JP2002105688A - Electrogalvanized metallic sheet and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Zn-X based electroplated metallic sheet having excellent corrosion resistance and excellent productivity and containing a metallic element X in which hydrogen generating potential is baser than the ordinary hydrogen generating potential in water based electroplating and also nobler than -2.363 V and to provide a production method by which the same plate is electrodeposited from the metallic salt of the metallic element X in an aqueous solution. SOLUTION: This Zn-X based electroplated metallic sheet is obtained by forming, on at least either surface of a metallic base material, a Zn-X based electroplated layer essentially consisting of Zn and containing the metallic element X, particularly, a Zn-Al based or Zn-Ti based electroplated layer. In the case C is contained in the Zn-X based electroplated layer, far superior corrosion resistance can be obtained. The Zn-X based electroplated metallic sheet can be produced by performing electroplating using an acidic aqueous solution containing Zn and the metallic salt of the metallic element X and further containing an additive for suppressing the generation of hydrogen, particularly, containing a surfactant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a standard electrode potential
Normal hydrogen generation potential in aqueous electroplating (-1.185
The present invention relates to a Zn-based electroplated metal sheet containing a metal element which is less noble and noble than -2.363 V, and a method for producing the same. More particularly, it is suitable in the fields of building materials, household appliances, automobiles and the like. The present invention relates to a Zn-based electroplated metal sheet having excellent corrosion resistance and a method for producing the same. In the present invention, the metal substrate to be plated includes Fe or Fe.
In addition to the base alloy, it includes non-ferrous metals such as Cu, Al and Ti and their alloys, and their shapes are not limited to flat materials, corrugated materials, pipes, bars, wires, etc. The present invention will be described with reference to a typical steel plate as a base material.

[0002]

2. Description of the Related Art In a wide range of fields, such as building materials, household appliances and automobiles, Zn-based plating is widely used as a means of preventing corrosion of steel sheets and the like. A plating method and a vapor deposition plating method are generally employed. By the way, various types of Zn-based plated steel sheets have been developed so far, but Zn-based electroplated metal sheets containing a metal element whose standard electrode potential is lower than the hydrogen generation potential generate hydrogen in water-based electroplating. Since it occurs preferentially and the metal element does not precipitate from the metal salt contained in the bath, it is mainly produced by a hot-dip plating method or a vapor deposition plating method.

[0003] However, the vapor deposition plating method requires a huge vacuum facility or the like, and therefore has problems such as a remarkably high production cost as compared with other plating methods, and complicated maintenance of the vacuum chamber.

In the hot-dip plating method, since the plating bath needs to be heated to a temperature higher than the melting point of the Zn-based plating material, a relatively thick oxide film is formed on the plating surface, which is limited by the mechanical properties of the substrate to be plated. Are generated, thereby deteriorating the chemical conversion property. Further, there are also problems such as difficulty in thinning, and poor appearance due to non-plating or dross.

[0005] On the other hand, as described above, it is difficult to deposit the metal element from the metal salt even if an attempt is made to adopt a normal aqueous electroplating method. Research has been conducted on a method of dispersing Al powder in a Zn plating bath and eutectoid during electroplating, and a non-aqueous electroplating method using an organic solvent or a molten salt. However, both have difficulties in bath management,
Due to operational problems, it has not been established as a general-purpose electroplating technology.

Therefore, if a Zn-based electroplating containing a metal element whose standard electrode potential is lower than the hydrogen generation potential can be obtained from the metal salt in the bath by using a water-based electroplating method, the plating solution By appropriately controlling the amount and ratio of desired metal ions, overvoltage (cathode current density), amount of current, and the like included in the plating layer, the component composition and the amount of adhesion of the plating layer can be easily changed. Also, the consumed metal ions are
It can be supplied as a solution containing desired metal ions from outside the system, does not require special equipment as compared with existing electric Zn plating equipment, and is suitable for continuous production on an industrial scale. On the other hand, since there is no high temperature part during the electroplating process, the applicable range of the substrate to be plated is also expanded, a thick oxide film is not generated on the surface, and the chemical conversion property is improved, Further, the uniformity of the appearance is improved.

