KR101503385B1 - Apparatus of coating conducting powder using electrostatic powder and method of coating by the apparatus - Google Patents

Abstract

The present invention provides an apparatus of forming conductive powder using electrostatic powder to utilize the characteristic of a metal porous body and a coating method thereof for solving problems of coating easily a contact area by excluding wet coating, performing rapid coating, causing environmental pollution, etc. The present invention includes: a support on which the metal porous body is fixed and which is charged in a first type charge; a charging unit which charges the conductive powder coated on the metal porous body in a second charge having a polarity opposite to the first type charge; a power supplying source which supplies the second type charge in the charging unit; and a powder storage which stores the conductive powder for transferring to the charging unit. The charged conductive powder is coated on the metal porous body by using electrostatic force.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive powder coating apparatus using electrostatic powder and a coating method using the same,

The present invention relates to a powder coating apparatus using electrostatic powder and a coating method thereof, and more particularly, to an apparatus for coating a porous substrate of a metal matrix with a conductive powder by dry electrostatic spraying, .

The ceramic porous body, which is mainly used as a porous carrier, has a low thermal shock resistance in spite of the high temperature stability of the ceramic material, and the manufacturing process thereof is complicated. In addition, high-temperature sintering is required, and the cost is high. In order to solve such a problem, recently, a porous base of a metal base (hereinafter referred to as a porous metal body) has been substituted for a ceramic porous body, and it is expected that the application field will be expanded as a new area utilizing the metal characteristics. The metal porous body has a three-dimensional network structure and can be used as a core material for the environment and the energy industry such as electrodes for solar cells and fuel cells, filters for environmental pollution and purification, catalyst carriers, and highly efficient heat exchange media. It is expected to increase rapidly as a core component of environmental and energy technologies such as green car, super clean ship, greenhouse gas supporting industry, large-scale hydrogen generation, distributed power generation, and production of high efficiency alternative fuel .

On the other hand, when a metal porous body is coated with a conductive powder such as a metal or a semiconductor to form a conductive coating layer, a metal porous body that exhibits properties of the conductive powder, such as catalyst characteristics, can be realized. Conventionally, the conductive coating layer is formed using a wet coating method such as wash coating, electrostatic spray, slurry coating and the like. For example, slurry coating is a method of coating a conductive porous body with a slurry in which an aqueous or non-aqueous solvent, a binder, a plasticizer, a dispersant, a surfactant, etc. are mixed at an appropriate ratio . Electrostatic spraying is performed by injecting a colloid mixed with an electrically conductive powder in an aqueous or non-aqueous solvent into a capillary nozzle with a colloid mixed with a binder, a surfactant, and the like, and applying a droplet to the metal by electrostatic force at a high voltage of several to several tens kV Is a technique of spraying onto a porous body to coat it. However, the wet coating method has various problems such as difficult coating of a large area, slow coating speed, and environmental pollution.

A problem to be solved by the present invention is to solve various problems such as easy coating of a large area by eliminating a wet coating, a coating rate is fast, causing environmental pollution, and an electrostatic powder utilizing the characteristics of a porous metal body And a coating method using the conductive powder coating apparatus.

A conductive powder coating apparatus using an electrostatic powder is characterized in that a metal porous body is fixed, a support member that is charged with a first type of charge, and a conductive powder coated on the metal porous body, Lt; RTI ID = 0.0 > second < / RTI > form of charge. A power supply for supplying the charge of the second type to the charge portion, and a powder reservoir for storing the conductive powder to be sent to the charge portion. At this time, the charge of the second type may be a negative charge or a positive charge.

In the apparatus of the present invention, the conductive powder may be used as any one of, or a combination of, a corona method, an ion implanter, and a plasma ionizer. The support may be moved in at least one of up and down, left and right, and back and forth, or it may be cylindrical and rotatable. The voltage applied to the charge portion is preferably 100 V to 10,000 KV.

In the preferred apparatus of the present invention, the average particle diameter of the conductive powder is determined by the surface state of the porous metal body, the average weight (W) of the conductive powder, (V) for spraying the conductive powder at all, a distance (D) between the charging part and the porous metal body, and an injection flow rate (F) of the conductive powder. At this time, the average particle diameter of the conductive powder is preferably 100 nm to 1 mm.

