Method for producing high density yttria coating by atmospheric plasma spraying and yttria sprayed coating produced 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 thermal spray coating using an atmospheric plasma spraying method for Y2O3 thermal spray powder. [Background technology]

[0002] The importance of plasma dry etching processes is becoming increasingly important in order to perform microfabrication for the high integration of substrate circuits such as silicon wafers in semiconductor manufacturing processes.

[0003] To enable use in such an environment, methods have been proposed to extend the life of components by using materials with excellent plasma resistance for the chamber components or by forming a coating of a material with excellent plasma resistance on the surface of the components.

[0004] Among these, techniques for imparting new functionality by coating the surface of a substrate with various materials have been used in various fields. One known surface coating technique is a thermal spraying method in which thermal spray particles made of a material such as ceramics are sprayed onto the surface of a substrate in a softened or molten state by combustion or electrical energy to form a thermal spray coating.

[0005] In general, thermal spray coating is performed by heating and melting fine powder and spraying the molten powder onto the coating surface of the base material. The sprayed molten powder is rapidly cooled and solidifies, and is then deposited on the coating surface mainly by mechanical bonding forces.

[0006] Among the thermal spray coating methods, plasma spray coating, which uses a high-temperature plasma flame to melt the powder, is always used to coat ceramics and metals with high melting points, such as tungsten and molybdenum. Thermal spray coating is advantageous for producing high-performance materials that exhibit wear resistance, corrosion resistance, heat resistance and thermal barrier properties, superhardness, oxidation resistance, insulation, friction properties, heat dissipation, biofunctional properties, and radiation resistance by utilizing the material properties of the base material. Compared to other coating methods such as chemical vapor deposition and physical vapor deposition, plasma spray coating can quickly coat large areas of target objects.

[0007] In the field of semiconductor device manufacturing, microfabrication of the surface of a semiconductor substrate is generally performed by dry etching using plasma of a halogen-based gas such as fluorine, chlorine, or bromine. After dry etching, the interior of the chamber (vacuum vessel) from which the semiconductor substrate is removed is cleaned using oxygen gas plasma. During this process, components exposed to the highly reactive oxygen gas plasma or halogen gas plasma inside the chamber may corrode. When corroded (eroded) parts fall off from the components in the form of particles, these particles can adhere to the semiconductor substrate and become foreign matter (hereinafter, the foreign matter is referred to as a particle) that can cause defects in the circuit.

[0008] Therefore, in semiconductor device manufacturing equipment, it has been common to provide a ceramic thermal spray coating with plasma erosion resistance on components exposed to plasma of oxygen gas, halogen gas, or the like in order to reduce particle generation.

[0009] Factors that cause the generation of these particles include the peeling of reaction products that have adhered to the inside of the vacuum chamber, as well as deterioration of the chamber due to the use of halogen gas plasma or oxygen gas plasma. Furthermore, according to the studies of the present inventors, it is known that the number and size of particles generated from a thermal spray coating in a dry etching environment are caused by the strength of the bonding force between the particles that make up the thermal spray coating, the presence of unmelted particles, or high porosity.

[0010] In particular, the higher the density inside the ceramic spray coating, the less CFx-based process gas is adsorbed by defects such as pores during the dry etching process, reducing etching caused by plasma ion collisions.

[0011] Generally, the coating method used to form high-density sprayed coatings is the suspension plasma spray (SPS), but the SPS method has the disadvantage of being more complicated to manufacture and more expensive than the air plasma spray (APS) method.

[0012] Suspension plasma spraying (SPS) technology involves high process temperatures during coating inside the semiconductor chamber due to a relatively high heat source, which can cause problems such as product deformation, and as the particle size decreases, the particle flight distance becomes shorter, which reduces the working distance between the plasma equipment and the substrate to be coated, limiting the workability. In addition, SPS technology is in a suspension state where water and particles are dispersed, so the coating deposition rate is slow when the same volume is injected, resulting in additional process time and high manufacturing costs.

[0013] In addition, as semiconductor process conditions become stricter, RF plasma high-power devices are required to form stable thick films of 150 μm or more. However, when SPS technology is used to form films thicker than 150 μm, internal cracks and peeling due to residual stress occur, and there are technical limitations to achieving coating thicknesses of several hundred μm.

