KR20090126009A - Manufacturing process of high conductive carbon fibers by metal electroplating method - Google Patents

Abstract

PURPOSE: A manufacturing method for high conductive carbon fibers by metal electroplating surface treatment is provided to produce the high conductive carbon fibers by increasing the thickness of metal electroplating on the carbon fiber. CONSTITUTION: A manufacturing method for high conductive carbon fibers includes the following steps of: processing the surface with an electrolysis plating solution; applying a cathode on the carbon fibers in the plating solution; applying an anode on a metal plate; and producing the carbon fiber having high electrical conductivity by applying the current between the metal plate and the carbon fiber. The metal plate is comprised of transition metals. The metal plate is comprised of metal selected from a group consisting of platinum, copper, nickel, silver, iron, chrome, aluminum, cobalt, ruthenium and zinc.

Description

Manufacturing process of high conductive carbon fibers by metal electroplating method

The present invention relates to a method for producing a highly conductive carbon fiber by metal electroplating surface treatment, and more specifically, in the conventional method for producing carbon fiber surface treatment using an electroplating solution, the carbon fiber in the plating solution The present invention relates to a method for producing carbon fibers having high electrical conductivity by applying an anode to a metal plate and applying an electric current between the metal plate and the carbon fiber.

Carbon fiber has been applied mainly to the aerospace industry, high technology fields related to nuclear and general technology, and transportation fields such as bearings, gears, cams, and automotive fuselage. It is a promising new material that is being used even in the field of supplies.

In particular, the highly conductive carbon fiber has excellent characteristics such as heat resistance, chemical stability, electrical conductivity, electromagnetic shielding properties, biocompatibility, flexibility, and the like, and thus can be widely applied in various industrial fields. Among them, excellent conductivity is a material of surface heating element and electromagnetic interference shielding, which can be used for the purpose of preventing mutual interference of electromagnetic waves and human harmfulness of electromagnetic waves, and replace fossil fuel for solving environmental pollution problem. Research is also underway to replace graphite, which is the main material of bipolar plates, which form the basic framework of the hydrogen fuel cell stack, which is a clean energy source.

Conventionally, a method of manufacturing a highly conductive carbon fiber by reducing and depositing metal ions from a metal salt solution on a plated product to form a metal film, electrolytic plating method in which electrolytic precipitation is carried out by the whole global area, and metal ions in the solution are reduced and precipitated by a chemical agent. There has been a chemical reduction plating method and a substitution plating method in which metal ions in a solution are substituted and precipitated by a plated object.

In the case of the chemical reduction plating method, a long plating time is required, waste water is generated, and a management cost is required. In addition, the conventional carbon fiber is difficult to apply to the field requiring high electrical conductivity, such as a bipolar plate of a polymer electrolyte membrane fuel cell because the electrical conductivity is only 10 ³ ~ 10 ¹ S / ㎝.

Accordingly, the present inventors continue to research to develop a carbon fiber having a high electrical conductivity, by performing a surface treatment through electroplating, by increasing the metal plating thickness on the surface of the carbon fiber to produce a highly conductive carbon fiber The present invention has been successfully completed.

After all, an object of the present invention is to provide a method for producing a highly conductive carbon fiber by metal electroplating surface treatment.

In order to achieve the above object, the present invention provides a metal electroplating high conductive carbon fiber manufacturing method.

Specifically, the present invention is a surface treatment using an electroplating solution, but the metal electrolytic plating having a high electrical conductivity by applying a negative electrode to the carbon fiber in the plating solution, an anode to the metal plate and applying a current between the metal plate and the carbon fiber Provided is a method for producing a highly conductive carbon fiber.

In the present invention, the electroplating solution is not particularly limited according to a method generally used in the art, but preferably a sulfide-based, chloride-based and nitride-based ionized solution in an aqueous solution. It is preferable to use at least 1 type or more, such as a system metal salt individually or in parallel. More preferably, in the case of nickel plating, NiSO ₄ (250 g / ℓ) and NiCl ₂ (45 g / ℓ) may be mixed and used. In the case of copper and iron, CuSO ₄ (10 g / ℓ) and FeSO _{4 may be used.} (20 g / L) may be used alone, and H ₃ BO ₃ (45 g / L) and H ₂ SO ₄ (20 mL) may be used as the pH buffer.