In the apparatus of the present invention, the conductive powder may be at least one selected from among a single element selected from a conductive metal or a semiconductor, or an alloy thereof (including solid solution). The conductive powder may be at least one selected from the group consisting of carbon (C), silicon (Si), a conductive polymer, iron (Fe), chromium (Cr), nickel (Ni), cobalt (Co), platinum (Pt), palladium ), Silver (Ag), and barium (Ba), or an alloy thereof (including solid solution). In addition, the porous metal body may be at least one selected from a single metal consisting of a single element or an alloy thereof (including solid solution). The metal porous body may be at least one selected from the group consisting of Fe, Ni, Al, Ti, Cu, noble metal (Ag, Au, Pt, Pd) Lt; / RTI >

In order to solve the problems of the present invention, a conductive powder coating method using an electrostatic powder is a method in which a conductive powder is charged into a powder reservoir and the porous metal body is fixed to a supporting table charged with a first type of charge. Then, a charge of a second type opposite in polarity to the charge of the first type is supplied to the charge portion from the power source. And the conductive powder stored in the powder reservoir is sent to the lower part. And the conductive powder charged with the charge of the second form is injected into the porous metal body from the charge part. At this time, the charge of the second type may be a negative charge or a positive charge.

In the method of the present invention, the conductive powder may be used in any one of, or a combination of, a corona method, an ion implanter, and a plasma ionizer. It is also possible to repeatedly perform the step of supplying the charge of the second form to the charge portion, sending the conductive powder to the charge portion, and injecting the conductive powder into the porous metal body. Further, the method may further include the step of collecting the removed conductive powder not attached to the porous metal body with the powder collecting tank.

According to the electroconductive powder coating apparatus using the electrostatic powder of the present invention and the coating method therefor, the electroconductive powder itself is coated on the porous metal body by the electrostatic powder coating method, so that it is easy to coat a large area, has a high coating speed, And the like can be solved.

1 is a schematic view for explaining a conductive powder coating apparatus using electrostatic powder according to the present invention.
2 is a flowchart showing a conductive powder coating method using the electrostatic powder according to the present invention.
3 is a photograph of a Fe-Ni porous body according to Example 1 of the present invention.
FIG. 4A is a photograph of the Fe-Ni porous body manufactured according to the embodiment 1 of the present invention by a scanning electron microscope 60 times magnification, FIG. 4B is a graph showing the composition of FIG. 4A by EDS (Energy Dispersive Spectroscopy) Graph.
Fig. 5A is a photograph of a FeCrAl-Ni porous body manufactured by the second embodiment of the present invention, which is magnified 100 times by a scanning microscope, Fig. 5B is a graph showing the composition of Fig. 5A by EDS (Energy Dispersive Spectroscopy) Graph.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

In the embodiment of the present invention, the electroconductive powder itself is coated on the porous metal body in the electrostatic powder coating method, so that the electrostatic powder that easily solves the various problems such as large-area coating is easy, coating speed is high, A conductive powder coating apparatus and a coating method therefor are proposed. To this end, a method for coating the electrostatic powder on the porous metal body will be described in detail, and a method for manufacturing the porous metal body coated with the conductive powder using the above apparatus will be described in detail. As in the embodiment of the present invention, the conductive powder itself is porous-coated by the electrostatic powder method as one of the dry coating methods, which is compared with the wet coating. Here, the electrostatic powder refers to a state in which the conductive powder is charged with positive (+) charge or negative (-) charge.

There are various ways to charge the electrostatic powder by positive (+) or negative (-) charge and ionize. For example, a corona system, an ion implanter, a plasma ionizer, and the like can all be applied. In the electrostatic precipitator using the corona method, a DC high voltage is used, a suitable inequality electric field is formed from the collector electrode to the anode electrode and the discharge electrode to the cathode electrode, and the corona discharge in the electric field is used to charge the dust in the gas. This is a device for separating and collecting the charged particles by a Coulomb force on the dust collecting pole.

Corona discharge has a positive (+) corona discharge and a negative (-) corona discharge. The secondary corona discharge has lower corona discharge initiation voltage, higher spark discharge initiation voltage, and stability than the corona discharge. A larger electric field intensity can be obtained. Therefore, a general industrial electrostatic precipitator uses a secondary corona discharge.

