JP2007039727A - Alkaline zinc alloy electroplating solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroplating solution which is excellent in corrosion resistance and throwing power. <P>SOLUTION: The alkaline zinc alloy electroplating solution contains (A) Zn ions in a content of 1-600g/L, (B) iron group element ions in a content of 1-600 g/L, (C) a tungstic acid-based compound in a content of 0.1-600 g/l as W ion and (D) a basic compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an alkaline electrogalvanized plating solution for forming a film having a role of plating and surface treatment, an electrogalvanized metal material obtained by using the plating solution, and further, the electrogalvanized plating The present invention relates to a coated article obtained by painting a metal material with a paint.

As the surface treatment of zinc-based plated metal materials used in automobiles, home appliances, building materials, etc., chromate treatment and zinc phosphate treatment are generally performed, but the toxicity of chromium is a problem. In the chromate treatment, there are problems that chromate fumes are volatilized in the treatment process, wastewater treatment equipment is expensive, and chromic acid is eluted from the chemical conversion coating. Hexavalent chromium compounds are extremely harmful because many public institutions, including IARC (International Agency for Research on Cancer Review), have designated them as carcinogenic substances for the human body.
In addition, in zinc phosphate treatment, after zinc phosphate treatment, rinsing treatment with chromic acid is usually performed, so there is a problem of chromium treatment, as well as treatment accelerators in zinc phosphate treatment agents, wastewater treatment of metal ions, etc. There is a problem of sludge treatment due to elution of metal ions from the treated metal. Furthermore, it is desired to develop a plating film having high throwing power and excellent corrosion resistance and adhesion to a coating film.

Conventionally, there has been disclosed a bright metal plating bath containing at least one metal of water-soluble molybdenum or tungsten compound and at least one organic compound in an acidic bath containing zinc as a main component ( Patent Document 1).
In addition, there is an electrogalvanizing method in which one or more cobalt water-soluble compounds are added to an acidic electrogalvanizing bath, and further a water-soluble compound of molybdenum, tungsten, or iron is added (Patent Document 2).
In addition, in a method for forming a protective film on the surface of a metal, an invention relating to a metal surface treatment method using a liquid composition containing zinc and iron and maintaining a pH within a range of 0.5 to 5.0 is disclosed. (Patent Document 3). In addition, a method for producing a Zn-based alloy containing one or more selected from the group consisting of cobalt, iron, nickel, chromium and manganese (Patent Document 4). In addition, an invention relating to a composite electroplated steel sheet in which oxide particles adsorbed with a corrosion inhibitor in addition to zinc and iron are disclosed (Patent Document 5).

Japanese Patent Laid-Open No. 49-11735 Japanese Patent Publication No. 47-16522 JP-A-5-195244 JP 2000-309897 A JP 2001-254195 A

However, since these electro-zinc alloy plating solutions do not provide sufficient throwing power and corrosion resistance, they are not applicable to fields that require strict corrosion resistance, such as automobile parts, particularly automobile parts having uneven shapes and bag structures. It was a difficult situation.
Accordingly, an object of the present invention is to provide an electroplating solution that is excellent in corrosion resistance and throwing power.

  As a result of intensive studies to solve the above problems, the present inventors have found that (A) Zn ion is 1 to 600 g / L, (B) iron group element ion is 1 to 600 g / L, and (C) tungstic acid. The alkaline electroplating solution containing 0.1 to 600 g / L of the W compound as a W ion and (D) a basic compound has found that the throwing power is improved, and a plating film having excellent corrosion resistance has been obtained. .

  Since the electroplating metal material to which the alkaline electroplating solution of the present invention is applied is excellent in throwing power, excellent corrosion resistance can be obtained even in a coated object having an uneven shape or a bag structure. The electrozinc alloy-plated metal material obtained using the plating solution of the present invention is also excellent in adhesion to a coating film coated thereon, and therefore a coated article having a multilayer coating film excellent in corrosion resistance is obtained. Can do. The alkaline electroplating solution of the present invention is a non-polluting type plating solution that has little discharge of waste liquid and industrial waste and is environmentally friendly.

Alkaline electroplating solution The composition of the alkaline electroplating solution of the present invention contains Zn ions (A), iron group element ions (B), tungstic acid compounds (C), and basic compounds (D). This will be described in detail below.

