JPH0433867B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to compositions and methods for treating steel. Non-galvanized and galvanized steel sheets and other components used, for example, in the automotive and building industries, are commonly painted both to protect the steel from rust and for appearance purposes. It is well known that paints do not protect uncoated or galvanized steel surfaces well. That is, the adhesion is poor, paint blisters often occur over time, and corrosion resistance is generally poor. Therefore, both steel surfaces and galvanized steel surfaces are generally protected prior to painting by the formation of a protective coating, such as a zinc phosphate coating.

For many years, previously cleaned and often activated steel or galvanized steel surfaces have been treated with a solution containing zinc ions and phosphoric acid, e.g.
A zinc phosphate film was formed by contacting the materials at a heating temperature of 0.3 °C. The resulting zinc phosphate coatings prove to be very satisfactory for use as paint bases, but with rising energy costs, the energy requirements to maintain the treatment baths at the above-mentioned temperatures are decreasing. It had to become increasingly expensive.

Therefore, a bath with a temperature of 110〓 (43.3℃) or less,
So-called low-temperature baths were developed. However, zinc phosphate coatings obtained from such low temperature baths tend to be coarse and powdery and are generally less satisfactory than zinc phosphate coatings produced from high temperature baths.

A low temperature process and bath formulation has now been discovered that produces coatings on clean and galvanized steel that are comparable in all respects to the zinc phosphate coatings formed from high temperature processes and baths.

Non-galvanized and galvanized steels that can be treated with the method of the present invention include cold rolled steel and other steel structures that are to be painted. For example, cars,
Steel components and parts used in the architectural and mechanical industries are advantageously treated by the compositions and methods of the present invention.

Steel components for treatment in accordance with the present invention can be prepared using methods and compositions well known in the art.
For example, it is prepared by cleaning the surface of steel or galvanized steel by treatment with an alkaline cleaning solution. Typically, the steel or galvanized steel surface is wiped with a degreasing solution, such as an aliphatic hydrocarbon mixture, before the cleaning step. Hereinafter, when the term "steel" is used, unless otherwise stated, it is intended to include both galvanized steel and non-galvanized steel.

If desired, the cleaned steel can then be activated using compositions known in the art or novel compositions that may be utilized in the present invention.

Although the process of the present invention to produce zinc phosphate conversion coatings can be carried out without a prior activation step, activating the steel surface prior to formation of the conversion coating generally results in a denser and more adhesive conversion coating.

Traditional methods of activating cleaned steel generally use aqueous colloidal solutions containing titanium compounds. For example, aqueous colloidal solutions of potassium titanium fluoride and disodium phosphate are often used for this purpose.

The novel activation compositions that may be utilized in the present invention actually provide greater activation to cleaned steel than those produced by prior art compositions and thereby provide phosphate conversion coating solutions. When applied, a dense, uniformly hard and heavy phosphate conversion coating is formed on the surface. The activating compositions that may be utilized in the present invention can be used prior to the formation of phosphate conversion coatings, such as zinc phosphate coatings or known iron-manganese phosphate coatings. Zinc phosphate coatings can be formed using the novel conversion coating methods and compositions of the present invention or conventionally known methods and compositions.

The novel activation composition that may be utilized in the present invention consists of an aqueous colloidal solution of manganese ions and a titanium compound. The manganese ion is at least about 0.005 g/(solution), preferably about
0.025-0.075g/present. Manganese ions may be included in the form of insoluble salts such as manganese phosphate, manganese carbonate, etc., which is the preferred form for use herein. However, although manganese ions may be contained in the form of soluble salts such as chloride, sulfate, fluoride, nitrate, etc., the use of a large amount of soluble salts of manganese will increase the concentration of desired colloids in the solution. It should not exceed about 0.05 g/ml, as it tends to interfere with sex.

In the form of a titanium compound in colloidal suspension,
Titanium ions are contained in an amount of about 0.005 to 0.02 g/, preferably about 0.006 to 0.012 g/. The titanium compound may be any titanium compound that forms a colloidal suspension when added to an aqueous solution in fine powder form. Examples of such titanium compounds include potassium titanium fluoride and potassium titanium oxalate.

Also, alkali metal salts such as alkali metal citrates, phosphates, etc. can be added to the aqueous solution if desired to stabilize the aqueous solution and/or to provide a desired pH. The PH is generally maintained between 7 and 8, but higher PH values, such as about 10, are acceptable.