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

[0015] The powder of the thermal spray material used in the typical APS thermal spraying method consists of primary particles on the order of a few microns that gather together to form granular powder of 20 to 40 microns, but a method has been proposed to increase the density of the thermal spray coating by reducing the primary powder that makes up this thermal spray material to 1 micron or less. However, with this method, as the specific surface area of ​​the granular powder increases, heat is not transferred uniformly to the primary powder inside the particles, and a coating containing unmelted or remelted states is formed on the surface or inside of the thermal spray coating, which acts as a cause of particle generation during the dry etching process.

[0016] Furthermore, if the secondary particles formed from the granular powder are too small, the particles will be bound together by electrostatic attraction between the granular powder particles, making it practically difficult to transport them in the atmosphere, or the low particle mass of the particles after transport makes it impossible for them to be transported to the central frame, and they are likely to scatter to other locations.

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

[0018] However, the short separation distance shortens the travel distance of the molten thermal spray powder, causing deoxidation, which turns the surface of the thermal spray coating black in part or entirely. This different coating color from conventional coatings can cause the following problems:

[0019] If the thermal spray coating is black, it is difficult to distinguish it from contaminants after use in semiconductor processes, making it difficult to predict when cleaning and recoating cycles will be required. In addition, color changes in the thermal spray coating cause problems such as changing the emissivity and having to change the semiconductor process conditions.

[0020] To solve these problems, it is possible to restore the white surface of the thermal spray coating by heat treating the blackened thermal spray coating in an atmospheric (oxygen-containing) atmosphere, but the additional heat treatment process reduces the production speed and increases the manufacturing cost. In addition, since many semiconductor chambers are made of metal materials, there is a possibility that the base material may be thermally damaged during the heat treatment process.

[0021] As a conventional technology, the thermal spray material disclosed in Korean Patent Publication No. 10-2016-0131918 (November 16, 2016) contains rare earth oxyhalides (RE-OX) containing rare earth elements (RE), oxygen (O), and halogen elements (X) as constituent elements, and the molar ratio of halogen elements to rare earth elements (X / RE) is 1.1 or more, which improves plasma resistance and shows improvements in properties such as porosity and hardness.

[0022] As described above, in order to overcome the physical property limitations of yttrium oxide thermal spray materials, techniques have been proposed for producing yttrium oxyfluoride thermal spray materials with improved physical properties such as porosity and hardness. However, the reality is that there is a continuing demand from the industrial side for technological development to produce dense thermal spray coatings with improved plasma resistance. Summary of the Invention [Problem to be solved by the invention]

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

[0024] To achieve the above-mentioned object, one embodiment of the present invention provides a method for producing an yttria thermal spray coating, comprising: disposing a spray unit at a distance of 50 to 130 mm from a substrate; atmospheric plasma spraying Y2O3 thermal spray powder to form an yttria thermal spray coating on the substrate; and supplying water at a rate of 50 to 400 ml / min together with the Y2O3 thermal spray powder.

[0025] In a preferred embodiment of the present invention, the atmospheric plasma spraying can be performed by disposing a 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 Y2O3 thermal spraying powder.

[0027] In a preferred embodiment of the present invention, the position where the water is supplied may be at 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 may be such that the distance between the plasma-forming nozzle and the substrate is 3:7 to 5:5.

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

[0030] In a preferred embodiment of the present invention, the four water supply nozzles through which water is supplied are arranged at 90° intervals 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 through which water is supplied are arranged at 45° intervals from one another, 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 may be 0.007 to 0.011 inches.

[0033] In a preferred embodiment of the present invention, the Y2O3 thermal spray powder may have an average particle size of 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] In another preferred embodiment of the present invention, there is provided an yttria thermal sprayed coating formed by the above-described method for producing an yttria thermal sprayed coating.

[0036] In a preferred embodiment of the present invention, the color difference measurement value L of the yttria thermal spray coating may be 85 or more.

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

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

[0039] The yttria thermal spray coating produced by the present invention forms a high-density white thermal spray coating layer of 1.5% or less, reduces the etching rate due to process gas in the dry etching process, has excellent durability when used as a coating material for components inside a semiconductor chamber, and suppresses the phenomenon of coating material detachment due to etching, which can contribute to improving the yield of semiconductor wafers.

