JP2003193268A - Surface treated steel sheet having excellent corrosion resistance and blacking resistance and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treated steel sheet using a galvanized steel sheet as a base material and having excellent corrosion resistance and blackening resistance. <P>SOLUTION: The surface treated steel sheet has a reaction layer of zinc with S or a S-adsorbing layer in which the deposited quantity of S is 0.010-100 mg/m<SP>2</SP>on a plated film surface layer of the galvanized steel sheet and a chemical conversion layer, preferably a chemical conversion layer formed by a cathode electrolytic treatment and containing a vanadic compound and silica thereon. Because zinc in the reaction layer of zinc with S or the S-adsorbing layer formed on the plated film surface layer is in an oxidized state, additional oxidation and the production of zinc oxide are suppressed to improve the blacking resistance and further the corrosion reaction is suppressed to improve the corrosion resistance as the result of that the reaction layer of zinc with S or the S-adsorbing layer suppress the oxidation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated steel sheet having excellent corrosion resistance and blackening resistance suitable for use in automobiles, home appliances, building materials and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Zinc-based plated steel sheets have a drawback that they turn black in a humid environment. This black discoloration phenomenon is a phenomenon in which the galvanized surface of a zinc-based plated steel sheet that has not been subjected to an appropriate treatment such as chemical conversion treatment or oil coating discolors to a blackish color when placed in a wet environment, and such a black discoloration phenomenon occurs. The reason is that the plating surface is mildly corroded to generate oxygen-deficient non-stoichiometric amorphous zinc oxide. The formation of such an amorphous oxide is due to the fact that the corrosion (oxidation) reaction of zinc does not proceed completely, and therefore, in order to suppress the blackening phenomenon, it is a rate-determining reaction to promote the corrosion reaction. It suffices to accelerate the reduction reaction. In other words, the magnitude of zinc corrosion is determined by the rate of the reduction reaction (a reaction in which oxygen is converted to water on the zinc surface). Since the reduction reaction is usually slow, the oxidation reaction also proceeds at an insufficient rate, and as a result, an oxide with many defects is generated, resulting in a blackish appearance (blackening). On the other hand, if the reduction reaction is sufficiently fast, the formation of oxides by oxidation proceeds sufficiently and blackening does not occur.

From this point of view, in order to suppress blackening of zinc-based plated steel sheets, Ni, Co, Fe and I are generally used.
A method of incorporating an element, such as n, which is more noble than zinc and has an effect of promoting a reduction reaction, into zinc plating or depositing it on the surface of zinc plating is adopted. However,
In this method, since the corrosion reaction of zinc is promoted, the corrosion of zinc is promoted even in a corrosive environment where chloride ions are present.
There is a problem that the corrosion resistance (particularly white rust resistance) deteriorates. Therefore, a method for ensuring blackening resistance without deteriorating corrosion resistance has been sought.

On the other hand, chromate treatment has been widely used as a method for forming a chemical conversion treatment layer for improving the corrosion resistance of a zinc-based plated steel sheet, but recently there has been a demand for a chemical conversion treatment layer which does not use harmful chromium. It is increasing and various corrosion resistant treated layers have been proposed. Among them, the method for forming a treatment layer by electrolytic treatment has advantages such as easier control of the adhesion amount than the method for forming a treatment layer by reaction.For example, the following techniques have been proposed. ing.

(1) A technique of performing cathodic electrolysis in an aqueous solution containing a metal cation selected from Mg, Ca, Ni, Co and Al and an oxidizing agent such as nitrate ion (Japanese Patent Application Laid-Open No. HEI-3-
No. 223472) (2) A technique of performing a cathodic electrolysis treatment in an aqueous solution containing a polycondensed phosphoric acid compound and a colloidal compound, and then applying a clear coating film (JP-A-1-219193). (3) Silica, alumina, titania, A technique of performing cathodic electrolysis in an aqueous solution containing an oxide sol such as zirconia and oxygenate ions such as molybdate ions, tungstate ions, vanadate ions (JP-A-63-1001).
94)

In all of these techniques, electrolysis is performed in an aqueous solution containing an oxide sol, a metal cation, a phosphate, an oxygenate ion or the like to form a treatment layer containing these components on the metal plate surface. This improves the corrosion resistance of the metal plate, but both have the following problems. In the technique of performing electrolysis in an aqueous solution containing a metal cation and an oxidizing agent such as nitrate ion of the above (1), since the component of the obtained treatment layer is only a metal hydroxide, the solubility in water is relatively high, In particular, in the case of an aluminum-based treated layer, the treated layer is easily dissolved in a portion which becomes an alkaline environment during corrosion, and sufficient corrosion resistance cannot be obtained.

In the technique (2) above, a phosphate film can be obtained by electrolytic treatment using a phosphate or a solution containing a metal cation and phosphoric acid. Because it is low and a dense film cannot be obtained,
Corrosion resistance is not sufficient under industrial conditions. In the technique of (3) above, by performing electrolytic treatment using an oxide sol and an aqueous solution containing oxygenate ions, a dense reduced film of oxygenate ions and a film having high film-forming property and high corrosion resistance of the oxide sol. Can be expected to get. In particular, vanadate ions are extremely easy to reduce and can be deposited in a short time, so that a dense film can be obtained and extremely high corrosion resistance can be obtained. However, there is a problem that the reduced film of vanadate ion is apt to turn black.

[0008]

[Patent Document 1] Japanese Patent Laid-Open No. 9-957
No. 96 discloses a technique of performing cathodic electrolysis treatment in a solution containing vanadate and an organic acid having a reducing power. In this treatment, a black film is formed to form a colored film such as bronze color. Only the discoloration was less noticeable, and the black discoloration resistance was not improved by a film with little coloring. On the other hand, Ni, Co, F, which is a method for suppressing the usual blackening,
When the method of including elements such as e and In in the galvanizing or depositing on the galvanizing surface is applied, the blackening resistance is improved, but those elements are also large in the electrolytic deposition reaction of vanadic acid. As a result, there is a problem that the corrosion resistance is significantly reduced. Therefore, hitherto, a vanadate-reduced coating having both a corrosion resistance and a blackening resistance with a coating with little coloration has not been obtained.

Accordingly, an object of the present invention is to provide a surface-treated steel sheet made of a zinc-based plated steel sheet, which has excellent corrosion resistance and blackening resistance, and a method for producing the same.

[0010]

In order to solve the above-mentioned problems, the present inventors have made a detailed study on a film structure and a method of forming the film that highly satisfy the corrosion resistance and the blackening resistance, and as a result, The reaction layer of zinc and S or the adsorption layer of S on the plating film surface layer of the plated steel sheet, that is, the reaction layer or S generated by the reaction between zinc and S of the plating film surface layer was generated by being adsorbed on the zinc of the plating film surface layer. It was found that a surface-treated steel sheet excellent in corrosion resistance and blackening resistance can be obtained by forming an adsorption layer and forming a chemical conversion treatment layer on the adsorption layer.

