KR101367912B1 - Plating method using the Tin-Zinc alloy plating solution - Google Patents

Abstract

The present invention relates to a plating method using a tin-zinc alloy plating solution, and more specifically, nicotinic acid and cocamidopropyl betaine are added to an electrolyte solution consisting of tin and zinc during surface treatment of rust-preventing materials commonly used in automobiles and constructions. In order to suppress the variation of the low current site plating layer, and in particular, to add a positive electrode sludge and to suppress the increase of the current value, the ethylenediaminetetraacetic acid-4 sodium salt and glycerin are added to secure a uniform plating layer of the low current site. The present invention relates to a plating method using a tin-zinc alloy plating solution.

Description

Plating method using the Tin-Zinc alloy plating solution

The present invention relates to a plating method using a tin-zinc alloy plating solution, and more specifically, nicotinic acid and cocamidopropyl betaine are added to an electrolyte solution consisting of tin and zinc during surface treatment of rust-preventing materials commonly used in automobiles and constructions. In order to suppress the variation of the low current site plating layer, and in particular, to add a positive electrode sludge and to suppress the increase of the current value, the ethylenediaminetetraacetic acid-4 sodium salt and glycerin are added to secure a uniform plating layer of the low current site. The present invention relates to a plating method using a tin-zinc alloy plating solution.

As regulations on lead in dust generated from automobile scrapping around the world are tightened, there is an increasing need for lead-free steel sheets that can replace molten Terne steel sheets in use.

As a result, technologies such as molten aluminum plated steel sheets, zinc resin coated steel sheets, and special post-treatment having plated materials are being developed.

Among them, tin-zinc plating can be divided into hot dip plating and electroplating. In order to ensure excellent corrosion resistance, a zinc concentration range of 10 to 30% should be included in the plating layer.

However, due to the large deposition potential difference between tin and zinc during electroplating, high current density plating is difficult and seam weldability is poor.

In this regard, Japanese Patent Application Laid-Open No. 08-325692 discloses a tin-zinc plated hot dip coating material, but the tin-zinc hot dip plated disclosed in the above-described patent is difficult to control the thickness of the plated layer to ensure uniformity. Since there is no support, there is a problem in that workability and weldability are poor.

In addition, Japanese Patent No. 4445526 discloses tin added with a surfactant such as carboxy betaine, sulfo betaine, imidazoline betaine, aminocarboxylic acid, or the like to improve the appearance, compactness, smoothness, and adhesion of the plated film. Although an aliphatic sulfonic acid plating bath of a tin alloy has been disclosed, there is a problem that the above-described configuration also has difficulty in securing uniformity due to difficulty in controlling the thickness of the plating layer.

The present invention has been made to solve the problems of the prior art as described above, the object of the present invention is nicotinic acid and cocamidopropyl in the electrolyte consisting of tin and zinc during the surface treatment of rust-preventive materials commonly used such as automobiles and construction The present invention provides a plating method using a tin-zinc alloy plating solution capable of suppressing low current site plating layer variation by adding betaine.

In addition, the present invention by adding ethylenediaminetetraacetic acid-4sodium salt and glycerin in order to secure the plated layer of the low-current site in order to produce a positive electrode plate sludge affecting the thickness of the plated layer and to suppress the increase in current value tin-zinc Another object is to provide a plating method using an alloy plating solution.

In addition, the present invention provides a plating method using a tin-zinc alloy plating solution in which plating on a material susceptible to acids or alkalis such as ceramic composite parts is possible, and the coating layer of the plating layer has corrosion resistance against salt spray, sulfurous acid gas, and the like. There is another purpose in providing.

In addition, the present invention has another object to provide a plating method using a tin-zinc alloy plating solution to improve the corrosion resistance of the coating layer by applying a neutralization treatment, room temperature standing, hot water washing, etc., which is not applied in the conventional tin plating process. .

