Graphite electrode, electrode device, electrode, and method for manufacturing quartz glass crucible

Abstract

The present invention is a graphite electrode which is used in arc discharge for manufacturing a quartz crucible, and which is characterized in that the graphite electrode is provided with a graphite electrode main body and a connection part protruding from the graphite electrode main body, and can be connected to an electrode device for energizing the graphite electrode via the connection part, the connection portion is shaped to be connected to the electrode device by being driven in. As a result, the present invention provides a graphite electrode which can be used similarly to conventional graphite electrodes while reducing processing costs.

Description

Technical Field

[0001] The present invention relates to a graphite electrode, an electrode device, an electrode, and a method for manufacturing a quartz glass crucible. In particular, the present invention relates to a graphite electrode, an electrode device, and an electrode formed by connecting the graphite electrode and the electrode device used in arc discharge for manufacturing a quartz glass crucible. Background Art

[0002] Single crystal silicon used as a substrate for single crystal semiconductor materials is mostly manufactured by the so-called Czochralski method, in which polycrystalline silicon is melted in a quartz glass crucible and brought into contact with a seed crystal to allow crystal growth. There are several types of quartz glass crucibles used in the method for manufacturing single crystal silicon, depending on the manufacturing method. In actual use, the following quartz glass crucible is used, which is manufactured by filling silica powder (raw quartz powder) along the inner circumference of a rotatable hollow mold, and heating and melting the silica powder by arc discharge using a graphite electrode while rotating the mold. Regarding the graphite electrode used in the arc discharge for manufacturing the quartz glass crucible, many methods have been disclosed (for example, Patent Documents 1 to 6)

[0003] The graphite electrode is connected to an electrode device (e.g., copper) for conducting electricity (see Patent Documents 1 to 6). As a connection method, an external thread is usually provided on the graphite electrode and an internal thread is provided on the electrode device for screwing, thereby connecting the graphite electrode and the electrode device.

[0004] Figure 2 The schematic diagram shows how to screw the graphite electrode into the electrode assembly. Figure 2 As shown in (a) of FIG. 1 , in the graphite electrode 111 , a connection portion 114 having an external thread shape is provided on a graphite electrode body 112 . The outer shape of the graphite electrode body 112 may have various shapes such as a cylindrical shape.

[0005] In addition, if Figure 2 As shown in (b), the electrode device 121 is formed with a holding portion (a concave coupling portion) 126, and the holding portion 126 is formed with an internal thread shape that can be screwed with the thread of the connecting portion 114 of the graphite electrode 111. The outer shape of the electrode device 121 has various shapes such as a cylindrical shape. The graphite electrode 111 and the electrode device 121 are as shown in FIG. Figure 2 As shown in (c) , the connection portion 114 and the holding portion 126 are screwed together and connected to form the electrode 131 .

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 8-34628

[0009] Patent Document 2: Japanese Patent Application Publication No. 2016-11238

[0010] Patent Document 3: Japanese Patent Application Publication No. 2010-180123

[0011] Patent Document 4: Japanese Patent Application Publication No. 2017-65962

[0012] Patent Document 5: Japanese Patent Application Publication No. 2003-92179

[0013] Patent Document 6: Japanese Patent Application Publication No. 2009-161362 Summary of the invention

[0014] 1. Technical issues to be resolved

[0015] As described above, conventionally, graphite electrodes are connected to electrode devices by screwing, but the screwing method is a major factor in that the processing cost of graphite is high, which increases the production cost of graphite electrodes and, in turn, the production cost of quartz glass crucibles.

[0016] The present invention is made in view of the above situation, and its first purpose is to provide a graphite electrode that reduces processing costs and can be used in the same way as existing graphite electrodes, an electrode device connected to such a graphite electrode, and an electrode formed by connecting such a graphite electrode and an electrode device.

[0017] In addition, a second object of the present invention is to provide a graphite electrode that can be reused in an electrode device with a smaller concave joint portion after being consumed in an electrode device with a larger concave joint portion for connecting to the graphite electrode.

[0018] (II) Technical solution

[0019] The present invention is made to solve the above-mentioned technical problems, and provides a graphite electrode used in arc discharge for manufacturing quartz crucibles, characterized in that the graphite electrode has a graphite electrode body and a connecting portion protruding from the graphite electrode body, and can be connected to an electrode device for energizing the graphite electrode via the connecting portion, and the connecting portion is a shape that is connected to the electrode device by being driven in.

[0020] The graphite electrode of the present invention has a connection portion of a shape connected to an electrode device by driving, so it is easy to process, and thus, the processing cost can be reduced compared to the existing graphite electrode having a screw thread. In addition, the graphite electrode of the present invention can be connected to the electrode device by driving, so when it is actually used to manufacture a quartz crucible, it can be used in the same way as the existing graphite electrode.

[0021] At this time, preferably, the connection portion of the graphite electrode has a shape of a substantially truncated cone in which a diameter on the graphite electrode body side is larger than a diameter on the front end side.

[0022] The graphite electrode having a connection portion of such a shape can be easily connected to the electrode device.

[0023] At this time, preferably, the height of the connection portion is greater than or equal to 10 mm and less than or equal to 40 mm, and has a tapered shape of greater than or equal to 1° and less than or equal to 5° in the height direction.

[0024] The graphite electrode having a connection portion of such a size can be easily connected to the electrode device.

[0025] In addition, the present invention is an electrode device characterized by being capable of holding the above-mentioned graphite electrode and having a hole-shaped holding portion connected to the connecting portion of the graphite electrode.

