Powder processing equipment using microwave torch plasma with high edge density

Abstract

A powder processing apparatus using microwave torch plasma with high edge region density is disclosed. The powder processing apparatus using microwave torch plasma with high edge region density is characterized by including a microwave waveguide with a width of na (n is an integer of 2 or more) when the width of a dominant mode for transmitting electromagnetic waves of a specific frequency is a, a discharge tube that vertically penetrates the waveguide to include two or more peaks of the electric field distribution in the waveguide, an injection part for plasma discharge gas injected on one side of the discharge tube, and an injection part for powder to be processed injected on the other side of the discharge tube.

Description

[Technical field]

[0001] The present invention relates to a powder processing apparatus, and more particularly to a powder processing apparatus that utilizes a microwave torch plasma with a high peripheral area density to efficiently plasma process powder. [Background technology]

[0002] High density plasma processes are being used to manufacture highly integrated semiconductor devices with dimensions of several tens of nanometers or less, which requires semiconductor equipment to have durability against plasma radical corrosion and functionality in terms of cation resistance.

[0003] For this reason, materials that are resistant to plasma, high temperatures, and chemical corrosion are used for the inner walls of semiconductor equipment by plasma spray coating.

[0004] One example of the plasma spray coating material is yttria powder. Yttria powder is a fine powder having a particle size of 15 to 25 um, and such a spray coating material must have high fluidity in order to form a dense coating film with high density during plasma spray coating.

[0005] It has also been proven that the electrostatic properties of powder materials are one of the most important factors that affect the flowability of powders. Electric charges can be obtained on the surface of powder particles through contact and movement between the analytical equipment container and the powder, or between the powder and the inside of the powder particles; this process is called tribocharging, and this phenomenon occurs when different materials come into contact with each other, and electrons move from one surface to the other. At this time, one material becomes positively charged and the other negatively charged. Materials that generate static electricity through tribocharging have poorer flowability (fluidity) than materials that do not generate static electricity. Therefore, there is a need to develop powder processing equipment that can improve the fluidity of powders.

[0006] Meanwhile, a number of plasma-based powder processing apparatuses have been developed and utilized for powder processing.

[0007] As an example, the powder is treated using a microwave plasma torch apparatus such as that shown in FIG.

[0008] Referring to FIG. 1, the plasma torch 70 may be comprised of a reactor 75 that is formed to vertically penetrate the waveguide 60 , and a quartz 80 .

[0009] That is, the reactor 75 is provided in a form that vertically penetrates the waveguide 60, and a space for generating plasma is formed inside. Also, in order for the microwaves of the waveguide 60 to flow into the reactor 75, the portion where the waveguide 60 meets the reactor is opened, and quartz 80 is provided at that position. The quartz 80 performs the function of transmitting microwaves while blocking the inflow of gas, and the microwave transmission region and the plasma region are separated by the quartz 80.

[0010] When powder is to be treated, plasma gas, reactive gas and powder to be treated are introduced from the top of the reactor 75 in the direction of the arrows, and treatment with plasma is performed.

[0011] However, in the conventional plasma torch 70, the waveguide 110 is a dominant mode TE. 10 1, a strong electric field appears in the center of the reactor 75. When plasma is generated with such an electric field distribution, the density of the plasma becomes high only in the center.

[0012] Therefore, when processing powder using the conventional plasma torch 70 shown in FIG. 1, there is a problem in that the powder processing efficiency is high only in the center of the plasma, making it difficult to efficiently process all of the powder that is added.

[0013] Meanwhile, the yttria powder is currently entirely imported from Japan, and reducing the raw material consumption costs of plasma spray coating by domestically producing yttria powder is an immediate challenge to be solved by those skilled in the relevant field. Summary of the Invention [Problem to be solved by the invention]

[0014] Therefore, an object of the present invention is to provide a microwave torch plasma with a high density in the peripheral region, which can increase the surface uniformity and fluidity of the powder, and can efficiently process the powder while allowing most of the powder to smoothly flow in the swirl direction without adhering or accumulating on the inner wall of the discharge tube.