The reaction layer of zinc and S as described above and S
The adsorption layer of is a zinc-based plated steel sheet immersed in an aqueous solution containing one or more selected from sulfides, sulfide ions, compounds having a thiol group or a thiocarbonyl group, and sulfur, or the anode in the state of being immersed. It was found that stable formation can be achieved by electrolysis. Further, as the chemical conversion treatment layer, particularly excellent blackening resistance and corrosion resistance can be obtained by forming a chemical conversion treatment layer containing a vanadate compound and silica by cathodic electrolysis, preferably containing these as the main components. understood.

The present invention has been made on the basis of the above findings, and its features are as follows. [1] A reaction layer of zinc and S having an S deposition amount of 0.010 to 100 mg / m ² or an adsorption layer of S is provided on the surface layer of the coating film of the zinc-based plated steel sheet, and a chemical conversion treatment layer is provided thereon. A surface-treated steel sheet having excellent corrosion resistance and blackening resistance. [2] In the surface-treated steel sheet according to [1] above, the chemical conversion treatment layer is a film formed by cathodic electrolysis, which is a film containing a vanadate compound and silica, and has excellent corrosion resistance and blackening resistance. Treated steel plate.

[3] In the surface-treated steel sheet according to the above [2], the vanadate compound contained in the chemical conversion treatment layer is a pyrovanadate compound and / or an orthovanadate compound. Excellent surface-treated steel sheet. [4] In the surface-treated steel sheet according to any one of the above [1] to [3],
Inorganic or organic or inorganic-on the upper layer of the chemical conversion treatment layer.
A surface-treated steel sheet excellent in corrosion resistance and blackening resistance, characterized in that an organic top coat layer is formed in a thickness of 0.05 to 3 μm.

[5] A zinc-based plated steel sheet is dipped or dipped in an aqueous solution containing at least one selected from sulfides, sulfide ions, compounds having a thiol group and / or thiocarbonyl group, and sulfur. By performing anode electrolysis in the state, a reaction layer of zinc and S having an S deposition amount of 0.010 to 100 mg / m ² or an adsorption layer of S is formed on the surface layer of the plating film of the zinc-based plated steel sheet. A method for producing a surface-treated steel sheet excellent in corrosion resistance and blackening resistance, which comprises subjecting a galvanized steel sheet to chemical conversion treatment. [6] In the production method of the above-mentioned [5], as the chemical conversion treatment, p containing vanadate or / and a vanadate compound and silica is used.
A method for producing a surface-treated steel sheet excellent in corrosion resistance and blackening resistance, characterized by performing cathodic electrolysis treatment in an electrolytic solution of H6 to 12.

[7] A surface-treated steel sheet excellent in corrosion resistance and blackening resistance, characterized in that the electrolytic solution further contains a polyvalent anion in an amount of 0.01 to 2 mol / L in the production method of [6]. Manufacturing method. [8] In the production method of the above-mentioned [6] or [7], the vanadic acid or / and the vanadate compound contained in the electrolytic solution is selected from pyrovanadate, orthovanadate, pyrovanadate and orthovanadate. A method for producing a surface-treated steel sheet excellent in corrosion resistance and blackening resistance, characterized in that it is one or more of the following. [9] In the manufacturing method according to any one of the above [5] to [8], after chemical conversion treatment, an inorganic or organic or inorganic-organic topcoat coating layer is added to the upper layer of the chemical conversion treatment layer in an amount of 0.05 to 3 μm
The method for producing a surface-treated steel sheet excellent in corrosion resistance and blackening resistance, which is characterized in that

By forming the reaction layer of zinc and S or the adsorption layer of S as described above on the surface layer of the zinc-based plating film,
The reason why the corrosion resistance and the blackening resistance are remarkably improved is not always clear, but since the reaction layer of zinc and S and the adsorption layer of S are in a state where zinc is oxidized, further oxidation is suppressed, and zinc oxidation is suppressed. It is considered that the blackening resistance is increased because the production of the substance is suppressed, while the reaction layer of zinc and S and the adsorption layer of S suppress the oxidation, and as a result, the corrosion reaction is also suppressed and the corrosion resistance is improved.

Further, when the chemical conversion treatment layer contains a vanadate compound and silica (preferably containing them as main components), the following mechanism is considered. That is, since the reaction layer of zinc and S and the adsorption layer of S also have semiconductor-like properties, an electric current flows through the layer, and electrolytic treatment can be performed through this layer. For this reason, by forming a reaction layer of zinc and S or an adsorption layer of S on the surface layer of the plating film, cathode electrolysis treatment is performed in an aqueous solution containing a vanadate compound and silica (preferably containing these as main components). ,
It is considered that it becomes possible to obtain corrosion resistance while ensuring blackening resistance, and it is possible to form a film which is chromium-free but is effective in suppressing metal corrosion and has excellent blackening resistance.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The base steel sheet of the surface-treated steel sheet of the present invention is a zinc-based plated steel sheet, and examples of the zinc-based plated steel sheet include electrogalvanized steel sheet, hot-dip galvanized steel sheet, alloyed hot-dip galvanized steel sheet, Zn-Ni, Zn-C
o, Zn-Co-Mo, alloy electroplated steel sheet having an alloy plated coating such as Zn-Cr, Zn-SiO ₂ dispersed electroplated steel sheets, hot-dip zinc - aluminum alloy coated steel sheets (so-called 5% Al-Zn hot-dip plated steel sheet, 55% Al-Z
n hot-dip galvanized steel sheet), hot-dip zinc-aluminum-magnesium alloy plated steel sheet, hot-dip zinc-magnesium alloy plated steel sheet and the like.

When an electrogalvanized steel sheet is used as a base steel sheet, iron group metal ions (Ni ions, Co ions, Fe ions) are added to the electroplating bath for the purpose of reducing blackening (a kind of oxidation phenomenon on the plating surface). One or more of these metals may be added to the plating film to contain 1 ppm or more of one or more of these metals. In this case, there is no particular upper limit on the iron group metal concentration in the plating film. Also,
In order to prevent film defects and unevenness when an electrolytically treated layer or organic film is formed on the surface of the plating film, alkaline degreasing, solvent degreasing, surface conditioning treatment (alkaline surface A treatment such as a conditioning treatment or an acidic surface conditioning treatment) can be performed in advance.

