KR20000029286A - A process treatment of metallic materials and treatment solution - Google Patents

Abstract

PURPOSE: A non-chromate type composition is provided to have conductive film adhesion and corrosion resistance on the surface of metal such as aluminum, magnesium and zinc. CONSTITUTION: A composition is composed of at least one kind of metal acetylacetonate selected from a group comprised of Al(C5H7O2)3, V(C5H7O2)3, VO(C5H7O2)2, Zn(C5H7O2)2, and Zr(C5H7O2)4 and at least one kind of a compound selected from a soluble mineral titanium compound and a soluble mineral zirconium compound at a weight rate of 1: 5000 to 5000: 1. A surface processing solution contains 0.01 to 50g/L of at least one kind of metal acetylacetonate selected from Al(C5H7O2)3, V(C5H7O2)3, Zn(C5H7O2)2, and Zr(C5H7O2)4, 0.01 to 50g/L of at least one kind of a compound selected from the soluble mineral titanium compound and the soluble mineral zirconium compound, and also 2.0 to 7.0 of pH.

Description

Metal surface treatment composition, surface treatment liquid and surface treatment method {A PROCESS TREATMENT OF METALLIC MATERIALS AND TREATMENT SOLUTION}

The present invention relates to a novel metal surface treatment composition, a surface treatment liquid and a surface treatment method for imparting excellent corrosion resistance and coating film adhesion to surfaces of various metals such as aluminum, aluminum alloys, magnesium, magnesium alloys and galvanized steel sheets. .

Generally, the surface treatment liquid for aluminum or an aluminum alloy material can be roughly divided into a chromate type and a non-chromate type. As typical examples of the treatment solution of the chromate type, there may be mentioned chromic acid chromate chemical treatment liquid and phosphoric acid chromate chemical treatment liquid.

First, the chromic acid chromate conversion treatment liquid is demonstrated.

Chromic acid chromate chemical treatment solution was put to practical use around 1950 and is still widely used for surface treatment of automotive heat exchangers, aluminum wheels, building materials and aircraft materials. This chromic acid chromate conversion treatment liquid contains chromic acid and a fluoride as a reaction accelerator as a main component to form a chemical conversion film containing some hexavalent chromium on the metal material surface.

In addition, the chromate phosphate chemical treatment solution according to the invention disclosed in U.S. Patent No. 2438877, which contains a chromic acid, phosphoric acid and hydrofluoric acid as main components, and a chemical film containing chromic phosphate as a main component on the surface of the metal material. Form. Since this chemical conversion film does not contain hexavalent chromium, it is widely used for the non-coating treatment of the body material and lid material of beverage cans.

Although the chemical conversion film formed by the chromate-type surface treatment liquid has excellent corrosion resistance and coating film adhesion, it contains harmful hexavalent chromium in the treatment liquid. Therefore, due to environmental problems, the treatment solution containing no hexavalent chromium is used. This is desired.

As a typical invention of the surface treatment liquid of the non-chromate type which does not contain chromium, the process liquid disclosed by Unexamined-Japanese-Patent No. 52-131937 is mentioned. This surface treatment solution is an acidic aqueous coating solution containing zirconium or titanium or a mixture thereof, phosphate and fluoride, and having a pH of about 1.5 to 4.0. When the surface of the metal material is treated using this surface treatment liquid, a chemical conversion film mainly containing zirconium or titanium oxide is formed on the metal surface.

This non-chromate type surface treatment liquid has the advantage that it does not contain hexavalent chromium, and is currently widely used for surface treatment of aluminum DI cans, but has the disadvantage that the corrosion resistance of the formed film is worse than that of the chromate film.

As a non-chromate type process liquid, what was disclosed by the following patent publication is mentioned further.

