JP2000054157A - Hexavalent chromium and fluorine-free chemical treating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hexavalent chromium and fluoride-free chemical surface treating agent for zinc or zinc alloy plating forming a chemical coating excellent in corrosion resistance by using trivalent chromium ions, phosphorus and molyb denum or the like. SOLUTION: The chemical surface treating agent contains one or more selected from among Mo, Ni, W, Co, Ti, Mg, Ca, Mn and Ba, phosphorus and trivalent Cr ions. A zinc or zinc alloy plated article is chemically treated with the treating agent under the conditions of a pH of 1.0-4.0, a temp. of 10-60 deg.C, a time of 5-18 sec, a conc. of 0.4-10 g/l [expressed in terms of chromium (III)] trivalent chromium compd., 0.2-10 g/l (expressed in terms of phosphorus) phosphorus compd. and 0.1-4 g/l (expressed in terms of Mo) Mo compd., 0.1-10 g/l (expressed in terms of Ni) Ni compd., 0.1-5 g/l (expressed in terms of W) W compd., 0.1-5 g/l (expressed in terms of Co) Co compd. or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hexavalent chromium / fluorine-free chemical conversion treatment, and more particularly to a hexavalent chromium / fluorine-free chemical conversion treatment used in a chemical conversion treatment after plating zinc or a zinc alloy.

[0002]

2. Description of the Related Art Conventionally, zinc plating has been used relatively frequently as a method of preventing corrosion of a metal surface. However, in order to further improve the corrosion resistance of a plated surface, a chromate treatment is generally performed after zinc plating. It is a target. This chromate film further improves the corrosion resistance. Conventionally, gloss chromate treatment has been used as chromate treatment. Recently, however, colored chromate treatment such as black chromate treatment in terms of appearance and green chromate treatment in terms of corrosion resistance has been used relatively frequently.

[0003] As described above, the chromate treatment widely used today consists of a basic bath composed of chromic anhydride and mineral acid (H ₂ S).
O _4, HNO _3, HF, an aqueous solution of containing _{H 2 SiF 6, H 3 PO} 4, HCl), typically are classified into a coating type reactive with the electrolytic, 6 in anhydrous chromic acid-containing solution The film is formed by converting trivalent chromium into trivalent chromium. For example, the coating composition of this _{time, xCr 2 O 3 · yCrO 3} · zH 2 O , and the coating type, reaction type, in any of the electrolytic also residual hexavalent chromium unreduced Some generation film Is inevitable.

As described above, the purpose of the chromate treatment for zinc is chemical polishing and chemical conversion film formation. For the former chemical polishing, a fluorine compound is added, and for the film formation, hexavalent chromium is used. We are dealing with reduction.

However, since the hexavalent chromium is contained in the chromate-treated film in recent years, there is a fear that the hexavalent chromium may have an adverse effect on the human skin.
The problem is that chromium (valent) elutes from the coating and remains in nature.

For example, Japanese Unexamined Patent Publication (Kokai) No. 7-126859 discloses a chemical conversion treatment agent free of hexavalent chromium, but requires the use of a fluorine compound as described above. As described above, various processing methods have been studied to solve this problem, but no sufficient solution has been found yet.

[0007]

Accordingly, one object of the present invention is to develop a technique for solving the problem of elution of hexavalent chromium remaining in a chromate film.

At present, a treatment method using trivalent chromium, in which only the trivalent chromium is contained in the chromate treatment solution from the beginning, is promising, but the reduction from hexavalent chromium to trivalent chromium is promising. From the beginning, it has been found that the method using trivalent chromium does not form a sufficient film and the corrosion resistance is considerably inferior to the conventional method in which the film formation is promoted.

Therefore, another object of the present invention is to develop a technique for forming a chemical conversion film having excellent corrosion resistance by a surface treatment using a treatment solution containing no hexavalent chromium. In addition, as described above, the chromate treatment solution may contain a fluorine compound, which is effective for chemical polishing of the surface of the article to be treated, and in order to obtain excellent film adhesion and corrosion resistance, The use of fluoride is desirable. But,
It is not preferable to use fluoride because it has a bad effect on human bones.