On the surface of the plating film of the zinc-based plated steel sheet,
A reaction layer formed by the reaction between zinc and S of the plating film or an adsorption layer formed by adsorbing S on zinc of the plating film is formed. The reaction layer of zinc and S or the adsorption layer of S is formed by a dipping treatment or an anode electrolysis treatment described later, and its chemical composition is ZnS _x (SH) _y (however, x
+ Y / 2 = 1), but it does not necessarily have to be a complete sulfide, and ZnO _v (OH) _w mixed with an oxide
S _x (SH) _y (however, v + w / 2 + x + y / 2 = 1)
Even such a composition has a sufficient effect. The amount of adhesion of the reaction layer of zinc and S or the adsorption layer of S is set to be 0.010 to 100 mg / m ² as the amount of S adhesion. The amount of S attached is 0.
Is less than 010mg / m ² is insufficient effect of suppressing the blackening, on the other hand, when it exceeds 100 mg / m ² and the reaction layer or adsorbed layer becomes brittle, corrosion-resistant it becomes easily peeled off from the plated surface is reduced.

In order to form the reaction layer of zinc and S or the adsorption layer of S, a zinc-based plated steel sheet is prepared from sulfide, sulfide ion, compound having thiol group and / or thiocarbonyl group, and sulfur. It is immersed in an aqueous solution containing at least one selected from the above, or the anode electrolysis treatment is performed in the immersed state.

As the sulfide contained in the above aqueous solution,
For example, sodium sulfide (Na ₂ S), potassium sulfide (K ₂ S), ammonium sulfide ((NH ₄ ) ₂ S), calcium sulfide (CaS), strontium sulfide (Sr).
S), aluminum sulfide (Al ₂ S ₃ ), barium sulfide (BaS), germanium sulfide (GeS), manganese sulfide (MnS), lanthanum sulfide (La ₂ S ₃ ), iron sulfide (FeS, Fe ₂ S ₃ ), Molybdenum sulfide (MoS ₃ ,
MoS ₄ ), nickel sulfide (NiS), vanadium sulfide (V ₂ S ₃ , V ₂ S ₄ , V ₂ S ₅ ) and other sulfides, sodium hydrogen sulfide (NaHS), potassium sulfide (KHS),
Hydrosulfides such as ammonium sulfide (NH ₄ HS), sodium polysulfide (Na ₂ S _x ), potassium polysulfide (K ₂
S _x ), polyammonium sulfide ((NH ₄ ) ₂ S _x ), etc. (where x = 2, 3, ...) and the like, and at least one of these is dispersed as a salt in an aqueous solution. Is. As the sulfide ions, sulfides dissociated one or more by dissolution in water of the salt ions (S ^2-), hydrosulfide ions (HS ^-), polysulfide ions (Sx ^2- ).

As the compound having a thiol group and / or a thiocarbonyl group, for example, an aromatic thiol such as an alkanethiol represented by RSH (R is an alkyl group), thiophenol, or a triazinethiol compound,
Examples thereof include compounds having a thiocarbonyl group such as thiuram and thiourea, and one or more of these compounds are dissolved or dispersed in water. Furthermore, examples of sulfur include sulfur flower, precipitated sulfur, purified sulfur, deoxidized sulfur, sulfur powder, colloidal sulfur, and the like, and one or more of these are dissolved or dispersed in water.

Sulfide, sulfide ion, thiol group or /
And a compound having a thiocarbonyl group, and the concentration in one or more aqueous solutions selected from sulfur is preferably 0.0001 mol / L or more, and 0.0001 mol / L or more.
If the concentration is less than the above value, a reaction layer of zinc and S or an adsorption layer of S is not appropriately formed. The pH of the aqueous solution is preferably 8 or higher, and more preferably 10 or higher. This is because when the pH is low, hydrogen sulfide is generated and gives off a bad odor. In order to increase the pH, it is preferable to add hydroxides such as sodium hydroxide and potassium hydroxide, ammonia water, amine compounds and the like.

The zinc-based plated steel sheet is dipped in the above aqueous solution. The immersion time is effective for 1 second or more, but the longer the time, the higher the effect. It is preferably 12 hours or more. The higher the temperature of the aqueous solution is, the more preferable, but 70 ° C. or lower is preferable because the amount of hydrogen sulfide generated increases. On the other hand, if the anode electrolysis is performed in an aqueous solution, the same effect can be obtained in a short time. As the electrolysis method, a constant current method, a constant voltage method, a potential sweep method, or the like can be applied, and the constant current electrolysis is particularly preferable. The current density may be 0.1 to 30 A / dm ² , and the electrolysis time may be 0.1 to 300 seconds.

A chemical conversion treatment layer is formed on the surface of the zinc-based plated steel sheet having the reaction layer of zinc and S or the adsorption layer of S formed on the surface layer of the plating film. The treatment for forming this chemical conversion treatment layer may be either chromate treatment or chromium-free chemical conversion treatment. In this way, the reaction layer of zinc and S or S
By providing the chemical conversion treatment layer on the surface of the zinc-plated steel sheet having the adsorption layer formed thereon, excellent corrosion resistance and blackening resistance can be obtained.

The chromate treatment includes reaction type chromate treatment, coating type chromate treatment, electrolytic chromate treatment and the like, and any treatment may be performed. If necessary, various oxide particles such as silica, organic silane compounds, phosphoric acid, nitric acid, and fluorides containing Cr compounds as the main components, with the aim of improving properties such as corrosion resistance, scratch resistance, and blackening resistance. ,
Treatment with a chromate treatment liquid containing one or more kinds of various reaction accelerators such as silicofluoride and organic resins may be performed. The amount of the chromate-treated layer deposited is preferably in the range of 5 to 300 mg / m ^{2 in} terms of metal Cr, and particularly when the white rust resistance is improved and economical efficiency is also taken into consideration, it is 5 to 60 mg / m ^2. Is preferable, and further 10
The range of ˜30 mg / m ² is more preferable.

Chromium-free chemical conversion treatments include reaction type treatments, coating type treatments, electrolytic type treatments and the like similar to chromate treatments. The composition of the chromium-free chemical conversion treatment layer includes an organic film and an inorganic film. When the chemical conversion treatment layer is an organic film, that is, a film mainly composed of an organic resin,
For example, epoxy resin, polyester resin, polyurethane resin, ethylene copolymer resin containing ethylenically unsaturated carboxylic acid as a polymerization component, polyvinyl resin,
Treatment liquid mainly composed of one or more organic resin components such as polyamide resin and fluorine resin, or corrosion resistance, lubricity, scratch resistance, workability, weldability, electrodeposition paintability, coating adhesion In order to improve properties such as properties, it is possible to use a treatment liquid containing one or more kinds of various oxide particles such as silica, various inorganic pigments such as phosphate, wax particles, organic silane compound, and naphthenate. it can.

