um bei Hohlkörpern eine gute Behandlung der Innenflächen zu erzielen, muß für ausreichende Entlüftung und Ausfluß der Flüssigkeit gesorgt werden. Typische Werkstücke komplexer Form und mit unterschiedlichsten Materialien sind Automobilkarosserien.The method according to the invention can be applied to workpieces of various types and shapes, ie flat parts, deep-drawn parts, welding, folding, flanging and adhesive constructions. In order to achieve a good treatment of the inner surfaces in the case of hollow bodies, adequate ventilation and outflow of the liquid must be ensured. Typical workpieces of complex shape and with a wide variety of materials are automobile bodies.
Die Werkstücke werden zunächst in üblicher Weise, beispielsweise mit alkalischen Entfettungsmitteln, gereinigt und anschließend in Wasser gespült. Hieran schließt sich die Behandlung in einer wäßrigen, leicht alkalischen Lösung, in der aktivierend wirkendes Titanphosphat feinst dispergiert ist.The workpieces are first cleaned in the usual way, for example with alkaline degreasing agents, and then rinsed in water. This is followed by treatment in an aqueous, slightly alkaline solution in which activating titanium phosphate is finely dispersed.
Die Phosphatierung erfolgt im Temperaturbereich von 40 bis 60°C. Unterhalb dieser Temperatur wird der Phosphatiervorgang zu langsam, um deckende Phosphatschichten in vertretbaren Zeiten auszubilden. Oberhalb 60°C steigen die Energieverluste stark an und es besteht zunehmend die Gefahr von störenden Antrocknungen und Verkrustungen.Phosphating takes place in the temperature range from 40 to 60 ° C. Below this temperature, the phosphating process becomes too slow to form opaque phosphate layers in reasonable times. Above 60 ° C, energy losses rise sharply and there is an increasing risk of disruptive drying and incrustation.
Das erfindungsgemäße Phosphatierverfahren gehört in die Gruppe der Verfahren auf der "Eisenseite" und zeichnet sich damit durch vergleichsweise geringe Schlammbildung aus. Beim Start der Bäder kann die Eisen(II)-Konzentration unter 0,1 g/l liegen. Nach wenigen Durchsätzen gelangt sie jedoch infolge des am Stahl stattfindenden Beizabtrages schnell in den erfindungsgemäßen Bereich.The phosphating process according to the invention belongs to the group of processes on the "iron side" and is therefore characterized by comparatively low sludge formation. At the start of the baths, the iron (II) concentration can be below 0.1 g / l. After a few throughputs, however, it quickly reaches the area according to the invention as a result of the pickling removal taking place on the steel.
Die Einhaltung der erfindungswesentlichen Konzentrationsbereiche für Zn, Fe(II), P₂O₅ und NO₃ ist die Voraussetzung dafür, optimal für die anschließende Elektrotauchlackierung geeignete Phosphatschichten zu erzeugen. Bei Unterschreitung von 1,8 g/l Zn werden z.B. nur noch unvollständig deckende Phosphatschichten auf Stahl erzeugt. Oberhalb von 5 g/l Zn werden die Phosphatschichten zu dick, um noch eine einwandfreie Lackierung zu ermöglichen. Oberhalb von 7 g/l Fe(II) nimmt die Qualität der Phosphatschichten im Hinblick auf die nachfolgende Elektrotauchbehandlung deutlich ab. Unterhalb von 8 g/l P₂O₅ reicht der Phosphatgehalt für eine ordnungsgemäße Phosphatierung nicht mehr aus, während eine Überschreitung von 25 g/l P₂O₅ keine weiteren technischen Vorteile mehr erbringt. Bei NO₃-Konzentrationen unter 5 g/l fehlt es den Bädern an der notwendigen Beschleunigung der Phosphatschichtausbildung. Oberhalb 30 g/l NO₃ findet keine weitere auswertbare Zunahme der Schichtbildungsgeschwindigkeit mehr statt.Compliance with the concentration ranges for Zn, Fe (II), P₂O₅ and NO₃ which is essential to the invention is the prerequisite for producing phosphate layers which are optimally suitable for the subsequent electrocoating. If the amount falls below 1.8 g / l Zn, for example, only incompletely covering phosphate layers are produced on steel. Above 5 g / l Zn, the phosphate layers become too thick to allow perfect painting. Above 7 g / l Fe (II) increases the quality of the phosphate layers with regard to the subsequent electrodeposition treatment significantly. Below 8 g / l P₂O₅ the phosphate content is no longer sufficient for proper phosphating, while exceeding 25 g / l P₂O₅ no longer provides any further technical advantages. At NO₃ concentrations below 5 g / l, the baths lack the necessary acceleration of the phosphate layer formation. Above 30 g / l NO₃ there is no further evaluable increase in the layer formation rate.