[0015] Another object is to provide a microwave torch plasma with a high edge density allowing increased powder throughput. [Means for solving the problem]

[0016] A powder processing apparatus using microwave torch plasma with high edge region density according to one embodiment of the present invention is characterized by comprising: a microwave waveguide having a width of na (n is an integer equal to or greater than 2) when the width of a dominant mode for transmitting electromagnetic waves of a specific frequency is a; a discharge tube vertically penetrating the waveguide so as to include two or more peaks of the electric field distribution within the waveguide; an injection portion for a plasma discharge gas injected to one side of the discharge tube; and an injection portion for powder to be processed injected to the other side of the discharge tube.

[0017] In one embodiment, when the width of a dominant mode for transmitting an electromagnetic wave of a particular frequency is a, the width of the waveguide is na (n is an integer of 2 or more), and when the electric field distribution along the width direction of the waveguide is (2n)λ / 2 (n is an integer of 1 or more), the discharge tube can be installed such that a longitudinal null line of the electric field distribution passes through the center of the discharge tube and includes adjacent peaks of the electric field distribution.

[0018] In one embodiment, when the width of a dominant mode for transmitting an electromagnetic wave of a particular frequency is a, the width of the waveguide is na (n is an integer of 2 or more), and when the electric field distribution along the width direction of the waveguide is (2n+1)λ / 2 (n is an integer of 1 or more), the center of the discharge pipe may be installed to be located at a middle peak in the width direction among the peaks in the length direction of the electric field distribution.

[0019] In one embodiment, the plasma gas injector may be configured to inject the plasma gas tangentially into the discharge tube, so that the gas flows in a swirling manner within the discharge tube.

[0020] In one embodiment, the powder injection section may inject in the same direction as the swirling gas direction.

[0021] In one embodiment, the powder injection may be directed towards the peak of the electric field.

[0022] In one embodiment, the powder injector may include two or more powder injectors, each of which may inject towards a peak of the electric field.

[0023] In an embodiment, the waveguide may further include an injection unit configured to inject straight gas in a central axis direction of the waveguide at the one side of the waveguide.

[0024] A plasma spray coating apparatus according to an embodiment of the present invention may include a powder processing apparatus using the plasma. Effect of the Invention

[0025] By using a powder processing apparatus using microwave torch plasma with high peripheral area density according to one embodiment of the present invention, it is possible to improve the surface uniformity and fluidity of the powder, and most of the powder can be efficiently processed while smoothly flowing in the swirl direction, which is advantageous in that the amount of powder processed can be increased. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a cross-sectional view showing the configuration of a conventional microwave plasma torch device. [Diagram 2] 1 is a cross-sectional view showing the configuration of a powder processing apparatus using microwave torch plasma with high edge density according to an embodiment of the present invention; [Diagram 3] 1 is a diagram illustrating an example state of a dominant waveguide. [Figure 4] 13 is a diagram showing the location of the ejector tube in a dominant waveguide and the location of the ejector tube in a waveguide of the present invention. [Diagram 5] 1 is a diagram showing modes of a dominant waveguide and the waveguide of the present invention. [Figure 6] 1 illustrates the position of a discharge tube in a powder processing apparatus using microwave torch plasma with high edge density according to an embodiment. [Figure 7] 1 illustrates the position of a discharge tube in a powder processing apparatus using microwave torch plasma with high edge density according to an embodiment. [Figure 8] 1 illustrates the position of a discharge tube in a powder processing apparatus using microwave torch plasma with high edge density according to an embodiment. [Figure 9] 1 is a graph showing the results of measuring the flowability and apparent density of yttria powder after plasma treatment using a powder treatment apparatus using microwave torch plasma with high edge region density according to an embodiment of the present invention. [Figure 10] 1 is a graph showing the cohesion of yttria powder before and after plasma processing using a powder processing apparatus using microwave torch plasma with high edge density according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, a powder processing apparatus using microwave torch plasma with high peripheral density according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The present invention can be modified in various ways and can have various forms. Specific embodiments are illustrated in the drawings and described in detail herein. However, it is not intended to limit the present invention to the specific disclosed forms, but it should be understood that the present invention includes all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Like reference numerals are used to refer to like elements throughout the various drawings. In the accompanying drawings, the dimensions of structures are exaggerated to clarify the present invention.

[0028] Terms such as "first" and "second" may be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another. For example, the first component may be named the second component, and the second component may be named the first component, without departing from the scope of the present invention.

[0029] The terms used in this application are merely used to describe certain embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, the terms "include" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0030] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and not interpreted in an idealized or overly formal sense unless expressly defined in this application.

