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
  • C23C22/07—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
• • 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
  • C23C22/364—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 manganese cations
  • C23C22/365—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 manganese cations containing also zinc and nickel 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
  • C23C22/78—Pretreatment of the material to be coated
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12736—Al-base component
  • Y10T428/1275—Next to Group VIII or IB metal-base component
  • Y10T428/12757—Fe

Definitions

• the present invention relates to an aqueous composition and a process for the corrosion-protective conversion treatment of metallic surfaces.
• the aqueous composition is particularly suitable for treating various metallic materials joined together in composite structures, including steel or galvanized or alloy galvanized steel, and any combination of these materials, which composite structure is at least partially composed of aluminum or its alloys.
• alloys are always included that consist of more than 50 atomic% of aluminum.
• the metallic surfaces of the composite structure treated according to the invention can be coated homogeneously and with outstanding adhesion properties in a subsequent dip coating, so that post-passivation of the conversion-treated metallic surfaces can be dispensed with.
• the clear advantage of the aqueous composition according to the invention for the treatment of metallic surfaces consists in the selective coating of different metal surfaces with a crystalline phosphate layer in the case of steel or galvanized or alloy galvanized steel surfaces and a non-crystalline conversion layer on the aluminum surfaces such that an excellent passivation of the metallic surfaces and a sufficient paint adhesion for subsequently applied paint results.
• the application of the aqueous composition according to the invention therefore enables a one-step process for the anticorrosive pretreatment of composite metal structures.
• the accumulation of aluminum ions in the bath solution leads to a significant deterioration of the phosphating process, in particular the quality of the conversion layer.
• the formation of a homogeneous crystalline phosphate layer on steel surfaces does not occur in the presence of trivalent cations of aluminum.
• Aluminum ions therefore act as a poisonous agent in phosphating and must be effectively masked by suitable additives in the case of standard treatment of bodies which have partially aluminum surfaces.
• a suitable masking of the aluminum ions may be via the addition of fluoride ions or fluoro complexes such as SiF 6 2- , as in US 5,683,357 disclosed to be achieved.
• hexafluoroaluminates for example in the form of cryolite, can be precipitated from the bath solution, which contribute to a considerable extent to the formation of sludge in the phosphating bath and thus considerably complicate the processability of the phosphating.
• the formation of a phosphate layer on the aluminum surface takes place only at high pickling rates, ie a relatively high concentration of free fluoride ions.
• the control of defined bath parameters, in particular the free fluoride content is of considerable importance for a sufficient corrosion protection and a good paint adhesion. Insufficient phosphating of the aluminum surfaces always requires post-passivation in a subsequent process step.
• optical defects after the coating primer caused by an inhomogeneously deposited phosphate layer are basically not curable.
• DE10322446 uses conventional phosphating and adds water-soluble zirconium and / or titanium compounds, with a certain amount, but not more than 5000 ppm, of free fluoride.
• phosphating solutions in which the total content of zirconium and / or titanium is in a range from 10 to 1000 ppm, preferably 50 to 250 ppm, can be dispensed with after passivation of both the phosphated metal surfaces and the aluminum surfaces.
• the single-stage process of a conversion treatment of metallic surfaces which at least partially comprise aluminum surfaces is carried out with constantly high fluoride contents, which causes a high pickling rate and thus a massive introduction of aluminum ions into the bath solution. It is the associated technical effort in bath control and treatment, which inevitably results from increased sludge formation in the phosphating. Furthermore, sedimented aluminate particles can remain on the components which have undergone such a conversion, which after the deposition of the coating primer cause a negative visual impression of the painted components or impair the paint adhesion and mechanical resistance of the paint.
• the DE10231279 relates to a process for the corrosion-protective pretreatment of metal surfaces, which consist of at least 5% of aluminum surfaces and in addition to these aluminum surfaces predominantly surfaces of iron and / or zinc.
• the DE10231279 teaches therefore a method for corrosion-protective treatment of metals in mixed construction. According to the process described there, crystalline coatings are to be produced on all metal surfaces.
• the corrosion protection pretreatment after the DE10231279 is made by means of a composition suitable for zinc phosphating, said composition having in addition to 0.2-4 g / l of zinc ions and 4-65 g / l of phosphate ions a free fluoride content in the range of about 30-500 ppm , preferably in the range of 85-350 ppm.
• the DE10231279 discloses that the composition contains an additional amount of dissolved titanium or zirconium in the Range of 1-200 ppm, wherein the proportion of these elements in the composition is preferably zero.
