WO2023096021A1 - Vacuum microwave spray coating device, method therefor and coating layer formed thereby - Google Patents

Abstract

Embodiments of the present invention relate to a vacuum microwave spray coating device, a method therefor and a coating layer formed thereby, and, in order to solve the described problem, provided are a vacuum microwave spray coating device, a method therefor and a coating layer formed thereby, the device changing aerosolized powder into a semi-molten powder by heating same with microwaves in a vacuum state, and making the aerosolized semi-molten powder collide with a substrate so as to pulverize same, thereby enabling a coating layer to be rapidly formed even if same is formed by aerosol deposition. To this end, disclosed are a vacuum microwave spray coating device, a method therefor and a coating layer formed thereby, the device comprising: a carrier gas supply part for supplying carrier gas; a powder supply part for aerosolizing and supplying a powder by means of the carrier gas; a microwave supply part, which supplies thermal energy to the powder through microwaves so as to semi-melt the powder; and a coating nozzle, which sprays the aerosolized semi-molten powder at a substrate so as to form a coating layer on the substrate, wherein the substrate, the microwave supply part and the coating nozzle are accommodated inside a vacuum chamber.

Description

Vacuum microwave spray coating device, method and coating layer according thereto

An embodiment of the present invention relates to a vacuum microwave spray coating apparatus, a method thereof, and a coating layer according thereto.

As a method of forming a structure containing a brittle material and/or a ductile material on the surface of a substrate, for example, an aerosol deposition method or a gas deposition method is known. In the aerosol deposition method or gas deposition method, an aerosol in which powder (fine particles) containing a brittle material and/or a ductile material is dispersed in a gas is sprayed from a discharge port toward a substrate, and the powder is deposited on a substrate such as metal, glass, ceramics, or plastic. collide with The impact of this collision causes the powder to be deformed or crushed so that they can be bonded, and a coating layer (film-like structure) containing the constituent material of the powder can be directly formed on the substrate.

The above-described information disclosed in the background art of the present invention is only for improving the understanding of the background of the present invention, and thus may include information that does not constitute prior art.

The problem to be solved according to the embodiment of the present invention is to heat the aerosolized powder with a microwave in a vacuum state to become a semi-melted powder, and collide and crush the aerosolized semi-melted powder on a substrate to form an aerosolized coating layer. It is to provide a vacuum microwave spray coating device that can be formed at a higher speed while forming by a deposition method, a method thereof, and a coating layer according to the method.

To this end, the vacuum microwave spray coating apparatus according to an embodiment of the present invention includes a transfer gas supply unit for supplying a transfer gas; a powder supply unit for aerosolizing and supplying powder by means of the transfer gas; a microwave supply unit supplying heat energy by microwave to the powder so that the powder is semi-melted; and a coating nozzle spraying the aerosolized semi-molten powder onto a substrate to form a coating layer on the substrate, and the substrate, the microwave supply unit, and the coating nozzle may be accommodated in a vacuum chamber. there is.

In some examples, the microwave supply may include a power supply; A microwave generator connected to the power supply to generate microwaves; a microwave amplifier connected to the microwave generator to amplify microwaves; an antenna connected to the microwave amplifier to radiate microwaves; and a waveguide connected to the antenna and guiding the microwave, and the coating nozzle may be penetrated through the waveguide.

In some examples, the coating nozzle may be coupled to the waveguide such that the longitudinal direction of the coating nozzle forms a right angle with respect to the longitudinal direction of the waveguide.

In some examples, the antenna and the waveguide may be provided inside the vacuum chamber.

In some examples, the antenna may be provided outside the vacuum chamber, the waveguide may be provided inside the vacuum chamber, and the antenna and the waveguide may be connected by an RF coaxial cable.

In some examples, the microwave amplifier may be a magnetron generating microwaves by oscillation or a semiconductor transistor by RF amplification of a transistor.

In some examples, an embodiment of the present invention may include a microwave power sensor for sensing power of microwaves reflected from the waveguide; a flow sensor for sensing the flow rate of the powder; and selecting a microwave frequency at which the reflection is the smallest using the microwave power sensor, and selecting a microwave power at which the powder is semi-melted using the flow sensor to determine the frequency of the microwave generator and the microwave power. A controller for controlling the output power of the microwave amplifier may be further included.

A vacuum microwave spray coating method according to an embodiment of the present invention includes a transfer gas supply step of supplying a transfer gas; a powder supply step of aerosolizing and supplying powder by the transport gas; a microwave supplying step of supplying heat energy by microwaves to the powder so that the powder is semi-melted; and a coating step of spraying the aerosolized semi-molten powder onto a substrate to form a coating layer on the substrate, and the substrate, a microwave supply unit, and a coating nozzle may be accommodated inside the vacuum chamber.

The coating layer according to the vacuum microwave spray coating method described above includes, as powder, yttria (Y2O3) having a particle size distribution D50 of 3 μm to 4 μm and zirconia (ZrO2) having a particle size distribution D50 of 2 μm to 3 μm, The wt % of yttria and zirconia may be from 85 to 15 to 35 to 65.

In some examples, the thickness of the coating layer may be 100 μm to 110 μm, and the hardness of the coating layer may be 5 GPa to 7 GPa.

In an embodiment of the present invention, the aerosolized powder is heated with a microwave in a vacuum state to become a semi-melted powder, and the aerosol semi-melted powder is collided with and crushed to a substrate to form a coating layer by an aerosol deposition method and at a higher speed. Provides a vacuum microwave spray coating device that can be formed, a method thereof, and a coating layer according to the method.