[0031] FIG. 2 is a cross-sectional view showing the configuration of a powder processing apparatus using microwave torch plasma with high edge density according to one embodiment of the present invention, and FIG. 2 is a diagram showing an exemplary state of a dominant waveguide.

[0032] Referring to FIG. 2, a powder processing apparatus using microwave torch plasma with high peripheral area density according to one embodiment of the present invention may include a microwave waveguide 110, a discharge tube 120, a plasma discharge gas injection unit 130, and a powder to be processed injection unit 140.

[0033] The microwave waveguide 110 is a waveguide having a width larger than that of a dominant mode waveguide for transmitting an electromagnetic wave of a specific frequency. That is, when the width of the dominant mode waveguide is a, the waveguide 110 of the present invention has a width of na (n is an integer of 2 or more). This corresponds to the waveguide shown in FIG. 3, in which the width is defined as a and the height is defined as b.

[0034] The term "dominant mode" refers to a mode that propagates with the least degradation in a waveguide that can accommodate one or more radio wave modes. In other words, it is the mode that has the lowest cutoff frequency. When fabricating a rectangular waveguide, the dominant mode is the TE 10 It is.

[0035] The term "mode" refers to the form in which energy of a particular frequency is concentrated in a structure. In the case of a resonator, the mode refers to the resonant frequency and the form of resonance, and in the case of a waveguide or transmission line, the mode in which electromagnetic waves of a particular frequency band travel. This is related to the phenomenon in which energy is concentrated at a particular frequency due to structural characteristics. The important thing is that the mode is ultimately determined by the form of the structure, and in order to use a particular mode, the structure must be designed so that the desired frequency energy converges to that mode.

[0036] Meanwhile, the cutoff frequency of the waveguide 110 of the present invention may be as follows: Only electromagnetic waves with frequencies equal to or higher than the cutoff frequency can be transmitted through the waveguide.

[0037]

number

[0038] In this case, c is the speed of light, a and b are the width and height of a rectangular waveguide, and n and m are the mode numbers.

[0039] For example, T.E. 20 In mode, TE 10 Compared to the TE mode, m and a increase by a factor of two at the same time, so in the above formula, TE 10 Mode, TE 20 The cutoff frequency of the mode is the same. A is three times larger, TE 30Therefore, even if a is increased by an integer multiple, microwaves of 2.45 GHz are transmitted. This also applies to 915 GHz, 5.8 GHz, etc. In other words, unlike the specific waveguide of the dominant mode, the waveguide 110 of the present invention is capable of transmitting a microwave frequency determined according to the change in width even if the change is made to an increased width.

[0040] The discharge tube 120 penetrates the waveguide 110 vertically so as to include two or more peaks of the electric field distribution in the waveguide 110 .

[0041] Hereinafter, an embodiment for increasing plasma density in the peripheral region within the discharge tube 120 in the powder processing apparatus using microwave torch plasma with high peripheral region density according to the present invention will be described in detail.

[0042] FIG. 4 is a diagram showing the location of the ejector tube in a dominant waveguide and the location of the ejector tube in a waveguide of the present invention.

[0043] As an example, in order to expand the arc plasma jet discharged from the arc plasma generator 120, the width of the waveguide 110 of the present invention is increased to a'=na, which is n times the width a of the specific waveguide of the dominant mode, as shown in Fig. 4. In this case, n is an integer of 2 or more. As a result, the width becomes 2a, and the electric field distribution along the width direction of the waveguide 110 becomes (2n)λ / 2. Here, n is an integer of 1 or more.

[0044] 5 is a diagram showing the dominant waveguide and the modes of the waveguide of the present invention. In FIG. 5, the electric field distribution is shown as a contour line.

[0045] The electric field distribution indicates the distribution of the E-field, and the places having the same electric field magnitude are shown in the same color or in the form of contour lines. In the electric field distribution, the part where the electric field strength is the greatest is called a peak, and the part where the electric field strength is the smallest is called a null. Such nulls form lines by connecting the nulls between adjacent peaks, and are called null lines. The null lines include a lengthwise null line formed along the length of the waveguide and a widthwise null line formed along a direction perpendicular to the length of the waveguide. Here, the null line may include a line connecting nulls and a line passing through the nulls between adjacent peaks.

[0046] 6 to 8 show the positions of the discharge tubes in the powder processing apparatus utilizing microwave torch plasma with high edge density according to the present invention.

