KR102656417B1 - High corrosion resistance surface treatment method of liftgate hinge made of aluminum alloy material - Google Patents

Abstract

The present invention relates to a highly corrosion-resistant surface treatment method for a liftgate hinge made of aluminum alloy material, and more specifically, a degreasing step, an etching step, a dismut step, a zincate step, a zinc plating step, a zinc nickel alloy plating step, and a chromate step. It relates to a highly corrosion-resistant surface treatment method for a liftgate hinge made of an aluminum alloy material, characterized in that it includes a treatment step. The highly corrosion-resistant surface treatment method according to an embodiment of the present invention is applied to a liftgate hinge made of an aluminum alloy material. By applying the zinc and zinc nickel alloy plating process, the problem of peeling off the paint layer due to the oxide film (Al ₂ O ₃ ), which is a characteristic of aluminum alloy material, can be prevented when applying the painting process after manufacturing the liftgate hinge product. It relates to a highly corrosion-resistant surface treatment method for a liftgate hinge made of aluminum alloy material, which has the advantage of reducing the defect formation rate by having corrosion resistance equivalent to that of steel alloy material.

Description

High corrosion resistance surface treatment method for liftgate hinge made of aluminum alloy material {HIGH CORROSION RESISTANCE SURFACE TREATMENT METHOD OF LIFTGATE HINGE MADE OF ALUMINUM ALLOY MATERIAL}

The present invention relates to a highly corrosion-resistant surface treatment method for a liftgate hinge made of aluminum alloy material, and more specifically, a degreasing step, an etching step, a dismut step, a zincate step, a zinc plating step, a zinc nickel alloy plating step, and a chromate step. It relates to a highly corrosion-resistant surface treatment method for a liftgate hinge made of aluminum alloy material, which includes a treatment step.

Recently, as the electric vehicle industry has developed, interest in related parts and advanced technologies is increasing, and interest in technological advancements such as lightweighting of automobile parts is also increasing. In other words, in the case of automobile parts, there is a trend of changing from existing steel alloy materials to aluminum alloy materials for weight reduction.

Republic of Korea Patent No. 10-2297507 discloses technology related to an ultra-light aluminum alloy brake caliper casting device for electric vehicles, and Republic of Korea Patent No. 10-1812493 discloses an aluminum coil assembly with a galvanic corrosion prevention structure for an electronic clutch for automobiles. The related technology is disclosed, and Republic of Korea Patent No. 10-1191772 discloses the technology related to the manufacturing method of the aluminum alloy composition for automobile steering wheel.

Liftgate hinge is a part that fixes car trunk parts and is involved in automatic force, opening and closing force, rigidity, and noise. It can be said to be a functional safety part that contributes to minimizing damage to the vehicle and passengers in the event of a collision.

Among automobile components, technology development is underway to replace liftgate hinges from steel alloy materials to aluminum alloy materials, but surface treatment technology for liftgate hinges made of aluminum alloy materials has not been secured, and related technology development is also underway. The situation is insufficient.

In order to reduce the weight of automobile parts such as liftgate hinges, development is needed to change from existing steel alloy materials to aluminum alloy materials. However, when painting after manufacturing a liftgate hinge product made of aluminum alloy materials, an oxide film (Al ₂ O ₃ ) may cause the problem of the paint layer peeling off, so a solution to this problem is needed. In other words, there is a need to develop surface treatment technology for liftgate hinges made of aluminum alloy materials.

Therefore, in the present invention, by applying the zinc and zinc-nickel alloy plating process to the liftgate hinge made of aluminum alloy material, the oxide film (Al ₂ O ₃ ), which is a characteristic of the aluminum alloy material, is applied to the painting process after manufacturing the liftgate hinge product. A highly corrosion-resistant surface treatment method was developed to prevent the problem of peeling off the paint layer and to have corrosion resistance equivalent to that of steel alloy materials.

Republic of Korea Patent No. 10-2297507 (registered on August 27, 2021) Republic of Korea Patent No. 10-1812493 (registered on December 20, 2017) Republic of Korea Patent No. 10-1191772 (registered on October 10, 2012)

The present invention was created to solve the problems described above and provide the necessary technology,

The present invention provides a highly corrosion-resistant surface treatment of a liftgate hinge made of aluminum alloy material, comprising a degreasing step, an etching step, a dismut step, a zincate step, a zinc plating step, a zinc nickel alloy plating step, and a chromate treatment step. The purpose is to provide a method.

In addition, the present invention applies a zinc and zinc-nickel alloy plating process to a liftgate hinge made of an aluminum alloy material, so that the oxide film (Al ₂ O ₃ ), which is a characteristic of the aluminum alloy material, is applied to the painting process after manufacturing the liftgate hinge product. This prevents problems with the paint layer peeling off, and has corrosion resistance equivalent to that of steel alloy materials, which has the advantage of reducing the rate of defect formation. Highly corrosion-resistant surface treatment of the liftgate hinge made of aluminum alloy material. There is another purpose in providing a method.