Plating method using a tin-zinc alloy plating solution according to the present invention for achieving the above objects,

In a plating method using a tin-zinc alloy plating solution, a degreasing step for degreasing the surface of a metal material to be plated, a first hot water washing step of washing a dehydrated metal material in a 60 ° C hot water, and a hot water washing step An acid treatment step of acid treatment of the metal material after use with hydrochloric acid having a concentration of 20% at a percentage concentration, a first activation step of activating the metal material after acid treatment, and plating of an activated metal material using a tin-zinc alloy plating solution A tin-zinc plating step, a second activation step of activating the metal material after the plating operation, a chromate step of coating an anti-rust coating on the surface of the activated metal material, and a metal material of the anti-rust treatment in a hot water at 50 to 70 ° C. Characterized in that comprises a second hot water washing step to wash.

At this time, after the acid treatment step, characterized in that it further comprises a chemical polishing step of polishing the surface of the metal material.

In addition, after the chemical polishing step, characterized in that it further comprises a neutralization step of neutralizing the chemically polished metal material.

And, after the chromate step, the room temperature leaving step of leaving the rust-treated metal material at room temperature for 20 to 40 seconds, characterized in that it further comprises.

In addition, the degreasing step, the immersion degreasing step of immersing the metal material in the degreasing solution to first degrease the surface of the metal material, and the second degreasing of the surface of the metal material by immersing the first degreasing metal material in the electrolyte solution It characterized in that the electrolytic degreasing step.

According to the present invention, nicotinic acid and cocamidopropyl betaine are added to the electrolyte consisting of tin and zinc in the surface treatment of rust-preventing materials generally used in automobiles and constructions, thereby suppressing low current site plating layer variation, and particularly in the thickness of the plating layer. Ethylenediaminetetraacetic acid-4sodium salt and glycerin can be added to prevent positive electrode sludge formation and to suppress the increase in current value, so that a uniform plating layer at a low current portion can be secured, thereby improving workability and weldability. .

Further, according to the present invention, plating on a material susceptible to acid or alkali, such as a ceramic composite component, is possible, and the coating layer of the plating layer further has an effect of having corrosion resistance against salt spray, sulfurous acid gas, and the like.

In addition, according to the plating method using a tin-zinc alloy plating solution according to the present invention, by further applying a process such as neutralization treatment, room temperature standing, hot water washing, which is not used in the existing plating process to improve the corrosion resistance of the plating layer. It further has an effect.

In addition, the present invention further has an excellent effect of improving corrosion resistance by about 10 times or more as compared with conventional general tin plating.

In addition, according to the present invention can be used as a substitute for zinc-nickel alloy plating using imported chemicals, not only to reduce the manufacturing cost, but also to work in white and black color as a substitute for general galvanized It further has a usable effect.

In addition, the present invention can be applied to a variety of industries, such as construction, electrical, electronics, and in particular has an additional effect that can be widely used in electronic parts that require solderability and weldability, and automobile parts that consider corrosion resistance.

1 is a flow chart sequentially showing a plating method using a tin-zinc alloy plating solution according to the present invention.

Hereinafter, exemplary embodiments of a plating method using a tin-zinc alloy plating solution according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart sequentially showing a plating method using a tin-zinc alloy plating solution according to the present invention.

The present invention is to add the nicotinic acid and cocamidopropyl betaine to the electrolyte consisting of tin and zinc in the surface treatment of rust-preventive materials commonly used in automobiles and constructions to suppress the low current site plating layer variation, in particular affect the thickness of the plating layer The present invention relates to a plating method using a tin-zinc alloy plating solution that ensures a uniform plating layer at low current sites by adding ethylenediaminetetraacetic acid-4sodium salt and glycerin to prevent sludge formation and increase of current value. The composition of the tin-zinc alloy plating solution used in the present invention mainly includes nicotinic acid and cocamidopropyl betaine.

In more detail, the present invention is characterized in that a tin-zinc alloy plating solution is added by adding nicotinic acid and cocamidopropyl betaine as an additive to a conventional electrolyte solution including tin and zinc, wherein the nicotinic acid is a carboxyl-based aromatic As a compound, it reacts with the conductive salt of sulfuric acid type and the chlorine type metal component to precipitate zinc on the low current side, as well as smoothing at low current, thereby suppressing the variation of plating layer at low current. Will be

Next, the cocamidopropyl betaine is present in the form of an amphoteric surfactant to smooth the high current tin-zinc precipitation in aqueous solution and to form an alloy ratio at high current.

