CA1199559A - Process for the treatment of aluminum surfaces - Google Patents
Process for the treatment of aluminum surfacesInfo
- Publication number
- CA1199559A CA1199559A CA000437827A CA437827A CA1199559A CA 1199559 A CA1199559 A CA 1199559A CA 000437827 A CA000437827 A CA 000437827A CA 437827 A CA437827 A CA 437827A CA 1199559 A CA1199559 A CA 1199559A
- Authority
- CA
- Canada
- Prior art keywords
- ions
- zirconium
- titanium
- solution
- fluoride
- 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
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/34—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides
- C23C22/36—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides containing also phosphates
- C23C22/361—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 titanium, zirconium or hafnium compounds
-
- 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
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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)
- Application Of Or Painting With Fluid Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
In a process for the application of conversion coatings to aluminum surfaces, solutions are used which contain titanium and/or zirconium, fluoride and phosphate ions, but which are free from nitrate, nitrite, and chromium ions and also from organic film-forming polymers and tannin.
In order to avoid wastewater treatment problems and also difficulties in a succession of treatments, the aluminum surfaces are brought into contact with a solution which has a pH value of at most 3.5 and which contains at least 1 g/l of zirconium ions and/or at least 0.5 g/l of titanium ions and also at least 1.5 g/l of phosphate ions. The molar ratio of phosphate ions to zirconium and/or titanium ions is to be at least 0.5, and that of fluoride ions to zirconium and/or titanium ions at least 5, in the solution. The composition of the film of solution applied is to be selected such that a film weight of 10 - 300, preferably 20 - 200, mg/m2 results on subsequent drying out.
Molar ratios of phosphate ions to zirconium and/or titanium ions of at most 5, and of fluoride ions to zirconium and/or titanium ions of at most 15, are preferred.
In a process for the application of conversion coatings to aluminum surfaces, solutions are used which contain titanium and/or zirconium, fluoride and phosphate ions, but which are free from nitrate, nitrite, and chromium ions and also from organic film-forming polymers and tannin.
In order to avoid wastewater treatment problems and also difficulties in a succession of treatments, the aluminum surfaces are brought into contact with a solution which has a pH value of at most 3.5 and which contains at least 1 g/l of zirconium ions and/or at least 0.5 g/l of titanium ions and also at least 1.5 g/l of phosphate ions. The molar ratio of phosphate ions to zirconium and/or titanium ions is to be at least 0.5, and that of fluoride ions to zirconium and/or titanium ions at least 5, in the solution. The composition of the film of solution applied is to be selected such that a film weight of 10 - 300, preferably 20 - 200, mg/m2 results on subsequent drying out.
Molar ratios of phosphate ions to zirconium and/or titanium ions of at most 5, and of fluoride ions to zirconium and/or titanium ions of at most 15, are preferred.
Description
5~
Case No.: P-11,130 PROCESS FOR THE SURFACE TREATMENT OF ALUMINUM
, The invention relates to a process for the application of conversion coatings to aluminum surfaces by means of solutions which contain titanium and/or zirconium, and also fluoride and phosphate ions, but which are free from nitrate, nitrite, and chromium ions and also from organic film-forming polymers and tannin.
Background of the Invention ~ _ , . .... .
For the chemical treatment of metals, for example as pretreatment for the application of lacquers, adhesives and plastics, processes are known in which the metal surface is cleaned in the first stage, is flushed with water in the second stage, and is then finally wetted in the third stage with an aqueous solution which forms chemical conversion coatings, and the resulting liquid film is then dried.
A thin, non metallic coating is thus formed on the metal, and can decisively improve the surface quality when the composition of the treatment liquid and the reaction conditions are correspondingly selected.
Thus, e.g., coatings of lacquers, adhesives and plastics, if necessary in the form of foils, can be distinguished by substantially greater adhesion and a markedly increased corrosion protection, when they are applied to metals pretreated in this way.
,,~
S'~
Such processes operate, e.g., with an aqueous solution which contains hexavalent chromium, trivalent chromium, alkali ions, and silicon dioxide in given proportions and produces coatings for electrical insulation, for corrosion protection, and as an adhesion base for lacquers and the like (DE-AS
1,769,5~2).