Von großer Bedeutung für die Durchführung des erfindungsgemäßen Verfahrens ist das Verhältnis von Freier Säure zu Gesamtsäure. Unter 0,04 gehen wertvolle Bestandteile der Phosphatierungslösung durch zunehmende Schlammbildung verloren. Oberhalb 0,07 nimmt die Phosphatiergeschwindigkeit stark ab. Die Einstellung des optimalen Verhältnisses wird durch eine Konzentrationsabstimmung der Badkomponenten, gegebenenfalls unter Mitverwendung weiterer Kationen, z.B. von Na, K, NH₄, oder weiteren Anionen, z.B. von Cl, SO₄, erzielt.The ratio of free acid to total acid is of great importance for the implementation of the method according to the invention. Below 0.04, valuable components of the phosphating solution are lost due to increasing sludge formation. Above 0.07, the rate of phosphating drops sharply. The setting of the optimal ratio is carried out by adjusting the concentration of the bath components, if necessary with the use of further cations, e.g. of Na, K, NH₄, or other anions, e.g. of Cl, SO₄.
Besonders günstige Ergebnisse bezüglich der nachfolgenden Elektrotauchlackierung werden erzielt, wenn entsprechend einer bevorzugten Ausgestaltung der Erfindung die Werkstücke mit einer Phosphatierungslösung in Kontakt gebracht werden, die maximal 3 g/l Zn und vorzugsweise 0,5 bis 5 g/l Fe(II) enthält.Particularly favorable results with regard to the subsequent electrocoating are achieved if, according to a preferred embodiment of the invention, the workpieces are brought into contact with a phosphating solution which contains a maximum of 3 g / l Zn and preferably 0.5 to 5 g / l Fe (II).
Zur Modifikation der Schichtbildung können weitere zweiwertige Kationen, z.B. aus der Gruppe Ca, Co, Cu, Mg, Mn, Ni, der Phosphatierungslösung zugesetzt werden. Vorzugsweise werden die Werkstücke mit einer Phosphatierungslösung in Kontakt gebracht, die zusätzlich Mangan in einer Menge bis zu 3 g/l bzw. Magnesium in einer Menge bis zu 3 g/l enthält. Bei Zugabe von Cobalt sind bis 0,3 g/l und von Nickel bis 0,15 g/l bevorzugt. Bei Gehalten über 0,3 g/l Co bzw. über 0,15 g/l Ni können streifige Phosphatschichten auf Stahl ausgebildet werden.Additional layers can be modified to modify the layer formation divalent cations, for example from the group Ca, Co, Cu, Mg, Mn, Ni, are added to the phosphating solution. The workpieces are preferably brought into contact with a phosphating solution which additionally contains manganese in an amount of up to 3 g / l or magnesium in an amount of up to 3 g / l. When cobalt is added, up to 0.3 g / l and nickel up to 0.15 g / l are preferred. At levels above 0.3 g / l Co or above 0.15 g / l Ni, streaky phosphate layers can be formed on steel.
Eine weitere zweckmäßige Ausführungsform der Erfindung besteht darin, die Werkstücke mit einer Phosphatierungslösung in Kontakt zu bringen, die bis zu 3 g/l, vorzugsweise mindestens 0,3 g/l, Hydroxylamin enthält. In diesem Fall kann die Konzentration von Ni auf 0,5 g/l erhöht werden, wenn gleichzeitig mindestens 0,3 g/l Hydroxylamin anwesend sind. Hydroxylamin wirkt sich beschleunigend auf den Phosphatiervorgang aus.Another expedient embodiment of the invention consists in bringing the workpieces into contact with a phosphating solution which contains up to 3 g / l, preferably at least 0.3 g / l, of hydroxylamine. In this case the concentration of Ni can be increased to 0.5 g / l if at least 0.3 g / l of hydroxylamine are present at the same time. Hydroxylamine has an accelerating effect on the phosphating process.
