CA1333147C - Process of phosphating steel and/or galvanized steel before painting - Google Patents
Process of phosphating steel and/or galvanized steel before paintingInfo
- Publication number
- CA1333147C CA1333147C CA000574254A CA574254A CA1333147C CA 1333147 C CA1333147 C CA 1333147C CA 000574254 A CA000574254 A CA 000574254A CA 574254 A CA574254 A CA 574254A CA 1333147 C CA1333147 C CA 1333147C
- Authority
- CA
- Canada
- Prior art keywords
- phosphating
- contain
- galvanized steel
- spraying
- dipping
- 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 - Fee Related
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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
- C23C22/368—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 magnesium cations
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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)
Abstract
In a process of phosphating metal surfaces of galvanized steel or of galvanized steel and aluminum, before a painting, the metallic surfaces are treated at a temperature between 40 and 60°C with an aqueous phosphating solutions which contain 0.4 to 5.0 g/l Mg, 0.05 to 2.0 g/l Ni, 8 to 20 g/l P2O5 and at least one oxidizing agent and wherein the ratio of free acid to total acid is (0.02 to 0.15) : 1. Where aluminum is absent the metallic surfaces are treated with phosphating solutions which when used in a spraying process are adjusted to contain between 0.4 and 1.0 g/l zinc and when used in a spraying-dipping process and in a dipping process are adjusted to contain between 0.9 and 1.5 g/l zinc. In the presence of aluminum the metallic surfaces are treated with phosphating solutions which for use in a spraying process are adjusted to contain between more than 0.8 and 1.0 g/l zinc and for use in a spraying-dipping process or in a dipping process are adjusted to contain between 1.4 and 2.0 g/l zinc and further are adjusted to contain 80 to 400 mg/l fluoride (F(el) as determined with a fluoride-sensitive electrode immersed into the bath solution.
Description
1 3331 ~7 The present invention relates to a process of phos-phating metal surfaces of galvanized steel or of galvanized steel and aluminum, before the metal is painted, wherein ~ ing solutions based on zinc-magnesium phosphate are employed.
It is known to treat metals with a solution of zinc-magnesium phosphate in order to deposit phosphate layers on the metals. It is also known in the art to perform low-zinc phosphating processes particularly before a painting step because the phosphate layers thus formed on steel have a high content of phosphophyllite, which has a favorable influence on the adhesion of the pain and the resistance of the paint film against creepback due to corrosive attack.
But the known processes have various disadvantages. For instance, only an inadequate layer is often formed on zinc in phosphating baths which contain only Zn and Mg as cations. Whereas the use of nickel-containing low-zinc phosphating baths will result in a formation of visually satisfactory phosphate layers on steel and zinc, the adhesion of paint films on zinc under the action of moisture is often inadequate. Particularly when formed in a dipping process, phosphate layers often exhibit surface irregularities which are described as stipples and are due to local crystalline efflorescence and will disturb the formation of a uniform paint film. Besides, difficulties will arise in the formation of crystalline phosphate layers on aluminum from baths which are based on zinc-magnesium phosphate.
It is an object of the invention to prDvide for the phos-phating of metal surfaces of galvanized steel, or of hetero-geneous s~Ld~ of galvanized steel and ~ , in ~L~ ~ ~Lion for p~nting, a ~ess which is fiw of the dis~v~lLay~s mentioneA here-ill~ero.~ and which permits a format~on on the metals of phosphate ~r layers which are uniform and provide an excellent base for painting.
That object is accomplished in that the process described first hereinbefore is carried out in such a manner in accordance with the invention that the metal surfaces are contacted at a temperature between 40 and 60C with aqueous phosphating solutions which contain 0.4 to 5.0 g/l Mg 0.05 to 2.0 g/l Ni 8 to 20 g/l P205 and at least one oxidizing agent and wherein the ratio of free acid to total acid is (0.02 to 0.15) : 1, provided that a) when the metal surface to be phosphated is a metal surface of galvanized steel, the zinc concentration of the phosphating solution is adjusted to a value in the range of 0.4 to 1.0 g/l when applied in a spraying process, and to a value in the range of 0.9 to 1.5 g/l when applied in a spraying-dipping or dipping process; and b) when the metal surface to be phosphated is a heterogeneous metal surface of galvanized steel and aluminum, the zinc concentration of the phosphating solution is adjusted to a value varying between more than 0.8 to l.o g/l when ~5 applied in a spraying process, and to a value in the range of 1.4 to 2.0 g/l when applied in a spraying-dipping or dipping process, and the phosphating solutions contain additionally 80 to 400 mg/l fluoride "F(el)" as determined with a fluoride-sensitive electrode which is immersed into the bath solution.
Within the scope of the invention the term galvanized steel describes a steel which has been provided with a coating of zinc or a zinc alloy, such as pure zinc, zinc-nickel, zinc-iron, zinc-aluminum in a suitable process, such as melt dipping or electrodeposition. Within the scope of the invention, the term aluminum describes, inter alia, pure aluminum and alloys of aluminum with magnesium, zinc, ,--copper, silicon, manganese, etc.
