KR20010061574A - a method of manufacturing Zn-Ni alloy galvanized steel with good surface roughness, adhesion and formability and composition of electrolyte - Google Patents

Abstract

PURPOSE: A process for preparing the titled alloy steel sheet by adding ammonium chloride and a mixture of sodium salt condensed naphthalene sulfonic acid, sodium sulfate and o-vanillin as an additive to a basic solution is provided. Whereby, the Zn-Ni alloy plated steel sheet has excellent plating layer roughness, adhesion and processability. CONSTITUTION: In a process for producing Zn-Ni alloy plated steel sheet by electroplating under conditions of 0.5 to 2.0 molar concentration of a zinc ion, 0.1 to 0.5 molar concentration of nickel ion, 6.0 to 9.0 molar concentration of a chloride ion, a pH of a plating solution of 2.5 to 4.5, a temperature of the plating solution of 55 to 75deg.C, a current density of 40 to 180A/dm¬2 and a relative speed between the plating solution and the cathode of 0.5 to 2.5m/sec, the ammonium ion of the plating solution is maintained in a concentration of 0.1 to 0.5 mol and a plating solution obtained by adding 0.05 to 5.0g/L o-vanillin to a basic solution is used.

Description

A method of manufacturing Zn-Ni alloy galvanized steel with good surface roughness, adhesion and formability and composition of electrolyte}

The present invention relates to a method for producing a zinc-nickel alloy electrical steel sheet having good plating roughness, adhesion and workability, and a plating solution composition thereof. The present invention relates to a good plating layer roughness, adhesiveness and The present invention relates to an electroplated steel sheet excellent in workability and a plating solution composition thereof.

Conventionally, metal plating on iron has long been used for rust prevention, decoration, and the like. In particular, zinc electroplating has been developed to secure corrosion resistance of steel sheets and has been widely used in fields such as home appliances, automobiles, construction, and the like. However, it is necessary to increase the thickness of the plated layer by using the corrosion resistance in the harsh atmosphere, thereby adversely affects the increase in cost and adhesion, workability, and the like. Therefore, zinc nickel alloy electroplating has been developed to solve this drawback. There are various kinds of zinc-nickel alloy electroplating according to the components of the bath, but the production method of the plating material based on the acid bath is generally widely used. Acidic baths are based on sulfide baths and on chloride baths. Chloride baths have better electrical conductivity than sulfide baths, which enables high current density plating, and are easier to control and less expensive to control than sulfide baths that use insoluble anodes, mainly using soluble anodes. Soluble anodes mainly use zinc and nickel, and typically have more than about 85% zinc. Therefore, uniform solubility of the zinc anode, i.e., no sludge or foreign matter remains on the anode, can produce a good plated product. However, since zinc and nickel have a large potential difference in the chloride plating bath, sludge in the zinc hydroxide system is generated by electroless substitution of nickel on the zinc anode, and the sludge adheres to the surface of the anode, so that the concentration of the plating solution is caused by uneven dissolution of zinc in continuous operation. The change is severe, the plating voltage increases due to the interruption of the energization, the tube on the surface of the plating layer is not uniform, and the surface roughness is uneven due to the electrodeposition nonuniformity. In addition, peeling in the form of sludge causes burning stains on the stripes and both edges of the plating layer, and the adhesion of the plating layer is degraded by the sludge mixing, thereby causing deterioration of workability.

As a conventional technique for solving such defects, Japanese Patent No. 59-211589 discloses adding a portion of ammonium chloride to a plating solution containing a zinc chloride and nickel chloride as a main component of a chloride bath and a lactate, and altering the plating conditions, thereby adhering to the precipitate. Although it was said that effective mixing of precipitated yellowish brown or blue-violet oxides was effectively suppressed, the precipitation of oxides was suppressed up to about 100 hours at first, but there was a drawback that precipitated again during further operation. In addition, there is a method of improving the solubility of the positive electrode by the addition of alcohol as a general method, but the consumption by the volatilization of alcohol is severe by long time use and the adhesion of the plating layer is not improved. According to Japanese Patent JP 93-167094, the addition of an organic compound contained 0.001 to 10 wt% of carbon in the plating layer to improve workability, but has a disadvantage of poor adhesion. In addition, although ammonium ions are added to the plating solution to improve the reactivity of the positive electrode, this also accelerates the release of sludge in the positive electrode, thereby increasing the amount of sludge in the solution. In the above-described Zn-Ni alloy plating described above, an attempt was made to improve the roughness, adhesion, and workability of the coating layer by improving the solubility of the anode. There is a drawback that the plating layer is poor.