When the chemical conversion treatment layer is an inorganic film, that is, a film mainly composed of an inorganic substance, for example, a treatment liquid mainly composed of a silicate such as sodium silicate, potassium silicate or lithium silicate, Alternatively, various oxide particles such as colloidal silica, phosphoric acid, etc. for the purpose of improving properties such as film-forming property, corrosion resistance, lubricity, scratch resistance, workability, weldability, electrodeposition coating property, coating film adhesion, etc. A treatment liquid containing at least one kind of various inorganic pigments such as salts, wax particles, and organic silane compounds can be used.

The above organic film and inorganic film may be formed alone or in combination of two or more layers. In that case, the order of combination of the coatings may be arbitrary, and the inorganic coating may be disposed on the lower layer and the organic coating may be disposed on the upper layer, or vice versa, or three or more layers may be laminated. Further, providing the above organic coating and / or inorganic coating on the chromate-treated coating,
It is more preferable from the viewpoint of white rust resistance. The amount of the above chromium-free chemical conversion treatment layer deposited is 0.05 to 20 μm in terms of film thickness, considering not only corrosion resistance but also economic efficiency.
A range of m is preferred.

Among the chromium-free chemical conversion treatments,
The chemical conversion treatment performed by the electrolytic treatment method is particularly preferable in terms of easiness of production and cost. Further, among the chemical conversion treatment layers obtained by the electrolytic treatment method, particularly by performing cathodic electrolysis treatment in an electrolytic solution (aqueous solution) containing vanadic acid or / and a vanadate compound and silica, preferably containing these as the main components. The formed chemical conversion treatment layer exhibits particularly excellent corrosion resistance and blackening resistance. Therefore, the chemical conversion treatment layer obtained by the electrolytic treatment method preferably contains a vanadate compound and silica, and preferably contains these as the main components. Here, examples of vanadic acid include metavanadic acid, pyrovanadic acid, orthovanadic acid and the like. Examples of the vanadate compound include ammonium vanadate, sodium vanadate, potassium vanadate, strontium vanadate, sodium hydrogen vanadate, metavanadate salts such as phosphovanadate, pyrovanadate, orthovanadate, and polyvanadate. Salts and the like can be mentioned, and one or more of these can be used.

As described above, there are various kinds of vanadic acid, such as metavanadic acid, pyrovanadic acid, orthovanadic acid, and so far, metavanadic acid has been used as a raw material for industry. As a result of detailed examination of the action and effect on the corrosion resistance, it was found that the use of pyrovanadic acid or orthovanadic acid gave better corrosion resistance than the use of metavanadic acid. The reduction products of vanadate ion by cathodic electrolysis are VO and V ₂ O.
_3, VO ₂ or the like but over a wide, by using a pyrovanadates or orthovanadate, that the proportion of highly dense oxide increases, is assumed to be obtained particularly good corrosion resistance at the same deposition amount It Therefore, as the vanadate compound contained in the chemical conversion treatment layer, a pyrovanadate compound and / or an orthovanadic acid compound are particularly preferable, and vanadic acid added to the electrolytic treatment liquid for forming such a chemical conversion treatment layer. Alternatively, as the vanadic acid compound, it is preferable to use one or more selected from pyrovanadate, orthovanadate, pyrovanadate, and orthovanadate.

As silica to be added to the electrolytic treatment liquid, an aqueous dispersion liquid such as silica sol, or silica fine particles such as fumed silica and white carbon dispersed in water can be used. The primary particle size and shape of silica are not particularly specified, but in order to form a dense treatment layer,
Those having a small primary particle size are preferable.

Inclusion of vanadic acid compound in chemical conversion treatment layer
The amount is 1-100 mg / m in terms of vanadium.^TwoIs appropriate
And its content is 1 mg / m^TwoIf less than, the effect of improving corrosion resistance
Not enough fruits, while 100mg / m^TwoOver the skin
The coloring of the film is conspicuous and the film appearance tends to be inferior. Also,
Content of silica in the treatment layer is 1 to 100 mg / m ^Two
Is appropriate, and the content is 1 mg / m^TwoCorrosion resistance below
The effect of improving the sex is not sufficient, while 100mg / m^TwoTo
If it exceeds the range, the coloration of the film is conspicuous and the film appearance tends to be inferior.
It

The concentration of vanadic acid or / and a vanadate compound in the electrolytic treatment liquid (aqueous solution) for forming the chemical conversion treatment layer is 0.001 to 3 mol / L,
The appropriate concentration of silica is 0.01 to 2 mol / L. If the concentration of vanadic acid or / and vanadate compound in the electrolytic treatment liquid is less than 0.001 mol / L, the denseness of the treatment layer formed is not sufficient, while if it exceeds 3 mol / L, precipitates are formed. It is not preferable because it is easily generated. Further, the concentration of silica in the electrolytic treatment liquid is 0.01 mol / L.
If it is less than 2, the effect of improving the corrosion resistance due to silica cannot be sufficiently obtained, while if it exceeds 2 mol / L, the stability of the liquid is lowered and the compactness of the chemical conversion treatment layer is adversely affected.

Furthermore, when polyvalent anions such as sulfate ions and phosphate ions are added to the above-mentioned electrolytic solution, the amount of silica deposited increases and the corrosion resistance improves. The reason for this is not clear, but it is because the presence of polyvalent ions in the aqueous solution causes the polyvalent ions to be adsorbed on the silica surface, thereby increasing the surface charge of silica and increasing the amount of migration and deposition during electrolysis. Conceivable. To add such polyvalent ions to the electrolytic solution, sodium sulfate, ammonium sulfate, water-soluble sulfates such as potassium sulfate, sodium phosphate, ammonium phosphate, water-soluble phosphates such as potassium phosphate,
One or more kinds of silicates and borates may be added to the electrolytic solution. Further, the optimum concentration of polyvalent anion in the electrolytic solution is 0.01 to 2 mol / L, and if the concentration of polyvalent anion is less than 0.01 mol / L, the effect of addition is not sufficient, On the other hand, if it exceeds 2 mol / L, there is a possibility that a problem may occur in the uniformity of the treated layer. Furthermore, in the above electrolytic solution, components such as sodium perchlorate and ammonium perchlorate that enhance electrical conductivity, pH buffers such as sodium acetate and sodium citrate, and further densification of the chemical conversion treatment layer are aimed at. Additional components such as water-soluble organic resin may be added as appropriate.

