Method for manufacturing a high-density yttria coating by atmospheric plasma spraying and a yttria spray coating manufactured using the same.

Abstract

The present invention relates to a method for producing an yttria thermal spray coating, and more specifically to a method for producing an yttria thermal spray coating that has low porosity, is very dense, and has excellent plasma resistance, by positioning a spray unit at a distance of 50 to 130 mm from a substrate, atmospheric plasma spraying Y2O3 thermal spray powder onto the substrate to form an yttria thermal spray coating, and supplying water at a rate of 50 to 400 ml / min at a position 25 to 50 mm from a plasma generating nozzle together with the Y2O3 thermal spray powder.

Description

Technical Field

[0001] The present invention relates to a method for producing a high-density yttria sprayed coating by using an atmospheric plasma spraying method for Y2O3 spraying powder.

Background Art

[0002] For performing fine processing for high integration of substrate circuits such as silicon wafers in semiconductor manufacturing processes, the importance of the plasma dry etching process is increasingly becoming important.

[0003] In order to be used in such an environment, a method has been proposed in which a material excellent in plasma resistance is used as a chamber member, or a coating is formed on the surface of the member with a material excellent in plasma resistance to extend the life of the member.

[0004] Among these, a technique of imparting new functionality by coating the surface of a substrate with various materials has been conventionally used in various fields. As one of this surface coating technique, for example, a spraying method for forming a sprayed coating formed by spraying molten particles made of a material such as ceramics on the surface of a substrate in a softened or molten state by combustion or electric energy is known.

[0005] Generally, a sprayed coating is performed by heating and melting fine powder and spraying the melted powder toward the coating surface of a base material. The sprayed melted powder is rapidly cooled and the melted powder solidifies, and is laminated on the coating target surface mainly by mechanical bonding force.

[0006] Of the aforementioned thermal spray coatings, plasma thermal spray coating, which melts the powder using a high-temperature plasma flame, is always used for coating metals such as tungsten and molybdenum with high melting points and ceramics. This thermal spray coating is advantageous not only for producing high-performance materials that exhibit properties such as wear resistance, corrosion resistance, heat resistance and thermal barrier, cemented carbide, oxidation resistance, insulation, friction properties, heat dissipation, and bio-functional radiation resistance by utilizing the material properties of the base material, but also for rapidly coating large areas of objects compared to other coating methods such as chemical vapor deposition and physical vapor deposition.

[0007] In the manufacturing of semiconductor devices and the like, microfabrication of the surface of semiconductor substrates is generally performed by dry etching using a plasma of halogen gases such as fluorine, chlorine, and bromine. After dry etching, the inside of the chamber (vacuum container) from which the semiconductor substrate was removed is cleaned using oxygen gas plasma. At this time, components exposed to the highly reactive oxygen gas plasma or halogen gas plasma inside the chamber may corrode. When the corroded (eroded) parts detach from these components in particulate form, these particles can adhere to the semiconductor substrate and become foreign matter (hereinafter referred to as "particles") that cause defects in the circuit.

[0008] Therefore, in semiconductor device manufacturing equipment, it has been common practice to apply a thermal spray coating of ceramics with plasma erosion resistance to components exposed to plasma such as oxygen gas or halogen gas, in order to reduce particle generation.

[0009] Factors contributing to the generation of these particles include the detachment of reaction products adhering to the inside of the vacuum chamber, as well as the deterioration of the chamber due to the use of halogen gas plasma or oxygen gas plasma. Furthermore, our research has shown that the number and size of particles generated from a thermal spray coating under a dry etching environment are due to the strength of the bonding force between the particles constituting the thermal spray coating, the presence of unmelted particles, or a high porosity.

[0010] In particular, the higher the density of the coating inside the thermal spray film of ceramics, the less adsorption of CFx-based process gases due to defects such as pores in the dry etching process, thereby reducing etching by plasma ion collisions.

[0011] Generally, suspension plasma spraying (SPS) is a coating method used to form high-density thermal spray coatings. However, SPS has the disadvantage of being more complex and costly to manufacture compared to air plasma spraying (APS).