[0010] Therefore, still another object of the present invention is to provide:
It is an object of the present invention to develop a technology for forming a chemical conversion coating film having more excellent corrosion resistance by a chemical conversion treatment using a surface treatment solution that does not use hexavalent chromium / fluoride.

[0011]

Means for Solving the Problems The present inventors applied a conventional chemical treatment with a solution containing trivalent chromium, molybdic acid and phosphoric acid to a conventional chromate film without sticking to the conventional chromate treatment. Knowing that a comparable chemical conversion coating was formed, the present invention was completed.

It has also been found that the same effect can be obtained by using nickel, tungsten, cobalt, titanium, magnesium, calcium, manganese and barium sulfates instead of molybdic acid.

Here, the present invention is as follows. (1) Molybdenum, nickel, tungsten, cobalt,
It contains one or more members selected from the group consisting of titanium, magnesium, calcium, manganese and barium, phosphorus and trivalent chromium ions, and contains hexavalent chromium.
Hexavalent chromium / fluorine-free chemical conversion surface treatment agent for zinc or zinc alloy plating characterized by not containing fluoride. (2) A method for preventing corrosion of a galvanized film, characterized by further applying another type of coating treatment to the film obtained by treating with the chemical conversion surface treatment agent of the above (1).

[0014]

Next, the present invention will be described more specifically with reference to the accompanying drawings. FIG. 1 is a process diagram in the case where the present invention is applied to a galvanized or zinc alloy-plated article. First, an article targeted in the present invention is subjected to a plating treatment of a so-called secondary molded product in advance. And zinc-plated or zinc-alloy-plated articles, for example, automobile parts, home electric parts and the like. After such an article is washed with water, the article is generally immersed in a nitric acid solution, if necessary, a sulfuric acid or hydrochloric acid solution, subjected to an acid activation treatment, and washed with water.

As described above, the chemical conversion treatment is performed using the chemical conversion treatment agent according to the present invention after the acid activation treatment, and the composition of the chemical conversion treatment agent and the conditions of the chemical conversion treatment are as follows.

Range of composition of chemical conversion treatment agent and treatment conditions pH range: 1.0 to 4.0, preferably 1.5 to 2.5 Temperature range: 10 to 60 ° C, preferably 50 ° C or less, more preferably 20 to 30 ° C Time range : 5 to 180 seconds, preferably 30 to 90 seconds Trivalent chromium compound: 0.4 to 10 g / l as chromium (III)
Preferably 1 to 8 g / l phosphorus compound: 0.2 to 10 g / l as phosphorus, preferably 0.5 to 10 g / l, more preferably 1 to 5 g / l molybdenum compound: 0.1 to 4 g / l as molybdenum
Preferably, 0.5 to 2 g / l Nickel compound: 0.1 to 10 g / l as nickel Tungsten compound: 0.1 to 5 g / l as tungsten Cobalt compound: 0.1 to 5 g / l as cobalt Titanium compound: 0.1 to 10 g / l as titanium Magnesium compound: 0.1 to 10 g / l as magnesium Calcium compound: 0.1 to 10 g / l as calcium Manganese compound: 0.1 to 10 g / l as manganese Barium compound: 0.1 to 10 g / l as barium In addition, for example, ammonium nitrate is appropriately used as a pH adjuster It may be added in an amount.

Here, the metal compounds such as trivalent chromium compound and molybdenum compound used in the present invention and the phosphorus compound are those which supply metal ions such as trivalent chromium ion, phosphorus ion and molybdenum in an aqueous solution. Although there is no particular limitation, specific examples thereof are as follows. Of course, these are only examples, and are not intended to limit the invention.