Zur Erhöhung der Aggressivität der Phosphatierungslösung, zur Erhöhung der Phosphatiergeschwindigkeit und zur Optimierung der Schichtbildung auf aluminiumhaltigen Zinkoberflächen werden gemäß einer weiteren vorteilhaften Ausführungsform der Erfindung die Werkstücke mit einer Phosphatierungslösung in Kontakt gebracht, die bis zu 3 g/l SiF₆ und/oder bis zu 3 g/l BF₄ und/oder bis zu 1,5 g/l F enthält.In order to increase the aggressiveness of the phosphating solution, to increase the rate of phosphating and to optimize the layer formation on aluminum-containing zinc surfaces, according to a further advantageous embodiment of the invention, the workpieces are brought into contact with a phosphating solution containing up to 3 g / l SiF₆ and / or up to 3 g / l BF₄ and / or up to 1.5 g / l F contains.
Zusätze von vorzugsweise bis zu 3 g/l Weinsäure und/oder Zitronensäure dienen dazu, das Flächengewicht der Phosphatschichten herabzusetzen und die Schichtbildung weiter zu beschleunigen.Additions of preferably up to 3 g / l tartaric acid and / or citric acid serve to reduce the weight per unit area of the phosphate layers and to further accelerate the layer formation.
Weiterhin ist es vorteilhaft, Phosphatierungslösungen einzusetzen, die bis zu 0,5 g/l, vorzugsweise 0,05 bis 0,35 g/l m-Nitrobenzolsulfonat enthalten. m-Nitrobenzolsulfonat bewirkt eine starke Beschleunigung der Phosphatierung bei gleichzeitiger deutlicher Herabsetzung der Phosphatschichtdicke.It is also advantageous to use phosphating solutions which contain up to 0.5 g / l, preferably 0.05 to 0.35 g / l, of m-nitrobenzenesulfonate. m-Nitrobenzenesulfonate causes a strong acceleration of the phosphating with a simultaneous significant reduction in the thickness of the phosphate.
Um zu vermeiden, daß die Phosphatierbäder von der Eisenseite durch autokatalytische Nitritbildung auf die Nitritseite kommen, werden den Bädern vorzugsweise Nitrit zerstörende Verbindungen, z.B. Harnstoff oder Amidosulfosäure, zugesetzt.In order to avoid that the phosphating baths come from the iron side to the nitrite side by autocatalytic nitrite formation, compounds which destroy the nitrite, e.g. Urea or amidosulfonic acid added.
Um einen Anstieg der Eisen(II)-Konzentration über die gewünschte Konzentration hinaus zu vermeiden, ist es zweckmäßig, einen Teil des durch Beizangriff in Lösung gegangenen Eisen(II) zu Eisen(III) zu oxidieren und damit in Form von schwerlöslichem Eisen(III)-phosphat-Schlamm auszufällen. Nach bevorzugten Ausgestaltungen der Erfindung können für diese Oxidation der Kontakt der Phosphatierungslösung mit sauerstoffhaltigem Gas sowie der Zusatz von Chlorat und/oder Peroxidverbindungen dienen.In order to avoid an increase in the iron (II) concentration beyond the desired concentration, it is expedient to oxidize part of the iron (II) which has dissolved in solution by pickling to iron (III) and thus in the form of poorly soluble iron (III ) precipitate phosphate sludge. According to preferred embodiments of the invention, the contact of the phosphating solution with oxygen-containing gas and the addition of chlorate and / or peroxide compounds can be used for this oxidation.
Zur Herabsetzung der Freien Säure in den Phosphatierbädern können z.B. Alkalihydroxide und Karbonate zugesetzt werden. Besonders vorteilhaft ist die Verwendung von Zinkoxid, Zinkkarbonat und/oder Mangankarbonat, mit dem zusätzlich schichtbildende Kationen in die Phosphatierungslösung eingebracht werden.To reduce the free acidity in the phosphating baths e.g. Alkali hydroxides and carbonates are added. The use of zinc oxide, zinc carbonate and / or manganese carbonate, with which additional layer-forming cations are introduced into the phosphating solution, is particularly advantageous.