As described above, by using the aqueous electroplating method, the standard electrode potential is lower than the hydrogen generation potential, and
There has been a demand for the development of a method for obtaining a Zn-based electroplated metal sheet containing a metal element which is nobler than -2.363 V from the metal salt in the bath.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has excellent corrosion resistance and excellent productivity. The standard electrode potential is lower than the hydrogen generation potential, and- It is an object of the present invention to provide a Zn-based electroplated metal sheet containing a metal element that is nobler than 2.363 V from the metal salt in a bath and a method for producing the same.

[0009]

The Zn-based electroplated metal plate of the present invention, which has solved the above-mentioned problems, is characterized in that at least one surface of a metal substrate has a Zn-based standard and a standard hydrogen-based electrode measured based on a standard hydrogen electrode. Electrode potential (temperature 25 ° C) is -1.185 V
It is more noble and more noble than -2.363V, that is, contains a metal element X (the metal X is represented by Al or Ti) which satisfies -2.363V and -1.185V or less. The gist is that a Zn-X-based electroplating layer is formed. Further, a component containing C as a constituent element in the Zn-X-based electroplating layer (hereinafter, abbreviated as C component).
(Preferably an organic compound) is desirable because the corrosion resistance is greatly improved.

[0010] The content of the metal element X in the Zn-X-based electroplating layer is preferably 0.05 to 60% (meaning by mass, the same applies hereinafter).
The component content is desirably 0.01 to 15% in terms of C element.

[0011] The method for producing a Zn-X-based electroplated metal plate of the present invention which has solved the above-mentioned problems includes a standard electrode potential (temperature) measured with reference to a metal salt of Zn and a standard hydrogen electrode.
25 ° C.) contains a metal salt of a metal element X represented by Al or Ti, which is lower than −1.185 V and more noble than −2.363 V, and further represented by a surfactant. It is an object of the present invention to perform electroplating using an acidic aqueous solution containing an additive that suppresses the generation of hydrogen during electroplating.

The surfactant is preferably a nonionic or cationic surfactant, and the concentration in the acidic aqueous solution is preferably 0.01 to 30 g / L.

As the nonionic surfactant, it is recommended to use at least one selected from the group consisting of polyethylene glycol, polyoxyethylene alkyl ether, and polyoxyethylene polyoxypropylene alkyl ether. As the agent, it is preferable to use one or more selected from the group consisting of primary amines, secondary amines, tertiary amines, quaternary ammonium salts and heterocyclic compounds, and in particular, cationic surfactants In this case, it is desirable to have at least one benzene ring.

Further, in the method of the present invention, electroplating is performed by 3
It may be performed at a current density of 0 to 1500 A / dm ² .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electroplating method using water as a solvent is widely used as a plating solution at present and contains a metal element whose standard electrode potential is lower than the hydrogen generation potential from metal salts in the bath. Even when attempting to obtain Zn-based electroplating, since the potential is lower than the hydrogen generation potential due to the electrolysis of water as a solvent, almost all of the input energy is consumed in the hydrogen generation reaction, and the metal element is charged with electricity. Cannot be analyzed.

However, the standard electrode potential (temperature: 25 ° C.) measured by the present inventors from the metal salt in the aqueous solution, particularly with reference to the standard hydrogen electrode, is lower than -1.185 V, and
As a result of intensive research on a method for obtaining a Zn-X-based electroplating containing a metal element noble than -2.363V, in addition to Zn and a metal salt of the metal element X, a specific organic compound (nonionic or cationic (Surfactant), the present inventors have found that a Zn-X-based plating layer can be formed by an electroplating method, and arrived at the present invention. Furthermore, the Zn-X-based electroplating layer formed by the electroplating method according to the present invention contains a C component originating from the organic compound present in the electrolytic solution as a third element. Due to the presence of the C component, the Zn-X-based electroplated layer of the present invention
It was also found out that the Zn-X binary alloy plating layer obtained by a normal hot-dip plating method exhibited much better corrosion resistance.

The term "corrosion resistance" used herein refers to the resistance to red rust and pitting corrosion as-plated (unpainted), or to the corrosion resistance and corrosion resistance at the end of a coated steel sheet having scratches or a coated steel sheet. Indicates the swelling property of the coating film.