The feature which resides in that solutions for use in the presence also of aluminum contain between 80 and 400 mg/l fluoride means that where aluminum is present such a f~ content is essential for a formation of a crystalline layer on aluminum. The feature does not mean that the solutions may not contain fluoride also where no aluminum is present.
The fluoride content which is measured with a fluoride-sensitive electrode corresponds approximately to the content of dissociated fluoride (F ) in the phosphating solution. For an adjustment of an F(el) content between 80 and 400 mg/l in phosphating baths having a conventional pH
value, about 0.4 to 0.9 g/l NH4HF2 or an equivalent quantity of other compounds which contain simple fluorides must be added. The replenishment of the bath is preferably effected in that the compound which contains simple fluoride is added to the phosphating bath in the quantity which is required to obtain the desired measured value of F(el).
The metallic surfaces to be treated must be free of disturbing covering of oils, lubricants, oxides and the like, which might adversely affect the formation of a satisfactory layer. To that end the surfaces are cleaned in a suitable manner. The formation of the phosphate layer may preferably be assisted in that surface is activated with an activating agent known per se, such as an aqueous suspension of titanium phosphate, before the phosphate coating is formed. The activating agent may be used in the cleaning bath or in a separate process stage.
The phosphating solutions in accordance with the invention are used by spraying, spraying-dipping or dipping at temperatures between 40 and 60 C. The times for which the metallic surfaces are contacted with the phosphating solution in order to form a covering uniform phosphate layer 13-~3147 are e.g., between 20 seconds and 10 minutes in the treatment of galvanized steel and, e.g., between 1 minute and 10 minutes in the treatment of aluminum. By the expression spraying-dipping we should understand spraying and dipping.
The cations zinc, magnesium and nickel are introduced into the phosphating solution, e.g., as metal, oxide, carbonate, phosphate, nitrate, chloride and/or complex fluoride. Phosphate is added to the solution in the form of phosphate and/or phosphoric acid. Additional cations, such as Na, K, NH4, or anions such as nitrate, chloride, sulfate, are used to adjust a ratio of (0.02 to 0.15) : 1 of free acid to total acid.
The content of free acid (total acid) equals the consumption of 0.lN NaOH in ml which is required to neutralize a 10 ml bath sample against the first (second) point of inflection of phosphoric acid.
The phosphating bath preferably contains also at least one oxidizing agent of the group consisting of nitrate, nitrite, chlorate, bromate, peroxide and nitrobenzene sulfonate, which may be used, e.g., in the following quantities: 2 to 20 g/l nitrate; 0.05 to 0.5 g/l nitrite; 0.5 to 5 g/l chlorate; 0.2 to 3 g/l bromate; 0.02 to 0.1 g/l peroxide; 0.1 to 1 g/l nitrobenzene su,lfonate.
The oxidizing agents may be combined with each other, such as nitrate-nitrite, chlorate-nitrite, nitrate-chlorate-nitrite, nitrate-bromate, chlorate-nitrobenzene sulfonate, nitrate-chlorate-nitrobenzene sulfonate, nitrate-nitrobenzene sulfonate.
In order to avoid in the phosphating of galvanized steel the formation of small dotlike crystalline efflorescences (stipples) on the phosphate layer, particularly where the spraying-dipping and dipping processes are used, a special feature of the invention resides in that only two of the three components consisting B
- 4a - 1 333 1 47 of (chloride and/or bromide), nitrate and nickel may be present in a concentration in excess of o.l g/l each whereas /
/
.. . .
~' the content of the third component must not exceed 0.1 g/l.
In that connection chloride and bromide are regarded as one component and their individual concentrations are added to each other. Chloride may enter the phosphating bath, e.g, from the water used to prepare the phosphating solution and/or as a reduction product of chlorate. A bromide source may particularly be consituted by the bromate accelerator.
In order to assist the formation of the layer on aluminum-containing zinc coatings, the phosphating bath preferably contains simple and/or complex fluoride. The group of complex fluorides which are suitable includes, e.g., fluoroborates and fluorosilicates.
In addition to the components which have been described, the phosphating solutions used in the process in accordance with the invention may contain further additives, which in most cases are present only in minor quantities.
These additives include, inter alia, copper, manganese, calcium, iron, cobalt, polyphosphates, polyhydroxycarboxylic acids, surfactants and agents for controlling the settling of sludge.
The phosphate layers are formed in accordance - with the invention in preparation for a succeeding painting treatment. They are preferably formed on workpieces which are subsequently electro-dipcoated and particularly cathodically electrodipcoated. The resulting paint coatings distinguish by a high resistance against creepback due to corrosive attack, e.g., in a normal outdoor environment, or in a salt-accelerated outdoor environment or under the action of moisture or of salt-containing mists and suds, and.
by a very good adhesion under scratching and impact stresses and after corrosive action.
The process in accordance with the invention will 1333~47 be explained by way of example and more in detail with reference to the following Examples.
Examples Sheets made of electrogalvanized steel, hot-galvanized steel and AlMgSi were cleaned with an alkaline solution, rinsed with water, activated in an aqueous suspension of titanium phosphate and subsequently treated with the phosphating solutions stated in the Table at 50C for Z minutes in a spraying process or for 3 minutes in a dipping process. This was succeeded by a rinsing with water, with a chromium (VI)-containing aqueous passivating solution and with de-ionized water and by a drying stage.