Coatings can also be produced on metallic surfaces by means of coating media which contain a compound of hexavalent chromium and a polymeric organic material (so-called primer) and are then drie~ or stoved (AP-PS 197,164).
Because of the presence of hexavalent chromium, the disadvantage is common to the above-mentioned processes that precautionary measures have to be taken, in particular during the application of the coating material and the handling of the coated metal, and that effects on the contents cannot be excluded when such coated metals are used as container material for foodstuffs and beverages.
In order to avoid the disadvantages connected with the use of treatment liquids containing hexavalent chromium, it is furthermore known to wet the cleaned metal surfaces, in particular of iron, zinc, and aluminum, with an acid aqueous solution which contains chromium-III ions, phosphate ions, and finely-divided silicic acid, and possibly also acetate, 5~i~
maleate, zinc, and/or manganese ions, and to dry the film of solution (DE-OS 2,711,431). Although this process has considerable advantages over the above-mentloned ones, it is disadvantageous that when the coated metals are used as container material a certain effect on foodstuffs and beverages due to the chromium~III content cannot be completely excluded, and that the treatment liquid tends to be unstable due to the formation of difficultly soluble chromium phosphate.
Another category of processes for the application of conversion coatings, specially for aluminum surfaces, proposes dip or spray treatment with compositions which contain given amounts of zirconium and/or titanium and also phosphate and active fluoride (U.S. Patent 4,148,670) or polyacrylic acid or ester and fluozirconic acid, fluotitanic acid or fluosilicic acid (U.SO Patent 4,191,596) or tannin together with titanium and fluorine ions (U.S. Patent 4,054,46S)` or also complex fluorides or boron, titanium, or zirconium, together with oxidants such as sodium meta-nitrobenzenesulfonate (DE-AS 1,933,013).
~he last-named processes are disadvantageous in that because of water-soluble components of the coating medium a rinse treatment is required, which often leads to a waste water which is difficult to treat, or else only a comparatively complicated monitoring o the bath leads to usable results.
5~i~
Tannin-containing coating media sometimes lead to an undesired discoloration of the treated metal surfaces.
Because of the multiplicity of known tannins, the coating media are also reproducible only with difficulty as regards their action. Polymer-containing coating media tend to ageing of the polymer and to instability, particularly in the form of concentrates.
In particular~ also, a certain incompatibility with organic coatings which are then applied can be foreseenO
The object of the invention is to make available a process for the application of conversion coatings to aluminum surfaces which avoids the known disadvantages, in particular those mentioned above, and can be carried out without additional cost.
Summary of the Invention The problem is solved in that the procèss of the kind mentioned at the beginning is designed according to the invention such that the aluminum surface is brought in contact with a solution which has a pH of at most 3.5 and contains fluoride ions, at least 1 g/l zirconium ions and/or at least 0.5 g/l titanium ions and also at least 1.5 g/l phosphate ions, in which the molar ratio of phosphate ions to zirconium and/or titanium ions is at least 0.5 and of fluoride ions to zirconium and/or titanium ions is at least 5, such that when the liquid film is subsequently dried a film weight of 10 - 300 mg/m2 results.
5~g The solution can be brought into contact with the aluminum surface in any conventional way, such as dipping and subsequently allowing to drip off, pouring over and centrifuging off, brushing, spraying with use of one- or two-material nozzles, spraying or rolling on with flat or configured rollers running in the same or opposite directions. Rolling-on processes, because of the comparatively precise metering of the amounts of solution, are particularly suitable.
The application of an amount of solution of about 3 - 20 ml/m2 of aluminum surface is particularly advantageous. Because of the small amount of water to be evaporated off, the amounts of solution should be as far as possible in the lower part of the range .
The drying of the solution film applied to the aluminum surface can basically take place already at room temperature. For better formation of the conversion coating, however, higher temperatures~
preferably of 50 - 120~C - given as temperature of the article - are recommended.
