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
  • C23C22/18—Orthophosphates containing manganese cations
  • C23C22/186—Orthophosphates containing manganese cations containing also copper 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
• • 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
• • 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
  • C23C22/184—Orthophosphates containing manganese cations containing also zinc cations containing also nickel cations

Definitions

• the invention relates to an aqueous, phosphate-containing solution for the production of phosphate layers on metallic Surfaces made of iron, steel, zinc, zinc alloys, aluminum or aluminum alloys.
• the invention further relates to a Process for phosphating using an aqueous Phosphating solution.
• DE-PS750957 discloses a method for improving the corrosion resistance of metals, in particular iron and steel, by treatment in a solution which forms phosphate coatings, in which the solution contains an accelerating agent and in which nitromethane, nitrobenzene, picric acid are used as accelerating agents , a nitraniline, a nitrophenol, a nitrobenzoic acid, a nitroresorcinol, nitrourea, a nitrourethane or nitroguanidine is used.
• the optimum concentration for the individual accelerators is different, but it is generally between 0.01 and 0.4% by weight in the phosphating solutions.
• the optimal concentration for the accelerator nitroguanidine should be 0.2% by weight.
• DE-PS750957 makes no information about the zinc content, the S value and the Zn-P 2 O 5 ratio of the phosphating solution.
• DE-PS 977633 assumes that a phosphating bath cannot be operated solely with organic accelerators, since the iron accumulates more and more during the phosphating process in the bath, as a result of which the bath quickly becomes unusable and the phosphate layer becomes increasingly coarse-grained with increasing service life and thus gets worse in quality.
• this document proposes a process for the production of phosphate coatings on ferrous metal objects in dilute, phosphoric acid solutions of the primary phosphates of zinc, manganese, cadmium, calcium and magnesium, in which the phosphating bath from time to time or continuously one or more organic accelerating agents, such as For example, nitroguanidine and hydrogen peroxide are added in such a way that the concentration of the organic accelerator in the bath is kept above 0.1% and at the same time a small excess of hydrogen peroxide is maintained in the bath over the amount required for the oxidation of the Fe 2+ ions.
• DE-PS 977633 therefore encourages the person skilled in the art to use nitroguanidine not only as an accelerator but always in combination with hydrogen peroxide.
• DE-OS 38 00 835 discloses a process for phosphating metal surfaces, in particular surfaces made of iron, steel, zinc and their alloys and aluminum as a pretreatment for cold forming, in which the surface is activated without activation in the temperature range from 30 to 70 ° C in contact with an aqueous solution containing 10 to 40 g Ca 2+ / l, 20 to 40 g Zn 2+ / l, 10 to 100 g PO 4 3- / l and as an accelerator 10 to 100 g NO 3 - / l and / or 0.1 to 2.0 g of organic nitro compounds per liter, the solution having a pH in the range from 2.0 to 3.8 and a ratio of free acid to total acid of 1: 4 to 1: 100.
• An m-nitrobenzenesulfonate and / or nitroguanidine can be used as accelerator.
• the phosphate layers produced by the known method have layer weights of 3 to 9 g / m 2 .
• the invention is therefore based on the object of an aqueous Solution for phosphating metallic surfaces too create that contains nitroguanidine as an accelerator and the remaining components are coordinated so that the phosphate layers formed during the phosphating are fine crystalline, have a low layer weight, enable good paint adhesion and good Ensure protection against corrosion. Furthermore, the invention is the Task based on a process for phosphating create the phosphating solution according to the invention used, the method at the lowest possible Temperatures should work for phosphating different metallic surfaces can be used can and using simple technical means as well must work reliably.
• the phosphating solution according to the invention can be used to produce very fine-crystalline phosphate layers which provide excellent paint adhesion and good corrosion protection.
• the crystallites have a plate-like, cuboid or cube-like shape and always have a maximum edge length of ⁇ 15 ⁇ m, which is usually even ⁇ 10 ⁇ m.
• the phosphating solution according to the invention is very suitable for phosphating cavities.
• the phosphate layers deposited on the metallic objects from the phosphating solution according to the invention have a layer weight of 1.5 to 4.5 g / m 2 , preferably of 1.5 to 3 g / m 2 , whereby the paint adhesion is favored in an advantageous manner. With a zinc content> 5 g / l, the corrosion protection properties and paint adhesion deteriorate significantly.
• the Zn: P 2 O 5 ratio relates to the total P 2 O 5.
• the determination of the total P 2 O 5 is based on the titration of the phosphoric acid and / or the primary phosphates from the equivalence point of the primary phosphate to the equivalence point of the secondary phosphate.