It is apparent from the Table that satisfactory layers on galvanized steel were obtained throughout the range of processing conditions with exception of those cases in which the concentration of nitrate, chloride and nickel exceeded 0.1 g/l each (Examples 6 and 11) whereas the contents of Zn, Mg and Ni were within the ranges pre-scribed in accordance with the invention. A crystalline uniform layer was formed on AlMgSi whenever the concentra-tion of fluoride E(el) which had been electrometrically measured with a fluoride-sensitive electrode was between 80 and 400 mg/l (Examples 4 to 6 and 13 to 20).
After a visual inspection, the layers were covered with a paint by electro-dipcoating and with a coating structure as is used on automobiles and were subjected to the conventional tests o~ application technology. Excellent test results were obtained in all cases in which crystalline layer~ had been ~ormed on the metal substrate.
t ~
13.~3147 Table ExampleNo. 1 2 3 4 5 Zn (g/l) 0.5 0 5 0.8 more than 0.8 0.8 Mg (g/l) 1 1 1 1 2.5 Ni (g/l) 0.1 0.7 0.1 0.7 0.1 Na (g/l) 1.6 0.8 2.0 1.7 0.6 P2O5(g/1) 12 12 14 14 14 NO3 (g/l) 2 Cl (g/l) 0.1~ 0.2 C103 (g/l) 1 1.3 2 NaNo2(g/l) 0.1 0.1 0.1 Nitrobenzene i5 sulfonate (g/l) 0.3 0.3 F(el) (g/l) 0.15 0.1 SiF6 (g/l) Free acid 0.4 0.4 0.8 0.8 0.7 Total acid 17.6 18.6 21.2 22.2 21.8 ~0 free acid 0.02 0.02 0.04 0.04 0.03 total acid Application 2) Spr Spr Spr Spr Spr ~5 3) Galvanized Steel good good good good good AlMgSi 3) _ good good Explanations 1) ~ Additional enriching with Cl by a reduction of chlorate during the processing B
I
13.3314-~
It is known to treat metals with a solution of zinc-magnesium phosphate in order to deposit phosphate layers on the metals. It is also known in the art to perform low-zinc phosphating processes particularly before a painting step because the phosphate layers thus formed on steel have a high content of phosphophyllite, which has a favorable influence on the adhesion of the pain and the resistance of the paint film against creepback due to corrosive attack.
But the known processes have various disadvantages. For instance, only an inadequate layer is often formed on zinc in phosphating baths which contain only Zn and Mg as cations. Whereas the use of nickel-containing low-zinc phosphating baths will result in a formation of visually satisfactory phosphate layers on steel and zinc, the adhesion of paint films on zinc under the action of moisture is often inadequate. Particularly when formed in a dipping process, phosphate layers often exhibit surface irregularities which are described as stipples and are due to local crystalline efflorescence and will disturb the formation of a uniform paint film. Besides, difficulties will arise in the formation of crystalline phosphate layers on aluminum from baths which are based on zinc-magnesium phosphate.
It is an object of the invention to prDvide for the phos-phating of metal surfaces of galvanized steel, or of hetero-geneous s~Ld~ of galvanized steel and ~ , in ~L~ ~ ~Lion for p~nting, a ~ess which is fiw of the dis~v~lLay~s mentioneA here-ill~ero.~ and which permits a format~on on the metals of phosphate ~r layers which are uniform and provide an excellent base for painting.
That object is accomplished in that the process described first hereinbefore is carried out in such a manner in accordance with the invention that the metal surfaces are contacted at a temperature between 40 and 60C with aqueous phosphating solutions which contain 0.4 to 5.0 g/l Mg 0.05 to 2.0 g/l Ni 8 to 20 g/l P205 and at least one oxidizing agent and wherein the ratio of free acid to total acid is (0.02 to 0.15) : 1, provided that a) when the metal surface to be phosphated is a metal surface of galvanized steel, the zinc concentration of the phosphating solution is adjusted to a value in the range of 0.4 to 1.0 g/l when applied in a spraying process, and to a value in the range of 0.9 to 1.5 g/l when applied in a spraying-dipping or dipping process; and b) when the metal surface to be phosphated is a heterogeneous metal surface of galvanized steel and aluminum, the zinc concentration of the phosphating solution is adjusted to a value varying between more than 0.8 to l.o g/l when ~5 applied in a spraying process, and to a value in the range of 1.4 to 2.0 g/l when applied in a spraying-dipping or dipping process, and the phosphating solutions contain additionally 80 to 400 mg/l fluoride "F(el)" as determined with a fluoride-sensitive electrode which is immersed into the bath solution.
Within the scope of the invention the term galvanized steel describes a steel which has been provided with a coating of zinc or a zinc alloy, such as pure zinc, zinc-nickel, zinc-iron, zinc-aluminum in a suitable process, such as melt dipping or electrodeposition. Within the scope of the invention, the term aluminum describes, inter alia, pure aluminum and alloys of aluminum with magnesium, zinc, ,--copper, silicon, manganese, etc.