Detailed Description of the Invention According to a preferred improvement of the invention, the aluminum surface is brought into contact with a solution in which the molar ratio of phosphate ions to ~irconium and/or titanium ions is at mos~ 5, In this way a satisfactory film formation is ensured on the one hand, and on the other hand the precipitation of difficultly soluble zirconium phosphate is prevented.
Furthermore, it is advantageous to bring the aluminum surface into contact with a solution in which the molar ratio of fluoride to zirconium and/or titanium ions is at most 15. The increased supply of fluoride accelerates the reaction taking place on the aluminum surface. In addition, a concentration of phosphate which is advantageous ~or the above-mentioned satisfactory film formation can be faultlessly stabilized.
As regards a subsequent treatment by application of an organic coating, optimum results are achieved when~ in a further advantageous embodiment of the invention, the aluminum surface is brought into contact with a solution such that a film weight of 20 -200 mg/m2 results.
Before the process according to the invention is carried out, thè aluminum surfaces are to be thoroughly cleaned. The cleaning can take place with acid cleaners based on phosphoric acid or sulfuric acid, which should also contain surfactant, in particular of the nonionic type, and possibly also fluoride, or also with strongly alkaline cleaners, e.g., with a content of sodium hydroxide, condensed _~_ r- ~
phosphate, and surfactant. Rinsing thoroughly with water should then follow, most suitably with fully desalted water in the last stage. According to the nature of the contamination, degreasing with, or supplementarily with, halogenated hydrocarbons can also be carried out.
The invention is explained, by way of example and in more detail, with reference to the Examples.
Examples Aluminum sheets of dimension 100 x 200 mm were cleaned at 65C for 15 sec by dipping in a strongly alkaline cleaner based on caustic soda, condensed phosphate, and non-ionic surfactant, rinsed thoroughly with water, and freed from excess rinse water by squeeze rolling. The cleaned aluminum sheets were then dipped for about 1 sec in the treatment`
solution at reaction temperature and guided between fluted rollers or smooth rollers such that 6 or 3 ml solution film per m2 Of aluminum surface remained.
The drying of the solution took place at 80C article temperature.
The solutions used, which all had a pH in the range 1~5 - 2.0 had the constitution summarized in the following table~ The data on amounts of chemicals s~
used or on the titanium and zirconium content are in g/l.
5Solution H~TiF~H~ZrF~ ~ NH4F
1 5.30 - 4.15 3.60
Case No.: P-11,130 PROCESS FOR THE SURFACE TREATMENT OF ALUMINUM
, The invention relates to a process for the application of conversion coatings to aluminum surfaces by means of solutions which contain titanium and/or zirconium, and also fluoride and phosphate ions, but which are free from nitrate, nitrite, and chromium ions and also from organic film-forming polymers and tannin.
Background of the Invention ~ _ , . .... .
For the chemical treatment of metals, for example as pretreatment for the application of lacquers, adhesives and plastics, processes are known in which the metal surface is cleaned in the first stage, is flushed with water in the second stage, and is then finally wetted in the third stage with an aqueous solution which forms chemical conversion coatings, and the resulting liquid film is then dried.
A thin, non metallic coating is thus formed on the metal, and can decisively improve the surface quality when the composition of the treatment liquid and the reaction conditions are correspondingly selected.
Thus, e.g., coatings of lacquers, adhesives and plastics, if necessary in the form of foils, can be distinguished by substantially greater adhesion and a markedly increased corrosion protection, when they are applied to metals pretreated in this way.
,,~
S'~
Such processes operate, e.g., with an aqueous solution which contains hexavalent chromium, trivalent chromium, alkali ions, and silicon dioxide in given proportions and produces coatings for electrical insulation, for corrosion protection, and as an adhesion base for lacquers and the like (DE-AS
1,769,5~2).
Coatings can also be produced on metallic surfaces by means of coating media which contain a compound of hexavalent chromium and a polymeric organic material (so-called primer) and are then drie~ or stoved (AP-PS 197,164).
Because of the presence of hexavalent chromium, the disadvantage is common to the above-mentioned processes that precautionary measures have to be taken, in particular during the application of the coating material and the handling of the coated metal, and that effects on the contents cannot be excluded when such coated metals are used as container material for foodstuffs and beverages.
