Preparation method of thermal spray coating and yttrium-based thermal spray coating prepared using the method

Abstract

This invention relates to a method for preparing a yttrium-based thermal spray coating, and more specifically, to a method for preparing a yttrium-based thermal spray coating, characterized in that a yttrium-based particulate powder is formed on a substrate by atmospheric plasma thermal spraying, wherein the yttrium-based particulate powder comprises a mixture of yttrium compound powder and silicon dioxide (SiO2) powder, wherein the yttrium compound is selected from any one of Y2O3, YOF, YF3, Y4Al2O9, Y3Al5O12 and YAlO3, and contains 0.1wt% to 30wt% of the silicon dioxide (SiO2), and the L value of the yttrium-based thermal spray coating is 80.0 or higher as a value measured using a colorimetric system.

Description

Preparation method of thermal spray coating and yttrium-based thermal spray coating prepared using the same The present invention relates to a method for preparing a thermal spray coating having a white or high-purity color by using yttrium-based particle powder for thermal spraying containing a silicon dioxide component. In the semiconductor manufacturing process, plasma dry etching process is becoming increasingly important in order to perform high-integration micro-machining on substrate circuits such as silicon wafers. To enable use in such an environment, proposals have been made to use materials with excellent plasma resistance for chamber components or to form a coating film on the surface of components with a substance with excellent plasma resistance to extend the life of the components. Among them, technologies for imparting new functions by coating the surface of a substrate with various materials have been used in various fields. As one of such surface coating technologies, for example, the following thermal spraying method is known: thermal spray particles made of a material such as ceramics are sprayed onto the surface of a substrate in a state softened or melted by combustion or electrical energy, thereby forming a thermal spray coating. Thermal spray coating is usually performed by melting fine powder by heating and spraying the molten powder onto the surface of the base material to be coated. The sprayed molten powder is rapidly cooled and solidified, and is laminated to the coating surface mainly by mechanical bonding. Thermal spray coating utilizes a high-temperature plasma flame to melt the powder. Plasma thermal spraying is essential for coating high-melting-point metals such as tungsten and molybdenum, as well as ceramics. Thermal spray coating not only maintains the properties of the parent material, but also produces highly functional materials exhibiting wear resistance, corrosion resistance, heat resistance, thermal barrier properties, superhardness, oxidation resistance, insulation, tribological properties, heat dissipation, and bio-functional radiation resistance. Furthermore, compared to other coating methods such as chemical vapor deposition (CVD) and physical vapor deposition (PVD), it can coat larger surfaces in a shorter time. Furthermore, in the field of semiconductor device manufacturing, microfabrication of the semiconductor substrate surface is typically performed through dry etching using plasma with halogen gases such as fluorine, chlorine, and bromine. Furthermore, after dry etching, the interior of the chamber (vacuum container) from which the semiconductor substrate is removed is cleaned using oxygen plasma. During this process, components within the chamber exposed to the highly reactive oxygen plasma or halogen gas plasma may corrode. Furthermore, when the corroded (eroded) parts break off from the components as particles, these particles can adhere to the semiconductor substrate and become foreign matter (hereinafter referred to as particles) that can cause circuit defects. Therefore, conventionally, in semiconductor device manufacturing equipment, in order to reduce the generation of particles, a thermal spray coating of a ceramic having plasma erosion resistance is provided on components exposed to plasma such as oxygen or halogen gas. Factors contributing to particle generation include, in addition to the detachment of reaction products adhering to the vacuum chamber, chamber degradation caused by the use of halogen gas plasma or oxygen plasma. Furthermore, the inventors' research has revealed that the number and size of particles generated by thermal spray coatings in dry etching environments are influenced by the strength of the bonding between the particles forming the thermal spray coating, the presence of unmelted particles, and high porosity. In particular, as the internal density of the ceramic thermal spray coating increases, the adsorption of CFx series process gases caused by defects such as pores during the dry etching process is reduced, thereby reducing etching caused by plasma ion collisions. Typically, high-density thermal spray coatings are formed using methods such as suspension plasma spray (SPS), aerosol deposition (AD), or physical vapor deposition (PVD). However, compared