That is, the present invention adds nicotinic acid and cocamidopropyl betaine as an additive to a conventional electrolyte solution containing tin and zinc, so that smoothing at low current and high current is smoothly performed, and plating layer deviations are generated at low current sites. It is characterized by making it possible to ensure an even plating layer as a whole.

Next, the tin-zinc alloy plating solution according to the present invention may further comprise ethylenediaminetetraacetic acid-tetrasodium salt, wherein the ethylenediaminetetraacetic acid-tetrasodium salt is a complexing agent and a metal. It is characterized by the fact that it has the property of tissue blockage, and it prevents sludge from forming in the plating solution positive electrode plate by losing the property of metal ions, and reverses the increase in the current value of the plating solution to secure a uniform plating layer at low current sites. It will play the role of making it possible.

In addition, the tin-zinc alloy plating solution according to the present invention may further comprise a glycerin (Glycerin), the glycerin serves as a complexing agent for increasing the solubility of the tin salt is also more uniform plating layer at a low current site It is to play a role to secure the.

성분으로 존재하는 것으로, 후술할 시트르산 및 25% 수산화암모늄(암모니아수)에 대비한 유기산 주석의 투입량에 따라 도금수용액의 탁도에 영향을 미치게 된다.Meanwhile, the tin-zinc alloy plating liquid according to the present invention will be described in more detail, including organic acid tin, zinc chloride, citric acid, 25% ammonium hydroxide, boric acid, ammonium sulfate, disodium laureth sulfosuccinate and nicotinic acid. First, the organic acid tin (Stannous Methane Sulfonate Solution) is an aqueous solution

By being present as a component, it affects the turbidity of the plating solution according to the amount of organic acid tin prepared in the citric acid and 25% ammonium hydroxide (ammonia water) to be described later.

At this time, as shown in Table 1 below, when the content of the organic acid tin is 1.0 g / L or less, the workability and plating appearance is poor and the precipitation of tin at low current plating is not good, the content of organic acid tin is 5.0 In the case of g / L or more, the turbidity of the plating solution becomes poor, so the content of the organic acid tin is preferably 1.0 to 5.0 g / L. (Hereinafter, g / L used in the present invention is dissolved per 1 L of water. In the present invention, a to b mean more than a but less than b.)

In addition, as shown in Table 1 below, when the content of the organic acid tin is 3.0 ~ 3.5 g / L it can be seen that the low current tin-zinc alloy ratio and the plating quality state is the optimal state.

Next, zinc chloride (Zinc chloride) is present in the form of Zn metal powder in the form of chloride in an aqueous solution state, and affects the processability by Zn (zinc) precipitation.

As a result of the test, when the content of zinc chloride is 5.0 g / L or less, it was confirmed that zinc was not easily precipitated at low current plating, and burning plating was formed at high current, and the content was more than 50 g / L. It was confirmed that the plating of the dark color as a whole during the low current plating.

In addition, as shown in Table 2 below, when the zinc chloride content is less than 15 g / L, the workability is poor, when the content is more than 40 g / L, the workability and appearance of the plating is not good, so the content of zinc chloride Silver is preferably from 15 to 40 g / L, more preferably from 30 to 35 g / L.

Next, the citric acid and 25% ammonium hydroxide (ammonium hydroxide) were added to the plating solution according to the introduction of the organic acid tin according to the ratio relationship (1: 0.9 to 1) of ammonia water in the alloy aqueous solution as described above. In the case of citric acid, as shown in Table 3 below, when the content is 90 g / L or less, or 150 g / L or more, the overall plating quality including the turbidity of the plating solution is poor. You can check it.

Therefore, the content of the citric acid is preferably included as much as 90 ~ 150 g / L, more preferably the content of citric acid is 90 ~ 100g / L are all good in the turbidity, peelability, processability, plating appearance state of the plating solution.