That is, in the embodiment of the present invention, the aerosolized powder is semi-melted or reacted at a temperature lower than the melting point of the powder using thermal energy by microwave to collide and crush the substrate, thereby reducing the conventional vacuum aerosol deposition at room temperature. A vacuum microwave spray coating device capable of forming a coating layer at a much faster film formation speed than the film formation speed by the method, a method thereof, and a coating layer according to the method are provided.

In addition, an embodiment of the present invention provides a coating layer of high hardness by mixing yttria and zirconia in an appropriate weight ratio and spraying them onto a substrate.

1A and 1B are configuration diagrams and flowcharts schematically showing a vacuum microwave spray coating apparatus, method, and coating layer according to an embodiment of the present invention.

Figure 2 is a configuration diagram schematically showing a vacuum microwave spray coating apparatus according to an embodiment of the present invention.

3 is a configuration diagram schematically showing a microwave supply unit in a vacuum microwave spray coating apparatus according to an embodiment of the present invention.

4 is a block diagram showing a microwave supply unit in a vacuum microwave spray coating apparatus according to an embodiment of the present invention.

5 is a circuit diagram schematically showing an example of a solid state power amplification unit of a microwave supply unit in a vacuum microwave spray coating apparatus according to an embodiment of the present invention.

6 is a diagram showing an example of an antenna of a microwave supply unit in a vacuum microwave spray coating apparatus according to various embodiments of the present invention.

7 is a graph showing the reflection input coefficient (|S11|) of an antenna in a vacuum microwave spray coating apparatus according to an embodiment of the present invention.

8 is an enlarged SEM (Scanning Electron Microscope) image of the powder according to an embodiment of the present invention.

9 is a photograph showing a coating layer according to an embodiment of the present invention.

10 is a diagram illustrating EDS (Energy Dispersive X-ray Spectroscopy) data of a coating layer (yttria:zirconia=85:15) according to an embodiment of the present invention.

11 is a diagram illustrating EDS (Energy Dispersive X-ray Spectroscopy) data of a coating layer (yttria:zirconia = 75:25) according to an embodiment of the present invention.

12 is a diagram illustrating EDS (Energy Dispersive X-ray Spectroscopy) data of a coating layer (yttria:zirconia=65:35) according to an embodiment of the present invention.

13 is a diagram showing thickness data of a coating layer according to an embodiment of the present invention.

14 is a graph showing an optimal hardness-thickness relationship according to an embodiment of the present invention.

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

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified in many different forms, and the scope of the present invention is as follows It is not limited to the examples. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the spirit of the invention to those skilled in the art.

In addition, in the following drawings, the thickness or size of each layer is exaggerated for convenience and clarity of explanation, and the same reference numerals refer to the same elements in the drawings. As used herein, the term "and/or" includes any one and all combinations of one or more of the listed items. In addition, the meaning of "connected" in the present specification means not only when member A and member B are directly connected, but also when member A and member B are indirectly connected by interposing member C between member A and member B. do.

Terms used in this specification are used to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular form may include the plural form unless the context clearly indicates otherwise. Also, when used herein, “comprise, include” and/or “comprising, including” refers to a referenced form, number, step, operation, member, element, and/or group thereof. presence, but does not preclude the presence or addition of one or more other shapes, numbers, operations, elements, elements and/or groups.

In this specification, terms such as first and second are used to describe various members, components, regions, layers and/or portions, but these members, components, regions, layers and/or portions are limited by these terms. It is self-evident that These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described in detail below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

Space-related terms such as “beneath,” “below,” “lower,” “above,” and “upper” are associated with an element or feature shown in a drawing. It can be used for easy understanding of other elements or features. Terminology related to this space is for easy understanding of the present invention according to various process conditions or use conditions of the present invention, and is not intended to limit the present invention. For example, if an element or feature in a figure is turned over, an element or feature described as "lower" or "below" becomes "above" or "above." Accordingly, "lower" is a concept encompassing "upper" or "below".

In addition, the control unit (controller) and/or other related devices or components according to the present invention may be implemented using any suitable hardware, firmware (eg, application specific semiconductor), software, or a suitable combination of software, firmware, and hardware. can For example, various components of a control unit (controller) and/or other related devices or parts according to the present invention may be formed on one integrated circuit chip or on separate integrated circuit chips. In addition, various components of the control unit (controller) may be implemented on a flexible printed circuit film, and may be formed on a tape carrier package, a printed circuit board, or the same substrate as the control unit (controller). In addition, various components of the control unit (controller) may be processes or threads executed in one or more processors in one or more computing devices, which execute computer program instructions to perform various functions mentioned below. and can interact with other components. Computer program instructions are stored in memory that can be executed in a computing device using standard memory devices, such as, for example, random access memory. Computer program instructions may also be stored on other non-transitory computer readable media, such as, for example, a CD-ROM, flash drive, or the like. In addition, those skilled in the art related to the present invention will understand that the functions of various computing devices can be combined with each other, integrated into one computing device, or the functions of a particular computing device can be incorporated into one or more other computing devices without departing from the exemplary embodiments of the present invention. It should be recognized that it can be dispersed in the field.

For example, the control unit (controller) according to the present invention is a central processing unit, a mass storage device such as a hard disk or a solid-state disk, a volatile memory device, an input device such as a keyboard or mouse, and an output device such as a monitor or printer. of commercial computers.

