Thermal spray material and method for forming thermal spray coating using the same

Abstract

To provide a thermal spray material with which a thermal spray coating presenting a performance equal to that of a conventional one can be achieved more easily than the conventional one, and a method of forming a thermal spray coating with the thermal spray material.SOLUTION: A thermal spray material for forming a thermal spray coating including a rare earth oxyhalide, includes rare earth halide powder and rare earth oxide powder. Thermally spraying the thermal spray material on a substrate forms, on the substrate, a thermal spray coating B2 including the rare earth oxyhalide.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a thermal spray material for forming a thermal spray coating containing a rare earth oxyhalide, and a method for forming a thermal spray coating using the same. [Background technology]

[0002] Thermal spray coatings formed by thermally spraying a thermal spray material onto a substrate are used for various purposes depending on the material properties of the thermal spray material. For example, thermal spray coatings using rare earth oxyhalides such as yttrium fluoride oxide as the thermal spray material exhibit high plasma erosion resistance (etching resistance, corrosion resistance, etc.) when exposed to plasma, and are therefore used as protective coatings for components in semiconductor device manufacturing equipment that processes using plasma.

[0003] Conventionally, when forming such a thermal spray coating of a rare earth oxyhalide, a thermal spray material of the rare earth oxyhalide is manufactured, and the thermal spray material is sprayed to form a thermal spray coating of the rare earth oxyhalide. That is, for example, the raw materials of rare earth oxide and rare earth halide are mixed, granulated, degreased, heat-treated, fired, crushed, and classified to manufacture a powdered thermal spray material of the rare earth oxyhalide, or the powdered rare earth oxyhalide is further crushed and dispersed in a dispersion medium to manufacture a slurry-like thermal spray material (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-061738 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional thermal spray materials as described above are produced in a very time-consuming manner, since the raw materials are mixed and granulated, heated and sintered, and then crushed and classified to produce a powder, or further pulverized and dispersed in a dispersion medium to produce a slurry.

[0006] In view of the above, an object of the present invention is to provide a thermal spray material that can easily produce a thermal spray coating containing a rare earth oxyhalide, and a method for forming a thermal spray coating using the same. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the thermal spray material according to the present invention is a thermal spray material for forming a thermal spray coating containing a rare earth oxyhalide, which contains a rare earth halide powder and a rare earth oxide powder (excluding Gd2O3 powder), and the average particle diameter (D 50 )but 1 The average particle diameter (D 50 )but 0.5 It is characterized in that the thickness is between 1 μm and 3 μm.

[0008] In addition, in order to solve the above-mentioned problems, the method of forming a thermal spray coating according to the present invention is characterized in that the thermal spray coating containing the rare earth oxyhalide is formed on a substrate by thermally spraying the above-mentioned thermal spray material onto the substrate. Effect of the Invention

[0009] According to the thermal spray material and the method for forming a thermal spray coating using the same according to the present invention, a thermal spray coating containing a rare earth oxyhalide can be easily obtained. [Brief description of the drawings]