Trivalent chromium compounds: chromium (III) sulfate, chromium (III) acetate, chromium (III) nitrate, chromium (II) chloride
I), chromium (III) biphosphate Phosphorus compounds: ammonium phosphate (ammonium monophosphate, diammonium phosphate, tertiary ammonium phosphate), sodium phosphate (monosodium monophosphate, secondary
Sodium phosphate, tribasic sodium phosphate), potassium phosphate (monobasic potassium phosphate, dibasic potassium phosphate, tribasic potassium phosphate), phosphoric acid, sodium pyrophosphate,
Potassium pyrophosphate, sodium tripolyphosphate, potassium tripolyphosphate, sodium hexametaphosphate Molybdenum compound: ammonium molybdate, sodium molybdate, potassium molybdate Nickel compound: nickel nitrate, nickel sulfate, nickel chloride Tungsten compound: ammonium tungstate, sodium tungstate , Potassium tungstate Cobalt compound: cobalt nitrate, cobalt sulfate, cobalt chloride Titanium compound: sodium titanate, titanium chloride, titanium sulfate Magnesium compound: magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium biphosphate Calcium compound: calcium nitrate, sulfuric acid calcium,
Calcium chloride, slaked lime Manganese compound: manganese sulfate, manganese chloride, potassium permanganate Barium compound: barium nitrate After chemical conversion treatment, wash once with water and then dry.

In the above steps, the acid activity and drying steps may be omitted. By such a chemical conversion treatment, a chemical conversion coating containing a metal component such as molybdenum is formed on the surface of the article, but depending on the application, corrosion resistance may be insufficient, and at that time, a coating treatment of an organic resin film is further performed. You may.

FIG. 2 shows a process chart for performing the coating process. After the above-mentioned chemical conversion film is formed, washing and drying are performed, but this drying may be omitted. Then, it is appropriately immersed in a bath of a coating agent. Examples of the coating agent at this time include water-soluble or water-dispersible resins such as acrylic, urethane, silicone, and melamine. After coating is completed, the product is dried.

Thus, according to the present invention, by using a metal compound such as a trivalent chromium compound and a molybdenum compound and a phosphorus compound together, a hexavalent chromium-free composite film of trivalent chromium-each metal-phosphorus is formed. Thus, the corrosion resistance can be improved without using fluoride.

The external appearance of the treatment can be freely adjusted from unichrome (light blue) to yellow depending on the reaction time and temperature conditions.

Although the above-mentioned Japanese Patent Application Laid-Open No. Hei 7-1226859 suggests the possibility of containing molybdenum, molybdenum at that time is treated as an equivalent of zirconium, and phosphorus-molybdenum when fluorine is free. No specific mention is made of the metal-chromium (III) coexistence effect.

The above-mentioned metal used in the present invention includes:
One or more selected from the group consisting of Mo, Ni, W, Co, Ti, Mg, Ca, Mn and Ba, and when further classified, at least one of the following (1) to (4) There is only one, and the preferred combination from the viewpoint of the effects is (1) → (4). (1) at least one of tungsten, cobalt and magnesium (2) nickel and / or calcium (3) at least one of molybdenum, titanium and manganese (4) barium

[0025]

[Example 1] Galvanizing steel bolts (8 µm)
After rinsing with water, the plate was immersed in an acid active solution of 67.5% nitric acid (2 mL / L) at room temperature for 5 seconds and then washed with water. Then, at 25 ° C in the following formulation aqueous solution
Shake for 60 seconds or immerse in air agitation, wash at 60 ° C
Dried for 15 minutes.

Trivalent chromium compound, molybdenum compound,
Compound treatment liquid Chromium (III) sulfate ・ Hydrate: 30 g / L Ammonium nitrate: 10 g / L Ammonium molybdate tetrahydrate: 5 g / L Ammonium monophosphate: 15 g / L Water: Remaining [Comparative Example 1] ] A steel bolt was zinc-plated (8 μm), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds, and washed with water. After that, it was immersed in a hexavalent chromium-containing chromate agent: Metas CY-33 (10 mL / L) manufactured by Yuken Industry Co., Ltd. at 25 ° C. for 15 seconds with shaking or air stirring, washed with water and dried at 60 ° C. for 15 minutes.