[0012] Suspension plasma spraying (SPS) technology involves high process temperatures during semiconductor chamber coating due to the relatively high heat source, leading to problems such as product deformation. As particle size decreases, the particle flight distance shortens, bringing the working distance between the plasma device and the substrate to be coated closer, partially limiting the work process. Furthermore, SPS technology, with its suspension state where water and particles are dispersed, results in a low film deposition rate for the same volume injection, requiring additional process time and leading to high manufacturing costs.

[0013] Furthermore, as semiconductor process conditions become more stringent, stable thick film formation of 150 μm or more is required with high-power RF plasma equipment. However, with SPS technology, forming thick films of 150 μm or more results in internal cracks and delamination due to residual stress, making it technically difficult to achieve coating thicknesses in the hundreds of micrometer range.

[0014] Therefore, it is necessary to develop a technology that can achieve high-density sprayed coatings using existing atmospheric plasma spraying (APS) methods.

[0015] The powder used in conventional APS thermal spraying methods consists of primary particles of several micrometers in size, which aggregate to form granular powder of 20-40 micrometers. However, a method has been proposed to increase the density of the thermal spray coating by making the primary powder constituting such a thermal spray material smaller to 1 micrometer or less. However, in such a method, as the specific surface area of ​​the granular powder increases, heat is not uniformly transferred to the primary powder inside the particles, resulting in the formation of a coating on or inside the thermal spray coating that includes unmelted or remelted states, which act as a cause of particle generation in the dry etching process.

[0016] Furthermore, if the secondary particles formed from granular powder are too small, the electrostatic attraction between the granular powder particles will cause them to clump together, making air transport practically impossible. Alternatively, the low particle mass after transport may prevent them from reaching the central frame, making them likely to scatter to other locations.

[0017] Another method for creating a high-density coating layer is to coat the material with a small separation distance (the distance between the base material and the plasma). This allows for the formation of a relatively high-density coating due to the high kinetic energy and short cooling time of the molten particles, i.e., the spray powder.

[0018] However, the short separation distance reduces the travel distance of the molten spray powder, causing deoxidation. This results in the surface of the sprayed coating turning black in part or entirely, and this unusual coating color can lead to the following problems.

[0019] When the thermal spray coating is black, it is difficult to distinguish it from contaminants after use in the semiconductor process, making it difficult to predict when cleaning and recoating cycles will occur. Furthermore, changes in the color of the thermal spray coating necessitate altering the emissivity and thus changing the semiconductor process conditions.

[0020] To solve these problems, it is possible to restore the surface of the blackened thermal spray coating to white by heat treatment in an atmospheric (oxygen-containing) environment. However, this additional heat treatment process leads to a decrease in production speed and an increase in manufacturing costs. In addition, since many semiconductor chambers are made of metallic materials, there is a possibility of thermal damage to the base material during the heat treatment process.

[0021] As a conventional technology, the thermal spray material disclosed in Korean Published Patent No. 10-2016-0131918 (November 16, 2016) contains a rare earth element oxyhalide (RE-OX) as constituent elements, with rare earth elements (RE), oxygen (O), and halogen elements (X), and the molar ratio of halogen elements to rare earth elements (X / RE) being 1.1 or higher. This has resulted in improved plasma resistance and improved properties such as porosity and hardness.

[0022] As mentioned above, despite the fact that technologies have been proposed to manufacture yttrium oxyfluoride thermal spray materials with improved properties such as porosity and hardness in order to overcome the limitations of conventional yttrium oxide thermal spray materials, there is a continuing demand from an industrial perspective for the development of technologies to manufacture dense thermal spray coatings for improved plasma resistance. [Overview of the project] [Problems that the invention aims to solve]

[0023] The main objective of the present invention is to solve the above-mentioned problems and to provide a method for producing a dense yttrium oxide thermal spray coating by supplying water (distilled water) together with the Y2O3 thermal spray powder to prevent the deoxidation phenomenon of yttrium oxide and prevent the progression of color changes in the thermal spray coating, and by arranging the spray units at a relatively close distance (distance between the base material and the plasma) and utilizing the large kinetic energy of the thermal spray powder. [Means for solving the problem]

[0024] To achieve the above object, in one embodiment of the present invention, a spray unit is disposed at a distance of 50 to 130 mm from a substrate, and a powder for atmospheric plasma spraying of Y2O3 is sprayed onto the substrate to form a yttria sprayed coating on the substrate, and water is supplied at a rate of 50 to 400 ml / min together with the powder for spraying Y2O3. A method for manufacturing a yttria sprayed coating is provided, which is characterized by this.