[0010] [Figure 1] 1 is a scanning electron microscope photograph of a thermal spray coating B1 of an example. [Diagram 2] 1 is a scanning electron microscope photograph of a thermal spray coating B2 of an example. [Diagram 3] 1 is a scanning electron microscope photograph of the thermal spray coating B3 of the example. [Figure 4] 1 is a scanning electron microscope photograph of the thermal spray coating B4 of the example. [Diagram 5] 1 is a scanning electron microscope photograph of the thermal spray coating B5 of the example. [Figure 6] 1 is a scanning electron microscope photograph of a thermal spray coating B6a of an example. [Figure 7] 1 is a scanning electron microscope photograph of a thermal spray coating B6b of an example. [Figure 8] 1 is a scanning electron microscope photograph of a thermal spray coating B6c of an example. [Figure 9] 1 is a scanning electron microscope photograph of the thermal spray coating B7 of the example. [Figure 10] 1 is a scanning electron microscope photograph of the thermal spray coating B8 of the example. [Figure 11] 1 is a scanning electron microscope photograph of the thermal spray coating B9 of the example. [Figure 12] 1 is a graph showing the results of X-ray diffraction analysis of a thermal spray coating B1 of an example. [Figure 13] 1 is a graph showing the results of X-ray diffraction analysis of the thermal spray coating B2 of the example. [Figure 14] 1 is a graph showing the results of X-ray diffraction analysis of the thermal spray coating B3 of the example. [Figure 15] 1 is a graph showing the results of X-ray diffraction analysis of the thermal spray coating B4 of the example. [Figure 16] 1 is a graph showing the results of X-ray diffraction analysis of the thermal spray coating B5 of the example. [Figure 17] 1 is a graph showing the results of X-ray diffraction analysis of a thermal spray coating B6a of an example. [Figure 18] 1 is a graph showing the results of X-ray diffraction analysis of the thermal spray coating B6b of the example. [Figure 19] 1 is a graph showing the results of X-ray diffraction analysis of the thermal spray coating B6c of the example. [Figure 20] 1 is a graph showing the results of X-ray diffraction analysis of the thermal spray coating B7 of the example. [Figure 21]1 is a graph showing the results of X-ray diffraction analysis of the thermal spray coating B8 of the example. [Figure 22] 1 is a graph showing the results of X-ray diffraction analysis of the thermal spray coating B9 of the example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of the thermal spray material and the method of forming a thermal spray coating using the same according to the present invention will be described below, but the present invention is not limited to the embodiment described below.

[0012] [Main embodiment] Main embodiments of the thermal spray material and the method for forming a thermal spray coating using the same according to the present invention will be described below.

[0013] The thermal spray material according to this embodiment is a thermal spray material for forming a thermal spray coating containing a rare earth oxyhalide, and contains a rare earth halide powder and a rare earth oxide powder.

[0014] The rare earth halide powder may be yttrium fluoride (YF3) or yttrium chloride (YCl3), and is preferably yttrium fluoride (YF3). The rare earth halide powder has an average particle diameter (D 50 ) is preferably 0.3 μm or more and 3 μm or less. If it is less than 0.3 μm, it becomes difficult to form a slurry, which is not preferable, and if it exceeds 3 μm, the composition of the coating formed when thermally sprayed tends to be non-uniform, which is also not preferable.

[0015] The rare earth oxide powder may be yttrium oxide (Y2O3) or the like. The rare earth oxide powder has an average particle diameter (D 50 ) is preferably 0.05 μm or more and 3 μm or less. This is because if it is less than 0.05 μm, the aggregated powder becomes difficult to break down, which is undesirable, and if it exceeds 3 μm, the yttrium oxide (Y2O3) phase tends to be present locally in the thermal spray coating, which tends to reduce the plasma resistance of the thermal spray coating, which is undesirable.

[0016] The average particle diameter of the rare earth oxide powder (D 50 ) is the average particle diameter of the rare earth halide powder (D 50 ) or less, the rare earth oxide powder and the rare earth halide powder are more likely to react with each other and form rare earth oxyhalide, which is preferable.

[0017] In addition, the above "average particle size (D 50 ) refers to the particle size at the cumulative 50% particle size (cumulative 50% particle size) in the volume-based particle size distribution measured using a particle size distribution measuring device based on the laser diffraction / scattering method (for example, the Mastersizer 3000 (product name) manufactured by Malvern Instruments, UK).

[0018] In addition, in the thermal spray material according to the present embodiment, the ratio of the content (mass) of the rare earth oxide powder to the content (mass) of the rare earth halide powder is preferably 0.1 or more and 0.5 or less. This is because if the ratio is less than 0.1, the amount of yttrium fluoride oxide (YOF) phase formed in the thermal spray coating becomes too small, which is undesirable as it becomes difficult to sufficiently improve the plasma resistance of the thermal spray coating, and if the ratio exceeds 0.5, the yttrium oxide (Y2O3) phase tends to be locally present in the thermal spray coating, which is undesirable as it tends to reduce the plasma resistance of the thermal spray coating.