[0040] In addition, the method for manufacturing an yttria thermal spray coating according to the present invention whitens the surface of the coating layer during the manufacturing process, thereby providing a reasonable processing time and a high-quality thermal spray coating layer without additional cost increase. [Brief explanation of the drawings]

[0041] [Figure 1]FIG. 1 is a schematic diagram showing the supply of water (distilled water) in the method for producing an yttria thermal spray coating according to the present invention. [Figure 2] FIG. 2 shows scanning electron microscope (SEM) images of the surfaces of thermal spray coatings according to the present invention (a) Comparative Example 1 (b) Comparative Example 2 (c) Example 1 (d) Example 2. [Figure 3] FIG. 3 shows scanning electron microscope (SEM) images at low magnification of the side of the thermal spray coating according to the present invention (a) Comparative Example 1 (b) Comparative Example 2 (c) Example 1 (d) Example 2. [Figure 4] FIG. 4 shows high magnification scanning electron microscope (SEM) images of the side surfaces of thermal spray coatings according to the present invention (a) Comparative Example 1 (b) Comparative Example 2 (c) Example 1 (d) Example 2. [Figure 5] Figure 5 shows what the values ​​along the axes of the color difference meter mean. [Figure 6] FIG. 6 shows the results of X-ray diffraction (XRD) analysis of yttria, the SPS coating film, the thermal spray coatings of Comparative Example 1 and Example 2. [Figure 7] FIG. 7 shows scanning electron microscope (SEM) images of the surfaces of the thermal spray coatings of Comparative Example 1 and Example 2. BEST MODE FOR CARRYING OUT THE INVENTION

[0042] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention belongs. Generally, the nomenclature used herein is that well known and commonly used in the art.

[0043] Throughout this specification, when a part is said to "comprise" certain elements, this means that it may further include other elements, rather than excluding other elements, unless specifically stated to the contrary.

[0044] The semiconductor manufacturing process uses gate etching equipment, insulating film etching equipment, resist film etching equipment, sputtering equipment, CVD equipment, etc. Meanwhile, the liquid crystal manufacturing process uses etching equipment to form thin film transistors, etc. Furthermore, these manufacturing equipment are configured with a plasma generation mechanism 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 process gases in the above-mentioned equipment due to their high reactivity. Fluorine-based gases include SF6, CF4, CHF3, ClF3, HF, and NF3, while chlorine-based gases include Cl2, BCl3, HCl, CCl4, and SiCl4. These gases are converted into plasma when microwaves or high-frequency waves are introduced into the atmosphere containing these gases. Equipment components exposed to these halogen-based gases or their plasma must have very little metal other than the material components on their surfaces, ensuring high corrosion resistance.

[0046] Therefore, an object of the present invention is to provide a method for producing a thermal spray coating having excellent plasma resistance for coating components for plasma etching equipment.

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

[0048] In the atmospheric plasma spraying method for producing the thermal spray coating of the present invention, there is a method in which the base material (object to be coated) and the plasma unit are spaced apart closely to form a high-density coating layer.

[0049] However, due to the short separation distance, the travel distance of the molten thermal spray powder is shortened, causing deoxidation, which turns the surface of the thermal spray coating black. This different coating color is difficult to distinguish from contaminants left after use in semiconductor processes, making it difficult to predict when the cleaning and recoating cycle will arrive. In addition, the color change in the thermal spray coating requires changes to the emissivity and other semiconductor process conditions.

[0050] Therefore, in the method for producing an yttria thermal spray coating according to the present invention, the spray unit is positioned relatively close (50 to 130 mm) above the substrate, and at the same time, water (distilled water) is supplied at a rate of 50 to 400 ml / min together with the Y2O3 thermal spray powder to prevent deoxidation of the yttria component, thereby enabling the formation of 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 a substrate. For example, the plasma flame may be formed by dissociating a portion of a plasma gas, such as argon gas (Ar), nitrogen gas (N), hydrogen gas (H), or helium gas (He).

[0052] The atmospheric plasma spray coating has spray process variables of inert gas flow rate of 320-420 SCFH, nitrogen gas flow rate of 120-160 SCFH, and hydrogen gas flow rate of 120-160 SCFH.

[0053] The atmospheric plasma spray coating may preferably have a plasma generation current of 360 to 460A, more preferably 380 to 440A.

[0054] In the plasma spray coating, the spray unit is preferably positioned at a distance of 50 to 130 mm from the substrate, 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 closer than approximately 50 mm, the distance between the substrate and the plasma is too close, causing deformation of the base material and the risk of peeling off of the coating layer due to the large thermal energy.If the distance is farther than 130 mm, as the flight distance of the yttria powder increases, the molten granular powder that reaches the substrate solidifies more rapidly, reducing kinetic energy and forming pores in the coating, resulting in the formation of a less dense coating.