The present invention has been made to solve the above problems, and as a plating solution, sodium salt condensed naphthalene sulfonic acie as an ammonium chloride and an additive in a basic solution of zinc chloride and nickel chloride based on potassium chloride. It is an object of the present invention to provide a method for producing an electroplated steel foil having improved roughness, adhesion and processability of a plating layer by adding an appropriate amount of an additive mixed with sodium sulfate and o-vanillin, and a plating solution composition thereof.

In order to achieve the above object, the present invention provides a zinc chloride molar concentration of zinc ions: 0.5 to 2.0 moles, nickel ion molar concentration of nickel chloride: 0.1 to 0.5 moles, a molar concentration of chloride ions of 6.0 to 9.0, a pH of a plating solution: 2.5-4.5, Plating solution temperature: 55-70 ° C., Current density 40-180 A / dm ^2, Chloride bath zinc-nickel alloy, usually electroplated under plating conditions of the plating liquid and the negative flow rate of 0.5-2.5 m / sec In the method for producing an electroplated steel sheet, the concentration of ammonium ions in the plating liquid is maintained at 0.1 to 1.0 mole, and the molar ratio of sodium sulfonate is 1: 0.001 to 0.008, and the sodium sulfonate and sodium sulfate ratio is 1: 0.1 to 0.5. It is characterized by providing a method for producing a zinc-nickel alloy electroplated steel sheet having excellent plating layer roughness, adhesiveness and workability, which are prepared by using a plating solution in which 0.05 to 5.0 g / L of an anianiline is added to the solution.

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

In order to achieve the above object, zinc chloride has a molar concentration of zinc ion of 0.5 to 2.0 moles, a nickel ion molar concentration of nickel chloride of 0.1 to 0.5 moles, and a molar concentration of chloride ion of 6.0 to 9.0, and the pH of the plating solution: Chloride bath zinc-nickel alloy electroplating, usually electroplating under the plating conditions of 2.5 to 4.5, the plating liquid temperature of 55 to 70 ° C, the current density of 40 to 180 A / dm ^2, and the relative flow rates of the plating liquid and the cathode to 0.5 to 2.5 / sec. In the method for producing a coated steel sheet, the concentration of ammonium ions is maintained at 0.1 to 1.0 mol as a substance added to the plating solution, and the molar ratio of sodium sulfonate is 1: 0.001 to 0.008, and the ratio of sodium sulfonate and sodium sulfate is 1: 0.1 to A plating solution in which 0.05 to 5.0 g / L of ovanillin is added to a solution composed of 0.5 improves the physical properties of the plating material.

Hereinafter, the present invention will be described in detail.

Zinc ions in the plating solution cause burning blacking due to lack of layer metal ions in the plating at a molar concentration of 0.5 mol or less, and at 2.0 mol or more, the plating layer becomes powder-type plating, resulting in poor adhesion. Nickel is less than 10% of the nickel content in the alloy of the plated layer at a molar concentration of 0.1 mol or less, and corrosion resistance is lowered, and at a molar concentration of 0.5 mol or more, the nickel content of the plated layer is 16% or more, resulting in poor workability and corrosion resistance. When the amount of chloride ions is 6.0 mol or less, a large amount of burning occurs due to a decrease in electrical conductivity, and at 9.0 mol or more, chloride ions are precipitated due to solubility problems. Ammonium salt has a large amount of sludge which makes it difficult to perform continuous plating operation at a molar concentration of 0.1 mol or less, and a black film is generated at the anode at 1.0 mol or more, contaminating the plating solution and inferior in adhesion.

When the temperature of the plating solution is 55 ° C. or lower, the color of the plating layer is dark and the adhesion of the plating layer is inferior, resulting in peeling phenomenon. When the temperature of the plating layer is 70 ° C. or more, the plating streaks are severe and the roughness of the plating layer is poor. When the pH of the plating solution is 2.5 or less, the plating surface becomes dark and semi-gloss, and when the plating solution is contaminated by sludge of impurity ions dissolved in the solution, the pH is preferably limited to 1.5 to 5.5.