1A and 1B are configuration diagrams and flowcharts schematically showing a vacuum microwave spray coating apparatus, method, and coating layer according to an embodiment of the present invention.

As shown in FIG. 1A, the vacuum microwave spray coating apparatus 200 according to an embodiment of the present invention includes a transport gas supply unit 210, a powder supply unit 220 for storing and supplying powder, a powder supply unit ( A transfer pipe 222 for transferring powder from 220) at high speed using a transfer gas, a nozzle 232 for coating/laminating or spraying powder from the transfer tube 222 on a substrate 231, and a nozzle 232 The microwave supply unit 100 provides heat energy by microwaves to the powder passing through to make the powder into a semi-melted or semi-solid state, the semi-melted powder from the nozzle 232 collides with the surface of the substrate 231, It includes a process chamber 230 to form a coating layer having a certain thickness by crushing and/or pulverizing.

The formation method will be described with reference to FIGS. 1A and 1B together.

The transfer gas stored in the transfer gas supply unit 210 may be one or a mixture of two types selected from the group consisting of air, oxygen, helium, nitrogen, argon, carbon dioxide, hydrogen, and equivalents thereof, but the type of transfer gas is limited. It doesn't work. The transfer gas is directly supplied from the transfer gas supply unit 210 to the powder supply unit 220 through the pipe 211, and the flow rate and pressure can be controlled by the flow controller 250 (including a flow sensor therein). . The flow controller 250 (including the flow sensor) may transmit flow rate information of the powder to the microwave supply unit 100 .

The powder supply unit 220 stores and supplies a large amount of powder, and the powder may have a particle diameter ranging from about 0.1 μm to about 50 μm. When the particle size range of the powder is smaller than about 0.1 μm, it is difficult to store and supply the powder, and particles smaller than 0.1 μm when spraying, colliding, crushing, and/or grinding the powder due to aggregation during storage and supply of the powder There is a disadvantage in that it is easy to form a green compact, which is a form of agglomeration, and it is difficult to form a large area. In addition, when the particle size range of the powder is greater than about 50 μm, sand blasting, which cuts off the substrate during powder spraying, crushing, and/or crushing, is likely to occur, and the particle size of the partially formed coating layer is Since it is formed relatively large, the structure becomes unstable and the internal or surface porosity increases, so that the original characteristics of the material may not be exhibited.

When the particle size range of the powder is approximately 0.1 μm to 50 μm, a coating layer having a relatively small porosity (porosity), no surface micro-cracks, and a complex particle size that is easy to control the powder can be obtained. In addition, when the particle size range of the powder is approximately 0.1 μm to 50 μm, a coating layer having a relatively high lamination speed, translucent, and easy material properties can be obtained. Such powders may be brittle materials or/and ductile materials. Brittle materials are materials that are brittle and do not stretch, and include ceramics and glass. In addition, a ductile material means a material that stretches well, as opposed to a brittle material, such as copper and lead.

Specifically, the brittle material powder is yttria (Y2O3), YAG (Y3Al5O12), rare earth series (element series with atomic numbers 57 to 71 including Y and Sc) oxides, alumina (Al2O3), bio glass, silicon (SiO2) ), hydroxyapatite (hydroxyapatite), titanium dioxide (TiO 2 ), and may be one or a mixture of two selected from the group consisting of equivalents thereof, but the present invention is not limited to these materials.

More specifically, the brittle material or ductile material powder is hydroxyapatite, calcium phosphate, bio glass, Pb(Zr,Ti)O3 (PZT), alumina, titanium dioxide, zirconia (ZrO2), yttria (Y2O3), yttria- Zirconia (YSZ, Yttria stabilized Zirconia), dysprocia (Dy2O3), gadolinia (Gd2O3), ceria (CeO2), Gadolinia-doped Ceria (GDC), magnesia (MgO), barium titanate (BaTiO3) ), nickel manganate (NiMn2O4), potassium sodium niobate (KNaNbO3), bismuth potassium titanate (BiKTiO3), bismuth sodium titanate (BiNaTiO3), CoFe2O4, NiFe2O4, BaFe2O4, NiZnFe2O4, ZnFe2O4, MnxCo3-xO4 (where x is a positive real number of less than 3), bismuth ferrite (BiFeO3), bismuth zinc niobate (Bi1.5Zn1Nb1.5O7), lithium aluminum phosphate titanium glass ceramic, Li-La-Zr-O-based Garnet oxide, Li-La-Ti -O-based Perovskite oxide, La-Ni-O-based oxide, lithium iron phosphate, lithium-cobalt oxide, Li-Mn-O-based Spinel oxide (lithium manganese oxide), lithium aluminum gallium phosphate, tungsten oxide, tin oxide, nickel Scattered lanthanum, lanthanum-strontium-manganese oxide, lanthanum-strontium-iron-cobalt oxide, silicate phosphor, SiAlON phosphor, aluminum nitride, silicon nitride, titanium nitride, AlON, silicon carbide, titanium carbide, tungsten carbide, magnesium boride, boride A mixture of one or two selected from the group consisting of titanium, a mixture of metal oxide and metal nitride, a mixture of metal oxide and metal carbide, a mixture of ceramic and polymer, a mixture of ceramic and metal, nickel, copper, silicon and equivalents thereof However, the present invention is not limited to these materials.

