KR19980053469A - Zinc-nickel alloy electroplating solution and electroplating method using the same - Google Patents

Abstract

The present invention relates to a plating solution in which the zinc ion concentration of zinc chloride is 20-150 g / l, the nickel ion concentration of nickel chloride is 0.1-15 g / l, and the chlorine concentration is 100-300 g / l (solution). , A solution in which the aryl alcohol and the propazyl alcohol are 1: 1 by mass ratio, 10 to 25% of saccharin, 8 to 20% of surfactant, and water as a balance factor by mass ratio of 0.1 mol / L to 0.1 mol / L additive at 5 mmol / L. The zinc-nickel alloy electroplating solution formed by adding 0.2-2.0ml / L in a concentration, and the zinc-nickel plating solution described above, pH 1.5-4.5, the temperature of the plating solution 50-70 ° C., the current density 20 The present invention relates to a method for producing a zinc-nickel alloy electroplated steel sheet by electroplating 180 A / dm ² and the relative flow rates of the plating solution and the cathode under plating conditions of 0.5-2.5 m / sec.

Description

Zinc-nickel alloy electroplating solution and electroplating method using the same

The present invention relates to a plating method for suppressing sludge of a solution generated during zinc nickel alloy electroplating and producing a good plating layer on a steel sheet.

Electroplating metal plating has long been used for rust prevention and decoration. Zinc electroplating has been developed to secure corrosion resistance of double steel sheets and has been widely used in fields such as home appliances, automobiles, and construction. In order to secure corrosion resistance under severe atmosphere, the thickness of the galvanized layer should be increased, which adversely affects the increase in cost, adhesion, and workability. Therefore, zinc, nickel alloy electroplating has been developed to solve this drawback. Zinc-nickel alloy electroplating is various depending on the components of the bath, of which the plating material production method based on the acid bath is generally widely used. Acid baths include sulfide baths as basics and chloride baths as basics. Chloride baths have better electrical conductivity and higher current density plating than sulfide baths, and solution control is easier and less expensive than sulfide baths using insoluble anodes, mainly using soluble anodes. Soluble anodes are predominantly zinc and nickel, with zinc in excess of about 80%. However, in the chloride bath where soluble zinc is used, the surface quality of the plated product is poor due to sludge or foreign substances generated in the solution during plating. Sludge or foreign substances present in the plating solution on the surface of the turning roll to change direction are moved through the steel plate.

In order to solve such a defect, conventionally, the acidity (ph) of the plating liquid was lowered to suppress sludge generation. However, when the pH of the zinc-nickel plated is less than 1.5, the plating material is hardened by hydrogen generation. -211589) adds some ammonium chloride to a plating solution containing zinc chloride and nickel chloride as a main component of a chloride bath and lactate, and changes the plating conditions to effectively prevent the precipitation of yellow-brown or blue-violet oxides accompanying incident materials. Sludge generation is suppressed at the beginning of operation, but sludge is generated over time. In addition, US Patent (428580,4388160) and the like relates to an additive for improving the surface glossiness does not improve the cleanliness of the plating liquid.

The present invention is to solve the problems of the prior art, the present invention is to provide an electroplating solution and a plating method for suppressing the sludge of the solution generated during zinc nickel alloy electroplating to form a good plating layer on a steel sheet For that purpose.

The object of the present invention is to ensure that the zinc ion concentration of zinc chloride is 20-150g / l, the nickel ion concentration of nickel chloride is 0.1-15g / l, and the chlorine concentration is 100-300g / l (solution). For the plating solution, a solution in which the aryl alcohol and the propazyl alcohol are 1: 1 by mass ratio is 10-25% of saccharin, 10-20% of surfactant, 8-20% of surfactant, and a balance factor by mass ratio of 0.1 mol / L additive at 5 mmol / L. The pH of the plating solution was measured using a zinc-nickel (En-Ni) electroplating solution formed by adding 0.2-2.0 ml / L to water containing water as the above, and the zinc-nickel plating solution described above. It is achieved by the method of producing zinc-nickel alloy electroplating sheet by electroplating at 50-70 ℃, current density of 20-180A / dm ² and relative flow rate of plating solution and cathode under plating condition of 0.5-2.5m / sec. .

