Surface-treated aluminum material and member for plasma treatment device

Abstract

A surface-treated aluminum material (1) comprises a base material (2) that is made of aluminum or an aluminum alloy and a protective film (3) that is formed on the base material (2). The protective film (3) has: a first layer (31) that comprises an oxide of aluminum and covers the base material (2); and a second layer (32) that contains a hydrated oxide of aluminum and covers the first layer (31). When a high-temperature cycle test of the aluminum material (1) is performed under specific conditions, the number AHC of cracks per unit area formed in the protective film (3) falls within a specific range.

Description

Surface-treated aluminum materials and components for plasma processing equipment

[0001] The present invention relates to surface-treated aluminum materials and components for plasma processing equipment.

[0002] Aluminum materials, consisting of aluminum or aluminum alloys, are used in a wide variety of applications. These aluminum materials may have an anodic oxide coating applied to their surface to achieve various objectives, such as improved corrosion resistance, scratch resistance, and aesthetic appeal. Because the functions that can be imparted to aluminum materials by the anodic oxide coating are diverse, the application fields of aluminum materials with anodic oxide coatings are expanding rapidly.

[0003] For example, Patent Document 1 describes a component for a substrate processing apparatus that performs plasma processing on a substrate, wherein the component is connected to the anode of a DC power supply and a coating is formed on the surface of the component by an anodic oxidation treatment in which the component is immersed in a solution mainly composed of an organic acid, and the coating is subjected to a semi-sealing treatment using boiling water.

[0004] Japanese Patent Publication No. 2008-81815

[0005] However, the component described in Patent Document 1 has a problem in that its durability against corrosive gases and plasma is low because the pores of the anodic oxide film are not completely sealed.

[0006] On the other hand, in the component described in Patent Document 1, a method of completely sealing the pores of the anodic oxide film can be considered to improve durability against corrosive gases and plasma. However, in this case, cracks are more likely to occur in the anodic oxide film when the temperature rises, and there is a risk of foreign matter consisting of small fragments of the anodic oxide film being generated. In order to suppress the generation of such foreign matter, it is desirable to further improve the heat resistance of aluminum material having an anodic oxide film on its surface.

[0007] This invention has been made in view of the above background, and aims to provide a surface-treated aluminum material, a method for manufacturing the same, and a component for a plasma processing apparatus that has excellent corrosion resistance to corrosive gases and plasma, and can suppress the occurrence of cracks even when the temperature rises.

[0008] One aspect of the present invention is a surface-treated aluminum material having a base material made of aluminum or an aluminum alloy and a protective film formed on the base material, wherein the protective film is composed of an aluminum oxide and has a first layer covering the base material and a second layer containing hydrated aluminum oxide and covering the first layer. When a high-temperature cycle test is performed in which the surface-treated aluminum material is left standing in an atmosphere of 25°C for 30 minutes, then the temperature of the atmosphere is raised to 200°C over 60 minutes, left standing in an atmosphere of 200°C for 30 minutes, and then the temperature of the atmosphere is lowered to 25°C over 60 minutes, and this cycle is repeated 100 times, the number A per unit area of cracks formed in the protective film, represented by the following formula (1) HC is 10 / mm 2 or less, in the surface-treated aluminum material. A HC = (nx HC + ny HC ) / S HC ... (1)

[0009] In the formula (1), S HC is the visual field area (unit: mm 2 ) of a magnified photograph obtained by magnifying the surface of the protective film after the high-temperature cycle test 500 times, nx HC is the number of intersections of cracks appearing in the magnified photograph and a first straight line passing through the center of the magnified photograph and parallel to the horizontal direction of the magnified photograph, and ny HC is the number of intersections of cracks appearing in the magnified photograph and a second straight line passing through the center of the magnified photograph and parallel to the vertical direction of the magnified photograph.

[0010] Another aspect of the present invention is a member for a plasma processing apparatus made of the surface-treated aluminum material of the above aspect.

[0011] The surface-treated aluminum material (hereinafter referred to as "aluminum material") comprises a first layer made of aluminum oxide and a second layer containing hydrated aluminum oxide that covers the first layer, and has a protective film formed on the base material. Furthermore, the number of cracks per unit area formed in the protective film after the surface-treated aluminum material is subjected to a high-temperature cycle test under the specific conditions is 10 / mm². 2 The following is true: Aluminum materials possessing these properties exhibit excellent corrosion resistance to corrosive gases and plasma, as well as superior heat resistance, and can suppress crack formation even when the temperature rises.

[0012] Since the plasma processing apparatus component is made of the aforementioned aluminum material, it has excellent corrosion resistance to corrosive gases and plasma, as well as excellent heat resistance, and can suppress the occurrence of cracks even when the temperature rises.