• the WO 02/070782 A2 relates to a method for nickel-free phosphating of metal surfaces by contacting with phosphating, which can contain in addition to zinc and phosphate ions also a proportion of free fluoride and complex fluorides based on the elements zirconium and / or titanium.
• the proportion of free fluoride in the phosphating solution is preferably in the range of about 1-800 ppm.
• the proportion of complex fluorides of zirconium and / or titanium in the phosphating solution is preferably in the range of about 3-300 ppm based on F6.
• the WO 02/070782 A2 further teaches that for the treatment of aluminum surfaces, a value of about 50 ppm relative to F6 should not be exceeded. That in the WO 02/070782 A2
• the process disclosed is particularly suitable for zinc surfaces, but can also be used for metal surfaces consisting of at least one of the materials based on aluminum, iron, steel and zinc.
• F / mM and Me / mM represent the free fluoride (F) or reduced zirconium and / or titanium concentration (Me) reduced by the unit of concentration in mM (10 -3 mol / L).
• the quotient ⁇ is at least 4.
• Ratio ⁇ for aqueous compositions which according to the invention contain both components (c), ie zirconium and titanium compounds, is the Ratio ⁇ according to formula (I) should not be less than Zr / mM Zr / mM + Ti / mM ⁇ 4 + Ti / mM Zr / mM + Ti / mM ⁇ 6
• the proportion of free fluoride in such an aqueous composition is determined potentiometrically with the aid of a fluoride-sensitive glass electrode.
• a detailed description of the measuring method, the calibration and the experimental procedure for determining the free fluoride concentration can be found in the description of the embodiments of the present invention.
• zirconium compounds provides technically better results than the use of titanium compounds in the different embodiments of the present invention.
• complex fluoro acids or their salts can be used.
• the aqueous composition in the process according to the invention for corrosion-protective conversion treatment can be used in addition to 0.3 to 3 g / l Zn (II) and 5 to 40 g / l Phosphate ions as well 1 to 200 ppm one or more water-soluble compounds of zirconium and / or titanium based on the element zirconium and / or titanium also contain at least one of the following accelerators: 0.3 to 4 g / l chlorate, 0.01 to 0.2 g / l Nitrite ions, 0.05 to 4 g / l nitroguanidine, 0.05 to 4 g / l N-methyl-N-oxide, 0.2 to 2 g / l m-nitrobenzenesulfonate ions, 0.05 to 2 g / l m-nitrobenzoate ions, 0.05 to 2 g / l p-nitrophenol, 1 to 150 mg / l Hydrogen peroxide in free or bound form,
• Such accelerators are known in the art as components of Phosphatierbädem and fulfill the role of "hydrogen scavengers" by these by the Acid attack on the metallic surface resulting hydrogen directly oxidize and thereby be reduced.
• the formation of a homogeneous crystalline zinc phosphate layer is greatly facilitated by the accelerator, which reduces the formation of gaseous hydrogen on the metal surface.
• Corrosion protection and lacquer adhesion of the crystalline zinc phosphate layers produced with an aqueous composition in the process according to the invention are, according to experience, improved if one or more of the following cations is additionally present: 0.001 to 4 g / l Manganese (II), 0.001 to 4 g / l Nickel (II), 0.001 to 4 g / l Cobalt (II) 0.002 to 0.2 g / l Copper (II), 0.2 to 2.5 g / l Magnesium (II) 0.2 to 2.5 g / l Calcium (II), 0.01 to 0.5 g / l Iron (II), 0.2 to 1.5 g / l Lithium (I), 0.02 to 0.8 g / l Tungsten (VI).
• the zinc concentration is preferably in the range between about 0.3 and about 2 g / l, and more preferably between about 0.8 and about 1.4 g / l.
• Higher levels of zinc do not provide significant benefits to the conversion treatment of the invention with the aqueous composition, but on the other hand cause increased sludge build up in the treatment bath.
• high levels of zinc can occur in a working treatment bath when mainly galvanized surfaces are phosphated and thus additional zinc is introduced into the treatment bath as a result of the pickling process.
• Aqueous conversion conversion compositions containing both manganese and nickel ions in addition to zinc ions are well known to those skilled in phosphating as trication-phosphating solutions and are also useful in the present invention suitable.
• usual share of up to 3 g / l nitrate facilitates the formation of a crystalline homogeneous and closed phosphate layer on the steel, galvanized and alloy-galvanized steel surfaces.
• hexafluorosilicate anions can be added to the aqueous composition for the anticorrosive conversion treatment according to the invention, since these are capable of complexing the trivalent aluminum cations introduced into the bath solution, so that the phosphating is optimized and the so-called "speck formation” occurs under the formation of specks on the surface increased pickling rate associated with the deposition of amorphous, white zinc phosphate, is prevented on galvanized substrates.
• the aqueous treatment solution preferably has a free acid content, each staggered in accordance with an increasing preference, of at least 0; 0.2; 0.5; 0.8; 1 point but not more than 3; 2.5; 2; 1.5 points.
• a total acid content of the treatment solution each staggered according to an increasing preference, of at least 20; 21; 22 points but not more than 26; 25; 24 points available.
• the term free acid is well known to those skilled in the phosphating art.
• the method of determination specific for this invention for determining the free acid or the total acid content is given in the examples section.
• the pH of the aqueous treatment solution is preferably not less than 2.2 with increasing preference. 2.4; 2.6; 2.8 but not greater than 3.6; 3.5; 3.4; 3.3; 3.2.