In addition, the plating current density in the plating solution is preferably 5 ~ 80 ㎃ / ㎠, below 5 ㎃ / ㎠ the concentration of metal ions oxidized in the electron and anode emitted from the cathode is lowered to generate on the surface of the carbon fiber This is because the thickness of the metal film becomes thin, and if it exceeds 80 mW / cm 2, the metallization phenomenon of carbon fiber and coalescence between fibers may occur due to the introduction of excessive metal.

In addition, during electroplating, the current is preferably applied for 10 to 300 seconds. In less than 10 seconds, the concentration of metal ions oxidized from the electrons and the positrons emitted from the cathode is lowered, and if it exceeds 300 seconds, the amount of metal rapidly rises, which causes the metallization phenomenon of carbon fiber and the coordination between fibers. .

In the present invention, the thickness of the metal film plated on the surface of the carbon fiber is preferably 0.1 to 3.5 탆. When the thickness of the metal film is less than 0.1 μm, the metal film is too thin to make it difficult to measure battery conductivity, and when the thickness of the metal film is greater than 3.5 μm, the metal film becomes too thick, resulting in poor weaving and workability between fibers.

In addition, the metal plate used as the anode is preferably a transition metal, more preferably platinum (Pt), copper (Cu), nickel (Ni), silver (Ag), iron (Fe), chromium (Cr), It is preferably selected from the group consisting of aluminum (Al), cobalt (Co), ruthenium (Ru), and zinc (Zn).

The present invention also provides a highly conductive carbon fiber plated with a transition metal produced by the above method.

In the present invention, the transition metal is platinum (Pt), copper (Cu), nickel (Ni), silver (Ag), iron (Fe), chromium (Cr), aluminum (Al), cobalt (Co), ruthenium (Ru), and zinc (Zn) is preferably selected from the group consisting of, the thickness of the metal film plated on the surface of the carbon fiber is preferably 0.1 ~ 3.5㎛.

In addition, the specific resistance of the highly conductive carbon fiber plated with the transition metal is preferably 1 × 10 ⁻⁴ to 1 × 10 ⁻⁶ μm cm.

As described above, the present invention has the effect of providing a metal electroplating high conductivity carbon fiber manufacturing method and a transition metal plated high conductivity carbon fiber prepared by the above method.

Metal electroplating high conductive carbon fiber manufacturing method according to the present invention can have a high conductivity by introducing a metal on the surface of the carbon fiber and at the same time a continuous process and a stable treatment.

Hereinafter, the present invention will be described in more detail with reference to Examples.

However, the following examples are merely to illustrate the invention, but the content of the present invention is not limited by the following examples.

Experimental Example 1. Measurement of electrical conductivity of metal plated carbon fiber

In order to measure the electrical conductivity of the metal-plated carbon fiber prepared in the following examples, the dimensions of the specimen after measuring the resistance (V / I) using a 4-probe volume resistivity tester (Mitubishi Chemical Co., MCP-T610) The electrical conductivity σ was calculated using the relationship with (W × T: cross-sectional area of the fiber side; L: distance between voltage contacts).

Experimental Example 2. Confirmation of Surface Structure, Thickness Change and Characteristics of Metal Plated Carbon Fiber

Scanning electron microscope (SEM JEOL JSM0840A) and X-ray diffraction (X-ray diffraction) analysis were performed to observe the surface structure, thickness variation and characteristics of the metal-plated carbon fiber prepared in the following examples. As a generator, Rigaku Model D / MAX-III equipped with CuK _α was used.

Example 1 Preparation of Metal Plated Carbon Fiber I

Carbon fiber used in the present invention is a polyacrylonitrile (PAN) -based high-strength carbon fiber (TC-3K-36) produced by Formosa Platic Co., using long fibers desizing with acetone for 2 hours It was used after pretreatment with 0.1M HNO ₃ for 30 minutes to remove impurities on the surface before metal plating.