As an embodiment of the present invention to achieve the above object,

One embodiment of the present invention is a method of surface treatment of a liftgate hinge made of an aluminum alloy material, wherein the liftgate hinge made of an aluminum alloy material to be plated is soaked in a degreasing solution maintained at a temperature of 40 to 50° C. for 10 to 15 minutes. A degreasing step of supporting and degreasing; An etching step of etching the plated body degreased in the degreasing step by immersing it in an etching solution maintained at a temperature of 40 to 50° C. for 3 to 10 minutes; A desmut step of removing smut by immersing the plated body etched in the etching step in a dismut solution maintained at a temperature of 20 to 30° C. for 2 to 4 minutes; A zincate step of substituting and precipitating zinc by immersing the plated body from which smut has been removed in the dismut step in a zincate solution maintained at a temperature of 20 to 30° C. for 50 to 90 seconds; A zinc plating step of electroplating the plated body from which zinc has been deposited in the zincate step using a zinc plating solution at a temperature of 20 to 30° C. for 8 to 12 minutes at a current intensity of 1 to 2 A; A zinc nickel alloy plating step of electroplating the plated body zinc plated in the zinc plating step using a zinc nickel alloy plating solution at a temperature of 18 to 25° C. for 15 to 25 minutes at a current intensity of 1 to 2 A; And in the zinc nickel alloy plating step, the zinc nickel alloy plated body is immersed in a chromate solution with a pH of 1.6 to 2.0 and a temperature maintained at 50 to 60°C for 30 to 90 seconds to form a chromate film on the surface of the plated body. A chromate treatment step; wherein the degreasing liquid in the degreasing step contains 2 to 3 g/L of sodium metasilicate nonahydrate 9Hydrate and 23 g/L of sodium carbonate based on 1 L of the total degreasing liquid. to 27 g/L and 1 to 3 g/L of disodium ethylene diamine tetra acetic acid (EDTA-2Na), and the etching solution in the etching step is based on 1 L of the entire etching solution. It is characterized in that it contains 10 to 20 g/L of sodium hydroxide, and the dismut liquid in the dismut stage contains 300 to 400 mL/L of nitric acid based on 1 L of the total dismut liquid. Characterized in that, the zincate solution in the zincate stage contains 10 to 20 g/L of iron chloride, 80 to 100 g/L of nickel sulfate, and sodium hydroxide ( It is characterized in that it contains 70 to 100 g/L of sodium hydroxide and 100 to 120 g/L of zinc oxide, and the zinc plating solution in the zinc plating step contains sodium hydroxide (Sodium) based on the entire 1L of the zinc plating solution. hydroxide) 120 to 140 g/L, zinc oxide (Zinc oxide) 10 to 14 g/L, N,N'-bis[3-(dimethylamino)propyl] and 1,1'-oxybis[2-chloroethane] polymer Characterized in that it includes 7 to 10 mL/L of the combination and 1 to 3 mL/L of the pyridinium mixture, wherein the pyridinium mixture is 1-benzyl-pyridinium-3-carboxylate (3-carboxy-1-(phenylmethyl ) Pyridinium) (1-Benzyl-pyridinium-3-carboxylate(3-Carboxy-1-(phenylmethyl)pyridinium)), Chloride and Sodium salt are mixed in a ratio of 1:1:1. The zinc nickel alloy plating solution in the zinc nickel alloy plating step contains 120 to 140 g/L of sodium hydroxide and 10 g/L of zinc oxide based on the total 1 L of the zinc nickel alloy plating solution. to 14 g/L, tetraethylenepentamine (Tetraethylenepentamine) 20 to 30 mL/L, nickel sulfate (Nickel sulfate) 6 to 8 g/L, and pyridinium mixture 1 to 3 mL/L, wherein the pyridinium mixture is 1-Benzyl-pyridinium-3-carboxylate(3-Carboxy-1-(phenylmethyl)pyridinium), chloride It is characterized in that it is composed of chloride and sodium salt mixed in a ratio of 1:1:1, and the chromate solution in the chromate treatment step contains sodium hydroxide based on the total 1L of the chromate solution. 8 to 12 g/L, Nitric acid 25 to 35 mL/L, Chromium nitrate 400 to 500 g/L, Chromium chloride 100 to 120 g/L, and Oxalic acid 80 to 120 g/L. Provided is a highly corrosion-resistant surface treatment method for a liftgate hinge made of aluminum alloy material, characterized in that L is included.

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The highly corrosion-resistant surface treatment method for a liftgate hinge made of an aluminum alloy material according to an embodiment of the present invention involves applying a zinc and zinc-nickel alloy plating process to a liftgate hinge made of an aluminum alloy material, followed by a painting process after manufacturing the liftgate hinge product. When applying, it is possible to prevent the problem of the coating layer peeling off due to the oxide film (Al ₂ O ₃ ), which is a characteristic of aluminum alloy material, and can have corrosion resistance equivalent to that of steel alloy material, thereby reducing the defect formation rate. There are advantages to this.

Figure 1 is a flowchart showing the high corrosion resistance surface treatment method of a liftgate hinge made of an aluminum alloy material in each process step according to an embodiment of the present invention.
Figure 2 is a photograph observing the appearance of a liftgate hinge made of an aluminum alloy material that has been surface treated with high corrosion resistance by a method according to an embodiment of the present invention.
Figure 3 is a photograph observing the surface treatment results of a liftgate hinge made of aluminum alloy material according to the process time of the degreasing step (S ₁₀₀ ).
Figure 4 is a photograph observing the surface treatment results of a liftgate hinge made of aluminum alloy material according to the process time of the etching step (S ₂₀₀ ).
Figure 5 is a photograph observing the surface treatment results of a liftgate hinge made of aluminum alloy material according to the process time of the desmut step (S ₃₀₀ ).

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

Throughout the specification of the present invention, when a part “includes” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

Throughout the specification of the present invention, when a step is said to be located “on” or “before” another step, this means not only when a step is in a direct time-series relationship with another step, but also when a step is in a direct time-series relationship with the other step, as well as a mixing step after each step. Likewise, the order of two steps can include the same rights as in the case of an indirect time-series relationship in which the time-series order can be changed.

The terms "about", "substantially", etc. used throughout the specification of the present invention are used to mean at or close to that value when manufacturing and material tolerances inherent in the stated meaning are presented, and the present invention Precise or absolute figures are used to aid understanding and to prevent unscrupulous infringers from taking unfair advantage of the disclosure. The term “step of” or “step of” used throughout the specification does not mean “step for.”

The terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

The present invention relates to a highly corrosion-resistant surface treatment method for a liftgate hinge made of aluminum alloy material, and more specifically, to a degreasing step (S ₁₀₀ ), an etching step (S ₂₀₀ ), a dismut step (S ₃₀₀ ), and a zincate step. (S ₄₀₀ ), zinc plating step (S ₅₀₀ ), zinc nickel alloy plating step (S ₆₀₀ ), and chromate treatment step (S ₇₀₀ ).

Hereinafter, a highly corrosion-resistant surface treatment method (hereinafter also referred to as ‘surface treatment method’) of a liftgate hinge made of an aluminum alloy material according to an embodiment of the present invention will be described in detail. The method of treating the highly corrosion-resistant surface of a liftgate hinge made of an aluminum alloy material according to an embodiment of the present invention can be more clearly understood through the description below.

Figure 1 is a flowchart showing the high corrosion resistance surface treatment method of a liftgate hinge made of an aluminum alloy material in each process step according to an embodiment of the present invention.

First, a degreasing step (S ₁₀₀ ) can be performed.

A degreasing step (S ₁₀₀ ) is performed in which the liftgate hinge made of aluminum alloy material, which is the body to be plated, is degreased by immersing it in a degreasing liquid.

Degreasing is a process performed to remove oily contaminants. In plating, degreasing cleaning, including cleaning, includes alkaline degreasing (cleaning), solvent degreasing (cleaning), and electrolytic degreasing (cleaning).

The degreasing step (S ₁₀₀ ) of the present invention is a process performed to remove contaminants from the metal surface generated depending on the material, shape, manufacturing process, and manufacturing environment of the object to be plated, and can be considered a general plating preparation operation. Degreasing can be said to be an important process in the plating process, and if degreasing is insufficient, it can cause defects such as poor adhesion, poor gloss, rough plating, and swelling.

According to one embodiment of the present invention, the degreasing step (S ₁₀₀ ) is characterized in that the liftgate hinge is degreased by immersing it in a degreasing solution maintained at a temperature of 40 to 50° C. for 10 to 15 minutes.

In the degreasing step (S ₁₀₀ ), it is preferable to degrease the liftgate hinge made of aluminum alloy material by immersing it in a degreasing solution maintained at a temperature of 40 to 50°C. This means that when degreasing at a temperature below 40°C, the degreasing time This is because there is a risk that non-degreasing may occur as the temperature increases, and if degreasing is performed at a temperature exceeding 50°C, there is a risk that the lifespan of the degreasing solution may be shortened.