For example, the treatment method disclosed in Japanese Patent Application Laid-Open No. 57-41376 discloses one or two or more kinds of titanium salts or zirconium salts and one or two or more kinds of imidazole derivatives on the surfaces of aluminum, magnesium, and alloys thereof, and nitric acid. Surface treatment is carried out using an aqueous solution containing an oxidizing agent such as hydrogen peroxide, potassium permanganate, and the like. The corrosion resistance of the coating formed by this treatment solution was sufficient 15 years ago but is not satisfactory at present.

Japanese Laid-Open Patent Publication No. 56-136978 discloses a chemical conversion treatment liquid comprising a vanadium compound and an aqueous solution containing at least one compound selected from the group consisting of titanium salts, zirconium salts and zinc salts. However, in the chemical conversion film formed by this treatment liquid, when long-term corrosion resistance test is performed, it is impossible to expect corrosion resistance more than the chromate coating.

As mentioned above, when the conventional non-chromate type surface treatment liquid is used, the subject remains in the corrosion resistance of the formed chemical film especially. Therefore, in the surface treatment line, such as an aluminum alloy heat exchanger, an aluminum-type metal material coil, and sheet | seat material which requires especially excellent corrosion resistance, the non-chromate type surface treatment liquid is hardly used at present.

Therefore, at present, no surface treatment liquid for aluminum or aluminum alloy material capable of forming a chemical coating which is excellent in wastewater treatment properties without containing hexavalent chromium in the treatment liquid and excellent in corrosion resistance and coating film adhesion is not established.

Next, the surface treatment liquid and the surface treatment method for magnesium or a magnesium alloy are demonstrated.

As a surface treatment method for magnesium or a magnesium alloy material, chromate treatment represented by JIS-H-8651, MIL-M-3171, etc. is put to practical use. The chemical conversion film formed by the chromate-type surface treatment liquid contains extremely hexavalent chromium in the treatment liquid although it has excellent corrosion resistance and coating film adhesion. Therefore, the treatment solution containing no hexavalent chromium due to environmental problems is used. This is desired.

As a typical invention of the surface treatment liquid of the non-chromate type which does not contain chromium, the method disclosed by Unexamined-Japanese-Patent No. 3-6994 is mentioned. This treatment method is to perform silicate treatment after phosphate treatment and silicon treatment on it again. In the phosphate treatment alone coating, there is a problem that the level of corrosion resistance and coating adhesion is low as a method of uncoated treatment of the surface of magnesium or magnesium alloy material. . Moreover, this treatment method requires drawbacks such as a multistage treatment process, a high treatment temperature, and a long treatment time.

As a surface treatment method using phosphate, a method using a treatment solution such as zinc phosphate, iron phosphate, calcium phosphate or zirconium phosphate is known, but these methods are difficult to impart sufficient corrosion resistance in practical use.

For example, seven kinds of JIS-H-8651 disclose manganese phosphate treatment, which contains chromium, which has a high treatment temperature of 80 to 90 ° C. and a long treatment time of 30 to 60 minutes, which is practically unsatisfactory. It is.

The following publications are mentioned as a technique of a non-chromate type.

Japanese Patent Laid-Open No. 9-228062 discloses at least one organometallic compound selected from metal alkoxides, metal acetylacetonates, metal carboxylates, acids, alkalis, salts thereof, hydroxyl groups, carboxyl groups, and amino groups. A surface treatment method is disclosed in which an aqueous solution containing at least one film forming aid or film forming stabilizer selected from an organic compound having any one of the above is applied to a magnesium material at a temperature of 0 to 50 ° C. However, in the chemical conversion film formed by this treatment liquid, corrosion resistance equal to or higher than that of the chromate coating cannot be expected when a long-term corrosion resistance test is performed.

As described above, when the non-chromate type surface treatment solution conventionally proposed for magnesium or magnesium alloy is used, the formed chemical film has high corrosion resistance and treatment temperature, long treatment time, high treatment concentration and low corrosion resistance. The problem remains in practical treatment conditions such as the like. Therefore, in the surface treatment line of the magnesium alloy automobile material, aircraft material, electronic device material, and communication device material which require excellent corrosion resistance and coating film adhesiveness, the non-chromate type surface treatment liquid is hardly used at present.