If the concentration of sodium sulfonate is less than 0.001 compared to the ammonium mole, it is impossible to suppress the sludge of the anode film during operation, so that the roughness and adhesion of the coating layer cannot be improved. Is generated. When the ratio of sodium sulfate to sodium sulfate is less than 0.1, the surface appearance becomes yellow and roughness is not improved, and above 0.5, the adhesion is reduced. When the concentration of the o-vanillin is 0.05 g / L or less, the workability of the plated layer is not improved, and at 5.0 g / L or more, the adhesion is reduced.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example)

5 days (120 hours) in a continuous operation of a solution having the plating solution composition shown in Table 1 below using a cold rolled steel sheet as a base metal, and then electroplating the solution after plating for 4 hours continuously as a positive electrode reactivity test device. The turbidity was measured, and the coating amount was plated at 30 g / m ² to evaluate the quality of the product. In addition, the plating adhesion was poor when the peeled plating layer on the tape was seen due to the peeling amount of the plating layer deposited on the tape after bending at 120 °. In addition, the machinability showed that the friction coefficient was less than 0.13 after application of antirust oil by a single-side friction tester, and more than that was poor.

division Plating solution Additive condition Plating quality Zn ^{2 =} Cl ^- NH ^{4 =} NH: sodium sulfonate (molar ratio) Sodium sulfonate: Sodium sulfate (molar ratio) O-Vanyl Amount (g / L) Plating solution turbidity NTU Roughness Machinability Plating Peelability Comparative example One 1.1 0.15 6.5 0.8 1: 0.00 0: 0 0.5 1.0 Bad Bad Bad Comparative example 2 1: 0.0005 1: 0.3 0.5 0.9 Bad Bad Bad Inventive Example 3 1: 0.001 1: 0.3 0.5 0.3 Good Good Good Inventive Example 4 1: 0.005 1: 0.3 0.5 0.2 Good Good Good Inventive Example 5 1: 0.008 1: 0.3 0.5 0.1 Good Good Good Comparative example 6 1: 0.01 1: 0.3 0.5 0.2 Bad Bad Good Comparative example 7 1: 0.005 1: 0.00 0.5 0.4 Bad Bad Good Comparative example 8 〃 1: 0.05 0.5 0.1 Bad Bad Good Inventive Example 9 〃 1: 0.1 0.5 0.2 Good Good Good Inventive Example 10 〃 1: 0.3 0.5 0.2 Good Good Good Inventive Example 11 〃 1: 0.5 0.5 0,3 Good Good Good Comparative example 12 〃 1: 0.6 0.5 0.1 Good Bad Bad Comparative example 13 〃 1: 0.3 0.04 0.1 Bad Bad Bad Inventive Example 14 〃 0.05 0.3 Good Good Good Inventive Example 15 〃 0.1 0.2 Good Good Good Inventive Example 16 〃 0.5 0.2 Good Good Good Inventive Example 17 〃 1.0 0.3 Good Good Good Inventive Example 18 〃 3.0 0.1 Good Good Good Inventive Example 19 〃 5.0 0.2 Good Good Good Comparative example 20 〃 5.1 0.3 Good Bad Bad

As shown in Table 1, the invention example consistent with the present invention shows that the plating liquid is cleaned and the roughness, adhesion and workability are good.

As described above, the present invention shows an excellent effect on the zinc-nickel plating quality in the chloride-based plating solution.

Claims (2)

Zinc chloride molar concentration of zinc ion: 0.5-2.0 mol, nickel ion molar concentration of nickel chloride: 0.1-0.5 mol, molar concentration of chloride ion 6.0-9.0, pH of plating liquid: 2.5-4.5, temperature of plating liquid: 55- In the method for producing a zinc chloride-nickel alloy electroplating steel sheet, which is usually electroplated at a plating condition of 70 to 180 A / dm ² , a current density of 40 ° C., and a relative flow rate of the plating solution and the cathode to 0.5 to 2.5 m / sec. The concentration of ammonium ions in the plating solution was maintained at 0.1 to 1.0 mole, and the molar ratio of sodium sulfonate was 1: 0.001 to 0.008, and the solution of obaniline was 0.05 to 5.0 in a solution having a sodium sulfonate and sodium sulfate ratio of 1: 0.1 to 0.5. A method of manufacturing a zinc-nickel alloy electroplated steel sheet having excellent plating layer roughness, adhesiveness, and workability, which is prepared using a plating solution added with g / L. Zinc chloride molar concentration of zinc ion: 0.5-2.0 mol, nickel ion molar concentration of nickel chloride: 0.1-0.5 mol, molar concentration of chloride ion 6.0-9.0, pH of plating liquid: 2.5-4.5, temperature of plating liquid: 55- In a plating solution for producing a zinc-nickel alloy electroplated steel sheet at a plating condition of 70 DEG C, a current density of 40 to 180 A / dm ² and a relative flow rate of the plating liquid and the cathode of 0.5 to 2.5 m / sec, the ammonium ion of the plating liquid The concentration was maintained at 0.1 to 1.0 mole, and the molar ratio of sodium sulfonate was 1: 0.001 to 0.008, and 0.05 to 5.0 g / L of obaniline was added to the solution composed of 1: 0.1 to 0.5 ratio of sodium sulfonate and sodium sulfate. Plating liquid composition, characterized in that.