In order to avoid the disadvantages connected with the use of treatment liquids containing hexavalent chromium, it is furthermore known to wet the cleaned metal surfaces, in particular of iron, zinc, and aluminum, with an acid aqueous solution which contains chromium-III ions, phosphate ions, and finely-divided silicic acid, and possibly also acetate, 5~i~
maleate, zinc, and/or manganese ions, and to dry the film of solution (DE-OS 2,711,431). Although this process has considerable advantages over the above-mentloned ones, it is disadvantageous that when the coated metals are used as container material a certain effect on foodstuffs and beverages due to the chromium~III content cannot be completely excluded, and that the treatment liquid tends to be unstable due to the formation of difficultly soluble chromium phosphate.
Another category of processes for the application of conversion coatings, specially for aluminum surfaces, proposes dip or spray treatment with compositions which contain given amounts of zirconium and/or titanium and also phosphate and active fluoride (U.S. Patent 4,148,670) or polyacrylic acid or ester and fluozirconic acid, fluotitanic acid or fluosilicic acid (U.SO Patent 4,191,596) or tannin together with titanium and fluorine ions (U.S. Patent 4,054,46S)` or also complex fluorides or boron, titanium, or zirconium, together with oxidants such as sodium meta-nitrobenzenesulfonate (DE-AS 1,933,013).
~he last-named processes are disadvantageous in that because of water-soluble components of the coating medium a rinse treatment is required, which often leads to a waste water which is difficult to treat, or else only a comparatively complicated monitoring o the bath leads to usable results.
5~i~
Tannin-containing coating media sometimes lead to an undesired discoloration of the treated metal surfaces.
Because of the multiplicity of known tannins, the coating media are also reproducible only with difficulty as regards their action. Polymer-containing coating media tend to ageing of the polymer and to instability, particularly in the form of concentrates.
In particular~ also, a certain incompatibility with organic coatings which are then applied can be foreseenO
The object of the invention is to make available a process for the application of conversion coatings to aluminum surfaces which avoids the known disadvantages, in particular those mentioned above, and can be carried out without additional cost.
Summary of the Invention The problem is solved in that the procèss of the kind mentioned at the beginning is designed according to the invention such that the aluminum surface is brought in contact with a solution which has a pH of at most 3.5 and contains fluoride ions, at least 1 g/l zirconium ions and/or at least 0.5 g/l titanium ions and also at least 1.5 g/l phosphate ions, in which the molar ratio of phosphate ions to zirconium and/or titanium ions is at least 0.5 and of fluoride ions to zirconium and/or titanium ions is at least 5, such that when the liquid film is subsequently dried a film weight of 10 - 300 mg/m2 results.
5~g The solution can be brought into contact with the aluminum surface in any conventional way, such as dipping and subsequently allowing to drip off, pouring over and centrifuging off, brushing, spraying with use of one- or two-material nozzles, spraying or rolling on with flat or configured rollers running in the same or opposite directions. Rolling-on processes, because of the comparatively precise metering of the amounts of solution, are particularly suitable.
The application of an amount of solution of about 3 - 20 ml/m2 of aluminum surface is particularly advantageous. Because of the small amount of water to be evaporated off, the amounts of solution should be as far as possible in the lower part of the range .
The drying of the solution film applied to the aluminum surface can basically take place already at room temperature. For better formation of the conversion coating, however, higher temperatures~
preferably of 50 - 120~C - given as temperature of the article - are recommended.
Detailed Description of the Invention According to a preferred improvement of the invention, the aluminum surface is brought into contact with a solution in which the molar ratio of phosphate ions to ~irconium and/or titanium ions is at mos~ 5, In this way a satisfactory film formation is ensured on the one hand, and on the other hand the precipitation of difficultly soluble zirconium phosphate is prevented.
Furthermore, it is advantageous to bring the aluminum surface into contact with a solution in which the molar ratio of fluoride to zirconium and/or titanium ions is at most 15. The increased supply of fluoride accelerates the reaction taking place on the aluminum surface. In addition, a concentration of phosphate which is advantageous ~or the above-mentioned satisfactory film formation can be faultlessly stabilized.