Further, an oxidizing agent component such as nitrate ion, nitrite ion, chlorate ion, perchlorate ion, permanganate ion, bromate ion and molybdate ion may be added to the above-mentioned electrolytic solution. This makes it possible to generate a more precise chemical conversion treatment layer. Since all of these components are reduced while consuming hydrogen ions at the potential at which the chemical conversion treatment layer is formed, it is considered that hydrogen generation is suppressed and a dense chemical conversion treatment layer is formed. Among the above oxidizer components, nitrate ions are particularly effective because their reactivity is relatively easy to control. Further, in order to add the above-mentioned oxidizer component to the electrolytic solution, it is appropriate to add a water-soluble metal salt such as an alkali metal salt.
The optimum concentration of the above-mentioned oxidizing agent (ion) in the electrolytic solution is 0.001 to 2 mol / L. If the concentration of the oxidizing agent is less than 0.001 mol / L, the effect of addition is not sufficient. On the other hand, if it exceeds 2 mol / L, the reactivity becomes extremely high, which may cause a problem in the uniformity of the chemical conversion treatment layer.

A pH of 6 to 12 is suitable for the electrolytic solution. Reaction layer of zinc and S formed on the surface of plating film or S
Since the adsorption layer of is soluble in acid and strong alkaline, the pH of the electrolytic solution is stable p
It is preferable to set it to 6 to 12 which is the H region. The electrolysis conditions for the chemical conversion treatment are not particularly limited, but the conditions of electrolysis at a constant current using a zinc-based plated steel sheet as the cathode are particularly desirable in that the chemical conversion treatment layer can be effectively formed without metal elution. The current density is preferably about 0.1 to 50 A / dm ² . Further, it is preferable that the current density is low in order to suppress the generation of hydrogen gas.
~20A / dm ² is preferred.

The electrolysis time is not particularly limited, and may be a pattern in which there are a plurality of electrolysis cells and the energization is in multiple stages. In this case, the total energization time is preferably 30 seconds or less. When energized for a time longer than this, not only a problem in production efficiency occurs, but also a problem that the chemical conversion treatment layer becomes thick and the treatment layer is liable to be lost easily occurs. A suitable energization time is 0.1 to 5 seconds. The temperature of the electrolytic bath is not particularly limited, but is preferably about 40 to 80 ° C.

The electrolysis method is not particularly limited, but a usual electrolysis cell in which a plated steel sheet passes through cells in which anodes are arranged in parallel can be used. In this case, both vertical cells and horizontal cells can be applied. The counter electrode of the plated steel sheet that serves as the cathode is not particularly limited, but any of an insoluble anode such as a Pb alloy-based electrode and an iridium oxide-coated electrode, and a self-fluxing anode that can replenish the components of the electrolytic bath are applicable. The method of washing with water after electrolysis is not particularly limited, but usually,
Spray water washing is performed. The washing temperature is not particularly limited, but is usually room temperature to 80 ° C. The drying method is also not particularly limited, and high frequency induction heating, hot air, infrared ray, or the like can be used for drying.

Above the chemical conversion treatment layer as described above,
An inorganic or organic or inorganic-organic topcoat coating layer can be formed, which further improves corrosion resistance. The top coat layer may be a single layer, but for example, a multi-layer coating in which an inorganic coating layer is formed on the chemical conversion treatment layer by dipping or spraying, and an organic coating layer is further formed on the inorganic coating layer. You may form a layer.

As the inorganic top coat layer, for example,
Water glass, a silicic acid-based aqueous solution such as lithium silicate, a solution in which a silicic acid ester such as methyl silicate or ethyl silicate is dissolved in an organic solvent such as ethanol or methyl cellosolv, or a mixed solution of an organic solvent and water, a silane coupling agent. Solution in water or an organic solvent, a solution in which a silicone resin is dissolved in a solvent, a phosphate aqueous solution, or silica, alumina, magnesia, titania in these solutions,
Using those in which oxide particles such as zirconia are dispersed,
A coating layer obtained by applying the material by a coating method, a dipping method, a spray method, or the like and then drying it may be mentioned.

A typical example of the organic top coat layer is an organic resin film. The base resin of the organic resin film is not particularly limited, and may be any of water-soluble resin, water-dispersible resin and organic solvent-soluble resin, and the resin type may be epoxy resin, urethane resin, acrylic resin, acrylic-ethylene Polymers, acrylic-styrene copolymers, alkyd resins, polyester resins, ethylene resins and the like can be used, but from the viewpoint of corrosion resistance, it is preferable to use an organic polymer resin having an OH group and / or a COOH group. . Of these, thermosetting resins are preferred,
Further, an epoxy resin or a modified epoxy resin is most preferable. Thermosetting epoxy resin, thermosetting modified epoxy resin, acrylic copolymer resin copolymerized with epoxy group-containing monomer, polybutadiene resin having epoxy group,
Examples thereof include a polyurethane resin having an epoxy group, and an addition product or a condensation product of these resins. One kind of these epoxy group-containing resins can be used alone, or two or more kinds can be mixed and used.

Examples of the organic polymer resin having an OH group and / or a COOH group include epoxy resin, polyhydroxypolyether resin, acrylic copolymer resin, ethylene-acrylic acid copolymer resin, alkyd resin and polybutadiene. Examples thereof include resins, phenol resins, polyurethane resins, polyamine resins, polyphenylene resins, and mixtures or addition polymers of two or more of these resins.

As the epoxy resin, bisphenol A, bisphenol F, novolac, etc. are glycidyl etherified epoxy resin, bisphenol A is added with propylene oxide, ethylene oxide or polyalkylene glycol, and glycidyl etherified epoxy resin is further added. A group epoxy resin, an alicyclic epoxy resin, a polyether epoxy resin, or the like can be used. These epoxy resins preferably have a number average molecular weight of 1500 or more, especially when curing at low temperature is required. The above epoxy resins may be used alone or as a mixture of different types.

Examples of the modified epoxy resin include resins obtained by reacting various modifying agents with the epoxy group or hydroxyl group in the above epoxy resin. For example, an epoxy ester resin obtained by reacting a carboxyl group in a drying oil fatty acid,
Epoxy acrylate resin modified with acrylic acid, methacrylic acid, etc., urethane modified epoxy resin made to react with isocyanate compound, amine added urethane modified epoxy resin made by adding alkanolamine to urethane modified epoxy resin made to react epoxy compound with isocyanate compound, etc. Can be mentioned.

The above polyhydroxypolyether resin is
Mononuclear or dinuclear type dihydric phenol or mononuclear type and 2
It is a polymer obtained by polycondensing a mixed dihydric phenol with a karyotype in the presence of an alkali catalyst with an approximately equimolar amount of epihalohydrin. Representative examples of mononuclear dihydric phenols include resorcin, hydroquinone, and catechol, and representative examples of dinuclear phenols include bisphenol A. These may be used alone or in combination of two or more. May be.

