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 that utilizes microwave torch plasma with a high peripheral density to efficiently plasma process powder. [Background technology]

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

[0003] For this reason, the inner walls of semiconductor equipment are coated with a material that is resistant to plasma, high temperatures, and chemical corrosion by plasma spraying.

[0004] One example of the plasma spray coating material is yttria powder. Yttria powder is a fine powder with a particle size of typically 15 to 25 μm, and this type of spray coating material must have high fluidity to form a dense and dense coating film during plasma spray coating.

[0005] It has been proven that the electrostatic properties of powder materials are one of the most important factors affecting the flowability of powders. Contact and movement between the analytical equipment container and the powder, or between the powder and the powder particles, can cause charge to form on the surface of powder particles. This process is called tribocharging, and occurs when electrons move from one surface to the other when different materials come into contact with each other. One material then becomes positively charged, while the other becomes negatively charged. Materials that generate static electricity through tribocharging have poorer flowability than materials that do not generate static electricity. Therefore, there is a need for powder processing equipment that can improve powder flowability.

[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 as shown in FIG.

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

[0009] That is, the reactor 75 is provided in a shape that vertically penetrates the waveguide 60, and a space for generating plasma is formed inside. In order for microwaves from the waveguide 60 to enter 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 functions to transmit 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 the powder is treated by plasma.

[0011] However, in the conventional plasma torch 70, the waveguide 110 is a dominant mode TE. 10 This results in an electric field distribution in which a strong electric field appears in the center of the reactor 75, as shown in Figure 1. 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 Figure 1, 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 imported entirely from Japan, and reducing the raw material consumption costs of plasma spray coating by domestically producing yttria powder is an immediate challenge that must be solved by those skilled in the relevant fields. 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 improve 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 that allows for increased powder throughput. [Means for solving the problem]

[0016] According to one embodiment of the present invention, a powder processing apparatus using microwave torch plasma with a high peripheral density includes: a microwave waveguide having a width of na (n is an integer equal to or greater than 2) where a 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 all of two or more peaks of the electric field distribution within the waveguide; an injection port for a plasma discharge gas injected on one side of the discharge tube; and an injection port for a powder to be processed injected on 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 specific 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 specific 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 the 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, causing the gas to flow in a swirling manner within the discharge tube.

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

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

[0022] In one embodiment, the powder injection unit includes two or more powder injection units, and the powder injection units may be injected toward the peaks of the respective electric fields.

[0023] In one 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 treatment apparatus using the plasma. [Effects of the Invention]

[0025] When a powder processing apparatus using microwave torch plasma with a high peripheral region density according to one embodiment of the present invention is used, it is possible to improve the surface uniformity and fluidity of the powder, and most of the powder can be smoothly flowed in the swirl direction and processed efficiently, which has the advantage of increasing the amount of powder processed. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a cross-sectional view showing the configuration of a conventional microwave plasma torch device. [Figure 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; [Figure 3] 1 is a diagram illustrating an exemplary state of a dominant waveguide. [Figure 4] 10 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. [Figure 5] 1 is a diagram showing modes of a dominant waveguide and a 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] 10 is a graph showing the results of measuring the fluidity and apparent density of yttria powder after plasma treatment using a powder treatment apparatus using microwave torch plasma with high edge 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 treatment using a powder treatment apparatus using microwave torch plasma with a high edge density according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[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 may be modified in various ways and may have various forms. Specific embodiments are illustrated in the drawings and described in detail herein. However, this is not intended to limit the present invention to the particular disclosed form, 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 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 these terms. These terms are used only to distinguish one component from another. For example, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component, without departing from the scope of the present invention.

[0029] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprise" or "have" and the like 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 possibility of 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 to have a meaning consistent with the meaning they have in the context of the relevant art, and should not be 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 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 equal to or greater than 2). This corresponds to the waveguide shown in FIG. 3, where the width is defined as a and the height is defined as b.

[0034] The dominant mode refers to the 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 is.

[0035] The term "mode" refers to the form in which energy of a specific frequency is concentrated in a structure. In the case of a resonator, the mode refers to the resonant frequency and its resonant form, and in the case of a waveguide or transmission line, it refers to the form in which electromagnetic waves of a specific frequency band travel. This is related to the phenomenon in which energy is concentrated at a specific 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 specific mode, the structure must be designed so that the desired frequency energy converges in 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 the rectangular waveguide, and n and m are the mode numbers.

[0039] For example, TE 20 In mode, TE 10 Compared to the mode, m and a increase by two times at the same time, so in the above equation, TE 10 Mode and 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 frequencies such as 915 GHz and 5.8 GHz. In other words, unlike the specific waveguide of the dominant mode, the waveguide 110 of the present invention can transmit a microwave frequency determined according to the change in width even if the width is increased.

[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 the plasma density in the peripheral region of 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 discharge tube in a dominant waveguide and the location of the discharge tube in a waveguide of the present invention.

[0043] In one embodiment, to expand the arc plasma jet emitted 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 greater than or equal to 2. 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 greater than or equal to 1.

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

[0045] The electric field distribution refers to the distribution of the E-field, and areas with the same electric field magnitude are expressed in the same color or in contour form. In the electric field distribution, the area with the greatest electric field strength is called a peak, and the area with the smallest field strength is called a null. Such nulls form lines by connecting nulls between adjacent peaks, and are called null lines. Null lines include longitudinal null lines formed along the length of the waveguide and width null lines formed in a direction perpendicular to the length of the waveguide. Here, the null line can refer to a line connecting nulls and a line passing through nulls between adjacent peaks.

[0046] 6 to 8 show the positions of the discharge tubes in the powder processing apparatus of the present invention, which utilizes microwave torch plasma with high peripheral density.