[0019] In particular, when yttrium fluoride (YF3) and yttrium oxide (Y2O3) are used as raw materials, mixing yttrium fluoride (YF3) and yttrium oxide (Y2O3) so that the ratio of yttrium element, oxygen element, and fluorine element (Y:O:F) is 1:1:1 in molar ratio makes it easier for the thermal spray coating to form a single phase of YOF, which is highly preferable.

[0020] Furthermore, it is highly preferable that the thermal spray material according to the present embodiment is a slurry in which a rare earth halide powder and a rare earth oxide powder are mixed and dispersed in a dispersion medium. The dispersion medium is not particularly limited as long as it can disperse the powder, but examples of the dispersion medium include ion-exchanged water, alcohol liquid, and a mixture of ion-exchanged water and alcohol liquid.

[0021] The slurry is preferably a mixture in which the mass ratio of the dispersion medium to the total of the rare earth halide powder and the rare earth oxide powder is 9:1 to 5:5 (9:1 to 7:3 is particularly preferable).This is because if the mass ratio of the dispersion medium is smaller than the above range, the rare earth halide in the composition of the coating formed by thermal spraying tends to be excessive, which is undesirable, and if the mass ratio of the dispersion medium is larger than the above range, the rare earth oxide in the coating formed by thermal spraying tends to remain as a single phase, which is undesirable.

[0022] The slurry can contain various additives in addition to the powder in the dispersion medium, and for example, it is preferable to mix a dispersant (anionic, cationic, nonionic, etc.) therein.

[0023] By spraying such a thermal spray material according to this embodiment onto a substrate, a thermal spray coating containing a rare earth oxyhalide can be formed on the substrate, thereby imparting environmental barrier properties (typically, plasma erosion resistance) to the substrate.

[0024] In this embodiment, yttrium fluoride is used as the rare earth halide powder and yttrium oxide is used as the rare earth oxide powder, thereby forming a thermal spray coating of yttrium fluoride oxide (YOF), which is a rare earth oxyhalide.

[0025] The thermal spray material according to the present embodiment may further contain powders of other compounds other than the above-mentioned powders. However, since the thermal spray coating mainly composed of yttrium fluoride oxide has excellent plasma erosion resistance, particularly erosion resistance against halogen plasma, a thermal spray material capable of forming a larger amount of yttrium fluoride oxide is preferable because it can form a thermal spray coating with extremely excellent plasma erosion resistance.

[0026] The substrate is not particularly limited as long as it has a material and shape that can withstand the spraying of the spray material, and examples thereof include various metals and alloys, etc. Specific examples thereof include aluminum, aluminum alloys, iron, steel, copper, copper alloys, nickel, nickel alloys, gold, silver, bismuth, manganese, zinc, zinc alloys, etc.

[0027] Among these, among commonly used metal materials, particularly preferred are steels having a relatively large thermal expansion coefficient, such as various SUS materials (so-called stainless steels), heat-resistant alloys such as Inconel, low-expansion alloys such as Invar and Kovar, corrosion-resistant alloys such as Hastelloy, and aluminum alloys such as 1000-7000 series aluminum alloys useful as lightweight structural materials, etc. Examples of substrates made of such materials include members constituting semiconductor device manufacturing equipment and used in environments exposed to highly reactive oxygen gas plasma, halogen-based plasma, etc.

[0028] The halogen-based plasma is typically a plasma generated by using a plasma generating gas containing a halogen-based gas (halogen compound gas). Specifically, typical examples include plasma generated by using a single type of halogen-based gas, such as fluorine-based gases such as SF6, CF4, CHF3, ClF3, HF, etc., used in dry etching processes in the manufacture of semiconductor substrates, chlorine-based gases such as Cl2, BCl3, HCl, and bromine-based gases such as HBr, or a mixture of two or more types. These gases can also be mixed with an inert gas such as argon (Ar).