The novel activating solution is applied to the cleaned steel by standard techniques, such as spraying or dipping the steel in the solution. The solution is about 60~130〓(15.6~54.4
℃), preferably maintained at a temperature of about 70-90㎓ (21.1-32.℃). Processing times are at least about 10 seconds, preferably about 30 seconds to 1 minute.

Upon removing the steel from contact with the activating solution,
It is then immediately treated with a conversion coating solution without rinsing. Preferably, the conversion coating solution and method of the present invention described below are employed.

If desired, the novel activation solution can be combined with known alkaline cleaners;
This allows both cleaning and activating the steel in a single step. The combined cleaning/activation solution is
Contains titanium ions and manganese ions in the same concentrations as mentioned above for activation solutions formulated without alkaline cleaners. The alkaline cleaner components of the combination include alkali metal hydroxide,
It can be an alkaline steel cleaning cleaner containing one or more surfactants, optionally alkali metal silicates and/or other desired ingredients. The combined cleaning/activation solution is approximately 90
~130〓(32.2~54.4℃), preferably about 110~120
〓 (43.3-48.9°C) and a treatment time of about 30 seconds to 2 minutes, preferably about 60-90 seconds. Excess cleaning/activating solution is then removed from the steel, for example by rinsing the steel with water, prior to forming the conversion coating on the steel.

Next, the conversion coating method of the present invention will be explained.

(1) Contacting galvanized steel, non-galvanized steel, or a composite of non-galvanized steel and galvanized steel, with or without prior activation, with an aqueous coating solution consisting of the following ingredients and amounts:

Component g/(solution) Zn ⁺⁺ about 0.9-2.5, preferably about 1.5-2.0 ^* Ni ⁺⁺ about 0.6-2.0, preferably about 1.2-1.7 H ₃ PO ₄ (100%) about 15-45, preferably is about 20-35 NO ₃ ^-about 1.0-10.0, preferably 2.0-7.0 NO ₂ ^-** 0.10-0.65, preferably about 0.10-0.40 (*) This concentration range is suitable for non-galvanized steel treatment or non-zinc Used for composite materials of galvanized steel and galvanized steel, or for simultaneous treatment of both. For treatment of galvanized steel only, zinc ions should be approx.
It may range from 0.3 to 2.5, preferably from about 0.9 to 2.5, most preferably from about 1.5 to 2.0.

(**) If the only steel being treated is galvanized steel, nitrite ions may be removed from the coating solution. That is, nitrite ion becomes an optional component. If desired, one or more of the following components can also be added to the aqueous coating solution in the amounts described below.

Optional ingredients g/(solution) ClO ₃ ^-* about 0.4-3.0, preferably 0.8-1.5 Fe ⁺⁺⁺ about 0.010-0.020 Fluoride processed product Small amount (*) Optional but preferred ingredient.

When both nitrate and chlorate ions are present in the aqueous coating solution, it is preferred that the nitrate ions are present in an amount at least twice the amount of chlorate ions.

Following the addition of the above ingredients to the aqueous coating solution, an alkali metal hydroxide, preferably sodium hydroxide or potassium hydroxide, is added to improve the solution.
Adjust the PH to approximately 3.0-3.5 range. When an alkali metal hydroxide is added, sodium phosphate is formed by reaction of the hydroxide with orthophosphoric acid. Of course, similar results can be achieved by separately adding sodium phosphate to the solution and by reducing the amount of orthophosphoric acid added to yield a solution with the required PH. However, this technique is quite cumbersome and unnecessarily expensive.

Divalent zinc ions are provided to the solution by the addition of non-toxic inorganic sources of this ion such as zinc oxide, zinc chloride, zinc nitrate, zinc carbonate, zinc bicarbonate, finely powdered zinc metal, and the like.

Nickel ions are supplied to the solution by non-toxic inorganic sources of the ions such as nickel oxide, nickel chloride, nickel nitrate, nickel carbonate, nickel bicarbonate, finely powdered nickel metal, and the like.

Orthophosphoric acid is available in its usual commercial form, viz.
Preferably, it is added as a 75% aqueous solution.

Nitrate and nitrite ions are preferably added to the solution in the form of their alkali metal salts (eg, sodium or potassium salts). Nitrate ions can also be added as nitric acid.