Therefore, at present, no surface treatment liquid for magnesium or magnesium alloy material capable of forming a chemical coating which does not contain hexavalent chromium in the treatment liquid and has excellent workability and excellent corrosion resistance and coating film adhesion is not established.

Next, the surface treatment of a galvanized material is demonstrated.

As a treatment method for galvanizing materials, chromate treatment or zinc phosphate treatment is generally used. In the chromate treatment, excellent film performance is obtained, but harmful chromium is contained in the treatment liquid, which is a problem in operation and disposal. And zinc phosphate treatment may not get sufficient corrosion resistance.

As a technique of the non-chromate type of galvanizing material, the method proposed in the following publication is mentioned.

Japanese Patent Application Laid-Open No. 1-104783 discloses an alcohol solution containing one or two or more of an alkoxide or acetylacetonate salt of Si, Ti, Zr, Al, W, Ce, Sn, Y, or zinc, aluminum or A method for producing a surface-treated steel sheet is disclosed, which is coated on a zinc-aluminum alloy coated steel sheet and heated to 200 to 500 ° C. to form an oxide film of a metal contained in the solution on the surface of the steel sheet. However, this manufacturing method requires the use of flammable alcohol, and furthermore, it requires a considerably high temperature when forming the film, there is a problem in the working environment and energy cost.

Under the above circumstances, the surface treatment of zinc-plated materials is similar to that of aluminum-based or magnesium-based materials, and does not contain harmful chromium in the treatment liquid. This possible surface treatment liquid is not established.

The present invention is to solve the above problems with the prior art, and specifically to provide a metal surface treatment composition and surface treatment liquid and surface treatment method capable of imparting excellent corrosion resistance and coating film adhesion to the metal surface. It is.

The present inventors earnestly examined the means for solving the above-mentioned problems with the prior art. As a result, specific amounts of Al (C ₅ H ₇ O ₂ ) ₃ , V (C ₅ H ₇ O ₂ ) ₃ , VO (C ₅ H ₇ O ₂ ) ₂ , Zn (C ₅ H ₇ O ₂ ) ₂ and Surface treatment composition containing at least one metal acetylacetonate selected from Zr (C ₅ H ₇ O ₂ ) ₄ and at least one compound selected from a water soluble inorganic titanium compound and a water soluble inorganic zirconium compound in a specific ratio. The present invention has been completed by discovering that a chemical conversion film having excellent corrosion resistance and coating film adhesion can be formed on a metal surface by using a surface treatment liquid using this composition.

That is, the composition for metal surface treatment of the present invention is Al (C ₅ H ₇ O ₂ ) ₃ , V (C ₅ H ₇ O ₂ ) ₃ , VO (C ₅ H ₇ O ₂ ) ₂ , Zn (C ₅ H ₇ At least one metal acetylacetonate selected from the group consisting of O ₂ ) ₂ and Zr (C ₅ H ₇ O ₂ ) ₄ , and at least one compound selected from a water-soluble inorganic titanium compound and a water-soluble inorganic zirconium compound. It is characterized by containing in a weight ratio of 5000-5000: 1.

The surface treatment liquid of the present invention is Al (C ₅ H ₇ O ₂ ) ₃ , V (C ₅ H ₇ O ₂ ) ₃ , VO (C ₅ H ₇ O ₂ ) ₂ , Zn (C ₅ H ₇ O ₂ ) 0.01 to 50 g / L of at least one metal acetylacetonate selected from ₂ and Zr (C ₅ H ₇ O ₂ ) ₄ , and 0.01 to 50 g / L of the water-soluble inorganic titanium compound and the water-soluble inorganic zirconium compound. It contains -50 g / L and has a pH of 2.0-7.0, It is characterized by the above-mentioned.