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

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

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

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

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

[0061] Furthermore, in one embodiment, the position where the water is supplied can be 25 to 50 mm from the plasma generating nozzle, and preferably, the position where the water is supplied can be 35 to 45 mm from the plasma generating nozzle.

[0062] In addition, the plurality of water supply nozzles through 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, and water may be supplied from four directions. Preferably, as shown in FIG. 1 below, eight water supply nozzles through which the water is supplied are arranged at 45° intervals from each other, and water is supplied from eight directions, thereby evenly supplying water (distilled water) to the Y2O3 thermal spray powder and effectively preventing deoxidation of yttria.

[0063] 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 the size of the orifice is not limited, but is preferably 0.007 to 0.011 inches (in).

[0064] In the plasma spray coating method, 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 spraying powder is preferably 5 to 60 μm, more preferably 10 to 40 μm, and even more preferably 15 to 30 μm.

[0066] If the size of the Y2O3 thermal spray powder is less than 5 μm, the powder will have low fluidity during thermal spray coating, making it impossible to achieve a uniform film, and the powder will oxidize before being delivered to the flame or will not be delivered to the center of the flame, making it difficult to meet the droplet flight speed and heat quantity required to form a dense film, resulting in a film with high porosity or low hardness.If the average diameter of the Y2O3 thermal spray powder exceeds 60 μm, the melting specific surface area of ​​the granular powder will decrease, preventing complete melting and leaving unmelted areas in the coating film, making it difficult to meet the thermal spray coating quality required in the present invention.

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

[0068] Such a substrate may be, for example, a component of a semiconductor device manufacturing apparatus, and may be a component exposed to highly reactive oxygen gas plasma or halogen gas plasma.

[0069] Prior to plasma spraying, the substrate surface is preferably treated in accordance with the ceramic thermal spraying standards specified in JISH 9302. For example, after removing rust, oils, grease, etc. from the substrate surface, abrasive particles such as Al2O3, SiC, etc. are sprayed onto the surface to roughen it and pretreat it to a state where the spray granule powder can easily adhere.

[0070] While conventional yttria sprayed coatings result in high porosity within the coating layer, in the present invention, a spray unit is positioned 50 to 130 mm above the substrate, and Y2O3 spray powder is atmospheric plasma sprayed to form a high-density yttria sprayed coating on the substrate. In addition, water is supplied at a rate of 50 to 400 ml / min at a position 25 to 50 mm from the plasma generating nozzle along with the Y2O3 spray powder, thereby suppressing deoxidation of the yttria over a short distance, resulting in the production of a white, high-density yttria sprayed coating.

[0071] Therefore, the yttria thermal spray coating manufactured by this method has a superior porosity level compared to existing thermal spray coatings, is applicable to semiconductor chambers used in existing etching processes, exhibits excellent durability, and suppresses the phenomenon of coating detachment due to etching gas.

[0072] As an example, the color difference meter measurement value L of the yttria thermal spray coating formed by the method for producing the yttria thermal spray coating may be 85 or more.

[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 are not intended to limit the scope of the present invention.

[0075] Comparative Examples 1-2 and Examples 1-2 Using the Y2O3 thermal spray material and a plasma gun, argon, nitrogen, and hydrogen gases were flowed as heat source gases, and plasma was generated at a power of 80 to 120 kW while the thermal spray gun was moved. The raw material powder was melted using the generated plasma to form a coating on the base material. The coating thickness was 150 to 250 μm, and the experimental conditions are shown in Table 1 below. A CCD image of the surface of the produced thermal spray coating is shown in Figure 2, and scanning electron microscope images of the side of the produced thermal spray coating are shown in Figures 3 and 4. [Table 1]

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

[0077] The porosity was measured as follows: The thermal spray coating was cut into a plane perpendicular to the surface of the substrate, the resulting cross section was embedded in resin, polished, and then a cross-sectional image was taken using an electron microscope (JEOL, JS-6010) (Figures 3 and 4). This image was analyzed using image analysis software (MEDIA CYBERNETICS, Image Pro) to identify the area of ​​the pores in the cross-sectional image, and the proportion of the area of ​​these pores to the front end face was calculated. The porosity obtained from the area of ​​the pores that appeared in the cross section of the thermal spray coating is shown in Table 1.

[0078] Examples 1 and 2 showed porosities of less than 2.6%, indicating that the density of the yttria thermal spray coating according to the present invention was increased compared to thermal spray coatings produced by conventional methods. Furthermore, the color difference meter L value was 85 or more, 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) confirmed that the thermal spray coating of Example 2 contained a high proportion of SPS cubic crystal structure, known as a high-density coating, compared to the monoclinic structure.