Zn ion (A):
Zn ions which are the component (A) of the alkaline electroplating solution of the present invention constitute the main component of the plating layer. Zn ions are added to the plating bath in the form of chloride, sulfate, fluoride, cyanide, oxide, organic acid salt, phosphate or simple metal. Examples include zinc chloride, zinc sulfate, and zinc oxide. Of these, zinc sulfate is preferred.
The compounding quantity of Zn ion (A) is 1-600 g / L, Preferably it is 50-300 g / L, More preferably, it is 60-250 g / L. The unit g / L is the mass per liter of the plating bath and has the same meaning hereinafter.

Iron group element ions (B):
The iron group element ions (B) used in the present invention are preferably selected from Ni ions, Co ions and Fe ions, and among them, Fe ions are preferable from the viewpoint of corrosion resistance.
The iron group element ion (B) is added to the plating bath in the form of chloride, sulfate, fluoride, cyanide, oxide, organic acid salt, phosphate, simple metal or hydrate. Examples thereof include iron chloride, iron sulfate, and iron oxide. Among these, iron sulfate is preferable.
The compounding amount of the iron group element ion (B) is 1 to 600 g / L, preferably 50 to 300 g / L, and more preferably 60 to 250 g / L.

Tungstic acid compound (C):
Examples of the tungstic acid compound (C) include tungstic acid, tungstate, phosphotungstic acid, and phosphotungstate. Examples of the salt include ammonium salt, potassium salt, calcium salt, sodium salt, and the like. Among them, ammonium salt or sodium salt is preferable. In particular, ammonium tungstate, ammonium phosphotungstate, sodium tungstate and sodium phosphotungstate are preferred from the viewpoint of corrosion resistance. Among these, sodium tungstate is preferable.
The compounding quantity of a tungstic acid type compound (C) is 0.1-600 g / L as W ion, Preferably it is 5-300 g / L, More preferably, it is 10-100 g / L.

Basic compound (D):
The basic compound (D) used in the present invention is selected from those that are chemically stable even when mixed with the above metal ions. By adding the basic compound (D) to the plating solution, the “throwing power” is improved, so that, for example, excellent corrosion resistance can be obtained even in an article having an uneven shape or bag structure such as an automobile part. it can.
As the basic compound (D), an alkali metal or alkaline earth metal hydroxide or an amine compound is preferably used. Examples of the alkali metal or alkaline earth metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and barium hydroxide. Examples of the amine compound include ammonia; primary amines such as ethylamine, propylamine, butylamine, benzylamine, monoethanolamine, neopentanolamine, 2-aminopropanol, and 3-aminopropanol; diethylamine, diethanolamine, di- Secondary monoamines such as n- or di-iso-propanolamine, N-methylethanolamine, N-ethylethanolamine; dimethylethanolamine, trimethylamine, triethylamine, triethanolamine, triisopropylamine, methyldiethanolamine, dimethylaminoethanol Tertiary monoamines such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine And polyamines such as ethylenediamine (EDA) and triethylenetetramine. Among these, alkali metal hydroxides are preferable, such as sodium hydroxide, potassium hydroxide, and lithium hydroxide. Moreover, bath stability can be improved by using an amine compound in combination. Among the amine compounds, hydroxyl group-containing triethanolamine and 2-aminopropanol are preferable.
The compounding quantity of a basic compound (D) is 1-600 g / L as solid content, Preferably it is 10-300 g / L, More preferably, it is 50-200 g / L.

Corrosion inhibiting pigment and / or ceramic particles:
In the present invention, by combining a corrosion-inhibiting pigment and / or ceramic particles that can be precipitated as discontinuous particles from the electroplating solution, functions such as high corrosion resistance and paint adhesion can be imparted.

