Plasma thermal spray coating film, method for producing same, and plasma resistant member

Abstract

The present invention relates to a plasma thermal spray coating, a method for manufacturing the same, and a plasma resistant member. The present invention provides a method for preparing a plasma thermal spray coating, comprising the steps of: providing a particle powder containing yttrium aluminum garnet crystals; a step of forming a plasma flow from the plasma thermal spray torch toward the base material; a step of supplying the particulate powder to the plasma stream to form molten droplets of the particulate powder; a step of providing a coolant flow in a direction intersecting the plasma flow containing the molten droplets; and a step of supplying a plasma flow passing through the coolant flow to the thermal spray base material to form a thermal spray coating including a crystalline phase and an amorphous phase.

Description

Technical Field

[0001] The present invention relates to a plasma thermal spray coating and a method for preparing the same, and a plasma-resistant component, and more particularly to a plasma thermal spray coating containing yttrium aluminate with high crystallinity and a method for preparing the same. Background Art

[0002] Recently, the high integration and ultra-fine line width technology of semiconductor processes require plasma etching processes under ultra-extreme environments such as high-density plasma, high cleanliness, excessive electrical shock, etc. In particular, the plasma etching process using reactive gas containing halogen elements such as F, Cl or Br with strong chemical reactivity, while etching various deposited materials on the surface of the wafer, chemically and physically reacts with metal or ceramic parts inside the chamber, causing damage to the surface of the parts and generating non-volatile contamination particles.

[0003] Three-dimensional multi-layer stacking methods for high integration of more than 100 layers are being applied to the preparation of three-dimensional V-NAND flash memory. To this end, dry etching processes are continuously developed to prepare complex three-dimensional structures with high aspect ratio contacts (HARC), and etching, cleaning and deposition processes are repeatedly performed in the chamber.

[0004] Gas types used in the etching process include CF 4 , CCl 4 NF 3 , HBr, SF 6 , Cl 2 These process gases are plasmatized to etch the wafer and the components constituting the chamber, thereby causing a decrease in productivity, such as a decrease in yield due to particle generation and a shortened preventive maintenance (PM) cycle.

[0005] To prevent this, a method using Y 2 O 3 , YF 3 , Y x O y F z There is a method of thermally spraying various materials such as yttrium aluminum garnet (YAG) on various components in the chamber, but this method has several problems.

[0006] Etching mechanisms include chemical etching by plasma ions and physical etching by ion bombardment. Therefore, the thermal spray coating film applied to the inside of the chamber must ensure resistance to chemical etching and physical etching. 2 O 3 Although it has the advantages of relatively high hardness and low preparation cost, due to the presence of F - Ions and aging time (Seasoning Time) occurs at the beginning of the process, and Y x O y F z and YF 3 Although F - Ions have excellent resistance, but due to the low hardness of the material itself, there is a problem of low resistance to physical etching.

[0007] Recently, for the purpose of high aspect ratio (HARC), in order to maximize the anisotropic etching effect of Br ions, a mixture of HBr gas and Cl 2 and / or 2 Gases, but it is known that YAG (Yttrium Aluminum Garnet) material, which has very high hardness and excellent resistance to hydrogen embrittlement, is suitable for use in etching processes using these process gases.

[0008] However, when the YAG material is formed into a film using a conventional thermal spray coating method, the YAG material is placed in a quenching environment after melting and is formed into a film in an amorphous state, which makes it difficult to obtain the desired level of physical property values. In addition, the crystallization temperature of YAG is above 900°C, so it is actually impossible to crystallize the film-forming thermal spray coating component through a heat treatment process. On the other hand, if the plasma output is reduced during the thermal spray coating process, the crystallinity may increase slightly, but the physical property values ​​of the film-forming thermal spray coating decrease and the porosity increases, so this cannot be said to be a fundamental solution.