If chlorate ion is present, it is preferably added to the solution as an alkali metal chlorate (eg, sodium or potassium chlorate).

When adding ferric ions to the solution, the use of ferric chloride is advantageous, but it is also possible to use ferric salts of the anions mentioned above for the addition of zinc ions. Even if ferric ions are not intentionally added to the solution,
It should be recognized that ferric ions are formed in solution during processing of steel.

Fluoride compounds that may be present as optional ingredients may be in the form of fluoride salts or complex fluorides (eg, fluosilicic acid, fluotitanic acid, ammonium difluoride, sodium difluoride, etc.).

The steel to be treated is contacted with the solution by spraying it with the solution or by immersing the steel in the solution.

The solution is maintained at a temperature of about 80-110° (26.7-43.3°C), preferably about 85-95° (29.4-35.0°C). Contact time with steel is at least 30 seconds,
Preferably about 30 seconds to 5 minutes, most preferably about
The duration is 30 seconds to 2 minutes. Since the equilibrium between the coating and the solution is obtained rather quickly, long contact times of 5 minutes or more can be employed without increasing the coating weight, but such long contact times are practically wasteful.

(2) Excess solution is then removed from the coated steel. Excess coating solution is removed from the surface of the coated steel, preferably by rinsing with water. This rinsing step can be carried out at ambient temperature by spraying or dipping the steel in rinsing water. An optional step that may be employed in the method of the invention is a final treatment step following step (2), which comprises coating an acidic aqueous solution containing trivalent chromium ions, hexavalent chromium ions or mixtures of hexavalent/trivalent chromium ions. This can be done by bringing steel into contact. Such solutions and methods for treating coated steel are known in the art and are often employed to treat zinc phosphate coated steel obtained by known methods.

The aqueous composition of the present invention shown in step (1) above differs from conventional low-temperature treatment compositions by containing a high concentration of nickel ions and a low concentration of zinc ions.
Additionally, while many conventional compositions require the presence of manganese, it is neither necessary nor desirable in the composition of the present invention described in step (1) above.

When a clean steel is sprayed into contact with the above solution for one minute, a coating is formed containing about two to three times the amount of divalent nickel ions present in a typical zinc phosphate coating. This result was determined by removing the zinc phosphate film with a solution of chromic acid (5% wt/vol) and analyzing this solution by atomic absorption spectroscopy. Such zinc phosphate coatings were developed using a high resolution (~500 Å) Perkin-Elmer method combining scanning electron microscopy and scanning Augier spectroscopy.
Physical Electronics Division (PHI)
It was also analyzed by Auger electron spectroscopy using a Model 595 Mutiprobe. It was observed that divalent nickel ions were concentrated in the outer 100 Å of the coated surface. When clean steel is contacted by immersion in the solution for 2 minutes, a greater ratio of phosphophyllite (Zn ₂ FeP ₂ O ₈ 4H ₂ O) to hopeite (Zn A film containing _{3P 2} O ₈ 4H ₂ O) was formed. This means that the zinc phosphate film can be replaced with chromic acid (5%wt/
vol) of a solution and analyzing this solution by atomic absorption spectroscopy. Such zinc phosphate coatings were also analyzed by Auger electron spectroscopy to a coating depth of 3000 Å, and this analysis indicated the presence of approximately 11% Fe (relative atomic %). The zinc iron phosphate coatings formed by the novel coating compositions of this invention provide greater corrosion resistance and paint adhesion than conventional zinc phosphate coatings containing only hopeite.