[0013] As described above, according to the above embodiment, it is possible to provide a surface-treated aluminum material, a method for manufacturing the same, and a component for a plasma processing apparatus that have excellent corrosion resistance to corrosive gases and plasma, and can suppress the occurrence of cracks even when the temperature rises.

[0014] Figure 1 is a cross-sectional view of the surface-treated aluminum material in the example. Figure 2 is a cross-sectional view of the base material on which the first layer was formed during the manufacturing process of the surface-treated aluminum material in the example. Figure 3 is a schematic diagram of an enlarged photograph of the protective film after a high-temperature cycle test in the example.

[0015] (Surface-treated aluminum material) The base material of the aluminum material is made of aluminum or an aluminum alloy. The shape of the base material is not particularly limited and can take various shapes depending on the application of the aluminum material. For example, the base material may be a wrought material such as a rolled plate or an extruded material, or it may be a cast material or a forged material. The base material may also be machined to form a desired shape. When the shape of the base material is a plate, the thickness of the base material is not particularly limited. More specifically, the base material may be a cold-rolled plate with a thickness of about 1 mm, or a hot-rolled plate with a thickness of about 50 mm.

[0016] Furthermore, the material of the base material can be appropriately selected from the group consisting of aluminum and aluminum alloys, depending on the application of the aluminum material. More specifically, for example, 1000 series aluminum can be used as the aluminum constituting the base material. For example, 2000 series aluminum alloy, 3000 series aluminum alloy, 4000 series aluminum alloy, 5000 series aluminum alloy, 6000 series aluminum alloy, 7000 series aluminum alloy, and 8000 series aluminum alloy can be used as the aluminum alloy constituting the base material. In addition, the base material may be a clad material in which two or more layers having different chemical compositions are laminated together.

[0017] A protective film is provided on the base material, comprising a first layer laminated on the base material and a second layer laminated on the first layer. The thickness of the protective film is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and particularly preferably 20 μm or more. In this case, the corrosion resistance of the aluminum material can be more reliably improved. From the viewpoint of improving corrosion resistance, there is no particular upper limit to the thickness of the protective film, but the manufacturing upper limit for the thickness of the protective film is, for example, 200 μm. From the viewpoint of further increasing the productivity of the aluminum material, the thickness of the protective film is preferably 150 μm or less, more preferably 100 μm or less, and even more preferably 60 μm or less.

[0018] In determining the preferred range of thickness for the protective film, the upper and lower limits of the protective film described above can be arbitrarily combined. The preferred range of thickness for the protective film may be, for example, 5 μm to 200 μm, 5 μm to 150 μm, 5 μm to 100 μm, 5 μm to 60 μm, 10 μm to 60 μm, 15 μm to 60 μm, or 20 μm to 60 μm.

[0019] The first layer is composed of aluminum oxide. The first layer may have pores. That is, the first layer may be a porous type anodic oxide film. Alternatively, the first layer may be a barrier type anodic oxide film that does not have pores. From the viewpoint of making it easier to increase the thickness of the anodic oxide film, it is preferable that the first layer has pores.

[0020] The second layer contains hydrated aluminum oxide. Because hydrated aluminum oxide has high chemical stability, it is less likely to deteriorate during use of the aluminum material. In addition, hydrated aluminum oxide also has excellent corrosion resistance.

[0021] Furthermore, the second layer is formed, for example, by hydrating the aluminum oxide contained in the first layer after the first layer has been formed by anodizing the base material. When aluminum oxide is hydrated, the hydrated oxide grows from the surface of the aluminum oxide, making it difficult for defects to form between the aluminum oxide and the hydrated oxide. Therefore, by forming a second layer containing aluminum hydrate on the first layer, the formation of defects at the interface between the first and second layers can be suppressed. As a result, by providing a second layer containing aluminum hydrate on the first layer, high corrosion resistance can be maintained over a long period of time.

[0022] More specifically, the second layer may be composed of a hydrated aluminum oxide. Alternatively, the second layer may be composed of a hydrated aluminum oxide and oxides and / or hydroxides of metal elements other than aluminum. Examples of metal elements included in the second layer include Ni (nickel), Cr (chromium), Zr (zirconium), Si (silicon), Ti (titanium), Au (gold), Ag (silver), Co (cobalt), Mo (molybdenum), Mn (manganese), Nb (niobium), Ta (tantalum), W (tungsten), Zn (zinc), Fe (iron), Ir (iridium), and Sc (scandium). In other words, the second layer may contain a hydrated aluminum oxide and oxides and / or hydroxides of one or more metal elements selected from the group consisting of Ni, Cr, Zr, Si, Ti, Au, Ag, Co, Mo, Mn, Nb, Ta, W, Zn, Fe, Ir, and Sc.