In addition, the 25% ammonium hydroxide is preferably included as much as 80 ~ 140 g / L, because the content of the 25% ammonium hydroxide is less than 80 g / L, or 140 g, as shown in Table 4 below If / L or more, the overall plating quality including the turbidity of the plating solution is poor.

At this time, the most preferable content of 25% ammonium hydroxide is 90 to 100 g / L.

Next, the boric acid (Boric acid) is not a factor directly affecting the plating, but acts as a PH buffer due to the buffer mechanism.

That is, the boric acid acts as an alkali when the plating liquid is acidified, and acts as an acid when the plating liquid is alkalinized, thereby acting as a buffer for the PH change of the plating liquid.

At this time, the content of the boric acid is contained 15 to 50 g / L, more preferably as much as 25 to 40 g / L, the reason is, as shown in Table 5 below, the content of boric acid is 25 to 40 g / L This is because the change in PH is the smallest in continuous operation and the most efficient in terms of plating quality.

On the other hand, when the boric acid content is less than 10 g / L, or more than 50 g / L, it was confirmed that the pH change during the continuous operation is rapidly increased, which is not suitable for the quality of the plating.

Next, the ammonium sulfate (Ammonium Sulfate) is well dissolved in water and dissociates into ammonium ions and sulfate ions in the plating solution to show weak acidity, and interacts with disodium laureth sulfosuccinate, which will be described later, low current portion It is added to facilitate tin precipitation.

At this time, the ammonium sulfate is preferably so that the content is 40 ~ 60 g / L, the reason is that when the content of ammonium sulfate is less than 40 g / L it is difficult to plate at a high current density, the content is 60 g It is because the color of the plating layer surface turns brown when / L or more.

Next, the disodium laureth sulfosuccinate is an anionic surfactant that serves to form a low current zinc precipitation action and tin-zinc smoothing from medium current to low current in an aqueous solution.

At this time, the disodium laureth sulfo succinate preferably has a content of 1.0 to 10 g / L, because the reason is that when the content is less than 1.0 g / L, low current zinc precipitation does not occur, If the content is 10 g / L or more, as shown in Table 6, because the overall plating quality including workability is deteriorated.

In addition, the content of the most preferable disodium laureth sulfosuccinate is 2.0 to 5.0 g / L.

Next, as described above, nicotinic acid precipitates low current side zinc and smoothes at low current, and the content is preferably 0.1 to 0.6 g / L.

That is, when the content of nicotinic acid is 0.1 g / L or less, the above-described effect of nicotinic acid does not appear well, and when the content is 0.6 g / L or more, as shown in Table 7 below, overall plating quality including the peelability This is because it is degraded.

At this time, the most preferable content of nicotinic acid is 0.3 ~ 0.5g / L.

On the other hand, the cocamidopropyl betaine contained in the tin-zinc alloy plating solution according to the present invention is preferably such that the content is 1.0 to 10 g / L, the reason is that the burning plating phenomenon when the content is 1.0 g / L or less This occurs because tin-zinc precipitation does not easily occur at high currents, and a phenomenon in which the composition of the plating liquid becomes uneven due to a rise in temperature due to voltage / current rise occurs.

In addition, when the content of the cocamidopropyl betaine is 10 g / L or more, as shown in Table 8 below, the quality of the overall plating including the workability is reduced, and the precipitation effect of tin-zinc deteriorates due to the saponification of the surfactant. Because.

At this time, as shown in Table 8 below the most preferred content of cocamidopropyl betaine is 2.0 ~ 5.0g / L.

Next, the ethylenediaminetetraacetic acid-4 sodium salt contained in the tin-zinc alloy plating solution according to the present invention, as described above, loses the property of metal ions, thereby suppressing the formation of sludge in the plating solution positive electrode plate, By reversing the increase in the current value serves to ensure a uniform plating layer in the low current site, the content is 1.0 ~ 5.0 g / L.

That is, when the content of the ethylenediaminetetraacetic acid-4 sodium salt is 1.0 g / L or less, the above-described effect is not well observed, and when the content is 5.0 g / L or more, as shown in Table 9 below, peelability and processability This is because the quality of the overall plating, including the deterioration.