The feature which resides in that solutions for use in the presence also of aluminum contain between 80 and 400 mg/l fluoride means that where aluminum is present such a f~ content is essential for a formation of a crystalline layer on aluminum. The feature does not mean that the solutions may not contain fluoride also where no aluminum is present.
The fluoride content which is measured with a fluoride-sensitive electrode corresponds approximately to the content of dissociated fluoride (F ) in the phosphating solution. For an adjustment of an F(el) content between 80 and 400 mg/l in phosphating baths having a conventional pH
value, about 0.4 to 0.9 g/l NH4HF2 or an equivalent quantity of other compounds which contain simple fluorides must be added. The replenishment of the bath is preferably effected in that the compound which contains simple fluoride is added to the phosphating bath in the quantity which is required to obtain the desired measured value of F(el).
The metallic surfaces to be treated must be free of disturbing covering of oils, lubricants, oxides and the like, which might adversely affect the formation of a satisfactory layer. To that end the surfaces are cleaned in a suitable manner. The formation of the phosphate layer may preferably be assisted in that surface is activated with an activating agent known per se, such as an aqueous suspension of titanium phosphate, before the phosphate coating is formed. The activating agent may be used in the cleaning bath or in a separate process stage.
The phosphating solutions in accordance with the invention are used by spraying, spraying-dipping or dipping at temperatures between 40 and 60 C. The times for which the metallic surfaces are contacted with the phosphating solution in order to form a covering uniform phosphate layer 13-~3147 are e.g., between 20 seconds and 10 minutes in the treatment of galvanized steel and, e.g., between 1 minute and 10 minutes in the treatment of aluminum. By the expression spraying-dipping we should understand spraying and dipping.
The cations zinc, magnesium and nickel are introduced into the phosphating solution, e.g., as metal, oxide, carbonate, phosphate, nitrate, chloride and/or complex fluoride. Phosphate is added to the solution in the form of phosphate and/or phosphoric acid. Additional cations, such as Na, K, NH4, or anions such as nitrate, chloride, sulfate, are used to adjust a ratio of (0.02 to 0.15) : 1 of free acid to total acid.
The content of free acid (total acid) equals the consumption of 0.lN NaOH in ml which is required to neutralize a 10 ml bath sample against the first (second) point of inflection of phosphoric acid.
The phosphating bath preferably contains also at least one oxidizing agent of the group consisting of nitrate, nitrite, chlorate, bromate, peroxide and nitrobenzene sulfonate, which may be used, e.g., in the following quantities: 2 to 20 g/l nitrate; 0.05 to 0.5 g/l nitrite; 0.5 to 5 g/l chlorate; 0.2 to 3 g/l bromate; 0.02 to 0.1 g/l peroxide; 0.1 to 1 g/l nitrobenzene su,lfonate.
The oxidizing agents may be combined with each other, such as nitrate-nitrite, chlorate-nitrite, nitrate-chlorate-nitrite, nitrate-bromate, chlorate-nitrobenzene sulfonate, nitrate-chlorate-nitrobenzene sulfonate, nitrate-nitrobenzene sulfonate.
In order to avoid in the phosphating of galvanized steel the formation of small dotlike crystalline efflorescences (stipples) on the phosphate layer, particularly where the spraying-dipping and dipping processes are used, a special feature of the invention resides in that only two of the three components consisting B
- 4a - 1 333 1 47 of (chloride and/or bromide), nitrate and nickel may be present in a concentration in excess of o.l g/l each whereas /
/
.. . .
~' the content of the third component must not exceed 0.1 g/l.
In that connection chloride and bromide are regarded as one component and their individual concentrations are added to each other. Chloride may enter the phosphating bath, e.g, from the water used to prepare the phosphating solution and/or as a reduction product of chlorate. A bromide source may particularly be consituted by the bromate accelerator.
In order to assist the formation of the layer on aluminum-containing zinc coatings, the phosphating bath preferably contains simple and/or complex fluoride. The group of complex fluorides which are suitable includes, e.g., fluoroborates and fluorosilicates.
In addition to the components which have been described, the phosphating solutions used in the process in accordance with the invention may contain further additives, which in most cases are present only in minor quantities.
These additives include, inter alia, copper, manganese, calcium, iron, cobalt, polyphosphates, polyhydroxycarboxylic acids, surfactants and agents for controlling the settling of sludge.
The phosphate layers are formed in accordance - with the invention in preparation for a succeeding painting treatment. They are preferably formed on workpieces which are subsequently electro-dipcoated and particularly cathodically electrodipcoated. The resulting paint coatings distinguish by a high resistance against creepback due to corrosive attack, e.g., in a normal outdoor environment, or in a salt-accelerated outdoor environment or under the action of moisture or of salt-containing mists and suds, and.
by a very good adhesion under scratching and impact stresses and after corrosive action.
The process in accordance with the invention will 1333~47 be explained by way of example and more in detail with reference to the following Examples.
