WO2005056883A1 - Electroplated coating of zinc alloy with excellent corrosion resistance and plated metal material having same - Google Patents

Abstract

Disclosed is an electroplated coating of a zinc alloy which contains no environmentally harmful chromium and still exhibits a high corrosion resistance equivalent to that of a Zn-Cr alloy plating. Also disclosed is a plated metal material having such a coating. The electroplated coating of a zinc alloy having excellent corrosion resistance is characterized by containing (A) 30-96 weight% of zinc, (B) 2-20 weight% of an iron group metal and (C) 2-50 weight% of tungsten.

Description

Zinc-based alloy electroplating film with excellent corrosion resistance and plated metal material using the same <Technical field>

 The present invention relates to a zinc-based alloy electroplated film having excellent corrosion resistance and a metal material using the same, and can be used in a wide range of fields such as automobiles, home electric appliances, and building materials.

 Akita

 <Background technology>

 book

 In response to the demand for higher corrosion resistance for metal materials used in automobiles, home appliances, building materials, etc., the use of zinc-based metal materials in which iron-based materials are coated with zinc or a zinc-based alloy is expanding. There are various methods for coating iron-based materials with zinc.As for plating, hot-dip zinc plating, which forms a plating film by immersing a base material in molten zinc or a zinc alloy, and zinc metal dissolved in an aqueous solution There is known electrogalvanizing which forms a plating film by depositing by electrolysis. Further, they are classified into acidic baths and alkaline baths depending on the liquid properties of the electro-zinc plating solution. Acidic baths include sulfuric acid baths, ammonium chloride baths, potassium chloride baths, and ammonium chloride'potassium chloride baths. Alkaline baths include cyanide baths and zincate baths, which are used according to their characteristics. However, metal materials used in automobiles, home appliances, building materials, etc., which are exposed to harsh environments, may not be able to obtain sufficient heat resistance in some cases, even if these plated metal materials are used. Is required to be improved. Under these circumstances, zinc-based alloy-coated metal materials such as zn-Fe, Zn-Ni, and Zn-Cr have been developed. Is disclosed to have high corrosion resistance (see, for example, Patent Document 1, Patent Document 2, Patent Document 3, etc.).

Zn-Cr alloy plating has a remarkable effect of suppressing corrosion due to Cr present in the film, and the film keeps a relatively low potential without being passivated. All sacrificial corrosion protection is effective for a long period of time. Also have excellent corrosion resistance.

 As described above, the plating of Zn—Cr alloy is practically excellent, but there is a problem of hexavalent chromium mist generated during plating, which hinders the health of plating workers and reduces air pollution. Environmental problems such as causing environmental problems are being highlighted. Therefore, there is an urgent need to develop and commercialize alternative metal materials with low environmental impact and high corrosion resistance.

 Patent document 1: Japanese Patent Application Laid-Open No. Sho 644-553997

 Patent Document 2: Japanese Patent Publication No. 2-5-1996

 Patent Literature 3: Japanese Patent Publication No. 3-2 949

<Disclosure of Invention>

 An object of the present invention is to provide a zinc-based alloy electroplating film having high corrosion resistance comparable to that of a Zn-Cr alloy coating without containing chromium, which has a large environmental load, and a metal material using the same. It is to be.

 The present inventors have conducted intensive studies to solve the above problems, and as a result, it has been found that corrosion resistance can be significantly improved by using zinc as a base material and a specific amount of iron group metal and tungsten as a plating film. They have found that they can do this and have completed the present invention. .

 Thus, the present invention provides (A) 30 to 96% by weight of zinc,

 (B) iron group metal 2 to 20% by weight, and

 (C) Tungsten 2 to 50% by weight

The present invention relates to a zinc-based alloy electroplating film having excellent corrosion resistance, characterized by comprising:

 The present invention also relates to a plated metal material having the zinc-based alloy electroplating film. BEST MODE FOR CARRYING OUT THE INVENTION>

The zinc alloy electroplating film of the present invention contains zinc (A), iron group metal (B) and tungsten (C) as essential components. From the viewpoint of corrosion resistance, the composition of the plating film is zinc (A) 30 to 96% by weight / ₀ , preferably 50 to 90% by weight, and iron group metal (B) 2 to 20% by weight, preferably -15% by weight, tungsten (C) 2-50% by weight, 3-2 °% by weight.