Further, the surface treatment method of the present invention is an organic-inorganic composite chemical composition having a film weight of 5 to 2000 mg / m ² by contacting the metal surface treatment liquid with aluminum or its alloy, magnesium or its alloy, or zinc or its alloy. It is a metal surface treatment method characterized by forming a film.

Next, the structure of this invention is demonstrated in detail.

The surface treatment composition of the present invention is Al (C ₅ H ₇ O ₂ ) ₃ , V (C ₅ H ₇ O ₂ ) ₃ , VO (C ₅ H ₇ O ₂ ) ₂ , Zn (C ₅ H ₇ O ₂ ) ₂ And at least one metal acetylacetonate selected from the group consisting of Zr (C ₅ H ₇ O ₂ ) ₄ , at least one compound selected from a water-soluble inorganic titanium compound, and a water-soluble inorganic zirconium compound as essential components. .

In the present invention, inorganic metal compounds such as metal acetylacetonate, titanium and zirconium, such as metal acetylacetonate and titanium, metal acetylacetonate and zirconium, or metal acetylacetonate and titanium and zirconium, It is considered that the formation of the organic-inorganic composite film is the most important, and in doing so, the corrosion resistance of the formed chemical conversion film is particularly improved.

Metal acetylacetonates, which are essential components of the surface treatment composition of the present invention, include Al (C ₅ H ₇ O ₂ ) ₃ , V (C ₅ H ₇ O ₂ ) ₃ , VO (C ₅ H ₇ O ₂ ) ₂ , Zn ( At least one member selected from the group consisting of C ₅ H ₇ O ₂ ) ₂ , and Zr (C ₅ H ₇ O ₂ ) ₄ .

As the water-soluble inorganic titanium compound or water-soluble inorganic zirconium compound which is an essential component of the surface treatment composition of the present invention, one or two or more selected from sulfates, oxysulfates, nitrates, phosphates, chlorides, ammonium salts and fluorides of titanium or zirconium can be used. There is no restriction | limiting in particular as long as it is a water-soluble inorganic compound. These water-soluble inorganic titanium compounds and water-soluble inorganic zirconium compounds are precipitated in the form of Ti, Zr oxides, phosphates or fluorides on the surface of the metal to be treated, and an organic-inorganic complex formed between the metal acetylacetonates deposited at the same time. It becomes the skeletal part of the film. The presence of Ti and Zr improves the barrier property (shielding force) to the corrosive environment of the film, and as a result, it is possible to form a film having better corrosion resistance and coating adhesion than when the metal acetylacetonate is used alone. .

The blending ratio of the metal acetylacetonate and the water-soluble inorganic compound needs to be 1: 5000 to 5000: 1. Preferably it is 1: 100-400: 1, More preferably, it is 1: 50-100: 1, More preferably, it is 1: 10-10: 1. If this weight ratio is less than 1: 5000, the corrosion resistance of the formed organic-inorganic composite film is poor. Conversely, if it exceeds 5000: 1, it becomes difficult to form an organic-inorganic composite film.

Next, the metal surface treatment liquid of the present invention basically uses the surface treatment composition and water.

First, the content of the metal acetylacetonate in the treatment liquid is preferably in the range of 0.01 to 50 g / L, more preferably in the range of 0.1 to 20 g / L. Even if the content of the metal acetylacetonate is less than 0.01 g / L, a chemical conversion film is formed, but corrosion resistance and coating film adhesion are poor, which is not preferable. And even if it exceeds 50 g / L, a good chemical film is formed, but the effect is saturated, and the cost of a process liquid becomes high and it is economically useless.

The content of the water-soluble inorganic compound and the water-soluble inorganic zirconium compound is preferably in the range of 0.01 to 50 g / L, more preferably in the range of 0.05 to 10 g / L. Even if the content is less than 0.01 g / L, a chemical conversion film is formed, but since corrosion resistance is poor, it is not preferable. Moreover, even if it exceeds 50 g / L, a favorable chemical conversion film will be formed, but the effect will be saturated and a cost will become high, and it is economically useless.