Examples Sheets made of electrogalvanized steel, hot-galvanized steel and AlMgSi were cleaned with an alkaline solution, rinsed with water, activated in an aqueous suspension of titanium phosphate and subsequently treated with the phosphating solutions stated in the Table at 50C for Z minutes in a spraying process or for 3 minutes in a dipping process. This was succeeded by a rinsing with water, with a chromium (VI)-containing aqueous passivating solution and with de-ionized water and by a drying stage.
It is apparent from the Table that satisfactory layers on galvanized steel were obtained throughout the range of processing conditions with exception of those cases in which the concentration of nitrate, chloride and nickel exceeded 0.1 g/l each (Examples 6 and 11) whereas the contents of Zn, Mg and Ni were within the ranges pre-scribed in accordance with the invention. A crystalline uniform layer was formed on AlMgSi whenever the concentra-tion of fluoride E(el) which had been electrometrically measured with a fluoride-sensitive electrode was between 80 and 400 mg/l (Examples 4 to 6 and 13 to 20).
After a visual inspection, the layers were covered with a paint by electro-dipcoating and with a coating structure as is used on automobiles and were subjected to the conventional tests o~ application technology. Excellent test results were obtained in all cases in which crystalline layer~ had been ~ormed on the metal substrate.
t ~
13.~3147 Table ExampleNo. 1 2 3 4 5 Zn (g/l) 0.5 0 5 0.8 more than 0.8 0.8 Mg (g/l) 1 1 1 1 2.5 Ni (g/l) 0.1 0.7 0.1 0.7 0.1 Na (g/l) 1.6 0.8 2.0 1.7 0.6 P2O5(g/1) 12 12 14 14 14 NO3 (g/l) 2 Cl (g/l) 0.1~ 0.2 C103 (g/l) 1 1.3 2 NaNo2(g/l) 0.1 0.1 0.1 Nitrobenzene i5 sulfonate (g/l) 0.3 0.3 F(el) (g/l) 0.15 0.1 SiF6 (g/l) Free acid 0.4 0.4 0.8 0.8 0.7 Total acid 17.6 18.6 21.2 22.2 21.8 ~0 free acid 0.02 0.02 0.04 0.04 0.03 total acid Application 2) Spr Spr Spr Spr Spr ~5 3) Galvanized Steel good good good good good AlMgSi 3) _ good good Explanations 1) ~ Additional enriching with Cl by a reduction of chlorate during the processing B
I
13.3314-~
2) Spr = spraying Dp = dipping SD = spraying-dipping 3) Quality of layer:
good = uniformly covering, good phosphate layer (good) = as before, but an occurrence of local crys-talline efflorences (stipples) is possible - = a crystal layer has not been formed on AlMgSi Table (continued) Example No. 6 7 8 9 10 Zn (g/l) 0.8 1.4 1.4 1.4 1.4 Mg (g/l) 2.5 1 1 2.5 2.5 Ni (g/l) 0.7 0.3 0.7 0.3 0.7 Na (g/l) 0.3 1.4 1.9 0.6 P205 (g/l) 14 15 15 15- 15 N03 (g/l) 3 4 Cl (g/l) 1) 0.3~ 0.4~ 2~
C103 (g/l) 1 3 2 NaN02 (g/l) 0.1 0.1 0.1 0.1 Nitrobenzene sulfonate (g/l) 0.3 F(el) (g/l) 0.15 siF6 (g/l) Free acid 0.7 1.6 1.6 1.3 2.5 Total acid 22.8 24.5 25.1 24.9 29.0 free acid 0.3 0.07 0.06 0.05 0.09 total acid Application 2) Spr SD Dp SD Dp 2~
Galvanized steel 3) (good) good good good good AlMgSi ) good - - - -~ 333 ~ 41 Table (continued) ExamDle No. 11 12 13 14 Zn (g/l) 1.4 1.4 1.8 1.8 1.8 Mg (g/l) 4 4 Ni (g/l) 0.3 0.7 0.1 0.3 0.7 Na (g/l) 0.3 0.5 2.4 1.6 1.7 P2O5 (g/l) 15 15 15 15 15 NO3 (g/l) 11 Cl (g/l)lJ 0.2~ 7~ 0.2~
C103 (g/l) 1 1.5 1.5 NaNO2 (g/l) 0.1 0.1 0.1 Nitrobenzene sulfonate (g/l) 0.4 0.4 F(el) (g/l) 0.15 0.15 0.15 SiF6 (g/l) 0.8 0.8 0.8 1.2 Free acid 2.1 2.1 3.3 2.1 4.8 Total acid 28.7 29.4 28.6 25.5 32.2 free acid 0.07 0.07 0.12 0.08 0.15 total acid Application ) Dp Dp Dp Dp Dp Galvanized steel 3) (good) goodgood good good AlMgSi 3 - - good good good 13~3147 Table (continued) Example No. 16 17 18 19 20 Zn (g/l) 1.8 1.8 1.8 1.8 1.8 Mg (g/l) 1 3 3 3 5 Ni (g/l) 1.5 0.1 0.7 1.5 Na (g/l) 1.1 0.5 0.5 P2O5 (g/l) 15 15 15 . 15 18 NO3 (g/l) 6 8 15 Cl (g/l) 0.2~ 0.2~ 4.2 C103 (g/l) 1.5 1.5 ` 1.5 NaNO2 (g/l) 0.1 0.1 0.1 Nitrobenzene sulfonate (g/l) 0.4 0.4 F(el) (g/l) . 0.15 0.15 0.15 0.15 0.15 SiF6 (g/l) 0.8 Free acid 2.1 1.6 1.6 2.8 1.5 Total acid 27.5 25.6 26.6 31.4 32.3 free acid total acid 0.08 0.06 0.06 0.09 0.05 Application ) Dp Dp Dp Dp Dp Galvanized steel 3) good good good good good AlMgSi 3) good good good good good