 Here, iron group metal (B) refers to iron, cobalt and nickel. Alloy coatings of zinc and iron group metals are generally known, but by further combining tungsten therewith, the corrosion resistance of the resulting alloy coatings is significantly improved. In particular, the use of iron as the iron group metal (B) has a great effect, and it is preferable to use iron. However, a system in which iron is used in combination with cobalt and / or nickel also has good corrosion resistance.

 The zinc-based alloy electroplating film of the present invention is prepared by using a plating solution containing Zn ions (a), iron group metal ions (b) and W ions (c), as described below, to form a steel strip or the like. The secondary molded product, which includes small parts such as bolts and press molded products, is stored in a perforated container, such as a rotatable barrel or a power wrench, by applying continuous electric plating to the next molded product. It is formed by plating.

"Zn ion (a)"

 Zn ion, which is a component (a) of the above plating solution, constitutes a main component of the plating layer.

 Zn ions are added to the plating bath in the form of chlorides, sulfates, fluorides, cyanides, oxides, organic acid salts, phosphates or simple metals.

"Iron group metal ion (b)"

 The iron group metal ion as the component (b) of the plating solution is selected from Ni ions, Co ions, and Fe ions.

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 or simple metal. "W ion (c)"

 W ions, which are component (c) of the above plating solution, are added to the plating bath in the form of a tungstic acid compound.

 Examples of the tandastanoic acid-based compound include tungstic acid, tandastenoate, phosphotungstic acid and phosphotungstate, and examples of the salt include ammonium salt, potassium salt, calcium salt, and sodium salt. Can be. Of these, sodium tungstate and ammonium tungstate are particularly preferred from the viewpoint of corrosion resistance.

"Plating solution"

 The above plating liquid includes metal ions other than the above (a), (b) and (c), for example,

Mg, Mn, Ti, Pb, Al, P and the like may be added.

 In addition, it is preferable to add a complexing agent to the plating solution so that metal ions can be stably present in the plating solution. Examples of the complexing agent include oxycarboxylates such as citrate, tartrate, and gluconate; aminoanoreconoles such as monoethanolamine, diethanolamine, and triethanolamine; ethylenediamine (ED A ), Polyamines such as diethylenetriamine and triethylenetetramine, aminocarboxylates such as ethylendiaminetetraacetate and nitroacetate, polyhydric alcohols such as sorbit and pentaerythritol, and mixtures thereof. Can be selected.

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

 As the above-mentioned corrosion-inhibiting pigment, generally known pigments can be used, and preferable examples thereof include phosphate, molybdate, metaborate, and silicate.

As the ceramic particles, for example, _{A 1 2 0 3, S i} 0 2, T i 0 2, Z r 0 2, Y 2 O 2, oxidation of such Th_〇 _{2, C e 0 2s F e} 2 0 3 _{things; B 4 C, S i C} , WC, Z r C, T i C, graphite, carbides such as graphite _{fluoride; BN, S i 3 N 4} , nitrides such as _{T i Ν; C r 3 B} 2, borides such as _{Z r B 2; 2 M g} O 'S I_〇 _2, M g O · S I_〇 _{2, Z r O 2 · S} i 0 2 silicate, etc., and the like. The mixing amount of the corrosion inhibiting pigment and / or the ceramic particles in the plating bath is preferably in the range of 5 to 500 g per liter. Ultra-fine particles of 1 m or less are preferred because smaller particles have better dispersion stability. The amount of eutectoid in the plating matrix is preferably in the range of 1 to 30% by weight, and more preferably 1 to 10% by weight, based on the total amount of precipitation. If the amount of eutectoid is small, the effect of improving the corrosion resistance is not exhibited, and if it exceeds 30% by weight, the coating film becomes brittle or the adhesion to the base material is reduced, which is problematic.

 In order to improve corrosion resistance, a corrosion inhibiting organic compound may be further added to the plating bath. Preferred corrosion inhibiting organic compounds include, for example, alkynes, alkynols, amines or salts thereof, thio compounds, aromatic carboxylic acid compounds or salts thereof, and heterocyclic compounds.

 Among these, alkynes are organic compounds containing a carbon-carbon triple bond, and include, for example, pentine, hexine, heptin, octin and the like.