Metal plating of carbon fiber was carried out using an electroplating method capable of a continuous process, and a metal plate was inserted into the positive electrode and carbon fiber into the negative electrode, respectively, and electroplated at a constant speed using a voltage device.

At this time, the electroplating solution was used by mixing NiSO ₄ (250g / ℓ) and NiCl ₂ (45g / ℓ) in the case of nickel plating, CuSO ₄ (10g / ℓ) and FeSO ₄ (20g) in the case of copper and iron, respectively / l) was used alone.

The metal plate was electroplated at a current density of 20 mA / cm 2 for 30 seconds using Ni, a transition metal, and then completely dried in a dryer to prepare metal plated carbon fibers.

Table 1 shows the results of the plating film thickness and electrical conductivity of the carbon fiber prepared according to the type, current density and plating time of the transition metal used in the present invention.

Example 2 Preparation of Metal Plated Carbon Fiber Ⅱ

The same process as in Example 1 was performed, but the transition metal was plated with Ni at a current density of 20 mA / cm 2 for 40 seconds.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example 3 Preparation of Metal Plated Carbon Fiber Ⅲ

The same process as in Example 1 was performed, but the transition metal was metal-plated at a current density of 10 mA / cm 2 for 60 seconds using Ni.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example 4 Preparation of Metal Plated Carbon Fiber Ⅳ

The same process as in Example 1 was performed, but the transition metal was plated with Ni at a current density of 80 mA / cm 2 for 60 seconds.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example 5 Preparation of Metal Plated Carbon Fiber Ⅴ

The same process as in Example 1 was performed, but the transition metal was plated with a current density of 5 mA / cm 2 for 10 seconds using Cu.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example 6 Preparation of Metal Plated Carbon Fiber Ⅵ

The same process as in Example 1 was performed, but the transition metal was metal-plated at a current density of 5 mA / cm 2 for 180 seconds using Cu.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example 7 Preparation of Metal Plated Carbon Fiber Ⅶ

The same process as in Example 1 was performed, but the transition metal was plated with a current density of 30 mA / cm 2 for 30 seconds using Cu.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example 8 Preparation of Metal Plated Carbon Fiber Ⅷ

The same process as in Example 1 was performed, but the transition metal was plated with a current density of 50 mA / cm 2 for 30 seconds using Cu.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example 9 Preparation of Metal Plated Carbon Fiber Ⅸ

The same process as in Example 1 was performed, but the transition metal was plated with Fe at a current density of 60 mA / cm 2 for 20 seconds.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example 10 Preparation of Metal Plated Carbon Fiber Ⅹ

The same process as in Example 1 was performed, but the transition metal was metal-plated at a current density of 60 mA / cm 2 for 120 seconds using Fe.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example  11. Metal plated Carbon fiber  Produce ⅩⅠ

The same process as in Example 1 was performed, but the transition metal was metal plated with a current density of 40 mA / cm 2 for 300 seconds using Fe.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Example  12. Metal plated Carbon fiber  Produce XII

The same process as in Example 1 was performed, but the transition metal was metal plated with a current density of 80 mA / cm 2 for 300 seconds using Fe.

The plated film thickness and electrical conductivity were measured in the metal plated carbon fiber prepared as described above, and the results are shown in Table 1.

Comparative Example 1.

Performed in the same process as in the above example, using a transition metal, Ni, metal plating with a current mill of 0.1 ㎃ / ㎠ for 500 seconds, and measuring the thickness and electrical conductivity of the plated film from the metal-plated carbon fiber prepared The results are shown in Table 1.

Comparative example  2.

Performed in the same process as in the above embodiment, using the transition metal, Ni, metal plating with a current mill of 80 ㎃ / ㎠ for 500 seconds, and measuring the thickness and electrical conductivity of the plated film from the metal plated carbon fiber prepared The results are shown in Table 1.