to the existing atmospheric plasma spray (APS), these methods all have the disadvantages of complex manufacturing methods and increased unit costs. Suspension plasma thermal spraying (SPS) utilizes a relatively high heat source, and when coating within a semiconductor chamber, the high process temperatures can cause product deformation and other issues. Furthermore, as particle size decreases, the particle flight distance shortens, shortening the operating distance between the plasma equipment and the substrate being coated, which can limit some operations. Furthermore, when water and particles are injected into the same volume as a dispersed suspension, SPS technology produces a slow film-forming rate, resulting in additional process time and high manufacturing costs. In addition, the application of aerosol deposition (AD) and physical vapor deposition (PVD) methods has technical limitations in achieving coating thicknesses of several hundred μm, and in actual coating, coating operations are restricted on substrates with complex shapes. Therefore, there is a need to develop a technology that can realize high-density thermal spray coatings by using the existing atmospheric plasma thermal spraying (APS) method. The powder of thermal spray material used in conventional APS thermal spraying methods is composed of primary particles of several microns in size, forming granular powders ranging from 20 to 40 microns. A method for increasing the density of thermal spray coatings has been proposed by reducing the primary powder constituting this thermal spray material to less than 1 micron. However, with this method, as the specific surface area of ​​the granular powder increases, heat is not evenly transferred to the primary powder within the particles, resulting in the formation of coatings containing unmelted or remelted particles on the surface or within the thermal spray layer, which can cause particle generation during dry etching processes. In addition, if the secondary particles formed by the granular powder become too small, the electrostatic attraction between the granular powders will cause the particles to aggregate, making it difficult to transfer them in the atmosphere in reality, or after the particles are transferred, there is a high possibility that they cannot be transferred to the central frame due to their low mass and are dispersed to other places. As a prior art, Korean Patent Publication No. 10-2016-0131918 (November 16, 2016) discloses a thermal spray material containing rare earth oxyhalides (RE-OX) as constituent elements. The rare earth oxyhalides contain a rare earth element (RE), oxygen (O), and a halogen element (X), with the molar ratio of halogen to rare earth element (X / RE) being 1.1 or greater. This material improves plasma resistance and properties such as porosity and hardness. Furthermore, Korean Patent Publication No. 10-2005-0013968 (published on February 5, 2005) discloses a plasma-resistant component comprising an yttrium oxide coating containing 100 ppm to 1000 ppm of silicon. However, the yttrium oxide coating containing silicon contains semiconductor components, which impart electrical properties and pose a risk of arcing. Furthermore, since the yttrium oxide coating is primarily black and cannot be distinguished from contaminants in semiconductor manufacturing processes, there is a significant concern that unnecessary cleaning steps may be added due to confusion during chamber cleaning. Existing research has confirmed that high-density coatings have excellent plasma resistance compared to other materials. To achieve high-density coatings, the distance between the base material and the plasma gun is shortened during coating. This increases the particle velocity and reduces the particle cooling time, allowing the coating to be applied while the particles are fully melted, resulting in a high-density coating. However, due to the short distance between the particles, the molten particles have a shorter flight distance, resulting in insufficient oxygen supply and deacidification. This can cause the coating to change color, or turn black in specific areas or all areas. A coating color that differs from the original color can cause the following problems. Black areas or spots can be mistaken for process contaminants, causing unwanted coating removal during the cleaning process. In this case, the color change in the coating can alter the radiation absorption rate of the plasma during the etching process, causing the process conditions to deviate from expectations. Specifically, the black color of the coating may increase the temperature of the coating by absorbing radiation, thereby increasing the etching rate. In addition, uneven coating color may cause differences in radiation absorption, resulting in localized temperature differences. The resulting thermal expansion differences can lead to the generation of particles or delamination due to thermal stress. In addition, since the deacidified area of ​​the coating does not form a complete stoichiometry, the energy is unstable, which becomes the cause of a local increase in the