KR101077890B1 - Additives for Zn-Ni alloy electrodeposition electrolyte, Zn-Ni alloy electrodeposition electrolyte comprising the same and method for manufacturing Zn-Ni alloy electrodeposited steel sheet using the same - Google Patents

Abstract

The present invention relates to an additive composition for a zinc-nickel electroplating solution comprising water, carboxylic acid and boric acid, a zinc-nickel electroplating solution composition comprising the same, and a method for manufacturing a zinc-nickel electroplating steel sheet using the same. , The additive composition for the zinc-nickel electroplating solution according to the present invention can form a uniform electrodeposition layer, and can provide excellent plating adhesion, minimization of burning, and excellent surface appearance and surface roughness.

Carboxylic acid, boric acid, electroplating, additives

Description

Additives composition for zinc-nickel electroplating solution, zinc-nickel electroplating liquid composition comprising the same and method for manufacturing zinc-nickel electroplating steel sheet using same {Additives for Zn-Ni alloy electrodeposition electrolyte, Zn-Ni alloy electrodeposition electrolyte comprising the same and method for manufacturing Zn-Ni alloy electrodeposited steel sheet using the same}

The present invention enables the formation of a uniform electrodeposition layer, which has good surface roughness, excellent plating adhesion and reducing the occurrence of burning of the plating layer, and provides an additive composition for zinc-nickel electroplating solution that provides a good surface appearance. It relates to a zinc-nickel electroplating liquid composition comprising the same and a method of manufacturing a zinc-nickel electroplating steel sheet using the same.

Steel sheets, in particular, electroplated steel sheets produced by zinc electroplating, are simple to manufacture and excellent in corrosion resistance, and their usage is gradually increasing in the fields of home appliances, automobiles, construction, and the like.

On the other hand, with recent technological developments, as the demand of consumers for better products increases, the demand for simpler and easier corrosion-resistant steel sheets, especially galvanized steel sheets, is increasing. However, conventional galvanized steel sheet had to increase the thickness of the galvanized layer in order to secure corrosion resistance under severe atmosphere. The increase in the thickness of the plated layer has a problem in that the cost increases, the adhesion of the plated layer is lowered, and the workability is lowered, and in recent years, there is a demand for technology development to improve it.

As such an example, many attempts have been made to improve moldability, that is, workability. Among them, a method using zinc-nickel electroplating has been mainly used. In the zinc-nickel alloy electroplating method, a chloride-based solution, a sulfide-based solution, or a cyanide-based solution is used. Among them, since the chloride-based solution mainly uses a soluble (soluble) anode, a sulfide bath using an insoluble anode is used. Compared to the above, it is known that the solution is easy to control, inexpensive, and has excellent electrical conductivity, and is suitable for high current density plating.

However, in the plating method using a chloride-based solution, when the current density increases, the surface appearance of the plating layer decreases, the surface becomes rough, and the post-treatment process is difficult. In particular, the Zn-Ni alloy electroplating of the chloride bath uses a soluble anode and a cathode, and due to the large natural potential difference between zinc and nickel, a zinc hydroxide-based film was formed on the zinc anode during plating. As a result, the adhesion of the plating layer is deteriorated, edge burning and non-uniform plating are performed at high current density, and the surface appearance of the plating layer is poor.

As a way to solve this problem,

Japanese Patent Application Laid-Open No. 60-12434 describes the addition of surfactants such as polyoxyl alkylene salt and benzyl acetone, which are good gloss and maintain uniform electrodeposition, but there is a problem that it is difficult to secure good adhesion of the plating layer.

Further, according to Japanese Patent JP 93-167094, the addition of an organic compound contained 0.001-10 wt% of carbon in the plating layer to improve workability, but there was a drawback in that the adhesion decreased.

Japanese Patent Publication No. 2761470 discloses polyethylene glycol having a molecular weight of 400-800 and nicotinic acid, urea, thiourea, nicotinamide, thioglycolic acid, which are nonionic surfactants. The addition of one or more compounds selected from the back improves needle defects and reduces the burning area, but does not improve the problem of poor surface gloss and adhesion.

The present invention is to solve the above problems, the technical problem of the present invention is to improve the roughness due to the good reactivity of the anode and the electrodeposition (電 着) reaction, resulting in a good surface appearance, excellent plating adhesion and burning (burning) It is to provide an additive composition for zinc-nickel electroplating solution that can form a plating layer with low generation).