[0080] Experimental example 3: Hardness measurement The "Hardness" column in Table 1 shows the results of measuring the Vickers hardness of each thermal spray coating. The Vickers hardness was measured using a microhardness tester (company name, model name) and was measured as a Vickers hardness (Hv0.2) when a test force of 294.2 mN was applied using a diamond indenter with a facing angle of 136°.

[0081] As shown in Table 1 above, it was confirmed that the thermal spray coatings of Examples 1 and 2 exhibited hardness in the same range as 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 prepared in Example 2 of the present invention and Comparative Example 1 was measured using a roughness tester (SJ-201), and the results are shown in FIG.

[0083] As shown in Figure 7 below, when a thermal spray coating was formed using powder with a particle size of 10 to 60 μm, the thermal spray coating of Comparative Example 1 exhibited a surface roughness of 3 to 6 μm, whereas the thermal spray coating of Example 2 exhibited a surface roughness of 1 to 4 μm. This confirmed that the use of water reduced the roughness.

[0084] Experimental example 5: Thermal spray surface color difference measurement Figure 2 below shows surface CCD images of the thermal spray coatings from Comparative Examples 1-2 and Examples 1-2 according to the present invention, and it was confirmed that, among Comparative Example 2 and Example 2, which were separated at the same distance, Example 2, which used water, showed a white color.

[0085] In Table 1, the columns L, a, and b show the results of measuring the thermal spray coating surface with a color difference meter. The L value indicates brightness, with a larger value indicating a brighter color. It was confirmed that Example 2, which used water and Comparative Example 2, which were separated at the same distance, showed a larger value and therefore indicated a white color.

[0086] While the specific details of the present invention have been described above, it will be apparent to those skilled in the art that these specific details are merely preferred embodiments and are not intended to limit the scope of the present invention. Therefore, the true scope of the present invention is considered to be defined by the appended claims and their equivalents.

Claims

1. The spray unit was placed at a distance of 50 to 130 mm above the substrate. ２ O ３ The thermal spray powder is atmospheric plasma sprayed to form an yttria thermal spray coating on a substrate, ２ O ３ A method for producing an yttria thermal spray coating, comprising supplying water at a rate of 50 to 400 ml / min together with the thermal spray powder.

2. 2. The method for producing a yttria thermal spray coating according to claim 1, wherein the atmospheric plasma spraying is performed by positioning a spray unit at a distance of 80 to 120 mm from the substrate.

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

4. 2. The method for producing a thermally sprayed yttria coating according to claim 1, wherein the water is supplied to a position where the distance between the plasma generating nozzle and the substrate is 2:8 to 8:

2.

5. 5. The method for producing a thermally sprayed yttria coating according to claim 4, wherein the distance between the plasma generating nozzle and the substrate at the position where the water is supplied is 3:7 to 5:

5.

6. 2. The method for producing an yttria thermal spray coating according to claim 1, wherein the position where the water is supplied is 25 to 50 mm from the plasma generating nozzle.

7. 2. The method for producing an yttria thermal spray coating according to claim 1, wherein the four water supply nozzles through which water is supplied are arranged at 90° intervals from each other, and water is supplied from four directions.

8. 2. The method for producing a yttria thermal spray coating according to claim 1, wherein the eight water supply nozzles from which water is supplied are arranged at 45° intervals from one another, and water is supplied from eight directions.

9. 2. The method for producing a yttria thermal spray coating according to claim 1, wherein the orifice used in the water supply nozzle is circular, and the size of the orifice is 0.007 to 0.011 inches.

10. The Y ２ O ３ 2. The method for producing an yttria thermal spray coating according to claim 1, wherein the thermal spray powder has an average particle size of 5 to 60 μm.

11. 2. The method for producing a thermal sprayed yttria coating according to claim 1, wherein the thickness of the thermal sprayed yttria coating is 100 to 300 μm.

12. An yttria thermal sprayed coating formed by the method for producing an yttria thermal sprayed coating according to any one of claims 1 to 11.

13. The yttria thermal spray coating according to claim 12, wherein the color difference meter measurement value L of the yttria thermal spray coating is 85 or more.

14. The yttria thermal spray coating according to claim 12, wherein the porosity of the yttria thermal spray coating is less than 2.6%.

15. The yttria thermal spray coating according to claim 12, wherein the porosity of the yttria thermal spray coating is less than 1.0%.

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