[0026] Such an electrode device is suitable for connection with the above-mentioned graphite electrode.

[0027] In this case, preferably, a ratio of an inner diameter of the holding portion to an outer diameter of the electrode device is 40% or more and 60% or less.

[0028] If the electrode device has a holding portion of such a size, it can be easily connected to the graphite electrode by driving, and it is easy to adopt a structure in which a coolant flows as the structure inside the electrode device.

[0029] In addition, preferably, the material of the electrode device includes at least one of gold, silver, copper and aluminum.

[0030] Such an electrode device is made of a metal having high ductility and high cooling performance, and therefore can be easily connected to a graphite electrode by driving, and can be easily cooled when used as an electrode.

[0031] In addition, the present invention provides an electrode characterized in that it is an electrode obtained by connecting any one of the above-mentioned graphite electrodes to the electrode device.

[0032] Such an electrode can be connected to the electrode device by driving it in instead of screwing the graphite electrode into it. Such a graphite electrode can reduce the processing cost, and thus the processing cost of the electrode can also be reduced.

[0033] In addition, the present invention is made to solve the above-mentioned technical problems and provides a graphite electrode used in arc discharge for manufacturing quartz glass crucibles, characterized in that the graphite electrode has a connecting portion, which is connected to an electrode device for energizing the graphite electrode via the connecting portion, and the connecting portion has a first connecting portion and a second connecting portion different from the first connecting portion, the second connecting portion is smaller than the first connecting portion, the first connecting portion has a shape that can be connected to the first electrode device, the second connecting portion has a shape that can be connected to the second electrode device, and the second electrode device is smaller than the first electrode device.

[0034] The graphite electrode of the present invention has a second connection portion smaller than the first connection portion. Therefore, after the first connection portion is connected to the first electrode device for arc discharge and consumed, the second connection portion can be connected to the second electrode device for arc discharge again.

[0035] At this time, the first connection part and the second connection part may be in a shape having thread teeth or a cylindrical shape.

[0036] The first connection portion and the second connection portion are preferably configured as a combination of these shapes.

[0037] In addition, the present invention provides an electrode formed by connecting any of the above-mentioned graphite electrodes and the first electrode device, characterized in that the first electrode device is connected via the first connecting portion of the graphite electrode and has a space capable of accommodating the second connecting portion.

[0038] Such an electrode has a space capable of accommodating the second connection portion of the graphite electrode in the electrode device, and therefore the graphite electrode having the second connection portion can be connected without hindrance to perform arc discharge.

[0039] In addition, the present invention provides a method for manufacturing a quartz glass crucible, which uses any of the above-mentioned graphite electrodes and is characterized in that it includes the following steps: connecting the graphite electrode to the first electrode device via the first connecting portion to form a first electrode; manufacturing a quartz glass crucible by arc discharge using the first electrode; removing the graphite electrode consumed by arc discharge using the first electrode from the first electrode device; connecting the graphite electrode removed from the first electrode device to the second electrode device via the second connecting portion to form a second electrode; and manufacturing one or more quartz glass crucibles by arc discharge using the second electrode.

[0040] The graphite electrode of the present invention has a second connection portion that is smaller than the first connection portion as described above, so that after the first connection portion is connected to the first electrode device for arc discharge and consumed, the second connection portion can be connected to the second electrode device for arc discharge again. Therefore, one graphite electrode can be reused to manufacture multiple quartz glass crucibles.

[0041] (III) Beneficial effects

[0042] The graphite electrode according to the first aspect of the present invention has a connection portion that is shaped to be connected to the electrode device by driving, so it is easy to process, and therefore, the processing cost can be reduced compared to the existing graphite electrode with threaded teeth. In addition, the graphite electrode of the present invention can be connected to the electrode device by driving, so in the case of actual use in manufacturing quartz crucibles, it can be used in the same way as the existing graphite electrode. In addition, the electrode device of the present invention is suitable for connection with such a graphite electrode. In addition, the electrode that connects the graphite electrode of the present invention to the electrode device can be connected by driving instead of connecting the graphite electrode to the electrode device by screwing. Such a graphite electrode can reduce the processing cost, so the processing cost as an electrode can also be reduced.

[0043] According to the second aspect of the present invention, the graphite electrode has a second connection portion that is smaller than the first connection portion. Therefore, after the first connection portion is connected to the first electrode device for arc discharge and consumed, the second connection portion can be connected to the second electrode device for arc discharge again. Thus, one graphite electrode can be reused to manufacture multiple quartz glass crucibles. Therefore, the electrode cost can be significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram showing an example of a graphite electrode, an electrode device, and an electrode formed by connecting them according to the first aspect of the present invention.

[0045] Figure 2 This is a schematic diagram showing an example of a conventional graphite electrode, an electrode device, and an electrode formed by connecting them.

[0046] Figure 3 1 is a schematic diagram showing a first embodiment, which is an example of a graphite electrode, an electrode device, and an electrode formed by connecting them according to the second aspect of the present invention.

[0047] Figure 4 1 is a schematic diagram showing a second embodiment, which is an example of a graphite electrode, an electrode device, and an electrode formed by connecting them according to the second aspect of the present invention.

[0048] Figure 51 is a schematic diagram showing a third embodiment, which is an example of the graphite electrode, the electrode device, and the electrode formed by connecting them according to the second aspect of the present invention.

[0049] Figure 6 1 is a schematic diagram showing a fourth embodiment, which is an example of the graphite electrode, the electrode device, and an electrode formed by connecting them according to the second aspect of the present invention.