Hereinafter, the present invention will be described.

In the aqueous plating bath, the concentration of the metal zinc as the zinc chloride compound is 20-150 g / L (solution) and more preferably 50-90 g / L (solution). As the nickel chloride compound, the concentration of metal nickel is 5-10 g / L (solution). As an electrolyte, it is a chloride such as potassium chloride, calcium chloride, sodium chloride, ammonium chloride, etc., and one or two or more thereof, which has a chlorine concentration of 100-300 g / L (solution), and more preferably 200-280 g / L (solution). Let this be. The additive prepared according to the present invention should be added at 0.2-2.0 ml / L, but preferably 0.4-1.5 ml / L. In the above plating bath composition, the zinc-nickel electroplated steel sheet is manufactured at a temperature of 50-70 ° C., PH 1.0-4.5, a current density of 20-180 A / dm ² , and a relative flow rate of 0.5-2.5 m / sec.

Additive Composition and Range Reasons

The additive is prepared by adding a solution of aryl alcohol (Ch ₂ ChCh ₂ ) and propazyl alcohol (Ch ₃ Ch ₄ O) in a solution of saccharin (sodium salt hydrate) and surfactant completely dissolved in a certain ratio. do. The surfactant is composed of a group 1 element salt of a substance in which naphthalene has a sulfonic group and condensation reaction with formaldehyde, and has the following structures (a), (b) and (c).

[Formula]

Where M is a group 1 element such as Na, K, etc.

Additive ratio is 10 percent by weight saccharin 25 percent with 8 surfactants 20 percent, balance factor, the remainder consisting of water, and 0.1 mol / liter (0.1 mol / L) at 5 milliliters / liter (5 mol / L) of aryl alcohol and propazyl alcohol in a mass ratio of 1: 1. It is formed by addition. Outside of each ratio and section, the quality of surface appearance and roughness will be poor during plating operation.In particular, alcohol has no effect on removing sludge or foreign substances from plating solution at less than 1.0mmol and surface appearance at 0.1mol or more. This becomes poor.

Reasons for Limiting Plating Bath and Plating Conditions

When the concentration of the metal zinc is less than 20g / L, the electrodeposition efficiency is poor, and when the concentration of the metal zinc is more than 150g / L, the solubility of the zinc compound is bad and the electrodeposition cost is high. If the amount of metal nickel is 0.1g / L or less, the desired alloy plating can not be produced, and at 15g / L or more the low-temperature chipping resistance required for automotive steel sheet is reduced and the corrosion resistance is poor. If the concentration of chlorine is less than 100g / L, the conductivity is poor, the adhesion of the plating layer is poor, the surface burns black defects, and above 300g / 1, the solubility of chloride compounds is poor. If the concentration of the additive is less than 0.2ml / L, the sludge of the plating solution during the plating operation is not suppressed, the plating surface appearance is poor due to the additive at the concentration of 0.2ml / L or more. In addition, when the temperature is 50 ℃ or less, the solubility of various salts is lowered, the content of nickel, which is an alloy metal of the plating layer is lowered, and at 70 ℃ or more due to the evaporation of the plating solution, the generation of steam is severe and the equipment corrosion occurs badly. If the pH is less than 1.5, the plating efficiency is lowered due to hydrogen generation at the cathode, and the comb-tooth pattern is generated on the surface of the plating layer. At 4.5 or more, generation of hydroxide and the like and contamination of the plating solution are severely generated. When the relative flow velocity of the plating liquid on the steel plate, which is the zinc-nickel alloy plated body, is 0.5 m / sec or less, the plating property is deteriorated due to coarsening of the plating crystals and burning of the plating layer. Is beyond the interval. If the current density is 20 A / dm ² or less, the glossiness of the plating layer is lowered, and the defect of over-precipitation of nickel in the plating layer appears. However, as the current density increases, the plating speed is increased, and the productivity is improved. However, when the current density is 180 A / dm ² or more, a burning phenomenon appears in the plating layer and a problem occurs in the contact between the steel sheet and the current collector.

Hereinafter, an embodiment of the present invention will be described.