Comparative Example 2 Galvanized steel bolts (8 μm)
m) and washed with water, immersed in 67.5% nitric acid (2 mL / L) at room temperature for 5 seconds, and washed with water. Then, add 25
Shaking for 60 seconds or immersion in air agitation.
For 15 minutes.

Trivalent chromium compound treatment solution Chromium (III) sulfate ・ Hydrate: 30 g / L Ammonium nitrate: 10 g / L Water: Remaining [Comparative Example 3] Galvanizing steel bolts (8 μm) and washing with water And 67.5% nitric acid at room temperature for 5 seconds in 2 mL / L of an acid activation solution, followed by washing with water. Then, it was immersed in the following mixed aqueous solution at 50 ° C. for 30 seconds, washed with water and dried at 80 ° C. for 30 seconds.

Trivalent chromium compound / titanium compound, phosphide
Compound / fluoride treatment liquid Orthophosphoric acid: 1.0 g / L Chromium (III) nitrate: 1.2 g / L Titanium hydrofluoric acid: 1.1 g / L Borofluoric acid: 0.5 g / L Hydrogen peroxide: 0.2 g / L L water: remaining [Comparative Example 4] A steel bolt was zinc-plated (8 µm), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds, and washed with water. Then, it was immersed in the following compounded aqueous solution at 40 ° C. for 20 seconds, washed with water and dried at 50 ° C. for 2 minutes.

Trivalent chromium compound / zirconium compound,
Treatment solution of phosphorus compounds and fluorides Chromium (III) diphosphate: 5.0 g / L Zirconium hydrofluoric acid: 4.0 g / L Hydrofluoric acid: 0.5 g / L Water: Remaining

[0031]

[Table 1]

As can be seen from the results shown in Table 1, according to the present invention, it is understood that a chemical conversion film having the same corrosion resistance as the film obtained by the conventional clotting treatment (Comparative Example 1) is formed. On the other hand, the chromium compound alone (Comparative Example 2), the phosphoric acid containing a fluorine compound (Comparative Example 3) and the fluorine compound containing a zirconium compound (Comparative Example 4) all have insufficient corrosion resistance. You can see that.

Example 2 A steel bolt was zinc-iron alloy plated (8 μm, iron eutectoid rate 0.4%), washed with water, and immersed in a 67.5% nitric acid 2 mL / L acid-activated solution at room temperature for 5 seconds. After washing with water. Thereafter, the mixture was shaken or immersed in air with stirring at 25 ° C. for 60 seconds, washed with water, and dried at 60 ° C. for 15 minutes.

Trivalent chromium compound, molybdenum compound, lithium
Compound treatment liquid Chromium (III) sulfate ・ Hydrate: 30 g / L Ammonium nitrate: 10 g / L Ammonium molybdate ・ tetrahydrate: 15 g / L Ammonium monophosphate: 30 g / L Water: Remaining [Comparative Example 5] ] A steel bolt was plated with zinc-iron alloy (8 µm, iron eutectoid ratio 0.4%), washed with water, immersed in a 67.5% nitric acid 2mL / L acid activated solution at room temperature for 5 seconds, and washed with water. Then, a chromate agent containing hexavalent chromium manufactured by Yuken Industries Co., Ltd .: Metas CY-33 (1
(0 mL / L) at 25 ° C. for 15 seconds with rocking or air stirring and immersion, washed with water and dried at 60 ° C. for 15 minutes.

Comparative Example 6 A steel bolt was zinc-iron alloy plated (8 μm, iron eutectoid rate 0.4%), washed with water, and immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds. After washing with water. Thereafter, the mixture was shaken or immersed in air with stirring at 25 ° C. for 60 seconds, washed with water, and dried at 60 ° C. for 15 minutes.