good = uniformly covering, good phosphate layer (good) = as before, but an occurrence of local crys-talline efflorences (stipples) is possible - = a crystal layer has not been formed on AlMgSi Table (continued) Example No. 6 7 8 9 10 Zn (g/l) 0.8 1.4 1.4 1.4 1.4 Mg (g/l) 2.5 1 1 2.5 2.5 Ni (g/l) 0.7 0.3 0.7 0.3 0.7 Na (g/l) 0.3 1.4 1.9 0.6 P205 (g/l) 14 15 15 15- 15 N03 (g/l) 3 4 Cl (g/l) 1) 0.3~ 0.4~ 2~
C103 (g/l) 1 3 2 NaN02 (g/l) 0.1 0.1 0.1 0.1 Nitrobenzene sulfonate (g/l) 0.3 F(el) (g/l) 0.15 siF6 (g/l) Free acid 0.7 1.6 1.6 1.3 2.5 Total acid 22.8 24.5 25.1 24.9 29.0 free acid 0.3 0.07 0.06 0.05 0.09 total acid Application 2) Spr SD Dp SD Dp 2~
Galvanized steel 3) (good) good good good good AlMgSi ) good - - - -~ 333 ~ 41 Table (continued) ExamDle No. 11 12 13 14 Zn (g/l) 1.4 1.4 1.8 1.8 1.8 Mg (g/l) 4 4 Ni (g/l) 0.3 0.7 0.1 0.3 0.7 Na (g/l) 0.3 0.5 2.4 1.6 1.7 P2O5 (g/l) 15 15 15 15 15 NO3 (g/l) 11 Cl (g/l)lJ 0.2~ 7~ 0.2~
C103 (g/l) 1 1.5 1.5 NaNO2 (g/l) 0.1 0.1 0.1 Nitrobenzene sulfonate (g/l) 0.4 0.4 F(el) (g/l) 0.15 0.15 0.15 SiF6 (g/l) 0.8 0.8 0.8 1.2 Free acid 2.1 2.1 3.3 2.1 4.8 Total acid 28.7 29.4 28.6 25.5 32.2 free acid 0.07 0.07 0.12 0.08 0.15 total acid Application ) Dp Dp Dp Dp Dp Galvanized steel 3) (good) goodgood good good AlMgSi 3 - - good good good 13~3147 Table (continued) Example No. 16 17 18 19 20 Zn (g/l) 1.8 1.8 1.8 1.8 1.8 Mg (g/l) 1 3 3 3 5 Ni (g/l) 1.5 0.1 0.7 1.5 Na (g/l) 1.1 0.5 0.5 P2O5 (g/l) 15 15 15 . 15 18 NO3 (g/l) 6 8 15 Cl (g/l) 0.2~ 0.2~ 4.2 C103 (g/l) 1.5 1.5 ` 1.5 NaNO2 (g/l) 0.1 0.1 0.1 Nitrobenzene sulfonate (g/l) 0.4 0.4 F(el) (g/l) . 0.15 0.15 0.15 0.15 0.15 SiF6 (g/l) 0.8 Free acid 2.1 1.6 1.6 2.8 1.5 Total acid 27.5 25.6 26.6 31.4 32.3 free acid total acid 0.08 0.06 0.06 0.09 0.05 Application ) Dp Dp Dp Dp Dp Galvanized steel 3) good good good good good AlMgSi 3) good good good good good
Claims (7)
1. A process of phosphating metal surfaces of galvanized steel and heterogeneous surfaces of galvanized steel and aluminum, before painting, wherein said metal surfaces are contacted at a temperature between 40 and 60°C
with an aqueous zinc-magnesium phosphating solution which contains 0.4 to 5.0 g/l Mg 0.05 to 2.0 g/l Ni 8 to 20 g/l P2O5 and at least one oxidizing agent and wherein the ratio of free acid to total acid is (0.02 to 0.15) : 1, and with the proviso that a) when the metal surface to be phosphated is a metal surface of galvanized steel, the zinc concentration of the phosphating solution is adjusted to a value in the range of 0.4 to 1.0 g/l when applied in a spraying process, and to a value in the range of 0.9 to 1.5 g/l when applied in a spraying-dipping or dipping process b) when the metal surface to be phosphated is a heterogeneous metal surface of galvanized steel and aluminum, the zinc concentration of the phosphating solution is adjusted to a value varying between more than 0.8 to 1.0 g/l when applied in a spraying process, and to a value in the range of 1.4 to 2.0 g/l when applied in a spraying-dipping or dipping process, and the phosphating solutions contain additionally 80 to 400 mg/l fluoride "F(el)" as determined with a fluoride-sensitive electrode which is immersed into the bath solution.