The microwave supply unit 100 applies heat energy by microwaves (eg, 400 MHz to 40 GHz, specifically 433 MHz, 915 MHz or 2,450 MHz) to the powder passing through the nozzle 232 so that the powder is in a semi-molten state. make it become To this end, the microwave supply unit 100 may include a power supply unit 110, a microwave generator 120 (or RF generator), and a waveguide 191. Here, the microwave generator 120 and the waveguide 191 are located inside the vacuum chamber 230, and the nozzle 232 may be installed through the waveguide 191. The configuration and operation of the microwave supply unit 100 will be described in more detail below.

On the other hand, the semi-melted or semi-solid state of the powder means a state in which the powder is heated to a state lower than the melting point of the powder. For example, since the melting point of the alumina powder is approximately 2.072°C, the semi-melted or semi-solid state of the alumina powder means a state in which the alumina powder is heated to a temperature lower than approximately 2.072°C.

Powder heating using microwaves is a heating method that is essentially different from general heating methods, and has many advantages compared to general heating methods. It is particularly effective for heating powders with poor thermal conductivity, and has the following characteristics.

(1) Rapid heating: Microwaves instantly penetrate into the powder and generate heat, so the time required for heat conduction is unnecessary, so it can be heated in a shorter time compared to external heating methods by heat conduction.

(2) Uniform heating: In the external heating method, the temperature gradient inside and outside the powder cannot be avoided, and it takes time to heat uniformly. However, in microwave heating, if the electric force lines in the powder are to be generated uniformly, the temperature rise is also constant. In the external heating method, the temperature on the outside of the powder is high and the temperature on the inside of the powder is low, but in microwave heating, the amount of heat generated inside and outside the powder can be equal.

(3) Local heating: In many cases, it is difficult to heat only a local area in the method of externally heating the powder. In microwave heating, if the lines of electric force are concentrated on the part to be heated, it can be heated in a narrow range. Since the heating time is short, the area of the heating part is small.

(4) Selective heating: Since it is heat generated by dielectric loss, it is selectively absorbed by those with high dielectric loss, and only necessary parts can be heated. Since different materials have different microwave absorption properties, selective heating of the individual components that make up the powder is possible.

(5) High thermal efficiency: Since the powder itself becomes a heating element, there is no loss of heating the surrounding air or nozzles, so high thermal efficiency can be obtained.

(6) High-speed thermal response: Since microwaves have a high-speed response that propagates at the speed of light, temperature control by instantaneous start-up and stop and output control can be easily performed.

(7) Uniform heating regardless of shape: Because each part of the powder generates heat at the same time, it can be heated relatively uniformly even in a complicated shape.

(8) Suitability for industrial use: It is easy to automate and save power, requires a small installation area, and is simple to control and use, making it suitable for industrial heating devices.

(9) Thermal efficiency: Since microwaves are only absorbed by the powder passing through the nozzle and do not heat the surrounding nozzle wall and conveying gas, the thermal efficiency is naturally high. Therefore, it can be said to be quite useful for improving the working environment. In addition, since the energy can be concentrated on the required part, the thermal efficiency is high.

(10) Easy control: There is no direct contact between the heating source and the heating powder, and it has the advantage of being easy to control during the heating or drying process.

The process chamber 230 maintains a vacuum state during formation of the coating layer, and a vacuum unit 240 may be connected thereto. More specifically, the pressure of the process chamber 230 may be approximately 1 Pascal to 800 Pascals, and the pressure of the powder transported by the high-speed transfer pipe 222 may be approximately 500 Pascals to 2000 Pascals. However, in any case, the pressure of the high-speed transfer pipe 222 should be higher than the pressure of the process chamber 230 .

In addition, the internal temperature range of the process chamber 230 is approximately 0 °C to 30 °C, and therefore, a member for separately increasing or decreasing the internal temperature of the process chamber 230 may not be required. That is, the transfer gas and/or the substrate may be maintained at a temperature of 0° C. to 30° C. without being separately heated.

However, as described above, in order to improve the deposition efficiency and density of the coating layer, the powder may be heated to a temperature of about 30° C. to about 2000° C. by microwave. That is, when the coating layer is formed by heating the powder, the stress applied to the powder is reduced, and a small porosity and dense coating layer can be obtained.

Here, when the temperature of the powder is higher than about 2000 ° C., the powder melts and causes a rapid phase transition, and thus the porosity of the coating layer increases and the internal structure may become unstable. Also, when the powder is less than a temperature of approximately 30° C., the stress applied to the powder may not be reduced.

The temperature range is not limited in the present invention, and the temperature range of the transport gas, the substrate, the process chamber and/or the powder may be freely adjusted between about 0 °C and about 2000 °C according to the characteristics of the substrate on which the coating layer is to be formed.

Subsequently, as described above, the pressure difference between the process chamber 230 and the high-speed transfer pipe 222 (or the transfer gas supply unit 210 or the powder supply unit 220) may be approximately 1.5 times to 2000 times. When the pressure difference is less than about 1.5 times, high-speed transfer of the powder may be difficult, and when the pressure difference is greater than about 2000 times, the surface of the substrate may be excessively etched by the powder.

According to the pressure difference between the process chamber 230 and the transfer pipe 222, the powder from the powder supply unit 220 is injected through the transfer tube 222 and delivered to the process chamber 230 at high speed.