As the corrosion-inhibiting pigment, generally known pigments can be used. Preferred examples include phosphates, molybdates, metaborates and silicates. Specifically, aluminum phosphomolybdate, tripolyphosphorus Examples include aluminum dihydrogen oxide. Examples of the ceramic particles include oxides such as Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , Y ₂ O ₂ , ThO ₂ , CeO ₂ , and Fe ₂ O ₃ ; B ₄ C, SiC, and WC. , ZrC, TiC, graphite, graphite such as fluorinated graphite; nitrides such as BN, Si ₃ N ₄ , TiN; borides such as Cr ₃ B ₂ , ZrB ₂ ; 2MgO · SiO ₂ , MgO · SiO ₂ , ZrO Examples thereof include silicates such as ₂ · SiO ₂ .
The blending amount of the corrosion-inhibiting pigment and / or ceramic particles is desirably in the range of 5 to 300 g per liter of the plating bath. In addition, the smaller the size of the particles, the better the dispersion stability. Therefore, ultrafine particles of 1 μm or less are preferable. Further, the amount of eutectoid in the plating matrix is desirably controlled in the range of 1 to 30% by weight, particularly 1 to 10% by weight with respect to the total precipitation amount. When the amount of eutectoid is small, the effect of improving the corrosion resistance is not exhibited, and when it exceeds 30% by weight, the plating film becomes brittle or the adhesion with the substrate is lowered, which causes a problem.

Further, a corrosion-inhibiting organic compound may be added. Examples of preferable corrosion-inhibiting organic compounds include alkynes, alkynols, amines or salts thereof, thio compounds, aromatic carboxylic acid compounds or salts thereof, and heterocyclic compounds. Is mentioned.
Among these, alkynes are organic compounds containing a carbon-carbon triple bond, and examples thereof include pentine, hexyne, heptin, octyne and the like. The alkynols are organic compounds having one or more hydroxyl groups in the alkynes, and examples thereof include propargyl alcohol, 1-hexyn-3-ol, and 1-heptin-3-ol. An amine means an organic compound containing one or more nitrogen atoms in the molecule, and includes both aliphatic and aromatic compounds. Examples of such amines include octylamine, nonylamine, decylamine, laurylamine, tridicylamine, cetylamine and the like.

  A thio compound means an organic compound containing one or more sulfur atoms in the molecule. Examples of such a thio compound include decyl mercaptan, cetyl mercaptan, thiourea and the like. A heterocyclic compound means an organic compound containing atoms other than carbon as a ring constituent element in a cyclic molecule. Examples of such a heterocyclic compound include pyridine, benzothiazole, benzotriazole, and quinoline. And indole. Examples of the aromatic carboxylic acid compound include benzoic acid, salicylic acid, toluic acid, naphthalene carboxylic acid, gallic acid, and tannic acid. In addition, about amines and a carboxylic acid compound, it is also possible to use the salt, and an equivalent effect can be acquired also in this case. As the salt, in the case of amines, acid addition salts such as sulfates and hydrochlorides, and in the case of aromatic carboxylic acid compounds, metal salts such as alkali metal salts and zinc salts and ammonium salts can be used.

  The amount of the corrosion-inhibiting organic compound added to the anteater electroplating bath of the present invention is 0.1 to 10% by weight in the case of alkynes and alkynols, and 3 to 3 in the case of amines or salts thereof. It is desirable to adjust to 10% by weight, 0.2 to 5% by weight for thio compounds, 1 to 10% by weight for heterocyclic compounds, and 3 to 8% by weight for aromatic carboxylic acid compounds or salts thereof.

The alkaline electroplating solution of the present invention may further contain a complexing agent, a pit inhibitor, a mist inhibitor, an antifoaming agent, etc. for stabilizing metal ions.
Examples of the complexing agent include oxycarboxylates such as citrate, tartrate and gluconate, amino alcohols such as monoethanolamine, diethanolamine and triethanolamine, ethylenediamine (EDA), diethylenetriamine and triethylenetetramine. Selected from the group consisting of polyamines such as ethylenediaminetetraacetate, aminocarboxylates such as nitroacetate, polyhydric alcohols such as sorbit and pentaerythritol, and mixtures thereof.

  Further, the plating solution may contain additives that are usually used for the purpose of improving burn-in at high current density and “throwing power” at low current density. Examples of these include amine and epihalohydrin reactants, polyethylene polyamines, other quaternary amine polymers, urea, gelatin, polyvinyl alcohol, aldehydes, and the like.

  The alkaline electroplating solution of the present invention is capable of forming a plating film having excellent throwing power by depositing a metal by electroplating in the same manner as in the past, and thus obtaining a coated article having excellent corrosion resistance. Can do.