The positive ions and the negative ions generated by the secondary corona discharge move toward the opposite polarity electrodes. At this time, since the ionization region is limited to the discharge electrode, that is, in the vicinity of the cathode, the cation has a short-distance stroke and the anion has a long-distance stroke. Therefore, most of the dust particles are charged with anions and moved to the anode, It is called an electrode collecting electrode. In addition, the cathode, which is a cathode, emits electrons for sustained discharge. In the charging method of dust particles, ions are energized by an electric field to collide with dust particles, and ions in the gas are charged and diffused by irregular thermal motion due to the law of gas molecular motion. There is diffusion charging in which dust is adhered to dust particles. The dust particles transferred to the electrode adhere to the surface of the electrode, which is again drained or washed, and dropped and collected.

1 is a schematic view for explaining a conductive powder coating apparatus using electrostatic powder according to an embodiment of the present invention. Of course, the components of the present invention may be suitably arranged in other forms within the scope of the present invention. An example of a sub-corona method is shown in which a charge 50 is charged by positive (+) charge or negative (-) charge and then charged with negative (-) charge. In some cases, all of the above-described static corona, ion implanter, and plasma ionizing airways can be applied. At this time, the conductive powder applied to the embodiment of the present invention may be classified into three types. That is, the conductive powder is substantially the same material as the uncharged conductive powder, the charged conductive powder, and the neutralized conductive powder, and reference numerals 32, 52, and 76, respectively.

1, the coating apparatus of the present invention includes a powder reservoir 30, a charging unit 50, and a support table 60 in a chamber 10, and includes a powder collecting tank 70 outside the chamber 10 . Optionally, the powder collecting bath 70 may be inside the chamber 10. The conductive powder 32 stored in the powder reservoir 30 is transferred to the charging unit 50 along the transfer pipe 34 by the blower 20 such as a gas blower. The charge section 50 receives a negative charge from a power supply 40 and allows negative charge to be received in the transferred conductive powder 32. The negative conductive powder 52 is injected by the action of an electrostatic force toward the surface of the porous metal body 62 which is grounded and positively charged.

If the charge section 50 is a positive corona, the electrostatic powder is charged with a positive charge. Charged positive (+) and negative (-) charges can be charged with multiple ions by singly, doubly, or trivalently. At this time, the support table 60 can be moved left and right, front and rear, up and down with respect to the center of the bottom surface of the chamber 10, and a cylindrical shape capable of rotating in the ground direction as the case may be.

A part of the charged conductive powder 52 reaching the porous metal body 62 is coated on the porous metal body 62 disposed on the support 60 and the remaining uncoated conductive powder 76 is coated on the porous porous body 62 outside the chamber 10 And is collected in the powder collecting tank 70. The collected conductive powder 76 may be transferred to the powder reservoir 30 for recycling. At this time, the uncoated conductive powder 76 is dropped to the bottom. The removed conductive powder 76 is sucked through the suction port 74 using a suction motor 72 for transferring to the powder collecting tank 70 and stored in the powder collecting tank 70.

The conductive powder 32 applied to the embodiment of the present invention may be any single element selected from among all types of metals or semiconductors which are conductive in powder form, or alloys thereof (including solid solution). For example, the conductive powder 32 may be selected from the group consisting of carbon (C), silicon (Si), conductive polymer, iron (Fe), chromium (Cr), nickel (Ni), cobalt (Co), platinum Pd), gold (Au), silver (Ag), barium (Ba), or an alloy of FeAl, FeNi, FeCr, FeCrAl and the like. More preferably, the metals and their alloys are even better. The conductive powder 32 may be manufactured by any method known in the art, and is not necessarily limited thereto.

The average particle diameter of the charged conductive powder 52 is determined based on the surface state of the porous metal body 62 and the charged particle size of the charged conductive powder ( 52, the injection speed V for injecting the charged conductive powder 52, the distance D between the charging part 50 and the metal porous body 62, and the injection flow rate F . The charged conductive powder 52 is substantially the same except for the difference between the non-charged conductive powder 32 and the charged powder. Here, the distance D refers to a horizontal distance parallel to the bottom surface of the chamber 10. Specifically, assuming that the injection time T and the average weight W of the conductive powder are constant in the same porous metal body 62, in order to obtain the desired coating layer, the injection speed V is increased or the distance D is small The size of the contained conductive powder 52 may be relatively small.