In addition, in the degreasing step (S ₁₀₀ ), it is preferable to degrease the liftgate hinge made of an aluminum alloy material by immersing it in a degreasing liquid for 10 to 15 minutes. This means that when degreasing for less than 10 minutes, the liftgate hinge is partially undegreased. This is because there is concern that this may occur, and if degreasing is performed for a time exceeding 15 minutes, additional unnecessary time is spent after complete degreasing and there is concern that productivity may be reduced.

According to one embodiment of the present invention, the degreasing solution in the degreasing step (S ₁₀₀ ) is sodium metasilicate nonahydrate 9Hydrate (Na ₂ O·SiO ₂ ·9H ₂ O) 2 based on the total 1L of degreasing fluid. to 3 g/L, sodium carbonate (Na ₂ CO ₃ ) 23 to 27 g/L, and disodium ethylenediaminetetraacetic acid (EDTA-2Na, Ethylene diamine tetra acetic acid-disodium) 1 to 3 g/L. Do it as

Due to the nature of aluminum, if sodium hydroxide (NaOH) or potassium hydroxide (KOH) is added to the degreasing solution during the degreasing process, the degreasing solution becomes basic and may react with the aluminum material and cause corrosion as it is etched. there is.

Accordingly, the degreasing liquid used in the degreasing step (S ₁₀₀ ) is preferably a solution with a neutral pH, and the degreasing liquid contains sodium metasilicate nonahydrate 9Hydrate, Na ₂ O·SiO ₂ 9H ₂ O ), sodium carbonate (Na ₂ CO ₃ ), and disodium ethylenediaminetetraacetic acid (EDTA-2Na, Ethylene diamine tetra acetic acid-disodium).

Next, an etching step (S ₂₀₀ ) can be performed.

An etching step (S ₂₀₀ ) is performed in which the plated body degreased in the degreasing step (S ₁₀₀ ) is etched by immersing it in an etching solution.

The etching process refers to a method of chemically or electrochemically corroding a metal or non-metal surface.

The etching step (S ₂₀₀ ) of the present invention is a process performed to improve plating adhesion by etching the plated body with a liquid containing an oxidizing agent to cause surface roughening and chemical changes, that is, the surface of the material in the pre-treatment of plating on the resin. This is a process performed to provide plating adhesion by finely activating (carving) the plating.

According to one embodiment of the present invention, the etching step (S ₂₀₀ ) is characterized in that the plated body is etched by immersing it in an etching solution maintained at a temperature of 40 to 50° C. for 3 to 10 minutes.

In the etching step (S ₂₀₀ ), it is preferable to immerse the plated body in an etching solution maintained at a temperature of 40 to 50° C. for 3 to 10 minutes to etch, which is etched at a temperature exceeding 50° C. or etching for more than 10 minutes. If etching is performed for a period of time, there is a risk that excessive etching may cause poor plating adhesion to the surface of the plated object. Even if etched for less than 3 minutes, the etching may proceed insufficiently and cause poor plating adhesion. Because there are concerns.

According to one embodiment of the present invention, the etching solution of the etching step (S ₂₀₀ ) is characterized in that it contains 10 to 20 g/L of sodium hydroxide (NaOH) based on the entire 1 L of the etching solution.

Next, a dismut step (S ₃₀₀ ) can be performed.

A desmut step (S ₃₀₀ ) is performed in which the plated body etched in the etching step (S ₂₀₀ ) is immersed in a desmut solution to remove smut.

The dismut process is a process performed to separate and remove smut, a trace component (Si, Co, Fe, etc.), from the surface of the alloy material after etching.

After etching, smut components, which appear black, are attached to the surface of the alloy material. Although the smut component adheres to the surface of the alloy material, it does not have strong adhesion, and is usually in the form of hydrate (nH ₂ O), and adheres to the surface of the material like a fine powder. To prevent lifting during plating and to prevent plating defects, smut must be removed in advance. In particular, smut must be removed in the plating or anodizing process as it can have a decisive effect. To remove smut components, oxidizing agents such as nitric acid (HNO ₃ ) and sulfuric acid (H ₂ SO ₄ ) are mainly used.

According to one embodiment of the present invention, in the desmut step (S ₃₀₀ ), the smut is removed by immersing the plated body in a desmut liquid maintained at a temperature of 20 to 30 ° C. for 2 to 4 minutes. do.

In the dismut step (S ₃₀₀ ), it is preferable to remove smut by immersing the object to be plated in the dismut solution for 2 to 4 minutes. However, if immersion is performed for less than 2 minutes, smut removal does not proceed completely. This is because there is a risk of poor plating adhesion occurring during the subsequent plating process, and if immersion is performed for a time exceeding 4 minutes, additional unnecessary time is spent after smut removal is completely completed, which may reduce productivity. am.

According to one embodiment of the present invention, the dismut liquid in the dismut step is characterized in that it contains 300 to 400 mL/L of nitric acid (HNO ₃ ) based on 1 L of the total dismut liquid.

Next, the zincate step ( _S400 ) can be performed.

A zincate step (S ₄₀₀ ) in which the plated body from which the smut has been removed in the dismut step (S ₃₀₀ ) is immersed in a zincate solution maintained at a temperature of 20 to 30 ° C. for 50 to 90 seconds to replace zinc and precipitate it. ) is performed.

Zinccate is a plating method that uses the potential difference between different metals. It belongs to electroless plating and refers to a method of substituting zinc and precipitating it by immersing it in a zincate solution.

The natural oxide film on the aluminum alloy material disappears as a substitution reaction between zinc particles and aluminum particles occurs, and the zinc particles cover the surface. As the substituted zinc particle forming layer does not create a dense oxide film, adhesive plating is possible with subsequent plating. do. That is, the zincating step (S ₄₀₀ ) of the present invention is performed as a pretreatment process to increase plating adhesion.

In the zincate step (S ₄₀₀ ), it is preferable to immerse the plated body from which the smut has been removed in the zincate solution for 50 to 90 seconds. This means that when immersed for less than 50 seconds, the film layer is not properly coated. There is a risk that problems may occur, and if immersion is performed for a time exceeding 90 seconds, unnecessary time is spent after the film layer is completely coated, which may reduce productivity.

According to one embodiment of the present invention, the zincate solution in the zincate step contains 10 to 20 g/L of iron chloride (FeCl ₂ ) and 80 g/L of nickel sulfate (NiSO ₄ ) based on the entire 1L of zincate solution. to 100 g/L, 70 to 100 g/L of sodium hydroxide (NaOH), and 100 to 120 g/L of zinc oxide (ZnO).

Next, the galvanizing step (S ₅₀₀ ) can be performed.

A zinc plating step (S) in which the plated body from which zinc is precipitated in the zincate step (S ₄₀₀ ) is electroplated using a zinc plating solution at a current intensity of 1 to 2 A for 8 to 12 minutes at a temperature of 20 to 30 ° C. ₅₀₀ ).