[0023] The first and second layers are preferably free of cracks. By forming a crack-free protective film on the base material in this way, the reliability of the surface-treated aluminum material can be further enhanced.

[0024] When a porosity test is performed according to the method specified in JIS H8683-2:2013, the mass loss per unit area of ​​the aluminum material is 0.3 g / dm². 2 The following is preferable: In such an aluminum material, the first layer is sufficiently covered by the second layer. Therefore, by keeping the mass loss in the porosity test within the specified range, the corrosion resistance of the aluminum material can be more easily improved.

[0025] The specific method for the porosity test is as follows: First, 35 mL of phosphoric acid and 20 g of chromic anhydride are dissolved in water to prepare 1 L of test solution. Next, a test piece containing the protective film is taken from the aluminum material, and the area of ​​the protective film on the test piece is measured. After removing any dirt from the surface of the test piece, its mass is measured. Then, the test piece is immersed in the test solution, which is maintained at a temperature of 38°C ± 1°C, for 15 minutes ± 5 seconds.

[0026] After the test specimen has been immersed in the test solution, it is washed with running water, and then with deionized water or distilled water. After the washed specimen is thoroughly dried, its mass is measured.

[0027] The area A (unit: dm²) of the protective coating on the test specimen obtained from the above is... ２ ), the mass m of the test piece before immersion in the test solution １ (Unit: g) and the mass m of the test specimen after immersion in the test solution. ２ Using (unit: g), the mass reduction per unit area δ is calculated based on the following formula (3). Ａ (Unit: g / dm ２ ) can be calculated. δ Ａ = (m １ -m ２ ) / A...(3)

[0028] When the aluminum material is left to stand in an atmosphere of 25°C for 30 minutes, then the ambient temperature is raised to 200°C over 60 minutes, left to stand in the 200°C atmosphere for 30 minutes, and then the ambient temperature is lowered to 25°C over 60 minutes, and this cycle is repeated 100 times, the number of cracks per unit area formed in the protective coating is expressed by the following formula (1): A HC 10 / mm 2 The following is true: A HC = (nx HC +ny HC ) / S HC ... (1)

[0029] However, S in formula (1) above HC This is the field of view (unit: mm²) of a magnified photograph of the surface of the protective coating after the high-temperature cycle test, magnified 500 times. 2 ) and nx HC ny is the number of intersections between the cracks appearing in the enlarged photograph and a first straight line passing through the center of the enlarged photograph and parallel to the horizontal direction of the enlarged photograph. HC This is the number of intersections between the cracks appearing in the enlarged photograph and a second straight line passing through the center of the enlarged photograph and parallel to the vertical direction of the enlarged photograph.

[0030] The protective coating on the aluminum material possessing these characteristics has excellent heat resistance. Therefore, even when the temperature of the aluminum material rises, the occurrence of cracks in the protective coating can be suppressed.

[0031] When the surface-treated aluminum material is subjected to a thermal shock test in which it is left to stand in a 100°C atmosphere for 30 minutes, and then left to stand in a -40°C atmosphere for 30 minutes, and this cycle is repeated 100 times, the number of cracks A per unit area formed in the protective coating is expressed by the following formula (2). HS is 10 / mm 2 The following is preferable: A HS = (nx HS +ny HS ) / S HS ... (2)

[0032] S in formula (2) HS This is the field of view (unit: mm²) of a magnified photograph of the surface of the protective coating after the thermal shock test, magnified 500 times. 2 ) and nx HS ny is the number of intersections between the cracks appearing in the enlarged photograph and a first straight line passing through the center of the enlarged photograph and parallel to the horizontal direction of the enlarged photograph. HS This is the number of intersections between the cracks appearing in the enlarged photograph and a second straight line passing through the center of the enlarged photograph and parallel to the vertical direction of the enlarged photograph.

[0033] The protective coating on the aluminum material possessing these characteristics exhibits excellent heat resistance as well as durability against rapid temperature changes. Therefore, the aluminum material can suppress the occurrence of cracks even when its temperature changes rapidly.

[0034] As mentioned above, the aluminum material exhibits excellent corrosion resistance to corrosive gases and plasma, and can suppress the occurrence of cracks in the protective coating even when the temperature rises. Therefore, the aluminum material is suitable for applications such as cover members provided around the fans of cooking appliances and members for plasma processing equipment. Examples of plasma processing equipment include plasma CVD (chemical vapor deposition) equipment, sputtering equipment, and plasma etching equipment used in semiconductor processes. The aluminum material is particularly suitable for use in upper electrodes, lower electrodes, and shower plates of the aforementioned plasma processing equipment.