 The alkynols are organic compounds having one or more hydroxyl groups in the alkynes, and include, for example, propargyl alcohol, 11-hexol 13-ol, 11-heptin 13-ol, and the like.

 Amines are organic compounds containing one or more nitrogen atoms in the molecule, and include both aliphatic and aromatic compounds. Examples of such amines include octylamine, nonylamine, decylamine, laurylamine, tridecylamine, cetylamine and the like.

 The 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, and thiourea.

A heterocyclic compound means an organic compound in which a ring molecule contains an atom other than carbon as a ring constituent element. Examples of such a heterocyclic compound include pyridine, benzothiazole, benzotriazole, and quinoline. , Indole, etc. No.

 Examples of the aromatic carboxylic acid compound include benzoic acid, salicylic acid, toluic acid, and naphthalene carboxylic acid.

 It should be noted that salts of amines and carboxylic acid compounds can be used, and the same effect can be obtained in this case. As the salt, in the case of amines, an acid addition salt such as a sulfate or a hydrochloride can be used. In the case of an aromatic carboxylic acid compound, a metal salt such as an alkali metal salt or a zinc salt or an ammonium salt can be used.

The amount of the corrosion inhibiting organic compound added to the plating bath is 0.1 to 10% by weight for alkynes and alkynols, and 3 to 10% by weight for amines or salts thereof. /. In addition, 0.2 to 5 weights for thio compounds. /. It is desirable to adjust the amount to 1 to 10% by weight for a heterocyclic compound and 3 to 8% by weight for an aromatic carboxylic acid compound or a salt thereof. By using such a plating bath with the addition of the corrosion inhibiting organic compound, it is possible to form a plating film having a C (carbon) content of 0.001 to 10% by weight on the metal material. measurement of carbon content in the plating film is a combustion method, for example, the organic matter is burned, by measuring the "C-S analysis apparatus" for measuring the absorbance in the infrared absorption band of the resulting co ₂ It is possible.

 In addition, the above-mentioned plating liquid can contain additives that are commonly used for the purpose of improving the coverage at high current densities and improving the throwing power at low current densities. Examples of these include a reaction product of amine and epihalohydrin, polyethylene polyamine, other quaternary amine polymers, urea, thiourea, gelatin, polybutyl alcohol, aldehyde, and the like.

 The above-mentioned plating bath composition is excellent in corrosion resistance and coating film adhesion by electroplating in the same manner as in the prior art, so that a coating film can be formed.

As bath conditions for electroplating, when the plating bath is a sulfuric acid bath, the pH is about 1 to 3, the bath temperature is about 30 to 80 ° C; when the chloride bath is, the pH is about 4 to 7; The temperature is about 10 to 50 ° C; the pH is preferably 12 or more in the case of an alkaline bath, the bath temperature is preferably about 10 to 50 ° C, and the plating film thickness is 0.5 to 1 in all cases. About 0 ιη is suitable. "Electric plating metal material"

 The metal material for electroplating of the present invention can be obtained by electroplating a metal material using the above electroplating liquid composition to form a plating film. Examples of the metal material include a material containing iron as a main component, for example, a material for a car, a home appliance, or a building material processed into a shape of a plate, a pipe, a joint, a clamp, a bolt, a nut, and the like.

 Electric plating conditions are as described above.

 Further, after the electroplating film is formed, a post-treatment is carried out with an acidic aqueous solution of a compound containing at least one element selected from the group consisting of cobalt, nickel, titanium and zirconium. The effect can be enhanced. 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, and chlorides of these metal elements. , Nitrate, sulfate, carbonate and the like can be used. Specifically, cobalt nitrate, zirconium oxynitrate, titanium hydrofluoric acid, zircon hydrofluoric acid, ammonium titanium hydrofluoride, zircon hydrofluoric acid Preferred are ammonium and the like. The acidic aqueous solution of the compound containing these metal elements preferably has a pH of 1 or more and less than 7, preferably 3 or more and 6 or less, such as hydrochloric acid, nitric acid, sulfuric acid, and hydrofluoric acid. The pH can be adjusted with an acid or an alkali such as sodium hydroxide, potassium hydroxide, and amines. If necessary, a complexing agent, silica particles, or the like may be added to the acidic aqueous solution. The addition amount of the compound containing a metal element is preferably from 0.001 to 5 mol 1 Z1, particularly preferably from 0.01 to: Lmol / 1.