Additionally, the aqueous compositions of the present invention differ from conventional compositions, which tend to form a sludge heavily;
It results in very little sludge formation during use and storage. Additionally, concentrates useful in forming the aqueous treatment compositions of the present invention can be formed, which are quite stable on storage. The concentrates that can be used and which form part of this invention contain each of the above components (except nitrite) in a concentrated aqueous solution. That is, each component is present in greater amounts than in the aqueous composition, for example zinc ion is present at about 2.5 g/m or more. Each component is present in the concentrate in an amount sufficient to provide the required amount of the treated aqueous solution that results upon dilution of the concentrate with a predetermined amount of water. Concentrated liquid is at least about 30
Preferably, it contains zinc ions of g/g/g.
The weight part relationship of the components of the concentrated liquid is as follows, assuming that zinc is 1 for convenience. Ingredients ^* Parts by weight Zn ⁺⁺ 1 Ni ⁺⁺ about 0.24-2.2, preferably about 0.6-1.1 H ₃ PO ₄ (100%) about 6-50, preferably about 10-23.3 NO ₃ ^-about 0.1-11.1, Preferably about 1 to 2.8 (*) Since nitrite is unstable in concentrated solution, it is added separately to the bath. Optional components by weight parts ClO ₃ ^- about 0.16 to 3.3, preferably about 0.4 to 0.6 Fe ⁺⁺⁺ about 0.004 to 0.022, preferably about 0.005 to 0.013 (Note) For formulating coating baths for use only on galvanized steel When preparing a concentrated liquid for use, the weight part relationship of each component is as follows. Ingredient weight parts Zn ⁺⁺ 1 Ni ⁺⁺ about 0.24 to 6.7, preferably about 0.24 to 2.2, more preferably about 0.6 to _{1.1 H2PO4} (100%) about 6 to 150, preferably about 6 to 50, More preferably about 10 to 23.3 _NO3 ^- about 0.4 to 33.3, preferably about 0.4 to 11.1, more preferably about 1 to 2.8 optional parts by weight _ClO3 ^- about 0.16 to 10, preferably about 0.16 to 3.3, more preferably is about 0.4 to 0.6 Fe ⁺⁺⁺ about 0.004 to 0.067, preferably about 0.004 to 0.022, more preferably about 0.005 to 0.013. The methods and compositions of the present invention can be better understood from the following examples; are given for illustrative purposes only and are not meant to limit the invention.

Examples Titanium activated silicate alkaline solution (RIDOLINE 1310, Amchem Produdts, Inc.)
Three cold-rolled steel panels (AISI 1010 low carbon steel alloy) that were cleaned using the same method were processed as follows.

The aqueous coating bath formed contained the following amounts of ingredients:

Coating bath components g/(solution) ZnO 2.25 NiO 1.86 H ₂ PO ₄ (100%) 26.54 NaClO ₃ 1.29 NaNO ₃ 3.96 NaNO ₂ 0.24 FeCl ₃ ·6H ₂ O 0.076 NaOH 4.40 The above aqueous bath was then coated by addition of NaOH. Tsute PH
Adjusted to 3.3. The aqueous baths were formed by adding the following concentrates to a sufficient amount of water to form a 5% aqueous solution of the concentrates, and then adding NaNO ₂ separately to adjust the pH to 3.3.

Concentrated liquid component g/(Concentrated liquid) ZnO 44.96 NiO 37.12 H ₃ PO ₄ (75%) 707.68 NaOH (50% solution) 176.20 NaClO ₃ 25.84 NaNO ₃ 79.20 FeCl ₂・6H ₂ O 1.52 The above concentrated liquid first contains zinc oxide. It was formed by slurrying and nickel oxide in hot water and thoroughly mixing. Phosphoric acid was then slowly added to the stirring mixture until the solution became clear. The solution is then about 100〓
(37.8°C) and slowly added sodium hydroxide solution with stirring. The resulting solution is approximately 120
After cooling to (48.9°C), sodium nitrate, sodium chlorate and ferric chloride hexahydrate were added and the solution was stirred until clear.

The coating bath was then heated to 95°C (35.0°C) and the steel panels were sprayed with the bath for 1 minute to obtain a zinc phosphate coating on the steel substrate.

The steel panels were then rinsed with tap water to remove excess coating solution.

The phosphate-coated steel panels were then PHized by addition of H ₃ PO ₄ (75% solution) containing 0.025% chromium acetate and 0.0008% hydrazine hydrate by volume.
It was treated with an aqueous solution adjusted to 4.0-5.0. The above solution was applied to the steel panel by spraying the panel surface for about 30 seconds.

The steel panels were rinsed with distilled water to remove excess solution. The panels were then air dried and coated with PPG3002
It was immersed in a cationic electrodeposition coating primer bath. Remove the panel from the primer bath and rinse with distilled water to remove excess primer and
Oven baking was performed for 20 minutes at ℃). A DuPont #922 acrylic enamel top coat was then applied using standard electrostatic spray equipment. The panels were then oven baked at 250°C (121.1°C) for 30 minutes. The total film thickness of primer and top coat is
It was 2.1-2.5 mil. After baking, the top coat was smooth, uniform, and highly adhesive. The panels were then subjected to the following tests.