[0035] (Method for manufacturing aluminum material) The surface-treated aluminum material is obtained, for example, by forming the first layer on the base material by anodic oxidation treatment of the base material in an electrolyte containing an organic acid, then heating the base material and the first layer at a temperature of 200°C or higher, and then forming the second layer on the first layer. The method for manufacturing the aluminum material will be described in more detail below.

[0036] In producing the surface-treated aluminum material, first, a base material made of aluminum or an aluminum alloy is prepared. The method for manufacturing the base material is not particularly limited, and known methods can be used. For example, the base material may be produced by a method that appropriately combines casting, rolling, and heat treatment. As for the casting method of the base material, either DC casting or continuous casting may be used. Furthermore, the base material may be formed into a desired shape by machining a cast material, forged material, or wrought material.

[0037] Furthermore, in the above manufacturing method, pretreatments such as degreasing, etching, desmatting, polishing, and grinding may be performed on the base material before anodizing, as necessary.

[0038] In the above manufacturing method, the first layer is formed on the base material by subjecting the base material prepared in this manner to an anodic oxidation treatment. In the anodic oxidation treatment, the first layer can be formed on the surface of the base material by DC electrolysis, that is, by passing a DC current between the base material and the counter electrode while the base material and the counter electrode are immersed in an electrolyte solution.

[0039] The electrolyte used in the anodic oxidation process may be an acidic electrolyte containing electrolytes such as sulfuric acid, oxalic acid, or phosphoric acid, or an alkaline electrolyte containing electrolytes such as sodium metaborate. Preferably, the electrolyte used in the anodic oxidation process contains an inorganic electrolyte consisting of inorganic cations such as metal ions or ammonium ions, and one or more anions selected from the group consisting of sulfate ions, phosphate ions, and borate ions. By performing the anodic oxidation process using an electrolyte containing an inorganic electrolyte, a first layer having the desired structure can be formed more easily.

[0040] The current density of the DC current in the anodizing process is, for example, 1 mA / cm². ２ 100mA / cm or more ２ The temperature can be set appropriately from the following range. Furthermore, the electrolyte temperature in the anodizing process can be set appropriately from, for example, a range of 0°C to 40°C.

[0041] The thickness of the first layer formed during the anodizing process is preferably 2 μm or more. By making the thickness of the first layer 2 μm or more, the thickness of the protective film obtained after sealing can be sufficiently increased, thereby further improving the corrosion resistance of the aluminum material.

[0042] In the above manufacturing method, after anodizing treatment, the base material and the first layer are heated to a temperature of 200°C or higher. By heating the first layer under the above specific conditions before forming the second layer on the first layer, it is believed that the internal stress of the first layer can be relieved. Furthermore, by forming the second layer after heating the first layer, the heat resistance of the protective film can be improved, and the occurrence of cracks in the protective film when heated can be suppressed.

[0043] From the viewpoint of more reliably obtaining such effects, it is preferable in the above manufacturing method that the structure of the first layer formed by the anodic oxidation treatment is substantially the same as the structure of the first layer at the time heating is started. In other words, it is preferable to heat the first layer after forming it by the anodic oxidation treatment without performing any treatment that changes the structure of the first layer. From a similar viewpoint, it is even more preferable to heat the first layer after forming it by the anodic oxidation treatment without performing any other treatment. Treatments that change the structure of the first layer include, for example, a treatment that forms cracks in the first layer, a treatment that changes the pore size of the pores in the first layer, and a treatment that deposits a substance different from the substance constituting the first layer into the pores of the first layer.

[0044] From the viewpoint of further improving the heat resistance of the protective coating, the heating temperature of the first layer is preferably 230°C or higher, more preferably 250°C or higher, even more preferably 280°C or higher, and particularly preferably 300°C or higher. If the heating temperature of the first layer is less than 200°C, the relaxation of internal stress in the first layer tends to be insufficient. In this case, the heat resistance of the protective coating becomes insufficient, and there is a risk that cracks may easily occur in the protective coating when the temperature of the aluminum material rises.

[0045] On the other hand, if the heating temperature of the first layer is excessively high, the base material may melt during heating, or the first layer may not be able to keep up with the thermal expansion of the base material, potentially causing cracks to form in the first layer while it is being heated. To avoid these problems and easily form a crack-free first layer, the heating temperature of the first layer is preferably below the melting point of the base material, more preferably below 500°C, even more preferably below 450°C, particularly preferably below 400°C, and most preferably below 380°C. Furthermore, after forming a crack-free first layer on the base material, a crack-free second layer can be easily formed by bringing the first layer into contact with a sealing agent.