[0009] Therefore, there is a need for a coating process that can minimize the quenching effect that occurs in conventional thermal spray coating processes while improving physical properties such as high density.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: KR No. 2019-0017333A

[0013] Patent Document 2: KR No. 2019-0082119A

[0014] Patent Document 3: JP No. 6918996B

[0015] Patent Document 4: JP No. 7035293B Summary of the invention

[0016] Problem that the invention aims to solve

[0017] In order to solve the problems of the conventional technology, an object of the present invention is to provide a thermal spray coating method capable of improving physical properties by increasing the density of a yttrium aluminate thermal spray coating film.

[0018] Another object of the present invention is to provide a thermal spray coating method capable of improving physical properties by increasing the density of a yttrium aluminate thermal spray coating film without requiring a recrystallization step.

[0019] Another object of the present invention is to provide a thermal spray coating film containing yttrium aluminate having a high crystallization rate and a plasma-resistant component including the same.

[0020] Means used to solve problems

[0021] In order to solve the technical problem, the present invention provides a method for preparing a plasma thermal spray coating, which is a plasma thermal spraying method for a thermal spray coating containing YAG, comprising the following steps: providing a granular powder containing YAG crystals; forming a plasma flow from a plasma thermal spray torch to a base material; supplying the granular powder to the plasma flow to form molten droplets of the granular powder; providing a coolant flow in a direction intersecting the plasma flow containing the molten droplets; and providing a plasma flow through the coolant flow to the thermal spray base material to form a thermal spray coating containing a crystalline phase and a non-crystalline phase.

[0022] In the present invention, the step of forming molten droplets may include the step of partially melting the granular powder in a state where YAG crystals are contained inside the molten droplets.

[0023] In the present invention, the D50 of the particle powder may be 15 μm to 75 μm.

[0024] In the present invention, the D50 of the particle powder may be 15 μm to 45 μm.

[0025] In the present invention, the thermal spray coating preferably has a crystallinity of 45% or more.

[0026] Furthermore, the porosity of the thermal spray coating is preferably 1% to 3.1%.

[0027] In the present invention, the coolant flow may contain water.

[0028] In the present invention, the distance between the plasma torch and the base material is preferably 80 mm to 160 mm.

[0029] In the present invention, a coolant injector for supplying the coolant flow is included, and the coolant injector is preferably in a ring shape surrounding the plasma flow.

[0030] In the present invention, the coolant injector may be provided on an inner surface thereof with a plurality of injection holes directed toward the plasma flow.

[0031] In the present invention, the flow rate of the coolant stream is preferably 100 ml / min to 500 ml / min.

[0032] In the present invention, the Vickers hardness of the amorphous phase is preferably 700 to 800.

[0033] Furthermore, in the present invention, the Vickers hardness of the crystal phase may be 1000 to 1110.

[0034] In addition, the Vickers hardness of the crystalline phase relative to the Vickers hardness of the amorphous phase may be 1.3 to 1.6.

[0035] In order to solve the other technical problem, the present invention provides a plasma thermal spray coating, which is a thermal spray coating containing Y-Al-O, wherein the Y-Al-O in the thermal spray coating includes a crystalline phase and an amorphous phase, the crystalline phase includes YAG, and the Vickers hardness (Hv) of the crystalline phase is greater than 1000.

[0036] In the present invention, the ratio of the Vickers hardness of the crystalline phase to the Vickers hardness of the amorphous phase is preferably 1.3 or more.

[0037] In the present invention, the crystallinity of the YAG calculated from the XRD spectrum of the YAG is preferably 45% or more.

[0038] In the present invention, the cross section of the thermal spray coating includes a bright region representing the crystal phase in an optical microscope image, and the average area of ​​the region is preferably 100 μm 2 above.

[0039] Furthermore, the present invention provides a plasma-resistant component, comprising: a base material; and the thermal spray coating formed on the base material.

[0040] Effects of the Invention

[0041] According to the present invention, a thermal spray coating method can be provided which can improve physical properties by increasing the density of a yttrium aluminate thermal spray coating film.