[0025] In a preferred embodiment of the present invention, the atmospheric plasma spraying can dispose the spray unit at a distance of 80 to 120 mm from the substrate.

[0026] In a preferred embodiment of the present invention, water can be supplied at a rate of 200 to 350 ml / min together with the powder for spraying Y2O3.

[0027] In a preferred embodiment of the present invention, the position where the water is supplied can be a distance of 2:8 to 8:2 between the plasma forming nozzle and the substrate.

[0028] In a preferred embodiment of the present invention, the position where the water is supplied can be a distance of 3:7 to 5:5 between the plasma forming nozzle and the substrate.

[0029] In a preferred embodiment of the present invention, the position where the water is supplied can be 25 to 50 mm from the plasma forming nozzle.

[0030] In a preferred embodiment of the present invention, the four water supply nozzles for supplying water are arranged at intervals of 90° from each other, and water can be supplied from four directions.

[0031] In a preferred embodiment of the present invention, the eight water supply nozzles for supplying water are arranged at intervals of 45° from each other, and water can be supplied from eight directions.

[0032] In a preferred embodiment of the present invention, the orifice used in the water supply nozzle is circular, and the size of the orifice can be 0.007 to 0.011 inches.

[0033] In a preferred embodiment of the present invention, the average particle size of the Y2O3 thermal spray powder may be 5 to 60 μm.

[0034] In a preferred embodiment of the present invention, the thickness of the yttria thermal spray coating may be 100 to 300 μm.

[0035] Another preferred embodiment of the present invention provides an yttria thermal spray coating formed by the method for producing the yttria thermal spray coating.

[0036] In a preferred embodiment of the present invention, the colorimeter measurement L of the yttria thermal spray coating may be 85 or higher.

[0037] In one preferred embodiment of the present invention, the porosity of the yttria thermal spray coating may be less than 2.6%.

[0038] In one preferred embodiment of the present invention, the porosity of the yttria thermal spray coating may be less than 1.0%. [Effects of the Invention]

[0039] The yttria thermal spray coating produced by the present invention forms a high-density whitening thermal spray coating layer of 1.5% or less, reducing the etching rate by process gas in the dry etching process, and exhibiting excellent durability when used as a coating material for semiconductor chamber internal components. The phenomenon of delamination of the coating due to etching is suppressed, contributing to improved semiconductor wafer yield.

[0040] Furthermore, the method for manufacturing an yttria thermal spray coating according to the present invention provides a reasonable process time by whitening the surface of the coating layer during the manufacturing process, and can provide a high-quality thermal spray coating layer without any additional cost increases. [Brief explanation of the drawing]

[0041] [Figure 1]Figure 1 is a schematic diagram illustrating the supply of water (distilled water) in the method for producing an yttria thermal spray coating according to the present invention. [Figure 2] Figure 2 shows scanning electron microscope (SEM) images of the surface of the thermal spray coating according to (a) Comparative Example 1, (b) Comparative Example 2, (c) Example 1, and (d) Example 2 of the present invention. [Figure 3] Figure 3 shows low-magnification scanning electron microscope (SEM) images of the side surface of the thermal spray coating according to (a) Comparative Example 1, (b) Comparative Example 2, (c) Example 1, and (d) Example 2 of the present invention. [Figure 4] Figure 4 shows high-magnification scanning electron microscope (SEM) images of the side surface of the thermal spray coating according to (a) Comparative Example 1, (b) Comparative Example 2, (c) Example 1, and (d) Example 2 of the present invention. [Figure 5] Figure 5 shows what the values ​​along the axis of the colorimeter mean. [Figure 6] Figure 6 shows the results of X-ray diffraction (XRD) analysis of yttria, SPS coating film, Comparative Example 1, and thermal spray coating according to Example 2. [Figure 7] Figure 7 shows scanning electron microscope (SEM) images of the surface of the thermal spray coatings according to Comparative Example 1 and Example 2. [Best Mode for Carrying Out the Invention]