[0050] Figure 7 This is a flowchart showing an example of a method for manufacturing a quartz glass crucible according to the second aspect of the present invention. DETAILED DESCRIPTION

[0051] The present invention is described in more detail below. In addition, in the present invention, "quartz glass crucible" and "quartz crucible" are synonyms for the same object. In order to respect the priority of the basic application, the terminology is basically maintained in the basic application.

[0052] First, the graphite electrode, the electrode device, and the electrode formed by connecting them according to the first aspect of the present invention will be described.

[0053] The graphite electrode of the first aspect of the present invention is a graphite electrode used in arc discharge for manufacturing quartz crucibles, characterized in that the graphite electrode comprises a graphite electrode body and a connecting portion protruding from the graphite electrode body, and can be connected to an electrode device for energizing the graphite electrode via the connecting portion, and the connecting portion is a shape that is connected to the electrode device by being driven in.

[0054] Hereinafter, specific embodiments of the graphite electrode, the electrode device, and the electrode formed by connecting them according to the present invention will be described with reference to the drawings. Figure 1 Embodiments of the graphite electrode, electrode device, and electrode formed by connecting them according to the present invention are shown.

[0055] Figure 1 The graphite electrode 1 shown in (a) includes a graphite electrode body 2 and a connection portion 4 protruding from the graphite electrode body 2. The graphite electrode 1 can be connected to an electrode device (described later) for supplying electricity to the graphite electrode 1 via the connection portion 4. Figure 1 The connecting portion 4 is connected to the electrode device 5 by punching. The outer shape of the graphite electrode body 2 may be various shapes such as a cylindrical shape.

[0056] in addition, Figure 1 The electrode device 5 shown in (b) can hold the graphite electrode 1 and has a hole-shaped holding portion 6 connected to the connecting portion 4 of the graphite electrode 1 .

[0057] Figure 1(c) shows an electrode 7 formed by connecting the graphite electrode 1 and the electrode device 5. When forming the electrode 7, the connection portion 4 of the graphite electrode 1 and the hole-shaped holding portion 6 of the electrode device 5 are connected. The graphite electrode 1 and the electrode device 5 are connected by matching the shapes of the connection portion 4 and the holding portion 6 and driving them in with external force.

[0058] The graphite electrode 1 of the present invention has the connection portion 4 of a shape connected to the electrode device 5 by driving, so it is easy to process, and thus the processing cost can be reduced compared to the conventional graphite electrode having a screw thread. In addition, the graphite electrode 1 of the present invention can be connected to the electrode device 5 by driving, so when it is actually used to manufacture a quartz crucible, it can be used in the same way as the conventional graphite electrode.

[0059] In the present invention, since the connection portion 4 of the graphite electrode 1 is connected to the hole-shaped holding portion 6 of the electrode device 5 by driving, the inner size of the holding portion 6 needs to be slightly larger than the outer size of the connection portion 4 for the necessity of fixation. However, the shape is not limited as long as the graphite electrode 1 can be fixed by driving.

[0060] The shape of the connection part 4 of the graphite electrode 1 can be set to various shapes such as cylindrical, conical, and polygonal, as long as it can be fixed to the electrode device 5. For example, it can be cylindrical or a truncated cone with a taper. These shapes are also called joint shapes, and the connection part 4 having such a shape is also called a joint. In particular, if Figure 1 As shown in (a), it is preferably a generally truncated cone shape with a larger diameter on the graphite electrode body 2 side than on the front end side. In particular, the connecting portion 4 is preferably 10 mm to 40 mm in height (length), and has a tapered shape of 1° to 5° in the height direction (in addition, Figure 1 The cone angle is exaggerated in FIG. 1 ). Such a truncated cone-shaped connection portion 4 can be easily fixed to the holding portion 6 of the electrode device 5 by driving.

[0061] On the other hand, the ratio of the inner diameter of the holding portion 6 to the outer diameter of the electrode device 5 is preferably 40% or more and 60% or less. The holding portion 6 having such a size can be easily fixed to the connecting portion 4 of the graphite electrode 1 by driving.

[0062] In addition, the electrode device 5 is preferably cooled by circulating a cooling material such as water inside. Thus, it is possible to form an electrode device having a cooling capacity that can withstand the high temperature of arc melting. Thus, from the perspective of the electrode device 5 having a structure in which cooling water circulates inside the electrode device 5, the ratio of the inner diameter of the holding portion 6 to the outer diameter of the electrode device 5 is also preferably 40% or more and 60% or less.

[0063] In addition, the material of the electrode device 5 is preferably at least one of gold, silver, copper and aluminum. These materials are metals with high ductility and high cooling performance, so they are easy to connect to the graphite electrode 1 by driving, and are easy to cool when used as the electrode 7, so they are preferred.

[0064] In addition, in the hole-shaped holding portion 6 of the electrode device 5, the depth of the hole of the holding portion 6 is preferably set to 10 mm or more and 40 mm or less, similarly to the height of the connecting portion 4 of the graphite electrode 1. In addition, the tapered shape of the hole of the holding portion 6 is also preferably set to 1° or more and 5° or less in the depth direction, similarly to the connecting portion 4 of the graphite electrode 1.

[0065] Next, a graphite electrode according to a second aspect of the present invention and an electrode obtained by connecting the graphite electrode and an electrode device will be described.

