KR20150084452A - Manufacturing method for porous copper - Google Patents

Abstract

The present invention relates to a method to manufacture porous copper comprising: a step of dissolving copper (Cu) under a gas atmosphere in atmospheric pressure; a step of dissolving metal for an alloy; a step of adding the dissolved metal for the alloy to the dissolved copper; a step of injecting the dissolved copper, to which the metal for an alloy is added, into a mold; and a step of forming a pore inside the copper by solidifying the copper injected into the mold. The present invention has an effect of changing a size of a pore and the porosity of porous metal by changing a type or adding an amount of metal added to dissolve copper when the porous metal is manufactured.

Description

{Manufacturing method for porous copper}

The present invention relates to a porous copper manufacturing method, and more particularly, to a method of manufacturing porous copper that can produce porous copper having a desired porosity and pore size by changing the kind and amount of metal added to the copper dissolved in the production of porous copper And a manufacturing method thereof.

Porous metallic materials are attracting attention as one of functional materials different from conventional structural materials which generally require strength. These porous metal materials have irregularly or regularly dispersed pores in a portion of their volume, and thus have a large specific surface area, light weight, and excellent energy absorption ability as compared with conventional bulk materials. In addition, it exhibits excellent liquid and air permeability because it shows thermal and electric conductivity different from conventional bulk materials.

Various methods such as mold casting method, continuous zone melting method, continuous casting method and centrifugal casting method can be used to control the porosity and pore size of the porous metal material .

Among the above methods, the casting method, the continuous casting method, and the continuous casting method use a large amount of hydrogen gas for adjusting the porosity and pore size. Here, since a large amount of hydrogen gas is used, the safety is low.

Also, the centrifugal casting method has a problem that the production amount of porous copper is limited to 150 g or less at a time.

As a prior art to the present invention, it is possible to exemplify the registered patent 10-0216483.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above problems, and it is an object of the present invention to provide a porous copper manufacturing method capable of changing porosity and pore size of a porous metal by changing kinds and addition amounts of metals added to copper dissolved in the production of porous metal .

According to an aspect of the present invention, there is provided a method of manufacturing porous copper, comprising: dissolving copper in a gas atmosphere at atmospheric pressure; Dissolving a metal for alloying; Adding the molten copper dissolved metal to the alloy; Injecting the molten copper to which the metal for alloying is added into a mold; And coagulating the copper injected into the mold to form pores in the copper; And a porous copper foil.

The gas may comprise hydrogen or oxygen.

The metal for the alloy may include aluminum (Al) or silicon (Si).

The alloy metal may be added in an amount of 0.01 to 0.1 at%.

In the molten copper implant, the copper temperature may be between 1100 and 1200 < 0 > C.

The present invention can change the porosity and pore size of the porous metal by changing the kind and addition amount of the metal added to the copper dissolved in the production of the porous metal.

1 is a flow chart showing a configuration of a porous copper manufacturing method according to the present invention.
2 is a view showing a constitution of an example of a centrifugal casting apparatus used in the present invention.
Figure 3 is a diagram showing that the added aluminum acts as a pore nucleation site.
4 is a view showing an example of a specimen of a porous copper structure manufactured by the present invention.
5 is a cross-sectional view showing the pore structure of the porous copper sample shown in FIG.
6 is a graph showing the pore size distribution of the porous copper sample according to the change in aluminum addition amount.
7 is a graph showing the porosity change of the porous copper sample according to the change in aluminum addition amount.
8 is a graph showing a change in the average pore diameter of the porous copper based on the change in aluminum addition amount.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart showing a configuration of a porous copper manufacturing method according to the present invention.

Referring to FIG. 1, a porous copper manufacturing method according to the present invention includes a copper dissolution step S110, a metal dissolution step S120 for an alloy, an addition step S130, a step of injecting into a mold S140, S150).

The porous copper manufacturing method according to the present invention can be performed by centrifugal casting. Here, centrifugal casting is a casting method in which molten copper is flowed while rotating the mold, and casting is performed using centrifugal force. Further, a centrifugal casting apparatus can be used for this purpose. However, centrifugal casting is one of the various methods used for carrying out the present invention, and the present invention can also be carried out by processes other than centrifugal casting.