  Since the electroplating solution is alkaline, the pH is more than 7, preferably 10 or more, more preferably 12 or more. The bath temperature is about 10 to 80 ° C, preferably 20 to 50 ° C. The thickness of the plating is 0.5 to 30 μm, preferably about 1 to 10 μm.

Throwing power:
Throwing power is evaluated by the Hull cell test. Specifically, a trapezoidal Hull cell test tank (electrodeposition test tank) as shown in FIG. 1 is used, and a power source, ammeter, voltmeter, etc. are connected as shown in FIG. Connect to the side and measure.
Measurement of “throwing power” by the Hull cell test is performed as follows. First, the electroplating solution is put in a Hull cell test tank to a constant temperature (for example, 25 ° C.), and a constant current (for example, 10 A) is applied to the electrode and the object to be coated for a certain period of time (for example, 180 seconds). Obtain a test plate. Measure the distance from the high current density side to the defective plating area on the low current density side on the part 4 which is 1/2 of the liquid surface 1 and the center line 3 of the test plate. 5 The “throwing power” when the plating bath of the present invention is used is that the throwing length 5 is 90 mm or more, preferably 100 mm (the boundary between the plating surface and the object to be coated when the throwing power is good). As in b, the entire object can be covered with a plating film). FIG. 4 shows a photograph of a test plate subjected to a Hull cell test using the plating solution of the present invention as a bath. FIG. 5 shows a photograph of a test plate subjected to a hull cell test using a conventional plating solution as a bath. In the present invention, the throwing length 6 is sufficient and good plating is confirmed. However, in the conventional product, the plating portion 7 is very narrow, and the deposition of the plating film is hardly observed.

Electroplated metal material:
The electroplated metal material of the present invention can be obtained by electroplating a metal material using the alkaline electroplating solution. Examples of metal materials include iron-based materials such as plates, pipes, joints, clamps, bolts, nuts, and other processed materials such as automobiles, home appliances, or building materials that have irregular shapes or bag structures. Can be mentioned. Since the alkaline electroplating solution of the present invention is excellent in throwing power, it is possible to obtain an electroplated metal material that is excellent in corrosion resistance, which has not been conventionally available.

  Further, after the electroplating film is formed, the corrosion resistance can be further improved by post-treatment with an acidic aqueous solution of a compound containing at least one element selected from the group consisting of cobalt, nickel, titanium and zirconium. . Examples of the compound containing at least one element selected from the group consisting of cobalt, nickel, titanium, and zirconium include oxides, hydroxides, fluorides, complex fluorides, chlorides, and nitrates of these metal elements. , Sulfates, carbonates, and the like can be used. Specifically, cobalt nitrate, zirconium oxynitrate, titanium hydrofluoric acid, zircon hydrofluoric acid, ammonium titanium hydrofluoride, ammonium zircon ammonium hydrofluoride and the like are preferable. As mentioned.

The acidic aqueous solution of the compound containing these metal elements has a pH in the range of 1 to less than 7, but the pH can be adjusted with a basic compound such as sodium hydroxide, potassium hydroxide, or amines. You may add a complexing agent, a silica particle, etc. to acidic aqueous solution further as needed. The amount of the compound containing a metal element is preferably about 0.001 to 5 mol / l, particularly about 0.01 to 1 mol / l.
The post-treatment with an acidic aqueous solution is performed by, for example, treating the electroplated film by immersing a metal material in a treatment solution having a bath temperature of 20 to 80 ° C., preferably 30 to 60 ° C. for 5 seconds or more, preferably about 20 to 90 seconds. It can carry out by making it contact with a liquid.

Painted article:
The coated article of the present invention is obtained by painting a coating on the electroplated metal material obtained as described above. Since the electroplated metal material is excellent in coating film adhesion, the paint can be applied as it is without any surface treatment. Further, even when combined with a chromium-free environmentally-friendly surface treatment agent, excellent corrosion resistance is exhibited, and further excellent corrosion resistance can be exhibited by painting a paint.
When the paint is applied to the electroplated metal material of the present invention, it is not particularly limited, and any of curing methods such as a normal drying type, a thermosetting type, and an active energy ray curable type can be used. Any type of paint such as solvent-based paint, water-based paint, and powder paint may be used. In particular, when the electroplating solution composition of the present invention is applied to an automobile, it is common to sequentially apply an electrodeposition coating, an intermediate coating, and a top coating on the plating film, followed by baking.