The metal element X according to the present invention, in which the standard electrode potential is lower than the hydrogen generation potential, means that the standard electrode potential measured at 25 ° C. with reference to the standard hydrogen electrode is lower than −1.185 V, and , -2.363V. At around -1.185 V, when electroplating from an aqueous solution, the generation of hydrogen due to the electrolysis of water is substantially remarkable. On the other hand, if the voltage is lower than -2.363 V, it becomes practically impossible to flow a current for lowering the potential in electroplating from an aqueous solution. As the metal element X, specifically, A
l, Ti, Zr, etc. are conceivable.
l and Ti are preferably used.

The composition of the Zn—X—C-based electroplating layer of the present invention is as follows. If the amount of the metal element X is too small, the effect of adding the metal element X is not substantially exerted. Since no particular difference from the plating layer of Zn is recognized, it is desirable to contain 0.05% or more,
More preferably, it is 0.2% or more. On the other hand, the metal element X
If the amount is too large, the chemical conversion property deteriorates, so the content is preferably 60% or less, and more preferably 30% or less.
% Is more desirable. The reason why the chemical conversion property decreases when the content of the metal element X is increased is that the metal element whose standard electrode potential is lower than the hydrogen generation potential easily forms a strong oxide film, and the reactivity of the plating surface is reduced. It is presumed that this is due to a decrease.

Next, the content of the C component is 0.01 in terms of C element.
%, The effect of the addition of the C component is not substantially recognized, and there is no particular difference in corrosion resistance from ordinary Zn-X binary alloy plating. Therefore, 0.01% or more is desirable. More preferably, it is 0.05% or more.
On the other hand, when the content of the C component exceeds 15%, the plating appearance becomes discolored black and powdery precipitates are formed, a so-called “plating burn” phenomenon occurs, and the commercial value is significantly impaired, and the plating adhesion is also reduced. Therefore, it is necessary to be 15% or less, preferably 10% or less, and more preferably 8% or less.

In measuring the content of the C component, a well-known combustion infrared absorption method, a fluorescent X-ray analysis method, or the like may be used. By dissolving in a solution (preferably about 3 to 10%) or the like and measuring the amount of carbon contained in the solution, the C component content in the plating layer can be measured. The latter X-ray fluorescence spectrometry can be measured nondestructively. However, when a steel sheet is used as a base material, it is necessary to correct the influence of the C component contained in the steel sheet, and in view of measurement sensitivity. Therefore, it is recommended to use the combustion infrared absorption method.

As described above, in the present invention, the metal element X
Due to the combined effect of C and C, very excellent corrosion resistance that cannot be achieved by adding each alone can be obtained.

The constituent elements of the plating layer other than the metal elements X and C may be mainly Zn, but the workability, the paintability, the chemical conversion property, the weldability, the blackening resistance and the further improvement of the corrosion resistance are improved. From the viewpoints of Ni, Co, Fe, Mn
Standard electrode potential measured at 25 ° C. with reference to a standard hydrogen electrode, various metal elements having a nobleness of −1.185 V or oxides such as SiO ₂ and Al ₂ O ₃ may be used alone or in combination. And may be eutectoid.

The Zn-XC-based electroplating according to the present invention
Although the amount of coating is not particularly limited,
2 g / m^TwoIf less than
2g / m2 because of insufficient corrosion resistance^TwoAnd above
Preferably 5 g / m^TwoThat is more desirable
New 100 g / m^TwoWith high coating weight
Causes problems in moldability and spot weldability,
100 g / m^TwoMust be
Essential, 60g / m^TwoThe following is desirable, and 40 g / m ^TwoLess than
Below is more desirable. In addition, plating is
It only needs to be applied to the required side of the metal plate,
May be applied to both sides.

In the present invention, since the coating is excellent in corrosion resistance and the like, the finish coating can be omitted and the coating can be used as it is, but the surface of the plated metal material has the corrosion resistance, scratch resistance, Of course, various chemical treatments and coatings can be applied in order to further improve various performances such as fingerprint resistance and workability. Specific examples of such a chemical conversion treatment include a chromate film treatment, a phosphate film treatment, a clear film treatment and the like.