Examples of the urethane resin include oil-modified polyurethane resin, alkyd polyurethane resin, polyester polyurethane resin, polyether urethane resin, polycarbonate polyurethane resin and the like. Examples of the alkyd resin include oil-modified alkyd resin, rosin-modified alkyd resin, phenol-modified alkyd resin, styrenated alkyd resin, silicon-modified alkyd resin, acrylic-modified alkyd resin, oil-free alkyd resin, and high-molecular-weight oil-free alkyd resin. Can be mentioned.

As the acrylic resin, for example, polyacrylic acid and its copolymer, polyacrylic acid ester and its copolymer, polymethacrylic acid ester and its copolymer, polymethacrylic acid ester and its copolymer,
Urethane-acrylic acid copolymer (or urethane-modified acrylic resin), styrene-acrylic acid copolymer, etc. are mentioned, and resins obtained by modifying these resins with other alkyd resins, epoxy resins, phenol resins, etc. are used. May be.

Examples of the ethylene resin include ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, ethylene-based copolymers such as carboxyl-modified polyolefin resin, ethylene-unsaturated carboxylic acid copolymers, and ethylene-based copolymers. Examples thereof include ionomers, and resins obtained by modifying these resins with other alkyd resins, epoxy resins, phenol resins and the like may be used. Examples of the acrylic silicone resin include those containing a hydrolyzable alkoxysilyl group in the side chain or terminal of an acrylic copolymer as a main component, and a curing agent added thereto. When these acrylic silicone resins are used, excellent weather resistance can be expected.

As the fluororesin, there is a fluoroolefin copolymer, and examples thereof include alkyl vinyl ether, synchroalkyl vinyl ether, carboxylic acid modified vinyl ester, hydroxyalkyl allyl ether, tetrafluoropropyl vinyl ether and the like as monomers. There is a copolymer obtained by copolymerizing a monomer (fluoroolefin). When these fluororesins are used, excellent weather resistance and excellent hydrophobicity can be expected.

Further, for the purpose of lowering the drying temperature of the resin, it is preferable to use a core / shell type water-dispersible resin composed of resins having different glass transition temperatures between the core portion and the shell portion of the resin particles. You can Further, using a water-dispersible resin having a self-crosslinking property, for example, by providing an alkoxysilane group to the resin particles, the silanol group is generated by the hydrolysis of the alkoxysilane during the heating and drying of the resin, and the silanol group between the resin particles is generated. Inter-particle cross-linking utilizing the dehydration condensation reaction of can be used. Further, as the resin used for the organic film, an organic composite silicate obtained by combining the organic resin with silica via a silane coupling agent is also suitable.

Further, it is particularly desirable to use a thermosetting resin for the purpose of improving the corrosion resistance and workability of the organic resin film. In this case, urea resin (such as butylated urea resin),
An amino resin such as a melamine resin (butylated melamine resin), a butylated urea / melamine resin, a benzoguanamine resin, and a curing agent such as a blocked isocyanate, an oxazoline compound, and a phenol resin can be added.

In the above-mentioned film, oxide fine particles (for example, silicon oxide, aluminum oxide, zirconium oxide, titanium oxide, cerium oxide, antimony oxide, etc.) are added as a rust preventive additive for further improving corrosion resistance.
Polyphosphate, phosphate (eg, zinc phosphate, aluminum dihydrogen phosphate, zinc phosphite, etc.), vanadate, molybdate, phosphomolybdate (eg, aluminum phosphomolybdate, etc.), organic Phosphoric acid and its salts (for example, phytic acid, phytate, phosphonic acid,
Phosphonates and their metal salts, alkali metal salts),
One or more compounds selected from organic inhibitors (eg, hydrazine derivatives, thiol compounds, dithiocarbamates, etc.), organic compounds (polyethylene glycol), etc. may be added to the coating composition.

Further, as other additives, organic coloring pigments (eg, condensed polycyclic organic pigments, phthalocyanine organic pigments, etc.), coloring dyes (eg, organic solvent-soluble azo dyes, water-soluble azo metal dyes, etc.) ), Inorganic pigments (such as titanium oxide), chelating agents (such as thiol), conductive pigments (such as metal powders of zinc, aluminum, nickel, etc., iron phosphide, antimony-doped tin oxide, etc.), cups A ring agent (for example, a silane coupling agent, a titanium coupling agent, etc.), a melamine-cyanuric acid adduct, etc. can be added.

If necessary, a solid lubricant may be added to the organic resin film for the purpose of improving the processability of the film. Examples of the solid lubricant applicable to the present invention include the following, and one or more of these may be used. (1) Polyolefin wax, paraffin wax: for example, polyethylene wax, synthetic paraffin, natural paraffin, microwax, chlorinated hydrocarbon, etc. (2) Fluororesin fine particles: For example, polyfluoroethylene resin (polytetrafluoroethylene resin, etc.) , Polyvinyl fluoride resin, polyvinylidene fluoride resin, etc.

In addition to these, fatty acid amide compounds (eg stearic acid amide, palmitic acid amide,
Methylene bis stearamide, ethylene bis stearamide, oleic acid amide, esyl acid amide, alkylene bis fatty acid amide, etc.), metallic soaps (eg calcium stearate, lead stearate, calcium laurate, calcium palmitate, etc.), metal One or more of sulfides (eg, molybdenum disulfide, tungsten disulfide, etc.), graphite, fluorinated graphite, boron nitride, polyalkylene glycol, and alkali metal sulfates may be used.

Among the above solid lubricants, particularly polyethylene wax, fluororesin fine particles (among others, poly 4
Fluorinated ethylene resin fine particles) are suitable. As the polyethylene wax, for example, Ceridust 9615A, Ceridust 3715, Ceridust 3 manufactured by Hoechst Co.
620, Ceridust 3910, Sun Wax 131-P, San Wax 161-P manufactured by Sanyo Kasei Co., Ltd., Chemipearl W-100, Chemipearl W-200, Chemipearl W-500, Chemipearl W-500 manufactured by Mitsui Petrochemical Co., Ltd.
W-800, Chemipearl W-950 and the like can be used.

Further, as the fluororesin fine particles, tetrafluoroethylene fine particles are most preferable, and for example, Lubron L-2 and Lubron L- manufactured by Daikin Industries, Ltd.
5, MP1100, MP12 manufactured by Mitsui DuPont Co., Ltd.
00, full-on dispersion AD1, full-on dispersion AD2, full-on L141J, full-on L15 manufactured by Asahi IC Fluoropolymers Co., Ltd.
0J and FLUON L155J are suitable.