In addition, some structures of the nozzle 232 and the microwave supply unit 100 connected to the transfer pipe 222 are provided in the process chamber 230, and the semi-molten powder is supplied at a speed of about 50 m/s to about 500 m/s. It collides with the substrate 231. That is, the powder through the nozzle 232 is crushed and/or pulverized by kinetic energy obtained during transport, thermal energy obtained from microwaves, and collision energy generated during high-speed collision to form a certain thickness on the surface of the substrate 231. to form a coating layer.

Figure 2 is a configuration diagram schematically showing a vacuum microwave spray coating apparatus (200A) according to an embodiment of the present invention.

Here, the configuration of the microwave supply unit 100A is different from the configuration of the microwave supply unit 100 described above. That is, in FIG. 1A, among the microwave supply unit 100, the waveguide 191 to which the microwave generator 120 and the nozzle 232 are coupled is located inside the vacuum process chamber 230, and the power supply unit 110 ) was located outside the process chamber 230.

However, as shown in FIG. 2 , only the waveguide 191 to which the nozzle 232 is coupled may be located inside the vacuum process chamber 230 . Also, the power supply 110 and the microwave generator 120 may be located outside the process chamber 230 . Accordingly, the waveguide 191 may be connected to the microwave generator 120 through a flexible RF coaxial cable 192 . Therefore, the waveguide 191 and the nozzle 232 can freely move in 2D and/or 3D inside the vacuum chamber 230, thereby forming a coating layer on the 2D and/or 3D substrate 231. can be formed easily.

Figure 3 is a configuration diagram schematically showing the microwave supply unit 100 of the vacuum microwave spray coating apparatus according to an embodiment of the present invention. 4 is a block diagram showing a microwave supply unit 100 in a vacuum microwave spray coating apparatus according to an embodiment of the present invention.

3 and 4, in the vacuum microwave spray coating apparatus according to an embodiment of the present invention, the microwave supply unit 100 includes a power supply unit 110, a microwave generator 120, and a microwave It may include a power amplifier 140, an antenna 160, and a controller 170.

In addition, in the vacuum microwave spray coating apparatus according to an embodiment of the present invention, the microwave supply unit 100 includes a signal attenuator 130, an isolator 150, a microwave power sensor 181, and a powder flow sensor 182. ), the antenna 160 and the nozzle 232 are combined and may further include a waveguide 191 located inside the vacuum chamber 230.

Here, the nozzle 232 is coupled to the waveguide 191, which means that the longitudinal direction of the nozzle 232 is substantially orthogonal to the longitudinal direction of the waveguide 191, so that energy by microwaves is easily applied to the powder. to be absorbed.

The power supply 110 serves to supply DC power to the microwave generator 120 and the microwave power amplifier 140. The power supply 110 may be, for example, but not limited to, a Switching Mode Power Supply (SMPS). In addition, the power supply 110 may use a normal commercial AC voltage (eg, AC 110 to 220V).

The microwave generator 120 serves to generate microwaves by receiving DC power from the power supply 110 and transmits them to the signal attenuator 130 or the microwave power amplifier 140 . The microwave generator 120 may generate, for example, but not limited to, microwaves having a frequency of approximately 400 to 2500 MHz, and this frequency band may be easily changed through software. Here, in an embodiment of the present invention, microwaves of 433 MHz or 2450 MHz can be generated through the microwave generator 120, for example.

The signal attenuator 130 is connected to the front end of the microwave power amplification unit 140, and serves to attenuate a microwave signal greater than the input allowed by the microwave power amplifier 140, if present. That is, a stable amplification operation is implemented without oscillation occurring in the microwave power amplifier 140 by the signal attenuator 130 .

The microwave power amplifier 140 serves to receive microwaves from the microwave generator 120, amplify them, and output them to the antenna 160. The microwave power amplification unit 140 may output, for example, but not limited to, microwaves having a power of approximately 400 to 10000 watts, and this power may also be easily changed through software.

In addition, the microwave power amplifier 140 may be, for example, but not limited to, a magnetron generating microwaves by oscillation or a semiconductor transistor by RF amplification of a transistor.

In particular, the amplifier 140 may include, for example, but not limited to, a Laterally Diffused Metal Oxide Semiconductor Field Effect Transistor (LDMOS transistor), a GaN transistor, a GaAs transistor, an InP transistor, or a TWT/TWTa transistor. . This type of microwave power amplification unit 140 may output, for example, but not limited to, microwaves of 200 MHz to 100 GHz and 0.5 to 10000 watts.

The isolator 150 is interposed between the microwave power amplification unit 140 and the antenna 160, so that impedance matching is strengthened so that power or power transmission is more smooth. In particular, microwave power amplification from the antenna 160 It serves to prevent the reverse signal from flowing into the unit 140. Of course, it is natural that the microwave power sensor 180 to be described below is connected between the isolator 150 and the antenna 160 due to the isolator 150.

The antenna 160 receives microwaves from the microwave power amplifier 140 and directs them to the aerosolized powder in the waveguide 191 to which the nozzle 232 is coupled, serving to heat the powder. . At least one of these antennas 160 may be installed on the inner surface of the waveguide 191.

The aforementioned antenna 160 may be, for example, but not limited to, one or more selected from ceramic patch antennas, dipole antennas, monopole antennas, helical antennas, and equivalents thereof.

The controller 170 controls the microwave generator 120 and/or the microwave power amplifier 140 to control the frequency and/or output power of the microwave. Since the configuration of the controller 170 has already been described above, a detailed description thereof will be omitted.