As regards a subsequent treatment by application of an organic coating, optimum results are achieved when~ in a further advantageous embodiment of the invention, the aluminum surface is brought into contact with a solution such that a film weight of 20 -200 mg/m2 results.
Before the process according to the invention is carried out, thè aluminum surfaces are to be thoroughly cleaned. The cleaning can take place with acid cleaners based on phosphoric acid or sulfuric acid, which should also contain surfactant, in particular of the nonionic type, and possibly also fluoride, or also with strongly alkaline cleaners, e.g., with a content of sodium hydroxide, condensed _~_ r- ~
phosphate, and surfactant. Rinsing thoroughly with water should then follow, most suitably with fully desalted water in the last stage. According to the nature of the contamination, degreasing with, or supplementarily with, halogenated hydrocarbons can also be carried out.
The invention is explained, by way of example and in more detail, with reference to the Examples.
Examples Aluminum sheets of dimension 100 x 200 mm were cleaned at 65C for 15 sec by dipping in a strongly alkaline cleaner based on caustic soda, condensed phosphate, and non-ionic surfactant, rinsed thoroughly with water, and freed from excess rinse water by squeeze rolling. The cleaned aluminum sheets were then dipped for about 1 sec in the treatment`
solution at reaction temperature and guided between fluted rollers or smooth rollers such that 6 or 3 ml solution film per m2 Of aluminum surface remained.
The drying of the solution took place at 80C article temperature.
The solutions used, which all had a pH in the range 1~5 - 2.0 had the constitution summarized in the following table~ The data on amounts of chemicals s~
used or on the titanium and zirconium content are in g/l.
5Solution H~TiF~H~ZrF~ ~ NH4F
1 5.30 - 4.15 3.60
2 7.85 - 3.18 1.77
3 10.20 - 4.14 2.30
4 - 6.03 3.68 3.23 - 8.46 2.72 1.51 6 - 6.66 2.14 1.89 Molar Ratios 15Solution Ti Zr PO4 : Ti or ZrF : Ti or Zr l ~.54 - 1.35 9.0 2 2.28 - 0.70 7.0 3 2.96 - 0.70 7.0 4 - 2.65 1.33 g.0 - 3.72 0.70 7.0 6 - 2.93 0.70 7.6 Amount of Solution Film Weight 25SolutionApplied in ml _ Produced in mg/m2
5~
Sheets were used for comparison which had been treated with a solution containing 5 g/l of chromic acid and 5 g/l of silicic acid (in the form of Aerosil) (denoted Solution A), or sheets were taken which had only been degreased and rinsed with fully desalted water (denoted Solution s below).
After application of the conversion coating, the aluminum sheets were subjected to several tests.
Within a first test series, the aluminum sheets provided with the conversion coating were lacquered with an epoxy lacquer (~obil SHX 2636) and the lacquer adhesion was tested by the T-bend test.
A second series of aluminum sheets was provided with a gold lacquer and after the boiling test was subjected to a test of blister formation, discoloration, and lacquer shedding.
In a third series of aluminum sheets, a hard PVC sheet was sealed on by means of a PVC-based heat-seal lacquer, and the adhesion of the sheet was determined by the peel test.
The test procedure is explained below:
In the T-bend test, the lacquered sheet was bent 180. The radius of the bend results ~rom the selection of the cushion acting as a mandrel. ~sually _9~
one or more sheets are used of the same thickness as the test sheet. For the severest stressing, operation is without a cushion and the sheet is bent until the untreated sides touch (so-called T-O-bending). Bending over one sheet is denoted as T-1-bending, over two sheets as T-2-bending. After bending, the lacquer adhesion is determined by application and removal of adhes ve tape in the region of the place stressed by bending.
In the tables given below, the test results are given for loosening of lacquer for the T-bending test in percent -- with respect to the point of bending.