Among these, a particularly excellent lubricating effect can be expected by using a combination of polyolefin wax and tetrafluoroethylene fine particles. The compounding amount of the solid lubricant in the organic resin film is 100 parts by weight of the base resin (solid content)
To 1 to 80 parts by weight (solid content), preferably 3 to 4
0 parts by weight (solid content) is suitable. If the blending amount of the solid lubricant is less than 1 part by weight, the lubricating effect is poor, while if the blending amount exceeds 80 parts by weight, the coating property is deteriorated, which is not preferable. A coating composition for forming a film, which contains the above-mentioned base resin and additional components, usually contains a solvent (organic solvent and / or water), and further contains a neutralizing agent and the like as necessary.

As the inorganic-organic top coat layer, in addition to the above-mentioned coating composition containing an organic resin and an inorganic compound and dried to form a coating layer, an organic resin and an inorganic compound are used. A coating composition obtained by chemically reacting a system compound in a solution may be applied and dried to form a coating layer.

The dry film thickness of the above-mentioned inorganic or organic or inorganic-organic top coat layer is 0.05 to 3 μm.
m, preferably 0.1 to 1 μm. When the film thickness of the overcoat coating layer is less than 0.05 μm, the effect of the coating layer is not sufficiently exhibited. On the other hand, when the film thickness exceeds 3 μm, corrosion resistance is good, but blackening resistance is poor, and conductivity is also poor, and problems such as welding are not possible.

A sealing layer may be formed on the chemical conversion treatment layer, and the above-mentioned overcoat coating layer may be formed on the sealing layer. This sealing layer is formed mainly for the purpose of sealing defects in the chemical conversion treatment layer, and can be formed using, for example, the above-mentioned coating composition for the overcoat coating layer. The thickness of the sealing layer is not particularly limited, but is generally 0.05 to 1 μm, preferably 0.05 to
About 0.5 μm is preferable. Further, in order to form the sealing layer, for example, after the electrolytic treatment for forming the chemical conversion treatment layer is performed, the coating composition is applied by a spray method, a dipping method, a coating method, or the like without or without water washing. Then
dry.

To form an overcoat coating layer on the chemical conversion treatment layer or the sealing layer, a coating composition for overcoating is applied to the chemical conversion treatment layer or the sealing layer.
Heat dry. The method of applying the coating composition for topcoating is not particularly limited, and any of a coating method, a dipping method, an electrolytic method, a spray method and the like may be used. Further, in the coating method, any coating means such as a roll coater (3 roll method, 2 roll method, etc.), a squeeze coater, a die coater, etc. may be used. In addition, after the coating treatment with a squeeze coater, the dipping treatment, the spray treatment, the coating amount is adjusted by the air knife method or the roll squeezing method, and the appearance is made uniform
It is also possible to make the film thickness uniform.

The formation of the overcoat layer is usually carried out following the above-mentioned electrolytic treatment-water washing-drying step for forming the chemical conversion treatment layer, but if necessary, treatment is successively carried out after water washing. May be. The temperature of the treatment liquid for forming the overcoat layer is not particularly limited, but normally room temperature to 60 ° C is suitable. It is uneconomical at room temperature or below because equipment for cooling etc. is required.
If the temperature exceeds ℃, water will be evaporated and liquid management will be complicated.

After applying the coating composition for topcoating,
Usually, it is heated and dried without washing with water, but may be washed with water after coating. The method for heating and drying the coating composition is not particularly limited and may be any of high frequency induction heating, drying with hot air, infrared rays and the like. The heating and drying temperature is 50 to 300 at the ultimate plate temperature.
℃, preferably 80-200 ℃, more preferably 80
It is suitable to carry out in the range of up to 160 ° C.

[0067]

[Examples] [Example 1] Various zinc-plated steel sheets shown in Table 1 were alkali-degreased, washed with water and dried, and then S component (compound having thiol group or thiocarbonyl group, sulfide, sulfide ion) , One or more selected from sulfur)
Immersion treatment or anodic electrolysis treatment was carried out in an aqueous solution containing (solution temperature: 60 ° C.). Next, chemical conversion treatment was performed using the chemical conversion treatment liquids shown in Tables 2 and 3 to obtain surface-treated steel sheets. The surface-treated steel sheet obtained as described above was subjected to the following tests to evaluate the corrosion resistance and the blackening resistance. The results are shown in Tables 4 and 5 together with the treatment conditions with the aqueous solution containing the above S component, the amount of S attached by this treatment, and the chemical conversion treatment conditions.

(1) Corrosion resistance A salt spray test (JIS Z 2371) was carried out on the test material, and the corrosion occurrence area ratio after 48 hours was evaluated as follows. Pass 2 or more points. 5 points No corrosion occurrence 4.5 points Corrosion occurrence area ratio less than 3% 4 points Corrosion occurrence area ratio 3% or more but less than 5% 3.5 points Corrosion occurrence area ratio 5% or more but less than 10% 3 points Corrosion occurrence area ratio 10% or more, less than 15% 2.5 points Corrosion occurrence area ratio 15% or more, less than 30% 2 points Corrosion occurrence area ratio 30% or more, less than 50% 1.5 points Corrosion occurrence area ratio 50% or more, less than 70% 1 point Corrosion occurrence area ratio 70% or more

(2) A test for leaving the blackening resistance test material left in a high temperature and high humidity environment of 80 ° C. and 98% RH for 24 hours was performed. The color tone before and after this test was measured by the Lab method, and the measured value (L Value before and after the test ΔL
Was evaluated as follows. ◎ to △ are passed. ⊚: ΔL is less than 1 ○: ΔL is 1 or more and less than 2 Δ: ΔL is 2 or more and less than 3 ×: ΔL is 3 or more

The S adhesion amount shown in Tables 4 and 5 is as follows.
I asked for it. That is, the treatment layer (reaction of S or
Adsorption layer and chemical conversion treatment layer above it) and zinc-based plating film
Combined and dissolved in acid, the amount of S in this solution was measured by ICP method.
Measurement, and the measured value is S ₍₁₎And Meanwhile, in advance
Zinc-based plating film that does not have the above treatment layer as a blank
Is also dissolved in an acid, and the amount of S in this solution is measured by the ICP method.
Measurement, and the measured value is S₍₀₎And And S
₍₁₎-S₍₀₎The amount of S in the treated layer was determined by.

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

[Table 3]

[0074]

[Table 4]

[0075]

[Table 5]

Example 2 Various zinc-based plated steel sheets shown in Table 1 were subjected to alkaline degreasing treatment, washed with water and dried, and then S component (compound having thiol group or thiocarbonyl group,
The immersion treatment or the anode electrolysis treatment was performed in an aqueous solution (solution temperature: 60 ° C.) containing sulfide, sulfide ion, and sulfur). Then
Chemical conversion treatment was performed using an electrolytic bath having the composition shown in Tables 6 and 7 (bath in which the components of the same table were dissolved in ion-exchanged water, bath temperature 50 ° C.), followed by hot air drying to obtain a surface-treated steel sheet. It was The pH values of the baths shown in Tables 6 and 7 are values at 50 ° C., and when the pH value was raised, it was adjusted using diluted sodium hydroxide.