The microwave power sensor 181 serves to sense the microwave power reflected from the heating target, that is, the powder, and provide it to the controller 170. As described above, the microwave power sensor 181 is installed between the isolator 150 and the antenna 160, and transmits the microwave power reflected from the powder and received through the antenna 160 to the controller 170. In addition, the flow sensor 182 senses the flow rate of the aerosolized powder passing through the nozzle 232 and transmits it to the controller 180 . Here, the flow sensor 182 may be installed inside the flow controller 250 as an example.

Then, as described above, the controller 170 determines the frequency of the lowest microwave among the frequencies of the microwave reflected from the microwave power sensor 181 as the frequency of the output microwave, so that the microwave with maximum efficiency is applied to the powder. to be sent In addition, the controller 170 determines the power of the microwave based on the flow rate of the powder obtained from the flow sensor 182, so that the powder is heated and semi-melted at a preset temperature at any flow rate.

In this way, among the vacuum microwave spray coating apparatus according to the embodiment of the present invention, the microwave supply unit 100 is capable of local heating rather than simple heating by uniform heat transfer through the antenna 192, and various applications of semiconductor technology are possible. It can be expanded with functions, it can be designed with a light and compact design with a simple configuration, and it is also possible to have sophisticated control. The core of the powder can be rapidly heated by using the frequency band. In particular, among the vacuum microwave spray coating apparatus according to the embodiment of the present invention, the microwave supply unit 100 can rapidly heat by using a low frequency, and can reduce a spark phenomenon with metal by using a low frequency.

5 is an equivalent circuit diagram showing an example of the microwave power amplifier 140 of the microwave supply unit 100 among the vacuum microwave spray coating apparatus according to various embodiments of the present invention.

As shown in FIG. 5 , the microwave power amplifier 140 may be, for example, but not limited to, an LDMOS transistor, which may be two transistors connected in series. Here, 1 and 2 are first and second gate terminals, 3 and 4 are first and second drain terminals, and 5 is a commonly connected source terminal. With this configuration, it is possible to obtain microwaves with high output through the drain terminal and the source terminals 3, 4, and 5 depending on the voltage applied to the gate terminals 1 and 2.

6 is a diagram showing an example of the antenna 160 of the microwave supply unit 100 among the vacuum microwave spray coating apparatus according to various embodiments of the present invention.

As shown in FIG. 6, the antenna 160 includes, for example, but is not limited to, at least one of a patch antenna 161, a dipole antenna 162, a monopole antenna 163, and a helical antenna 164. can be used

For the patch antenna 161, in an embodiment of the present invention, a metal pattern may be formed in the most preferred form, for example, in a square, circular, and/or complex wiring form on a microstrip substrate. Such a patch antenna 161 can derive various characteristics through small size, light weight, various pattern combinations and easy arrangement. The dipole antenna 162 is the basis of the antenna design, and a unidirectional beam pattern is formed by bending different conductors of two different poles so that the total length is λ/2. The monopole antenna 163 is similar to a dipole, but has a form in which one side is replaced with a ground instead of a conductor. In the part symmetrical to the ground, an image effect like a dipole occurs. Therefore, the length of the antenna only needs to be λ/4 instead of λ/2. The helical antenna 164 can be made in a much smaller size than a dipole or monopole at the same frequency, and the direction of the beam pattern can be made in an axial direction or a normal direction (like a dipole) depending on the spacing and method of twisting.

In addition, among the vacuum microwave spray coating apparatus according to the embodiment of the present invention, the microwave supply unit 100 is similar to the waveguide 191, but the horn antenna 165 (horn antenna) or the waveguide 191 has an open end like a funnel. A slot antenna 165 having various types of slots formed on the side surface may be used.

7 is a graph showing the reflection input coefficient (|S11|) of the antenna 160 in the microwave supply unit 100 in the vacuum microwave spray coating apparatus according to various embodiments of the present invention.

As shown in Figure 7, among the vacuum microwave spray coating apparatus according to an embodiment of the present invention, the microwave supply unit 100 has a value of S11, which means an input reflection coefficient, in the form of a resonance graph. For example, although not limited to, the smallest S11 value may appear at 433 MHz where the antenna 160 operates. That is, it can be seen that the 433 MHz microwave input to the antenna 160 is radiated to the powder to be heated as much as possible without being reflected and returned. In particular, as can be seen in the graph of FIG. 7, according to the embodiment of the present invention, at a frequency of 433 MHz, S11 has a deeper recessed shape, so that the radiation efficiency is high and the matching is good. Since the width is relatively narrow, it can be seen that the frequency bandwidth that the antenna 160 can handle is relatively narrow.

[Example]

Hereinafter, a high-hardness thick film coating layer of plasma room temperature spray coating using a mixed powder of yttria (Y2O3) and zirconia (ZrO2) prepared according to the above-described vacuum microwave spray coating apparatus and method will be described in detail.