[0042] Furthermore, according to the present invention, it is possible to provide a thermal spray coating method capable of improving physical properties by increasing the density of a yttrium aluminate thermal spray coating film without requiring a recrystallization process.

[0043] Furthermore, according to the present invention, a thermal spray coating film containing yttrium aluminate having a high crystallization rate can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 FIG. 1 is a diagram schematically showing a plasma thermal spraying device according to an embodiment of the present invention.

[0045] Figure 2 yes Figure 1 An exemplary top view of a coolant injector.

[0046] Figure 3 The following is a scanning electron microscope (SEM) photograph of a particle powder sample prepared in the present invention.

[0047] Figure 4 Parts (a) to (f) are electron microscope photographs taken after grinding the cross sections of the base materials of Examples 1 to 6, respectively.

[0048] Figure 5 Parts (a) to (g) are electron microscope photographs taken after grinding the cross sections of the base materials of Comparative Examples 1 to 7.

[0049] Figure 6 Parts (a) and (b) are optical microscope photographs of the cross section and the surface of the film of Example 1, respectively.

[0050] Figure 7 Parts (a) and (b) are optical microscope photographs of the cross section and the surface of the film of Comparative Example 3, respectively.

[0051] Figure 8 Parts (a) and (b) are optical microscope photographs of the surfaces of the films of Comparative Examples 1 and 2, respectively.

[0052] Fig. 9 Parts (a) to (d) are photographs showing the results of X-ray diffraction (XRD) analysis of plasma thermal sprayed films formed in Comparative Example 1, Comparative Example 2, Example 1, and Example 2, respectively.

[0053] Fig.10 It shows that Fig. 9 A graph showing the results of XRD peak indexing for a portion of the spectrum.

[0054] Description of Reference Numerals

[0055] 10: Thermal spray components

[0056] 12: Base material

[0057] 14: Thermal spray coating

[0058] 100: Plasma thermal spraying device

[0059] 110: Plasma torch

[0060] 120: Powder syringe

[0061] 130: Coolant injector

[0062] 140: stage DETAILED DESCRIPTION

[0063] Unless otherwise defined, all technical terms and scientific terms used in this specification have the same meanings as those commonly understood by those of ordinary skill in the art to which the invention belongs. Generally speaking, the nomenclature used in this specification is well known and commonly used in the art.

[0064] Throughout the specification, unless explicitly stated otherwise, a part “comprising” a certain constituent element means that other constituent elements may also be included, rather than excluding other constituent elements.

[0065] Figure 1 Schematically shows a plasma thermal spraying device according to an embodiment of the present invention. Hereinafter, the preparation process of the present invention will be described with reference thereto.

[0066] Reference Figure 1 The plasma thermal spraying device 100 includes a plasma torch 110 or a plasma gun, a powder injector 120, and a coolant injector 130. In addition, the device may be provided with a table 140 for placing a base material 12 for forming a film.

[0067] In the present invention, the base material may be any material, for example, aluminum, stainless steel, yttrium oxide, aluminum oxide, quartz, etc. may be used.

[0068] In the present invention, the spacing distance between the plasma torch and the base material can be appropriately set. In the present invention, the spacing distance refers to the distance from the nozzle 112 of the plasma torch to the surface of the base material 12, preferably maintained in the range of 80 mm to 160 mm, so that the yield can be improved by providing molten powder droplets without loss. If the spacing distance is less than 80 mm, the problem of reducing the crystallization rate due to the excessively high droplet temperature occurs, and if it exceeds 160 mm, there is a problem of a sharp deterioration of the physical properties of the resulting film.

[0069] The plasma torch 110 generates an arc discharge between the cathode and the anode while causing a large amount of gas to flow out, thereby ejecting plasma in a jet state. The plasma ejected from the plasma torch forms a plasma stream toward the base material. When the raw material powder is added to the plasma stream, the raw material powder can be melted in a short time. At this time, the situation in which the plasma thermal spraying device generates a plasma jet in an open state in the atmosphere is called atmospheric plasma spraying technology, and the present invention can be applied to atmospheric plasma spraying technology.