etching rate. On the other hand, heat treatment of the coating in an oxygen atmosphere can restore black spots or black spots to white, but this can cause melting of the base metal. Furthermore, the high temperatures at which ceramic coatings are heat treated can cause deformation of the base metal. Furthermore, there are concerns about delamination due to the difference in thermal expansion between the coating and base metal, or oxidation of the base metal during heat treatment in an oxygen atmosphere. As described above, even though technologies for producing yttrium-based thermal spray coatings from which black spots have been removed have been proposed to overcome the limitations of the physical properties of yttrium oxide or yttrium fluoride thermal spray materials, there is a continued industrial demand for a technology for producing dense thermal spray coatings having uniform color and improved plasma resistance. [Prior Art Documents] [Patent Documents] Patent Document 1: Korean Patent Publication No. 10-2016-0131918 (November 16, 2016). Patent Document 2: Korean Patent Publication No. 10-2005-0013968 (February 5, 2005). [Problems to be solved by the invention] The main object of the present invention is to solve the above-mentioned problems by including silica particles in the thermal spraying granular powder, thereby improving the melting efficiency and forming a coating with low porosity and high hardness. Furthermore, the problem of black spots or black coloration in thermal spray coatings that undergo deoxidation can be improved, and the color of the thermal spray coating can be uniformly adjusted by adjusting the addition ratio of silicon dioxide. [Means for Solving the Problems] In order to achieve the above-mentioned object, an embodiment of the present invention provides a method for preparing a yttrium-based thermal spray coating, characterized in that yttrium-based granular powder is sprayed on a substrate by atmospheric plasma thermal spraying, thereby forming a yttrium-based thermal spray coating, wherein the yttrium-based granular powder comprises yttrium compound powder and silicon dioxide (SiO 2) a mixture of powders, wherein the yttrium compound is selected from Y 2O 3. YOF, YF 3. Y 4Al 2O 9. Y 3Al 5O 12 and YAlO 3, comprising 0.1wt% to 30wt% of the silicon dioxide (SiO 2) The L value of the yttrium-based thermal spray coating is 80.0 or greater, as a value measured using a colorimetric system under plasma exposure conditions. In a preferred embodiment of the present invention, the granular powder can be prepared by mixing yttrium compound powder having an average diameter of 0.1 μm to 10 μm and silicon dioxide powder having an average diameter of 0.1 μm to 10 μm. In a preferred embodiment of the present invention, the atmospheric plasma thermal spraying may use a plasma gas containing an inert gas with a flow rate of 30 NLPM to 70 NLPM. In a preferred embodiment of the present invention, the plasma generating power of the atmospheric plasma thermal spraying may be in the range of 20 kW to 130 kW. In a preferred embodiment of the present invention, for the atmospheric plasma thermal spraying, the spray unit can be arranged at a distance of 50 mm to 400 mm relative to the upper surface of the substrate, and the feeder can be moved at a speed of 10 g / min to 50 g / min. In another preferred embodiment of the present invention, the present invention provides a yttrium-based thermal spray coating formed by the method for preparing the yttrium-based thermal spray coating. In a preferred embodiment of the present invention, the yttrium-based thermal spray coating may contain 0.01 at % to 5 at % of silicon (Si) element. In a preferred embodiment of the present invention, the yttrium compound may be yttrium oxide (Y 2O 3) The yttrium oxide may have a crystal structure comprising 1 wt % to 50 wt % of a monoclinic system. In a preferred embodiment of the present invention, the porosity of the yttrium-based thermal spray coating may be less than 2%. In a preferred embodiment of the present invention, the yttrium-based thermal spray coating may contain less than 0.1 at% of silicon (Si) element, and as values ​​measured using a colorimetric system under plasma exposure conditions, the a value of the yttrium-based thermal spray coating may be less than 1, the b value may be less than 1, and the coating may appear white. In a preferred embodiment of the present invention, the yttrium-based thermal spray coating may contain 0.1 at % to 1.0 at % of silicon (Si) element, and as values ​​measured using a colorimetric system under plasma exposure conditions, the a value of the yttrium-based thermal spray coating may be less than 5, the b value may be less than 5, and the coating may appear red. In a preferred embodiment of the present invention, the yttrium-based thermal spray coating contains 1.0 at % to 5.0 at % of silicon (Si) element. As values ​​measured using a colorimetric system under plasma exposure conditions, the a value of the yttrium-based thermal spray coating can be less than 1, the b value can be less than 10, and the coating can appear yellow. In