The zinc plating step (S ₅₀₀ ) of the present invention involves plating zinc on the zincate coating surface for adhesion prior to zinc nickel alloy plating, a process performed to increase plating adhesion of zinc nickel alloy plating of aluminum alloy material. It can be said that In other words, in the zinc plating step (S ₅₀₀ ) of the present invention, direct plating of zinc nickel alloy on aluminum alloy material may be difficult and poor plating adhesion may occur, so zinc plating, which is relatively excellent in direct adhesion on aluminum alloy material, is used. It can be said to be a process performed to perform plating first.

Although not limited to this, the zinc plating step (S ₅₀₀ ) uses an anode zinc at least twice the area of the object to be plated as an anode, covers the anode bag to prevent sludge from being generated at the anode, and then adds it to the zinc plating solution. After immersion, it is desirable to proceed with plating by agitating the air while applying an electric current.

In the zinc plating step (S ₅₀₀ ), it is preferable to electroplate the object to be plated by applying a current at a temperature of 20 to 30°C using a zinc plating solution. In the case of electroplating at a temperature below 20°C, the plating is This is because there is a risk that it may become brittle and cause adhesion failure, and if electroplating is performed at a temperature exceeding 30°C, there is a risk that the plating surface may become rough.

In addition, in the zinc plating step (S ₅₀₀ ), it is preferable to electroplate the object to be plated by applying a current for 8 to 12 minutes using a zinc plating solution. This means that when electroplating is performed for less than 8 minutes, zinc plating is performed. This is because there is a risk that plating may become thin because this does not proceed sufficiently, resulting in non-plating occurring in the zinc nickel alloy plating bath during the zinc nickel alloy plating process later.

In addition, in the zinc plating step (S ₅₀₀ ), it is preferable to electroplate the body to be plated at a current intensity of 1 to 2A using a zinc plating solution. This means that when electroplating at a current intensity exceeding 2A, the plated body This is because there is a risk that the contact surface that the jig touches may burn.

According to one embodiment of the present invention, the zinc plating solution in the zinc plating step (S ₅₀₀ ) contains 120 to 140 g/L of sodium hydroxide (NaOH) and zinc oxide (Zinc oxide) based on 1 L of the entire zinc plating solution. ZnO) 10 to 14 g/L, a combination of N,N'-bis[3-(dimethylamino)propyl] and 1,1'-oxybis[2-chloroethane] polymer (N,N'-bis[3 -(dimethylamino)propyl], polymer with 1,1'-oxybis[2-chloroethane]) and 7 to 10 mL/L and 1 to 3 mL/L of pyridinium mixture.

At this time, the pyridinium mixture is 1-benzyl-pyridinium-3-carboxylate (3-carboxy-1- (phenylmethyl) pyridinium) (1-Benzyl-pyridinium-3-carboxylate (3-Carboxy-1- ( It is characterized in that it is composed of phenylmethyl)pyridinium), chloride, and sodium salt mixed in a ratio of 1:1:1.

Although not limited thereto, the zinc plating layer formed in the zinc plating step (S ₅₀₀ ) is preferably formed to a thickness of 3 to 7㎛, which means that if the zinc plating layer is formed to a thickness of less than 3㎛, the plating is too thin. This is because there is a risk that non-plating may occur in the zinc nickel alloy plating bath during the zinc nickel alloy plating process in the future, and if the zinc plating layer is formed with a thickness exceeding 7㎛, there is a risk that it may become a factor in poor plating adhesion. Because there is.

Next, the zinc nickel alloy plating step (S ₆₀₀ ) can be performed.

A zinc nickel alloy plating step of electroplating the zinc plated body in the zinc plating step (S ₅₀₀ ) using a zinc nickel alloy plating solution at a temperature of 18 to 25°C for 15 to 25 minutes with a current intensity of 1 to 2 A. Perform (S ₆₀₀ ).

The zinc-nickel alloy plating process is a zinc alloy plating containing 5 to 10% nickel (volume or weight ratio), which involves an acid bath and an alkaline bath. Compared to zinc plating, hydrogen embrittlement is less, and processability such as weldability is good. It has the advantage of excellent heat corrosion resistance.

The zinc nickel alloy plating step (S ₆₀₀ ) of the present invention applies the zinc nickel alloy plating process to a liftgate hinge made of an aluminum alloy material, thereby applying the painting process after manufacturing the liftgate hinge product to remove the oxide film, which is a characteristic of the aluminum alloy material. It can be said to be a process performed to prevent problems with the paint layer peeling off due to (Al ₂ O ₃ ) and to have corrosion resistance equivalent to that of steel alloy materials.

Although not limited to this, the zinc nickel alloy plating step (S ₆₀₀ ) uses an anode nickel at least twice the area of the plated body as an anode, covers the anode bag to prevent sludge from being generated at the anode, and then zinc nickel. It is preferable to proceed with plating by immersing the alloy plating solution and agitating it with air while applying an electric current.

In the zinc nickel alloy plating step (S ₆₀₀ ), it is preferable to electroplate the plated body using a zinc nickel alloy plating solution by applying a current at a temperature of 18 to 25°C. This is when electroplating is performed at a temperature of less than 18°C. This is because there is a risk that plating becomes fragile and poor adhesion may occur, and in the case of electroplating at a temperature exceeding 25°C, there is a risk that the plating surface may become rough or the polish may decompose, causing problems such as increased consumption of polish. am.

In addition, in the zinc nickel alloy plating step (S ₆₀₀ ), it is preferable to electroplate the plated body using a zinc nickel alloy plating solution by applying electric current for 15 to 25 minutes, which is when electroplating is performed for less than 15 minutes. There is a risk that the zinc-nickel alloy plating may not proceed sufficiently, resulting in reduced corrosion resistance or lack of gloss or reduced glossiness, and if electroplating is performed for a time exceeding 25 minutes, there is a risk of poor plating adhesion.

In addition, in the zinc-nickel alloy plating step (S ₆₀₀ ), it is preferable to electroplate the plated body using a zinc alloy plating solution at a current intensity of 1 to 2A. This means that in the case of electroplating at a current intensity exceeding 2A, This is because there is a risk of burning the contact surface between the plated body and the jig.

According to one embodiment of the present invention, the zinc nickel alloy plating solution in the zinc nickel alloy plating step (S ₆₀₀ ) contains 120 to 140 g/L of sodium hydroxide (NaOH) based on the entire 1 L of the zinc nickel alloy plating solution, Zinc oxide (ZnO) 10 to 14 g/L, tetraethylenepentamine (C ₈ H ₂₃ N ₅ ) 20 to 30 mL/L, nickel sulfate (NiSO ₄ ) 6 to 8 g/L, and fluorine It is characterized in that 1 to 3 mL/L of dinium mixture is included.