Das erfindungsgemäße Phosphatierverfahren kann außerdem so modifiziert werden, daß dem Tauchen in die Phosphatierungslösung ein Spritzen mit der Phosphatierungslösung vorausgeht und/oder angeschlossen wird. Üblicherweise liegen die Tauchzeiten im Bereich von 2 bis 5 min, während das Vor- und/oder Nachspritzen sich auf wenige Sekunden bis etwa 0,5 min beläuft.The phosphating process according to the invention can also do so be modified that the immersion in the phosphating solution is preceded by a spraying with the phosphating solution and / or is connected. The diving times are usually in the range from 2 to 5 minutes, while the pre-spraying and / or post-spraying takes from a few seconds to about 0.5 minutes.
Gemäß einer vorteilhaften Ausführungform wird das erfindungsgemäße Phosphatierverfahren derart geführt, daß Phosphatschichten mit einem Flächengewicht von 1 bis 5 g/m² erzeugt werden. Hierdruch wird optimaler Korrosionsschutz mit einer guten Biegehaftung der Lacküberzüge verbunden.According to an advantageous embodiment, the phosphating process according to the invention is carried out in such a way that phosphate layers with a basis weight of 1 to 5 g / m² are produced. In this way, optimal corrosion protection is combined with good bending adhesion of the paint coatings.
Die mit dem erfindungsgemäßen Verfahren ausgebildeten Schichten sind als Haftgrund für anodische und kathodische Elektrotauchlacke geeignet. Besonders günstige Ergebnisse werden erzielt, wenn das Verfahren zur Vorbehandlung für die kathodische Elektrotauchlackierung dient und hierbei Lackfilmdicken im Bereich von ca. 15 bis 40 µm erzielt werden sollen. Die Elektrotauchlackschichten können als Grundlack für weitere Lackschichten oder auch als Einschichtlacke dienen.The layers formed by the process according to the invention are suitable as a primer for anodic and cathodic electrocoating materials. Particularly favorable results are achieved if the process is used for pretreatment for cathodic electrocoating and lacquer film thicknesses in the range from approximately 15 to 40 μm are to be achieved. The electrocoat layers can serve as a base coat for further layers of paint or as single-layer paints.
Die Erfindung wird anhand der nachfolgenden Beispiele beispielsweise und näher erläutert.The invention is illustrated by the following examples, for example and in more detail.
Bleche aus Karosseriestahl und verzinktem Stahl wurden mit einem alkalischen Reiniger entfettet, in Wasser gespült, mit einer wäßrigen Suspension aus etwa 50 mg/l Titanphosphat in einer wäßrigen Lösung aus 1 g/l Dinatriumphosphat und 0,25 g/l Tetranatriumpyrophosphat durch 1 min Tauchen bei 40°C aktiviert und anschließend in den in der Tabelle angeführten Phosphatierungslösungen 1 bis 6 bei 55°C im Tauchen phosphatiert.Sheets of body steel and galvanized steel were degreased with an alkaline cleaner, rinsed in water, with an aqueous suspension of about 50 mg / l titanium phosphate in an aqueous solution of 1 g / l disodium phosphate and 0.25 g / l tetrasodium pyrophosphate by immersion at 40 ° C for 1 min and then in the phosphating solutions 1 to 6 listed in the table phosphated at 55 ° C in diving.
Auf Stahl wurde eine Mindestphosphatierzeit von 2 bis 3 min, auf verzinktem Stahl von kleiner als 1 min gefunden. Als Mindestphosphatierzeit ist die Behandlungszeit im Phosphatierbad definiert, die zur Ausbildung einer visuell gleichmäßig deckenden Phosphatschicht notwendig ist.A minimum phosphating time of 2 to 3 minutes was found on steel and less than 1 minute on galvanized steel. The treatment time in the phosphating bath is defined as the minimum phosphating time, which is necessary for the formation of a visually uniformly covering phosphate layer.
Das Schichtgewicht lag bei Stahl zwischen 3,6 und 4,3 g/m², bei Zink zwischen 2,2 und 3,0 g/m².The layer weight for steel was between 3.6 and 4.3 g / m², for zinc between 2.2 and 3.0 g / m².
Die Freie Säure (Gesamtsäure) ist definiert als die Menge an ml n/10 NaOH, die zur Neutralisation von 10 ml Badprobe gegen Dimethylgelb (Phenolphthalein) erforderlich ist. Das Verhältnis von Freier Säure zu Gesamtsäure betrug (0,054 bis 0,063) : 1.Free acid (total acid) is defined as the amount of ml n / 10 NaOH required to neutralize 10 ml bath sample against dimethyl yellow (phenolphthalein). The ratio of free acid to total acid was (0.054 to 0.063): 1.