a preferred embodiment of the present invention, the main peak of the yttrium-based thermal spray coating obtained by XRD analysis can be above 29.1°. The thermal spray coating prepared from the present invention containing silica component thermal spray coating with titanium-based particle powder inhibits the formation of black spots or black, and the white thermal spray coating color uniform, thereby causing localized heat absorption and temperature changes during etching process. In addition, for the thermal spray coating of the present invention, due to its low porosity and excellent hardness, it has excellent durability when used as a coating material for components in the semiconductor cavity, and inhibits the phenomenon of the coating being stripped based on the etching phenomenon, which can help to improve the yield of the semiconductor wafer. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as is commonly understood by ordinary technical personnel in the technical field to which the invention belongs. Typically, the nomenclature used in this specification is well known and commonly used in the art. Throughout the description of the invention, when a part “includes” a certain constituent element, it means that other constituent elements may also be included and not meant to exclude other constituent elements so long as there is no particularly contrary account. In the semiconductor preparation process, gate etching devices, insulating film etching devices, resist film etching devices, sputtering devices, and CVD devices are used. On the other hand, in liquid crystal fabrication processes, etching devices are used to form thin film transistors. In addition, in these manufacturing devices, for the purpose of achieving high integration through micromachining, etc., a configuration with a plasma generating mechanism is adopted. In these preparation processes, as treatment gases, halogen-based corrosive gases such as fluorine and chlorine groups are used in the apparatus due to their high reactivity. As a fluorine-based gas, SF can be included 6. CF 4. CHF 3. ClF 3. HF and NF 3 etc., as chlorine-based gases, may contain Cl 2. BCl 3. HCl, CCl 4 and SiCl 4 etc., and by introducing microwaves or high frequencies, etc., into the atmosphere in which these gases are introduced, these gases will be plasmaized. In device components exposed to these halogen-based gases or plasma thereof, it is required to have very few metals on its surface except material components and to have high corrosion resistance. Accordingly, the object of the present invention is to provide a method for the preparation of thermal spray coatings for coating components for plasma etching devices with uniform color and excellent plasma resistance. The present invention provides a method for preparing a yttrium-based thermal spray coating, characterized in that a yttrium-based thermal spray coating is formed on a substrate by atmospheric plasma thermal spraying of yttrium-based particle powder, wherein the yttrium-based particle powder comprises yttrium compound powder and silicon dioxide (SiO 2) a mixture of powders, wherein the yttrium compound is selected from Y 2O 3. YOF, YF 3. Y 4Al 2O 9. Y 3Al 5O 12 and YAlO 3, comprising 0.1wt% to 30wt% of the silicon dioxide (SiO 2) The L value of the yttrium-based thermal spray coating is 80.0 or greater, as a value measured using a colorimetric system under plasma exposure conditions. The “plasma exposure conditions” mentioned above are to use a direct current (DC) plasma gun, in an 80kW plasma containing Ar gas and H gas, at a distance of 70mm from the gun nozzle inlet, to expose the coating for 5 minutes, and the color is based on the 30 seconds after exposure. The granular powder may be prepared by mixing yttrium compound powder having an average diameter of 0.1 μm to 10 μm and 70% to 99.9% by mass and silicon dioxide powder having an average diameter of 0.1 μm to 10 μm and 0.1% to 30% by mass. In addition, preferably, the compound is selected from Y 2O 3. YOF, YF 3. Y 4Al 2O 9. Y 3Al 5O 12 and YAlO The average diameter of the primary particles of the yttrium compound powder and the silicon dioxide powder in 3 may be 0.1 μm to 30 μm, more preferably 0.2 μm to 15 μm. When the average diameter of the yttrium compound powder and the silica powder is less than approximately 0.1 μm, it may be difficult to control the powder, making it difficult to form spherical particles and controlling physical properties. Furthermore, when the average diameter of the primary particles of the yttrium compound powder and the silica powder exceeds approximately 30 μm, the average diameter of the particles formed by the aggregation of the primary powders may become too large, making it difficult to form a uniform thermal spray coating. In addition, the size of the granular powder of the present invention may be 1 μm to 50 μm, preferably 5 μm to 40 μm, and more preferably 10 μm to 30 μm. If the size of the yttrium-based thermal spraying particles is less than 1 μm, the powder's fluidity during thermal spraying is low, preventing the formation of a uniform