First, the centrifugal casting apparatus used in the present invention will be described.

2 is a view showing a constitution of an example of a centrifugal casting apparatus used in the present invention.

2, the centrifugal casting apparatus 10 includes a main body 11 having a substantially cylindrical shape, a rotation shaft 13 disposed at an inner center thereof, and components to be described later disposed therein; An induction furnace 16 for dissolving the copper, an infrared ray temperature detector IR for measuring the heat of the induction melting furnace 16, an induction coil 18 for applying heat to the induction melting furnace 16, A mold 20 disposed rotatably with respect to the rotary shaft 13 and injected with copper dissolved in the induction melting furnace 16, a counterweight 14 disposed on the opposite side of the mold 20 with respect to the rotation axis, And a cooling section 22 for coagulating the copper injected into the cooling section 20.

Here, the mold 20 is connected to the center shaft by the mold connecting rod 17, and the mold connecting rod 17 allows the distance between the mold 20 and the rotational shaft to be changed according to the user's need. It is also preferable that the balance weight connecting rod 15 connecting the balance weight 14 and the central axis is also configured to change the distance between the balance weight 14 and the central axis in response to a change in distance between the mold 20 and the center axis .

The main body 11 is connected to a gas supply part 30 for forming a gas atmosphere. Here, the gas supply unit 30 includes a hydrogen tank and an argon tank for forming a hydrogen atmosphere. However, in this embodiment, the gas supply unit 30 includes a hydrogen tank and an argon tank. This is because the use of hydrogen is suitable for dissolving copper, so that the gas supply unit 30 may contain oxygen in addition to H ₂ O, CH ₄ , and SO ₂ And may include all gases that can be dissolved in copper.

In the present invention, the gas supply unit 30 may include various kinds of gases, but in the present embodiment, it is assumed that hydrogen or oxygen is used to form the gas atmosphere. When the gas is supplied from the gas supply unit 30, the supply pressure is measured and displayed by the pressure gauge 21.

The induction melting furnace 16 can inject the molten copper into the mold 20 through an injection port (not shown) formed at one side thereof.

In the case of copper dissolution, the infrared thermometer (IR) measures whether the temperature of the induction furnace 16 is appropriate.

Referring again to FIG. 1, the present invention will be described.

The copper dissolution step (S110) is a step of dissolving copper as a raw material of the porous copper to be produced by the user. The copper dissolution step (S110) is preferably performed in an oxygen or hydrogen atmosphere at atmospheric pressure.

 However, since the atmospheric pressure may vary somewhat depending on the weather conditions, it is preferable that the pressure of the hydrogen gas in the main body 11 is maintained at a level of 0.1 MPa (megapascals), that is, a standard atmospheric pressure. At this time, the pressure of the gas inside the main body 11 is maintained at 0.1 MPa (megapascals), even if a gas other than hydrogen is used for gas atmosphere formation.

Here, the following steps are performed in order to prevent other gas components from being mixed when forming the hydrogen gas atmosphere in the main body.

First, air inside the main body 11 is discharged using a vacuum pump 12 to form a vacuum of 10 ^-2 Torr. Then, an inert gas such as argon is injected. Then, the vacuum pump 12 is operated to form a vacuum of 10 ^-2 Torr. The process of discharging is repeated several times to minimize the amount of air in the main body.

When the inert gas is injected and discharged several times and the air inside the body is minimized, hydrogen gas is injected. At this time, hydrogen gas is injected into the main body 11 to form a hydrogen atmosphere of 0.1 MPa.

The copper dissolved in the copper dissolution step (S110) contains pure copper (Cu) with a purity of 99.99 at%. The copper dissolution proceeds in the induction melting furnace 16 connected to the induction melting furnace 16. And, the amount of the molten copper is 150 g, but it can be changed according to the size of the induction melting furnace 16 and the purpose of the user. The melting temperature of the copper is preferably 1423K to 1473K.

The step of dissolving the metal for alloying (S120) comprises preparing and dissolving a metal for alloying added to set porosity and porosity. Here, the metal for alloying to be added may include aluminum (Al) or silicon (Si).