Among these, typical examples of the chromate film treatment include a reaction type chromate film treatment, a coating type chromate treatment, and an electrolytic chromate treatment, which are mainly composed of a Cr compound and have corrosion resistance, scratch resistance, and black resistance. Various oxides such as silica and organic silane compounds, as well as phosphoric acid, nitric acid, fluoride,
It is preferable to perform a chromate treatment containing various reaction accelerators such as silicon fluoride.

Further, regarding the thin film clear film treatment,
When the coating is mainly composed of an organic resin, an epoxy resin, a polyester resin, a polyurethane resin, an ethylene copolymer resin containing an ethylenically unsaturated carboxylic acid as a polymerization component, a polyvinyl resin, a polyamide resin ,
What is necessary is just to apply a substance mainly composed of an organic resin component such as a fluorine-based resin, or to the quality such as corrosion resistance, lubricity, scratch resistance, workability, weldability, electrodeposition coating property, coating film adhesion, etc. If necessary, various oxide particles such as silica, inorganic pigments such as various phosphates, and wax particles,
Application of a treatment liquid containing an organic silane compound, a naphthenate or the like is exemplified.

When the film is mainly composed of an inorganic substance, a film mainly composed of a silicate such as sodium silicate, potassium silicate, lithium silicate or the like may be applied. In order to improve the quality such as corrosion resistance, lubricity, scratch resistance, workability, weldability, electrodeposition coating property, coating film adhesion, etc., various kinds of oxide particles such as colloidal silica and various phosphoric acids For example, a treatment liquid containing an inorganic pigment, wax particles, and an organic silane compound is applied.

The above chemical conversion coatings may be formed alone or in various combinations according to the purpose. The preferable amount of the chemical conversion coating film is 5 to 300 m in consideration of the economical efficiency and the effect of improving the corrosion resistance.
It is generally selected from the range of g / m ² , and the preferable amount of the inorganic or organic coating is generally in the range of 0.05 to 20 μm in terms of the same reason as described above.

The base material used for the surface-treated plate of the present invention is:
Various cold-rolled steel sheets used as materials for automobiles, home appliances, building materials, and the like are mainly used. However, it is also possible to select a metal plate other than a steel plate such as a hot-rolled steel plate or an aluminum plate depending on the use.

Next, the method for producing Zn-XC-based electroplating of the present invention will be described in detail. Forming a Zn-X-based plating film by an electroplating method is as follows: a plating solution using water as a solvent, a metal salt of Zn, and a standard electrode potential measured based on a standard hydrogen electrode at a temperature of 25 ° C. -1.1
An additive that suppresses hydrogen generation, together with a metal salt of a metal element X that is less noble than 85 V and nobler than -2.363 V, that is, more than -2.363 V and less than 1.185 V, especially nonionic Alternatively, it can be realized by adding a cationic surfactant. The surfactant is indispensable for electrodepositing the metal element X, and is electrodeposited on the plating layer together with the metals to exhibit the excellent corrosion resistance of the present invention.

By adding a surfactant to the plating solution,
The reason why the metal element X has been electrodeposited, which has been said to be impossible to electrodeposit, has been elucidated at present, but it is probably due to the following reasons. That is,
The added surfactant interferes with the electrolysis reaction of water (the surfactant adsorbed on the cathode surface causes a reduction process of hydrogen ions) and greatly polarizes the overpotential for hydrogen generation. It is estimated that the electrodeposition potential of element X has been reached.

Nonionic and cationic surfactants include
They may be added alone or in various mixtures. Regardless of the surfactant, the content in the plating solution is 0.01 g /
If the content is less than L, the content of the metal element X and the content of the C component in the plating layer of the present invention cannot be achieved, so that the content needs to be 0.01 g / L or more, and 0.1 g / L or more.
/ L or more, more preferably 0.4 g / L or more. On the other hand, even if it is added in excess of 30 g / L, the electrodeposition effect of the metal element X saturates, and the plating burn phenomenon occurs. Therefore, the content needs to be 30 g / L or less. Preferably, 15g /
L or less is more preferable.