• the S value indicates the ratio of free acid, calculated as free P 2 O 5 , to total P 2 O 5 .
• the definitions and determination methods for total P 2 O 5 and free P 2 O 5 are explained in detail in the publication by W. Rausch "Die Phosphatmaschine von Metallen", 1988, pages 299 to 304.
• this solution according to the invention which is suitable for carrying out the low zinc phosphating because of its zinc content of 0.3 to 3 g / l, particularly good work results have been achieved overall.
• the aqueous solution contains 0.5 to 20 g NO 3 - / l.
• the nitrate content according to the invention advantageously favors maintaining the optimal layer weight of 1.5 to 4.5 g / m 2 .
• the nitrate is the phosphating solution in the form of alkali metal nitrates and / or by the cations present in the system, for. B. as zinc nitrate, and / or as HNO 3 added. Since the nitrate-free aqueous solution also delivers good phosphating results, the known acceleration effect of the nitrate is in most cases of minor importance in the present case.
• the phosphating solution 0.01 to 3 g Mn 2+ / l and / or 0.01 to 3 g Ni 2+ / l and / or 1 to 100 mg Cu 2+ / l and / or Contains 10 to 300 mg Co 2+ / l.
• These metal ions are built into the phosphate layer and improve paint adhesion and corrosion protection.
• the aqueous phosphating solution 0.01 to 3 g F - / l and / or 0.05 to 3.5 g / l complex fluoride, preferably (SiF 6 ) 2- or (BF 4 ) - contains.
• the fluoride is added to the phosphating solution when metallic surfaces consisting of aluminum or aluminum alloys are to be phosphated.
• the complex fluorides are added to the phosphating solution, in particular for stabilization, whereby a longer service life of the phosphating baths is achieved.
• the object underlying the invention is further achieved by the creation of a process for phosphating solved at who cleaned the metallic surfaces, then with the aqueous, phosphate-containing phosphating solution during a time of 5 seconds to 10 minutes at one temperature treated from 15 to 70 ° C and finally rinsed with water become.
• This procedure can be done with simple technical Funds are carried out and works extraordinarily reliable.
• the generated with the process Phosphate layers have a consistently good quality that even with a longer operating time of the phosphating bath does not decrease.
• the minimum phosphating time is at Process according to the invention less than in known Low zinc process with the usual accelerators work.
• the minimum phosphating time is the time in which the surface is 100% covered with a phosphate layer.
• the treatment of the metallic surfaces with the phosphating solution is carried out by spraying, dipping, splash-dipping or rolling.
• These working techniques open up a very broad and diverse range of applications for the method according to the invention.
• the metallic surfaces after cleaning with a Activating agents are treated, which is a titanium-containing Contains phosphate. This will form a closed, fine crystalline zinc phosphate layer supported.
• the metallic surfaces after the one following the phosphating After-rinsing process treated with a passivating agent become.
• the passivating agents used can both Be Cr-containing as well as Cr-free.
• Cleaning the metallic surfaces will be both mechanical impurities as well as adhering fats from the surface to be phosphated removed.
• the cleaning of the metallic surfaces belongs to the known state of the art Technique and can be advantageous with an aqueous alkaline Cleaners are carried out. It is useful if the metallic surfaces rinsed with water after cleaning become. Rinsing the cleaned or the phosphated metallic surfaces are done either with tap water or with deionized water.
• the phosphating solution according to the invention is thereby prepared that about 30 to 90 g of a concentrate, which the inorganic components of the phosphating solution and Contains water, be made up to 1 liter with water. Then the intended amount of nitroguanidine in Form a suspension or as a powder in the Phosphating solution introduced. The solution is then ready to use and during phosphating consumed substances can be added continuously by adding the Concentrate and the nitroguanidine are supplemented.
• the invention provides that the nitroguanidine is introduced into the aqueous solution in the form of a stabilized suspension.
• the suspension is stabilized with a layered silicate.
• This suspension contains 100 to 300 g nitroguanidine / l, 10 to 30 g layered silicate / l and the rest water. It can be easily pumped and is stable over 12 months, which means that the nitroguanidine does not settle even after a long time.
• the suspension is prepared by suspending the layered silicate in 1 liter of completely deionized water and then stirring in the nitroguanidine.
• layered silicates [Mg 6 (Si 7.4 Al 0.6) O 20 (OH) 4] Na 0.6 x xH 2 O and [(Mg 5.4 Li 0.6) Si 8 O 20 (OH 3 F) 4] Na 0.6 x xH 2 O especially proven.