with an aqueous zinc-magnesium phosphating solution which contains 0.4 to 5.0 g/l Mg 0.05 to 2.0 g/l Ni 8 to 20 g/l P2O5 and at least one oxidizing agent and wherein the ratio of free acid to total acid is (0.02 to 0.15) : 1, and with the proviso that a) when the metal surface to be phosphated is a metal surface of galvanized steel, the zinc concentration of the phosphating solution is adjusted to a value in the range of 0.4 to 1.0 g/l when applied in a spraying process, and to a value in the range of 0.9 to 1.5 g/l when applied in a spraying-dipping or dipping process b) when the metal surface to be phosphated is a heterogeneous metal surface of galvanized steel and aluminum, the zinc concentration of the phosphating solution is adjusted to a value varying between more than 0.8 to 1.0 g/l when applied in a spraying process, and to a value in the range of 1.4 to 2.0 g/l when applied in a spraying-dipping or dipping process, and the phosphating solutions contain additionally 80 to 400 mg/l fluoride "F(el)" as determined with a fluoride-sensitive electrode which is immersed into the bath solution.
2. A process according to claim 1, wherein the metal surfaces are contacted with phosphating solutions which contain nitrate, nitrite, chlorate, bromate, peroxide or nitrobenzene sulfuonate as an oxidizing agent.
3. A process according to claim 1, wherein the metal surfaces are contacted with phosphating solutions which contain nitrate, nitrite, chlorate, bromate, peroxide and nitrobenzene sulfuonate as an oxidizing agent.
4. A process according to claim 1, 2 or 3, wherein in the treatment with phosphating solutions which contain the three components consisting of chloride and/or bromide, nitrate and nickel, at least one of the three components is at a concentration not in excess of 0.1 g/l.
5. A process according to claim 2 or 3, wherein in the metal surfaces are contacted with phosphating solutions which contain the simple or complex fluoride.
6. A process according to claim 1, 2 or 3, wherein in the phosphated metal surfaces belong to work-pieces that are subsequently electro-dipcoated.
7. A process according to claim 1 or 2, wherein in the phosphated metal surfaces belong to workpieces that are subsequently cathodically electro-dipcoated.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3727613 | 1987-08-19 | ||
| DEP3727613.1 | 1987-08-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1333147C true CA1333147C (en) | 1994-11-22 |
Family
ID=6334038
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000574254A Expired - Fee Related CA1333147C (en) | 1987-08-19 | 1988-08-09 | Process of phosphating steel and/or galvanized steel before painting |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0304108B1 (en) |
| JP (1) | JP2680618B2 (en) |
| CA (1) | CA1333147C (en) |
| DE (1) | DE3871031D1 (en) |
| ES (1) | ES2036666T3 (en) |
| GB (1) | GB2208876B (en) |
| ZA (1) | ZA886167B (en) |
Families Citing this family (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3828676A1 (en) * | 1988-08-24 | 1990-03-01 | Metallgesellschaft Ag | PHOSPHATING PROCESS |
| JPH03107469A (en) * | 1989-09-21 | 1991-05-07 | Nippon Parkerizing Co Ltd | Zinc plated material having phosphate chemical conversion coating film excellent in bare corrosion resistance |
| KR100197145B1 (en) * | 1989-12-19 | 1999-06-15 | 후지이 히로시 | Method for phosphating metal surface with zinc phosphate |
| JP2695963B2 (en) * | 1990-03-16 | 1998-01-14 | マツダ株式会社 | Phosphating of metal surfaces |
| DE4131382A1 (en) * | 1990-09-21 | 1992-03-26 | Kobe Steel Ltd | Surface treated aluminium@ alloy sheet for motor car construction - used in making decorative coloured items, zinc phosphate layer having fine grained structure of uniform thickness |
| US5144611A (en) * | 1990-10-01 | 1992-09-01 | International Business Machines Corporation | Optical disk drive cleaner cartridge |
| US5454882A (en) * | 1992-01-13 | 1995-10-03 | Henkel Corporation | Process for controlling a fluoride containing conversion coating forming composition during its use for conversion coating aluminum containing metal |
| JP3181658B2 (en) * | 1992-01-13 | 2001-07-03 | 日本パーカライジング株式会社 | Determination method of effective fluorine concentration in acid chemical conversion treatment of metallic materials |
| JPH05306497A (en) | 1992-04-30 | 1993-11-19 | Nippondenso Co Ltd | Phophatizing chemical conversion treatment |