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as they are commonly understood by experts skilled in the art to which this invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

[0043] Throughout this specification, when a part is said to "include" a component, this means, unless otherwise stated, that it may include other components rather than excluding them.

[0044] Semiconductor manufacturing processes utilize equipment such as gate etching equipment, insulating film etching equipment, resist film etching equipment, sputtering equipment, and CVD equipment. Meanwhile, liquid crystal manufacturing processes employ etching equipment for forming thin-film transistors. Furthermore, these manufacturing devices often incorporate plasma generation mechanisms for the purpose of achieving high integration through microfabrication.

[0045] In these manufacturing processes, halogen-based corrosive gases such as fluorine-based and chlorine-based gases are used as processing gases in the aforementioned equipment due to their high reactivity. Examples of fluorine-based gases include SF6, CF4, CHF3, ClF3, HF, and NF3, while examples of chlorine-based gases include Cl2, BCl3, HCl, CCl4, and SiCl4. When microwaves or high-frequency waves are introduced into an atmosphere containing these gases, the gases are converted into plasma. Equipment components exposed to these halogen-based gases or their plasma are required to have very little metal other than the material components on their surface and to possess high corrosion resistance.

[0046] Therefore, the present invention aims to provide a method for manufacturing a thermal spray coating with excellent plasma resistance for covering components for plasma etching equipment.

[0047] The present invention relates to a method for producing an yttria thermal spray coating, characterized in that a spray unit is placed at a distance of 50 to 200 mm from the substrate, Y2O3 thermal spray powder is sprayed using atmospheric plasma to form an yttria thermal spray coating on the substrate, and water is supplied together with the Y2O3 thermal spray powder at a rate of 50 to 400 ml / min.

[0048] In the atmospheric plasma spraying method for manufacturing the thermal spray coating of the present invention, there is a method of coating by reducing the distance between the base material (object to be coated) and the plasma unit in order to form a high-density coating layer.

[0049] However, the short separation distance reduces the travel distance of the molten spray powder, causing deoxidation. This results in the surface of the sprayed coating turning black, and the unusual color makes it difficult to distinguish from contaminants after use in the semiconductor process. This makes it difficult to predict when cleaning and recoating cycles will occur, and the color change of the sprayed coating necessitates altering the emissivity and changing the semiconductor process conditions.

[0050] Therefore, the method for producing an yttria thermal spray coating according to the present invention involves arranging the spray unit at a relatively close distance (50-130 mm) on the substrate, and simultaneously supplying water (distilled water) at a rate of 50-400 ml / min together with Y2O3 thermal spray powder to prevent deoxidation of the yttria component, thereby forming a dense yttria thermal spray coating with low porosity.

[0051] The spray gun in the atmospheric plasma spray coating melts the coating material using a plasma flame and sprays the molten coating material onto the substrate. For example, the plasma flame may be formed by the dissociation of a portion of a plasma gas containing argon (Ar), nitrogen (N2), hydrogen (H2), helium (He), etc.

[0052] In the atmospheric plasma spray coating, the spray process variables are preferably an inert gas flow rate of 320 to 420 SCFH, a nitrogen gas flow rate of 120 to 160 SCFH, and a hydrogen gas flow rate of 120 to 160 SCFH.

[0053] Furthermore, the atmospheric plasma spray coating preferably has a plasma generation current of 360 to 460 A, and more preferably 380 to 440 A.

[0054] In the plasma spray coating, the spray unit is preferably positioned at a distance of 50 to 130 mm from the substrate, and more preferably at a distance of 80 to 120 mm from the substrate.