  The use of painted metal materials can be used without particular limitation for applications that use conventional painted metal materials such as for building materials, home appliances, automobiles, and fastening parts. What is necessary is just to select suitably by the shape of a coating material, etc. For example, spraying, dip, electrodeposition, etc. are suitable when painting on molded products, and roll painting, curtain flow painting, etc. when painting on plate-like materials such as pre-coated metal materials Are preferably used.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited only to these Examples. “Parts” and “%” are “parts by weight” and “% by weight”.

Example of preparation of plating solution and electroplating metal material According to the composition shown in Table 1 below, plating solution No. 1-12 were obtained. Cold-rolled steel sheet (SPCC) with a thickness of 0.8 mm is alkali degreased and washed with water, and then each plating solution is adjusted to a liquid temperature of 25 ° C., and the current density is varied from 1 to 30 A / cm ² to perform electroplating. The plating metal material was obtained. The film thickness was measured with a fluorescent X-ray analyzer SEA5200 (manufactured by Seiko Instruments Inc.). The pH of each plating solution is shown in Table 1.

Comparative Examples 1-6
Except for the composition shown in Table 2, the plating solution No. 13-No. 18 was obtained and the steel sheet was electroplated. The pH of each plating solution is shown in Table 2.
Comparative Example 7
An electrogalvanized steel sheet (SECC material with a coating weight of 20 g / m ² : JIS G-3313) treated with phosphate (trade name: Palbond 3118, manufactured by Nippon Parkerizing Co., Ltd.) having a thickness of 0.8 mm was used.

Paint system 1
Metal materials obtained by applying Palbond # 3020 (manufactured by Nippon Parkerizing Co., Ltd., zinc phosphate treatment) to each of the plated metal materials obtained in Examples 1 to 12 and Comparative Examples 1 to 7, alkaline degreasing, washing with water and Drained and dried.
Next, “Magiclon 1000 White” (manufactured by Kansai Paint Co., Ltd., acrylic-melamine resin-based paint, white) is applied to each metal material so that the dry film thickness is 30 μm, and baked at 160 ° C. for 20 minutes. Each test coating was obtained.

Paint system 2
Using the plated metal materials obtained in Examples 1 to 12 and Comparative Examples 1 to 7, and Comparative Example 8 using an alloyed hot-dip galvanized steel sheet, Palbond # 3020 (Nihon Parkerizing Co., Ltd., zinc phosphate treatment), The surface was alkali degreased, washed with water and dried with water.
Next, Eleclon GT-10LF (trade name, epoxy resin / block isocyanate-cured cationic electrodeposition coating) manufactured by Kansai Paint Co., Ltd. is electrodeposited on each metal material, baked at 170 ° C. for 20 minutes, and dried. An electrodeposition coated plate having a thickness of 20 μm was obtained.
Next, an intermediate coating “Amirac TP-65 Gray” (manufactured by Kansai Paint Co., Ltd., amino alkyd resin system) is applied to the electrodeposited surface with a spray so that the dry film thickness is 30 μm, and at 140 ° C. Baked for 20 minutes. Thereafter, a top coat neoamylac # 6000 white (manufactured by Kansai Paint Co., Ltd., amino alkyd resin system) was applied by spraying so that the dry film thickness was 30 μm, and baked at 140 ° C. for 20 minutes to obtain each test plate.

Paint system 3
The steel bolt was degreased with alkali, washed with water, and then immersed in 1% sulfuric acid solution at room temperature for 30 seconds for activation treatment. Thereafter, using a batch type barrel plating apparatus, plating was performed with each of the plating solutions of Examples 1 to 12 and Comparative Examples 1 to 7. Then, after-treatment was performed by dipping in an acidic aqueous solution composed of 5 g / l of HNO ₃ and 15 g / l of (NH ₄ ) ₂ ZrF ₆ at 50 ° C. to prepare a test bolt.