At this time, the pyridinium mixture is 1-benzyl-pyridinium-3-carboxylate (3-carboxy-1- (phenylmethyl) pyridinium) (1-Benzyl-pyridinium-3-carboxylate (3-Carboxy-1- ( It is characterized in that it is composed of phenylmethyl)pyridinium), chloride, and sodium salt mixed in a ratio of 1:1:1.

Next, a chromate treatment step (S ₇₀₀ ) can be performed.

In the zinc nickel alloy plating step (S ₆₀₀ ), the zinc nickel alloy plated body is immersed in a chromate solution with a pH of 1.6 to 2.0 and a temperature of 50 to 60°C for 30 to 90 seconds to form a chromate film on the surface of the plated body. A chromate treatment step (S ₇₀₀ ) to form is performed.

Chromate treatment can be said to be a method of creating a rust-prevention film by immersing a plated body in a solution containing chromic acid or dichromate as the main ingredient.

That is, chromate treatment means immersing a plated body plated with zinc or the like in a chromate solution containing chromic acid to form a chromate film (rust-prevention film) on the surface of the plated body. Chromate treatment has the advantage of improving the corrosion resistance of the plated body, preventing the occurrence of white rust, improving the appearance by making it difficult for fingerprints and other contaminants to attach, and improving the adhesion of paints and dyes. It works.

In the chromate treatment step (S ₇₀₀ ), it is preferable to form a chromate film on the surface of the plated body by immersing the plated body in a chromate solution maintained at 50 to 60°C for 30 to 90 seconds, which is 30°C at a temperature below 50°C. This is because if immersed for less than a second, there is a risk that blue chromate may appear or the chromate treatment may not proceed properly, causing a problem in which the chromate film is not properly formed. If the immersion time exceeds 90 seconds at a temperature exceeding 60°C, This is because, in the case of immersion during the chromate treatment process, problems such as burning of the plated material or staining of the color may occur.

In addition, in the chromate treatment step (S ₇₀₀ ), it is preferable to form a chromate film on the surface of the plated body by immersing the plated body in a chromate solution with a pH of 1.6 to 2.0. This is because the color varies depending on pH, and when the pH is less than 1.6, the chromate film is preferably formed on the surface of the plated body. In this case, a problem may occur where the plated body is burned during the chromate treatment process.

According to one embodiment of the present invention, the chromate solution in the chromate treatment step contains 8 to 12 g/L of sodium hydroxide (NaOH) and 25 to 35 mL/L of nitric acid (HNO ₃ ) based on the entire 1 L of the chromate solution. L, Chromium nitrate (Cr(NO ₃ ) ₂ ) 400 to 500 g/L, Chromium chloride (CrCl ₂ ) 100 to 120 g/L, and Oxalic acid (H ₂ C ₂ O ₄ ) 80 to 500 g/L. It is characterized in that it contains 120g/L.

Hereinafter, a liftgate hinge made of an aluminum alloy material surface-treated using the high corrosion resistance surface treatment method of a liftgate hinge made of an aluminum alloy material of the present invention so that those skilled in the art can easily practice it. This will be explained in detail using examples. The method of treating the highly corrosion-resistant surface of a liftgate hinge made of an aluminum alloy material according to an embodiment of the present invention can be more clearly understood through examples described later. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein.

Surface treatment (plating) preparation

Specimen: Prepare a liftgate hinge made of aluminum alloy material.

Degreasing step (S ₁₀₀ ): Prepare a degreasing solution containing 2.5 g/L of sodium metasilicate 9-hydrate, 25 g/L of sodium carbonate, and 2 g/L of disodium ethylenediaminetetraacetic acid based on the total 1L of degreasing solution, and the remainder filled with pure water. do.

Etching step (S ₂₀₀ ): Prepare an etching solution containing 15 g/L of sodium hydroxide based on the total 1L of the etching solution and the remainder filled with pure water.

Dismut step (S ₃₀₀ ): Prepare a dismut solution containing 350 mL/L of nitric acid based on the total 1L of dismut solution and the remainder filled with pure water.

Zincate step (S ₄₀₀ ): Prepare a zincate solution containing 15g/L of iron chloride, 90g/L of nickel sulfate, 85g/L of sodium hydroxide, and 110g/L of zinc oxide based on the total 1L of zincate solution.

Zinc plating step (S ₅₀₀ ): Based on the entire 1L of zinc plating solution, 130g/L of sodium hydroxide, 12g/L of zinc oxide, N,N'-bis[3-(dimethylamino)propyl] and 1,1'-oxy Prepare a zinc plating solution and anode zinc containing 8.5 mL/L of the bis[2-chloroethane] polymer combination and 2 mL/L of the pyridinium mixture. At this time, the pyridinium mixture is composed of 1-benzyl-pyridinium-3-carboxylate (3-carboxy-1-(phenylmethyl)pyridinium), chloride, and sodium salt mixed in a ratio of 1:1:1. use.

Zinc nickel alloy plating step (S ₆₀₀ ): Based on the entire 1L of zinc nickel alloy plating solution, 130 g/L of sodium hydroxide, 12 g/L of zinc oxide, 25 mL/L of tetraethylene pentamine, 7 g/L of nickel sulfate, and 2 mL of pyridinium mixture. Prepare zinc-nickel alloy plating solution containing /L and anode nickel. At this time, the pyridinium mixture is composed of 1-benzyl-pyridinium-3-carboxylate (3-carboxy-1-(phenylmethyl)pyridinium), chloride, and sodium salt mixed in a ratio of 1:1:1. use.

Chromate treatment step (S ₇₀₀ ): Chromate containing 10g/L of sodium hydroxide, 30mL/L of nitric acid, 450g/L of chromium nitrate (40%), 110g/L of chromium chloride, and 100g/L of oxalic acid based on 1L of total chromate solution. Prepare the liquid.

Liftgate hinge surface treated by a method according to an embodiment of the present invention

An experiment was conducted to observe the appearance of a liftgate hinge made of an aluminum alloy material with a highly corrosion-resistant surface treatment using a method according to an embodiment of the present invention. The process conditions for each process when manufacturing the experimental group are shown in Table 1 below.

Experimental group 2-1 Degreasing step
(S ₁₀₀ ) Temperature: 45℃
Time: 10 minutes Etching step
(S ₂₀₀ ) Temperature: 45℃
Time: 4 minutes Dismut stage
(S ₃₀₀ ) Temperature: 25℃
Time: 3 minutes zincate stage
(S ₄₀₀ ) Temperature: 25℃
Time: 1 minute Galvanizing step
(S ₅₀₀ ) Temperature: 25℃
Time: 10 minutes
Current intensity: 2A zinc nickel alloy
Plating step (S ₆₀₀ ) Temperature: 22℃
Time: 20 minutes
Current intensity: 2A chromate
Processing step (S ₇₀₀ ) Temperature: 55℃
Time: 60 seconds
pH: 1.8

As shown in Table 1, in experimental group 2-1, process conditions such as temperature, time, current intensity, and pH at all stages in the process of surface treatment of the liftgate hinge were set to suit the conditions defined in the present invention.

The results of observing the appearance of a liftgate hinge made of an aluminum alloy material with a highly corrosion-resistant surface treatment using a method according to an embodiment of the present invention are shown in FIG. 2 below.

Figure 2 shows the degreasing step (S ₁₀₀ ), etching step (S ₂₀₀ ), desmut step (S ₃₀₀ ), and zincate step (S ₄₀₀ ) in the process of surface treatment of the liftgate hinge made of aluminum alloy material of experimental group 2-1. ), a photo showing a leaf gate hinge undergoing surface treatment in the zinc plating step (S ₅₀₀ ), zinc nickel alloy plating step (S ₆₀₀ ), and chromate treatment step (S ₇₀₀ ).

As shown in FIG. 2, the liftgate hinge of experimental group 2-1, in which all process conditions at each stage were set to suit the conditions limited in the present invention, was surface treated through each process, and no plating adhesion defects occurred. It was confirmed that

Therefore, the highly corrosion-resistant surface treatment method for a liftgate hinge made of an aluminum alloy material according to an embodiment of the present invention applies a zinc and zinc-nickel alloy plating process to a liftgate hinge made of an aluminum alloy material after manufacturing the liftgate hinge product. When applying the painting process, it is possible to prevent the problem of the paint layer peeling off due to the oxide film (Al ₂ O ₃ ), which is a characteristic of aluminum alloy materials, and can have corrosion resistance equivalent to that of steel alloy materials, reducing the defect formation rate. It is believed that it can be reduced.

Degreasing step (S ₁₀₀ ) Surface treatment result observation experiment according to process time

An experiment was conducted to observe the appearance of a liftgate hinge made of surface-treated aluminum alloy material under the following process conditions. The process conditions for each process when manufacturing the experimental group are shown in Table 2 below.

Experimental group 3-1 Experimental group 3-2 Experimental group 3-3 Degreasing step
(S ₁₀₀ ) Temperature: 45℃
Time: 3 minutes Temperature: 45℃
Time: 10 minutes Temperature: 45℃
Time: 15 minutes Etching step
(S ₂₀₀ ) Temperature: 45℃
Time: 4 minutes Temperature: 45℃
Time: 4 minutes Temperature: 45℃
Time: 4 minutes Dismut stage
(S ₃₀₀ ) Temperature: 25℃
Time: 3 minutes Temperature: 25℃
Time: 3 minutes Temperature: 25℃
Time: 3 minutes zincate stage
(S ₄₀₀ ) Temperature: 25℃
Time: 1 minute Temperature: 25℃
Time: 1 minute Temperature: 25℃
Time: 1 minute Galvanizing step
(S ₅₀₀ ) Temperature: 25℃
Time: 10 minutes
Current intensity: 2A Temperature: 25℃
Time: 10 minutes
Current intensity: 2A Temperature: 25℃
Time: 10 minutes
Current intensity: 2A zinc nickel alloy
Plating step (S ₆₀₀ ) Temperature: 22℃
Time: 20 minutes
Current intensity: 2A Temperature: 22℃
Time: 20 minutes
Current intensity: 2A Temperature: 22℃
Time: 20 minutes
Current intensity: 2A chromate
Processing step (S ₇₀₀ ) Temperature: 55℃
Time: 60 seconds
pH: 1.8 Temperature: 55℃
Time: 60 seconds
pH: 1.8 Temperature: 55℃
Time: 60 seconds
pH: 1.8

As shown in Table 2, experimental group 3-1 set the process conditions so that the degreasing step (S ₁₀₀ ) in the process of surface treatment of the liftgate hinge was performed for a shorter time than the time limited in the present invention. On the other hand, in experimental group 3-2 and experimental group 3-3, process conditions such as the time of the degreasing step (S ₁₀₀ ) in the process of surface treatment of the liftgate hinge were set to fit the conditions limited in the present invention. When manufacturing the experimental group, process conditions such as temperature, time, current intensity, and pH of all steps except for the process conditions such as the time of the degreasing step (S ₁₀₀ ) were set to suit the conditions defined in the present invention.

In order to observe the surface treatment results according to the process time of the degreasing step (S ₁₀₀ ), the appearance of the liftgate hinge made of aluminum alloy material of experimental groups 3-1 to 3-3 surface treated under the above process conditions was observed. As shown in Figure 3 below.

Figure 3 shows the surface in the degreasing step (S ₁₀₀ ), zincate step (S ₄₀₀ ), and zinc plating step (S ₅₀₀ ) in the process of surface treatment of the liftgate hinge made of aluminum alloy material of experimental groups 3-1 to 3-3. This photo shows the leaf gate hinge being processed.

As shown in Figure 3, the liftgate hinges of experimental groups 3-2 and 3-3, where the process conditions such as the time of the degreasing step (S ₁₀₀ ) were set to suit the conditions limited in the present invention, went through each process. It was confirmed that no plating adhesion defects occurred during surface treatment, but the liftgate hinge of experimental group 3-1, in which the process conditions were set so that the degreasing step (S ₁₀₀ ) was performed for a shorter time than the time limited in the present invention, had a degreasing time. As it was short and partially degreased, it was confirmed that poor plating adhesion occurred during surface treatment through each process.

Therefore, the highly corrosion-resistant surface treatment of the liftgate hinge made of an aluminum alloy material according to an embodiment of the present invention is partially degreased by immersing the liftgate hinge in a degreasing solution for 10 to 15 minutes in the degreasing step (S ₁₀₀ ). It is believed that by preventing degreasing, it is possible to ultimately produce a liftgate hinge with improved plating adhesion and excellent corrosion resistance.

Etching step (S ₂₀₀ ) Surface treatment result observation experiment according to process time

An experiment was conducted to observe the appearance of a liftgate hinge made of surface-treated aluminum alloy material under the following process conditions. The process conditions for each process when manufacturing the experimental group are shown in Tables 3 and 4 below.

Experimental group 4-1 Experimental group 4-2 Experimental group 4-3 Degreasing step
(S ₁₀₀ ) Temperature: 45℃
Time: 10 minutes Temperature: 45℃
Time: 10 minutes Temperature: 45℃
Time: 10 minutes Etching step
(S ₂₀₀ ) Temperature: 45℃
Time: 30 seconds Temperature: 45℃
Time: 1 minute Temperature: 45℃
Time: 2 minutes Dismut stage
(S ₃₀₀ ) Temperature: 25℃
Time: 3 minutes Temperature: 25℃
Time: 3 minutes Temperature: 25℃
Time: 3 minutes zincate stage
(S ₄₀₀ ) Temperature: 25℃
Time: 1 minute Temperature: 25℃
Time: 1 minute Temperature: 25℃
Time: 1 minute Galvanizing step
(S ₅₀₀ ) Temperature: 25℃
Time: 10 minutes
Current intensity: 2A Temperature: 25℃
Time: 10 minutes
Current intensity: 2A Temperature: 25℃
Time: 10 minutes
Current intensity: 2A zinc nickel alloy
Plating step (S ₆₀₀ ) Temperature: 22℃
Time: 20 minutes
Current intensity: 2A Temperature: 22℃
Time: 20 minutes
Current intensity: 2A Temperature: 22℃
Time: 20 minutes
Current intensity: 2A
chromate
Processing step (S ₇₀₀ ) Temperature: 55℃
Time: 60 seconds
pH: 1.8 Temperature: 55℃
Time: 60 seconds
pH: 1.8 Temperature: 55℃
Time: 60 seconds
pH: 1.8

As shown in Table 3, in Experimental Group 4-1, Experimental Group 4-2, and Experimental Group 4-3, the etching step (S ₂₀₀ ) was performed for a shorter time than the time limited in the present invention during the surface treatment of the liftgate hinge. Process conditions were set as much as possible.

Experimental group 4-4 Experimental group 4-5 Experimental group 4-6 Degreasing step
(S ₁₀₀ ) Temperature: 45℃
Time: 10 minutes Temperature: 45℃
Time: 10 minutes Temperature: 45℃
Time: 10 minutes Etching step
(S ₂₀₀ ) Temperature: 45℃
Time: 3 minutes Temperature: 45℃
Time: 5 minutes Temperature: 45℃
Time: 10 minutes Dismut stage
(S ₃₀₀ ) Temperature: 25℃
Time: 3 minutes Temperature: 25℃
Time: 3 minutes Temperature: 25℃
Time: 3 minutes zincate stage
(S ₄₀₀ ) Temperature: 25℃
Time: 1 minute Temperature: 25℃
Time: 1 minute Temperature: 25℃
Time: 1 minute Galvanizing step
(S ₅₀₀ ) Temperature: 25℃
Time: 10 minutes
Current intensity: 2A Temperature: 25℃
Time: 10 minutes
Current intensity: 2A Temperature: 25℃
Time: 10 minutes
Current intensity: 2A zinc nickel alloy
Plating step (S ₆₀₀ ) Temperature: 22℃
Time: 20 minutes
Current intensity: 2A Temperature: 22℃
Time: 20 minutes
Current intensity: 2A Temperature: 22℃
Time: 20 minutes
Current intensity: 2A chromate
Processing step (S ₇₀₀ ) Temperature: 55℃
Time: 60 seconds
pH: 1.8 Temperature: 55℃
Time: 60 seconds
pH: 1.8 Temperature: 55℃
Time: 60 seconds
pH: 1.8

As shown in Table 4, experimental group 4-4, experimental group 4-5, and experimental group 4-6 had process conditions such as the time of the etching step (S ₂₀₀ ) in the process of surface treatment of the liftgate hinge limited in the present invention. It was set to suit the conditions. When manufacturing the experimental group, process conditions such as temperature, time, current intensity, and pH of all steps, except for the process conditions such as the time of the etching step (S ₂₀₀ ), were set to suit the conditions defined in the present invention.

In order to observe the surface treatment results according to the process time of the etching step (S ₂₀₀ ), the appearance of the liftgate hinge made of aluminum alloy material of experimental groups 4-1 to 4-6 surface treated under the above process conditions was observed. The same as Figure 4 below.

Figure 4 is a photograph showing the leaf gate hinge being surface treated in the etching step (S ₂₀₀ ) in the process of surface treating the lift gate hinge made of aluminum alloy material of experimental groups 4-1 to 4-6.

As shown in FIG. 4, the etching progressed sufficiently for the liftgate hinges of experimental groups 4-4 to 4-6 where the process conditions, such as the time of the etching step (S ₂₀₀ ), were set to suit the conditions defined in the present invention. It was confirmed that plating adhesion defects did not occur as the surface was treated through a later process, but the process conditions were set so that the etching step (S ₂₀₀ ) was performed for a shorter time than the time limited in the present invention. Experimental groups 4-1 to 4- It was confirmed that the liftgate hinge in Figure 3 had insufficient etching due to the short etching time, resulting in poor plating adhesion.

Therefore, the highly corrosion-resistant surface treatment of the liftgate hinge made of an aluminum alloy material according to an embodiment of the present invention improves plating adhesion when the plated body is immersed in an etching solution for 3 to 10 minutes and etched in the etching step (S ₂₀₀ ). It is believed that it is possible to produce a liftgate hinge with improved and excellent corrosion resistance.

Dismut stage (S ₃₀₀ ) Surface treatment result observation experiment according to process time

An experiment was conducted to observe the appearance of a liftgate hinge made of surface-treated aluminum alloy material under the following process conditions. The process conditions for each process when manufacturing the experimental group are shown in Table 5 below.

Experimental group 5-1 Experimental group 5-2 Experimental group 5-3 Degreasing step
(S ₁₀₀ ) Temperature: 45℃
Time: 10 minutes Temperature: 45℃
Time: 10 minutes Temperature: 45℃
Time: 10 minutes Etching step
(S ₂₀₀ ) Temperature: 45℃
Time: 4 minutes Temperature: 45℃
Time: 4 minutes Temperature: 45℃
Time: 4 minutes Dismut stage
(S ₃₀₀ ) Temperature: 25℃
Time: 30 seconds Temperature: 25℃
Time: 2 minutes Temperature: 25℃
Time: 4 minutes zincate stage
(S ₄₀₀ ) Temperature: 25℃
Time: 1 minute Temperature: 25℃
Time: 1 minute Temperature: 25℃
Time: 1 minute Galvanizing step
(S ₅₀₀ ) Temperature: 25℃
Time: 10 minutes
Current intensity: 2A Temperature: 25℃
Time: 10 minutes
Current intensity: 2A Temperature: 25℃
Time: 10 minutes
Current intensity: 2A zinc nickel alloy
Plating step (S ₆₀₀ ) Temperature: 22℃
Time: 20 minutes
Current intensity: 2A Temperature: 22℃
Time: 20 minutes
Current intensity: 2A Temperature: 22℃
Time: 20 minutes
Current intensity: 2A chromate
Processing step (S ₇₀₀ ) Temperature: 55℃
Time: 60 seconds
pH: 1.8 Temperature: 55℃
Time: 60 seconds
pH: 1.8 Temperature: 55℃
Time: 60 seconds
pH: 1.8

As shown in Table 5, experimental group 5-1 set the process conditions so that the dismut step (S ₃₀₀ ) was performed for a shorter time than the time limited in the present invention during the surface treatment of the liftgate hinge, and experimental group 5-1 2 and 5-3 were set so that the process conditions, such as the time of the desmut step (S ₃₀₀ ) in the process of surface treatment of the liftgate hinge, were suitable for the conditions defined in the present invention. When manufacturing the experimental group, process conditions such as temperature, time, current intensity, and pH of all steps except for the process conditions such as the time of the dismut step (S ₃₀₀ ) were set to suit the conditions limited in the present invention.

In order to observe the surface treatment results according to the process time of the dismut stage (S ₃₀₀ ), the appearance of the liftgate hinge made of aluminum alloy material of experimental groups 5-1 to 5-3 surface treated under the above process conditions was observed. is shown in Figure 5 below.

Figure 5 is a photograph showing the leaf gate hinge being surface treated in the desmut step (S ₃₀₀ ) in the process of surface treating the lift gate hinge made of aluminum alloy material of experimental groups 5-1 to 5-3.

As shown in Figure 5, the liftgate hinges of experimental groups 5-2 and 5-3, where the process conditions such as the time of the desmut step (S ₃₀₀ ) were set to suit the conditions limited in the present invention, had a smut component. It was confirmed that plating adhesion defects did not occur as it was effectively removed and surface treated through a later process, but the process conditions were set so that the desmut step (S ₃₀₀ ) was performed for a shorter time than the time limited in the present invention. Experimental group 5-1 It was confirmed that the liftgate hinge had a short desmut time and was not completely removed, resulting in poor plating adhesion during the subsequent plating process.

Therefore, the highly corrosion-resistant surface treatment of a liftgate hinge made of an aluminum alloy material according to an embodiment of the present invention involves immersing the plated body in a desmut liquid for 2 to 4 minutes in the desmut step (S ₃₀₀ ) to form smut. It is believed that if removed, it is possible to produce a liftgate hinge with improved plating adhesion and excellent corrosion resistance.

In conclusion, through Examples 1 to 5, the high corrosion resistance surface treatment method of a liftgate hinge made of an aluminum alloy material according to an embodiment of the present invention is a method of treating a liftgate hinge made of an aluminum alloy material with zinc and zinc nickel. By applying the alloy plating process, it is possible to prevent the problem of the paint layer peeling off due to the oxide film (Al ₂ O ₃ ), which is a characteristic of aluminum alloy materials, when applying the painting process after manufacturing the liftgate hinge product. It was confirmed that it can have corrosion resistance equivalent to that of alloy materials, which has the advantage of reducing the defect formation rate.

Above, the present invention has been described in detail through examples, but the present invention is not limited to the above embodiments and may be modified into various forms, and common knowledge in the field within the technical spirit of the present invention may be used. It is clear that many variations are possible depending on the person who has it. In addition, various forms of substitution, modification, and change may be made by those skilled in the art without departing from the technical spirit of the present invention as set forth in the claims, and this also falls within the scope of rights of the present invention. They will say they do it.

Claims (11)

A surface treatment method for a liftgate hinge made of aluminum alloy material,
A degreasing step of degreasing a liftgate hinge made of an aluminum alloy material, which is to be plated, by immersing it in a degreasing solution maintained at a temperature of 40 to 50° C. for 10 to 15 minutes;
An etching step of etching the plated body degreased in the degreasing step by immersing it in an etching solution maintained at a temperature of 40 to 50° C. for 3 to 10 minutes;
A desmut step of removing smut by immersing the plated body etched in the etching step in a dismut solution maintained at a temperature of 20 to 30° C. for 2 to 4 minutes;
A zincate step of substituting and precipitating zinc by immersing the plated body from which smut has been removed in the dismut step in a zincate solution maintained at a temperature of 20 to 30° C. for 50 to 90 seconds;
A zinc plating step of electroplating the plated body from which zinc has been deposited in the zincate step using a zinc plating solution at a temperature of 20 to 30° C. for 8 to 12 minutes at a current intensity of 1 to 2 A;
A zinc nickel alloy plating step of electroplating the plated body zinc plated in the zinc plating step using a zinc nickel alloy plating solution at a temperature of 18 to 25° C. for 15 to 25 minutes at a current intensity of 1 to 2 A; and
In the zinc nickel alloy plating step, the zinc nickel alloy plated body is immersed in a chromate solution with a pH of 1.6 to 2.0 and a temperature maintained at 50 to 60°C for 30 to 90 seconds to form a chromate film on the surface of the plated body. Characterized by including a processing step;
The degreasing liquid in the degreasing step contains 2 to 3 g/L of sodium metasilicate nonahydrate 9Hydrate, 23 to 27 g/L of sodium carbonate, and disodium ethylenediaminetetraacetic acid (based on the total 1L of degreasing liquid). EDTA-2Na, Ethylene diamine tetra acetic acid-disodium) is characterized in that it contains 1 to 3 g/L,
The etching solution in the etching step is characterized in that it contains 10 to 20 g/L of sodium hydroxide based on 1 L of the entire etching solution,
The dismut solution in the dismut step is characterized in that it contains 300 to 400 mL/L of nitric acid based on 1 L of the dismut solution.
The zincate liquid in the zincate step contains 10 to 20 g/L of iron chloride, 80 to 100 g/L of nickel sulfate, and 70 to 100 g of sodium hydroxide based on the entire 1L of zincate liquid. /L and zinc oxide (Zinc oxide) 100 to 120 g / L,
The zinc plating solution in the zinc plating step contains 120 to 140 g/L of sodium hydroxide, 10 to 14 g/L of zinc oxide, and N,N'-bis[3] based on the entire 1L of zinc plating solution. -(dimethylamino)propyl] and 1,1'-oxybis[2-chloroethane] polymer combination 7 to 10 mL/L and pyridinium mixture 1 to 3 mL/L, wherein the pyridinium mixture 1-Benzyl-pyridinium-3-carboxylate(3-Carboxy-1-(phenylmethyl)pyridinium), It is characterized by being composed of chloride and sodium salt mixed in a ratio of 1:1:1.
The zinc nickel alloy plating solution in the zinc nickel alloy plating step contains 120 to 140 g/L of sodium hydroxide, 10 to 14 g/L of zinc oxide, and tetraethylene based on 1 L of the entire zinc nickel alloy plating solution. It is characterized in that it contains 20 to 30 mL/L of tetraethylenepentamine, 6 to 8 g/L of nickel sulfate, and 1 to 3 mL/L of pyridinium mixture, wherein the pyridinium mixture is 1-benzyl-pyridinium- 3-Carboxylate (3-Carboxy-1-(phenylmethyl)pyridinium) (1-Benzyl-pyridinium-3-carboxylate(3-Carboxy-1-(phenylmethyl)pyridinium)), Chloride and sodium salt ( It is characterized by being composed of sodium salt) mixed in a ratio of 1:1:1.
The chromate solution in the chromate treatment step contains 8 to 12 g/L of sodium hydroxide, 25 to 35 mL/L of nitric acid, and 400 to 500 g/L of chromium nitrate based on the total 1 L of the chromate solution. , A highly corrosion-resistant surface treatment method for a liftgate hinge made of an aluminum alloy material, characterized in that it contains 100 to 120 g/L of chromium chloride and 80 to 120 g/L of oxalic acid. delete delete delete delete delete delete delete delete delete delete