The boiling test consists of first boiling the lacquered aluminum sheets for 3 hours in completely desalted water and then judging blister formation and discoloration. Here one part of the sheets is subjected before the boiling treatment to a mechanical stressing corresponding to the above-mentioned T-bending test or to impact drawing. In the stressing corresponding to impact drawing, a drop body is allowed to strike the unlacquered side of the sheet from a given heightr shortly after hardening of the lacquer and at room temperature, with a ball-shaped impact part (ball diameter 16.9 mm).
The peeling test is characterized in that the sheet metal strips, or strips provided with a conversion coating, 200 mm long and 15 mm wide, are provide on one side with a sealing lacquer and then provided with a PVC foil by means of heated press jaws at a press pressure oE 300 Newton/cm2, a duration of 4 sec and a temperature of the preheated press jaws of 180C. After storage in water for three days, the adhesion loss in comparison with a sheet not stored in water is determined by pulling the foil off, and is given in percent. The speed at which the foil is pulled off is here 30 mm/min.
The results of the above-mentionecl tests are collected below in a table. It should be added that in the boiling test of the metal sheets provided with a conversion coating, a minimal, hardly detectable discoloration could be observed. In the sheets mechanically stressed as in impact drawing, a slight loosening of lacquer was just detectable. The metal sheets which were only degreated and rinsed with completely desalted water showed complete loosening of lacquer.
Test Results Boiling Test T2-Bending T1-Bending Peeling Solution Test Blisters Test Test
Sheets were used for comparison which had been treated with a solution containing 5 g/l of chromic acid and 5 g/l of silicic acid (in the form of Aerosil) (denoted Solution A), or sheets were taken which had only been degreased and rinsed with fully desalted water (denoted Solution s below).
After application of the conversion coating, the aluminum sheets were subjected to several tests.
Within a first test series, the aluminum sheets provided with the conversion coating were lacquered with an epoxy lacquer (~obil SHX 2636) and the lacquer adhesion was tested by the T-bend test.
A second series of aluminum sheets was provided with a gold lacquer and after the boiling test was subjected to a test of blister formation, discoloration, and lacquer shedding.
In a third series of aluminum sheets, a hard PVC sheet was sealed on by means of a PVC-based heat-seal lacquer, and the adhesion of the sheet was determined by the peel test.
The test procedure is explained below:
In the T-bend test, the lacquered sheet was bent 180. The radius of the bend results ~rom the selection of the cushion acting as a mandrel. ~sually _9~
one or more sheets are used of the same thickness as the test sheet. For the severest stressing, operation is without a cushion and the sheet is bent until the untreated sides touch (so-called T-O-bending). Bending over one sheet is denoted as T-1-bending, over two sheets as T-2-bending. After bending, the lacquer adhesion is determined by application and removal of adhes ve tape in the region of the place stressed by bending.
In the tables given below, the test results are given for loosening of lacquer for the T-bending test in percent -- with respect to the point of bending.
The boiling test consists of first boiling the lacquered aluminum sheets for 3 hours in completely desalted water and then judging blister formation and discoloration. Here one part of the sheets is subjected before the boiling treatment to a mechanical stressing corresponding to the above-mentioned T-bending test or to impact drawing. In the stressing corresponding to impact drawing, a drop body is allowed to strike the unlacquered side of the sheet from a given heightr shortly after hardening of the lacquer and at room temperature, with a ball-shaped impact part (ball diameter 16.9 mm).
The peeling test is characterized in that the sheet metal strips, or strips provided with a conversion coating, 200 mm long and 15 mm wide, are provide on one side with a sealing lacquer and then provided with a PVC foil by means of heated press jaws at a press pressure oE 300 Newton/cm2, a duration of 4 sec and a temperature of the preheated press jaws of 180C. After storage in water for three days, the adhesion loss in comparison with a sheet not stored in water is determined by pulling the foil off, and is given in percent. The speed at which the foil is pulled off is here 30 mm/min.
The results of the above-mentionecl tests are collected below in a table. It should be added that in the boiling test of the metal sheets provided with a conversion coating, a minimal, hardly detectable discoloration could be observed. In the sheets mechanically stressed as in impact drawing, a slight loosening of lacquer was just detectable. The metal sheets which were only degreated and rinsed with completely desalted water showed complete loosening of lacquer.