Plating film thickness and electrical conductivity of metal plated carbon fiber according to the present invention division Transition metal Thickness (㎛) Specific resistance (Ωcm) Electroplating Current density (㎃ / ㎠) Time in seconds Example 1 Ni 0.53 0.83 × 10 ^-4 20 30 Example 2 0.63 0.43 × 10 ^-4 20 40 Example 3 0.45 0.81 × 10 ^-4 10 60 Example 4 1.03 3.17 × 10 ^-5 80 60 Example 5 Cu 0.14 7.08 × 10 ^-4 5 10 Example 6 1.50 0.21 × 10 ^-5 5 180 Example 7 0.91 8.02 × 10 ^-5 30 30 Example 8 1.01 1.12 × 10 ^-5 50 30 Example 9 Fe 1.30 5.12 × 10 ^-5 60 20 Example 10 2.50 0.12 × 10 ^-5 60 120 Example 11 2.94 4.12 × 10 ^-6 40 300 Example 12 3.10 2.32 × 10 ^-6 80 300 Comparative Example 1 Ni - 0.94 × 10 ^-3 0.1 500 Comparative Example 2 Ni - 5.34 × 10 ^-7 80 500

Functional graphite having a controlled graphite interlayer growth rate produced as described above induced high hydrogen storage depending on the degree of interlayer growth rate. However, when excessively increasing the increase rate, it was confirmed that the hydrogen storage value is reduced, which is the ultra-fine gas particles of hydrogen according to the increase in the pore size of the ultra-fine pores imparted to the functional graphite when the increase rate is excessively increased. It is thought that this resulted in a decrease in the storage value of. Therefore, if the appropriate interlayer growth rate is given, it is expected that high application as a hydrogen storage material for a hydrogen vehicle with an optimized hydrogen storage value is secured.

1 is a surface treatment apparatus of a metal plated carbon fiber by the electroplating method according to the present invention.

Figure 2 shows a SEM picture of the metal-plated carbon fiber according to an embodiment of the present invention, (a) is a SEM picture of the carbon fiber before the transition metal plating; (b) is a SEM (side) photograph of a transition metal (Ni) plated carbon fiber; (c) is a SEM (cross section) photograph of a transition metal (Fe) plated carbon fiber.

** Description of symbols for the main parts of the drawing **

1. Carbon fiber 2. Metal plating bath

3. Wash bath 4. Cathode rod

5. Anode metal plate 6. Dryer

7. Take-up Motor

Claims (10)

Preparation of metal electroplating high conductive carbon fiber having high electrical conductivity by surface treatment using an electroplating solution, but by applying a cathode to a carbon fiber, a cathode to a metal plate and applying a current between the metal plate and the carbon fiber in the plating solution. Way. The method of claim 1, Plating current density in the plating solution is a production method, characterized in that 5 ~ 80 ㎃ / ㎠. The method of claim 1, The electroplating method is characterized in that the current is applied for 10 to 300 seconds. The method of claim 1, The thickness of the metal film plated on the surface of the carbon fiber is 0.1 ~ 3.5㎛ manufacturing method characterized in that. The method of claim 1, The metal plate used as the anode is a manufacturing method characterized in that the transition metal. The method according to claim 1 or 5, The metal plate used as the anode is platinum (Pt), copper (Cu), nickel (Ni), silver (Ag), iron (Fe), chromium (Cr), aluminum (Al), cobalt (Co), ruthenium (Ru) ), And zinc (Zn). A highly conductive carbon fiber plated with a transition metal prepared by the method of claim 1. The method of claim 7, wherein The transition metal is platinum (Pt), copper (Cu), nickel (Ni), silver (Ag), iron (Fe), chromium (Cr), aluminum (Al), cobalt (Co), ruthenium (Ru), and Carbon fiber, characterized in that selected from the group consisting of zinc (Zn). The method of claim 7, wherein The plated metal film has a thickness of 0.1 to 3.5㎛ carbon fiber. The method of claim 7, wherein The specific resistance of the highly conductive carbon fiber plated with the transition metal is 1 × 10 ^-4 ~ 1 × 10 ^-6 Ωcm carbon fiber, characterized in that.

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