Table 1 shows the plating solution concentration and plating conditions. Indicated. The whiteness of the plated steel sheet was measured as a color and color difference meter, the glossiness as a gloss meter, and the cleanness of the plating liquid was expressed as turbidity after 4 hours of operation.

Plating condition of zinc-nickel electroplating Plating solution composition (g / L) Coating Weight (g / m ² ) ph Temperature (℃) Flow rate (m / sec) Current density (A / dm ² ) Zn Ni Cl 80 12 280 30 2.5 61 1.5 100

Among the components of the additive of the present invention, the saccharin sodium salt is 10-25%, the surfactant is 8-20%, and the aryl alcohol: propazyl alcohol = 1: 1 is added to the invention in the range of 0.05 mol-1.0 mol / liter. Good at 2.0 ml / L (3-5, 8-11, 15-17, 20-23) and outside of the above range (1-2, 6-7, 12-14, 17-19, 24 Excellent surface quality and cleanliness of the plating solution were shown.

As described above, according to the present invention, a zinc-nickel alloy electroplating product can be produced in a zinc-nickel alloy electroplating bath that can maintain a good degree of plating liquid and have a good surface quality of the plating layer.

Surface quality and nickel deposition rate of zinc-nickel electroplating materials Plating Material Good No Additive component (mass%) Additive amount (ml / L) Plating agent quality Saccharin Sodium Surfactants Alcohol level (water / liter) Whiteness Glossiness Cleanness of Plating Solution One compare One 15 0.05 0.5 Bad Bad Good 2 5 15 0.05 0.5 Bad Good Good 3 invent 10 15 0.05 0.5 Good Good Good 4 20 15 0.05 0.5 Good Good Good 5 25 15 0.05 0.5 Good Good Good 6 compare 30 15 0.05 0.5 Bad Bad Good 7 20 5 0.05 0.5 Bad Bad Good 8 invent 20 8 0.05 0.5 Good Good Good 9 20 10 0.05 0.5 Good Good Good 10 20 15 0.05 0.5 Good Good Good 11 20 20 0.05 0.5 Good Good Good 12 compare 20 22 0.05 0.5 Bad Bad Good 13 20 25 0.05 0.5 Bad Good Good 14 20 15 0.001 0.5 Good Bad Bad 15 invent 20 15 0.005 0.5 Good Good Good 16 20 15 0.01 0.5 Good Good Good 17 20 15 0.1 0.5 Good Good Good 18 compare 20 15 0.11 0.5 Good Bad Bad 19 20 15 0.05 0.1 Bad Bad Good 20 invent 20 15 0.05 0.2 Good Good Good 21 20 15 0.05 0.5 Good Good Good 22 20 15 0.05 1.0 Good Good Good 23 20 15 0.05 2.0 Good Good Good 24 compare 20 15 0.05 2.5 Bad Bad Good

Whiteness (less than 68: poor, more than 68: good), glossiness (less than 72: poor, more than 72: good)

Accuracy (under turbidity 2.0 NTU: good, turbidity above 2.0 NTU: poor).

According to the present invention, it is possible to suppress the sludge of the solution generated during the zinc-nickel alloy electroplating, to maintain a good degree of the plating solution in the zinc-nickel alloy electroplating bath, the zinc-nickel alloy with good surface quality of the plating layer Electroplating products can be prepared.

Claims (2)

Aryl alcohol for a plating solution in which the zinc ion concentration of zinc chloride is 20-150 g / l, the nickel ion concentration of nickel chloride is 0.1-15 g / l, and the chlorine concentration is 100-300 g / l (solution). And a solution in which the proportion of propazyl alcohol is 1: 1 in a mass ratio of 10 to 25% of saccharin, 8 to 20% of a surfactant, and water as a balance factor at a mass ratio of 0.1 mol / L to 0.1 mol / L additive at 5 mmol / L. A zinc-nickel alloy electroplating solution formed by adding 0.2-2.0 ml / L to the solution. Using the zinc-nickel plating liquid of claim 1, the plating is performed at pH 1.5-4.5, the temperature of the plating liquid is 50-70 ° C., the current density is 20-180 A / dm ^2, and the relative flow rates of the plating liquid and the cathode are 0.5-2.5 m / sec. A method of producing a zinc-nickel alloy electroplated steel sheet by electroplating under conditions.