film. Furthermore, the powder oxidizes before being transferred to the frame or fails to reach the center of the frame, making it difficult to achieve the droplet flight speed and heat required to form a dense film, resulting in a film with high porosity or low hardness. If the average diameter of the yttrium-based particles exceeds 50 μm, the particles' melting specific surface area decreases, preventing complete melting. This results in unmelted portions within the coating, making it difficult to meet the quality requirements of the thermal spray coating required by the present invention. Since the fluidity of yttrium-based particle powder for thermal spraying is an important factor affecting the quality of thermal sprayed films, it is best to make it into a spherical shape. Otherwise, when preparing the thermal spray layer, the specified amount of powder cannot be transferred to the frame, and it may also be impossible to form the film of the required level. Furthermore, in the present invention, the substrate to be coated with the thermal spray coating is not particularly limited. For example, as long as the substrate comprises a material capable of providing the required resistance by thermal spraying of the thermal spray material, its material and shape are not particularly limited. The material constituting the thermal spray substrate is preferably selected from at least one combination of aluminum, nickel, chromium, zinc, and alloys thereof, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, and quartz glass, which are used to form components of semiconductor manufacturing equipment. Such a substrate may be, for example, a component constituting a semiconductor device manufacturing apparatus, or may be a component exposed to highly reactive oxygen gas plasma or halogen gas plasma. Preferably, before plasma thermal spraying, the substrate surface is treated according to the ceramic thermal spraying operation standard specified in JIS H 9302. For example, after removing rust or grease from the substrate surface, the substrate surface is treated by spraying Al 2O 3 and SiC grinding particles to roughen the surface and pre-treat it to a state where fluoride thermal spraying particle powder is easily attached. The spray gun in the atmospheric plasma thermal spraying utilizes a plasma flame to melt the coating material and thermally spray the molten coating material onto the substrate. For example, the plasma flame may be heated by gases including argon (Ar), nitrogen (N 2) Hydrogen (H 2) and helium (He) and other plasma gases are dissociated to form. For the atmospheric plasma thermal spraying as a thermal spraying process variable, preferably, the flow rate of the inert gas can be 20NLPM to 100NLPM, and the flow rate of the hydrogen can be 1NLPM to 50NLPM. More preferably, the flow rate of the inert gas can be 30NLPM to 70NLPM, and the flow rate of the hydrogen can be 5NLPM to 30NLPM. When the inert gas is introduced at a flow rate of less than 30 NLPM, the output power is low and the overall heat capacity is reduced, thereby reducing the porosity and film formation speed of the thermal spray coating. When the inert gas is introduced at a flow rate greater than 70 NLPM, the power becomes too high, inducing etching of consumables. When hydrogen is introduced at a flow rate of less than 1 NLPM, the plasma power is too low to ignite. When hydrogen is introduced at a flow rate greater than 50 NLPM, the plasma gas becomes severely turbulent, resulting in increased interaction with the surrounding air. In addition, preferably, the plasma generating power of the atmospheric plasma thermal spraying can be 20kW to 130kW, more preferably, it can be 40kW to 110kW. When the power is less than 20kW, the powder cannot be fully melted and no coating is formed, or unmelted particles are formed inside the coating. When the power exceeds 130kW, a large amount of heat energy is provided, which may cause the coating to peel off. Preferably, for the plasma thermal spray coating, the spray unit may be disposed at a distance of 50 mm to 400 mm relative to the upper surface of the substrate, more preferably, at a distance of 100 mm to 200 mm relative to the upper surface of the substrate. When the distance between the spray unit and the surface of the substrate is approximately less than 50 mm, it is difficult to prepare a uniform thermal spray coating because the working distance is too close. When the distance is greater than 400 mm, as the flight distance of the yttrium-based granular powder increases, the molten granular powder reaching the substrate hardens, and pores remain in the layer, forming a layer with low density. At this time, when the distance between the spray unit and the substrate surface is 50 mm to 400 mm, the feeder feed rate of the spray unit is preferably 10 g / min to 50 g / min. If the feeder feed rate exceeds 50 g / min and the amount of feeder powder supplied per unit time is excessive, it becomes difficult to produce a uniform thermal spray coating, and some feeder powder fails to fully melt, resulting in increased porosity in the thermal spray coating. Furthermore, when