The jetting speed V can be determined by the applied voltage KV applied between the charging part 50 and the metal porous body 62 and the secondary speed at which the wind speed of the blower 20 affects the charging part 50 have. Further, the injection flow rate F can be adjusted by using the average weight W and the injection speed V. [ At this time, the injection time T and the average weight W of the conductive powder can be determined in advance. For example, the Ni metal porous body 62 having a pore size of 1,200 占 퐉 has a spraying time T of 15 seconds, an average weight W of 0.1 g / cm2 and an ejecting speed V of 50 m2 / And the distance D is 10 cm to 50 cm, the average particle diameter of the conductive powder 52 is preferably 100 nm to 1 mm.

When the average particle diameter of the conductive powder 52 is less than 100 nm, the amount of charge charged in the conductive powder 52 in the charge section 50 is small and the adhesion yield drops because it flows down without adhering to the porous metal body 62. If the average particle diameter of the conductive powder 52 is larger than 1 mm, the tendency of the metal powder to fall to the bottom of the chamber 10 due to gravity does not reach the porous metal member 62, and the adhesion yield is lowered. The applied voltage (KV) may range from 100V to 10,000KV. When the applied voltage (KV) is less than 100 V, the amount of charge charged in the conductive powder 52 in the charging part 50 is small and it is not attached to the metal porous body 62, The yield drops. Also, if it is greater than 10,000 KV, the voltage is too high, which can lead to a dangerous situation for the safety of work. Accordingly, when the stability of the operation is ensured, a higher voltage may be applied.

The charged conductive powder 52 applied to the embodiment of the present invention contains a negative charge applied in the charge section 50. [ Here, the amount containing the negative (-) charge is called charge amount. If the charged conductive powder 52 is a positive charge, it is a charge amount containing a positive charge. On the other hand, the charge amount of the conductive powder 52 of the same size varies depending on the kind of the conductive powder 52, and in particular, the charge amount is larger than that of the insulating powder.

When charge is applied to powder sprayed with free positive (+) ions or free electrons (-) generated by high voltage, the charge amount varies depending on the size and type of powder, and the charge amount determines the kinetic energy amount of powder Energy is required so that the powder can be attached to the surface of the porous metal body. When the charged powder adheres to the surface of the porous metal body, the opposite charge is generated on the surface of the porous metal body, and this is called a "mirror charge effect". By this effect, the conductive powder adheres to the surface. Insulation powder is difficult to charge because of its high electrical resistance. Since the charge amount of the conductive powder 52 is larger than that of the insulating powder as described above, the adhesive force to be adhered to the positively charged metal porous article 62 is larger than that of the insulating powder.

Meanwhile, the conductive powder (32) of the present invention is a dry coating method in which the powder itself is charged and supplied to the porous metal body (62). However, conventionally used slurry coatings include additives such as an aqueous or non-aqueous solvent, a binder, a plasticizer, a dispersant, and a surfactant in the powder. Due to the above additives, the conventional wet coating has various problems such as difficult coating of a large area, slow coating speed, and environmental pollution. However, since the electrostatic powder coating method of the present invention is one of the dry coating methods, it is possible to solve all the problems caused by the conventional additives because there is no such additive.

The porous metal body 62 can be variously formed within the scope of the present invention, and is preferably a three-dimensional network, metal fiber mat or honeycomb. The metal porous body 62 is preferably a metal of any type that is metallic, and may be a single metal of a single element or an alloy (including solid solution) of the single element. Specifically, the porous metal body 62 may be formed of a metal such as iron (Fe), nickel (Ni), aluminum (Al), titanium (Ti), copper The iron-based or nickel-based metal is at least one selected from the group consisting of pure metals, iron-chromium-based iron-nickel-based alloys, One can be the main component.

2 is a flowchart illustrating a conductive powder coating method using an electrostatic powder according to an embodiment of the present invention. Here, the coating apparatus of the present invention will be described with reference to FIG.

2, the conductive powder 32 is first introduced into the powder reservoir 30, and the porous metal body 62 is fixed to the support 60 (S10). Thereafter, negative (-) charge is supplied from the power supply source 40 to the charge unit 50 (S20). The blower 20 is operated to send the conductive powder 32 to the charging unit 50 through the transfer pipe 34 (S30). At this time, the conductive powder 32 transferred to the charge section 50 is charged with negative (-) charge. The conductive powder 52 charged with the negative charge is injected from the charge section 50 to the porous metal body 62 (S40). If desired, the metal porous body 62 fixed to the support table 60 can be moved left and right, front and rear, up and down, or rotated in the direction of the paper surface. As described above, by moving or rotating the porous metal body 62, it is possible to coat the large-area porous metal body 62 with the conductive powder 52.