| DE4306446A1 (en) * | 1993-03-02 | 1994-09-08 | Metallgesellschaft Ag | Procedures to facilitate cold forming |
| JPH07173643A (en) * | 1993-12-21 | 1995-07-11 | Mazda Motor Corp | Method for phosphating metal surface and phosphating solution |
| US5478413A (en) * | 1994-12-27 | 1995-12-26 | Sermatech International, Inc. | Environmentally friendly coating compositions |
| US5797987A (en) * | 1995-12-14 | 1998-08-25 | Ppg Industries, Inc. | Zinc phosphate conversion coating compositions and process |
| DE19606018A1 (en) * | 1996-02-19 | 1997-08-21 | Henkel Kgaa | Zinc phosphating with low levels of nickel and / or cobalt |
| US6413588B1 (en) | 1999-01-11 | 2002-07-02 | E. I. Du Pont De Nemours And Company | Method of producing durable layered coatings |
| DE19921135A1 (en) * | 1999-05-07 | 2000-11-09 | Henkel Kgaa | Process for low-zinc zinc phosphating followed by water treatment |
| JP4658339B2 (en) * | 2001-01-17 | 2011-03-23 | 日本ペイント株式会社 | Metal surface treatment method |
| DE102005059314B4 (en) * | 2005-12-09 | 2018-11-22 | Henkel Ag & Co. Kgaa | Acid, chromium-free aqueous solution, its concentrate, and a process for the corrosion protection treatment of metal surfaces |
| SG176435A1 (en) | 2006-10-31 | 2011-12-29 | Jfe Steel Corp | Phosphate-treated galvanized steel sheet and method for making the same |
| JP5119864B2 (en) * | 2006-10-31 | 2013-01-16 | Ｊｆｅスチール株式会社 | Phosphate-treated galvanized steel sheet and method for producing the same |
| 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 |
| JP2007314888A (en) * | 2007-07-17 | 2007-12-06 | Toyota Motor Corp | Multilayer coating structure |
| ES2397997B1 (en) * | 2010-03-22 | 2014-01-17 | Roberto Ruiz Sanz | DEPOSIT BY PASS FOR COMPRESSED AIR. |
| CN102430506A (en) * | 2011-12-15 | 2012-05-02 | 江苏腾奇电力设备科技有限公司 | Painting process for radiator casting |
| KR101830508B1 (en) * | 2016-06-24 | 2018-02-21 | 주식회사 포스코 | Phosphate-treated zinc-based plated steel sheet having excellent discoloration resistance and film adhesiveness |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB648888A (en) * | 1947-04-25 | 1951-01-17 | Walterisation Company Ltd | Improvements in the production of phosphate coatings on metal surfaces |
| US3597283A (en) * | 1969-10-08 | 1971-08-03 | Lubrizol Corp | Phosphating solutions for use on ferrous metal and zinc surfaces |
| US3676224A (en) * | 1970-10-16 | 1972-07-11 | Lubrizol Corp | Phosphating solution with scale suppressing characteristics |
| DE2327304C3 (en) * | 1973-05-29 | 1982-01-21 | Metallgesellschaft Ag, 6000 Frankfurt | Process for applying phosphate coatings to metals |
| JPS5165041A (en) * | 1974-12-04 | 1976-06-05 | Nippon Packaging Kk | Kinzokuno rinsanenhimakukeiseihoho |
| US4529451A (en) * | 1983-01-03 | 1985-07-16 | Detrex Chemical Industries, Inc. | Zinc phosphate coated metal and process of producing same |
| DE3311738A1 (en) * | 1983-03-31 | 1984-10-04 | Metallgesellschaft Ag, 6000 Frankfurt | METHOD FOR PHOSPHATING METAL SURFACES |
| WO1985003089A1 (en) * | 1984-01-06 | 1985-07-18 | Ford Motor Company | Alkaline resistance phosphate conversion coatings |
| DE3408577A1 (en) * | 1984-03-09 | 1985-09-12 | Metallgesellschaft Ag, 6000 Frankfurt | METHOD FOR PHOSPHATING METALS |
| US4595424A (en) * | 1985-08-26 | 1986-06-17 | Parker Chemical Company | Method of forming phosphate coating on zinc |
| DE3630246A1 (en) * | 1986-09-05 | 1988-03-10 | Metallgesellschaft Ag | METHOD FOR PRODUCING PHOSPHATE COVER AND ITS APPLICATION |
-
1988
- 1988-07-26 ES ES198888201613T patent/ES2036666T3/en not_active Expired - Lifetime
- 1988-07-26 EP EP88201613A patent/EP0304108B1/en not_active Expired - Lifetime
- 1988-07-26 DE DE8888201613T patent/DE3871031D1/en not_active Expired - Lifetime
- 1988-08-09 CA CA000574254A patent/CA1333147C/en not_active Expired - Fee Related
- 1988-08-12 JP JP63200322A patent/JP2680618B2/en not_active Expired - Lifetime
- 1988-08-19 ZA ZA886167A patent/ZA886167B/en unknown
- 1988-08-19 GB GB8819791A patent/GB2208876B/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| ZA886167B (en) | 1990-04-25 |
| GB2208876A (en) | 1989-04-19 |
| JP2680618B2 (en) | 1997-11-19 |
| JPS6468481A (en) | 1989-03-14 |
| EP0304108B1 (en) | 1992-05-13 |
| ES2036666T3 (en) | 1993-06-01 |
| EP0304108A1 (en) | 1989-02-22 |
| GB8819791D0 (en) | 1988-09-21 |
| DE3871031D1 (en) | 1992-06-17 |
| GB2208876B (en) | 1991-08-14 |
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