At this time, the content of the most preferred ethylenediaminetetraacetic acid-4 sodium salt in the present invention is 4.0 ~ 4.5 g / L.

Finally, the glycerin contained in the tin-zinc alloy plating solution according to the present invention is an anionic surfactant, which complements the above-mentioned disodium laureth sulfosuccinate, thereby reducing the electrical resistance of the plating, and in the low current portion. By facilitating the penetration of the plating, and serves as a complexing agent for increasing the solubility of the tin salt, it also serves to ensure a more uniform plating layer at low current sites, the content is 1.0 ~ 5.0 g / L is included.

Therefore, the components and contents of the tin-zinc alloy plating solution according to the present invention configured as described above are shown in Table 10 below.

As shown in Table 10, the pH of the completed tin-zinc alloy plating solution (plating bath) is almost neutral at 5.8 to 6.2, specific gravity is 11 to 13, and is used at a temperature of 30 to 40 ° C.

Meanwhile, in the plating method using the tin-zinc alloy plating solution according to the present invention, a degreasing step (S10), a first hot water washing step (S20), an acid treatment step (S30), and a first activation step ( S60), tin-zinc plating step (S70), the second activation step (S80), chromate step (S90) and the second hot water washing step (S110) comprises a first, the degreasing step (S10) to be plated It serves to remove the oil component present on the surface of the metal material, which is composed of an immersion degreasing step (S12) and an electrolytic degreasing step (S14).

In more detail, the deep cleaning step (S12) serves to degrease the surface of the metal material primarily by immersing the metal material to be plated in the degreasing solution. By immersing the metal material in the degreasing solution at ℃ for 20 to 30 seconds to remove the oil component present on the surface of the metal material primarily.

의 전류밀도로 약 5 ~ 10분동안 탈지하게 된다.Next, the electrolytic degreasing step (S14) is a metal material that is primarily degreased in the immersion degreasing step into the electrolyte of about 60 ℃ of PH 9 ~ 11 1

Degreasing for about 5 to 10 minutes at the current density of.

At this time, the degreasing and electrolytic degreasing step (S12) and the electrolytic degreasing step (S14) can be performed continuously by using the same degreasing solution and electrolyte solution (for example, manufacturer: Sangil Chemtech's liquid degreasing agent RTO-CLEANER). Of course you can.

Next, the first hot water washing step (S20) serves to remove foreign matters remaining on the surface of the metal material, in particular, an organic film such as a surfactant, by washing the metal material in which the degreasing operation is completed in a hot water of about 60 ° C. To do.

In this case, in the first hot water washing step (S20), three steps of washing with water, that is, three washing processes, may be used to more completely remove the organic film remaining on the surface of the metal material.

Next, the acid treatment step (S30) relates to the step of removing foreign substances such as rust or residual oil in the metal material after washing with hot water, using hydrochloric acid at about 30-40 ° C. which is 20% by percent concentration. Acid treatment for about 1 to 3 minutes.

Next, after the acid treatment step (S30) is a water washing step for removing the foreign matter present on the surface of the metal material, it is subjected to washing three times using water at room temperature, that is, about 20 ~ 30 ℃.

At this time, the washing step is made repeatedly after each step of the process of the plating method using the tin-zinc alloy plating solution according to the present invention, will be omitted after the detailed description.

On the other hand, the plating method using a tin-zinc alloy plating solution according to the present invention may further comprise a chemical polishing step (S40) after the acid treatment step (S30), the chemical polishing step (S40) is a strong acid, By immersing the metal material in a solution such as strong alkali, the component which is difficult to react with acid becomes fine powder, and serves to remove smut remaining on the surface of the metal material. In the present invention, it is about 30 to 40 ° C. Chemical polishing is performed for 30 to 60 seconds using KCRUKA #MP solution (manufacturer: Sangil Chemtech's chemical polishing agent) having a concentration of 50%.