Trivalent chromium compound treatment liquid Chromium (III) sulfate ・ Hydrate: 30 g / L Ammonium nitrate: 10 g / L Water: Remaining [Comparative Example 7] Zinc-iron alloy plating on steel bolts (8 μm, iron eutectoid) After washing with water at a rate of 0.4%), the plate was immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds and then washed with water. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds,
After washing with water, it was dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / titanium compound, phosphidized
Compound / fluoride treatment liquid Orthophosphoric acid: 1.0 g / L Chromium (III) nitrate: 1.2 g / L Titanium hydrofluoric acid: 1.1 g / L Borofluoric acid: 0.5 g / L Hydrogen peroxide: 0.2 g / L L water: remaining [Comparative Example 8] A steel bolt was zinc-iron alloy plated (8 µm, iron eutectoid rate 0.4%), washed with water, and then treated with an acid active solution of 67.5% nitric acid 2mL / L at room temperature for 5 seconds. After immersion, it was washed with water. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds,
After washing with water, it was dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / zirconium compound,
Treatment solution of phosphorus compounds and fluorides Chromium (III) diphosphate: 5.0 g / L Zirconium hydrofluoric acid: 4.0 g / L Hydrofluoric acid: 0.5 g / L Water: Remaining

[0039]

[Table 2]

In the case of the above-mentioned zinc alloy plating, similarly to the case of the zinc plating, according to the present invention, it is understood that a chemical conversion film having the same corrosion resistance as the conventional chromate treatment is formed.

Example 3 Galvanized steel bolts (8 μm)
m) and washed with water, immersed in a 67.5% nitric acid 2 mL / L acid activation solution at room temperature for 5 seconds, and then washed with water. Then, at 25 ℃
For 60 seconds or dipped in air with stirring, washed with water and dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / nickel compound / phosphorus compound treatment liquid chromium (III) sulfate / hydrate: 30 g / L 67.5% nitric acid: 3 g / L nickel nitrate / hexahydrate: 3 g / L primary phosphoric acid Potassium: 20 g / L Water: Remaining [Example 4] A steel bolt is zinc-iron alloy plated (8 μm, iron eutectoid rate 0.4%), washed with water, and then treated with an acid active solution of 67.5% nitric acid 2mL / L. After immersion at room temperature for 5 seconds, it was washed with water. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds in the following aqueous solution,
After washing with water, it was dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / nickel compound / phosphorus compound treatment solution chromium (III) sulfate / hydrate: 30 g / L 67.5% nitric acid: 3 g / L nickel nitrate / hexahydrate: 3 g / L primary phosphoric acid Potassium: 20 g / L Water: Remaining Example 5 A steel bolt was zinc-plated (8 μm), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds, and washed with water. Thereafter, the mixture was shaken or immersed in air with stirring at 25 ° C. for 60 seconds, washed with water, and dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / tungsten compound
Phosphorus compound treatment liquid Chromium (III) nitrate-Hydrate: 30 g / L Sodium nitrate: 10 g / L Sodium tungstate-Dihydrate: 2 g / L 75% phosphoric acid: 30 g / L Water: Remaining [Example 6] ] A steel bolt was plated with zinc-iron alloy (8 µm, iron eutectoid ratio 0.4%), washed with water, immersed in a 67.5% nitric acid 2mL / L acid activated solution at room temperature for 5 seconds, and washed with water. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds in the following aqueous solution,
After washing with water, it was dried at 60 ° C. for 15 minutes.