[0055] If the distance between the spray unit and the substrate surface is less than approximately 50 mm, the distance between the substrate and the plasma is too close, causing deformation of the base material and creating a risk of peeling of the coating layer due to the large amount of thermal energy. If the distance is greater than 130 mm, as the flight distance of the yttria powder increases, the molten granular powder that reaches the substrate solidifies, reducing its kinetic energy and forming pores within the film, resulting in the formation of a less dense coating.

[0056] Here, by supplying water together with the Y2O3 thermal spray powder to prevent the deoxidation of the yttria component, a whitened yttria thermal spray coating can be formed.

[0057] At this time, water (distilled water) can be supplied together with the Y2O3 thermal spray powder at a rate of 50 to 400 ml / min, preferably at a rate of 200 to 350 ml / min.

[0058] Furthermore, as an example, the position where the water is supplied can be at a distance of 2:8 to 8:2 between the plasma forming nozzle and the substrate, and preferably, the position where the water is supplied can be at a distance of 3:7 to 5:5 between the plasma forming nozzle and the substrate.

[0059] In one embodiment, when the distance between the plasma forming nozzle and the substrate surface is 100 mm, the water can be supplied from 20 to 80 mm from the plasma forming nozzle, preferably from 30 to 50 mm from the plasma forming nozzle.

[0060] In one embodiment, when the distance between the plasma forming nozzle and the substrate surface is 50 mm, the water can be supplied from 10 to 40 mm from the plasma forming nozzle, preferably from 15 to 25 mm from the plasma forming nozzle.

[0061] Furthermore, in one embodiment, the water supply location can be 25 to 50 mm from the plasma forming nozzle, and preferably, the water supply location can be 35 to 45 mm from the plasma forming nozzle.

[0062] Furthermore, the multiple water supply nozzles from which the water is supplied may be arranged irregularly or regularly. For example, four water supply nozzles may be arranged at 90° intervals from each other, supplying water from four directions. Preferably, as shown in Figure 1 below, eight water supply nozzles from which the water is supplied are arranged at 45° intervals from each other, supplying water from eight directions to evenly supply water (distilled water) to the Y2O3 thermal spray powder, effectively preventing the deoxidation of yttria.

[0063] Furthermore, as an example, the orifice used in the water supply nozzle may have any shape, but it is preferable to use a circular orifice, and although the size of the orifice is not limited, it is preferable to be 0.007 to 0.011 inches (in).

[0064] In the plasma spray coating method described above, the yttria spray coating is preferably formed to a thickness of 50 to 500 μm, and more preferably to a thickness of 100 to 300 μm.

[0065] In this case, the average particle size of the Y2O3 thermal spray powder is preferably 5 to 60 μm, more preferably 10 to 40 μm, and more preferably 15 to 30 μm.

[0066] If the size of the Y2O3 spray powder is less than 5 μm, the fluidity of the powder during spray coating is low, making it impossible to achieve a uniform film. The powder may oxidize before it is transferred to the flame, or it may not be transferred to the center of the flame at all. This makes it difficult to meet the droplet flight velocity and heat requirements necessary to form a dense film, resulting in a film with high pore size or low hardness. If the average diameter of the Y2O3 spray powder exceeds 60 μm, the molten specific surface area of ​​the granular powder decreases, preventing complete melting. This results in unmelted portions within the coating film, making it difficult to satisfy the quality requirements of the sprayed film as described in this invention.

[0067] Furthermore, the substrate to which the thermal spray coating is applied in the present invention is not particularly limited. For example, the material and shape of the substrate are not particularly limited, as long as it contains a material that can be provided for thermal spraying of such thermal spraying material and have the desired resistance. The material constituting such a thermal sprayed substrate is preferably selected from at least one combination of aluminum, nickel, chromium, zinc and their alloys, alumina, aluminum nitride, silicon nitride, silicon carbide and quartz glass, which are used to make up components for semiconductor manufacturing equipment, etc.

[0068] Such substrates may, for example, be components of semiconductor device manufacturing equipment, and may be components exposed to highly reactive oxygen gas plasma or halogen gas plasma.