[0066] The graphite electrode stone of the second aspect of the present invention is a graphite electrode used in arc discharge for manufacturing a quartz glass crucible, wherein the graphite electrode has a connection portion, which is connected to an electrode device for energizing the graphite electrode via the connection portion, and the connection portion has a first connection portion and a second connection portion different from the first connection portion, the second connection portion is smaller than the first connection portion, the first connection portion has a shape that can be connected to the first electrode device, the second connection portion has a shape that can be connected to the second electrode device, and the second electrode device is smaller than the first electrode device. At this time, the first connection portion and the second connection portion can be a shape with thread teeth or a cylindrical shape.

[0067] Hereinafter, specific embodiments of the graphite electrode, the electrode device, and the electrode formed by connecting the graphite electrode and the electrode device according to the second aspect of the present invention will be described by way of example with reference to the first to fourth embodiments. In each embodiment, the same components are described with reference to the same reference numerals.

[0068] [First method]

[0069] Figure 3 The first embodiment of the graphite electrode, electrode device and electrode connected thereto of the present invention is shown. In this embodiment, the first connection portion of the graphite electrode has a threaded shape, and the second connection portion has a cylindrical shape. In addition to the cylindrical shape, the second connection portion may also be a conical shape, a polygonal prism shape, etc., but the cylindrical shape is preferred from the aspects of manufacturing cost, mechanical strength, and connection strength.

[0070] Figure 3 The graphite electrode 11 shown in (a) includes a first connection portion 14 and a second connection portion 16 adjacent to the first connection portion 14 in a graphite electrode body 12. The first connection portion 14 and the second connection portion 16 are connected to an electrode device (described later) for supplying electricity to the graphite electrode 11. Figure 3(b) a first electrode device 51, Figure 3 (e) is connected to the second electrode device 71). In addition, as Figure 3 As shown in (a), the second connection portion 16 is smaller than the first connection portion 14 .

[0071] Furthermore, the first connection portion 14 has a shape that can be connected to the first electrode device 51. In the first embodiment, as Figure 3 As shown in (a), the first connection portion 14 has a thread. Figure 3 The first electrode device 51 shown in (b) is formed with a female coupling portion 54 in the shape of an internal thread. Figure 3 As shown in (c), the graphite electrode 11 and the first electrode device 51 can be connected by screwing the first connection portion 14 and the recessed coupling portion 54 together.

[0072] In addition, if Figure 3 As shown in (b), the first electrode device 51 may have a space 56 capable of accommodating the second connection portion 16 of the graphite electrode 11. Figure 3 As shown in (c), when the first electrode device 51 is connected via the first connection portion 14 using the concave joint 54, the second connection portion 16 of the graphite electrode 11 can be accommodated in the space 56. Therefore, the space 56 is preferably formed slightly larger than the second connection portion 16 of the graphite electrode 11.

[0073] As mentioned above, Figure 3 The electrode (first electrode) 17 shown in (c) is an electrode formed by connecting the graphite electrode 11 and the first electrode device 51, and the first electrode device 51 is connected via the first connecting portion 14 of the graphite electrode 11 and has a space 56 that can accommodate the second connecting portion 16. Using such an electrode (first electrode) 17, arc discharge can be performed to manufacture a quartz glass crucible. After the arc discharge is performed, the size of the graphite electrode body 12 becomes smaller due to consumption. Figure 3 In (d), the graphite electrode body 12a is shown with a reduced size. Figure 3 (d) is not shown, but sometimes the size becomes smaller and the shape of the graphite electrode body 12a changes.

[0074] In addition, the second connecting portion 16 of the graphite electrode 11 has a Figure 3 The shape shown in (e) is connected to the second electrode device 71 which is smaller than the first electrode device 51. In the first embodiment, as shown in Figure 3 As shown in (a) and (d) of FIG. 1 , the second connection portion 16 has a cylindrical shape. Figure 3 The second electrode device 71 shown in (e) is formed with a concave joint portion 76 that can be driven into the second connection portion 16. Figure 3As shown in (f), the graphite electrode 11 and the second electrode assembly 71 can be connected by connecting the second connection portion 16 and the concave joint portion 76. Using the second electrode 18 formed by connecting the graphite electrode 11 and the second electrode assembly 71, arc discharge can be performed to manufacture a quartz glass crucible.

[0075] As described above, generally, the connection between the graphite electrode and the electrode device based on the driving method is used for relatively small graphite electrodes, and the connection between the graphite electrode and the electrode device based on the screwing method is used for relatively large graphite electrodes. Therefore, it is preferred that the first connection portion of the graphite electrode is in the shape of a threaded tooth and the second connection portion is in the first method having a cylindrical shape, but the following second method to fourth method may also be adopted.

[0076] [Second method]

[0077] Figure 4 A second embodiment of the graphite electrode, the electrode device, and the electrode connected thereto according to the present invention is shown. In this embodiment, the first connection portion and the second connection portion of the graphite electrode both have a screw thread shape.

[0078] Figure 4 The graphite electrode 21 shown in (a) includes a first connection portion 24 and a second connection portion 26 adjacent to the first connection portion 24 in a graphite electrode body 22. The first connection portion 24 and the second connection portion 26 are connected to an electrode device (described later) for supplying electricity to the graphite electrode 21. Figure 4 (b) a first electrode device 51, Figure 4 (e) is connected to the second electrode device 81). In addition, Figure 4 As shown in (a), the second connection portion 26 is smaller than the first connection portion 24 .

[0079] Furthermore, the first connection portion 24 has a shape that can be connected to the first electrode device 51. In the second embodiment, as Figure 4 As shown in (a), the first connection portion 24 has a thread. Figure 4 The first electrode device 51 shown in (b) is the same as that in the first embodiment described above. Figure 3 The electrode device shown in (b) is similar to the electrode device shown in FIG. 5 , and a concave coupling portion 54 having an internal thread shape is formed. Figure 4 As shown in (c), the graphite electrode 21 and the first electrode device 51 can be connected by screwing the first connection portion 24 and the recessed coupling portion 54 together.