Nach der Phosphatierung wurde mit Wasser gespült, mit chromhaltiger Nachspüllösung passiviert, mit vollentsalztem Wasser nachgespült und danach kathodisch elektrotauchlackiert.After the phosphating, rinsing was carried out with water, passivated with a rinse solution containing chromium, rinsed with demineralized water and then electrodeposited cathodically.
Es ergaben sich gleichmäßige Lackschichten, die ohne und mit weiterem Lackaufbau eine sehr gute Haftung zum metallischen Untergrund und einen ausgezeichneten Korrosionsschutz zeigten. Diese Qualität war mindestens der ebenbürtig, die mit den bekannten Niedrigzink-Phosphatierverfahren, betrieben mit Chlorat-und/oder Nitrit-Beschleunigung in praktisch Eisen(II)-freien Bädern, erhalten wurden.
Claims (16)
- A process of phosphating workpieces made of steel or partly galvanized steel, wherein the cleaned and rinsed workpieces are first activated with a weakly alkaline aqueous solution which contains titanium phosphate and are subsequently treated with an acid aqueous phosphating solution which contains NO₃, FeII and zinc phosphate, by a dipping process characterized in that the workpieces in preparation for electro-immersion painting are contacted at a temperature from 40 to 60°C with a phosphating solution which contains
1.8 to 5 g/l Zn
0.1 to 7 g/l FeII
8 to 25 g/l P₂O₅
5 to 30 g/l NO₃
and in which the ratio of free acid to total acid is adjusted to 0.04 to 0.07. - A process according to claim 1, characterized in that the workpieces are contacted with a phosphating solution which contains up to 3 g/l zinc and 0.5 to 5 g/l iron(II).
- A process according to claim 1 or 2, characterized in that the workpieces are contacted with a phosphating solution which additionally contains up to 3 g/l manganese.
- A process according to claim 1, 2 or 3, characterized in that the workpieces are contacted with a phosphating solution which additionally contains up to 3 g/l magnesium.
- A process according to claim 1, 2, 3 or 4, characterized in that the workpieces are contacted with a phosphating solution which additionally contains up to 0.3 g/l cobalt and/or up to 0.15 g/l nickel.
- A process according to one or more of the claims 1 to 5, characterized in that the workpieces are contacted with a phosphating solution which contains up to 3 g/l hydroxylamine.
- A process according to one or more of the claims 1 to 6, characterized in that the workpieces are contacted with a phosphating solution which contains at least 0.3 g/l hydroxylamine and up to 0.5 g/l nickel.
- A process according to one or more of the claims 1 to 7, characterized in that the workpieces are contacted with a phosphating solution which contains up to 3 g/l SiF₆ and/or up to 3 g/l BF₄ and/or up to 1.5 g/l F.
- A process according to one or more of the claims 1 to 8, characterized in that the workpieces are contacted with a phosphating solution which contains up to 3 g/l tartaric acid and/or citric acid.
- A process according to one or more of the claims 1 to 9, characterized in that the workpieces are contacted with a phosphating solution which contains up to 0.5 g/l m-nitrobenzene sulfonate.
- A process according to one or more of the claims 1 to 10, characterized in that the workpieces are contacted with a phosphating solution which contains nitrite-destroying substances.
- A process according to one or more of the claims 1 to 11, characterized in that the workpieces are contacted with a phosphating solution in which the content of divalent iron is adjusted in that surplus divalent iron that has entered the phosphating solution is precipitated as iron(III) phosphate by means of oxygen-containing gases and/or chlorate and/or peroxide compounds.
- A process according to one or more of the claims 1 to 12, characterized in that the workpieces are contacted with a phosphating solution in which the content of free acid is adjusted by an addition of zinc oxide, zinc carbonate and/or manganese carbonate.
- A process according to one or more of the claims 1 to 13, characterized in that the workpieces are contacted with sprayed phosphating solution before and/or after the workpieces are dipped into the phosphating solution.
- A process according to one or more of the claims 1 to 14, characterized in that the workpieces are contacted with a phosphating solution so as to apply phosphate coatings having a weight from 1 to 5 g/m².