In addition, the plating method using a tin-zinc alloy plating solution according to the present invention may be configured to further include a neutralization treatment step (S50) after the washing step after the chemical polishing step (S40), the neutralization step (S50) is described later by completely removing the acid groups remaining on the surface of the acid-treated and chemically polished metal material and matching the surface PH of the metal material with the PH (5.8 ~ 6.2) of the tin-zinc alloy plating solution according to the present invention described above. In the tin-zinc plating step (S70), uniform plating may be performed on the surface of the metal material, and the adhesion of the plating layer may be strengthened to improve corrosion resistance.

In the neutralization step (S50), 10 to 20 in an aqueous solution in which 50 g / L of TOP-F (manufacturer: JP Chemical) and 15 g / L of NaCN (sodium cyanide) are mixed with the chemically ground metal material at a temperature of 30 to 40 ° C. Immersion for seconds allows the surface PH of the metal material to match the PH (5.8-6.2) of the tin-zinc alloy plating solution.

Next, the first activation step (S60) is to activate the surface of the metal material after the acid treatment step (S30) or neutralization step (S50) of the tin-zinc plating solution in the tin-zinc plating step (S70) to be described later It is to serve to improve the adhesion, it is made for about 3 seconds at a temperature of 30 ~ 40 ℃.

의 전류밀도를 가하여 10 ~ 30 rpm으로 회전시키면서 약 60분 동안 도금작업이 진행된다.Next, the tin-zinc plating step (S70) relates to the step of plating the surface of the metal material by immersing the metal material completed activation in the first activation step (S60) in the tin-zinc plating solution according to the present invention. , Immersed in a tin-zinc plating solution (plating bath) of 30 to 40 ℃ having a specific gravity of 11 to 13, voltage of 2.0 to 2.5V and 1.5

The plating process is performed for about 60 minutes while rotating at 10 to 30 rpm with the current density of.

After the tin-zinc plating step (S70) as described above, after washing with water, a second activation step (S80) is performed, and the second activation step (S80) is performed before chromatizing the metal material on which plating is completed. To act to activate the anti-rust coating on the surface of the metal material.

At this time, in the second activation step (S80), the surface of the metal material is activated by dipping the metal material on which the plating is completed in a citric acid solution (50 g / L) at a temperature of 30 to 40 ° C. for about 3 seconds.

Next, after the second activation step (S80), after washing with water again, a chromate (Sromate) step (S90) of coating a rust preventive coating on the surface of the activated metal material, the chromate step (S90) is plated By forming an antirust film (coating layer) mainly composed of chromic acid on the surface of the completed metal material, it serves to improve the corrosion resistance and wear resistance of the plated metal material and at the same time improve the glossiness.

At this time, the chromate step (S90) is a metal material of which the plating is completed, the temperature is 20 ~ 30 ℃, 10 ~ 20% concentration mainly composed of chromic acid or dichromic acid, for about 30 ~ 90 seconds in a solution of PH 3.0 ~ 4.0 By dipping.

In addition, in the chromate step (S90), by using a colored, yellow or black chromate selectively depending on the purpose of the metal material to be plated, the rust-proof coating layer can be configured to have a white, yellow or black.

Next, the plating method using a tin-zinc alloy plating solution according to the present invention is a room temperature standing step of leaving the metal material taken out of the solution containing chromic acid or dichromic acid after the chromate step (S90) at room temperature for 20 to 40 seconds ( It may be configured to further include S100, the room temperature leaving step (S100) is to give a time to allow the chromate coating, that is, the rustproof coating evenly formed on the surface of the metal material.

In other words, when the water washing operation is performed immediately after the chromate treatment as in the prior art, the formation of the coating layer becomes unstable and the corrosion resistance is deteriorated, whereas in the present invention, the chromate treated metal material at room temperature for 20 to 40 seconds. By leaving water running after leaving the coating layer is given time to improve the overall corrosion resistance.

On the other hand, as described above, the metal material having the antirust film formed on the surface undergoes a water washing operation and then undergoes a second hot water washing step (S110), wherein the second hot water washing step (S110) is a metal material having completed the antirust treatment and washing operation. By immersing in a hot water of 50 ~ 70 ℃ for 5 to 15 minutes to more completely remove the foreign matter remaining on the surface of the metal material, that is, the organic film remaining on the surface after plating.