Comparative Example 9
The steel bolt was degreased with alkali, washed with water, immersed in a 1% sulfuric acid solution at room temperature for 30 seconds for activation treatment, and then a zincate bath (metal zinc 10 g / l, sodium hydroxide 120 g / l) was used. Electrogalvanizing (5 μm) was applied. After that, a hexagonal chromium-containing chromate solution manufactured by YUKEN INDUSTRY CO., LTD .: Metas CY-6 was immersed for 10 seconds at 25 ° C. for chromate treatment to prepare a comparative bolt. The adhesion amount of the chromate film was 5 to 6 mg / dm ² .

  Examples 1 to 12 and Comparative Examples 1 to 9 were evaluated based on the following test methods. The results are also shown in Tables 1 and 2.

(Note 1) Metal ions:
Each metal ion in Table 1 and Table 2 is supplied from the following compound.
Zinc: ZnSO ₄ · 7H ₂ O
_Iron: FeSO 4 · _7H 2 O
_Cobalt: CoSO 4 · _7H 2 O
_Nickel: NiSO 4 · _7H 2 O
_{Tungsten: Na 2 WO 4 · 2H 2} O

(Note 2) Throwing power:
The test was performed according to the Halsel test method. In the test plate (65 mm × 100 mm × 0.8 mm), the distance (mm) from the high current density side to the defective plating portion generated on the low current density side was evaluated.

(Note 3) Bath stability:
Each plating bath was placed in a 1 L plastic container, stored at 50 ° C. for 4 weeks, and then filtered through a 500 mesh filter metal net.
◎: Filtration residue amount less than 5 mg / L ○: Filtration residue amount is 5 mg / L or more and less than 10 mg / L ○ △: Filtration residue amount is 10 mg / L or more and less than 15 mg / L △: Filtration residue amount is 15 mg / L More than and less than 20 mg / L x: Filtration residue amount is 20 mg / L or more

(Note 4) Top coat adhesion:
After immersing the test coating plate in boiling water at about 98 ° C. for 2 hours, it is pulled up and left at room temperature for 2 hours, and the coating surface of this test coating plate is cut into 11 grids that reach the substrate with a knife. 100 squares of 2 mm square were made. The cellophane pressure-sensitive adhesive tape was brought into close contact with the grid area, and the peeled area of the coating film when the tape was instantaneously peeled was evaluated according to the following criteria.
5: No peeling of the coating film is observed.
4: Although peeling of the coating film is observed, the peeling area is less than 10%.
3: The peeled area is 10% or more and less than 25%.
2: The peeled area is 25% or more and less than 50%.
1: The peeling area is 50% or more.

(Note 5) Top coat corrosion resistance:
A cross-cut reaching the base of the test coated plate coated with the top coat is put in, and after performing a salt spray test for 240 hours according to JIS Z-2371, the test coated plate is washed with water and dried, and then cellophane is applied to the cross-cut portion. The maximum peel width (one side, mm) from the crosscut portion when the adhesive tape was brought into close contact and peeled off instantaneously was measured.

(Note 6) Chipping resistance:
The test coating plate was fixed to a test piece holder of a stepping stone testing machine JA-400 type (manufactured by Suga Test Instruments Co., Ltd., chipping test apparatus) so as to be perpendicular to the stone jetting port, and at 0 ° C. to 0.degree. Granulated crushed stone of No. 7 was sprayed onto the coated surface with compressed air of 294MPs (3 kgf / cm ² ), and the degree of occurrence of coating scratches caused by this was visually observed and evaluated according to the following criteria.
A: The size of the scratch is quite small and the top coating film is scratched.
○: The size of the scratch is small and the intermediate coating film is exposed.
(Triangle | delta): Although the magnitude | size of a crack is small, the base metal material is exposed.
X: The size of the scratch is quite large, and the base metal material is also greatly exposed.

(Note 7) Water resistant secondary adhesion:
After dipping the test coating plate in warm water at 40 ° C for 10 days, create 11 100 mm 2 mm square cells by placing 11 vertical and horizontal scratches that reach the substrate with a knife on the coating surface of the test coating plate. did. The cellophane pressure-sensitive adhesive tape was brought into close contact with the grid area, and the peeled area of the coating film when the tape was instantaneously peeled was evaluated according to the following criteria.
5: No peeling of the coating film is observed.
4: Although peeling of the coating film is observed, the peeling area is less than 10%.
3: The peeled area is 10% or more and less than 25%.
2: The peeled area is 25% or more and less than 50%.
1: The peeling area is 50% or more.