The powder was prepared as shown in Table 1 below.

powder name	D50 (μm)
Y2O3	3.03
ZrO2	2.6

Coating conditions by the mixed powder were prepared as shown in Table 2 below.

outlet (diameter)	Print	nozzle angle	separation distance	feeder	gas type	amount of gas	degree of vacuum	coating speed	number
10mm	0.5kW	0°	50mm	1000 RPM		Ar	30 slm	0.28 Torr	100 mm/s	3rd time

Here, the diameter of the discharge port is the diameter of the spray nozzle, the output is the output by the microwave, the nozzle angle is the angle between the nozzle and the substrate (ie, the nozzle and the substrate are perpendicular), the separation distance is the separation distance between the nozzle and the substrate, the feeder RPM is the rotational speed (supply speed) of the powder by the powder supply unit, gas type is the type of transport gas, vacuum degree is the vacuum degree of the vacuum chamber, coating speed is the powder spraying speed by the spray nozzle, and number is the number of times of repeated coating of the coating layer. each means

8 is an enlarged SEM (Scanning Electron Microscope) image of the powder according to an embodiment of the present invention. Yttria powder and zirconia powder each having SEM images as shown in FIG. 8 were provided. In some examples, the powder may include yttria (Y2O3) having a particle size distribution D50 of about 3 μm to about 4 μm and zirconia (ZrO2) having a particle size distribution D50 of about 2 μm to about 3 μm.

9 is a photograph showing a coating layer according to an embodiment of the present invention. In the example shown in FIG. 9, the coating layer of (a) is yttria:zirconia = 100:0, the coating layer of (b) is yttria:zirconia = 85:15, and the coating layer of (c) is yttria:zirconia = 75 :25, the coating layer of (d) is prepared by yttria:zirconia = 65:35. Here, the ratio of yttria:zirconia may be a weight ratio (wt%). As shown in FIG. 9, no peeling phenomenon was found in all coating layers, and there was no abnormality in visual inspection.

10 is a diagram illustrating EDS (Energy Dispersive X-ray Spectroscopy) data of a coating layer (yttria:zirconia=85:15) according to an embodiment of the present invention. As shown in FIG. 10, when the weight ratio (wt%) of the yttria:zirconia mixed powder was 85:15, the resulting yttria:zirconia mixed coating layer was also observed to have a weight ratio of 85:15. That is, the weight ratio of the mixed powder of yttria:zirconia and the weight ratio of the resulting yttria:zirconia coating layer were the same. In addition to Y, Zr, and O observed in FIG. 10, Al is a material of a substrate on which a coating layer is formed, and Au is a material of a conductive layer formed on a coating layer for EDS data extraction.

11 is a diagram illustrating EDS (Energy Dispersive X-ray Spectroscopy) data of a coating layer (yttria:zirconia = 75:25) according to an embodiment of the present invention. As shown in FIG. 11, when the weight ratio (wt%) of the yttria:zirconia mixed powder was 75:25, the resulting yttria:zirconia mixed coating layer was also observed to have a weight ratio of 75:25. That is, the weight ratio of the mixed powder of yttria:zirconia and the weight ratio of the resulting yttria:zirconia coating layer were the same. In addition to Y, Zr, and O observed in FIG. 11, Al is the material of the substrate on which the coating layer is formed, and Au is the material of the conductive layer formed on the coating layer for EDS data extraction.

12 is a diagram illustrating EDS (Energy Dispersive X-ray Spectroscopy) data of a coating layer (yttria:zirconia=65:35) according to an embodiment of the present invention. As shown in FIG. 12, when the weight ratio (wt%) of the yttria:zirconia mixed powder was 65:35, the resulting yttria:zirconia mixed coating layer was also observed to have a weight ratio of 65:35. That is, the weight ratio of the mixed powder of yttria:zirconia and the weight ratio of the resulting yttria:zirconia coating layer were the same. In addition to Y, Zr, and O observed in FIG. 12, Au is the material of the conductive layer formed on the coating layer for EDS data extraction.

Table 3 below is a table showing changes in Vickers Hardness by weight ratio of the coating layer formed of the mixed powder of yttria and zirconia.

Y2O3:ZrO2	100:0	85:15	75:25	65:35
Hardness (HV)	556	603	643	633

As shown in Table 3, it can be seen that the hardness of the coating layer is the highest when the weight ratio of the mixed powder of yttria and zirconia is approximately 75:25. Here, the hardness of the coating layer formed of the mixed powder of yttria and zirconia is about 6.3 Gpa in unit conversion.

13 is a diagram showing thickness data of a coating layer according to an embodiment of the present invention. As shown in FIG. 13, when the weight ratio of yttria and zirconia was 100:0, the thickness of the coating layer was 101.650 μm, 85:15, 109.323 μm, 75:25, 107.717 μm, and 65:35. In this case, it was 81.693 μm.

That is, a coating layer of approximately 100 μm or more was obtained under the condition of zirconium/yttrium = 0.33 or less, but the thickness of the coating layer decreased under the condition of zirconium/yttrium = greater than 0.33. It is understood that this is a phenomenon caused by blasting of an already formed coating layer due to the high hardness of zirconium.

14 is a graph showing an optimal hardness-thickness relationship according to an embodiment of the present invention. In FIG. 14, the X axis means the weight ratio of yttria and zirconia, the left Y axis means the Beaker hardness (GPa), and the right Y axis means the thickness of the coating layer (μm). As shown in FIG. 14, it can be seen that the hardness and thickness of the coating layer have optimal values when the weight ratio (wt%) of yttria:zirconia is 75:25. Here, when the weight ratio of zirconia increases to about 25 or more, the hardness of about 6 GPa or more is maintained, but it can be seen that the formation rate of the coating layer per hour is lowered. It is understood that the rate is reduced due to blasting with high-hardness zirconia and saturation occurs in the hardness of the coating layer due to internal defects in the coating layer.

What has been described above is only one embodiment for carrying out the vacuum microwave spray coating apparatus, method and coating layer according to the present invention, and the present invention is not limited to the above-described embodiments, and the following claims As claimed in, anyone with ordinary knowledge in the field to which the present invention pertains without departing from the gist of the present invention will be said to have the technical spirit of the present invention to the extent that various changes can be made.