The pH of the surface treatment liquid of this invention should be adjusted to the range of 2.0-7.0. More preferably, it is the range of pH 3.0-6.0. If the pH is less than 2.0, it is not preferable because it causes the appearance unevenness due to excessive etching on the surface of the metal material or the metal acetylacetonate becomes difficult to precipitate on the metal surface. If the pH exceeds 7.0, it is not preferable because formation of a chemically resistant film having excellent corrosion resistance is difficult or since metal ions contained in the treatment liquid easily form precipitates, which may cause problems in the safety of the liquid. When adjusting the pH of the surface treatment liquid of this invention to the range of 2.0-7.0, if necessary, acids, such as nitric acid, a sulfuric acid, phosphoric acid, hydrofluoric acid, and hydrofluoric acid, and sodium hydroxide, sodium carbonate, potassium hydroxide, ammonium hydroxide, etc. Alkali can be used.

In the surface treatment of the present invention, since the metal ions such as aluminum, magnesium, zinc, and the like are eluted from the treated metal material into the surface treatment liquid, the stability of the treatment liquid may be remarkably lowered. In this case, these metal ions are chelated. For this purpose, organic acids such as gluconic acid, heptogluconic acid, oxalic acid, tartaric acid, organic phosphonic acid and ethylenediaminetetraacetic acid or alkali metal salts thereof may be added to the treatment liquid as a blocking agent.

In addition, in the present invention, hydrogen peroxide, tungstic acid and salts thereof, molybdate and salts thereof, permanganic acid and salts thereof, and tert-butyl hydroxide [(CH ₃ ) ₃ CO— You may use together oxidizing agents, such as water-soluble organic peroxides, such as OH].

The coating weight of the organic-inorganic composite chemical conversion film formed by the above method is preferably in the range of ⁵ to 2000 mg / m ² , and more preferably in the range of 50 to 500 mg / m ² . If the film weight is less than 5 mg / m ² , corrosion resistance and coating film adhesion may be insufficient, which is not preferable. And even if the film weight exceeds 2000 mg / ㎡, the corrosion resistance is excellent, but the effect is saturated, the cost is high, it is economically useless. Moreover, when a film weight exceeds 2000 mg / m <^2> , there exists a tendency for coating film adhesiveness to fall and also the appearance unevenness of a film becomes remarkable, and also it is unpreferable in these respects.

The metal constituents of aluminum, vanadium, zinc, zirconium, and titanium, which are constituents of the chemical conversion film, are not particularly limited in terms of their presence in the coating, such as their bonding state, oxidation state, and polymerization state.

Subsequently, by contacting with the surface treatment liquid of this invention, aluminum or its alloy, magnesium or its alloy, or zinc or its alloy, the chemical conversion film excellent in corrosion resistance and coating-film adhesiveness can be formed. Hereinafter, the method of surface-treating various metal materials is demonstrated.

The surface treatment liquid of this invention is applied by the process shown below as a preferable example.

1) Surface cleaning: Degreasing (any acid, neutral, alkali or solvent) may be used

2) defensive

3) Surface treatment with the treatment liquid of the present invention

4) defensive

5) Deionized water washing

6) dry

And about the surface treatment liquid of this invention, it is preferable to make it contact the surface of a metal material on the conditions of the temperature of 10-80 degreeC, and the time of 1-600 second. If the contact temperature is less than 10 DEG C, the reactivity between the treatment liquid and the metal surface is insufficient, and a good chemical film is not formed. If the contact temperature exceeds 80 DEG C, the chemical film is formed, but the energy cost is high and it is economically useless. And, if the treatment time is less than 1 second, a chemically resistant film having excellent corrosion resistance is not formed. On the other hand, even if the time exceeds 600 seconds, there is no improvement in the corrosion resistance and coating film adhesion of the resulting chemical film.

In the present invention, the contact method with the surface treatment liquid may be either a dipping method or a spray method.