[0029] As a method for spraying the thermal spray material according to the present embodiment, various known thermal spray methods such as plasma thermal spraying, high velocity flame thermal spraying, flame thermal spraying, detonation thermal spraying, aerosol deposition method, etc. can be applied, but the plasma thermal spraying is particularly suitable. The plasma thermal spraying is a method that uses a plasma flame as a heat source for softening or melting the thermal spray material.

[0030] That is, it is a coating method in which an arc is generated between electrodes, a working gas is turned into plasma by this arc and ejected from a nozzle as a high-temperature and high-speed plasma jet, and a thermal spray material is supplied to this plasma jet, heated and accelerated, and the thermal spray material is deposited on a substrate to form a thermal spray coating. Specifically, for example, the thermal spray material is melted and accelerated by a plasma jet at a temperature of about 5000 to 10000°C and a speed of about 300 to 600 m / s, and is made to collide with the substrate.

[0031] Such plasma spraying methods include atmospheric plasma spraying (APS), in which spraying is performed in the atmosphere, low pressure plasma spraying (LPS), in which spraying is performed under reduced pressure lower than atmospheric pressure, and high pressure plasma spraying (HPS), in which spraying is performed under pressure higher than atmospheric pressure, and all of these can be applied.

[0032] The thermal spray coating according to this embodiment formed on the substrate in this manner can exhibit performance equivalent to that of conventional thermal spray coatings using a powdered rare earth oxyhalide thermal spray material obtained by mixing and granulating the raw materials of rare earth oxide powder and rare earth halide powder, heating and sintering the mixture, and then crushing and classifying the mixture, or a slurry-like thermal spray material obtained by further crushing the mixture and dispersing it in a dispersion medium.

[0033] In other words, in the past, the raw materials of rare earth oxide powder and rare earth halide powder were mixed and fired prior to thermal spraying to obtain a rare earth oxyhalide thermal spray material, and this thermal spray material was then sprayed to form a thermal spray coating of rare earth oxyhalide on a substrate. However, in this embodiment, a thermal spray material that is a mixture of rare earth oxide powder and rare earth halide powder is sprayed, and a thermal spray coating of rare earth oxyhalide is formed on a substrate while rare earth oxyhalide is generated by the heat during spraying.

[0034] Therefore, the thermal spray material according to this embodiment can be manufactured with less effort than conventional thermal spray materials.

[0035] Therefore, according to this embodiment, a thermal spray coating of a rare earth oxyhalide can be obtained more easily than in the past. EXAMPLES

[0036] Examples of the thermal spray material and the method of forming a thermal spray coating using the same according to the present invention will be described below, but the present invention is not limited to the specific examples described below.

[0037] [Preparation of thermal spray material] <Thermal spray material A1> Average particle diameter (D 50 ) 3μm yttrium fluoride (YF3) powder and average particle size (D 50)3μm yttrium oxide (Y2O3) powder was added to the ion-exchanged water as a dispersion medium so that the ratio of the mass of yttrium oxide (Y2O3) to the mass of yttrium fluoride (YF3) was 0.429 (YF3:Y2O3=7:3), and an anionic dispersant was added as an additive to the ion-exchanged water so that the ratio to the total mass of the yttrium fluoride (YF3) powder and the yttrium oxide (Y2O3) powder was 0.05 mass%, and the mixture was stirred and mixed to produce a slurry-like thermal spray material A1. The mixing ratio of the dispersion medium (ion-exchanged water) to the yttrium fluoride (YF3) powder and the yttrium oxide (Y2O3) powder was 7:3 by mass.

[0038] <Thermal spray material A2> A slurry-like thermal spray material A2 was produced under the same conditions as thermal spray material A1, except that yttrium fluoride (YF3) powder and yttrium oxide (Y2O3) powder were added to ion-exchanged water so that the ratio of the mass of yttrium fluoride (YF3) to the mass of yttrium oxide (Y2O3) was 0.250 (YF3:Y2O3 = 8:2).