[0070] In the present invention, the powder injector 120 supplies raw material powder as a material for the thermal spray coating. In the present invention, the raw material powder may include yttrium aluminum oxide represented by Y-Al-O and its precursor. In the present invention, the yttrium aluminum oxide may be YAG, YAM or YAP. Exemplarily, the raw material powder may be YAG (Y 3 Al 5 O 12 ) or YAG precursor.

[0071] In the present invention, it is possible to use a YAG (Y 3 Al 5 O 12 ) as the YAG precursor. For example, the YAG precursor may be Al 2 O 3 and Y 2 O 3 In addition, the YAG precursor may include a mixture of Al 2 O 3 and Y 2 O 3 For example, in addition to YAG (Y 3 Al 5 O 12 ), it may also include Al and Y in a molar ratio of 1:4. 2 Al 8 O15 , YAlO with a molar ratio of Al to Y of 1:1 3 , Al and Y in a molar ratio of 4:2 4 Al 2 O 9 , Al and Y in a molar ratio of 4:1 8 Al 2 O 18 In addition to the intermediate compounds exemplified, compounds having different molar ratios may also be included. These intermediate compounds may be prepared by mixing with Al 2 O 3 The powders are mixed to be used as mixed powder.

[0072] In the present invention, the raw material powder may be a powder molded in a particle shape. For example, the raw material powder may be a molded body obtained by spray drying YAG powder. In addition, the raw material powder may be prepared by heat treating or plasma treating the spray dried molded body to melt a portion of it.

[0073] In the present invention, the raw material powder may contain an additional powder component in addition to YAG or a YAG precursor. In this case, a composite film containing an yttrium aluminate phase other than YAG can of course be formed.

[0074] The device of the present invention includes a coolant injector 130. The coolant injector 130 injects a coolant. In the present invention, water is used as the coolant, preferably deionized water.

[0075] In the present invention, preferably, the coolant injector 130 is disposed at the rear end of the powder injector 120 on the path of the plasma flow.

[0076] In the present invention, the coolant injector 130 is preferably spaced 20 mm to 50 mm from the plasma nozzle. If the distance is too short, the powder injector may be interfered with, and if the distance exceeds 50 mm, the droplet cooling and powder particle size filtering effects may be reduced.

[0077] The interval between the powder injector 120 and the coolant injector 130 may be appropriately designed in consideration of the melting degree of the supplied powder or the cooling degree by the coolant, and the plasma thermal spraying device 100 may be provided with an adjustment mechanism for adjusting the configuration position of the coolant injector 130 .

[0078] Figure 2 yes Figure 1 An exemplary top view of a coolant injector. Figure 2 The coolant injector is shown viewed from the axial direction of the plasma flow.

[0079] Reference Figure 2 , the coolant injector 130 includes a coolant flow path 132 and a plurality of coolant injection holes (orifice) 134 attached to the coolant flow path. Exemplarily, the shape of the coolant flow path 132 is not particularly limited. For example, as shown in the figure, the flow path can be annular, and a plurality of injection holes 134 can be arranged along the inner surface of the annular coolant flow path. In the present invention, the number of the injection holes 134 can be appropriately set, and as shown in the figure, for example, eight holes can be arranged at equal angles toward the center of the coolant flow path.

[0080] In the present invention, the size of the hole can be appropriately designed, but is preferably 0.007 inches (in) to 0.011 inches (in).

[0081] In the present invention, the flow rate of the coolant injected from the coolant injector 130 is preferably 100 ml / min or more and 500 ml / min or less. If the flow rate is 500 ml / min or more, the formation of splats is suppressed due to excessive water supply, which makes it difficult to form a normal film.