the feeder feed rate is less than 10 g / min, the insufficient feeder feed rate leads to pulsation of the thermal spray coating, resulting in reduced uniformity of the thermal spray coating and lower production yield. In the plasma thermal spraying method, the yttrium-based thermal spraying layer is preferably formed to a thickness of 50 μm to 500 μm. Existing yttrium-based thermal sprayed films form high porosity in the coating. In contrast, in the present invention, a silicon dioxide component is added as a primary powder to lower the melting point of the yttrium-based compound to produce a white yttrium-based thermal sprayed coating with low porosity. Therefore, compared with existing thermal spray coatings, the yttrium-based thermal spray coating prepared by the method has an excellent porosity level, and is therefore suitable for semiconductor chambers used in existing etching processes, exhibits excellent durability, and suppresses the phenomenon of coating detachment caused by etching gas. At this time, for the yttrium-based thermal spray coating of the present invention, the silicon element can be partially vaporized during the preparation process of the thermal spray coating, thereby containing 0.01 at % to 5 at % of the silicon element relative to the yttrium-based thermal spray coating. In addition, in the yttrium-based thermal spray coating of the present invention, when the yttrium compound is yttrium oxide (Y 2O 3), the yttrium oxide may contain 1 wt% to 50 wt% of a monoclinic morphology. 2O 3) The monoclinic crystal structure improves the bonding strength between yttrium oxide powders and helps to reduce the size of pores in the thermal spray coating. As an example, the porosity of the yttrium-based thermal spray coating formed by the method for preparing the yttrium-based thermal spray coating may be less than 2.0%, preferably less than 1.5%, and more preferably less than 1%. In addition, the yttrium-based thermal spray coating of the present invention can exhibit a uniform color when exposed to plasma, thereby suppressing the generation of particles in the thermal spray coating or peeling of the thermal spray coating due to thermal expansion of the coating caused by local temperature differences. As one embodiment, the yttrium-based thermal spray coating of the present invention contains less than 0.1 at % of silicon (Si) element. In particular, as values ​​measured using a colorimetric system under plasma exposure conditions, the a value may be less than 1, the b value may be less than 1, and the coating may exhibit a uniform white color. In addition, as one embodiment, the yttrium-based thermal spray coating of the present invention contains 0.1 at % to 1.0 at % of silicon (Si) element. In particular, as values ​​measured using a colorimetric system under plasma exposure conditions, the a value can be 5 or less, the b value can be 5 or less, and the coating can exhibit a uniform red color. In addition, as one embodiment, the yttrium-based thermal spray coating of the present invention contains 1.0 at % to 5.0 at % of silicon (Si) element. In particular, as values ​​measured using a colorimetric system under plasma exposure conditions, the a value can be less than 1, the b value can be less than 10, and the coating can exhibit a uniform yellow color. The “plasma exposure condition” is to use a direct current (DC) plasma gun, expose the coating for 5 minutes in an 80 kW plasma containing Ar and H gases at a distance of 70 mm from the gun nozzle inlet, and the color is based on the 30 seconds after exposure. In addition, as an embodiment, the main peak of the yttrium-based thermal spray coating obtained by XRD analysis may be greater than 29.1°. Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are only for illustrating the present invention and the present invention is not limited to the following examples. Preparation Example 1~6 After mixing yttrium oxide powder and silicon dioxide powder with a binder, the mixture was spray-dried to obtain a granulated powder. The granulated powder was then defatted and sintered to obtain a sintered powder. The experimental conditions used in each preparation example, including the size and mixing ratio of the yttrium oxide and silicon dioxide powders, are shown in Table 1 below. [ surface 1] Comparative Example 1~6 Using the thermal spray materials and plasma guns prepared in Preparation Examples 1, 2, and 6, argon and hydrogen were flowed as heat source gases. While the thermal spray gun was moving, plasma was generated at a power of 20 kW. The generated plasma melted the raw material powder, forming a coating film on the base material. The coating film thickness ranged from 100 μm to 200 μm. The experimental conditions are shown in Table 2 below. [ surface 2] Example 1~6 Using the thermal spray materials and plasma gun prepared in Preparation Examples 3 to 5, argon and hydrogen were flowed as heat source gases. While the thermal spray gun was moving, plasma was generated at a power of 20 kW. The generated plasma melted the raw material powder, forming a coating film on the base material. The coating