- The use of the process according to one or more of the claims 1 to 15 in preparation for cathodic electro-immersion painting.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3712339 | 1987-04-11 | ||
| DE19873712339 DE3712339A1 (en) | 1987-04-11 | 1987-04-11 | METHOD FOR PHOSPHATIZING BEFORE ELECTROPLATING |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0287133A1 EP0287133A1 (en) | 1988-10-19 |
| EP0287133B1 true EP0287133B1 (en) | 1992-03-25 |
Family
ID=6325439
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP88200219A Expired - Lifetime EP0287133B1 (en) | 1987-04-11 | 1988-02-09 | Phosphating treatment before electrophoretic dip painting |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0287133B1 (en) |
| JP (1) | JP2674075B2 (en) |
| AU (1) | AU1442788A (en) |
| BR (1) | BR8801679A (en) |
| CA (1) | CA1332910C (en) |
| DE (2) | DE3712339A1 (en) |
| ES (1) | ES2030493T3 (en) |
| GB (1) | GB2204067B (en) |
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|---|---|---|---|---|
| JP2636919B2 (en) * | 1989-01-26 | 1997-08-06 | 日本パーカライジング株式会社 | Lubrication treatment method for cold plastic working of steel |
| JPH0819531B2 (en) * | 1989-03-02 | 1996-02-28 | 日本ペイント株式会社 | Zinc phosphate treatment method for metal surface |
| DE3913089A1 (en) * | 1989-04-21 | 1990-10-25 | Henkel Kgaa | CHLORATE- AND NITRITE-FREE METHOD FOR THE PRODUCTION OF NICKEL- AND MANGANE-CONTAINING ZINC PHOSPHATE LAYERS |
| DE3920296A1 (en) * | 1989-06-21 | 1991-01-10 | Henkel Kgaa | METHOD FOR PRODUCING ZINC PHOSPHATE CONTAINING MANGANE AND MAGNESIUM |
| DE3927614A1 (en) * | 1989-08-22 | 1991-02-28 | Metallgesellschaft Ag | METHOD OF GENERATING PHOSPHATURE SUPPLIES ON METALS |
| US5082511A (en) * | 1989-09-07 | 1992-01-21 | Henkel Corporation | Protective coating processes for zinc coated steel |
| US5261973A (en) * | 1991-07-29 | 1993-11-16 | Henkel Corporation | Zinc phosphate conversion coating and process |
| US5143562A (en) | 1991-11-01 | 1992-09-01 | Henkel Corporation | Broadly applicable phosphate conversion coating composition and process |
| DE4241134A1 (en) * | 1992-12-07 | 1994-06-09 | Henkel Kgaa | Process for phosphating metal surfaces |
| DE4326388A1 (en) * | 1993-08-06 | 1995-02-09 | Metallgesellschaft Ag | Process for the phosphating treatment of one-sided galvanized steel strip |
| DE19541285C2 (en) * | 1995-11-06 | 2003-04-17 | Kluthe Gmbh Chem Werke | Process and means for phosphating metal surfaces |
| US5797987A (en) * | 1995-12-14 | 1998-08-25 | Ppg Industries, Inc. | Zinc phosphate conversion coating compositions and process |
| JPH10204649A (en) * | 1997-01-24 | 1998-08-04 | Nippon Parkerizing Co Ltd | Aqueous phosphate treating solution for metallic surface and its treatment |
| US6179934B1 (en) | 1997-01-24 | 2001-01-30 | Henkel Corporation | Aqueous phosphating composition and process for metal surfaces |
| DE19718891C2 (en) * | 1997-05-03 | 2001-03-15 | Kluthe Gmbh Chem Werke | Process and agent for phosphating aluminum surfaces |
| JPH11264076A (en) * | 1998-01-14 | 1999-09-28 | Nippon Paint Co Ltd | Chemical conversion treatment for low lead ed |
| DE19808755A1 (en) | 1998-03-02 | 1999-09-09 | Henkel Kgaa | Layer weight control for strip phosphating |
| AU1581700A (en) * | 1998-07-21 | 2000-02-28 | Brent International Plc | Nickel-zinc phosphate conversion coatings |
| DE19905479A1 (en) * | 1999-02-10 | 2000-08-17 | Metallgesellschaft Ag | Process for the phosphatisation of zinc or aluminum surfaces |