[0046] In determining the preferred range of heating temperature for the first layer, the upper and lower limits of the heating temperature for the first layer described above can be arbitrarily combined. For example, the preferred range of heating temperature for the first layer may be 200°C or more and below the melting point of the base material, 230°C or more and below 500°C, 250°C or more and below 450°C, 280°C or more and below 400°C, 300°C or more and below 400°C, or 300°C or more and below 380°C.

[0047] Furthermore, when heating the first layer, heating may be terminated immediately after the temperature of the first layer reaches the desired temperature, or the temperature may be maintained for a certain period of time after reaching the desired temperature. From the viewpoint of sufficiently relieving the internal stress of the first layer and more reliably improving the heat resistance of the aluminum material, the heating time from the start of heating the first layer to the end of heating is preferably 5 minutes or more and less than 12 hours, more preferably 10 minutes or more and less than 12 hours, even more preferably 15 minutes or more and less than 12 hours, and particularly preferably 20 minutes or more and less than 12 hours.

[0048] In the above manufacturing method, after heating the first layer, a sealing agent is brought into contact with the first layer to form a second layer. As the sealing agent, for example, a substance that can react with aluminum oxide to form a hydrated oxide can be used, such as hot water or steam at a temperature of 80°C or higher, or an aqueous solution containing ions of one or more metal elements selected from the group consisting of Ni, Cr, Zr, Si, Ti, Au, Ag, Co, Mo, Mn, Nb, Ta, W, Zn, Fe, Ir, and Sc. When sealing is performed using hot water or steam, a second layer consisting of aluminum hydrated oxide can be formed on the first layer.

[0049] Furthermore, when an aqueous solution containing ions of the metal element is used as a sealing agent, a second layer containing hydrated aluminum oxide and oxides and / or hydroxides of the metal element can be formed on the first layer. The metal element may exist as a metal ion or as a complex ion in the aqueous solution. More specifically, aqueous solutions of metal salts containing the metal element, such as aqueous nickel acetate solution, aqueous cobalt acetate solution, aqueous nickel fluoride solution, aqueous chromate solution, and aqueous silicate solution, can be used as sealing agents.

[0050] From the viewpoint of more easily obtaining aluminum materials with excellent corrosion resistance and heat resistance, it is preferable that the sealing agent be hot water at a temperature of 80°C or higher. When using hot water as the sealing agent, it is even more preferable to form the second layer by contacting the first layer with hot water at 80°C or higher for 10 minutes or more but less than 120 minutes.

[0051] (Example 1) An example of the surface-treated aluminum material and its manufacturing method will be described with reference to Figures 1 to 3. As shown in Figure 1, the surface-treated aluminum material 1 of this example has a base material 2 made of aluminum or an aluminum alloy and a protective film 3 formed on the base material. The protective film 3 has a first layer 31 made of aluminum oxide that covers the base material 2 and a second layer 32 containing hydrated aluminum oxide that covers the first layer 31. When a high-temperature cycle test is performed in which the aluminum material 1 is left to stand in an atmosphere of 25°C for 30 minutes, then the temperature of the atmosphere is raised to 200°C over 60 minutes, left to stand in an atmosphere of 200°C for 30 minutes, and then the temperature of the atmosphere is lowered to 25°C over 60 minutes, and this cycle is repeated 100 times, the number of cracks per unit area formed in the protective film 3 is represented by the following formula (1) A HC 10 / mm 2 The following is true: A HC = (nx HC +ny HC ) / S HC ... (1)

[0052] S in formula (1) HCThis is the field of view (unit: mm²) of the magnified photograph 30 (see Figure 3) showing the surface of the protective coating 3 after the high-temperature cycle test magnified 500 times. 2 ) and nx HC ny is the number of intersection points Ix between the crack C appearing in the enlarged photograph 30 and the first straight line Lx passing through the center 300 of the enlarged photograph 30 and parallel to the horizontal direction of the enlarged photograph 30. HC This is the number of intersection points Iy between the crack C appearing in the enlarged photograph 30 and a second straight line Ly that passes through the center 300 of the enlarged photograph 30 and is parallel to the vertical direction of the enlarged photograph 30.

[0053] Table 1 shows specific examples of aluminum material 1 (test materials A1 to A4). The method for preparing these test materials is as follows, for example.

[0054] [Test materials A1, A3] To prepare test materials A1 and A3, first, an aluminum plate with a thickness of 1 mm and having a chemical composition represented by alloy number A5052 is prepared as the base material 2. This base material 2 is subjected to a pretreatment for anodic oxidation. Specifically, as a pretreatment, the base material 2 is first subjected to an alkaline etching treatment by immersing it in a sodium hydroxide aqueous solution with a concentration of 5 mass% at a temperature of 55°C. After that, the base material 2 is subjected to a desmatt treatment by immersing it in nitric acid with a concentration of 30 mass%.