Test Results Boiling Test T2-Bending T1-Bending Peeling Solution Test Blisters Test Test
6 5 0 5 21
Claims (4)
1. A process for application of conversion coatings to aluminum surfaces by means of solutions which contain titanium and/or zirconium, fluoride and phosphate ions, but which are free from nitrate, nitrite, and chromium ions and also from organic film-forming polymers and tannin, characterized in that the aluminum surfaces are brought into contact with a solutions which has a pH value of at most 3.5 and which contains at least 1 g/l zirconium ions and/or at least 0.5 g/l titanium ions and also at least 1.5 g/l phosphate ions, in which the molar proportions of phosphate ions to zirconium and/or titanium ions is at least 0.5 and of fluoride ions to zirconium and/or titanium ions is at least 5, such that on subsequent drying of the liquid film a film weight of 10 - 300 mg/m2 results.
2. The process according to Claim 1, characterized in that the aluminum surfaces are brought into contact with a solution in which the molar proportion of phosphate ions to zirconium and/or titanium ions is at most 5.
3. The process according to Claim 2, characterized in that the aluminum surfaces are brought into contact with a solution in which the molar proportion of fluoride to zirconium and/or titanium ions is at most 15.
4. The process according to Claim 3, characterized in that the aluminum surfaces are brought into contact with a solution such that a film weight of 20 - 200 mg/m2 results.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3236247.1 | 1982-09-28 | ||
| DE19823236247 DE3236247A1 (en) | 1982-09-30 | 1982-09-30 | METHOD FOR SURFACE TREATMENT OF ALUMINUM |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1199559A true CA1199559A (en) | 1986-01-21 |
Family
ID=6174596
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000437827A Expired CA1199559A (en) | 1982-09-28 | 1983-09-28 | Process for the treatment of aluminum surfaces |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0106389A1 (en) |
| JP (1) | JPS5983776A (en) |
| AU (1) | AU1972083A (en) |
| CA (1) | CA1199559A (en) |
| DE (1) | DE3236247A1 (en) |
| ES (1) | ES8405447A1 (en) |
| GB (1) | GB2131052A (en) |
| ZA (1) | ZA837238B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5904786A (en) * | 1994-12-09 | 1999-05-18 | Metallgesellschaft Aktiengesellschaft | Method of applying phosphate coatings to metal surfaces |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61232151A (en) * | 1985-04-04 | 1986-10-16 | 東洋製罐株式会社 | Bonding can made of aluminum |
| US4881975A (en) * | 1986-12-23 | 1989-11-21 | Albright & Wilson Limited | Products for treating surfaces |
| CA1333043C (en) * | 1988-02-15 | 1994-11-15 | Nippon Paint Co., Ltd. | Surface treatment chemical and bath for aluminium and its alloy |
| JPH0784665B2 (en) * | 1988-03-25 | 1995-09-13 | 日本ペイント株式会社 | Aluminum conversion treatment method |
| GB8828559D0 (en) * | 1988-12-07 | 1989-01-11 | Novamax Tech Corp | Composition & method for coating metal surfaces |
| BR9206419A (en) * | 1991-08-30 | 1995-04-04 | Henkel Corp | Process for the production of a protective conversion coating. |
| GB2259920A (en) * | 1991-09-10 | 1993-03-31 | Gibson Chem Ltd | Surface conversion coating solution based on molybdenum and phosphate compounds |
| US5290625A (en) * | 1992-05-22 | 1994-03-01 | Davidson Textron Inc. | System for making bright aluminum parts |
| JPH0748677A (en) * | 1993-07-05 | 1995-02-21 | Nippon Parkerizing Co Ltd | Aluminum di can and common surface treatment solution and process for tin di can |