In addition, another technical problem to be solved by the present invention is a zinc-nickel electroplating liquid composition comprising zinc ions, nickel ions, chlorine ions and the zinc-nickel electroplating solution additive composition of the present invention and zinc-nickel electroplating steel sheet using the same It is to provide a manufacturing method.

The present invention is to solve the above problems,

Contains water and additives,

The additive provides an additive composition for a zinc-nickel electroplating solution comprising a carboxylic acid and an inorganic acid having at least one carboxyl group in its structure.

The invention also provides gold zinc ions; Nickel ions; Chlorine ion; And it provides a zinc-nickel electroplating liquid composition comprising the additive composition for a zinc-nickel electroplating solution of the present invention and a method for producing a zinc-nickel electroplating steel sheet using the same.

The additive composition for the zinc-nickel electroplating solution according to the present invention is capable of forming a uniform electrodeposition layer, exhibits excellent plating adhesion, and minimizes occurrence of burning. In addition, the electroplated steel sheet formed from the additive composition for zinc-nickel electroplating solution has excellent surface appearance and surface roughness.

The present invention

Contains water and additives,

The additive is an additive composition for zinc-nickel electroplating solution comprising 1 part by weight of carboxylic acid having at least one carboxyl group and 5-10 parts by weight of at least one inorganic acid selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, boric acid, and chromic acid. It is about.

In addition,

Zinc ions;

Nickel ions;

Chlorine ion; And

Provided is a zinc-nickel electroplating liquid composition comprising the additive composition for a zinc-nickel electroplating liquid of the present invention.

Hereinafter, the present invention will be described in more detail.

The present invention includes water and an additive in a zinc-nickel electroplating liquid composition, wherein the additive is one or more parts selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, boric acid, and chromic acid, and one part by weight of carboxylic acid having one or more carboxyl groups in its structure. By using the additive composition for zinc-nickel electroplating liquid containing 5 to 10 parts by weight of inorganic acid, the positive electrode has good reactivity and electrodeposition reaction to form a uniform electrodeposition layer, and exhibits excellent plating adhesion and side reactions. Phosphorus hydrogen generation can be minimized.

The carboxylic acid may be used as one having at least one carboxyl group in the structure, without limitation, preferably using an aromatic carboxylic acid such as benzoic acid: C6H5COOH, salicylic acid: C6H4 (OH) COOH, phthalic acid: C6H4 (COOH) 2 good.

The inorganic acid may be used at least one selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, boric acid, and chromic acid, preferably using boric acid, more preferably orthoboric acid (H ₃ BO ₃ ), metaboric acid ( Preference is given to using at least one of HBO ₂ ) or tetraboric acid (H ₂ B ₄ O ₇ ).

It is preferable that the inorganic acid is 5-10 weight part with respect to 1 weight part of carboxylic acids, and, as for the said additive composition for zinc-nickel electroplating liquids, it is more preferable that it is 7-9 weight part. When the inorganic acid is less than 5 parts by weight, the adhesion of the plating layer is not improved. When the inorganic acid is more than 10 parts by weight, surface stripes are generated and whiteness is reduced.

It is preferable that the additive composition for zinc-nickel electroplating solution further contains sulfonic acid or a salt thereof.

The sulfonic acid or salts thereof may be used without limitation, but preferably sodium sulfonate is used. It is preferable that such sulfonic acid or its salt is 1-4 weight part with respect to 1 weight part of said carboxylic acids, More preferably, it is 2-3 weight part. If the sulfonic acid or salt thereof is less than 1 part by weight, burning of the plating layer surface is not suppressed. If the sulfonic acid or salt thereof is more than 4 parts by weight, ion adsorption interference is severe and plating layer adhesion is poor, which is not preferable.

In addition, the additive composition according to the present invention includes at least water and additives, it is preferable to include water and additives in a 1: 0.7 to 1.5 weight ratio. More preferably, 1: 0.5 to 1.2 by weight (water: additives) may be included. At this time, if the weight ratio of the additive to water 1 is less than 0.7, the effect of inhibiting hydrogen generation is small, and the plating efficiency is lowered. If the weight ratio exceeds 1.5, the dissolution of the additive is difficult and streaks are generated on the surface of the plating layer.

The invention also provides zinc ions; Nickel ions; Chlorine ion; And it relates to a zinc-nickel electroplating liquid composition comprising the additive composition for zinc-nickel electroplating liquid of the present invention.