[0080] In addition, if Figure 4 As shown in (b), the first electrode device 51 may have a space 56 capable of accommodating the second connection portion 26 of the graphite electrode 21. Figure 4As shown in (c), when the first electrode device 51 is connected via the first connection portion 24 using the concave coupling portion 54, the second connection portion 26 of the graphite electrode 21 can be accommodated in the interior of the space 56. Therefore, the space 56 is preferably formed to be slightly larger than the second connection portion 26 of the graphite electrode 21. In addition, in consideration of manufacturing costs, even if the shape of the second connection portion 26 has a thread, the space 56 is preferably a simple shape, such as a cylindrical shape.

[0081] As mentioned above, Figure 4 The electrode (first electrode) 27 shown in (c) is an electrode formed by connecting the graphite electrode 21 and the first electrode device 51, and the first electrode device 51 is connected via the first connecting portion 24 of the graphite electrode 21 and has a space 56 that can accommodate the second connecting portion 26. Using such an electrode (first electrode) 27, arc discharge can be performed to manufacture a quartz glass crucible. After the arc discharge is performed, the size of the graphite electrode body 22 becomes smaller due to consumption. Figure 4 In (d), the graphite electrode body 22a is shown with a reduced size. Figure 4 (d) is not shown, but sometimes the size becomes smaller and the shape of the graphite electrode body 22a changes.

[0082] In addition, the second connecting portion 26 of the graphite electrode 21 has a Figure 4 The shape shown in (e) is connected to the second electrode device 81 which is smaller than the first electrode device 51. In the second embodiment, as shown in Figure 4 As shown in (a) and (d) of FIG. 1 , the second connection portion 26 also has a thread similar to the first connection portion 24. Figure 4 The second electrode device 81 shown in (e) is formed with a female coupling portion 86 having an internal thread shape that can be connected to the second connecting portion 26. Figure 4 As shown in (f), the graphite electrode 21 and the second electrode assembly 81 can be connected by screwing the second connection portion 26 and the concave coupling portion 86. Using the second electrode 28 formed by connecting the graphite electrode 21 and the second electrode assembly 81, arc discharge can be performed to manufacture a quartz glass crucible.

[0083] [Third Method]

[0084] Figure 5 The third embodiment of the graphite electrode, the electrode device and the electrode connected thereto of the present invention is shown. In this embodiment, the first connecting portion and the second connecting portion of the graphite electrode both have a cylindrical shape. In addition to the cylindrical shape, the first connecting portion and the second connecting portion can also be a conical shape, a truncated cone shape, a polygonal prism shape, etc., but from the aspects of manufacturing cost, mechanical strength, and connection strength, a cylindrical shape is preferred.

[0085] Figure 5The graphite electrode 31 shown in (a) includes a first connection portion 34 and a second connection portion 36 adjacent to the first connection portion 34 in a graphite electrode body 32. The first connection portion 34 and the second connection portion 36 are connected to an electrode device (described later) for supplying electricity to the graphite electrode 31. Figure 5 (b) the first electrode device 61, Figure 5 (e) is connected to the second electrode device 71). In addition, as Figure 5 As shown in (a), the second connection portion 36 is smaller than the first connection portion 34 .

[0086] Furthermore, the first connection portion 34 has a shape that can be connected to the first electrode device 61. In the third embodiment, as Figure 5 As shown in (a), the first connection portion 34 is cylindrical. Figure 5 The first electrode device 61 shown in (b) is formed with a concave joint portion 64, which is a shape that can be driven into the cylindrical first connection portion 34 (ie, a cylindrical shape). Figure 5 As shown in (c), the graphite electrode 31 and the first electrode device 61 can be connected by connecting the first connection portion 34 and the recessed coupling portion 64 by hammering or the like.

[0087] In addition, if Figure 5 As shown in (b), the first electrode device 61 may have a space 66 capable of accommodating the second connection portion 36 of the graphite electrode 31. Figure 5 As shown in (c), when the first electrode device 61 is connected via the first connection portion 34 using the concave joint 64, the second connection portion 36 of the graphite electrode 31 can be accommodated in the space 66. Therefore, the space 66 is preferably formed slightly larger than the second connection portion 36 of the graphite electrode 31.

[0088] As mentioned above, Figure 5 The electrode (first electrode) 37 shown in (c) is an electrode formed by connecting the graphite electrode 31 and the first electrode device 61, and the first electrode device 61 is connected via the first connecting portion 34 of the graphite electrode 31 and has a space 66 that can accommodate the second connecting portion 36. Using such an electrode (first electrode) 37, arc discharge can be performed to manufacture a quartz glass crucible. After the arc discharge is performed, the size of the graphite electrode body 32 becomes smaller due to consumption. Figure 5 In (d), the graphite electrode body 32a is shown with a reduced size. Figure 5 (d) is not shown, but sometimes the size becomes smaller and the shape of the graphite electrode body 32a changes.

[0089] In addition, the second connection portion 36 of the graphite electrode 31 has a shape that can be connected to the second electrode device 71 shown in FIG5(e) which is smaller than the first electrode device 61. In the third embodiment, as Figure 5 As shown in (a) and (d) of FIG. 1 , the second connection portion 36 has a cylindrical shape. Figure 5 The second electrode device 71 shown in (e) is formed with a concave joint portion 76 that can be driven into the second connection portion 36. Figure 5 As shown in (f), the graphite electrode 31 and the second electrode assembly 71 can be connected by connecting the second connection portion 36 and the concave joint portion 76. Using the second electrode 38 formed by connecting the graphite electrode 31 and the second electrode assembly 71, arc discharge can be performed to manufacture a quartz glass crucible.