[0069] The substrate surface is preferably treated in accordance with the ceramics thermal spraying work standards specified in JIS H9302 before plasma spraying. For example, after removing rust, oils, etc. from the substrate surface, abrasive particles such as Al2O3 and SiC are sprayed to roughen the surface and pre-treat it to a state where thermal spray granule powder can easily adhere.

[0070] Conventional yttria thermal spray coatings result in high porosity within the coating layer. In contrast, the present invention involves positioning a spray unit at a distance of 50 to 130 mm from the substrate, and using atmospheric plasma spraying to form a high-density yttria thermal spray coating on the substrate. Furthermore, water is supplied at a rate of 50 to 400 ml / min from a plasma forming nozzle at a distance of 25 to 50 mm along with the Y2O3 thermal spray powder to suppress the deoxidation of yttria over a short distance, resulting in the production of a whitened, high-density yttria thermal spray coating.

[0071] Therefore, the yttria thermal spray coating produced by the above method has a superior porosity level compared to existing thermal spray coatings, and when applied to semiconductor chambers used in existing etching processes, it exhibits excellent durability and suppresses the phenomenon of coating delamination due to etching gas.

[0072] As an example, the colorimeter measurement value L of the yttria thermal spray coating formed by the method for manufacturing the yttria thermal spray coating described above may be 85 or higher.

[0073] As another example, the yttria thermal spray coating formed by the method for producing the yttria thermal spray coating may have a porosity of less than 2.6%, preferably less than 1.5%, and more preferably less than 1%.

[0074] The present invention will be described in more detail below with reference to examples. However, the following examples are merely illustrative of the present invention and the present invention is not limited to the following examples.

[0075] Comparative Examples 1-2 and Examples 1-2 Using the aforementioned Y2O3 thermal spray material and a plasma gun, plasma was generated at a power of 80-120 kW while moving the spray gun with argon, nitrogen, and hydrogen gases as heat source gases. The generated plasma was used to melt the raw material powder and form a coating film on the base material. The coating film was formed to a thickness of 150-250 μm, and the experimental conditions are shown in Table 1 below. Figure 2 shows a CCD image of the surface of the manufactured thermal spray film, and Figures 3 and 4 show scanning electron microscope images of the side surface of the manufactured thermal spray film. [Table 1]

[0076] Experimental Example 1: Observation of Thermal Spray Coating Figures 3 and 4 below are scanning electron microscope (SEM) images of the surface and side surfaces of the thermal spray coatings according to Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention. The scanning electron microscope (SEM) images of the side surfaces of the thermal spray coatings in Figures 3 and 4 confirm that Example 2 formed a dense thin film with low porosity within the thermal spray coating.

[0077] The porosity was measured as follows: The thermal spray coating was cut perpendicular to the surface of the substrate, the resulting cross-section was embedded in resin and polished, and then an image of the cross-section was taken using an electron microscope (JEOL, JS-6010) (Figures 3 and 4). By analyzing this image using image analysis software (MEDIA CYBERNETICS, Image Pro), the area of ​​the pore portion in the cross-sectional image was identified, and the ratio of the area of ​​such pore portion to the front end surface was calculated. The porosity obtained from the area of ​​pores appearing in the cross-section of the thermal spray coating is shown in Table 1.

[0078] Examples 1 and 2 showed a porosity of less than 2.6%, indicating that the density of the yttria thermal spray coating according to the present invention was increased compared to conventionally used thermal spray coatings. Furthermore, the colorimeter L value was 85 or higher, confirming that a whitened yttria thermal spray coating was formed.

[0079] Experimental Example 2: Crystal Structure Analysis As shown in Figure 6 below, X-ray diffraction (XRD) analysis using a scanning electron microscope (SEM) of the thermal spray coating according to Example 2 confirmed that the SPS vs. cubic crystal structure, known as a high-density coating, is present in a higher proportion than the monoclinic structure.

[0080] Experimental Example 3: Hardness Measurement The "Hardness" column in Table 1 above shows the Vickers hardness measurement results for each thermal spray coating. Vickers hardness is measured using a microhardness tester (company name, model name) with a diamond indenter at a face-to-face angle of 136°, and the Vickers hardness (Hv0.2) obtained when a test force of 294.2 mN is applied.