Panel 1 - Salt Spray Test ASTM B-117 Panel 2 - 10 Cycle Surface Scratch (Scab) Test This test uses a 4" horizontal scab starting 4 inches below the top of the panel.
Panels were delineated according to ASTM D-1654.
The drawn panels were then subjected to a 10 cycle test. Each cycle consisted of (a) 24-hour salt spray (ASTM B-117), (b) four 24-hour wet treatments (each treatment typically 8 hours at 100±2°C (37.8±1.1°C) and 100% relative humidity). (16 hours at normal room temperature and relative humidity) and (c) at normal room temperature and relative humidity.
Consists of 48 hours. The panels were then rinsed with water, dried, and tested.

Panel 3 - Wet Adhesion Test This test consists of bonding the panel to deionized water at 50°C for 240°C.
It is carried out by soaking for a period of time. The panel was then removed, air dried and cross-signal tested.
ASTM D-3359 was carried out (however, a 10 crosshatch wire with a width of 2 mm was used in this test). The results of the above test are as follows.

Panel 1 - Salt Spray Test ASTM B-
117 Average damage from crevice after 1500 hours exposure −3/
64" Panel 2 - 10 Cycle Surface Scratch Blister Test Average Damage from Grain Line - 1.4mm Panel 3 - Wet Adhesion Test No Coating Damage After 240 Hours Example Three Cold Rolls of Same Composition as Used in Example Steel panels were treated according to the method of the example except that the phosphate coated steel panels were rinsed with tap water to remove excess coating solution before the following method was applied.

Briefly, phosphate coated steel panels were rinsed with distilled water at room temperature and air dried. The same coating system as in the example was applied to the panel, and the following test was conducted in the same manner as in the example.

Panel 1 - Salt Spray Test ASTM B-
117 Panel 2 - 10 Cycle Surface Scratch Blister Test Panel 3 - Wet Adhesion Test The results obtained are as follows.

Panel 1 - Salt Spray Test ASTM B-
117 Average damage from crevice after 1500 hours of exposure −
1/32" Panel 2 - 10 Cycle Surface Scratch Blister Test Average Damage from Grain Line - 6 mm Panel 3 - Wet Adhesion Test 95% Coating in Crosshatch Area Example Three Cold Rolled Steel Panels (AISI 1010 Low Carbon (steel alloys) were cleaned as shown in the examples.
Rinse the panels with tap water to remove excess cleaner, then soak the panels in a metal activation solution containing 1.2 g of a mixture of the following ingredients per liter of water:
(26.7℃) for 30 seconds. Ingredients Weight % Potassium titanium fluoride 3.5 Disodium phosphate 77.5 Tetrasodium pyrophosphate 19 An aqueous coating bath was formed as shown in the examples and heated to 95°C (35.0°C), and the steel panels were placed in this bath. After immersion for 2 minutes, a smooth zinc phosphate film was obtained on the steel surface.

The steel panels were rinsed with tap water to remove excess coating solution and then with distilled water. The panels were then air dried and the coating system was applied as in the Examples. The test was conducted and the following results were obtained.

Panel 1 - Salt Spray Test ASTM B-
117 Average damage from crevice after 1500 hours exposure −1/
64" Panel 2 - 10 Cycle Surface Scratch Blister Test Average Damage from Grain Line - 1 mm Panel 3 - Wet Adhesion Test No Coating Damage Example The method of the example was carried out on three other cold rolled steel panels of the same composition. Repeat, except that the panels were rinsed with tap water to remove excess coating solution and then processed as follows.

i.e. 200ppm hexavalent chromium and 85ppm trivalent chromium
The panels were immersed for 20 seconds at ambient temperature in an aqueous solution containing: The panels were then removed from the solution, rinsed with distilled water to remove excess solution, and then air dried. The same coating system used in the examples was then applied to the panels in a manner similar to the examples.

The resulting painted panels were smooth, the paint was evenly distributed, and highly adhesive.

The panels were then subjected to the following tests with the following results.

Panel 1 - Salt Spray Test ASTM B-
117 Average damage from crevice after 1500 hours exposure −1/
64" Panel 2 - 10 Cycle Surface Scratch Blister Test Average Damage from Grain Line - 1mm Panel 3 - Wet Adhesion Test No Coating Damage Example Three galvanized steel panels (Armco G90 - Heat Dipped Galvanized Minimum Spangle) with titanium Activated silicate strongly alkaline solution (RIDOLINE
1310, Amchem Products, Inc.).