The aluminum or aluminum alloy material to which the surface treatment composition and the surface treatment liquid of the present invention is applied includes a metal made of pure aluminum and an aluminum alloy, and the aluminum alloy is, for example, Al-Cu, Al-Mn, Al-Si. , Alloys of various components such as Al-Mg, Al-Mg-Si, Al-Zn-Mg, and metal materials (such as aluminum plated steel sheets) coated with Al or Al alloys.

And magnesium or magnesium alloy materials include metals of pure magnesium and magnesium alloys, and magnesium alloys include alloys of various component systems such as Mg-Al-Zn, Mg-Zn and Mg-Al-Zn-Mn, for example. .

In addition, zinc or zinc alloy is a metal material especially Zn-plated, such as hot-dip galvanized steel, alloyed hot-dip galvanized steel, Al-Zn alloy galvanized steel (galvan, galvalume), galvanized steel and alloy galvanized steel, etc. Include.

The aluminum and aluminum alloy materials, magnesium and magnesium alloy materials, zinc and alloy materials are not limited in shape and size, and include, for example, plate materials and various molded articles. In addition, the surface of these materials may be present in at least a part of a predetermined metal. For example, the surface may be rolled or plated, or further subjected to roughening, activation or the like by shot blasting, acid or alkali. good.

EXAMPLE

Hereinafter, the effect of the surface treatment composition, the surface treatment liquid, and the surface treatment method of the present invention will be described in more detail with Examples.

Examples 1-5 and Comparative Examples 1-4

[Publication Materials]

As the surface-treated aluminum alloy material, an Al-Mn alloy plate (JIS3004) was used (dimensions: 150 mm x 70 mm, plate thickness 0.2 mm).

As the surface-treated magnesium alloy material, a die cast plate of magnesium alloy AZ91D specified in JIS H2222 was used (dimensions: 150 mm x 100 mm, plate thickness 1 mm).

An alloyed zinc galvanized steel sheet was used as the surface-treated zinc plating material (dimensions: 150 mm x 70 mm, plate thickness 0.8 mm).

[Processing Conditions]

Next step ① ② ③ ④ ⑤ The surface treatment board was constructed by the process of (6).

① Degreasing (43 ℃, 2 minutes, dipping method)

A commercial alkaline degreaser (trade name: a mixed aqueous solution of 2% of FineCleaner L4460A and 1.2% of FineCleaner L4460B, both manufactured by Nippon Parkarizing Co., Ltd.) was used.

② Water washing (room temperature, 30 seconds, spray method)

③ Surface treatment (immersion method)

Surface treatment was carried out with the surface treatment liquid and the treatment conditions of the composition shown in Table 5 and Table 6. The substance used by the surface treatment liquid of Examples 1-5 and Comparative Examples 1-4 is shown in Table 1. In addition, the weight of each substance shown in the column of the process liquid composition of Table 2 and Table 3 is the value converted into the pure component.

And the surface treatment conditions of Comparative Examples 5-9 are as showing below.

④ Washing (room temperature, 30 seconds, spray method)

⑤ Deionized water washing (room temperature, 30 seconds, spray method)

⑥ Heat drying (80 ℃, 3 minutes, hot air oven)

TABLE 1

Metal acetylacetonate used for the surface treatment liquid of Examples 1-5 and Comparative Examples 1-4

sign Source a Aluminum Acetyl Acetonate Al (C ₅ H ₇ O ₂ ) b Vanadium acetylacetonate V (C ₅ H ₇ O ₂ ) ₃ c Vanadil acetylacetonate VO (C ₅ H ₇ O ₂ ) ₂ d Zinc acetylacetonate Zn (C ₅ H ₇ O ₂ ) ₂ e Zirconium Acetylacetonate Zr (C ₅ H ₇ O ₂ ) ₄

TABLE 2

Water-soluble titanium compound used for the surface treatment liquid of Examples 1-5 and Comparative Examples 1-4

sign Source end 40% Titanium Hydrofluoric Acid H ₂ TiF ₆ I 24% Titanium Sulfate Ti (S0 ₄ ) ₂