The surfactant of the present invention may be a nonionic or a surfactant.
Although it is not particularly limited as long as it is a cationic type, for example,
For example, polyethylene glyco having a molecular weight of 200 to 20,000
, RO (CH_TwoCH_TwoO)_nH (however, R: C₈H₁₇,
C₉H₁₉, N: 2 to 30)
Alkylphenyl ether, RO (CH_TwoCH_TwoO) _n
H (however, n: 4 to 30)
Tylene alkyl ether, RO (CH_TwoC_TwoH_FourO)_n(C
_ThreeH₆O)_mH, HO (C_TwoH_FourO)_n(C_ThreeH₆O) _m(C_TwoH
_FourO)_lH (however, n, m, l: 5-200) polyoxo
Such as ethylene polyoxypropylene alkyl ether
Preferred as a nonionic surfactant.

Similarly, as the cationic surfactant, primary amines, secondary amines, tertiary amines, quaternary ammonium salts and heterocyclic compounds are applicable. Examples of the primary amines include ethylamine represented by R-NH _2, propylamine, aliphatic primary amine or aniline and dodecyl amine, 0-toluidine, m- toluidine, benzyl aniline, alpha-naphthylamine, beta- An aromatic amine such as naphthylamine can be exemplified. Examples of the secondary amine include aliphatic secondary amines such as dimethylamine, diethylamine, dipropylamine and diisopropylamine represented by R—NH—R, and methylaniline, ethylaniline, dibenzylaniline, diphenylamine and the like. Can be exemplified. Examples of the tertiary amine include aliphatic tertiary amines represented by RRRN such as trimethylamine, triethylamine, tripropylamine, tributylamine, and triamylamine, and methylaniline, diethylaniline, tribenzylamine, and trianiline. Examples thereof include aromatic amines such as phenylamine and dimethylbenzylamine. Examples of the heterocyclic compound include those containing one nitrogen atom such as 5-membered pyrrole and thiazole; and those containing 2 nitrogen atoms such as imidazole, pyrimidine and thymine, such as 6-membered pyridine. Contains three nitrogen atoms such as triazole; Indole, quinoline, mercaptobenzimidazole, mercaptobenzoxazole, benzothiazole, benzotriazole, etc., in which these heterocycles are fused with a benzene ring; Azabicycloheptane; polycyclic compounds such as hexamethylenetetramine; or derivatives thereof. Alternatively, a quaternary ammonium salt obtained by reacting the above tertiary amine with an alkyl halide or the like, for example, alkyltrimethylammonium halide such as stearyltrimethylammonium chloride, stearyltrimethylammonium bromide, lauryltrimethylammonium chloride, chloride, etc. Alkyldimethylbenzylammonium salts such as lauryldimethylbenzylammonium and stearyldimethylbenzylammonium chloride; alkyltri (polyoxyethylene) ammonium halides such as tripentaoxyethylenestearylammonium chloride and tripentaoxyethylenelaurylammonium chloride; A quaternized compound obtained by reacting an alkyl halide or the like with a formula compound, for example, pyridinium chloride Halogenated pyridinium etc., it is possible to use also halogenated alkyl pyridinium such as butyl chloride picolinium chloride. Among the above-mentioned cationic surfactants, those containing one or more benzene rings in the structure thereof are more preferable.

For the plating solution, an acidic bath (for example, a sulfate bath or a chloride bath) can be used. As for Zn and the metal element X, an amount of a desired plating film composition as metal ions such as sulfate, chloride, acetate and carbonate may be added to the plating solution. Further, the pH of the plating solution is not particularly limited, but the pH is 0.0 to 0.0 from the relationship between the current efficiency and the plating burn phenomenon.
It is preferably in the range of 2.0. In order to increase the conductivity and reduce the power consumption, the plating solution contains Na
There is no problem even if a conductive auxiliary such as ₂ SO ₄ , (NH ₄ ) ₂ SO ₄ , KCl, or NaCl is added.