The zinc-nickel electroplating liquid composition preferably contains metal ions (Zn ²⁺ + Ni ²⁺ ) of zinc and nickel at a concentration of 70 to 140 g / L, more preferably at a concentration of 90 to 110 g / L. It is good to include. When the concentration of the metal ions (Zn ²⁺ + Ni ²⁺ ) of zinc and nickel is less than 70 g / L, current efficiency is lowered, and the surface may become black due to hydrogen generation during high current operation due to lack of metal ions, and 140 g When / L is exceeded, adhesiveness of a plating layer is bad and electrodeposition cost becomes high, and it is unpreferable.

In addition, the nickel ion is preferably a concentration ratio (Ni ²⁺ / (Zn ²⁺ + Ni ²⁺ )) of 0.08 to 0.15. If the concentration of nickel ions in the zinc-nickel electroplating solution composition is less than 0.08, the nickel content in the plating layer is low, and the corrosion resistance is lowered. If the nickel-nickel electroplating solution composition is less than 0.15, the nickel content in the plating layer is increased. It is not preferable because it may occur.

The concentration of chlorine ions in the zinc-nickel alloy electroplating solution is preferably 220 to 340 g / L, and more preferably 240 to 300 g / L. If the concentration of the chlorine ion is less than 220g / L, the conductivity is poor, the adhesion of the plating layer is poor, the surface burns black defects appear, the surface solubility of the anode is also poor, if the concentration of more than 340g / L chloride is poor due to precipitation It is unpreferable because there exists a possibility that a surface flaw may arise.

Zinc ions, nickel ions, and chlorine ions included in the zinc-nickel electroplating liquid composition of the present invention are ionized from the salts containing the respective, and their concentration may be adjusted according to the content of the salts containing them.

In addition, the zinc-nickel electroplating liquid composition may control the concentration of the chlorine ion by a chlorine ion concentration regulator, and the chlorine ion concentration regulator may be a metal selected from the group consisting of chlorides of alkali metals and chlorides of alkaline earth metals. Chloride is preferred, and it is preferable to use at least one member selected from the group consisting of potassium chloride, calcium chloride, sodium chloride and ammonium chloride.

In addition, the zinc-nickel electroplating solution composition preferably comprises an additive composition of the present invention in an amount of 0.1 to 6 ml / L.

Specifically, with respect to the zinc-nickel electroplating solution composition 1L, the zinc-nickel electroplating solution additive composition is preferably contained in 0.1 to 6ml. At this time, if the additive composition for the zinc-nickel electroplating solution is less than 0.1ml, the additive effect of the plating composition is less, so that the effect of uniform electrodeposition and roughness burning is less. There is a problem that the adhesion is poor due to the interference of the adsorption of the ions carrying metal.

The present invention also relates to a method for producing a zinc-nickel electroplated steel sheet in which a zinc-nickel electroplating liquid composition of the present invention is plated on a steel sheet.

The zinc-nickel electroplating solution composition is the same as described above.

The plating is preferably carried out under the conditions of pH 3.0 to 5.5, temperature 50 to 70 ℃, current density 40 to 200A / dm ² , relative flow rate 0.5 to 2.5m / sec.

In the plating, the pH of the zinc-nickel electroplating liquid composition is preferably 3.0 to 5.5, more preferably 4 to 4.5. If the pH is less than 3.0 during plating, the plating efficiency is lowered due to hydrogen generation at the cathode, and black comb pattern is generated on the surface of the plating layer. When the pH exceeds 5.5, the formation of hydroxide and contamination of the plating solution are severely generated.

In addition, the temperature of the zinc-nickel electroplating solution composition is preferably 50 to 70 ° C, more preferably 60 to 65. When the plating temperature is less than 50 ℃, the solubility of various salts are lowered, the content of nickel, which is an alloy metal in the plating layer is lowered, if the temperature exceeds 70 ℃ due to evaporation of the plating composition is severe steam generation and equipment corrosion occurs badly.

Further, the current density of the zinc-nickel electroplating solution composition is preferably 40 to 200 A / dm ² , more preferably 80 to 120. If the current density is less than 40A / dm ² during plating, there is a problem that the glossiness of the plating layer is lowered, and nickel is excessively precipitated in the plating layer, and if the current density is increased, the plating speed is increased to improve productivity, but exceeds 200A / dm ² . It is not preferable because a burning phenomenon appears in the lower surface of the plating layer and a problem occurs in the contact between the steel sheet and the current collector.