Fig. 3 is a view showing that the added aluminum acts as a pore nucleation site. Fig. 3 is a view for explaining that aluminum is added for pore formation. Fig.

Referring to FIG. 3, when aluminum is added, the added aluminum acts as pore nucleation sites that form pores in the porous copper surroundings, allowing small pores of dense distribution to be formed. Pore nucleation sites can occur between porous copper and the surface of nonmetallic inclusions such as oxides in molten copper. The aluminum used in the present invention reacts with residual oxygen in the molten metal to produce aluminum oxide, which can act as a pore nucleation site.

FIG. 3 (b) shows a case where the amount of aluminum added is increased as compared with that of FIG. 3 (a). As the amount of aluminum oxide increases, the number of pore nucleation sites also increases, thereby increasing the number of pores.

The adding step (S130) is a step of adding a metal for alloying in a dissolved porous copper dissolved state. Here, the addition amount of the metal for the alloy is preferably 0.01 to 0.1 at%, more preferably 0.01 to 0.02 at%. The addition amount is calculated on the basis of 150 or 200 g of pure copper.

The following [Table 1] shows an example of the addition amount of aluminum, for example.

In addition, when the metal for alloying is added, the molten copper temperature is preferably 1100 to 1200 ° C.

The copper injection step (S140) is a step of injecting the molten copper to which the alloy metal is added into the mold (20).

When the copper injecting step (S140) is performed, the rotating shaft 13 is preferably rotated at a speed of 200 to 1000 rpm. When the rotary shaft 13 rotates, the mold 20 disposed in the main body 11 also rotates at the same speed in conjunction with this rotation, facilitating copper injection into the mold 20. Here, the rotation speed of the rotary shaft 13 is limited to a predetermined range, but it may be 1000 rpm or more according to the user's need. However, the minimum speed is preferably 200 rpm.

At this time, the mold 20 is preferably made of a 0.1 mm thick stainless steel plate material. This is to facilitate coin one-way solidification injected into the mold 20.

After the copper injection is performed in the mold 20, the pore forming step (S150) proceeds.

The pore forming step S150 is a step of reducing the temperature inside the main body 11 to below the copper melting temperature and at the same time rotating the mold 20 at a predetermined speed for about one- Allow the copper to solidify. Further, it is preferable that, after the coagulation solidification is completed, the main body 11 is not opened for 10 to 20 minutes to prevent oxidation of the surface, and the furnace cooling is performed.

Here, before the pore formation step (S150), adjustment of the distance between the mold (20) and the rotary shaft (13), that is, adjustment of the radius of rotation of the mold (20) is completed according to the user's need. The turning radius of the mold 20 is preferably 175 mm to 195 mm. As the radius of rotation of the mold 20 increases, a larger centrifugal force may be applied to the pores formed in the copper to reduce the porosity and pore diameter, so that the user adjusts the appropriate radius of rotation according to the required porosity and pore diameter .

During the pore formation step S150, the rotational speed of the rotating shaft 13 may vary according to the need of the user, that is, the porosity and diameter of the pores to be obtained by the user.

Therefore, the user preferably controls the rotation speed and the turning radius according to the porosity and the diameter of the required pores.

When the rotation of the main body 11 is completed, the cooling unit 22 is operated for 10 to 20 minutes to prevent the copper surface from being oxidized.

Thereafter, the gas in the main body 11 is removed, and the main body 11 is opened to release the vacuum, whereby the porous copper having the pores having the directionality can be obtained. Here, the pores may be formed toward the rotation axis 13 of the mold.

According to the centrifugal casting machine and the centrifugal casting method, the following porous copper structures can be obtained.

FIG. 4 is a view showing an example of a specimen of a porous copper structure manufactured by the present invention, and FIG. 5 is a cross-sectional view showing a porous form of the porous copper specimen shown in FIG.

Referring to FIG. 4, it can be seen that the specimen has a rectangular parallelepiped shape. The shape of the specimen is in the form of a rectangular parallelepiped to facilitate description of the direction of the pore, but may be formed in other forms according to the needs of the user.

Referring to FIG. 5, (a) to (e) of FIG. 5 show that the pore size and the porosity are changed according to the change in the amount of aluminum added as an alloy.