Regarding the plating conditions, in particular, the cathode current density (hereinafter simply referred to as the current density) is set to 30 to 1500 A.
/ Dm ² . Since changing the current density means changing the cathode surface potential,
Controlling the current density to an appropriate value and bringing the cathode surface potential closer to the electrodeposition potential of the metal element X is in accordance with the spirit of the present invention. That is, when the current density is less than 30 A / dm ^{2, the} predetermined metal element X cannot be electrodeposited even when the nonionic or / and cationic surfactant of the present invention is added. Conversely, if it exceeds 1500 A / dm ² , the supply speed of the metal ions to the cathode surface is likely to be delayed, and the plating burn phenomenon is likely to occur. at the same time,
Since the plating voltage is increased and the power consumption is increased, the economy is poor. Therefore, preferably 50 to 1000 A / d
m ² , more preferably 100 to 800 A / dm ² .

Other plating conditions such as plating solution temperature and relative flow rate are not particularly limited.
It can be changed appropriately within a range where defects such as plating burnout do not occur. For example, the effect of the present invention was confirmed at 30 to 70 ° C. for the former and 0.3 to 5 m / s for the latter. Note that the relative flow velocity is a difference between the liquid flow velocity and the passing speed in consideration of the flow direction of the liquid and the passing direction of the steel plate as the plating original plate.

There is no particular limitation on the plating method. The plating base material may be subjected to a pretreatment such as degreasing or pickling according to a conventional method, and then subjected to electroplating in a vertical or horizontal plating cell. As the electroplating method, a known method such as a direct current (constant current) plating method or a pulse plating method may be employed.

Since the method of the present invention employs an electroplating method using an aqueous solution, there is no portion that becomes high temperature (at most the boiling point of water) during the process. As such an electroplated metal plate, those having various mechanical properties can be used. Further, in the method of the present invention, since the metal element X exists as an ion in the aqueous solution, the ion ratio of Zn / X can be easily changed, and accordingly, the content of the metal element X in the plating layer can be arbitrarily adjusted. And the consumed metal ions can be easily replenished with an aqueous solution.

Hereinafter, the structure, operation, and effects of the present invention will be described in detail with reference to examples. However, these do not limit the present invention in any way, and may be appropriately changed and implemented without departing from the spirit of the present invention. This is all included in the technical category of the present invention.

[0042]

EXAMPLE 1 An Al-killed cold-rolled steel sheet produced by a conventional method was used as a base material for plating. This was degreased and pickled, and then electroplated using a sulfate bath under the following conditions. In the plating solution, lauryldimethylbenzylammonium chloride (Catinal CB-50 manufactured by Toho Chemical Industry) was used as a cationic surfactant.
Was added at the concentrations shown in Table 1. <Electroplating Conditions> plating solution _{composition: ZnSO 4 · 7H 2 O 50~400g} / L Al 2 (SO 4) 3 · 14~18H 2 O 50~400g / L Na 2 SO 4 20~100g / L H 2 SO ₄ 10-70 g / L ・ Current density: 20-2000 A / dm ²・ Plating bath temperature: 60 ± 5 ° C. ・ Plating solution flow rate: 0.5-5 m / sec ・ Electrode (anode): IrO _x electrode ・ Plating adhesion Amount: 30 g / m ²

For comparison, a sample without the organic compound of the present invention and a hot-dip plating method
An n-Al binary alloy plating was produced.

The uncoated (as-plated) corrosion resistance of the obtained plated steel sheet was evaluated by a JIS Z2371 salt water spray test. The area ratio of red rust occurrence 96 hours after the salt spray test was determined according to the following criteria. Table 1 summarizes the obtained results. [Corrosion Resistance Evaluation Criteria]: 0%: less than 10%: 10 or more and less than 50% ×: 50% or more

[0045]

[Table 1]

As is clear from Table 1, in the case of Example No. 1 containing Al and C in the plating layer within the scope of the present invention. 1 to 23
Shows excellent corrosion resistance. On the other hand, in Comparative Example No. where the content of Al or C in the plating layer was out of the range of the present invention. Nos. 24 to 27 are inferior in corrosion resistance. Above all, Comparative Example No. in which the cationic surfactant of the present invention was not added. No. 26 could not electrodeposit Al at all.