film thickness ranged from 100 μm to 200 μm. The experimental conditions are shown in Table 3 below. [ surface 3] Experimental example 1 : Observation of thermal spray coatings The porosity of the thermal spray coating was measured as follows. The thermal spray coating was cut into a plane perpendicular to the substrate surface. The resulting cross-section was then resin-embedded and polished, and an image of the cross-section was captured using an electron microscope (JEOL, JS-6010). This image was analyzed using image analysis software (MEDIA CYBERNETICS, Image Pro) to determine the area of ​​pores in the measured cross-sectional image. The porosity was then calculated by calculating the ratio of this pore area to the overall cross-sectional area. The porosity, calculated from the area of ​​pores appearing in the cross-sectional view of the thermal spray coating, is shown in Table 4. The porosity of the thermal spray coatings prepared in Comparative Examples 1 and 2 was 2.5% or higher. In contrast, the porosity of Examples 1 to 6 was 2.0% or lower, indicating that the yttrium-based thermal spray coatings of the present invention have a higher density than conventional thermal spray coatings. [ surface 4] Experimental example 2 Hardness Measurement: The "Hardness" column in Table 4 shows the Vickers hardness measurement results for each thermal spray coating. Vickers hardness was measured using a microhardness tester (company name, model name) and measured using a diamond indenter with a 136° angle. The Vickers hardness (Hv0.05) was obtained by applying a test force of 0.05 kgf to the indenter. As shown in Table 2 above, it was confirmed that the thermal spray coatings of Examples 1 to 6 showed hardness in a range similar to that of the thermal spray coatings of Comparative Examples 1 to 6. Experimental example 3 : Surface roughness Ra Measurement The surface roughness Ra (Average Roughness) of the coating films prepared in the Examples and Comparative Examples of the present invention was measured in accordance with JIS 2001, using a λc of 0.8, a λs of 2.5, five measurement intervals, and a measuring tip movement speed of 0.5 mm / s. A Mitutoyo roughness meter (Model: SJ-201) was used. The results are reported in Table 4 above. Experimental example 4 : XRD Measurement The lattice deformation of the coating films prepared in the examples and comparative examples of the present invention was measured using an XRD device (model name: Empyrean) from Malvern Panalytical. The results are shown in FIG1 and Table 5 below. As shown in Table 1 below, when XRD is measured, as the additive content increases, the position (angle) of the measured peak moves in the increasing direction. This is because Si, which has a smaller atomic radius, 4+ Replace Y 3+ The lattice shrinkage occurs simultaneously with the site. [ surface 5] Experimental example 5 : PL Measurement In PL measurement, a surface or a cross section was polished using a He-Cd laser source, a wavelength of 325 nm, and a power of 20 mW, and measurement was performed under the condition that the roughness Ra was 0.1 μm or less. When measuring PL, the main peak was measured to be in the range of 380nm to 440nm, and the sub-peak was measured to be in the range of 780nm to 840nm. In the PL measurement data of Comparative Example 1, when the base main peak was set to 1, the relative intensity ranges of the main peak and sub-peak of PL obtained under other conditions are shown in Figure 2 and Table 5. Experimental example 6 : XPS Measurement The silicon (Si) element ratios of the coating films prepared in the examples and comparative examples of the present invention were measured using an XPS device (model name: K-Alpha+) manufactured by Thermo Fisher Scientific. The results are shown in Table 5 above. When XPS measurement is performed by depth profiling, the saturation value after etching for more than 400 seconds is used as the reference. Experimental example 7 : Color data ( CIELab )Measurement The color data of the coating films prepared in the examples and comparative examples of the present invention were measured using a colorimeter (model name: CR-310) manufactured by Konica Minolta. The results are shown in Table 5 above. The coating was exposed for 5 minutes using a direct current (DC) plasma gun in an 80 kW plasma of Ar and H gases at a distance of 70 mm from the gun nozzle inlet, and the color data was measured using a colorimeter within 30 seconds after the end of exposure. While specific portions of the present invention have been described in detail above, it will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments and the scope of the present invention is not limited thereby. Therefore, the substantial scope of the present invention is defined by the appended claims and their equivalents. none FIG1 shows X-ray diffraction analysis (XRD) results of thermal spray coatings of Comparative Example 1 and Examples 2, 4, and 6 of the present invention. FIG. 2 shows the photoluminescence (PL) results of the thermal spray coatings of Comparative Example 1 and Examples 2, 4, and 6 of the present invention.