[0082] The coolant flow path 132 may be connected to a coolant source (not shown). In the present invention, the coolant temperature may be appropriately set, for example, deionized water (DI water) at room temperature may be used.

[0083] Preferably, the coolant flow from the coolant injector 130 intersects the plasma flow. Figure 1 and Figure 2 An example in which the coolant flow is substantially orthogonal to the plasma flow is shown, however, the intersection angle of the coolant flow and the plasma flow can be set at various angles. For example, the intersection angle of the coolant flow axis and the plasma flow axis can be appropriately adjusted within the range of 45° to 135°.

[0084] In the present invention, the coolant flow has a much lower temperature than the plasma flow and / or the powder in the plasma flow, so the plasma flow and / or the powder in the flow can be cooled. As mentioned above, in the present invention, the term "coolant" is given because the temperature of the liquid ejected from the coolant injector 130 is relatively lower than the temperature of the plasma flow or the molten powder, and is not intended to define the YAG crystallization mechanism of the present invention. The high-crystallinity YAG thermal spray coating obtained by the apparatus and method of the present invention can be attributed to the cooling effect of the coolant, or to other different mechanisms. For example, in the present invention, the coolant can reduce the internal energy of the molten droplets in the plasma flow. This reduction in internal energy can alleviate the quenching effect that occurs after the molten droplets collide with the base material. Therefore, the crystallinity of the plasma thermal spray coating 14 containing YAG that collides with the base material can be increased.

[0085] The plasma thermal spray coating 14 containing YAG of the present invention exhibits high crystallinity. The thermal spray coating of the present invention has a fine structure in which a crystalline region and an amorphous region alternate on a two-dimensional cross section. In the present invention, the crystalline region exhibits a higher hardness than the amorphous region. Preferably, the Vickers hardness (Hv) of the crystalline region may be 1000 or more, 1050 or more, 1100 or more, or 1150 or more. Compared with the Vickers hardness (Hv) of 600 to 790 as the amorphous region in the thermal spray coating, this value is much higher. Exemplarily, in the present invention, the ratio of the Vickers hardness (B) of the crystalline region to the Vickers hardness (A) of the amorphous region may be 1.3 or more, 1.35 or more, 1.40 or more, 1.45 or more, 1.50 or more, 1.55 or more, 1.60 or more, 1.65 or more, 1.70 or more, 1.75 or more, 1.80 or more.

[0086] In addition, the plasma thermal spray coating of the present invention has high crystallinity. In the present invention, the crystallinity can be calculated based on the peak corresponding to the crystal plane of YAG (cubic) on the XRD spectrum and the background intensity. For example, the crystallinity can be calculated by using the plasma thermal spray coating of the present invention. ( The data were obtained using the HighScore Plus software of the EMPYREAN instrument of Panalytical BV (X-ray source: Cu Ka, voltage: 40 kW, current: 30 mA).

[0087] In the present invention, the calculated crystallinity may be 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, or 80% or more.

[0088] The cross section of the YAG thermal spray coating of the present invention can be divided into a bright area and a dark area in an electron microscope image. The bright area in the electron microscope image corresponds to the crystalline phase area. For example, the average area of ​​the crystalline phase area can be 100 μm 2 Above, 200μm 2 Above, 300μm 2 Above or 400μm 2 above.

[0089] In the present invention, the plasma thermal sprayed film preferably has high crystallinity and low porosity. In the present invention, the porosity of the film can be adjusted by the particle size of the raw material powder. Preferably, in the present invention, the plasma thermal sprayed film can be 5% or less, 4.5% or less, 4% or less, 3.5% or less, 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, 1.4% or less, 1.3% or less, or 1.2% or less.

[0090] Hereinafter, the present invention will be described in detail by illustrating embodiments of the present invention.