[0047] In the electric field distribution of the waveguide 110 with an increased width as shown in FIG. 4, the discharge tube 120 is disposed so that the null line 11 in the longitudinal direction of the electric field distribution passes through the center of the discharge tube 120 as shown in FIG. 6. In this case, adjacent peaks of the electric field distribution of (2n)λ / 2 formed along the width direction of the waveguide 110 are included within the diameter of the discharge tube 120, i.e., adjacent peaks adjacent to the null located at the center of the discharge tube 120 are included. Therefore, due to the adjacent peaks, multiple peaks with high electric field strength of the electric field distribution can be located in the peripheral region of the discharge tube 120 inside the discharge tube 120. As a result, the diameter of the discharge tube 120 can be expanded, and multiple peaks with high electric field strength of the electric field distribution of the waveguide 110 are included inside the discharge tube 120, so that microwave torch plasma with high density can be formed in the peripheral region of the discharge tube 120.

[0048] Alternatively, in the electric field distribution of the waveguide 110 with a larger width as shown in Fig. 4, the discharge tube 120 of the arc plasma generator 120 is disposed so that the lengthwise null line 11 of the electric field distribution passes through the center of the discharge tube 120, and at the same time, the vertical null line 12 of the electric field distribution passes through the center of the discharge tube 120, as shown in Fig. 7. In this case, adjacent peaks of the electric field distribution of (2n)λ / 2 formed along the width direction of the waveguide 110 are included within the diameter of the discharge tube 120, i.e., the lengthwise null line 11 passing through the center of the discharge tube 120, and a number of adjacent peaks adjacent to the vertical null line 12. As a result, the diameter of the discharge tube 120 can be made wider than in the case of Fig. 5, more peaks can be positioned in the peripheral region of the discharge tube 120, and a microwave torch plasma with a higher density can be formed in the peripheral region of the discharge tube 120 than in the case of Fig. 5.

[0049] FIG. 8 shows the arrangement positions of discharge tubes 120 when the width of waveguide 110 is na (n is an integer greater than or equal to 2) and the electric field distribution formed along the width direction of waveguide 110 is (2n+1)λ / 2 (n is an integer greater than or equal to 1).

[0050] As shown in Fig. 8, when the discharge tube 120 is installed over the (2n+1)λ / 2 of the electric field distribution, the center of the discharge tube 120 is installed so as to be located at the middle peak in the width direction among the peaks in the length direction of the electric field distribution. In this case, the peak located at the center of the discharge tube 120 and multiple peaks adjacent to it are included within the diameter of the discharge tube 120. As a result, the diameter of the discharge tube 120 can be made wider than in the cases of Figs. 6 and 7, and the peaks with high electric field strength of the electric field distribution of the waveguide 110 are included in the center and around the center of the discharge tube 120, i.e., in the peripheral region of the discharge tube 120, so that the density of the microwave torch plasma generated in the discharge tube 120 can be increased not only in the peripheral region of the discharge tube 120 but also in the central region.

[0051] In the arrangement structure of the discharge tube 120 according to this embodiment, a plasma discharge gas injection unit 130 for injecting a plasma discharge gas into the inside of the discharge tube 120 is provided on one side of the discharge tube 120, for example, on the upper part of the discharge tube 120, and injects a plasma discharge gas into the inside of the discharge tube 120. At this time, the plasma discharge gas injection unit 130 injects in the tangential direction of the discharge tube 120, and the injected plasma discharge gas can flow in a vortex shape (swirl shape) within the discharge tube 120.

[0052] The treated powder injector 140 is provided on the other side of the discharge tube 120, for example, on the lower side of the discharge tube 120, and injects powder into the other side of the discharge tube 120. At this time, the treated powder injector 140 may be injected in a tangential direction of the discharge tube 120, and may be injected in the same direction as the plasma discharge gas to flow in a swirl direction, and may be disposed adjacent to a peak of an electric field included within the diameter of the discharge tube 120 and may be injected toward the peak of the electric field. The lower side of the discharge tube 120 may be a direction in which microwave torch plasma with high density is discharged by the peak.

[0053] The number of the powder injection parts 140 to be processed may be two or more. In one embodiment, the number of the powder injection parts 140 may be the same as the number of peaks included within the diameter of the discharge tube 120. In this case, each powder injection part 140 to be processed may be disposed adjacent to each peak and may be injected toward each electric field peak.