5 (a) to 5 (e) consist of a plurality of columns. Here, the views of the upper row (i) are diagrams showing a section taken along the direction perpendicular to the solidification direction and cut at the center portion of the ingot, which corresponds to the sectional view taken along the line ii of FIG. 4, Sectional view of the ingot center portion cut in a horizontal direction and corresponds to a sectional view taken along the line ii-ii of Fig.

5 (b) to 5 (e) show aluminum specimens of 0.01, 0.02, 0.05 and 0.1 at%, respectively, It is the form of the added specimen.

It can be seen from the above figure that the size and distribution of pores vary depending on the amount of aluminum added. In particular, it can be seen that the distribution of small pores is large based on the addition amount of aluminum of 0.02 at%, and the pore length gradually decreases and then increases again.

Here, the porosity of the porous copper can be converted by the following equations (1) and (2).

Where ρ is the density (g / cm ³ ), n ₁ is the dry weight of the casting specimen (g), n ₂ is the weight of the casting specimen in grams (g), ρ _t is the density of water in g / cm < ³ >). The density of the cast specimen was calculated by the following formula (1), and then the porosity was measured using the following formula (2).

Here, ε is a porosity (%) of the molded specimen, ρ ₀ is the specimen density (g / cm ³⁾ of a non-pore bulk (Bulk), ρ is the density (g of the cast specimen obtained in the above-described Equation 1 / cm < ³ >). The density of the bulk copper specimen was (8.94 g / cm ³ ), and the porosity was measured assuming that the bulk density of the alloying elements was not changed.

In addition, since the present experiment uses a centrifugal casting method, the porosity can be changed according to the process conditions of the centrifugal casting, but these will not be described.

6 is a graph showing the pore size distribution of the porous copper sample according to the change in aluminum addition amount.

6 (a) is a pore size distribution of a specimen made of pure copper without adding aluminum, and FIGS. 6 (b) to 6 (e) the pore size distribution of the specimen added at.

Further, according to FIG. 6, when aluminum was added at 0.02 at%, the pore size distribution of fine size was high, and the larger the pore size distribution was, the larger the pore size distribution was.

7 is a graph showing the porosity change of the porous copper sample according to the change in aluminum addition amount. In FIG. 7, the addition amount of aluminum is the case where aluminum is not added and aluminum is added at 0.01, 0.02, 0.05 and 0.1 at%, respectively, as shown in FIG. 5 and FIG.

Referring to FIG. 7, it can be seen that the change in porosity is insignificant even when the amount of aluminum added is changed.

8 is a graph showing a change in the average pore diameter of the porous copper based on the change in aluminum addition amount. In the figure, the inverted triangle represents the standard deviation.

Referring to FIG. 8, it can be seen that the pore diameter varies with the change in the amount of aluminum added. It can be seen that as the amount of aluminum added increases from 0 to 0.02 at%, the average pore diameter gradually decreases and the number of pores decreases or decreases. However, it can be seen that the average pore diameter increases again as the addition amount of aluminum increases from 0.02 at%.

The present invention can change the porosity and pore size of the porous metal by changing the kind and addition amount of the metal added to the copper dissolved in the production of the porous metal.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: Centrifugal casting device
11: Body 12: Vacuum pump
13: rotating shaft 16: melting furnace
18: induction coil 14: counterweight
20: mold 22: cooling section
30: gas supply unit
100: Antibacterial filter
110: Antibacterial filter body
120: Antibacterial film
130: filter paper

Claims (5)

A method of producing porous copper,
Dissolving copper (Cu) in a gas atmosphere at atmospheric pressure;
Dissolving a metal for alloying;
Adding the molten copper dissolved metal to the alloy;
Injecting the molten copper to which the metal for alloying is added into a mold; And
Allowing the copper injected into the mold to solidify to form pores in the copper; ≪ / RTI > The method according to claim 1,
Wherein the gas comprises hydrogen or oxygen. The method according to claim 1,
The metal for the alloy includes,
Aluminum (Al) or silicon (Si). The method according to claim 1,
Wherein the alloy metal is added in an amount of 0.01 to 0.1 at%. The method according to claim 1,
Wherein during the molten copper implant, the copper temperature is between 1100 and 1200 < 0 > C.

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