(Note 8) 3-coat corrosion resistance:
A cross cut reaching the substrate is put on the painted plate, and after performing a salt spray test for 960 hours according to JIS Z-2371, it is washed with water and air-dried. The maximum peel width (one side, mm) from the cross cut portion when the cellophane adhesive tape was brought into close contact with the cut portion and peeled off instantaneously was measured.
○: No rust, swelling or the like is observed on the coated surface.
Δ: Rust, swelling, etc. are slightly observed on the coated surface.
X: The occurrence of rust and swelling on the coated surface is remarkably observed.

(Note 9) Salt water dip resistance:
Put a cross cut that reaches the base on the painted plate, immerse it in 5% saline solution at 50 ° C for 10 days, then wash and air dry it, and evaluate the general part of rust and blisters according to the following criteria, and the cross cut part The maximum peel width (one side, mm) from the cross-cut portion when the cellophane adhesive tape was brought into close contact with and peeled off instantaneously was measured.
○: No rust, swelling or the like is observed on the coated surface.
Δ: Rust, swelling, etc. are slightly observed on the coated surface.
X: The occurrence of rust and swelling on the coated surface is remarkably observed.

(Note 10) Bolt corrosion resistance:
A salt spray test (SST) was performed in accordance with JIS Z2371, and the corrosion resistance was evaluated based on the generation time of 10% white rust and 5% red rust.

  Since the electroplating metal material to which the alkaline electroplating solution of the present invention is applied is excellent in throwing power, a coated article having excellent corrosion resistance can be obtained in a coated object having a concavo-convex shape or a bag structure.

It is the schematic of a Hull cell test tank. It is the schematic which shows the electrical connection of a hull cell test method. It is the schematic which shows the measurement position of the cathode surface (test surface) of a hull cell test method. It is the photograph of the test board which performed the hull cell test using this invention goods as a plating bath. It is the photograph of the test plate which performed the hull cell test using the conventional product as a plating bath.

Explanation of symbols

1 Liquid level 2 Hull cell test chamber 3 Center line 4 of test plate 5 part of liquid level and center line of test plate 5 Length of throwing power a Plated surface and coated material when throwing power is poor Boundary b of the plating surface and the object to be coated when the throwing power is good 6 Length of throwing power (good throwing power)
7 Plating area (poor throwing power)

Claims (9)

(A) 1 to 600 g / L of Zn ions,
(B) 1 to 600 g / L of iron group element ions,
(C) 0.1 to 600 g / L of a tungstic acid compound as W ions, and (D) an alkaline electrozinc alloy plating solution containing a basic compound.   The alkaline electrolytic zinc alloy plating solution according to claim 1, wherein the iron group element ions (B) are Fe ions.   The alkaline electrogalvanic alloy plating according to claim 1 or 2, wherein the tungstic acid compound (C) is at least one compound selected from the group consisting of tungstic acid, tungstate, phosphotungstic acid and phosphotungstate. liquid.   The alkaline electrozinc alloy plating solution according to any one of claims 1 to 3, wherein the basic compound (D) contains at least one selected from an alkali metal hydroxide and an amine compound.   Furthermore, the alkaline electrozinc alloy plating liquid of any one of Claims 1-4 which contains 5-300 g / L of a corrosion inhibitor pigment and / or ceramic particle | grains.   The distance from the terminal on the high current density side to the defective plating part on the low current density side in the test plate obtained by adjusting the plating solution to a liquid temperature of 25 ° C. and conducting a Hull cell test at 10 A for 180 seconds. The alkaline electrozinc alloy plating solution according to any one of claims 1 to 5, wherein is at least 90 mm.   An electrozinc alloy-plated metal material obtained by electroplating the alkaline electrozinc alloy plating solution according to any one of claims 1 to 6 on a metal material.   An electrozinc alloy-plated metal material obtained by electroplating the alkaline electrozinc alloy plating solution according to any one of claims 1 to 6 on a metal material having an uneven shape.   A coated article obtained by coating a paint on the electrogalvanized metal material according to claim 7 or 8.