For some of the surface-treated steel sheets, the organic coating composition shown in Table 8 or the inorganic coating composition shown in Table 9 was applied using a roll coater, dried by heating, and subjected to chemical conversion treatment. A surface-treated steel sheet having a top coat layer on top of the layer was prepared. The film thickness of the overcoat coating layer was adjusted by adjusting the solid content of the coating composition, the rolling force of the coating roll, the rotation speed, and the like. The surface-treated steel sheet thus obtained was subjected to the same tests as in Example 1 to evaluate the corrosion resistance and the blackening resistance. The results are shown as follows: treatment conditions with an aqueous solution containing the above S component, S adhesion amount by this treatment, chemical conversion treatment conditions and V (or Mn) by this treatment,
Table 10 together with the Si adhesion amount and the processing conditions of the top coat layer
It shows in Table 21.

The amounts of S, V (or Mn) and Si in the treated layers shown in Tables 10 to 21 were determined as follows. That is, the treatment layer (S reaction or adsorption layer and the chemical conversion treatment layer above it) and the zinc-based plating film are combined and dissolved in an acid, and the S amount, V amount (or Mn amount), Si
The amounts were measured by the ICP method, and the measured values were taken as S ₍₁₎ , V ₍₁₎ (or Mn ₍₁₎ ) and Si ₍₁₎ , respectively. On the other hand, as a blank, a zinc-based plating film without the above-mentioned treatment layer was previously dissolved in an acid, and the S content, V content (or Mn content), and Si content in this solution were measured by the ICP method, and their measurements Values are S ₍₀₎ and V respectively
₍₀₎ (or M ₍₀₎ ) and Si ₍₀₎ . And
S ₍₁₎ -S ₍₀₎ , V ₍₁₎ -V ₍₀₎ , Mn ₍₁₎
The amount of S, the amount of V (or the amount of Mn), and the amount of Si in the treated layer were obtained from —Mn ₍₀₎ and Si ₍₁₎ —Si ₍₀₎ , respectively.

[0079]

[Table 6]

[0080]

[Table 7]

[0081]

[Table 8]

[0082]

[Table 9]

[0083]

[Table 10]

[0084]

[Table 11]

[0085]

[Table 12]

[0086]

[Table 13]

[0087]

[Table 14]

[0088]

[Table 15]

[0089]

[Table 16]

[0090]

[Table 17]

[0091]

[Table 18]

[0092]

[Table 19]

[0093]

[Table 20]

[0094]

[Table 21]

[0095]

As described above, the present invention provides a surface-treated steel sheet having both excellent corrosion resistance and blackening resistance.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C25D 11/00 301 C25D 11/00 301 (72) Inventor Naoto Yoshimi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo No. Japan Steel Pipe Co., Ltd. (72) Inventor Takahiro Kubota 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Satoshi Ando 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Japan Inside the Steel Pipe Co., Ltd. (72) Inventor Yoshiharu Sugimoto 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Japan Inside Steel Pipe Co., Ltd. (72) Masaaki Yamashita 1-2-1 Marunouchi, Chiyoda-ku, Tokyo In-house F-term (reference) 4D075 AC92 BB73X CA32 CA33 CA50 DB05 DC03 DC12 DC18 4F100 AA02C AA09B AA20C AA22 AB03A AB10 AB16 AB18 AB18A AB31 AR00C BA03 BA 04 BA07 BA10A BA10C BA10D CC00D EH46 EH71A EJ65D EJ68C EJ69 GB07 GB32 GB48 JA20D JB02 JD14B JN28 YY00B YY00D 4K044 AA02 AB02 BA02 BA10 BA14 BA19 BA21 BB04 BC02 BC03 BC09 CA11 CA17 CA18 CA64

Claims (9)

[Claims] 1. A surface layer of a zinc-plated steel sheet,
Excellent in corrosion resistance and blackening resistance characterized by having a reaction layer of zinc and S having an S deposition amount of 0.010 to 100 mg / m ² or an adsorption layer of S, and having a chemical conversion treatment layer as an upper layer thereof. Surface treated steel sheet. 2. The surface-treated steel sheet excellent in corrosion resistance and blackening resistance according to claim 1, wherein the chemical conversion treatment layer is a film containing a vanadate compound and silica formed by cathodic electrolysis treatment. . 3. The surface-treated steel sheet excellent in corrosion resistance and blackening resistance according to claim 2, wherein the vanadate compound contained in the chemical conversion treatment layer is a pyrovanadate compound and / or an orthovanadate compound. . 4. An inorganic-based or organic-based or inorganic-organic-based topcoat coating layer is formed on the chemical conversion treatment layer in an amount of 0.05 to 3 μm.
The surface-treated steel sheet excellent in corrosion resistance and blackening resistance according to claim 1, 2 or 3, wherein the surface-treated steel sheet is formed with a film thickness of m. 5. A zinc-based plated steel sheet is immersed or immersed in an aqueous solution containing at least one selected from sulfides, sulfide ions, compounds having a thiol group and / or thiocarbonyl group, and sulfur. To form a reaction layer of zinc and S having an S deposition amount of 0.010 to 100 mg / m ² or an adsorption layer of S on the surface layer of the plating film of the zinc-based plated steel sheet, and then the zinc is applied. A method for producing a surface-treated steel sheet excellent in corrosion resistance and blackening resistance, which comprises subjecting a galvanized steel sheet to chemical conversion treatment. 6. The corrosion resistance and blackening resistance according to claim 5, wherein the cathodic electrolysis treatment is performed as a chemical conversion treatment in an electrolytic solution containing vanadic acid or / and a vanadic acid compound and silica at a pH of 6 to 12. Of excellent surface-treated steel sheet. 7. The electrolytic solution further comprises a polyvalent anion of 0.0
The method for producing a surface-treated steel sheet excellent in corrosion resistance and blackening resistance according to claim 6, characterized in that the content is 1 to 2 mol / L. 8. The vanadic acid and / or vanadate compound contained in the electrolytic solution is one or more selected from pyrovanadate, orthovanadate, pyrovanadate and orthovanadate. A method for producing a surface-treated steel sheet having excellent corrosion resistance and blackening resistance according to claim 6 or 7. 9. After the chemical conversion treatment, an inorganic or organic or inorganic-organic topcoat coating layer having a thickness of 0.05 to 3 μm is formed on the chemical conversion treatment layer. The method for producing a surface-treated steel sheet excellent in corrosion resistance and blackening resistance according to 5, 6, 7 or 8.