The panels were then rinsed with tap water and sprayed for 30 seconds at 80°C (26.7°C) with a metal activation solution containing 1.2g of a mixture of the following ingredients per liter of water: Ingredients Weight % Potassium Titanium Fluoride 5 Disodium Phosphate 95 The galvanized steel panels were then sprayed with a coating bath having the following composition at 95°C (35.0°C) for 1 minute.

Coating bath components g/(solution) ZnO 2.25 NiO 1.86 H ₃ PO ₄ (100%) 26.54 NaClO ₃ 1.29 NaNO ₃ 3.96 FeCl ₃・6H ₂ O 0.076 NaOH 4.40 The above bath was adjusted to PH3 by addition of NaOH before use. .3
Adjusted to.

The galvanized steel panels were then rinsed with tap water containing 0.025% chromium acetate and 0.0008% hydrazine hydrate by volume, followed by pH _4.0-5.0 by addition of _H3PO4 (75% solution). An aqueous solution prepared as follows was sprayed for 30 seconds at room temperature.

The galvanized steel panels were rinsed with distilled water to remove excess solution from the panels. The panels were then air dried and the Example coating system was applied according to the Example method.

After drying, the coating film was smooth, uniform, and highly adhesive. The panel was tested with the following results.

Panel 1 - Salt Spray Test ASTM B-
117 67 Average damage from crevice after 2 hours exposure - 5/6
4" Panel 2 - 10 Cycle Surface Scratch Blister Test Average Damage from Scarline - 0.5mm Panel 3 - Wet Adhesion Test 97% Adhesive Coating on Crosshatch Areas Example Three Galvanized Steel Panels (Armco G90 - Heat Dipped Galvanized Minimum Spuggle) was cleaned, treated and painted as in the examples, except that the metal activation solution had 1.2 g of a mixture per liter of water with the following composition: Ingredients wt % nitric acid Manganese 0.01 Potassium Titanium Fluoride 5.00 Disodium Phosphate 94.99 The panel was tested with the following results.

Panel 1 - Salt Spray Test ASTM B-
117 67 Average damage from crevice after 2 hours exposure - 1/1
6″ Panel 2 - 10 cycle surface scratch blister test Average damage from the score line - 0.5mm Panel 3 - Wet adhesion test 99% adhesive coating on crosshatch area Example Cold rolled steel panel (AISI 1010 low carbon steel alloy)
titanium activated silicate strongly alkaline solution (RIDOLINE 1310, Amchem Products, Inc.)
Cleaned using.

The panels were then rinsed with tap water and sprayed for 30 seconds at 80°C (26.7°C) with a metal activation solution containing 1.2g per liter of water of the following composition: Ingredients weight% Potassium titanium fluoride 5 Disodium phosphate 95 Next, apply the coating bath of the example to the steel panel.
(35.0°C) for 1 minute.

The steel panels were then rinsed with tap water and an aqueous solution containing 200 ppm hexavalent chromium and 85 ppm trivalent chromium was sprayed onto the panel surface for 20 seconds at ambient temperature. The panels were then rinsed with distilled water followed by air drying.

A single-coat alkyd paint (Guardsman Tan Single Coat, Guardsman Paint Company), often used in the fabricated metal industry, was sprayed onto the panel surface and then the panel was dried for 12 minutes.
Bake in the oven at 325〓 (162.8℃). Coating thickness was 1.0-1.2 mil. The panels were then tested in the salt spray test ASTM B-117 for 168 hours. Average damage from groin line − 1/32″.