[0081] As shown in Table 1 above, it was confirmed that the thermal spray coatings of Examples 1 and 2 exhibited a hardness range similar to that of the thermal spray coatings of Comparative Examples 1 and 2.

[0082] Experimental Example 4: Measurement of Surface Roughness The surface roughness (μm) of the coating films produced in Example 2 and Comparative Example 1 of the present invention was measured using a roughness meter (SJ-201), and the results are shown in Figure 7 below.

[0083] As shown in Figure 7 below, when a thermal spray coating was formed using powder of the 10-60 μm level, the thermal spray coating according to Comparative Example 1 showed a surface roughness of 3-6 μm level, while the thermal spray coating according to Example 2 showed a surface roughness of 1-4 μm level. This confirmed that the roughness was reduced by using water.

[0084] Experimental Example 5: Measurement using a thermal spray surface colorimeter Figure 2 below shows surface CCD images of the thermal spray coatings produced by Comparative Examples 1-2 and Examples 1-2 according to the present invention. It was confirmed that Example 2, which used water, showed a white color, compared to Comparative Example 2 and Example 2, which had the same separation distance.

[0085] In Table 1, the columns L, a, and b show the colorimeter measurement results of the thermal spray coating surface. The L value indicates brightness, and a larger value indicates a brighter surface. Of the two comparative examples and example 2, which use water, the L value is large, confirming that it is white.

[0086] Having described in detail certain aspects of the present invention, it will be clear to those with ordinary skill in the art that such specific techniques are merely preferred embodiments and do not limit the scope of the invention. Therefore, the substantial scope of the invention is considered to be defined by the appended claims and their equivalents.

Claims

1. Plasma forming nozzle is positioned at a distance of 50 to 130 mm from the substrate, Y ２ O ３ The thermal spray powder is sprayed with atmospheric plasma to form an yttria thermal spray coating on the substrate, and the Y ２ O ３ A method for producing an yttria thermal spray coating, characterized in that water is supplied together with thermal spray powder at a rate of 50 to 400 ml / min, the water is supplied at a location between the plasma forming nozzle and the substrate, and the ratio of the distance between the water supply location and the plasma forming nozzle to the distance between the water supply location and the substrate is 2:8 to 8:

2.

2. The method for producing an yttria thermal spray coating according to claim 1, characterized in that the atmospheric plasma spraying is performed by arranging the plasma forming nozzle at a distance of 80 to 120 mm from the substrate.

3. The aforementioned Y ２ O ３ A method for producing an yttria thermal spray coating according to claim 1, characterized by supplying water at a rate of 200 to 350 ml / min together with the thermal spray powder.

4. A method for producing an yttria thermal spray coating according to claim 1, characterized in that the ratio of the distance between the water supply location and the plasma forming nozzle to the distance between the water supply location and the substrate is 3:7 to 5:

5.

5. The method for producing an yttria thermal spray coating according to claim 1, characterized in that the position where the water is supplied is 25 to 50 mm from the plasma forming nozzle.

6. The method for manufacturing an yttria thermal spray coating according to claim 1, characterized in that the four water supply nozzles, which supply the water, are arranged at 90° intervals from each other, and water is supplied from four directions.

7. The method for manufacturing an yttria thermal spray coating according to claim 1, characterized in that the eight water supply nozzles, from which the water is supplied, are arranged at 45° intervals from each other, and water is supplied from eight directions.

8. A method for producing an yttria thermal spray coating according to claim 1, characterized in that the orifice used in the nozzle to which the water is supplied is circular, and the size of the orifice is 0.007 to 0.011 inches.

9. The aforementioned Y ２ O ３ A method for producing an yttria thermal spray coating according to claim 1, characterized in that the average particle size of the thermal spray powder is 5 to 60 μm.

10. A method for producing an yttria thermal spray coating according to claim 1, characterized in that the thickness of the yttria thermal spray coating is 100 to 300 μm.

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