 For the post-treatment with an acidic aqueous solution, for example, a metal material is immersed in a treatment solution having a bath temperature of 20 to 80 ° C., preferably 30 to 60 ° C. for 5 seconds or more, preferably 20 to 90 seconds. For example, it can be performed by bringing the electroplated film into contact with the treatment liquid.

The thus-obtained electroplated metal material is usually subjected to a surface treatment and, if necessary, a paint. The surface treatment is usually performed with a chromate-based surface treatment agent or a phosphate-based surface treatment agent. However, since the electroplated metal material of the present invention has excellent corrosion resistance, it can be used in combination with a chromium-free, environmentally friendly surface treatment agent. Also exhibits excellent corrosion resistance. In order to reduce the environmental burden, it is preferable to combine with a chromium-free environment-friendly surface treatment agent.

 The paint for applying to the metal material with an electric plating according to the present invention is not particularly limited, and any of a curing method such as a normal drying type, a heat curing type, and an active energy ray curing 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 electroplated metal material of the present invention is applied to an automobile, the electrodeposition coating, the intermediate coating, and the top coating are generally sequentially applied and baked after a phosphate treatment on the plating film. It is a target. Examples>

 Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. Hereinafter, “parts” and “%” are based on weight.

"1. Making electric steel plate"

 (Examples 1 to 18 and Comparative Examples 1 to 4)

 A cold-rolled steel sheet with a thickness of 0.8 mm and a size of 7 Omm X 15 Omm is alkali-degreased, washed with water, and then subjected to a predetermined metal ion, corrosion-inhibiting pigment, corrosion-inhibiting organic compound, The plating was performed in an acidic plating bath containing ceramic particles. The composition of the film was adjusted by changing the metal ion concentration ratio in the plating bath, the current density, and the bath temperature, and was controlled by appropriately selecting the plating film deposition time. Table 1 below shows the coating composition (wt%) and film thickness of the plating layers studied. The coating composition and film thickness of the plating layer were measured with a fluorescent X-ray analyzer SEA5200 (manufactured by Seiko Instruments Inc.).

 In addition, each metal ion used for the test was supplied from the following compound.

Z n; zn SO ₄ · 7H ₂ O

F e; F e so ₄ · 7H ₂ O

C o; co so ₄ · 7H ₂ o

N i; Ni SO ₄ · 7H ₂ o W; Na ₂ W0 ₄ · 2 H ₂ 0

The raw materials of notes (* 1) to (* 6) in Table 1 have the following contents, respectively. (* 1) A1: K-WH ITE 840 E, manufactured by Tika Co., Ltd., aluminum phosphate condensate.

 (* 2) A2: L F Boussie ZP—DL, manufactured by Kikuchi Color Co., Ltd., zinc phosphate type.

 (* 3) B 1: Fine particles, average particle size about 0.02 μm.

 (* 4) B 2: anoremina fine particles, average particle size about 0.01 μm.

 (* 5) C 1: 3-amino-1,2,4-triazole.

(* 6) C 2: Thiourea. "2. Paint 1J

 (Examples 19 to 36 and Comparative Examples 5 to 8)

After the surface of each electroplated steel sheet obtained in Table 1 above was alkali-degreased, the surface was adjusted (spray treatment using “Preparen Z” manufactured by Nippon Parti Rising Co., Ltd.), and further phosphate treatment (Nippon Part After spraying using “Pal Pond 3 1 18” manufactured by Riki Rising Co., Ltd., it is washed with water and dried to obtain a zinc phosphate-treated steel sheet (the adhesion of the treated film is 1.5 _§ πι ² ). Was.

 "Magicron 100 White" (Kansai Paint Co., Ltd., acryl-melamine resin paint, white) is applied to the zinc phosphate treated steel sheet obtained in this manner so that the dry film thickness becomes 30 μππι. It was applied and baked at 160 ° C. for 20 minutes to obtain a test coated plate.

 Various tests were performed on each of the obtained test coated plates based on the following test methods. The results are shown in Table 2 below.

 (Top coat adhesion): The test coated plate was immersed in boiling water at about 98 ° C for 2 hours, pulled up and left at room temperature for 2 hours. One scratch was placed in a grid pattern to create 100 square cells of 2 mm square. A cellophane adhesive tape was closely adhered to the cross section, 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 was observed at all.