[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 longitudinal null line 11 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 (2n)λ / 2 electric field distribution 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. 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 within the discharge tube 120. As a result, the diameter of the discharge tube 120 can be increased, and multiple peaks with high electric field strength of the electric field distribution of the waveguide 110 are included within the discharge tube 120, so that a high-density microwave torch plasma can be formed in the peripheral region of the discharge tube 120.

[0048] Alternatively, in the electric field distribution of the waveguide 110 with an increased width as shown in Fig. 4, the discharge tube 120 of the arc plasma generator 120 is disposed so that the longitudinal null line 11 of the electric field distribution passes through the center of the discharge tube 120, and simultaneously 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 (2n)λ / 2 electric field distribution formed along the width direction of the waveguide 110 are included within the diameter of the discharge tube 120, i.e., the longitudinal null line 11 passing through the center of the discharge tube 120, and multiple 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, and more peaks can be positioned in the peripheral region of the discharge tube 120, thereby forming a microwave torch plasma with a higher density in the peripheral region of the discharge tube 120 than in the case of Fig. 5.

[0049] FIG. 8 shows the position of discharge tube 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 Figure 8, when the discharge tube 120 is installed over the (2n+1)λ / 2 electric field distribution, the center of the discharge tube 120 is installed so that it is 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 Figures 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 surrounding areas of the discharge tube 120, i.e., in the peripheral region of the discharge tube 120. Therefore, 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, the plasma discharge gas injector 130 for injecting the plasma discharge gas into the discharge tube 120 is provided on one side of the discharge tube 120, for example, on the top of the discharge tube 120, and injects the plasma discharge gas into the discharge tube 120. At this time, the plasma discharge gas injector 130 injects in the tangential direction of the discharge tube 120, so that the injected plasma discharge gas can flow in a vortex 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 inject in a tangential direction of the discharge tube 120, in the same direction as the plasma discharge gas, and flow in a swirl direction. The treated powder injector 140 may be disposed adjacent to a peak of an electric field contained within the diameter of the discharge tube 120, and inject toward the peak of the electric field. The lower side of the discharge tube 120 may be a direction in which high-density microwave torch plasma is emitted by the peak.

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

[0054] Meanwhile, a powder treatment apparatus using microwave torch plasma with a high peripheral region density according to an 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, along the central axis of the waveguide 110, 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 occurs at the center of the discharge tube 120, and powder supplied in the swirling direction of the plasma discharge gas may 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 plurality 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 discharge tube 120 through the plasma discharge gas injector 130, and the plasma discharge gas flows in a swirl pattern within the discharge tube 120, thereby discharging microwave torch plasma in the discharge direction of the discharge tube 120, for example, toward the bottom of the discharge tube 120.

[0058] At this time, powder is supplied into the discharge tube 120 through the powder injector 140 toward the peaks, and the powder flows in the swirl direction while coming into contact with 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. Processing powder using a powder processing apparatus using microwave torch plasma with high peripheral density according to an embodiment of the present invention can reduce the static electricity of the powder material and improve the fluidity of fine powder.

[0061] 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 fluidity and apparent density of yttria powder after plasma treatment using a powder treatment apparatus using microwave torch plasma with high edge density according to an embodiment of the present invention.

[0067] The FA (Flow-ability) shown in the graph in Figure 8 was measured in accordance with the National Standard No. KS L 1626, the method for evaluating the flowability of fine ceramic powders. It is the value measured by a standard measuring device, measuring 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 This powder processing apparatus has a discharge tube that passes vertically through a mode waveguide, a plasma discharge gas injection section on one side of the discharge tube, and a powder injection section on the other side of the discharge tube. In this control group apparatus, microwave torch plasma with a high density in the central region of the discharge tube is generated, and the plasma processing conditions for 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, a significant amount of static electricity was observed before plasma treatment. However, after plasma treatment, the amount of static electricity was significantly reduced. This is believed to be because the pores and rough edges on the surface of the yttria powder particles are filled or partially melted by the plasma treatment. As the pores on the surface of the powder particles are filled, the amount of mobile charge decreases, and as the rough edges are melted and become spherical, the charge on the powder particle surface decreases, reducing friction. This suggests that plasma treatment reduces the cohesion between powder particles and improves fluidity.

[0074] Also, as shown in Table 1, it can be seen 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 a high peripheral density according to an embodiment of the present invention.

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

[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 by smoothly flowing most of the powder 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 contained 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 powder throughput.

[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. Therefore, 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 penetrates the waveguide vertically so as to include all of two or more peaks of the electric field distribution within the waveguide; an injection part for injecting a plasma discharge gas into one side of the discharge tube; an injection portion for injecting the powder to be treated into the other side of the discharge tube; Including, the plasma discharge gas injection section is configured to inject the plasma discharge gas tangentially into the discharge tube, causing the gas to flow in a swirl pattern within the discharge tube; The powder to be treated is injected from the injection portion in the same direction as the direction of the swirling gas flow, The injection portion of the powder to be treated is injected toward the peak of the electric field, The powder processing apparatus using microwave torch plasma with high peripheral density further comprises an injection unit for injecting straight gas in a central axis direction of the waveguide at the one side of the waveguide.

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 n a (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 longitudinal null line of the electric field distribution passes through the center of the discharge tube and includes an adjacent peak of the electric field distribution when an electric field distribution formed along the 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 region 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. The injection portion for the powder to be treated includes two or more; 2. The powder processing apparatus using microwave torch plasma with high peripheral density according to claim 1, wherein the injection portion of the powder to be processed is injected toward the peak of each of the electric fields.

5. A plasma spray coating apparatus comprising the plasma-assisted powder processing apparatus according to any one of claims 1 to 4.

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