Meanwhile, the thickness of the conductive coating layer coated with the conductive powder 52 on the porous metal body 62 can be controlled by repeating steps S 20 to S 40. (S30) of sending the conductive powder to the charge unit (S30) and injecting the conductive powder into the porous metal body (S40) repeatedly can do. As described above, by repeating steps S20 to S40, the thickness of the conductive coating layer coated on the porous metal body 62 can be freely adjusted.

Subsequently, the removed conductive powder 76 not attached to the porous metal article 62 is collected by the suction motor 72 through the suction port 74 and stored in the powder collecting tank 70 (S50). At this time, a filter such as a HEPA filter may be attached to the suction port 74 to remove the electroconductive powder 76 having a proper size. Subsequently, the metal porous body 62 coated with the conductive powder 52 is degreased and sintered by various heat treatment furnaces such as a vacuum furnace, a reducing furnace, and an atmosphere furnace to be stabilized (S60). If necessary, degreasing may be performed. The step of collecting the dropped conductive powder 76 (S50) may be applied after the step S40 is performed every time the steps S20 to S40 are repeated.

Hereinafter, the present invention will be described in more detail based on the following embodiments. The following examples are intended to illustrate but not limit the invention.

(Example 1)

In Example 1 of the present invention, an Fe powder having an average particle size of 45 占 퐉 (manufactured by Sekisui Chemical Co., Ltd.) was coated on a Ni porous body having a width of 200 mm × 300 mm and an average pore size of 1,200 μm to a thickness of 0.1 mm. Specifically, the charged Fe powder was injected at a spraying rate of 60 m < 2 > / hour to a Ni porous body at a distance of 30 cm at an applied voltage of 60 KV and a blowing gas pressure of 4 m & At this time, the Ni porous bodies were moved up and down and left and right at a speed of 5 cm / sec, and the injection time was 15 seconds. This process was repeated 5 times.

The unattached Fe powder was collected and stored in a powder collecting tank for reuse. Thereafter, the Ni porous body coated with the Fe powder was heated to 1,250 ° C at a rate of 10 ° C / min in a hydrogen atmosphere, and then sintered for 1 hour. The sintered porous body was cooled to finally obtain an Fe-Ni porous body (Fig. 3). At this time, FIG. 3 is a photograph cut by approximately 150 * 70 mm in width * for measurement.

FIG. 4A is a photograph of a Fe-Ni porous body produced by Embodiment 1 of the present invention magnified 60 times by a scanning microscope, FIG. 4B is a graph showing the composition of FIG. 4A by EDS (Energy Dispersive Spectroscopy) Graph.

4A and 4B, it was confirmed that the Fe powder having an average particle size of 45 μm was coated in a uniform size and shape. Further, the above-mentioned Ni porous body was coated with the Fe powder to a predetermined thickness.

(Example 2)

 In Example 2 of the present invention, FeCrAl powder (manufactured by Sandvik Osprey Co., Ltd., England) having an average particle diameter of 45 탆 was coated on a Ni porous body having a size of 200 * 300 mm in length × 200 mm and an average pore size of 1,200 탆 in a thickness of 0.1 mm . Specifically, the charged FeCrAl powder was sprayed onto the Ni porous body at a distance of 30 cm at an injection rate of 60 m 2 / hour at an applied voltage of 60 KV and a blowing gas pressure of 4 m 2 / hour. At this time, the Ni porous bodies were moved up and down and left and right at a speed of 5 cm / sec, and the injection time was 15 seconds. This process was repeated 5 times.

The unattached FeCrAl powder was collected and stored in a powder collector for reuse. Thereafter, the Ni porous body coated with the FeCrAl powder was heated to 1,250 ° C at a rate of 10 ° C / min in a hydrogen atmosphere, and then sintered for 1 hour. The sintered porous body was cooled to finally obtain a FeCrAl-Ni porous body similar to Fig.

FIG. 5A is a photograph of a FeCrAl-Ni porous body produced according to Example 2 of the present invention by a scanning electron microscope 100 times magnification, FIG. 5B is a photograph of the composition of FIG. 5A analyzed by an EDS (Energy Dispersive Spectroscopy) Graph.