[0091] A. Raw powder for thermal spraying

[0092] YAG powder having a particle size of 1 μm or less was granulated to prepare a raw material powder for thermal spraying. The prepared granulated powder was prepared by changing D50 to 18 μm to 75 μm. Figure 3 This is a SEM photograph of the particle powder sample prepared in the present invention.

[0093] B. Preparation of thermal spray coating

[0094] Using the raw material powder of thermal spraying and Figure 1 The apparatus shown in the figure is used to prepare the thermal spray coating by atmospheric plasma spraying (APS). At this time, 6061 aluminum (50 mm*50 mm*5 mm (t)) is used as the base material substrate.

[0095] The plasma thermal spraying conditions for preparing the thermal sprayed coating are summarized and shown in Table 1 below.

[0096] Table 1

[0097]

[0098] Experiments were conducted by changing the particle size D50 of the raw material powder, the distance between the plasma torch nozzle and the base material, and the flow rate of the coolant injector. The experimental results showed that when using granular powder, it was necessary to adjust the coolant flow rate as the powder particle size increased. It was shown that as the particle size of the granular powder increased, reducing the coolant flow rate was conducive to forming a good film.

[0099] On the other hand, for comparison, Comparative Examples 3 to 7, Comparative Example 1, and Comparative Example 2 were prepared. Comparative Examples 3 to 7 are samples obtained by plasma thermal spraying of particulate raw material powder without using a coolant injector. Comparative Example 1 and Comparative Example 2 are samples prepared by plasma thermal spraying by supplying, as a suspension, raw material powder (D50 = 5.8 μm) that uses a coolant injector and is not granulated. In the case of non-granular fine powder smaller than 15 μm, such as in Comparative Example 1 and Comparative Example 2, dry supply is difficult, so it is supplied in the form of a suspension.

[0100] The experimental conditions of each example and comparative example are shown in Table 2. The porosity, hardness, and crystallinity of the prepared thermal spray coating were measured. The measurement methods for each physical property are as follows.

[0101] - Porosity: After installing the sample on which the coating to be measured has been formed, the cross-section was polished using sandpaper with 400 to 4000 mesh and a diamond (3 μm to 0.05 μm) suspension. After taking an image of the polished surface with an electron microscope, the ratio of the area of internal pores to the total coating area was calculated using the ImagePro program to calculate the porosity.

[0102] - Hardness: The fine structure of the coating cross-section was observed with an optical microscope, and the hardness of the amorphous part (A) and the hardness of the crystalline part (B) were measured. The hardness was measured using an HM-124 device from Mitutoyo Corporation of Japan in accordance with ASTM E384 standards.

[0103] - Crystallinity: X-ray diffraction analysis was performed on the coating surface, and the crystallinity was calculated from the peaks of the obtained XRD pattern. A baseline was created in the XRD chart, and the area of the peak part and the area of the amorphous part were calculated based on the baseline. The crystallinity was calculated using the following formula. At this time, an EMPYREAN device from Panalytical B.V. of the Netherlands ( (X-ray source: Cu Ka, voltage: 40 kW, current: 30 mA) was used to measure and calculate the X-ray diffraction analysis and crystallinity.

[0104] The measurement results are shown in Table 2 below.

[0105] Table 2

[0106]

[0107] Figure 4 Parts (a) to (f) are electron microscope photos taken after polishing the cross-sections of the samples of Examples 1 to 6, respectively.

[0108] Refer to Figure 4As can be seen from part (a), a dense thermal spray coating is formed on the surface of the base material. Figure 4 As shown in part (b), the pores increase slightly.

[0109] On the other hand, Figure 4 As shown in part (c) of FIG. 1 , it can be seen that when the particle size of the raw material powder is reduced, a denser film can be formed. On the contrary, Figure 4 As shown in parts (d) to (f) of the graphite sheet, it can be seen that when the particle size increases, the pores tend to increase.

[0110] In the present invention, the particle size D50 of the raw material powder is preferably 10 μm or more, 15 μm or more, or 18 μm or more. In addition, in the present invention, the particle size D50 of the particles is preferably 70 μm or less, 60 μm or less, 50 μm or less, or 45 μm or less.