| US5603754A (en) * | 1993-07-05 | 1997-02-18 | Henkel Corporation | Composition and process for treating tinplate and aluminum |
| JP2828409B2 (en) * | 1994-03-24 | 1998-11-25 | 日本パーカライジング株式会社 | Surface treatment composition for aluminum-containing metal material and surface treatment method |
| JP3315529B2 (en) * | 1994-06-03 | 2002-08-19 | 日本パーカライジング株式会社 | Composition for surface treatment of aluminum-containing metal material and surface treatment method |
| US5494504A (en) * | 1994-09-12 | 1996-02-27 | Ppg Industries, Inc. | Liquid rinse conditioner for phosphate conversion coatings |
| JP2002266080A (en) * | 2001-03-07 | 2002-09-18 | Nippon Paint Co Ltd | Phosphate chemical conversion treatment solution, chemical conversion treatment method and chemical conversion treated steel sheet |
| AU2003290716A1 (en) * | 2002-11-15 | 2004-06-15 | Henkel Kommanditgesellschaft Auf Aktien | Passivation composition and process for zinciferous and aluminiferous surfaces |
| JP6295832B2 (en) * | 2014-05-28 | 2018-03-20 | 株式会社ブリヂストン | Aluminum-rubber composite and method for producing the same |
| CN108350579A (en) | 2015-09-15 | 2018-07-31 | 凯密特尔有限责任公司 | With the composition pre-treating aluminium surface containing zirconium and molybdenum |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1277644B (en) * | 1962-07-03 | 1968-09-12 | Metallgesellschaft Ag | Methods and solutions for applying coatings to titanium and its alloys |
| US4063969A (en) * | 1976-02-09 | 1977-12-20 | Oxy Metal Industries Corporation | Treating aluminum with tannin and lithium |
| CA1098253A (en) * | 1976-04-05 | 1981-03-31 | Timm L. Kelly | Zirconium/titanium coating solution for aluminum surfaces |
| JPS53125238A (en) * | 1977-04-09 | 1978-11-01 | Nippon Paint Co Ltd | Regenerating method for surface treating liquid for aluminum and its alloy |
| JPS5424232A (en) * | 1977-07-26 | 1979-02-23 | Nippon Packaging Kk | Surface treating method of aluminum |
| FR2417537A1 (en) * | 1978-02-21 | 1979-09-14 | Parker Ste Continentale | COMPOSITION BASED ON HAFNIUM TO INHIBIT CORROSION OF METALS |
| US4187127A (en) * | 1978-12-07 | 1980-02-05 | Nihon Parkerizing Co., Ltd. | Surface processing solution and surface treatment of aluminum or aluminum alloy substrate |
| NZ195810A (en) * | 1979-12-26 | 1983-07-15 | Amchem Prod | Acidic aqueous solution forming a corrosion-resistant coating on aluminium |
| JPS5839232B2 (en) * | 1980-05-12 | 1983-08-29 | 日本パ−カライジング株式会社 | Film chemical conversion treatment solution for aluminum and aluminum alloy surfaces |
-
1982
- 1982-09-30 DE DE19823236247 patent/DE3236247A1/en not_active Withdrawn
-
1983
- 1983-09-16 EP EP83201327A patent/EP0106389A1/en not_active Withdrawn
- 1983-09-28 ZA ZA837238A patent/ZA837238B/en unknown
- 1983-09-28 CA CA000437827A patent/CA1199559A/en not_active Expired
- 1983-09-29 AU AU19720/83A patent/AU1972083A/en not_active Abandoned
- 1983-09-29 JP JP58181798A patent/JPS5983776A/en active Pending
- 1983-09-30 GB GB08326185A patent/GB2131052A/en not_active Withdrawn
- 1983-09-30 ES ES526551A patent/ES8405447A1/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5904786A (en) * | 1994-12-09 | 1999-05-18 | Metallgesellschaft Aktiengesellschaft | Method of applying phosphate coatings to metal surfaces |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2131052A (en) | 1984-06-13 |
| JPS5983776A (en) | 1984-05-15 |
| GB8326185D0 (en) | 1983-11-02 |
| ES526551A0 (en) | 1984-06-16 |
| ZA837238B (en) | 1984-06-27 |
| DE3236247A1 (en) | 1984-04-12 |
| EP0106389A1 (en) | 1984-04-25 |
| ES8405447A1 (en) | 1984-06-16 |
| AU1972083A (en) | 1984-04-05 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |