KR100375636B1 - A method for producing a copper plated aluminium wire - Google Patents

Abstract

The present invention relates to a copper-clad aluminum wire for forming a coating material on the outer surface of the aluminum alloy, the degreasing step of processing the aluminum alloy with a rod, and then treated with a degreasing solution containing sodium hydroxide to remove the fat and oil components; An oxide layer removing step of removing the aluminum oxide layer by etching the aluminum alloy from which the fat or oil is removed from the etching solution at a temperature of 50 to 70 ° C .; An activation treatment step of activating the aluminum alloy from which the aluminum oxide layer has been removed from the active liquid at room temperature for 0.5 to 2 minutes; A zinc layer forming step of forming a zinc coating by treating the activated aluminum alloy at room temperature for 1 to 10 minutes in a quenching solution: In a zinc layer forming step, an aluminum alloy having a zinc layer formed on an outer surface thereof at a room temperature of 1 to 10 A preplating step of forming a copper layer by plating for a minute; A neutralization step of washing the copper-plated aluminum alloy with water and then treating it with a neutralizing solution containing sulfuric acid to remove oxides of the copper plating layer; It consists of a main plating step in which an oxide-free aluminum alloy is treated in a main plating solution to form a copper layer having a desired plating thickness. The adhesion of the copper plating layer is improved, thereby improving mechanical properties such as elongation, as well as in the drawing process. The peeling phenomenon is to be blocked at the source.

Description

A method for producing a copper plated aluminum wire

The present invention relates to a copper clad aluminum wire coated with a copper layer on an outer surface of an aluminum alloy, and in particular, by removing an oxide layer of an aluminum alloy, forming a zinc layer, and then plating a copper layer, thereby improving adhesion of the copper plated layer. It relates to a method for producing a copper-clad aluminum wire that can be made.

In general, copper-clad aluminum wire is a metal material which shares not only low specific gravity of aluminum alloy but also excellent machinability such as freshness and electrical excellent property of copper. After processing, the copper is bonded to its circumferential surface.

Therefore, since copper is bonded to the surface of the aluminum alloy rod, the electrical properties are improved by the copper cladding layer while the properties of the aluminum alloy itself are maintained, for example, the electrical conductivity is smooth and the drawing process is smooth and the desired thickness is achieved. And it becomes possible to manufacture by length.

That is, in the conventional method for producing a copper-clad aluminum wire, the aluminum alloy rod as a core, copper is wrapped around it, extruded by physical force from the outside to bond copper, and then the aluminum alloy rod is bonded to the copper layer. It is known to go through a heat treatment process to improve the properties.

However, in the conventional copper-clad aluminum wire, copper is attached by physical force without removing the aluminum oxide layer existing on the outer surface of the aluminum alloy, so that the heat treatment process is necessarily added for spheroidization after the drawing process. This caused a problem of increased incidental costs.

In particular, the aluminum oxide layer is thermodynamically very stable and difficult to remove by heat treatment. As a result, an interface exists between the surface of the aluminum alloy and the copper layer. There was a problem acting as a cause.

In addition, the conventional copper-clad aluminum wire is a state in which copper is attached to the outer surface by physical force, and a bonding process between copper is indispensable, and even if the uniformity of the copper bonding layer is improved through heat treatment, There was a problem acting as a cause of the rise of resistance or cracking during the drawing process.

Accordingly, the present invention has been made to solve the above problems, by removing the aluminum oxide layer of the aluminum alloy, forming a zinc layer and then plating copper, thereby improving the electrical and mechanical properties of the aluminum alloy. It is an object of the present invention to provide a method for producing a copper clad aluminum wire.

1 is a work flow diagram showing a manufacturing process of a copper-clad aluminum wire according to the present invention,

2 is a cross-sectional view showing a copper-clad aluminum wire according to the present invention.

* Explanation of symbols for main parts of drawing

10: aluminum alloy 20: copper cladding

In the present invention for achieving the above object, in the method for producing a copper-clad aluminum wire to form a copper cladding on the outer surface of the aluminum alloy, by processing the aluminum alloy into a rod, and then degreasing with a degreasing solution containing sodium hydroxide A degreasing step of removing the oil and fat component attached to the aluminum alloy; An oxide layer removing step of removing the aluminum oxide layer by etching the aluminum alloy in which the fat is removed in the degreasing step for 1 to 3 minutes in an etching solution at a temperature of 50 to 70 ° C .; An activation treatment step of activating the aluminum alloy from which the aluminum oxide layer is removed with an active liquid at room temperature for 0.5 to 2 minutes; Zinc layer formation step of removing the residual aluminum oxide layer by zinc coating by quenching the activated aluminum alloy at room temperature for 1 to 10 minutes at room temperature: The zinc layer is formed on the outer surface in the zinc layer formation step. A preplating step of forming a copper layer on the aluminum alloy by plating the formed aluminum alloy at room temperature for 1 to 10 minutes; A copper layer having a desired plating thickness for the aluminum alloy in which the oxide is removed in the neutralization step and the neutralization step of removing the oxide formed in the copper plating layer by washing the copper-plated aluminum alloy with water and then neutralizing with sulfuric acid. It comprises a main plating step to form a. Hereinafter, the operation according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a working process diagram showing a manufacturing process of a copper-clad aluminum wire according to the present invention, Figure 2 is a cross-sectional view showing a copper-clad aluminum wire according to the present invention. By forming a copper clad material on the outer surface of the aluminum alloy according to the present invention In order to manufacture copper-clad aluminum wires that share the properties of copper while maintaining the properties of the aluminum alloy, first, the aluminum alloy is processed into a rod, and then degreased with a degreasing solution containing sodium hydroxide (NaOH) to attach to the aluminum alloy. It is necessary to remove the fatted oil component. At this time, it is preferable to use a degreasing liquid containing 10 to 40 g / L sodium hydroxide, as in the embodiment to be described later. Next, the aluminum oxide layer is etched by etching the aluminum alloy from which the oil is removed in the degreasing step Remove The etching in the oxide layer removing step is performed in an etching solution containing 10 to 50 g / l of sodium carbonate (Na ₂ CO ₃ ) and 10 to 50 g / l of sodium phosphate (Na ₃ PO ₄ ) as in the following example. It is preferable to process for 1-3 minutes at the temperature of 50-70 degreeC. In this way, the aluminum alloy from which the aluminum oxide layer was removed forms an zinc layer after an activation process. In the case of the present invention, the activation step is preferably performed at least twice. In the initial activation step, as described later, it is preferable to perform activation treatment at room temperature for 0.5 to 2 minutes in an active solution containing 40 to 70 vol% of nitric acid (NH ₃ ). The film is formed and the remaining aluminum oxide layer is removed. Preferably, as described later, zinc oxide (ZnO) is 8-12 g / l, sodium hydroxide (NaOH) is 400-600 g / l, ferric chloride (FeCl ₃ ) is 0.5-1.5 g / l, loxel salt In a zincate solution containing 5-15 g / l of (KNaC ₄ H ₄ O ₆ .4H ₂ O), a zinc layer is formed by treating the mixture at room temperature for 1 to 10 minutes. A copper layer is formed on the aluminum alloy by plating an aluminum alloy having a zinc layer formed on the surface thereof. In this pre-plating step, the plating treatment is 37.4 to 41.2 g / l of cyanide copper (CuCN), 44 to 48 g / l of cyanide (NaCN), and 2.25 to 3.95 g / of soda glass, as described later. L, sodium carbonate (Na ₃ CO ₃ · 10H ₂ O) of 19.6 to 30.0 g / l, and Rossel salt containing 30 to 60 g / l, the current density of 2 to 6 A / for 1 to 10 minutes at room temperature. It is preferable to carry out in dm2. [0034] The copper alloy aluminum alloy as described above needs to be washed with water and then treated with a neutralizing solution containing sulfuric acid to remove oxides formed in the copper plating layer. The sulfuric acid-containing neutralizing solution used in this neutralization step is preferably one containing sulfuric acid of about 15 vol%. Further, in the neutralization step, an aluminum alloy from which oxides are removed is plated and a copper layer having a desired plating thickness is finally obtained. To form. In this main plating step, as described below, copper sulfate (Cu ₂ SO ₄ ) is 180 to 250 g / l, sulfuric acid is 40 to 80 g / l, and thiourinosodium (H ₂ NCSNH ₂ ) is 0 to 0.05 g / l. In the plating solution containing 0.001 to 0.005 g / L of chlorine, plating is preferably performed at a temperature of 20 to 60 ° C and a current density of 2 to 6 A / dm 2.

Hereinafter, described in detail with reference to the accompanying table an embodiment according to the present invention.

(Example)

First, the copper-clad aluminum wire of the present invention was manufactured by processing an aluminum alloy (electric series) into a rod having a diameter of about 3 to 8 mm through a work process such as drawing, and the like.

1. Degreasing step: The step of removing foreign matters such as oil and fat component to be attached to the outer surface of the aluminum alloy in the process of the rod, was carried out under the conditions as shown in Table 1.

TABLE 1

Ingredient (g / ℓ) Temperature (℃) Minutes Remarks Sodium hydroxide lowest 10 Room temperature One Best 40 10 optimal 30 3

As shown in Table 1, when sodium hydroxide was added at 10 g / l or less, the degreasing effect was reduced, and the degreasing time was increased. When sodium hydroxide was added at 40 g / l or more, the excess sodium hydroxide eroded the aluminum alloy. It can be seen that sodium hydroxide is preferably added in an amount of about 10 to 40 g / l, in particular about 30 g / l.

In addition, as shown in Table 1, the time required for degreasing varies depending on the amount of sodium hydroxide added, but it is 1 to 10 minutes at room temperature (10 to 30 ° C), particularly on the assumption that sodium hydroxide is contained in about 10 to 40 g / L. It can be seen that keeping for about 3 minutes is preferable.

2. Oxide layer removal step: A step of completely removing foreign substances remaining on the outer surface of the aluminum alloy and removing the aluminum oxide layer, was carried out under the conditions shown in Table 2.

TABLE 2

Ingredient (g / ℓ) Temperature (℃) Minutes Remarks Soda Carbonate Sodium phosphate lowest 10 10 50 One Best 50 50 70 - optimal 25 30 60 3

As shown in Table 2, when sodium carbonate and sodium phosphate were added below 10 g / l, the etching time was insufficient to increase the etching time, whereas when added above 50 g / l, the etching was excessive and aluminum alloy was added. It is eroded.

Therefore, it can be seen that it is preferable to add sodium phosphate at about 30 g / l while adding sodium carbonate and sodium phosphate at 10 to 50 g / l, in particular, sodium carbonate at about 25 g / l.

In addition, in the case where the etching temperature of the aluminum alloy rod is 50 ° C. or lower, the etching effect is lowered even though the etching time is maintained for a long time. It is preferable to keep at about -70 degreeC about 1-3 minutes.

3. First activation step: The step of activating the aluminum surface as well as removing the aluminum oxide layer remaining on the aluminum alloy rod, the activation treatment was performed under the test conditions shown in Table 3.

TABLE 3

Component (vol.% L) Temperature (℃) Minutes Remarks nitric acid lowest 40 0.5 Best 70 2 optimal 60 Room temperature One

As shown in Table 3, the time required for the activation treatment was relatively increased when nitric acid was added at 40 vol% or less, and when it was added at 70 vol% or higher, there was a risk of explosion due to the generation of vapor. It can be seen that it is preferable to add in volume%, especially around 60 volume%.

In addition, it is understood that the time required for the activation of the aluminum alloy is preferably 30 seconds to 2 minutes at room temperature (10 to 30 ° C.), especially about 1 minute, on the assumption that 40 to 70% by volume of nitric acid is contained. there was.

4. The first zinc layer forming step: decomposing the aluminum oxide layer existing on the outer surface of the aluminum alloy and forming a zinc film to protect the aluminum oxide from further formation, and is carried out under the conditions shown in Table 4. It was.

TABLE 4

Addition amount (g / ℓ) Ingredient (g / ℓ) Temperature (℃) Minutes Zinc oxide Sodium hydroxide Ferric chloride Rotsel salt lowest 8 400 0.5 5 10 One Best 12 600 1.5 15 - 10 optimal 10 525 1.0 10 Room temperature 3

As shown in Table 4, the zincate solution contains 8-12 g / l zinc oxide, 400-600 g / l sodium hydroxide, 0.5-1.5 g / l ferric chloride, and 5-15 g / l lotose salt. It is preferred to be included. If the zinc oxide in the zinc solution is less than 8 g / l, the zinc oxide layer is insufficient in thickness and the pre-plated layer is not dense. If the zinc oxide is more than 12 g / l, the zinc oxide precipitates in the solution and becomes saturated at the bottom of the bath. . In addition, when the sodium hydroxide is less than 400g / ℓ, the effect of removing the remaining aluminum oxide on the aluminum surface is insufficient, a dense zinc layer is formed, the physical peeling phenomenon is visible before entering the pre-plating step, if the excess is more than 600g / ℓ During the etching of the known aluminum and the zinc layer formation process, the etching is continued at the boundary layer, which is the cause of the exfoliation of the zinc layer and the known aluminum, which is undesirable. If the ferric chloride is 0.5g / l or less, a multi-porous zinc layer is formed, and it is difficult to contain 1.5g / l or more. When the lotel salt is 5 g / l or less, a multi-porous zinc layer is formed, and the zinc layer is no longer densified even when 15 g / l or more is added. More preferably, zinc oxide is contained in about 10 g / l, sodium hydroxide is contained in about 525 g / l, ferric chloride is contained in about 1.0 g / l, and lotel salt is contained in about 10 g / l.

In addition, when the formation time of the zinc layer is less than 1 minute, while aluminum oxide is not sufficiently dissolved, the zinc layer is not thickly formed by being deposited for 10 minutes or more, so that it is deposited for about 3 minutes at room temperature. desirable.

5. Second Activation Step: By dissolving the zinc layer using an activating liquid having the same composition as the first activation step, the aluminum oxide layer dissolved in the zinc layer is reliably removed.

6. Second zinc layer forming step : To improve wettability of the aluminum alloy and copper in the plating step, which will be described later using a solution having the same composition as the first zinc layer forming step, ie, the plating step described later. Step.

In particular, when the plating step is performed without passing through the second zinc layer forming step, the wettability of the aluminum alloy and the copper is poor, and the phenomenon in which the coating material is peeled off during the drawing process or the bending test occurs.

7. Pre-plating step : By coating the copper layer on the zinc layer formed on the outer surface of the aluminum alloy to facilitate the growth of the copper layer, it was plated under the test conditions shown in Table 5.

TABLE 5

Amount Ingredient (g / ℓ) Temperature (℃) Minutes Current density A / dm Cheonghwa-dong Cyan soda Glass blue soda Soda Carbonate Rotsel salt lowest 37.4 44.0 2.25 19.6 30 10 One 2 Best 41.2 48.0 3.95 30.0 60 - 10 6 optimal 39.3 46.0 3.01 19.6 52.43 Room temperature 2-6 2.5-1.3

As shown in Table 5, the preplating solution contains 37.4 to 41.2 g / l of cyanide copper, 44 to 48 g / l of cyanide, 2.25 to 3.95 g / l of free cyanide, and 19.6 to 30.0 g of sodium carbonate. / l, and the lotel salt is contained at 30-60g / l.

In addition, when the pre-plating time is less than 1 minute, the thickness of the copper layer is not sufficient when the copper layer is immersed in the sulfuric acid, which is a neutralization process, while the neutralization is not smoothly performed. 2-6 minutes are preferable.

And. If the current density in the pre-plating process is 2 A / dm 2 or less, the plating layer is formed slowly, whereas in the case of 6 A / dm 2 or more, the plating surface becomes rough, the plating color becomes dark, and in severe cases burns out, the current density It is preferable to plate at 2-6 A / dm <2> for 2-6 minutes.

8. Neutralization step : A step of removing foreign substances in parallel with water washing in the pre-plating (alkaline solution) before transferring the aluminum alloy to the main plating (acid solution), and was treated under the test conditions shown in Table 6.

TABLE 6

Way Contents Sulfuric acid concentration (vol.%) Deposition time (seconds) Method 1 Water washing → neutralization → water washing 15 10 Method 2 Water washing → China → water washing → Chinese

As shown in Table 6, Method 1 proceeds to the washing process by immersing at room temperature for about 10 seconds, Method 2 is to proceed with the second neutralization process after washing the by-product formed in the first neutralization process.

In other words, the aluminum alloy plated in the pre-plating process is washed with water at least twice and neutralized to completely remove oxides, and improve the cohesion between the rod and copper in the main plating process, and the sulfuric acid concentration is 15 vol%. Maintain inside and outside

9, main plating step : as a step of growing a copper layer to the desired plating thickness of the aluminum alloy pre-plated in the alkaline solution, the main plating treatment under the composition solution and test conditions as shown in Table 7.

TABLE 7

Amount Ingredient (g / ℓ) Temperature (℃) Minutes Current density A / dm Copper sulfate Sulfuric acid Thionyozo Goat lowest 180 40 - - 20 Depends on plating thickness One Best 250 80 0.01 0.01 60 8 optimal 210 60 0.05 0.005 40 4

Here, the plating solution in the main plating step is copper sulfate (Cu ₂ SO ₄ ) is 180 to 250g / l, sulfuric acid is 40 to 80g / l, thionosodium (H ₂ NCSNH ₂ ) is 0 ~ 0.05g / l, It is preferable to use a plating solution containing chlorine at 0.001 to 0.005 g / l. The amount of sulfuric acid and copper sulfate in the plating solution is controlled by the law of addition to each other. When the amount of sulfuric acid is less than the amount of copper sulfate, the anode current is formed while the current efficiency decreases, whereas when the amount of sulfuric acid is higher than the amount of copper sulfate, the plating layer is not dense. Is formed.