Claims

1. A method for preparing a yttrium-based thermal spray coating, characterized in that a yttrium-based thermal spray coating is formed on a substrate by atmospheric plasma thermal spraying of yttrium-based particulate powder, wherein the yttrium-based particulate powder comprises a mixture of yttrium compound powder and silicon dioxide powder, wherein the yttrium compound is selected from any one of Y2O3, YOF, YF3, Y4Al2O9, Y3Al5O12 and YAlO3, wherein the yttrium-based particulate powder comprises 10wt% to 30wt% of the silicon dioxide, wherein the plasma generation power for the atmospheric plasma thermal spraying is in the range of 20kW to 130kW, and wherein the yttrium-based thermal spray coating comprises 0.01at% to 5at% silicon element, and the L value of the yttrium-based thermal spray coating is 80.0 or higher as a value measured using a colorimetric system under plasma exposure conditions.

2. The method for preparing a yttrium-based thermal spray coating as described in claim 1, wherein, The yttrium-based particle powder is prepared by mixing yttrium compound powder with an average diameter of 0.1 μm to 10 μm and silicon dioxide powder with an average diameter of 0.1 μm to 10 μm.

3. The method for preparing a yttrium-based thermal spray coating as described in claim 1, wherein, For the atmospheric plasma thermal spraying, plasma gas containing inactive gases at a flow rate of 30 NLPM to 70 NLPM is used.

4. The method for preparing a yttrium-based thermal spray coating as described in claim 1, wherein, For the atmospheric plasma thermal spraying, the spraying unit is positioned at a distance of 50 mm to 400 mm relative to the upper surface of the substrate, and the feeder's conveying speed is 10 g / min to 50 g / min.

5. A yttrium-based thermal spray coating, characterized in that the yttrium-based thermal spray coating is formed by a method for preparing a yttrium-based thermal spray coating as described in any one of claims 1 to 4.

6. The yttrium-based thermal spray coating as described in claim 5, wherein, The yttrium compound is yttrium oxide, and the crystal structure of the yttrium oxide contains 1 wt% to 50 wt% of a monoclinic crystal system.

7. The yttrium-based thermal spray coating as described in claim 5, wherein, The porosity of the yttrium-based thermal spray coating is less than 2%.

8. The yttrium-based thermal spray coating as described in claim 5, wherein, The yttrium-based thermal spray coating contains less than 0.1 at% silicon element. As measured using a colorimetric system under plasma exposure conditions, the yttrium-based thermal spray coating has an a value of less than 1, a b value of less than 1, and exhibits a white color.

9. The yttrium-based thermal spray coating as described in claim 5, wherein, The yttrium-based thermal spray coating contains 0.1 at% to 1.0 at% silicon element. As measured using a colorimetric system under plasma exposure conditions, the yttrium-based thermal spray coating has an a value of less than 5, a b value of less than 5, and exhibits a red color.

10. The yttrium-based thermal spray coating as described in claim 5, wherein, The yttrium-based thermal spray coating contains 1.0 at% to 5.0 at% silicon element. As measured using a colorimetric system under plasma exposure conditions, the yttrium-based thermal spray coating has an a value of less than 1, a b value of less than 10, and exhibits a yellow color.

11. The yttrium-based thermal spray coating as described in claim 5, wherein, The main peak value of the yttrium-based thermal spray coating obtained by XRD analysis is above 29.1°.

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