| JP2001295063A (en) * | 2000-04-10 | 2001-10-26 | Nippon Parkerizing Co Ltd | Method for forming phosphate film to nonferrous metallic material and plated steel sheet |
| JP4992385B2 (en) * | 2006-10-31 | 2012-08-08 | Ｊｆｅスチール株式会社 | Organic resin-coated phosphate-treated zinc-based plated steel sheet and method for producing the same |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL271948A (en) * | 1960-12-02 | |||
| BE635970A (en) * | 1962-11-13 | |||
| DE2240049B2 (en) * | 1972-08-16 | 1977-05-12 | Metallgesellschaft Ag, 6000 Frankfurt | PROCESS FOR THE PRODUCTION OF PHOSPHATE COATINGS ON IRON AND STEEL AND CONCENTRATES FOR THE PRODUCTION AND ADDITION OF THE PHOSPHATIZING SOLUTION USED IN THIS SITE |
| IT975560B (en) * | 1972-10-20 | 1974-08-10 | Sec Accomandita Semplice Fosfa | PROCEDURE FOR PHOSPHATING ON METALLIC SURFACES INTENDED FOR PAINTING ESPECIALLY FOR ELETROPHORESIS AND SOLUTION RELATING TO THIS PROCEDURE |
| GB1408702A (en) * | 1973-02-09 | 1975-10-01 | Pyrene Chemical Services Ltd | Phosphate coating compositions and processes |
| JPS5165041A (en) * | 1974-12-04 | 1976-06-05 | Nippon Packaging Kk | Kinzokuno rinsanenhimakukeiseihoho |
| JPS5811513B2 (en) * | 1979-02-13 | 1983-03-03 | 日本ペイント株式会社 | How to protect metal surfaces |
| GB2080835B (en) * | 1980-07-25 | 1984-08-30 | Pyrene Chemical Services Ltd | Prevention of sludge in phosphating baths |
| DE3245411A1 (en) * | 1982-12-08 | 1984-07-05 | Gerhard Collardin GmbH, 5000 Köln | METHOD FOR PHOSPHATING ELECTROLYTICALLY GALVANIZED METAL GOODS |
| DE3311738A1 (en) * | 1983-03-31 | 1984-10-04 | Metallgesellschaft Ag, 6000 Frankfurt | METHOD FOR PHOSPHATING METAL SURFACES |
| DE3345498A1 (en) * | 1983-12-16 | 1985-06-27 | Metallgesellschaft Ag, 6000 Frankfurt | Process for producing phosphate coatings |
| FR2569203B1 (en) * | 1984-08-16 | 1989-12-22 | Produits Ind Cie Fse | PROCESS FOR THE TREATMENT BY CHEMICAL CONVERSION OF SUBSTRATES IN ZINC OR IN ONE OF ITS ALLOYS, CONCENTRATE AND BATH USED FOR THE IMPLEMENTATION OF THIS PROCESS |
| CA1257527A (en) * | 1984-12-20 | 1989-07-18 | Thomas W. Tull | Cold deformation process employing improved lubrication coating |
-
1987
- 1987-04-11 DE DE19873712339 patent/DE3712339A1/en not_active Withdrawn
-
1988
- 1988-02-09 DE DE8888200219T patent/DE3869455D1/en not_active Expired - Lifetime
- 1988-02-09 EP EP88200219A patent/EP0287133B1/en not_active Expired - Lifetime
- 1988-02-09 ES ES198888200219T patent/ES2030493T3/en not_active Expired - Lifetime
- 1988-03-02 CA CA000560326A patent/CA1332910C/en not_active Expired - Fee Related
- 1988-04-08 BR BR8801679A patent/BR8801679A/en not_active Application Discontinuation
- 1988-04-08 AU AU14427/88A patent/AU1442788A/en not_active Abandoned
- 1988-04-09 JP JP63086291A patent/JP2674075B2/en not_active Expired - Lifetime
- 1988-04-11 GB GB8808478A patent/GB2204067B/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| ES2030493T3 (en) | 1992-11-01 |
| JPS64277A (en) | 1989-01-05 |
| EP0287133A1 (en) | 1988-10-19 |
| DE3869455D1 (en) | 1992-04-30 |
| GB8808478D0 (en) | 1988-05-11 |
| AU1442788A (en) | 1988-10-13 |
| JP2674075B2 (en) | 1997-11-05 |
| GB2204067B (en) | 1991-11-27 |
| BR8801679A (en) | 1988-11-16 |
| DE3712339A1 (en) | 1988-10-20 |
| CA1332910C (en) | 1994-11-08 |
| GB2204067A (en) | 1988-11-02 |
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