[0111] On the other hand, Examples 4 to 6 show very high crystallization rates, which indicates that the particles are deposited in a state that has not reached a completely molten state during thermal spraying and exist in a powder state inside the coating layer. Comparative Examples 5 and 7 also obtain relatively high crystallization rates, which should be due to the same reason.

[0112] Figure 5 Parts (a) to (g) are electron microscope photographs taken after polishing the cross sections of the samples of Comparative Examples 1 to 7.

[0113] Figure 5 In the case of parts (a) and (b), it can be seen that a dense film can be obtained from the sample prepared using the fine raw material powder that has not been granulated as a suspension. However, for the small particle size sample prepared from the suspension, it can be seen that the crystallinity is very low.

[0114] On the other hand, in the case of the samples obtained by plasma thermal spraying the granular raw material powder without using a coolant injector, a dense film was obtained, but it was found that each showed a lower crystallinity than the samples of the corresponding examples.

[0115] Reference Figure 5 From parts (c) to (g), it can be seen that even when the coolant injector is not used, the density of the film shows a trend similar to that of the example according to the increase or decrease in the particle size of the raw material powder.

[0116] Figure 6 Parts (a) and (b) are optical microscope photographs of the cross section and the surface of the film of Example 1, respectively.

[0117] Reference Figure 6 As can be seen from part (a) of the photo, there are bright areas (see arrows) and dark areas, indicating that these areas are different phase areas. From the XRD spectrum described later, it can be seen that the former corresponds to the crystalline phase and the latter corresponds to the amorphous phase. Figure 6 A crystalline phase is also confirmed in part (b) (see arrow).

[0118] The hardness value of the crystalline phase proposed in the embodiment of the present invention is the hardness value measured in the arrow area, and the hardness value of the amorphous phase is the hardness value measured in the dark area.

[0119] Figure 7 Parts (a) and (b) are optical microscope photographs of the cross section and the surface of the film of Comparative Example 3, respectively.

[0120] Reference Figure 7 In the case of Comparative Example 3, a bright portion (see arrow) is also observed, but it is known that its area is significantly smaller than that of Example 1. As described above, the area of ​​the crystalline phase is much smaller than the size of the hardness tester indenter used to measure the Vickers hardness, and therefore, the Vickers hardness measured for the crystalline phase is substantially the same as the value measured in the amorphous phase region, and therefore, is not separately shown in Table 2.

[0121] Figure 8 Parts (a) and (b) are optical microscope photographs of the film surfaces of Comparative Examples 1 and 2. As in Comparative Example 3, the area of ​​the crystalline phase is much smaller than the size of the hardness tester indenter used to measure the Vickers hardness, so the Vickers hardness measured for the crystalline phase is substantially the same as the value measured in the amorphous phase region, and therefore, is not separately shown in Table 2.

[0122] Fig. 9 Parts (a) to (d) are photographs showing the XRD analysis results of the plasma thermal sprayed films formed in Comparative Example 1, Comparative Example 2, Example 1, and Example 2, respectively.

[0123] like Fig. 9 As shown in parts (a) and (b) of FIG. 1 , it can be seen that a very high background intensity appears at a low angle near 2θ=30°, and a high background intensity appears until near 2θ=60°.

[0124] On the other hand, Fig. 9 As shown in parts (c) and (d) of FIG. 1 , it can be seen that when coolant spraying is used in the plasma thermal spray coating process, the background intensity at low angles is significantly reduced.

[0125] Fig.10 It shows that Fig. 9 A graph showing the results of XRD peak indexing for a portion of the spectrum.