Claims (1)

[Claims] 1 (a) 0.3 to 2.5 g/divalent zinc ion, (b) 0.6 to 2.5 g/divalent zinc ion
2.0g/divalent nickel ion, (c) 15-45g/
of orthophosphoric acid, (d) contains 1.0 to 10.0 g of nitrate ion, and the pH is adjusted to a range of 3.0 to 3.5 by the addition of an alkali metal hydroxide, and the pH is adjusted to 80 to 3.5 by adding an alkali metal hydroxide.
An aqueous composition for treating galvanized steel, characterized in that it is used at a temperature of 110°C (26.7 to 43.3°C). 2. The aqueous composition of item 1 above, further containing 0.4 to 3.0 g/chlorate ion. 3. The aqueous composition according to item 1 or 2 above, further containing 0.010 to 0.020 g/ferric ion. 4. The aqueous composition of item 1 or 2 above, further containing a small amount of a fluoride-containing compound. 5. The aqueous composition of item 1 above, containing 0.9 to 2.5 g/zinc ion. 6. The aqueous composition of item 1 or 2 above, containing 1.5 to 2.0 g/zinc ion. 7. The aqueous composition of item 1 or 2 above, containing 1.2 to 1.7 g/nickel ion. 8. The aqueous composition according to item 1 or 2 above, containing 20 to 35 g/orthophosphoric acid. 9. The aqueous composition according to item 1 or 2 above, containing 2.0 to 7.0 g/nitrate ion. 10 The aqueous composition of item 2 above, containing 0.8 to 1.5 g/chlorate ion. 11. The aqueous composition of item 1 above, containing 1.5 to 2.0 g of zinc ions, 1.2 to 1.7 g of nickel ions, 20 to 35 g of orthophosphoric acid, and 2.0 to 7.0 g of nitrate ions. 12 The aqueous composition of item 11 above, further containing 0.8 to 1.5 g/chlorate ion. 13. The aqueous composition of item 12 above, containing at least twice as much nitrate ion as chlorate ion. 14 (a) 0.9-2.5 g/divalent zinc ion, (b) 0.6
~2.0g/divalent nickel ion, (c)15~45
PH
3.0 to 3.5 by addition of alkali metal hydroxide
The amount of nitrate ions is at least twice the amount of chlorate ions, and the amount of nitrate ions is adjusted to a range of 80 to 110.
An aqueous composition for treating non-galvanized steel or a composite material of non-galvanized steel and galvanized steel, characterized in that it is used at a temperature of (26.7 to 43.3°C). 15 (a) 1.5-2.0 g/divalent zinc ion, (b) 1.2
~1.7g/divalent nickel ion, (c)20~35
g/g/ of orthophosphoric acid, (d) 2.0-7.0 g/nitrate ion, (e) 0.8-1.5 g/chlorate ion, and
(f) Contains 0.10 to 0.40 g of nitrite ion, the pH is adjusted to a range of 3.0 to 3.5 by adding an alkali metal hydroxide, and the amount of nitrate ion is at least the amount of chlorate ion. 2 times, 80~110〓
(26.7-43.3℃)
Aqueous composition of section. 16 A galvanized steel coating method for preparing galvanized steel for top coating, comprising: (a) coating the galvanized steel with 0.3 to 2.5 g/divalent zinc ion and 0.6 to 2.0 g/divalent nickel ion; , 15-45g/orthophosphoric acid, 1.0-
An aqueous solution containing 10.0 g of nitrate ion and whose pH is adjusted to a range of 3.0 to 3.5 by adding an alkali metal hydroxide and an aqueous solution of 80 to 110〓 (26.7 to
(b) removing excess aqueous solution from the surface of the coated galvanized steel. 17. The method of item 16 above, wherein the aqueous solution of (a) further contains 0.4 to 3.0 g/chlorate ion. 18 In the aqueous solution of (a), 0.9~ of zinc ion
2.5g/, nickel ion 1.2-1.7g/, orthophosphoric acid 20-35g/and nitrate ion 2.0-7.0
The method of paragraph 16 above, containing g/g/. 19. The method of item 18 above, wherein the aqueous solution contains 1.5 to 2.0 g/zinc ion. 20. The method of item 19 above, wherein the aqueous solution further contains 0.8 to 1.5 g/chlorate ion. 21. The method of item 20 above, wherein the aqueous solution contains at least twice as much nitrate ion as chlorate ion. 22. The method of item 16 above, wherein the contact time in step (a) is 30 seconds to 2 minutes. 23. The method of item 16 above, wherein the galvanized steel is treated with a titanium-containing metal activation solution. 24 Galvanized steel contains at least 0.005 g/