• aqueous composition for the conversion treatment according to the invention composed of metallic materials composite structures, which at least partially also aluminum surfaces, takes place after cleaning and degreasing of the surfaces by bringing the surfaces in contact the aqueous composition according to the invention, for example by spraying or dipping, at bath temperatures in the range of 20-65 ° C for a time interval tuned to the convection in the bath and for the composition of the composite structure to be treated.
• a dipping process is usually followed by a rinse with city water or demineralized water, after work-up of enriched with components of the treatment solution rinse water, a partial recycling of rinse water components can be made in the bath solution.
• the thus treated metallic surfaces of the composite structure can be provided with a base coat in a further step, preferably with an organic electrodeposition paint.
• a post-passivation of the phosphated and / or passivated metal surfaces with an aqueous composition can take place, which is at least 200 contains up to 1500 ppm of fluorocomplexes of zirconium and / or titanium based on the elements zirconium and / or titanium and optionally 10 to 100 ppm of copper (II) ions.
• the pH of such a post-passivation solution is in the range of 3.5 to 5.5.
• a composite structure treated in accordance with the method according to the invention composed inter alia of steel and / or galvanized and / or alloy-galvanized steel components and aluminum components, has coating weights of phosphating of 0.5 to 4.5 g on its metallic surfaces on which a crystalline zinc phosphate layer has been formed / m 2 on.
• the metallic surfaces which can be treated with the aqueous composition according to the method for forming a conversion layer are preferably steel, galvanized steel and alloy galvanized steel, and aluminum and alloys of aluminum having an alloying content of less than 50 at% Alloy components silicon, magnesium, copper, manganese, Zinc, chromium, titanium and nickel come into question.
• the metallic surface may be composed of any combination of said materials in a composite structure.
• the converted in accordance with the underlying invention metallic materials, components and composite structures are used in automotive production in the body shop, shipbuilding, construction and for the production of white goods use.
• Table 1 shows the sequence of processes for the inventive treatment of the sample sheets, as is in principle also customary in automotive bodywork.
• the sheets are alkaline cleaned and degreased and prepared after a rinsing with a titanium phosphate-containing activating solution for the conversion treatment according to the invention.
• commercially available products by the applicant were used: Ridoline® ® 1569 A, Ridosol ® 1270, FIXODINE ® 50 CF.
• the free acid score is determined by diluting 10 ml bath sample to 50 ml and titrating to pH 3.6 with 0.1 N sodium hydroxide solution. The consumption of ml of sodium hydroxide gives the score. Accordingly, the content of total acid is determined by titrating to a pH of 8.5.
• the content of free fluoride in the aqueous composition for the conversion treatment is detected by means of a potentiometric measuring chain (inoLab pH / Ion Level 3, from WTW).
• the measuring chain contains a fluoride-sensitive glass electrode (F501, Fa. WTW) and a reference electrode (R503, Fa. WTW).
• F501, Fa. WTW fluoride-sensitive glass electrode
• R503, Fa. WTW reference electrode
• For two-point calibration of both electrodes are immersed together in sequence in the calibration solutions with a content of 100 ppm and 1000 ppm prepared from the Titrisol ® fluoride standard of Fa. Merck without buffer addition.
• the resulting measured values are correlated with the respective fluoride content "100" or "1000" and read into the measuring instrument.
• the steepness of the glass electrode is then displayed in mV per decade of the fluoride ion content in ppm on the meter, typically between -55 and -60 mV.
• the fluoride content in ppm can then be determined directly by immersing the two electrodes in the cooled bath solution for conversion treatment.
• Table 1 Process for Conversion Treatment of Aluminum (AC 120), CRS ST1405 (Sidca) and HDG (Thyssen) steps 1. alkaline cleaning 2nd flushing process 3. Activate 4. phosphating 5. rinsing process 6.
• Table 2 shows the pickling rates for the substrate aluminum as a function of the concentration of free fluoride and zirconium for a process sequence according to Table 1. As expected, the pickling rate increases with each increase in fluoride concentration. Surprisingly, the pickling rate on aluminum is significantly reduced by the addition of 50 ppm, and in the case of a free fluoride concentration of 30 and 55 ppm, the pickling rate is reduced by 50% compared with an aqueous composition for conversion treatment containing no zirconium.
• Tables 8 to 10 contain, depending on the quotient ⁇ of the respectively used treatment solutions a) to c) an optical assessment of phosphating on cold-rolled steel, since the formation of a closed and homogeneous zinc phosphate layer is critical especially on this substrate.
• the sample sheet is subdivided into a line grid in such a way that an optical individual evaluation of approximately 1 cm 2 square fields is made.
• the mean value of the covering degrees summed over all individual fields then yields, semi-quantitatively, the total coverage of the respective sheet with the phosphate layer as a percentage of the sheet metal surface examined, whereby this consists of at least 64 individual fields. Coated and uncoated areas are distinguishable for the skilled person due to their different reflectivity and / or color.