• These are synthetically produced three-layer silicates of the smectite type.
• the layered silicates have no adverse effect on the formation of the phosphate layers. In addition to their actual beneficial effect, they also improve the sedimentation of the phosphate sludge and increase its solids content.
• Embodiments 3 and 4 were applied carried out the following process conditions, wherein in particular the suitability of the invention for phosphating Cavities should be checked: steel sheets were in one Box that simulated a cavity corresponding to the Process steps a) to e) treated, which also in the Embodiments 1 and 2 were used. The The phosphated steel sheets were dried in the cavity (Box) at room temperature without compressed air. The composition the aqueous used to phosphate a cavity Solutions and the properties of the phosphate layers result from Table 3.
• the phosphate layers of working examples 3 and 4 had regarding layer weight, crystallite edge length and Minimum phosphating time about the same properties as that Phosphate layers of working examples 1 and 2.
• the Comparative experiments D and E were carried out, the individual Process steps were identical.
• the two Comparative experiments D and E used phosphating solutions are known per se and contain accelerators Hydroxylamine.
• the composition of the to carry out the Comparative experiments D and E used solutions and the Properties of the phosphate layers are in Table 4 specified.
• a comparison of the embodiments 3 and 4 with the Comparative experiments D and E show that with the invention very good phosphating of cavities can be achieved because according to the invention complete, creates closed phosphate layers, and a Flash rust does not occur.
• the term "rust formation” implies that on the metallic surface, the does not have a complete, closed phosphate layer, forms a rust layer during drying, which is very is disadvantageous. In some cases, rust formation remains from, although not a complete, closed phosphate layer what is present on a passivation of the metallic Surface due to the phosphating solution is likely to be based.
• Paint adhesion test values determined.
• Table 5 shows the paint adhesion and corrosion protection test values for different sheets (Substrates) were determined, the individual substrates according to Examples 5,6 and 7 with inventive Solutions and according to the comparative experiments F and G with known solutions have been phosphated by immersion. The The individual substrates were dipped in accordance with the Process steps a) to f) mentioned above. The Composition of the used for Examples 5, 6 and 7 Phosphating solutions are given in Table 7. There there are also the compositions of the known Phosphating solutions used to run the Comparative experiments F and G have been used. After An electrodeposition paint was used to phosphate the substrates by dipping, a filler and a top coat.
• the composition of the aqueous Phosphating solutions required to carry out Examples 8, 9 and 10 were used are shown in Table 8.
• the Composition of the known phosphating solution for Execution of the comparative test H was used also in Table 8.
• On by spraying phosphated substrates was then a Electrocoat, a filler and a topcoat applied.
• the phosphated and painted substrates then became one Testing by outdoor exposure for 6 months a salt spray test, through a cross cut and through a 12-round climate change test with subsequent Subject to falling rocks.
• Table 6 are those for test values determined for individual substrates, where for the cross cut a rating grade and for the Outdoor weathering, the salt spray test and the climate change test measured the infiltration of the paint layer in mm. For the falling rocks the Paint flaking mentioned in percent.
• the corrosion protection achieved by the phosphating according to the invention is comparable to the corrosion protection which occurs through the use of proven, known phosphating processes which work with the nitrite accelerator.
• the phosphating according to the invention avoids the use of the accelerator nitrite, the use of which is increasingly being rejected, since nitrite produces reaction products during the phosphating which damage the environment and are sometimes toxic to humans.
• the paint adhesion and corrosion protection effect achieved by the phosphating according to the invention can be rated as very good to good.

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• 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)
• Physical Or Chemical Processes And Apparatus (AREA)

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• 1996
  • 1996-08-28 DE DE19634685A patent/DE19634685A1/de not_active Withdrawn
• 1997
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  • 1997-08-11 SI SI9730079T patent/SI0922123T1/xx unknown
  • 1997-08-11 HU HU9903091A patent/HU228330B1/hu unknown
  • 1997-08-11 BR BR9713177-6A patent/BR9713177A/pt not_active IP Right Cessation
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  • 1997-08-11 CN CN97198243A patent/CN1080325C/zh not_active Expired - Lifetime
  • 1997-08-11 WO PCT/EP1997/004360 patent/WO1998008999A1/de active IP Right Grant
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  • 1997-08-11 DK DK97943803T patent/DK0922123T3/da active
  • 1997-08-11 AT AT97943803T patent/ATE195005T1/de active
  • 1997-08-11 KR KR10-1999-7001494A patent/KR100473779B1/ko not_active IP Right Cessation
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• 2000
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