Next, the metal material subjected to the second hot water washing step as described above is subjected to a drying step (S120) of drying for about 15 to 25 minutes at a temperature of 40 ~ 60 ℃ by plating using a tin-zinc alloy plating solution according to the present invention. The process is complete.

Table 11 below shows the salt spray test data of the plated product manufactured by the plating method using the tin-zinc alloy plating solution according to the present invention, and the corrosion resistance of the conventional tin plating is much improved compared to that of 96 hours. You can see the result.

In addition, it can be seen that an additional corrosion resistance improvement effect of about 2 times can be obtained during chromate treatment.

Therefore, according to the plating method using the tin-zinc alloy plating solution according to the present invention as described above, nicotinic acid and cocamidopropyl betaine in an electrolyte consisting of tin and zinc during the surface treatment of rust-preventing materials generally used in automobiles and constructions, etc. Addition of ethylenediaminetetraacetic acid-4sodium salt and glycerin is added to suppress the variation of low-current site plating layer, and to suppress the increase of current value. As it can be secured, it is possible to improve workability and weldability, and plating on materials which are susceptible to acid or alkali, such as ceramic composite parts, and the coating layer of the plating layer has corrosion resistance against salt spray and sulfurous acid gas. Neutralizer not used in conventional plating process It is to have a variety of advantages, such as to further improve the corrosion resistance of the plated layer by further applying a process such as li, room temperature standing, hot water washing.

Although the preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention.

The present invention relates to a plating method using a tin-zinc alloy plating solution, and more specifically, nicotinic acid and cocamidopropyl betaine are added to an electrolyte solution consisting of tin and zinc during surface treatment of rust-preventing materials commonly used in automobiles and constructions. In order to suppress the variation of the low current site plating layer, and in particular, to add a positive electrode sludge and to suppress the increase of the current value, the ethylenediaminetetraacetic acid-4 sodium salt and glycerin are added to secure a uniform plating layer of the low current site. The present invention relates to a plating method using a tin-zinc alloy plating solution.

S10: degreasing step S12: immersion degreasing step
S14: electrolytic degreasing step S20: first hot water washing step
S30: acid treatment step S40: chemical polishing step
S50: neutralization step S60: first activation step
S70: tin-zinc plating step S80: second activation step
S90: chromate step S100: room temperature step
S110: second hot water washing step S120: drying step

Claims (5)

In the plating method using a tin-zinc alloy plating solution,
A degreasing step for degreasing the surface of the metal material to be plated;
A first hot water washing step of washing the dehydrated metal material in a hot water at 60 ° C.,
An acid treatment step of acid treatment of the metallic material after washing with hot water using hydrochloric acid having a concentration of 20%,
A chemical polishing step of polishing the surface of the metal material after the acid treatment step;
A first activation step of activating a metal material after acid treatment,
A tin-zinc plating step of plating an activated metal material using a tin-zinc alloy plating solution;
A second activation step of activating the metal material after the plating operation,
A chromate step of coating an antirust film on the surface of the activated metal material;
Plating method using a tin-zinc alloy plating solution, characterized in that it comprises a second hot water washing step of washing the rust-prevented metal material in a hot water of 50 ~ 70 ℃.
delete The method of claim 1,
After the chemical polishing step, further comprising a neutralization step of neutralizing the chemically polished metal material plating method using a tin-zinc alloy plating solution.
The method of claim 1,
After the chromate step, a plating method using a tin-zinc alloy plating solution, characterized in that it further comprises a room temperature leaving step of leaving the rust-treated metal material at room temperature for 20 to 40 seconds.
The method of claim 1,
The degreasing step,
An immersion degreasing step of degreasing the surface of the metal material by immersing the metal material in the degreasing solution;
A plating method using a tin-zinc alloy plating solution, comprising an electrolytic degreasing step of immersing a first degreased metal material in an electrolytic solution and secondly degreasing the surface of the metal material.

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