TABLE 3

Water-soluble zirconium compound used for the surface treatment liquid of Examples 1-5 and Comparative Examples 1-4

sign Source end 20% Zirconic Hydrofluoric Acid H ₂ ZrF ₆ I Ammonium Zirconide (NH ₄ ) ₂ ZRF ₆

TABLE 4

PH adjuster used for the surface treatment liquid of Examples 1-5 and Comparative Examples 1-4

sign Source end 67.5% NH ₃ I 40% Hydrofluoric Acid H ₂ SiF ₆ All 25% ammonia water NH ₄ OH

Comparative Example 1 is a comparative example in which only metal acetylacetonate is used as a treatment liquid component to form a single film of metal acetylacetonate.

Comparative Example 2 is a comparative example in which only a water-soluble inorganic titanium compound is used as a treatment liquid component to form a single film of the inorganic titanium compound.

Comparative Example 3 is a comparative example in which an inorganic composite film composed of titanium and zirconium that does not contain a metal acetylacetonate is used as a treatment liquid composition of a water-soluble inorganic titanium compound and a water-soluble inorganic zirconium compound.

Comparative Example 4 is a comparative example in which a film having a very low coating weight is formed.

Comparative Example 5

A 2% aqueous solution of a commercially available zirconium phosphate surface treating agent (trade name: Arozin 4040, manufactured by Nippon Parka Co., Ltd.) was used for the surface treatment. The solution was then subjected to the Al alloy sheet described above at a temperature of 50 ° C., a time of 60 seconds, and a spray method to evaluate corrosion resistance and coating film adhesion.

Comparative Example 6

A commercially available phosphate chromate surface treatment agent (trade name: a mixed aqueous solution of 4% of Achromo K702SL and 0.3% of Arukuromu K702AC, both manufactured by Nippon Parka Co., Ltd.) was used for the surface treatment. The solution was then subjected to the Al alloy sheet described above at a temperature of 50 ° C. for a time of 20 seconds and under the spray method to evaluate corrosion resistance and coating film adhesion.

Comparative Example 7

A 7% aqueous solution of a commercial chromic acid chromate surface treatment agent (registered trademark: Arukuromu 713M, manufactured by Nippon Parka Co., Ltd.) was used for the surface treatment. The solution was then subjected to the Al alloy plate, the Mg alloy plate, and the Zn plated steel sheet at a temperature of 40 ° C., a time of 60 seconds, and the immersion method to evaluate corrosion resistance and coating film adhesion.

Comparative Example 8

For the surface treatment, a treatment liquid according to MIL-M-3171C (TYPE III) containing sodium dichromate as a main component was used. And this liquid was performed to the said Mg alloy plate on the temperature of 95 degreeC, time 30 second, and the immersion method, and corrosion resistance and coating film adhesiveness were evaluated.

Comparative Example 9

After degreasing of ① and washing with ② above, 0.1% aqueous solution of a commercially available titanium-based surface modifier (registered trademark: Pureparene 4040, manufactured by Nippon Parker Co., Ltd.) was carried out under the conditions of a temperature of 25 ° C., a time of 30 seconds, and a dipping method. After that, at room temperature, 30 seconds, after washing under spraying conditions, an aqueous solution of a commercially available zinc phosphate surface treatment agent for surface treatment (registered trademark: 5% of Farobond L3020, 0.5% of additive 4813, 2% of additive 4856, and neutralizer 4055) 1% of the mixed aqueous solution; all were manufactured by Nippon Parkarizing Co., Ltd.). The solution was then subjected to the above-described Zn plated steel sheet at a temperature of 43 ° C., time 120 seconds, and immersion method to evaluate corrosion resistance and coating film adhesion.

[Assessment Methods]

(1) film weight

The film weight of the entire organic-inorganic composite film was measured using a fluorescence X-ray analyzer or a 5 wt% aqueous solution of chromic acid, 90 ° C., and 5 minutes immersion.