[0054] Meanwhile, the powder treatment apparatus using microwave torch plasma with high peripheral area density according to one embodiment of the present invention may further include an injection unit 150 that injects straight gas from one side of the waveguide 110, i.e., the direction in which the plasma discharge gas injection unit 130 is located, toward the direction in which the powder to be treated injection unit 140 is located, in the direction of the central axis of the waveguide, i.e., along the central axis of the waveguide 110.

[0055] When the plasma discharge gas injected into the discharge tube 120 flows in a swirling manner, a reverse vortex may occur at the center of the discharge tube 120, causing the powder supplied in the swirling direction of the plasma discharge gas to adhere or accumulate toward the inner wall of the discharge tube 120. However, by injecting the straight gas, the reverse vortex can be prevented, thereby solving the problem.

[0056] Hereinafter, a process of processing powder using a powder processing apparatus using microwave torch plasma with high edge density according to an embodiment of the present invention will be described.

[0057] Electromagnetic waves are transmitted along the microwave waveguide 110, and a number of peaks are formed within the diameter of the discharge tube 120 due to the electric field distribution of the waveguide 110. A plasma discharge gas is injected into the inside of the discharge tube 120 through the plasma discharge gas injection unit 130, and the plasma discharge gas flows in a swirl shape within the discharge tube 120, and microwave torch plasma is discharged in the discharge direction of the discharge tube 120, for example, to the bottom of the discharge tube 120.

[0058] At this time, powder is supplied into the discharge tube 120 toward the peaks through the powder injector 140, and the powder flows in the swirl direction while contacting the microwave torch plasma.

[0059] During this process, the powder flows in a swirl direction along the inner periphery of the discharge tube 120, and comes into contact with the dense periphery of the microwave torch plasma.

[0060] The fluidity of powder is related to the electrostatic properties of the powder material. When powder is processed using a powder processing apparatus using microwave torch plasma with high peripheral density according to an embodiment of the present invention, the static electricity of the powder material can be reduced and the fluidity of the fine powder can be improved.

[0061] Working Example

[0062] Processing of Yttria Powder

[0063] 1) Flowability and apparent density of yttria powder before plasma treatment - Flow rate before processing (FA): 0g / sec -Untreated apparent density (TD): 0.98g / cc

[0064] 2) Plasma treatment conditions for yttria powder (present invention) -Plasma applied power: 8kW -Plasma discharge gas: Oxygen (25LPM) -Powder input amount: 119g / kWh -Yttria powder particle size distribution: 14±2um

[0065] 3) Measurement of flowability and apparent density of yttria powder after plasma treatment

[0066] FIG. 8 is a graph showing the results of measuring the flowability and apparent density of yttria powder after plasma treatment using a powder treatment apparatus using microwave torch plasma with high edge region density according to an embodiment of the present invention.

[0067] The FA (Flow-ability) shown in the graph of Figure 8 was measured according to the national standard number KS L 1626, the method for evaluating the flowability of fine ceramic powders, and is the value measured by a standard measuring device to determine the amount of powder flowing out per unit time, and the TD (Tap density) is the value measured by the mass per unit volume of the powder before and after processing.

[0068] As shown in FIG. 9, the apparent density of yttria before plasma treatment using the powder processing apparatus of the present invention was 0.98 g / cc, but after plasma treatment the apparent density of yttria increased to 2 g / cc. The fluidity of yttria before plasma treatment was 0 g / sec, but after plasma treatment the fluidity increased significantly to 8.62 g / sec.

[0069] 4) Measurement of tribocharging force of yttria powder after plasma treatment of the present invention and control group devices

[0070] Here, the control group device is TE 10 The control group device generates microwave torch plasma with a high density in the central region of the discharge tube, and the plasma treatment conditions for the yttria powder are as follows:

[0071] <Plasma treatment conditions for yttria powder in the control group device> -Plasma applied power: 8kW -Plasma discharge gas: Oxygen (25LPM) -Powder input amount: 119g / kWh -Yttria powder particle size distribution: 14±2um

[0072] [Table 1] <Comparison table of triboelectricity of yttria powder after plasma treatment using the present invention and a control group>

[0073] As shown in Table 1, it was measured that a considerable amount of static electricity was generated before plasma treatment. However, it was measured that the static electricity was relatively greatly reduced after plasma treatment. This is believed to be because the pores and rough corners formed on the surface of the yttria powder particles are filled or partially melted by the plasma treatment, and as the pores formed on the surface of the powder particles are filled, the mobile charge is reduced, and as the rough corners are melted and become spherical, the charge on the surface of the powder particles is reduced and the frictional force is also reduced. As a result, it is believed that the plasma treatment reduces the cohesion between powder particles and improves fluidity.