5A and 5B, it was confirmed that the FeCrAl powder having an average particle size of 45 μm was coated in a uniform size and shape. Further, the FeCrAl powder was coated to a predetermined thickness on the used Ni porous body.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the spirit and scope of the invention. It is possible.

10; Chamber 20; air blower
30; Powder reservoir 32; Conductive powder
40; A power supply 50; Whole
52; A charged conductive powder 60; support fixture
62; A metal porous body 70; Powder collecting tank
72; Suction motor 74; Inlet
76; The dropped conductive powder

Claims (16)

A supporting base to which the porous metal body is fixed and charged with the first type of charge;
A charge portion for charging the conductive powder coated on the porous metal body with a charge of a second type opposite in polarity to the charge of the first type;
A power supply for supplying the charge of the second type to the charge portion; And
And a powder reservoir for storing said conductive powder for sending to said load,
The conductive powder charged in the charging part has electrical conductivity and is electrically neutralized when it comes in contact with the porous metal body. The conductive powder is attached to the porous metal body by its own charge, and has an average particle diameter of 1 탆 to 1,000 탆 , And a coating layer composed of the conductive powder formed on the porous metal body is repeatedly coated to adjust the thickness of the coating layer. The electroconductive powder coating apparatus using electrostatic powder according to claim 1, wherein the charge of the first form is a positive charge or a negative charge. The electroconductive powder coating apparatus using the electrostatic powder according to claim 1, wherein the conductive powder is any one of a corona charging system, an ion implanter, and a plasma ionizer. The electroconductive powder coating apparatus using electrostatic powder according to claim 1, wherein the support is movable in at least one of up and down, left and right, and back and forth, and is rotatable in a cylindrical shape. The electroconductive powder coating apparatus using electrostatic powder according to claim 1, wherein a voltage applied to the charge unit is 100V to 10,000KV. 2. The method according to claim 1, wherein the average particle diameter of the conductive powder is determined by a surface state of the porous metal body, an average weight (W) of the conductive powder, (D) between the charging portion and the porous metal body, and an injection flow rate (F) of the conductive powder. The electrostatic powder coating according to claim 1, wherein the conductive powder Device. delete The electroconductive powder coating apparatus according to claim 1, wherein the conductive powder is at least one selected from a single element selected from the group consisting of a conductive metal and a semiconductor, or an alloy thereof (including solid solution) . The method of claim 8, wherein the conductive powder is selected from the group consisting of carbon (C), silicon (Si), a conductive polymer, iron (Fe), chromium (Cr), nickel (Ni), cobalt (Co), platinum Wherein the conductive powder is at least one selected from a single element selected from the group consisting of gold (Au), gold (Au), silver (Ag) and barium (Ba) . The conductive powder coating apparatus using electrostatic powder according to claim 1, wherein the porous metal body is at least one selected from a single metal consisting of a single element or an alloy thereof (including solid solution). The metal porous body according to claim 10, wherein the porous metal body is one of Fe, Ni, Al, Ti, Cu, noble metal (Ag, Au, Pt, Pd) Wherein the electroconductive powder is at least one selected from the group consisting of silver, gold, silver, silver, silver, silver, and silver. Introducing the conductive powder into the powder reservoir and fixing the porous metal body to the supporting table charged with the first type of charge;
Supplying a charge of a second type opposite in polarity from the charge of the first type to the charge portion from a power source;
Sending the conductive powder stored in the powder reservoir to the lower portion; And
And injecting the conductive powder charged with the charge of the second form into the porous metal body at the charge portion,
The conductive powder charged in the charging part has electrical conductivity and is electrically neutralized when it comes in contact with the porous metal body. The conductive powder is attached to the porous metal body by its own charge, and has an average particle diameter of 1 탆 to 1,000 탆 And spraying the conductive porous powder on the porous metal body to control the thickness of the coating layer formed of the conductive powder formed on the porous metal body is repeated at least twice or more. 13. The conductive powder coating method according to claim 12, wherein the charge of the first form is a positive charge or a negative charge. 13. The conductive powder coating method of claim 12, wherein the conductive powder is one of a corona charging method, an ion implanter, and a plasma ionizer. 13. The method according to claim 12, characterized by repeatedly performing the step of supplying the charge of the second form to the charge portion, sending the conductive powder to the charge portion, and injecting the conductive powder into the porous metal body By weight of the conductive powder. The conductive powder coating method according to claim 12, further comprising collecting the dropped conductive powder not adhering to the porous metal body with a powder collecting tank.

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