[0055] After pre-treating the base material 2 as described above, the base material 2 is subjected to DC electrolysis as an anodizing treatment to form the first layer 31 on the surface of the base material 2. The electrolyte used in the anodizing treatment is a 15% by mass aqueous sulfuric acid solution, and the temperature of the electrolyte is 5°C. The current density in the anodizing treatment is 10 mA / cm². ２ The processing time is set to 60 minutes. The first layer 31 formed in this way is a so-called porous anodized film and has a large number of pores 311, as shown in Figure 2. The thickness of the first layer 31 formed by anodic oxidation under the above conditions is approximately 15 μm.

[0056] After anodizing, the base material 2 is heated for 30 minutes in a heating furnace set to the temperature shown in Table 1 to relieve the internal stress of the first layer 31.

[0057] Subsequently, the base material 2 with the first layer 31 is immersed in hot water at 100°C for 60 minutes as a sealing agent to form a second layer 32 made of hydrated aluminum oxide on the first layer 31, and the pores 311 of the first layer 31 are sealed by the second layer 32. Through this process, test materials A1 and A3 shown in Table 1 can be obtained. When the pores 311 of the first layer 31 are sealed under these conditions, the mass loss per unit area of ​​the aluminum material 1 when a sealing degree test is performed according to the method specified in JIS H8683-2:2013 is approximately 0.01 g / dm². 2 This is the result. Furthermore, the first layer 31 and the second layer 32 in test material A1 and test material A3 do not have cracks.

[0058] [Test specimen A2] The method for preparing test specimen A2 is the same as that for test specimen A1, except that the test specimen, after forming the second layer 32 on the first layer 31, is heated in a heating furnace set to a temperature of 200°C for 60 minutes. The first layer 31 and the second layer 32 in test specimen A2 do not have cracks.

[0059] [Test specimen A4] The method for preparing test specimen A4 is the same as that for test specimen A3, except that the test specimen, after forming the second layer 32 on the first layer 31, is heated in a heating furnace set to a temperature of 200°C for 60 minutes. The first layer 31 and the second layer 32 in test specimen A4 do not have cracks.

[0060] [Test Material B1] Test material B1, shown in Table 1, is a test material for comparison with test materials A1 and A3. The method for preparing test material B1 is the same as that for test material A1, except that the second layer is formed without heating after the first layer is formed.

[0061] [Test Material B2] Test material B2, shown in Table 1, is a test material for comparison with test materials A2 and A4. The method for preparing test material B2 is the same as that for test material A2, except that the second layer is formed without heating after the first layer is formed.

[0062] [Number of cracks per unit area formed after high-temperature cycling test] Number of cracks C per unit area formed in the protective coating 3 of test materials A1-A4 and test materials B1-B2 after high-temperature cycling test AHC The calculation method is as follows: First, each test material is placed in a high-temperature cycle tester and a high-temperature cycle test is performed. One cycle in the high-temperature cycle test consists of the first step of leaving the test material in a 25°C atmosphere for 30 minutes, the second step of raising the ambient temperature of the test material from 25°C to 200°C over 60 minutes, the third step of leaving the test material in a 200°C atmosphere for 30 minutes, and the fourth step of lowering the ambient temperature of the test material from 200°C to 25°C over 60 minutes. In the high-temperature cycle test, the above cycle is repeated 100 times.

[0063] Next, the test material is removed from the high-temperature cycle tester after the high-temperature cycle test, and a magnified photograph 30 of the protective coating 3 at 500x magnification is taken using an optical microscope. Figure 3 shows a schematic diagram of a magnified photograph 30 of test material B1 as an example. On this magnified photograph 30, a straight line Lx is drawn passing through the center 300 of the magnified photograph 30 and parallel to the horizontal direction of the magnified photograph 30, and a straight line Ly is drawn passing through the center 300 of the magnified photograph 30 and parallel to the vertical direction of the magnified photograph 30. Then, the number of points nx where the crack C appears in the magnified photograph 30 intersects with the straight line Lx, i.e., the number of points where the crack C crosses the straight line Lx, is determined. HC Count the number of points where crack C intersects line Ly, i.e., the number of points where crack C crosses line Ly, i.e., ny. HC Count them.