[National research and development project supporting this invention]

[Name of Department] Ministry of Trade, Industry and Energy

[Research project name] Next-generation intelligent semiconductor technology development project

[Research project number]20004294

[Research project unique number]1415172668

[Research Project Title] Development of next-generation ceramic coating technology with improved plasma resistance using low-vacuum plasma jet

[Research management institution] Korea Evaluation Institute of Industrial Technology

[Contribution rate] 100%

[Host Research Institution] IONES Co., Ltd.

[Research period] 2019. 04 01.~2021 12. 31

Claims (16)

1. a transfer gas supply unit supplying transfer gas;

   a powder supply unit for aerosolizing and supplying powder by means of the transfer gas;

   a microwave supply unit supplying heat energy by microwave to the powder so that the powder is semi-melted; and

   A coating nozzle spraying the aerosolized semi-molten powder onto a substrate to form a coating layer on the substrate;

   The vacuum microwave spray coating apparatus, wherein the substrate, the microwave supply unit, and the coating nozzle are accommodated in a vacuum chamber.
2. According to claim 1,

   The microwave supply unit

   power supply;

   A microwave generator connected to the power supply to generate microwaves;

   a microwave amplifier connected to the microwave generator to amplify microwaves;

   an antenna connected to the microwave amplifier to radiate microwaves; and

   A waveguide connected to the antenna and guiding the microwave;

   A vacuum microwave spray coating apparatus in which the coating nozzle is penetrated through the waveguide.
3. According to claim 2,

   The coating nozzle is coupled to the waveguide so that the longitudinal direction of the coating nozzle forms a right angle with respect to the longitudinal direction of the waveguide, the vacuum microwave spray coating apparatus.
4. According to claim 2,

   The antenna and the waveguide are provided inside the vacuum chamber, vacuum microwave spray coating apparatus.
5. According to claim 2,

   The antenna is provided on the outside of the vacuum chamber, the waveguide is provided on the inside of the vacuum chamber, the antenna and the waveguide are connected by an RF coaxial cable, vacuum microwave spray coating apparatus.
6. According to claim 2,

   The microwave amplification unit is a semiconductor transistor by RF amplification of a magnetron or transistor that generates microwaves by oscillation, vacuum microwave spray coating apparatus.
7. According to claim 2,

   a microwave power sensor for sensing the power of the microwave reflected from the waveguide;

   a flow sensor for sensing the flow rate of the powder; and

   Using the microwave power sensor, a microwave frequency at which reflection is the smallest is selected, and a microwave power at which the powder is semi-melted is selected using the flow sensor, and the frequency of the microwave generator and the microwave power are selected. Vacuum microwave spray coating apparatus further comprising a controller for controlling the output power of the wave amplifier.
8. a transfer gas supply step of supplying a transfer gas;

   a powder supply step of aerosolizing and supplying powder by the transport gas;

   a microwave supplying step of supplying heat energy by microwaves to the powder so that the powder is semi-melted; and

   A coating step of spraying the aerosolized semi-molten powder onto a substrate to form a coating layer on the substrate;

   A vacuum microwave spray coating method, wherein a substrate, a microwave supply and a coating nozzle are accommodated inside a vacuum chamber.
9. According to claim 8,

   The microwave supply unit

   power supply;

   A microwave generator connected to the power supply to generate microwaves;

   a microwave amplifier connected to the microwave generator to amplify microwaves;

   an antenna connected to the microwave amplifier to radiate microwaves; and

   A waveguide connected to the antenna and guiding the microwave;

   The coating nozzle is coupled through the waveguide, vacuum microwave spray coating method.
10. According to claim 9,

    The coating nozzle is coupled to the waveguide so that the longitudinal direction of the coating nozzle forms a right angle with respect to the longitudinal direction of the waveguide, vacuum microwave spray coating method.
11. According to claim 9,

    The antenna and the waveguide are provided inside the vacuum chamber, the vacuum microwave spray coating method.
12. According to claim 9,

    The antenna is provided on the outside of the vacuum chamber, the waveguide is provided on the inside of the vacuum chamber, the antenna and the waveguide are connected by an RF coaxial cable, vacuum microwave spray coating method.
13. According to claim 9,

    The microwave amplification unit is a semiconductor transistor by RF amplification of a magnetron or transistor that generates microwaves by oscillation, vacuum microwave spray coating method.
14. According to claim 9,

    a microwave power sensor for sensing the power of the microwave reflected from the waveguide;

    a flow sensor for sensing the flow rate of the powder; and

    Using the microwave power sensor, a microwave frequency at which reflection is the smallest is selected, and a microwave power at which the powder is semi-melted is selected using the flow sensor, and the frequency of the microwave generator and the microwave power are selected. Further comprising a controller for controlling the output power of the wave amplifying unit, vacuum microwave spray coating method.
15. A coating layer formed by any one of claims 8 to 14,

    The powder includes yttria (Y2O3) having a particle size distribution D50 of 3 μm to 4 μm and zirconia (ZrO2) having a particle size distribution D50 of 2 μm to 3 μm, and the wt% of yttria and zirconia is 85 to 15 to 35 vs. 65, coating layer.
16. According to claim 15,

    The thickness of the coating layer is 100㎛ to 110㎛, the hardness of the coating layer is 5GPa to 7GPa, the coating layer.

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