 4: Peeling of the coating film is observed, but the peeling area is less than 10%.

 3: Peeling area is 10 /. Less than 25%.

 2: Peeling area is 25% or more and less than 50%.

 1: The peeling area is 50% or more.

(Corrosion resistance after painting): Put a crosscut that reaches the substrate on the test painted plate, perform a salt spray test for 240 hours in accordance with JISZ-2371, wash with water, dry, and adhere cellophane to the cross cut part. The maximum peeling width (one side, mm) from the cross cut portion when the tape was adhered and the tape was instantaneously peeled off was measured. 2

"3. Painting system 2"

 (Examples 37 to 54, Comparative Examples 9 to 12)

Wash each of the electroplated steel sheets obtained in Table 1 with hot water → degreasing (spray for 120 seconds at 43 ° C using an alkaline degreasing agent “FINE L-1460” manufactured by Nippon Perry Rising Co., Ltd.) → water washing → surface Adjustment (spray at room temperature for 30 seconds using titanium colloid-based surface conditioner “Preparen ZN” manufactured by Nippon Puriki Rising Co., Ltd.) → Zinc phosphate conversion treatment Use Balbon L-3020 ”and spray it at 43 ° C for 120 seconds. → Phosphate treatment by washing with water → Drying off with water. Then, cationic electrocoating paint“ Electron GT-10 ”(Kansai Paint Co., Ltd.) Made, epoxy polyester resin cation (Electrodeposition paint) was applied by electrodeposition and baked at 170 ° C for 30 minutes to obtain an electrodeposition coating plate with a dry film thickness of 20 µm. Amilac TP—65 gray, an intermediate coating on this electrodeposited surface

(Amino alkyd resin intermediate coating from Kansai Paint Co., Ltd.) was applied by spraying to a dry film thickness of 30 tm and baked at 140 ° C. for 30 minutes. After that, a top coat Neoamirac # 6000 White (Kansai Paint Co., Ltd., aminoalkyd resin top coat) is applied by spraying to a dry film thickness of 3 O / m and baked at 140 ° C for 20 minutes. Each test coated plate was obtained.

 Various tests were performed on each of the obtained test coated plates based on the following test methods. The results are shown in Table 3 below.

(Tibbing resistance): The test coated plate was fixed to a test piece holder of a stepping stone tester JA-400 (Tibbing tester manufactured by Suga Test Instruments Co., Ltd.) so as to be perpendicular to the stone spout. At 20 ° C, 50 g of granite No. 7 granite was sprayed onto the painted surface with 0.294MPs (3 kgf / cm ² ) compressed air, and the degree of scratching of the resulting coating film was visually observed. And evaluated according to the following criteria.

 ：: The size of the scratch is quite small, and the top coat is scratched.

 〇: The size of the scratch is small, and the intermediate coating film is exposed.

 Δ: The size of the flaw is small, but the base steel sheet is exposed.

 X: The size of the flaw is quite large, and the base steel plate is also largely exposed. (Water resistance secondary adhesion): The test coated plate was immersed in warm water at 40 ° C for 10 days, taken out and dried. 100 grids of 2 mm square were created in a grid pattern. A cellophane pressure-sensitive adhesive tape was adhered to the grid, and the peeled area of the coating film when the tape was instantaneously peeled off was evaluated according to the following criteria.

 5: No peeling of the coating film was observed at all.

 4: Peeling of the coating film is observed, but the peeling area is less than 10%.

 3: Peeling area is 10% or more and less than 25%.

 2: Peeling area is 25. /. Not less than 50%.

1: The peeled area is 50% or more. (Corrosion resistance): A cross cut that reaches the substrate is placed on the test coated plate, and this is subjected to a salt water spray test for 72 hours in accordance with JIS Z—2371, followed by washing with water, air drying, and rusting of general parts. The blisters were evaluated according to the following criteria, and the maximum peeling width (one side, mm) from the cross cut portion when a cellophane adhesive tape was adhered to the cross cut portion and immediately peeled off was measured.

 〇: No rust, blisters, etc. were observed on the painted surface.

 Δ: Rust, blisters, etc. were slightly observed on the coated surface.

 X: Rust, blisters, etc. are remarkably observed on the painted surface.