[0074] Also, as shown in Table 1, it can be confirmed that the static electricity of the powder is further reduced when the powder processing device of the present invention is used compared to the control group.

[0075] 5) Observation of the cohesion of yttria powder after plasma treatment

[0076] FIG. 10 is a graph showing the cohesion of yttria powder before and after plasma treatment using a powder treatment apparatus using microwave torch plasma with high peripheral density according to an embodiment of the present invention.

[0077] As shown in FIG. 10, it can be observed that the yttria powder before treatment is found to be solidified or aggregated, while the yttria powder after treatment is difficult to find to be solidified or aggregated.

[0078] By using the powder processing apparatus using microwave torch plasma with a high peripheral region density according to one embodiment of the present invention described above, the surface uniformity and fluidity of the powder can be improved, and the powder can be efficiently processed while flowing smoothly in the swirl direction without adhering or accumulating on the inner wall of the discharge tube 120.

[0079] In addition, since the waveguide 110 is a widened waveguide having an electric field distribution with multiple peaks, and the discharge tube 120 penetrates the waveguide 110 so that the multiple peaks are included within its diameter, the diameter of the discharge tube 120 can be increased, which has the advantage of further increasing the plasma density at the periphery of the discharge tube 120 and increasing the amount of powder that can be processed.

[0080] Meanwhile, the powder processing apparatus using microwave torch plasma with high peripheral density according to an embodiment of the present invention can be used in a plasma spray coating apparatus for plasma spray coating.

[0081] The description of the embodiments presented is provided to enable any person skilled in the art to use and practice the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments presented herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A microwave waveguide having a width of na (n is an integer of 2 or more) when the width of a dominant mode for transmitting an electromagnetic wave of a specific frequency is a; a discharge tube that perpendicularly penetrates the waveguide so as to include all of two or more peaks of the electric field distribution in the waveguide; an injection part for injecting a plasma discharge gas into one side of the discharge tube; an injection part for injecting the powder to be treated on the other side of the discharge tube; A powder processing apparatus utilizing a microwave torch plasma with high edge density.

2. 2. The powder processing apparatus using microwave torch plasma with high peripheral density according to claim 1, wherein the waveguide has a width of na (n is an integer of 2 or more) when a width of a dominant mode for transmitting an electromagnetic wave of a specific frequency is a, and the discharge tube is installed such that a null line in a length direction of an electric field distribution passes through a center of the discharge tube and includes an adjacent peak of the electric field distribution when an electric field distribution formed along a width direction of the waveguide is (2n)λ / 2 (n is an integer of 1 or more).

3. 2. The powder processing apparatus using microwave torch plasma with high peripheral density according to claim 1, wherein the width of the waveguide is na (n is an integer of 2 or more) when a width of a dominant mode for transmitting an electromagnetic wave of a specific frequency is a, and the center of the discharge pipe is installed to be located at a middle peak in a width direction among peaks in a length direction of the electric field distribution when an electric field distribution formed along a width direction of the waveguide is (2n+1)λ / 2 (n is an integer of 1 or more).

4. 2. The powder processing apparatus using microwave torch plasma with high peripheral density according to claim 1, wherein the plasma gas injection unit is configured to inject gas tangentially into the discharge tube so that the gas flows in a swirl pattern within the discharge tube.

5. 5. The apparatus of claim 4, wherein the powder injector injects the powder in the same direction as the swirl gas.

6. 6. The apparatus for processing powder using microwave torch plasma with high edge density as set forth in claim 5, wherein the powder injector injects the powder toward the peak of the electric field.

7. The powder injection section includes two or more 7. The apparatus for processing powder using microwave torch plasma with high edge density as set forth in claim 6, wherein the powder injecting unit injects the powder toward the peak of each of the electric fields.

8. 7. The apparatus of claim 6, further comprising an injection unit for injecting a straight gas in a central axis direction of the waveguide at the one side of the waveguide.

9. A plasma spray coating apparatus comprising the plasma-utilizing powder processing apparatus according to any one of claims 1 to 7.

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