17. The method of claim 16, wherein the activated aqueous colloid solution contains manganese ions and 0.005 to 0.02 g/g titanium ions. 25 The method of item 24 above, containing 0.025 to 0.075 g/of manganese ion and 0.006 to 0.012 g/of titanium ion. 26. The method of paragraph 25 above, wherein the solution is maintained at a temperature of 60-130°C (15.6-54.4°C) and the treatment time is at least 10 seconds. 27. The method of item 16 above, wherein the coated galvanized steel is further treated with an aqueous solution containing at least one of (a) trivalent chromium ions and (b) hexavalent chromium ions. 28 A method for coating non-galvanized steel or a composite material of non-galvanized steel and galvanized steel for preparing steel for top coating, comprising: (a) coating the above steel with 0.9 to 2.5 g/divalent Zinc ion, 0.6-2.0 g/divalent nickel ion, 15
~45g/orthophosphoric acid, 1.0~10.0g/
of nitrate ion, 0.4-3.0 g/chlorate ion and 0.10-0.65 g/nitrite ion, and the pH is increased by the addition of alkali metal hydroxide.
(b ) A coating method characterized in that excess aqueous solution is removed from the coated surface of the above-mentioned steel. 29 Non-galvanized steel or a composite of non-galvanized steel and galvanized steel is treated with 1.5 to 2.0 g/divalent zinc ions, 1.2 to 1.7 g/divalent nickel ions, 20 to 35 g/orthophosphoric acid, 2.0~7.0g/
Contains nitrate ions, 0.8-1.5g/chlorate ions and 0.10-0.40g/nitrite ions,
PH is increased from 3.0 to 3.0 by adding alkali metal hydroxide
3.5 and in which the amount of nitrate ions is at least twice the amount of chlorate ions, at a temperature of 80 to 110㎓ (26.7 to 43.3 ° C.) for at least 30 seconds. Method. 30. Contacting non-galvanized steel or a composite of non-galvanized steel and galvanized steel with an aqueous solution by spraying it with an aqueous solution to form a film containing a relatively high content of nickel.
Or the method of Section 29. 31. Contacting non-galvanized steel or a composite of non-galvanized steel and galvanized steel with an aqueous solution by immersing it in the aqueous solution to form a film having a relatively high phosphophyllite to hopeite ratio. The method of item 28 or 29. 32 Galvanized steel 80~110〓(26.7~43.3℃)
A concentrated composition for use in formulating an aqueous coating solution for processing at temperatures of 1 to 100 g, comprising: (a) 1 part by weight of divalent zinc ion; (b) 0.24 to 6.7 parts by weight of divalent nickel. (c) 6 to 150 parts by weight of orthophosphoric acid, and (d) 0.4 to 33.3 parts by weight of nitrate ions. Ion concentration 0.3~
2.5g/, Nickel ion concentration 0.6~2.0g/
, a concentrated composition containing each component in sufficient amounts to prepare a solution for treating galvanized steel with an orthophosphoric acid concentration of 15 to 45 g/ and a nitrate ion concentration of 1.0 to 10.0 g. 33 Non-galvanized steel or composite material of non-galvanized steel and galvanized steel 80~110〓(26.7~43.3
A concentrated composition for use in formulating an aqueous coating solution for processing at a temperature of (c) 6 to 50 parts by weight of orthophosphoric acid, and (d) 0.4 to 11.1 parts by weight of nitrate ions. So zinc ion concentration 0.9
~2.5g/, Nickel ion concentration 0.6~2.0g/
, a concentrated composition containing each component in sufficient amounts to prepare a solution with an orthophosphoric acid concentration of 15 to 45 g/and a nitrate ion concentration of 1.0 to 10.0 g/. 34 Chlorate ion concentration 0.4-3.0g/ by dilution
0.16 to 3.3 in sufficient quantities to bring about
34. The concentrated composition of paragraph 33 above, further comprising parts by weight of said ion. 35 Zinc ion concentration 1.5-2.0g/, nickel ion concentration 1.2-1.7g/, orthophosphoric acid concentration 20
~35g/and nitrate ion concentration 2.0~7.0g/
34. The concentrated composition of paragraph 33 above, containing each component in sufficient amounts to prepare a solution of the composition. 36. The concentrated composition of paragraph 35 above, further comprising chlorate ions in an amount sufficient to prepare a solution containing 0.8 to 1.5 g/h of chlorate ions. 37. The concentrated composition of item 33 above, containing 0.004 to 0.022 parts by weight of ferric ions per 1 part by weight of divalent zinc ions. 38. The concentrated composition of item 33, 34, 35, 36 or 37 above, containing at least 30 g/zinc ion.