[0039] <Thermal spray material A3> A slurry-like thermal spray material A3 was produced under the same conditions as thermal spray material A1, except that yttrium fluoride (YF3) powder and yttrium oxide (Y2O3) powder were added to ion-exchanged water so that the ratio of the mass of yttrium fluoride (YF3) to the mass of yttrium oxide (Y2O3) was 0.111 (YF3:Y2O3 = 9:1).

[0040] <Thermal spray material A4> Average particle diameter (D 50 A slurry-like thermal spray material A4 was produced under the same conditions as the thermal spray material A1, except that 1 μm yttrium oxide (Y2O3) powder was used.

[0041] <Thermal spray material A5> Average particle diameter (D 50A slurry-like thermal spray material A5 was produced under the same conditions as the thermal spray material A1, except that 0.5 μm yttrium oxide (Y2O3) powder was used.

[0042] <Thermal spray material A6> Average particle diameter (D 50 ) 1 μm yttrium fluoride (YF3) powder and the average particle diameter (D 50 A slurry-like thermal spray material A6 was produced under the same conditions as thermal spray material A1, except that a 0.5 μm yttrium oxide (Y2O3) powder was used and an anionic dispersant was added to the ion-exchanged water so that the proportion of the anionic dispersant to the total mass of the yttrium fluoride (YF3) powder and the yttrium oxide (Y2O3) powder was 0.3 mass%.

[0043] <Thermal spray material A7> A slurry-like thermal spray material A7 was produced under the same conditions as thermal spray material A6, except that an alcohol liquid was used as the dispersion medium and a nonionic dispersant was added to the alcohol liquid as an additive at a ratio of 1.0 mass% relative to the total mass of the yttrium fluoride (YF3) powder and yttrium oxide (Y2O3) powder.

[0044] <Thermal spray material A8> A slurry-like thermal spray material A8 was produced under the same conditions as thermal spray material A7, except that a mixture of alcohol and ion-exchanged water (alcohol containing 20% ​​by volume of ion-exchanged water) was used as the dispersion medium so that the volume ratio of the alcohol and ion-exchanged water was 8:2, and an anionic dispersant was further added as an additive so that the ratio relative to the total mass of the yttrium fluoride (YF3) powder and yttrium oxide (Y2O3) powder was 0.6 mass%.

[0045] <Thermal spray material A9> A slurry-like thermal spray material A9 was produced under the same conditions as thermal spray material A7, except that a mixture of alcohol liquid and ion-exchanged water (ion-exchanged water containing 20% ​​by volume of alcohol liquid) was used as the dispersion medium so that the volume ratio of the alcohol liquid to the ion-exchanged water was 2:8, and an anionic dispersant was further added as an additive so that the ratio relative to the total mass of the yttrium fluoride (YF3) powder and yttrium oxide (Y2O3) powder was 0.3 mass%.

[0046] [Table 1]

[0047] [Formation of thermal spray coating] The above spray materials A1 to A9 were used to plasma spray a substrate (material: Al alloy, size: 50 mm x 70 mm x 5 mm) using a plasma spraying device (Progressive Corp., USA, "100HE (model number)") under the conditions shown in Table 2 below, to form sprayed coatings B1 to B5, B6a to B6c, and B7 to B9 with a thickness of approximately 100 μm.

[0048] [Table 2]

[0049] [Evaluation method] Scanning Electron Microscope (SEM) The sprayed coatings B1 to B5, B6a to B6c, and B7 to B9 were cut out using a cutting machine, and then cross-sections were prepared using a "Cross Section Polisher (registered trademark)" manufactured by JEOL Ltd. to prepare samples for observation. Then, a backscattered electron image of the cross section was photographed (accelerating voltage: 10 kV) using an SEM ("Phenom Pro X (product name)" manufactured by Phenom World, Netherlands). The results are shown in Figures 1 to 11.