[0090] [Fourth Method]

[0091] Figure 6 The fourth embodiment of the graphite electrode, electrode device and electrode connected thereto of the present invention is shown. In this embodiment, the first connection portion of the graphite electrode has a cylindrical shape, and the second connection portion has a thread. In addition to the cylindrical shape, the first connection portion may also be a truncated cone shape, a polygonal prism shape, etc., but a cylindrical shape is preferred from the aspects of manufacturing cost, mechanical strength, and connection strength.

[0092] Figure 6 The graphite electrode 41 shown in (a) includes a first connection portion 44 and a second connection portion 46 adjacent to the first connection portion 44 in a graphite electrode body 42. The first connection portion 44 and the second connection portion 46 are connected to an electrode device (described later) for energizing the graphite electrode 41. Figure 6 (b) the first electrode device 61, Figure 6 (e) is connected to the second electrode device 81). In addition, Figure 6 As shown in (a), the second connection portion 46 is smaller than the first connection portion 44 .

[0093] Furthermore, the first connection portion 44 has a shape that can be connected to the first electrode device 61. In the fourth embodiment, as Figure 6 As shown in (a), the first connection portion 44 has a cylindrical shape. Figure 6 The first electrode device 61 shown in (b) is the same as that in the third embodiment described above. Figure 5 The electrode device shown in (b) is similar to the electrode device shown in FIG. 1 , and is formed with a concave joint portion 64, which is a shape that can be driven into the cylindrical first connection portion 44 (ie, a cylindrical shape). Figure 6 As shown in (c), the graphite electrode 41 and the first electrode device 61 can be connected by connecting the first connection portion 44 and the recessed coupling portion 64 by hammering or the like.

[0094] In addition, if Figure 6 As shown in (b), the first electrode device 61 may have a space 66 capable of accommodating the second connection portion 46 of the graphite electrode 41. Figure 6As shown in (c), when the first electrode device 61 is connected via the first connection portion 44 using the concave coupling portion 64, the second connection portion 46 of the graphite electrode 41 can be accommodated in the interior of the space 66. Therefore, the space 66 is preferably formed to be slightly larger than the second connection portion 46 of the graphite electrode 41. In addition, in consideration of manufacturing costs, even if the shape of the second connection portion 46 has a thread, the space 66 is preferably a simple shape, such as a cylindrical shape.

[0095] As mentioned above, Figure 6 The electrode (first electrode) 47 shown in (c) is an electrode formed by connecting the graphite electrode 41 and the first electrode device 61, and the first electrode device 61 is connected via the first connecting portion 44 of the graphite electrode 41, and has a space 66 that can accommodate the second connecting portion 46. Using such an electrode (first electrode) 47, arc discharge can be performed to manufacture a quartz glass crucible. After the arc discharge is performed, the size of the graphite electrode body 42 becomes smaller due to consumption. Figure 6 (d) shows a graphite electrode body 42a with a reduced size. Figure 6 (d) is not shown, but sometimes the size becomes smaller and the shape of the graphite electrode body 42a changes.

[0096] In addition, the second connecting portion 46 of the graphite electrode 41 has a Figure 6 The shape shown in (e) is connected to the second electrode device 81 which is smaller than the first electrode device 61. In the fourth embodiment, as shown in Figure 6 As shown in (a) and (d) of FIG. 1 , the second connection portion 46 has a thread. Figure 6 In the second electrode device 81 shown in (e), the Figure 4 The same as the case of (e) is formed with a female coupling portion 86 having an internal thread shape capable of connecting with the second connecting portion 46. Figure 6 As shown in (f), the graphite electrode 41 and the second electrode assembly 81 can be connected by screwing the second connection portion 46 and the concave coupling portion 86. Using the second electrode 48 formed by connecting the graphite electrode 41 and the second electrode assembly 81, arc discharge can be performed to manufacture a quartz glass crucible.

[0097] Next, a method for manufacturing a quartz glass crucible using the graphite electrode of the present invention will be described in more detail. Figure 7 The flow chart is shown in FIG. Figure 3 The first embodiment shown in the figure is described, but when the graphite electrodes of the second to fourth embodiments are used, the connection methods are the same except that the combinations of the screwing method and the driving method are different.

[0098] First, Figure 3The graphite electrode 11 shown in (a) is connected to the Figure 3 The first electrode device 51 shown in (b) is connected to form the first electrode 17 ( Figure 3 (c) Figure 7 Step S11). Figure 3 As shown in (c), the connection here is a screw connection. In addition, at this time, the second connection portion 16 of the graphite electrode 11 is accommodated in the space 56 of the first electrode device 51.

[0099] Next, by arc discharge using the first electrode 17, a quartz glass crucible ( Figure 7 The specific method for manufacturing the quartz glass crucible here is not particularly limited, and as long as the quartz glass crucible using the graphite electrode is manufactured, the graphite electrode and electrode of the present invention can be used.

[0100] Next, the graphite electrode 11 consumed by arc discharge using the first electrode 11 is removed from the first electrode device 51 ( Figure 7 Step S13). At this time, Figure 3 As shown in (d), the graphite electrode body 12a of the first graphite electrode 11 is consumed and reduced in size. In addition, the shape of the graphite electrode body 12a may change due to consumption compared with the graphite electrode body 12 before consumption.