Trivalent chromium compounds, tungsten compounds,
Phosphorus compound treatment liquid Chromium (III) nitrate ・ Hydrate: 30 g / L Sodium nitrate: 10 g / L Sodium tungstate ・ Dihydrate: 2 g / L 75% phosphoric acid: 30 g / L Water: Remaining [Example 7] ] A steel bolt was zinc-plated (8 µm), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds, and washed with water. Thereafter, the mixture was shaken or immersed in air with stirring at 25 ° C. for 60 seconds, washed with water, and dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / cobalt compound / phosphorus compound treatment liquid chromium (III) sulfate / hydrate: 30 g / L sodium nitrate: 10 g / L cobalt nitrate / hexahydrate: 2 g / L 75% phosphoric acid: Example 8: A steel bolt is zinc-iron alloy plated (8 μm, iron eutectoid rate 0.4%), washed with water, and then treated with an acid active solution of 67.5% nitric acid 2mL / L at room temperature. After immersion for 5 seconds, it was washed with water. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds in the following aqueous solution,
After washing with water, it was dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / cobalt compound / phosphorus compound treatment solution Chromium (III) sulfate / hydrate: 30 g / L sodium nitrate: 10 g / L cobalt nitrate / hexahydrate: 2 g / L 75% phosphoric acid: Example 9 A steel bolt was zinc-plated (8 μm), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds, and washed with water. Thereafter, the mixture was shaken or immersed in air with stirring at 25 ° C. for 60 seconds, washed with water, and dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / titanium compound / phosphorus compound treatment liquid chromium (III) nitrate hydrate: 30 g / L 67.5% nitric acid: 3 g / L sodium titanate: 3 g / L sodium tripolyphosphate: 20 g / L water : Remaining [Example 10] A steel bolt is zinc-iron alloy plated (8 µm, iron eutectoid rate 0.4%), washed with water, and immersed in a 67.5% nitric acid 2mL / L acid active solution at room temperature for 5 seconds. Washed with water. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds in the following aqueous solution,
After washing with water, it was dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / titanium compound / phosphorus compound treatment liquid chromium (III) nitrate / hydrate: 30 g / L 67.5% nitric acid: 3 g / L sodium titanate: 3 g / L sodium tripolyphosphate: 20 g / L water Example 11: A steel bolt was zinc-plated (8 μm), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds, and washed with water. Thereafter, the mixture was shaken or immersed in air with stirring at 25 ° C. for 60 seconds, washed with water, and dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / magnesium compound
Phosphorus compound treatment liquid Chromium (III) sulfate ・ Hydrate: 30 g / L Sodium nitrate: 10 g / L Magnesium sulfate ・ heptahydrate: 5 g / L 75% phosphoric acid: 30 g / L Water: Remaining [Example 12] Steel bolts were plated with zinc-iron alloy (8 μm, iron eutectoid rate 0.4%), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid activated solution at room temperature for 5 seconds, and washed with water. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds in the following aqueous solution,
After washing with water, it was dried at 60 ° C. for 15 minutes.

Trivalent chromium compounds / magnesium compounds
Phosphorus compound treatment liquid Chromium (III) sulfate ・ Hydrate: 30 g / L Sodium nitrate: 10 g / L Magnesium sulfate ・ heptahydrate: 5 g / L 75% phosphoric acid: 30 g / L Water: Remaining [Example 13] The steel bolt was zinc-plated (8 μm), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds, and washed with water. Thereafter, the mixture was shaken or immersed in air with stirring at 25 ° C. for 60 seconds, washed with water, and dried at 60 ° C. for 15 minutes.

[0052] Trivalent chromium compounds, calcium compounds,
Compound treatment liquid Chromium (III) sulfate ・ Hydrate: 30 g / L 67.5% nitric acid: 3 g / L Calcium chloride: 5 g / L Tertiary sodium phosphate: 20 g / L Water: Remaining [Example 14] Steel bolt The resultant was subjected to zinc-iron alloy plating (8 μm, iron eutectoid ratio 0.4%), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds, and washed with water. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds in the following aqueous solution,
After washing with water, it was dried at 60 ° C. for 15 minutes.