Priority Applications (2)

Applications Claiming Priority (2)

Publications (2)

Family

ID=38704784

Family Applications (1)

Country Status (14)

Cited By (1)

Families Citing this family (19)

Family Cites Families (17)

• 2006
  • 2006-11-08 DE DE102006052919A patent/DE102006052919A1/de not_active Withdrawn
• 2007
  • 2007-09-13 JP JP2009535644A patent/JP5406723B2/ja active Active
  • 2007-09-13 EP EP07820181A patent/EP2092090B1/de active Active
  • 2007-09-13 RU RU2009121446/02A patent/RU2464356C2/ru not_active IP Right Cessation
  • 2007-09-13 ES ES07820181T patent/ES2398594T3/es active Active
  • 2007-09-13 CN CN2007800414397A patent/CN101535528B/zh active Active
  • 2007-09-13 CA CA2669042A patent/CA2669042C/en active Active
  • 2007-09-13 SI SI200731183T patent/SI2092090T1/sl unknown
  • 2007-09-13 KR KR1020097009359A patent/KR20090086405A/ko active Search and Examination
  • 2007-09-13 WO PCT/EP2007/059628 patent/WO2008055726A1/de active Application Filing
  • 2007-09-13 BR BRPI0718578-2A patent/BRPI0718578A2/pt not_active Application Discontinuation
  • 2007-09-13 PL PL07820181T patent/PL2092090T3/pl unknown
• 2009
  • 2009-04-22 US US12/427,785 patent/US8801871B2/en active Active
  • 2009-05-07 ZA ZA200903169A patent/ZA200903169B/xx unknown
• 2012
  • 2012-03-19 US US13/423,558 patent/US8956468B2/en active Active

Also Published As

Similar Documents

Legal Events