[0101] Next, the removed graphite electrode 11 is connected to the second electrode device 71, but before that, the graphite electrode 11 may be properly cleaned. In addition, the attached matter such as silicon dioxide particles attached to the surface of the graphite electrode body 12a may be removed. In addition, if the deformation of the graphite electrode body 12a becomes a problem, the surface may be processed by cutting.

[0102] Next, Figure 3 The graphite electrode 11 removed from the first electrode device 51 shown in (d) is connected to the second connection portion 16 via the second connection portion 16. Figure 3 The second electrode device 71 shown in (e) is connected to form the second electrode 18 ( Figure 3 (f), Figure 7 Step S14). Figure 3 As shown in (f), the connection here is the punch-in method.

[0103] Next, one or more quartz glass crucibles ( Figure 7After manufacturing one quartz glass crucible, if there is no problem such as insufficient consumption of the graphite electrode 11, the graphite electrode 11 can be directly used for manufacturing the next quartz glass crucible, and multiple quartz glass crucibles can be manufactured. In this case, the quartz glass crucible manufactured using the second electrode 18 can have a smaller diameter than the quartz glass crucible manufactured using the first electrode 17.

[0104] In this way, the graphite electrode of the present invention can be connected to different electrode devices to perform arc discharge respectively, so that a plurality of quartz glass crucibles can be manufactured by repeatedly using one graphite electrode.

[0105] [Example]

[0106] Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples, and various modifications are possible without departing from the technical concept of the present invention.

[0107] (Examples 1-1 to 1-6)

[0108] use Figure 1 The graphite electrode 1, the electrode device 5, and the electrode 7 according to the embodiment of the present invention shown are used to manufacture a quartz crucible.

[0109] First, prepare Figure 1 The graphite electrode 1 shown in (a) is shown in FIG. The graphite electrode body 2 is a cylindrical shape with a diameter of 80 mm and a length of 300 mm, and the connecting portion 4 is set to a roughly truncated cone shape (called a protrusion of the joint). The dimensions of the connecting portion 4 at this time are shown in Table 1. The front end diameter in the table refers to the diameter of the front end of the connecting portion 4, the thick part diameter refers to the diameter of the boundary between the graphite electrode body 2 and the connecting portion 4, and the middle diameter refers to the diameter in the middle of the height (length) from the front end of the connecting portion 4 to the boundary with the graphite electrode body 2.

[0110] [Table 1]

[0111]

[0112] In addition, prepare Figure 1 The electrode device 5 shown in (b).

[0113] Then, if Figure 1 As shown in (c), the graphite electrodes 1 are connected by punching through the connecting portion 4 and the hole-shaped holding portion 6 to form the electrode 7.

[0114] Next, a quartz crucible (diameter 800 mm, 32 inches) was manufactured by arc discharge using such electrode 7 .

[0115] The quartz crucibles of Examples 1-1 to 1-6 can be manufactured in the same manner as a common graphite electrode. In addition, the manufacturing cost of the graphite electrodes of Examples 1-1 to 1-6 is about half of the manufacturing cost of a graphite electrode having a thread.

[0116] (Example 2)

[0117] use Figure 3 The graphite electrode 11 of the first embodiment of the present invention is as follows Figure 7 The quartz glass crucible is manufactured by the process.

[0118] First, prepare Figure 3 The graphite electrode 11 shown in (a) is a graphite electrode 11. The graphite electrode body 12 is a cylindrical shape with a diameter of 80 mm and a length of 300 mm. The first connection part 14 is set to have a threaded shape, and the second connection part 16 is set to a cylindrical shape (called a protrusion of the joint). Figure 3 As shown in (a), the second connection portion 16 is smaller than the first connection portion 14 .

[0119] In addition, prepare Figure 3 The first electrode device 51 shown in (b) is formed with a female coupling portion 54 having an internal thread shape, and has a space 56 adjacent to the female coupling portion 54 .

[0120] Then, if Figure 3 As shown in (c), the graphite electrode 11 is connected to the first electrode device 51 by screwing through the first connecting portion 14 and the concave joint portion 54 to form the first electrode 17 ( Figure 7 Step S11)

[0121] Next, a quartz glass crucible (diameter 800 mm, 32 inches) was manufactured by arc discharge using the first electrode 17 ( Figure 7 Step S12).

[0122] Next, the graphite electrode 11 consumed by the arc discharge is removed from the first electrode device 51 ( Figure 7 Step S13). After the arc discharge, due to consumption, such as Figure 3 As shown in (d), the size of the graphite electrode body 12a is reduced. The size of the graphite electrode body 12a is approximately 60 mm in diameter and 200 mm in height.

[0123] The removed graphite electrode 11 is used in the second electrode device 71 because its size is reduced when used in the first electrode device 51. The removed graphite electrode 11 is subjected to removal of deposits and cleaning.

[0124] Next, the graphite electrode 11 is driven into the second connection portion 16 and the concave connection portion 76. Figure 3 The second electrode device 71 shown in (e) is connected to form Figure 3 (f) shows the second electrode 18 ( Figure 7 Step S14).

[0125] Next, a quartz glass crucible (diameter 600 mm, 24 inches) was manufactured by arc discharge using the second electrode 18 ( Figure 7 Step S15).

[0126] In this way, one graphite electrode 11 can be connected to an electrode assembly different from the original electrode assembly and can be repeatedly used for manufacturing quartz glass crucibles.

[0127] This specification includes the following inventions.