[0050] X-ray diffraction (XRD) analysis The thermal sprayed coatings B1 to B5, B6a to B6c, and B7 to B9 were subjected to XRD analysis (start angle: 20°, end angle: 35°) using an XRD analyzer (product name: Ultima IV, manufactured by Rigaku Corporation) in the as-sprayed state without polishing, etc. The results are shown in Figures 12 to 22 and Table 3.

[0051] [Evaluation Results] The evaluations of the thermal spray coatings B1 to B5, B6a to B6c, and B7 to B9 based on the results of SEM and X-ray diffraction analysis are shown in the following Table 3. In Table 3, "◎" indicates excellent, "◯" indicates good, "△" indicates applicable, and "×" indicates not applicable.

[0052] [Table 3]

[0053] As can be seen from FIGS. 1 to 11, the thermal spray coatings B1 to B5, B6a to B6c, and B7 to B9 all became dense coatings, and as shown in Table 3, none of them were rated as "x" (not applicable).

[0054] As can be seen from Table 3, in the thermal spray coatings B1 and B4, in which the average particle size of YF3 is relatively large (3 μm) and the amount of Y2O3 is relatively large (Y2O3 / YF3=0.492), the strength ratio of YF / Y2O3 according to the XRD analysis was relatively low, and therefore the evaluation was “△” (applicable).

[0055] In addition, in the thermal spray coatings B2 and B3, in which the average particle size of YF3 is relatively large (3 μm) but the amount of Y2O3 is relatively small (Y2O3 / YF3 = 0.111 to 0.250), the strength ratio of YF / Y2O3 according to the XRD analysis was moderate, and therefore the evaluation was "good."

[0056] In addition, in the thermal spray coatings B5, B6a to B6c, and B7 to B9, in which the average particle size of Y2O3 is relatively small (0.5 μm) and the amount of Y2O3 is relatively large (Y2O3 / YF3 = 0.492), the strength ratio of YF / Y2O3 was the highest according to the XRD analysis, and therefore the evaluation was "◎" (excellent).

[0057] From the above, it has been confirmed that according to the present invention, it is possible to obtain a thermal spray coating that can exhibit effects equal to or greater than those of the conventional method more easily than before. [Industrial Applicability]

[0058] The thermal spray material and the method for forming a thermal spray coating using the same according to the present invention can easily obtain a thermal spray coating of a rare earth oxyhalide, and therefore can be used industrially with great advantage.

Claims

1. A thermal spray material for forming a thermal spray coating containing a rare earth oxyhalide, Rare earth halide powder and rare earth oxide powder (Gd ２ O ３ Powders excluded) The average particle diameter (D ５０ ) is 1 μm or more and 3 μm or less, The average particle diameter (D ５０ ) is 0.5 μm or more and 3 μm or less A thermal spray material characterized by:

2. The average particle diameter (D ５０ ) is the average particle diameter (D ５０ ) or smaller The thermal spray material according to claim 1 .

3. The ratio of the content (mass) of the rare earth oxide powder to the content (mass) of the rare earth halide powder is 0.1 or more and 0.5 or less.

3. The thermal spray material according to claim 1 or 2.

4. Further comprising a dispersion medium, The dispersion medium is mixed with the rare earth halide powder and the rare earth oxide powder in a mass ratio of 9:1 to 5:

5. The thermal spray material according to any one of claims 1 to 3.

5. the rare earth halide powder is yttrium fluoride powder, The rare earth oxide powder is yttrium oxide powder. The thermal spray material according to any one of claims 1 to 4.

6. The rare earth halide powder and the rare earth oxide powder are mixed and dispersed in a dispersion medium to form a slurry. The thermal spray material according to any one of claims 1 to 5.

7. The dispersion medium is any one of ion-exchanged water, an alcohol liquid, and a mixture of ion-exchanged water and an alcohol liquid. The thermal spray material according to claim 6.

8. A method for forming the thermal spray coating containing the rare earth oxyhalide on a substrate by thermally spraying the thermal spray material according to any one of claims 1 to 7 onto the substrate.

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