Further, No. The Zn-Al alloy plating of the conventional example produced by the hot-dip plating method shown in Nos. 28 to 30 does not contain the C component in the plating layer at all, but has the same Al content in the plating layer.
In Example No. of the present invention, Corrosion resistance is inferior as compared with 5, 6, and 12.

Example 2 Various surfactants shown in Table 2 were added to a plating solution, and Zn-
A Ti-C electroplated steel sheet was produced. The base material and various plating conditions were the same as in Example 1, except that the plating solution composition described below was used. <Electroplating Conditions> plating solution _{composition: ZnSO 4 · 7H 2 O 50~400g} / L Ti (SO 4) 2 50~400g / L H 2 SO 4 50~200g / L

The corrosion resistance of the obtained plated steel sheet was evaluated in the same manner as in Example 1. The results are also shown in Table 2.

[0050]

[Table 2]

As is clear from Table 2, Example No. 1 of the present invention using the nonionic or cationic surfactant of the present invention.
Any of 31 to 43 can precipitate Ti,
Excellent corrosion resistance. On the other hand, Comparative Example No. 1 using an anionic surfactant was used. In the case of No. 44 to 45, Ti could not be precipitated, so that excellent corrosion resistance could not be obtained.

[0052]

According to the present invention, the standard electrode potential, which is excellent in corrosion resistance and productivity as well as the productivity, is the normal hydrogen generation potential (-1.185V) in aqueous electroplating. (Before and after) a Zn-X-based electroplated metal plate containing a metal element X which is more base and noble than -2.363V, and which can be electrodeposited from a metal salt of the metal element X in an aqueous solution The production method can be provided.
In particular, the plated metal sheet of the present invention has excellent corrosion resistance not found in conventional surface-treated metal materials. Furthermore, the composition ratio of the plating film and the coating weight can be easily controlled, and the replenishment method of various metal ions is easy. The degree of freedom of characteristics is also widened, and it can be manufactured at lower cost than Zn-X based alloy plating by vapor deposition plating or the like.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukihisa Komiya 1 Kanazawacho, Kakogawa City, Hyogo Prefecture Inside the Kakogawa Works, Kobe Steel Co., Ltd. No.19 F-term (reference) in Kobe Steel, Ltd. Thin Plate Product Technology Dept. 4K023 AB29 BA06 CA01 CB11 CB19 CB28 CB33 4K024 AA17 AB01 BA03 BB15 BB18 BC01 CA02 GA04

Claims (9)

[Claims] 1. A standard electrode potential (at a temperature of 25 ° C.) measured on the surface of a metal substrate with Zn as a main component and a standard hydrogen electrode as a reference.
℃) is more than -2.363V and -1.185V or less metal element X
A Zn-X-based electroplated metal plate comprising a Zn-X-based electroplated layer containing: 2. The method according to claim 1, wherein the metal element X is Al or T
The Zn-X-based electroplated metal sheet according to claim 1, wherein i is i. 3. The Zn—X-based electroplated metal sheet according to claim 1, wherein a component containing C as a constituent element is present in the Zn—X-based electroplated layer. 4. The Zn—X-based electroplated metal sheet according to claim 3, wherein the component containing C as an element is an organic compound. 5. The content of a component containing C as a constituent element in the Zn—X-based electroplating layer is 0.04 in terms of C element.
The Zn- content according to claim 3 or 4, which is 1 to 15% by mass.
X-based electroplated metal plate. 6. The metal element X content in the Zn—X based electroplating layer is 0.05 to 60% by mass.
The Zn-X-based electroplated metal plate according to any one of the above. 7. A standard electrode potential (temperature: 25 ° C.) measured based on a metal salt of Zn and a standard hydrogen electrode is -2.363.
Electroplating is performed using an acidic aqueous solution containing a metal salt of a metal element X satisfying a value exceeding V and not more than-1.185 V and further suppressing the generation of hydrogen during electroplating. Of producing a Zn-X-based electroplated metal sheet. 8. The method for producing a Zn—X-based electroplated metal sheet according to claim 7, wherein the additive that suppresses hydrogen generation is a surfactant. 9. The method for producing a Zn—X-based electroplated metal sheet according to claim 7, wherein the metal element X is Al or Ti.