[0126] As shown in the figure, in the case of a highly crystallized film as in Example 1, high diffraction intensity is shown in the order of peaks corresponding to crystal planes 420, 211, 640, and 400, thereby confirming that a YAG coating film has been formed. In this embodiment, the four crystal planes correspond to 2θ=18.09°, 2θ=29.75°, 2θ=33.35°, and 2θ=55.13° (2θ error range: ±1°). The crystallinity was calculated based on the XRD analysis results, and the results are shown in Table 2.

[0127] The present invention is described above by means of exemplary embodiments and drawings, however, this is only to help fully understand the present invention, the present invention is not limited to the embodiments, and a person skilled in the art of the present invention can make various modifications and variations within the scope of the essential characteristics of the present invention. Therefore, the spirit of the present invention should not be limited to the embodiments described and determined, not only the claims, but all technical ideas that are equivalent to or equivalently modified to the claims should be interpreted as included within the scope of the present invention.

Claims

1. A method for preparing a plasma thermal spray coating, wherein the thermal spray coating contains yttrium aluminum garnet (YAG), characterized in that: The following steps are involved: Providing a granular powder containing yttrium aluminum garnet (YAG) crystals; forming a plasma stream from a plasma torch toward a base material; supplying the particle powder to the plasma stream to form molten droplets of the particle powder; providing a coolant flow in a direction intersecting the plasma flow containing the molten droplets; as well as A plasma flow passing through the coolant flow is provided to the thermal spraying base material to form the plasma thermal spraying film including a crystalline phase and an amorphous phase.

2. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: The step of forming molten droplets of the granular powder is to partially melt the granular powder in a state where yttrium aluminum garnet (YAG) crystals are contained in the molten droplets.

3. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: The particle powder has a D50 of 15 μm to 75 μm.

4. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: The particle powder has a D50 of 15 μm to 45 μm.

5. The method for preparing a plasma thermal spray coating according to claim 3 or 4, characterized in that: The plasma thermal sprayed film has a crystallinity of 45% or more.

6. The method for preparing a plasma thermal spray coating according to claim 3 or 4, characterized in that: The porosity of the plasma thermal sprayed film is 1% to 3.1%.

7. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: The coolant stream comprises water.

8. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: The plasma torch is spaced from the base material by a distance of 80 mm to 160 mm.

9. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: comprising a coolant injector for supplying said coolant flow, The coolant injector is annular in shape surrounding the plasma stream.

10. The method for preparing a plasma thermal spray coating according to claim 9, characterized in that: The coolant injector is provided with a plurality of injection holes on its inner surface facing the plasma flow.

11. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: The flow rate of the coolant stream is 100 ml / min to 500 ml / min.

12. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: The amorphous phase has a Vickers hardness of 700 to 800.

13. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: The Vickers hardness of the crystalline phase is 1000 to 1110.

14. The method for preparing a plasma thermal spray coating according to claim 1, characterized in that: The Vickers hardness of the crystalline phase relative to the Vickers hardness of the amorphous phase is 1.3 to 1.

6.

15. A plasma thermal sprayed coating, comprising Y-Al-O, characterized in that: The Y-Al-O in the plasma thermal spraying film includes a crystalline phase and an amorphous phase. The crystal phase comprises yttrium aluminum garnet YAG, The Vickers hardness Hv of the crystal phase is 1000 or more.

16. The plasma thermal spraying film according to claim 15, characterized in that: A ratio of the Vickers hardness of the crystalline phase to the Vickers hardness of the amorphous phase is 1.3 or more.

17. The plasma thermal spraying film according to claim 15, characterized in that: The crystallinity of the yttrium aluminum garnet YAG calculated from the X-ray diffraction pattern of the yttrium aluminum garnet YAG is 45% or more.

18. The plasma thermal spraying film according to claim 15, characterized in that: The cross section of the plasma thermal sprayed film includes a bright region representing the crystal phase in an optical microscope image, The average area of ​​the bright area is 100 μm 2 above.

19. A plasma-resistant component, characterized in that: include: parent material, and The plasma thermal sprayed coating according to any one of claims 15 to 18 formed on the base material.

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