In addition, the relative flow rate of the plating composition with respect to the steel plate which is the plated body of the zinc-nickel alloy is preferably 0.5 to 2.5 m / sec, more preferably 1 to 1.5. If the relative flow rate is less than 0.5 m / sec, the plating property may deteriorate due to coarsening of the plating crystals and burning of the plating layer, and it is not preferable because the relative flow rate exceeds 2.5 m / sec because it exceeds the practical range.

The present invention also provides a zinc-nickel alloy electroplated steel sheet produced by the above production method.

The zinc-nickel alloy electroplated steel sheet according to the embodiment of the present invention exhibits excellent whiteness, adhesion, burning inhibition and surface roughness.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are only for illustrating the present invention in detail and are not intended to limit the scope of the present invention by these examples.

[Examples 1 to 8 and Comparative Examples 1 to 8]

Sum of zinc ions and nickel ions in the plating solution = 102 g / L, chlorine ions in the plating composition, nickel ions in the plating composition, and the concentration ratio of nickel ions in the plating composition [Ni / (Ni + Zn)] = 0.11 To the zinc ion 1.38 mol / L, nickel ion 0.20 mol / L), an additive composition for a zinc-nickel electroplating liquid composition having the composition shown in Table 1 was added as shown in Table 1 with respect to 1L of the zinc-nickel electroplating liquid composition. The zinc-nickel electroplating solution composition to which the additive composition for zinc-nickel electroplating solution was added was subjected to plating conditions at a temperature of 60 ° C, pH 4.2, a relative flow rate of 1.5 m / sec, and a current density of 100 A / dm ² of the plating composition on the steel sheet. Samples of Examples and Comparative Examples were prepared by applying a plating amount of 30 g / m 2. (However, at the time of burning experiment, the current density was set to 150 A / dm ² )

Edge burning of the zinc-nickel electroplating steel sheet plated using the zinc-nickel electroplating liquid composition prepared according to Examples 1 to 8 and Comparative Examples 1 to 8 by the following method: The plating layer whiteness, adhesion and surface roughness were compared and tested, and the results measured by the above method are shown in Table 1.

(1) edge burning

In the case of ballistics, when burning appeared at the edge part when the current density was 150A / dm ² , it was evaluated as bad, and when it was not shown, it was evaluated as good.

(2) Plating layer whiteness

The whiteness of the plating layer was measured by a color and color difference meter, and evaluated as 70 or more, and less than 70 as a defect.

(3) adhesion

The adhesion of the plated layer was evaluated to be good and the case where the plated layer was not adhered to the tape after the specimen was bent at 120 ° and the tape was adhered to the compressed portion.

(4) surface roughness

The surface roughness of the plated layer was evaluated to be good if the roughness difference between the roughness of the steel sheet after plating and the steel sheet before plating was 0.5 µm or less on the Rmax basis, and poor when exceeding 0.5 µm.

division Additive Composition (Weight Ratio) Additives to plating solution (ml / L) Plating quality Carboxylic acid: boric acid Carboxylic acid: sodium sulfonate Water: additive Edge burning Plating layer whiteness Adhesion surface
Roughness Comparative Example 1 1: 4.5 1: 2 1: 1 2 Bad Bad Bad Bad Example 1 1: 5.0 1: 2 1: 1 2 Good Good Good Good Example 2 1:10 1: 2 1: 1 2 Good Good Good Good Comparative Example 2 1: 10.5 1: 2 1: 1 2 Bad Bad Bad Bad Comparative Example 3 1: 7.0 1: 0.5 1: 1 2 Bad Bad Bad Bad Example 3 1: 7.0 1: 1 1: 1 2 Good Good Good Good Example 4 1: 7.0 1: 4 1: 1 2 Good Good Good Good Comparative Example 4 1: 7.0 1: 4.5 1: 1 2 Bad Bad Bad Bad Comparative Example 5 1: 7.0 1: 2 1: 0.6 2 Bad Bad Bad Bad Example 5 1: 7.0 1: 2 1: 0.7 2 Good Good Good Good Example 6 1: 7.0 1: 2 1: 1.5 2 Good Good Good Good Comparative Example 6 1: 7.0 1: 2 1: 1.6 2 Bad Bad Bad Bad Comparative Example 7 1: 7.0 1: 2 1: 1 0.05 Bad Bad Bad Bad Example 7 1: 7.0 1: 2 1: 1 0.1 Good Good Good Good Example 8 1: 7.0 1: 2 1: 1 6 Good Good Good Good Comparative Example 8 1: 7.0 1: 2 1: 1 6.1 Bad Bad Bad Bad