 (Salt water dip resistance): Put a cross cut that reaches the substrate on the test coated plate, immerse it in 5% saline at 50 ° C for 10 days, wash with water, air dry, and remove rust and blisters in the general part below. In addition to the evaluation based on the standard, the maximum peeling width (one side, mm) from the crosscut part when the cellophane adhesive tape was adhered to the crosscut part and immediately peeled off was measured.

 〇: No rust, blisters, etc. were observed on the painted surface.

 Δ: Rust, blisters, etc. were slightly observed on the coated surface.

X: Rust, blisters, etc. are remarkably observed on the painted surface.

Table 3

「4. Painting System 3」

 (Examples 55 to 72, Comparative Examples 13 to 16)

 After alkali-degreasing the surface of the plated steel sheet obtained in Table 1 above, a titanium-based undercoating agent prepared by the following process was applied on the surface using a bar coater so that the dry film thickness was 0.5 xm. Then, the substrate was heated for 10 seconds under the condition that the PMT (maximum temperature of the steel sheet) reached 100 ° C to prepare a ground-treated sheet. Then, add “∑:? Color 800”

“Primer” (modified epoxy resin paint, manufactured by Kansai Paint Co., Ltd.) is applied with a bar coater to a dry film thickness of 5 μm, and heated for 20 seconds at a PMT of 210 ° C for coating. Then, “? Color 1 580 White” (a polyester resin paint manufactured by Kansai Paint Co., Ltd.) is applied on the primer film by a bar coater so that the dry film thickness becomes 15 μπι. Heat for 40 seconds at 5 ° C Thus, each test coated plate having an upper layer coating film was prepared.

 For each of these test coated plates, the adhesion, corrosion resistance, and moisture resistance of the coating film were tested. Table 4 shows the test results. Each test was performed according to the following test methods.

 <Formulation of titanium base treating agent>

 Mix a mixture of 10 parts of tetra-iso-propoxytitanium and 10 parts of iso-propanol in a mixture of 10 parts of 30% hydrogen peroxide solution and 100 parts of deionized water at 20 ° C for 1 hour. Then, the mixture was aged at 25 ° C. for 2 hours to obtain a 2% titanium compound aqueous solution. By mixing 5 parts of 20% zircon hydrofluoric acid and 45 parts of deionized water with 50 parts of the obtained 2% aqueous titanium compound solution, a titanium base treating agent was obtained.

 (Adhesion of coating film): One hundred and one lmm-square cells were formed on the coating film surface of the test coated plate by making 11 scratches of length and width reaching the substrate with a knife in a grid pattern. The degree of peeling of the coating film when the cellophane adhesive tape was brought into close contact with the grid and the tape was instantaneously peeled off was evaluated according to the following criteria.

 5: No peeling of the coating film was observed at all.

 4: Peeling of the coating film is observed, but the peeling area is less than 10%.

 3: 25 when the peeled area is 10% or more. /. Less than.

 2: Peeling area is 25% or more and less than 50%.

 1: The peeling area is 50% or more.

 (Corrosion resistance): After sealing the end face and the back face of the test coated plate cut to a size of 7 O mm X 150 mm, a 4 T bent portion (with the coating surface outside) was placed on the top of the test coated plate. A part that is bent 180 degrees with four spacers of 8 mm thickness in between) is provided, and a cross-cut part is provided at the lower part of the test coated plate. The test coated plate is stipulated in JISZ-2371 The salt spray test was performed for 1000 hours. On the test coated plate after the test, the degree of whitening at the 4T bent part, the blister width at the cross cut part, and the degree of blistering at the general part (the part without processing and cutting) were evaluated according to the following criteria.

 General part:

· ：: No blistering is observed. 〇: Blistering is slightly observed.

 Δ: Blistering is considerably observed.

 X: Swelling is remarkable, and peeling of the coating film is partially observed.

 Crosscut part:

 ◎: The width of one side bulge from the cross cut is less than 1 mm. ,

 〇: The width of one side bulge from the cross cut is 1 mm or more and less than 2 mm.

 △: One side blister width from cross cut is 2 mm or more and less than 5 mm.

 X: The cross-cut collar has a blister width of 5 mm or more on one side.

 4 T bending part:

 ：: No white 鲭 was observed.

 〇: Whitening is slightly observed.

 Δ: White spots are considerably observed.

 X: Whitening is remarkable, and peeling of the coating film is partially observed.