[0064] The sum of the number of intersections Ix and Iy obtained in this way is nx. HC +ny HC View area S of enlarged photograph 30 HC (Unit: mm) 2 By dividing by ), the number of cracks C formed in the protective coating 3 after the high-temperature cycle test is calculated as A per unit area. HC (Unit: / mm) 2 Table 1 shows the number of cracks C per unit area formed in the protective coating 3 after high-temperature cycling tests for each test material. HC This indicates.

[0065]

[0066] As shown in Table 1, test materials A1 to A4 are manufactured by heating the first layer on the base material under conditions within the specified range, and then forming the second layer. Therefore, the number of cracks C per unit area formed in the protective coating 3 of test materials A1 to A4 after the high-temperature cycle test is A. HC is 10 / mm 2 The following applies. Therefore, the protective coating 3 of test materials A1 to A4 has excellent heat resistance.

[0067] In contrast, when preparing test specimens B1 and B2, the first layer is formed on the base material, and then the second layer is formed without heating the first layer. Therefore, the number of cracks C per unit area formed in the protective coating 3 of test specimens B1 and B2 after the high-temperature cycle test is A. HC is 10 / mm 2 This is more than the amount. Therefore, the protective coating 3 of test materials B1 to B2 has poor heat resistance.

[0068] (Example 2) This example shows an example in which the aluminum material was subjected to thermal shock and its durability against temperature changes was evaluated. Table 2 shows the aluminum material (test material A5) used in this example. The method for preparing test material A5 is the same as the method for preparing test material A1 in Example 1, except that the heating time of the first layer was changed to 10 minutes.

[0069] [Number of cracks per unit area formed after thermal shock test] Number of cracks C per unit area formed in the protective coating 3 of test material A5 after thermal shock test A HS The calculation method is as follows: First, each test material is placed in a thermal shock testing machine and a thermal shock test is performed. One cycle in the thermal shock test consists of a first step in which the test material is left in a 100°C atmosphere for 30 minutes, and a second step in which the test material is left in a -40°C atmosphere for 30 minutes. The time required for the transition from the first step to the second step, and from the second step to the first step, is only a few seconds. In the thermal shock test, the above cycle is repeated 100 times.

[0070] Next, the test material is removed from the thermal shock testing machine after the thermal shock test, and a magnified photograph of the protective coating 3 is taken at 500x magnification using an optical microscope. Based on this magnified photograph, the number of intersections nx between the cracks and the lines parallel to the horizontal direction of the magnified photograph is determined using the same method as the analysis method for the magnified photograph of the test material after the high-temperature cycle test. HS And the number of intersections between crack C and the line parallel to the vertical direction in the magnified photograph ny HS Count the number of intersections. Then, the sum of the number of intersections nx HS +ny HS Viewing area S of the enlarged photograph HS (Unit: mm) 2 By dividing by ), the number of cracks per unit area formed in the protective coating 3 after the thermal shock test is calculated. HS (Unit: / mm) 2 ) is obtained. Table 2 shows the number of cracks per unit area formed in the protective coating 3 after the thermal shock test on test material A5. HS This indicates.

[0071]

[0072] As shown in Table 2, test material A5 is manufactured by heating the first layer on the base material under the conditions within the specified range, and then forming the second layer. Therefore, the number of cracks C per unit area formed in the protective coating 3 of test material A5 after the thermal shock test is A. HS is 10 / mm 2 The following is true. Therefore, the protective coating 3 of test material A5 also exhibits excellent durability against temperature changes.

[0073] Although embodiments of the surface-treated aluminum material and plasma processing apparatus components have been described above based on Examples 1 and 2, the specific embodiments of the surface-treated aluminum material and plasma processing apparatus components according to the present invention are not limited to those of the examples, and the configuration can be appropriately modified without impairing the spirit of the present invention.

[0074] For example, the surface-treated aluminum material may take the following forms [1] to [4].

[0075] A surface-treated aluminum material comprising: a base material made of aluminum or an aluminum alloy, and a protective film formed on the base material, wherein the protective film is composed of an aluminum oxide and has a first layer covering the base material and a second layer containing a hydrated aluminum oxide and covering the first layer. When a high-temperature cycle test is performed in which the surface-treated aluminum material is left standing in an atmosphere at 25°C for 30 minutes, then the temperature of the atmosphere is raised to 200°C over 60 minutes, left standing in the atmosphere at 200°C for 30 minutes, and then the temperature of the atmosphere is lowered to 25°C over 60 minutes, and this cycle is repeated 100 times, the number A of cracks per unit area formed in the protective film, represented by the following formula (1), HC is 10 / mm 2 or less. The surface-treated aluminum material is as follows. A HC =(nx HC +ny HC ) / S HC ...(1) (In the formula (1), S HC is the field area (unit: mm 2 ) of a magnified photograph obtained by magnifying the surface of the protective film after the high-temperature cycle test 500 times. Nx HC is the number of intersections of the cracks appearing in the magnified photograph and a first straight line passing through the center of the magnified photograph and parallel to the horizontal direction of the magnified photograph. Ny HC is the number of intersections of the cracks appearing in the magnified photograph and a second straight line passing through the center of the magnified photograph and parallel to the vertical direction of the magnified photograph.)