[0053] Trivalent chromium compound, calcium compound,
Compound treatment liquid Chromium (III) sulfate ・ Hydrate: 30 g / L 67.5% nitric acid: 3 g / L Calcium chloride: 5 g / L Tribasic sodium phosphate: 20 g / L Water: Remaining [Example 15] The bolts were zinc-plated (8 μm), washed with water, immersed in 67.5% nitric acid (2 mL / L) at room temperature for 5 seconds, and washed with water. Thereafter, the mixture was shaken or immersed in air with stirring at 25 ° C. for 60 seconds, washed with water, and dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / manganese compound / phosphorus compound treatment liquid Chromium (III) chloride / hydrate: 30 g / L sodium nitrate: 10 g / L manganese sulfate / heptahydrate: 5 g / L 75% phosphoric acid: 30 g / L water: remaining [Example 16] A steel bolt was zinc-iron alloy plated (8 μm, iron eutectoid rate 0.4%), washed with water, and then treated with 67.5% nitric acid 2 mL / L acid activated solution at room temperature. After immersion for 5 seconds, it was washed with water. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds in the following aqueous solution,
After washing with water, it was dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / manganese compound / phosphorus compound treatment liquid chromium (III) chloride / hydrate: 30 g / L sodium nitrate: 10 g / L manganese sulfate / heptahydrate: 5 g / L 75% phosphoric acid: 30 g / L water: remaining [Example 17] A steel bolt was zinc-plated (8 μm), washed with water, immersed in a 67.5% nitric acid 2 mL / L acid active solution at room temperature for 5 seconds, and washed with water. Thereafter, the mixture was shaken or immersed in air with stirring at 25 ° C. for 60 seconds, washed with water, and dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / barium compound / phosphorus compound treatment liquid chromium (III) nitrate hydrate: 30 g / L sodium nitrate: 10 g / L barium nitrate: 5 g / L 75% phosphoric acid: 30 g / L water: [Example 18] Zinc-iron alloy plating (8 µm, iron eutectoid rate 0.4%) on steel bolts, water washing, immersion in 67.5% nitric acid 2mL / L acid active solution at room temperature for 5 seconds, and water washing did. After that, it is shaken or immersed in air with stirring at 25 ° C for 60 seconds in the following aqueous solution,
After washing with water, it was dried at 60 ° C. for 15 minutes.

Trivalent chromium compound / barium compound / phosphorus compound treatment solution chromium (III) nitrate hydrate: 30 g / L sodium nitrate: 10 g / L barium nitrate: 5 g / L 75% phosphoric acid: 30 g / L water: Remaining These results are summarized in Table 3.

[0058]

[Table 3]

[0059]

As described above, according to the present invention, by treating with a chemical conversion treatment solution that does not contain hexavalent chromium and fluorine, it is possible to obtain an excellent or better chromate film. A film exhibiting excellent corrosion resistance can be obtained, and it can easily cope with environmental problems and health problems that are a problem today, and its practical significance is great.

[Brief description of the drawings]

FIG. 1 is a process chart of one embodiment when a chemical conversion treating agent according to the present invention is used.

FIG. 2 is a process chart of another embodiment when the chemical conversion treating agent according to the present invention is used.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuhiro Hayashi 50 Nobacho, Noda-cho, Kariya-shi, Aichi F-term in Yuken Industry Co., Ltd. (reference) 4K026 AA02 AA07 AA21 BA12 BB01 BB08 CA13 CA18 CA19 CA23 CA24 CA25 CA29 CA31 CA32 CA33 CA36 DA12 EB08

Claims (2)

[Claims] 1. Molybdenum, nickel, tungsten,
Containing one or more selected from the group consisting of cobalt, titanium, magnesium, calcium, manganese and barium, phosphorus and trivalent chromium ions, and
Hexavalent chromium / fluorine-free chemical conversion surface treatment agent for zinc or zinc alloy plating characterized by not containing valent chromium / fluoride. 2. A method for preventing corrosion of a galvanized film, characterized by further applying another type of coating treatment to the film obtained by treating with the chemical conversion surface treating agent according to claim 1.