As shown in Table 1 above, when comparing the plating layers formed in Examples 1 and 2 with the plating liquid additive of the present invention and the plating layers formed in Comparative Examples 1 and 2, boric acid per 1 part by weight of carboxylic acid 5 to 10 parts by weight was found to be excellent in edge burning, whiteness, adhesiveness and surface roughness.

In addition, when comparing the plated layer formed in Examples 3 and 4 with the plated layer formed in Comparative Example 3 and Comparative Example 4, in the case of 1-4 parts by weight of sodium sulfonate in edge burning, whiteness, adhesion and surface roughness It was found to be very good.

Furthermore, when comparing the plating layers formed in Examples 5 and 6 and the plating layers formed in Comparative Examples 5 and 6, edge burning was performed when water and additives were 1: 0.7 to 1.5 by weight (water: additive). ), Whiteness, adhesion and surface roughness was found to be very excellent.

When comparing the plating layers formed in Examples 7 and 8 with the plating layers formed in Comparative Examples 7 and 8, edge burning when the additives were included in the plating liquid composition at a ratio of 0.1 to 6 ml / L (additive / plating liquid composition). (edge burning), whiteness, adhesion and surface roughness was very good.

Claims (13)

Contains water and additives, The additive is based on 1 part by weight of a carboxylic acid having at least one carboxyl group in the structure; 5 to 10 parts by weight of at least one inorganic acid selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, boric acid and chromic acid; And sulfonic acid or salts thereof. An additive composition for a zinc-nickel electroplating solution. The method of claim 1, The additive composition for zinc-nickel electroplating solution, characterized in that the carboxylic acid is an aromatic carboxylic acid. The method of claim 1, The boric acid is at least one of orthoboric acid (H ₃ BO ₃ ), metaboric acid (HBO ₂ ) or tetraboric acid (H ₂ B ₄ O ₇ ), the additive composition for zinc-nickel electroplating solution. delete The method of claim 1, The additive composition for the zinc-nickel electroplating solution is a zinc-nickel electroplating solution additive composition, characterized in that it contains 1 to 4 parts by weight of sulfonic acid or its salt with respect to 1 part by weight of the carboxylic acid. The method of claim 1, The additive composition is an additive composition for zinc-nickel electroplating solution, characterized in that it comprises water and additives in a weight ratio of 1: 0.7 to 1.5 (water: additive). Zinc ions; Nickel ions; Chlorine ion; And A zinc-nickel electroplating solution composition comprising the additive composition for zinc-nickel electroplating solution according to any one of claims 1 to 3, 5 and 6. The method of claim 7, wherein The zinc-nickel electroplating liquid composition is a zinc-nickel electroplating liquid composition, characterized in that it contains a metal ion (Zn ²⁺ + Ni ²⁺ ) of zinc and nickel at a concentration of 70 to 140g / L. The method of claim 7, wherein The zinc-nickel electroplating liquid composition is a zinc-nickel electroplating liquid composition, characterized in that it contains nickel ions in a concentration ratio (Ni ²⁺ / (Zn ²⁺ + Ni ²⁺ )) of 0.08 to 0.15. The method of claim 7, wherein The zinc-nickel electroplating liquid composition is a zinc-nickel electroplating liquid composition, characterized in that containing chlorine ions at a concentration of 220 to 340g / L. The method of claim 7, wherein The zinc-nickel electroplating liquid composition is a zinc-nickel electroplating liquid composition, characterized in that it comprises an additive composition in a content of 0.1 to 6ml / L. A method of manufacturing a zinc-nickel electroplated steel sheet, characterized in that the zinc-nickel electroplating solution composition according to claim 7 is plated on a steel sheet. The method of claim 12, The plating is a method of producing a zinc-nickel electroplated steel sheet, characterized in that the pH is carried out under the conditions of 3.0 to 5.5, temperature 50 to 70 ℃, current density 40 to 200A / dm ² , relative flow rate 0.5 to 2.5m / sec.