[0076] When a thermal shock test is performed in which the cycle of leaving the surface-treated aluminum material standing in an atmosphere at 100°C for 30 minutes and then leaving it standing in an atmosphere at -40°C for 30 minutes is repeated 100 times, the number A of cracks per unit area formed in the protective film, represented by the following formula (2), HS is 10 / mm 2 or less. The surface-treated aluminum material according to [1] is as follows. A HS =(nx HS +ny HS ) / S HS ...(2) (In the formula (2), S HSThis is the field of view (unit: mm²) of a magnified photograph of the surface of the protective coating after the thermal shock test, magnified 500 times. 2 ) and nx HS ny is the number of intersections between the cracks appearing in the enlarged photograph and a first straight line passing through the center of the enlarged photograph and parallel to the horizontal direction of the enlarged photograph. HS (This is the number of intersections between the cracks appearing in the enlarged photograph and a second straight line passing through the center of the enlarged photograph and parallel to the vertical direction of the enlarged photograph.)

[0077] [3] The surface-treated aluminum material according to [1] or [2], wherein the thickness of the protective film is 5 μm or more and 60 μm or less. [4] The mass loss per unit area when a porosity test is performed according to the method specified in JIS H8683-2:2013 is 0.3 g / dm 2 The surface-treated aluminum material described in any one of the following [1] to [3].

[0078] Furthermore, the plasma processing apparatus member may take the form described in [5] below: A plasma processing apparatus member made of a surface-treated aluminum material as described in any one of [5] [1] to [4].

Claims

1. A surface-treated aluminum material having a base material made of aluminum or an aluminum alloy and a protective film formed on the base material, wherein the protective film is composed of an aluminum oxide and has a first layer covering the base material and a second layer containing hydrated aluminum oxide and covering the first layer. When a high-temperature cycle test is performed in which the surface-treated aluminum material is left standing in an atmosphere of 25°C for 30 minutes, then the temperature of the atmosphere is raised to 200°C over 60 minutes, left standing in an atmosphere of 200°C for 30 minutes, and then the temperature of the atmosphere is lowered to 25°C over 60 minutes, and this cycle is repeated 100 times, the number A per unit area of cracks formed in the protective film, represented by the following formula (1) HC is 10 / mm 2 or less. The surface-treated aluminum material. A HC =(nx HC +ny HC ) / S HC ...(1) (In the formula (1), S HC is the field area (unit: mm 2 ) of a magnified photograph obtained by magnifying the surface of the protective film after the high-temperature cycle test 500 times. Nx HC is the number of intersections of the cracks appearing in the magnified photograph and a first straight line passing through the center of the magnified photograph and parallel to the horizontal direction of the magnified photograph. Ny HC is the number of intersections of the cracks appearing in the magnified photograph and a second straight line passing through the center of the magnified photograph and parallel to the vertical direction of the magnified photograph.) 2. When the surface-treated aluminum material is subjected to a thermal shock test in which it is left to stand in a 100°C atmosphere for 30 minutes, and then left to stand in a -40°C atmosphere for 30 minutes, and this cycle is repeated 100 times, the number of cracks A per unit area formed in the protective coating is expressed by the following formula (2). HS 10 / mm 2 The surface-treated aluminum material according to claim 1 is as follows: A HS = (nx HS +ny HS ) / S HS ... (2) (S in formula (2) above) HS This is the field of view (unit: mm²) of a magnified photograph of the surface of the protective coating after the thermal shock test, magnified 500 times. 2 ) and nx HS ny is the number of intersections between the cracks appearing in the enlarged photograph and a first straight line passing through the center of the enlarged photograph and parallel to the horizontal direction of the enlarged photograph. HS (This is the number of intersections between the cracks appearing in the enlarged photograph and a second straight line passing through the center of the enlarged photograph and parallel to the vertical direction of the enlarged photograph.) 3. The surface-treated aluminum material according to claim 1, wherein the thickness of the protective film is 5 μm or more and 60 μm or less.

4. When the degree of sealing test is performed according to the method specified in JIS H8683-2:2013, the mass loss per unit area is 0.3 g / dm². 2 The surface-treated aluminum material according to claim 1, which is as follows:

5. A component for a plasma processing apparatus, comprising a surface-treated aluminum material as described in any one of claims 1 to 4.

Images