In addition, when the thionosodium is added within the prescribed range, the surface of the aluminum alloy is black copper-colored, and a clean and dense plating layer is formed, whereas when it is added over the prescribed range, the plating layer is brittle and the freshness is reduced, and dark light is generated. Since a mottled pattern of is formed, it is preferable to add around 0.005 g / ℓ.

10. Subsequent process : In the main plating process, the formed aluminum alloy, which is a plating layer having a desired thickness, is finished as a final product through a surface treatment process and a drying process to prevent surface discoloration of the copper plating layer, as shown in FIG. .

Subsequently, the plated aluminum alloy is subjected to a drawing process for processing the desired diameter or length, a drying process, and a surface treatment process for heating to improve mechanical properties (elongation, strength, etc.). Will be omitted.

As described above, according to the manufacturing method of the copper-clad aluminum wire according to the present invention, by removing the oxide layer formed on the outer surface of the aluminum alloy rod, forming a zinc layer, and then plating a copper layer, the adhesion of the copper plating layer As a result, the mechanical properties such as elongation are improved, and the peeling phenomenon occurring in the drawing process is blocked at the source.

In addition, since the separate heat treatment process for removing the oxide layer of the aluminum alloy rod is omitted, the overall cost is reduced as well as the separate bonding process for bonding the covering material is omitted, thereby improving the electrical conductivity.

Claims (8)

In the method for producing a copper clad aluminum wire by forming a copper clad material on the outer surface of the aluminum alloy, A degreasing step of processing the aluminum alloy with a rod and then degreasing with a degreasing solution containing sodium hydroxide to remove oil and fat components adhering to the aluminum alloy; An oxide layer removing step of removing the aluminum oxide layer by etching the aluminum alloy in which the oil is removed in the degreasing step at an temperature of 50 to 70 ° C. for 1 to 3 minutes in an etching solution; An activation treatment step of activating the aluminum alloy from which the aluminum oxide layer is removed with an active liquid at room temperature for 0.5 to 2 minutes; Zinc layer formation step of depositing the activated aluminum alloy with zinc solution at room temperature for 1 to 10 minutes to form a zinc coating and removing the residual aluminum oxide layer: Repeating the activation treatment step and the zinc layer forming step at least two times ; A preplating step of forming a copper layer on the aluminum alloy by plating the aluminum alloy having a zinc layer formed on the outer surface in a zinc layer forming step at room temperature in a plating solution for 1 to 10 minutes; A neutralization step of washing the pre-plated aluminum alloy with water and then treating it with a neutralizing solution containing sulfuric acid to remove oxides formed on the outer surface of the copper plating layer; And And a main plating step of forming a copper layer having a desired plating thickness for the aluminum alloy in which the oxide is removed in the neutralization step. The method for producing a copper-clad aluminum wire according to claim 1, wherein the etching solution used in the oxide layer removing step contains sodium carbonate in a content of 10 to 50 g / l and sodium phosphate in a content of 10 to 50 g / l. The method according to claim 1, wherein the activating liquid used in the activating step comprises nitric acid in an amount of 40 to 70% by volume. The zincate solution according to claim 1, wherein the zincate solution used in the zinc layer forming step is zinc oxide of 8-12 g / l, sodium hydroxide 400-600 g / l, ferric chloride 0.5-1.5 g / l, Method for producing a copper-clad aluminum wire, characterized in that the cell salt is contained in the content of 5-15g / l. delete 2. The plating solution used in the pre-plating step has 37.4 to 41.2 g / l of cyanide copper, 44 to 48 g / l of cyanide, 2.25 to 3.95 g / l of free cyanide, and It is 19.6-30.0g / L, and the manufacturing method of the copper-clad aluminum wire characterized by containing Rochelle's salt in the content of 30-60g / L. The method for producing a copper-clad aluminum wire according to claim 1, wherein the washing and neutralizing treatments are performed at least twice in the neutralization step. The plating solution according to claim 1, wherein the plating solution used in the main plating step is 180-250 g / l of copper sulfate, 40-80 g / l of sulfuric acid, 0-0.05 g / l of thioureus, and 0.001-0.005 of chlorine. Method for producing a copper-clad aluminum wire, characterized in that contained in the content of g / ℓ.