(2) corrosion resistance

Evaluation of corrosion resistance used the salt spray test based on JIS-Z-2371. The corrosion occurrence condition of the surface treatment plate after the salt spray test was visually evaluated.

The evaluation criteria of salt spray time and corrosion resistance for each surface treated specimen are as follows.

Spray time

Al alloy plate ...... 480 hours

Mg alloy plate ....... 24 hours

Zn plated steel sheet ...... 120 hours

Evaluation standard

◎: less than 10% of corrosion area,

: Corrosion area more than 10%, less than 30%

△: corrosion area ratio of 30% or more, less than 50%,

X: corrosion area ratio of 50% or more,

(3) coating film adhesion

Apply an epoxy resin paint (manufactured by Japan Paint Co., Ltd.) on the surface of the Al alloy sheet, Mg alloy sheet or Zn plated steel sheet subjected to the conditions of Examples 1 to 5 and Comparative Examples 1 to 9 to have a dry film thickness of 10 µm. It coated and baked at 200 degreeC for 10 minutes. Subsequently, 100-mm-wide checkerboard eyes were formed with a cutter in the center of the paint plate and immersed in deionized boiling water for 60 minutes. And after air-drying the coating plate, the cellophane tape peeling test was done and the coating film adhesiveness was evaluated as the residual water of the board | substrate which did not peel at this time.

And the more this residual number, the more excellent coating film adhesiveness, and if it is 98 or more, it is practically enough performance.

The evaluation results are shown in Tables 5 and 6.

The chemical conversion film formed by the surface treatment liquid of this invention from Table 5 and Table 6 has the corrosion resistance and coating-film adhesiveness equivalent to the conventional chromate film, and the organic-metal which acetylacetonate and Ti / Zr of a considerable film weight coexisted. It has been found that excellent corrosion resistance can be realized by forming an inorganic composite film.

As apparent from the above description, by applying the surface treatment composition and the surface treatment liquid according to the present invention to an aluminum-containing material, a magnesium-containing material, or a galvanized material, it is possible to form a chemical conversion film having excellent corrosion resistance and coating film adhesion. .

Therefore, the surface treatment liquid of this invention is extremely useful practically.

TABLE 5

Composition, conditions and evaluation test results of the surface treatment solution in Examples 1 to 5

TABLE 6

Composition, conditions and evaluation test results of the surface treatment liquid in Comparative Examples 1 to 9

Claims (3)

Al (C ₅ H ₇ O ₂ ) ₃ , V (C ₅ H ₇ O ₂ ) ₃ , VO (C ₅ H ₇ O ₂ ) ₂ , Zn (C ₅ H ₇ O ₂ ) ₂ and Zr (C ₅ H ₇ Containing at least one metal acetylacetonate selected from the group consisting of O ₂ ) ₄ and at least one compound selected from a water-soluble inorganic titanium compound and a water-soluble inorganic zirconium compound in a weight ratio of 1: 5000 to 5000: 1. A metal surface treatment composition. Al (C ₅ H ₇ O ₂ ) ₃ , V (C ₅ H ₇ O ₂ ) ₃ , VO (C ₅ H ₇ O ₂ ) ₂ , Zn (C ₅ H ₇ O ₂ ) ₂ and Zr (C ₅ H ₇ 0.01 to 50 g / L of at least one metal acetylacetonate selected from the group consisting of O ₂ ) ₄ and 0.01 to 50 g / L of at least one compound selected from the water-soluble inorganic titanium compound and the water-soluble inorganic zirconium compound. It contains L and has a pH of 2.0-7.0, The metal surface treatment liquid characterized by the above-mentioned. Forming an organic-inorganic composite coating film having a coating weight of 5 to 2000 mg / m ² by contacting the metal surface treatment liquid according to claim 2 with aluminum or its alloy, magnesium or its alloy, or zinc or its alloy. A method of surface treatment of metals.