 (Moisture resistance): After sealing the end face and the back face of the test coated plate cut into a size of 7 O mm X 150 mm, perform the test according to JIS-540 9.2.2. Was. The test time was 100 hours under the condition that the temperature in the moisture resistance tester pox was 50 ° C and the relative humidity was 95 to 100%. The degree of blistering of the coating film on the test coated plate after the test was evaluated according to the following criteria.

 ：: No blistering was observed.

 〇: Blistering is slightly observed.

 Δ: Blistering is considerably observed.

X: Swelling is remarkable, and peeling of the coating film is partially observed. Table 4

"5. Painting 4 J

 (Examples 73 to 90 and Comparative Examples 17 to 20)

 After the steel bolts were degreased with alkali and washed with water, they were immersed in a 1% sulfuric acid solution at room temperature for 30 seconds to perform activation treatment. Thereafter, using a batch-type barrel plating apparatus, plating was performed in an alkaline plating bath containing predetermined metal ions, a corrosion-inhibiting pigment, a corrosion-inhibiting organic compound, and ceramic particles shown in Table 1. The composition of the film was adjusted by changing the metal ion concentration ratio in the plating bath, the current density, and the bath temperature, and the plating film thickness was controlled by appropriately selecting the plating time. afterwards,

HN0 ₃ 5 g / ⁷ 1 and (NH ₄₎ 5 to ₂ Z r F ₆ 15 g consisting of Z 1 acidic aqueous solution

Post-treatment was performed by immersion at 0 ° C for 30 seconds to prepare a test bolt, and the corrosion resistance was evaluated by the following method. Table 5 shows the evaluation results. (Corrosion resistance): A salt spray test (SST) was carried out in accordance with JISZ 2371, and the corrosion resistance was evaluated based on the occurrence time of white 10% and red 5%. Table 5

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

 This application is based on a Japanese patent application filed on Dec. 9, 2003 (Japanese Patent Application No. 2003-410746), the contents of which are incorporated herein by reference.

<Industrial applicability>

The zinc-based alloy electroplating film of the present invention is obtained by adding a specific amount of iron group metal and tungsten to zinc. The metal material having remarkably improved corrosion resistance and having the zinc-based alloy electroplating film is particularly useful as a metal member for automobiles.

Claims

The scope of the claims

1. (A) Zinc 30-96% by weight,

 (B) Iron group metal 2 to 20% by weight, and

 (C) Tungsten 2-50% by weight

A zinc-based alloy electroplated film having excellent corrosion resistance, characterized by containing.

2. The zinc-based alloy electroplating film according to claim 1, wherein the iron group metal (B) is iron.

3. The zinc-based alloy electroplating film according to claim 1 or 2, further comprising 1 to 30% by weight of the corrosion-inhibiting pigment and / or ceramic particles in the plating film.

4. The zinc-based alloy electrocoating film according to claim 3, wherein the corrosion-inhibiting pigment is at least one selected from the group consisting of phosphate, molybdate, metaborate and silicate.

5. ceramic particles, A 1 ₂ 0 _3, S I_〇 _2, T I_〇 _2, Z R_〇 _2, Y ₂ 0 _2, Th_〇 _2, C E_〇 _{2, F e 2 O 3,} B 4 C , S i C, WC, Z r C, T i C, black tin, graphite _{fluoride, BN, S i 3 N 4} , T i N, C r 3 B 2, Z r B 2, 2Mg O · S i 4. The zinc-based alloy electroplating film according to claim 3, wherein the film is at least one kind of particles selected from the group consisting of 0 ₂ Mg O ■ S i O ₂ , and Z r O ₂ · S i O ₂ .

6. In addition, at least one organic compound selected from the group consisting of alkynes, alkynols, amines or salts thereof, thio compounds, aromatic carboxylic acid compounds or salts thereof, and heterocyclic compounds is attached to the coating film. The zinc-based alloy electroplating film according to any one of claims 1 to 5, which contains 0.001 to 10% by weight as a C (carbon) content.

7. A plated metal material comprising the zinc-based alloy electroplated film according to any one of claims 1 to 6.

8. After the zinc-based alloy electroplating film according to any one of claims 1 to 6 is formed on the metal material, at least one selected from the group consisting of cobalt, nickel, titanium, and zirconium. A plating metal material which is brought into contact with an acidic aqueous solution of a compound containing an element.