[0128] [1] A graphite electrode used in arc discharge for manufacturing a quartz crucible, characterized in that:

[0129] The graphite electrode includes a graphite electrode body and a connection portion protruding from the graphite electrode body, and can be connected to an electrode device for energizing the graphite electrode via the connection portion.

[0130] The connection portion is shaped to be connected to the electrode device by being driven in.

[0131] [2] The graphite electrode according to [1] above, wherein the connection portion of the graphite electrode has a substantially truncated cone shape in which the diameter of the graphite electrode body side is larger than that of the front end side.

[0132] [3] In the graphite electrode of [2] above, the height of the connection portion is not less than 10 mm and not more than 40 mm, and has a tapered shape of not less than 1° and not more than 5° in the height direction.

[0133] [4] An electrode device capable of holding the graphite electrode described in any one of [1] to [3] above, characterized in that it has a hole-shaped holding portion connected to the connecting portion of the graphite electrode.

[0134] [5] In the electrode device according to [4] above, a ratio of an inner diameter of the retaining portion to an outer diameter of the electrode device is not less than 40% and not more than 60%.

[0135] [6] In the electrode device of [4] or [5] above, the material of the electrode device includes at least one of gold, silver, copper and aluminum.

[0136] [7] An electrode characterized in that it is an electrode formed by connecting the graphite electrode described in any one of [1] to [3] above to the electrode device.

[0137] [8] A graphite electrode used in arc discharge for manufacturing a quartz glass crucible, characterized in that:

[0138] The graphite electrode has a connection portion, and is connected to an electrode device for supplying electricity to the graphite electrode via the connection portion.

[0139] The connecting portion includes a first connecting portion and a second connecting portion different from the first connecting portion,

[0140] The second connecting portion is smaller than the first connecting portion,

[0141] The first connecting portion has a shape that can be connected to the first electrode device,

[0142] The second connection portion has a shape that can be connected to a second electrode device that is smaller than the first electrode device.

[0143] [8] In the graphite electrode of [8] above, the first connection portion and the second connection portion are in a threaded shape or a cylindrical shape.

[0144]

[10] An electrode, which is formed by connecting the graphite electrode of [8] or [9] and the first electrode device, characterized in that:

[0145] The first electrode device is connected via the first connection portion of the graphite electrode and has a space capable of accommodating the second connection portion.

[0146]

[11] A method for manufacturing a quartz glass crucible, using the graphite electrode of [8] or [9], characterized in that it comprises the following steps:

[0147] Connecting the graphite electrode to the first electrode device via the first connecting portion to form a first electrode;

[0148] manufacturing a quartz glass crucible by arc discharge using the first electrode;

[0149] removing the graphite electrode consumed by arc discharge using the first electrode from the first electrode device;

[0150] connecting the graphite electrode removed from the first electrode device to the second electrode device via the second connecting portion to form a second electrode; and

[0151] One or more quartz glass crucibles are manufactured by arc discharge using the second electrode.

[0152] The present invention is not limited to the above-described embodiments. The above-described embodiments are illustrative, and any scheme having substantially the same structure and achieving the same function and effect as the technical concept described in the claims of the present invention is included in the technical scope of the present invention.

Claims

1. A graphite electrode for use in arc discharge for manufacturing a quartz crucible, characterized in that: The graphite electrode includes a graphite electrode body and a connection portion protruding from the graphite electrode body, and can be connected to an electrode device for energizing the graphite electrode via the connection portion. The connection portion is shaped to be connected to the electrode device by being driven in.

2. The graphite electrode according to claim 1, characterized in that The shape of the connection portion of the graphite electrode is a substantially truncated cone shape in which the diameter on the graphite electrode main body side is larger than that on the front end side.

3. The graphite electrode according to claim 2, characterized in that: The connection portion has a height of not less than 10 mm and not more than 40 mm and has a tapered shape of not less than 1° and not more than 5° in a height direction.

4. An electrode device, characterized in that: The graphite electrode according to any one of claims 1 to 3 can be held, and the holding portion has a hole-shaped holding portion connected to the connecting portion of the graphite electrode.

5. The electrode device according to claim 4, characterized in that A ratio of an inner diameter of the holding portion to an outer diameter of the electrode device is not less than 40% and not more than 60%.

6. The electrode device according to claim 4, characterized in that The material of the electrode device includes at least one of gold, silver, copper and aluminum.

7. An electrode, characterized in that: The electrode is formed by connecting the graphite electrode according to any one of claims 1 to 3 to the electrode device.

8. A graphite electrode for use in arc discharge for manufacturing a quartz glass crucible, characterized in that: The graphite electrode has a connection portion, and is connected to an electrode device for supplying electricity to the graphite electrode via the connection portion. The connecting portion includes a first connecting portion and a second connecting portion different from the first connecting portion, The second connecting portion is smaller than the first connecting portion, The first connecting portion has a shape that can be connected to the first electrode device, The second connection portion has a shape that can be connected to a second electrode device, and the second electrode device is smaller than the first electrode device.

9. The graphite electrode according to claim 8, characterized in that: The first connection portion and the second connection portion are in a shape having thread teeth or a cylindrical shape.

10. An electrode, characterized in that: The electrode is formed by connecting the graphite electrode according to claim 8 or 9 and the first electrode device, The first electrode device is connected via the first connection portion of the graphite electrode and has a space capable of accommodating the second connection portion.

11. A method for manufacturing a quartz glass crucible, characterized in that: Using the graphite electrode according to claim 8 or 9 comprises the following steps: Connecting the graphite electrode to the first electrode device via the first connecting portion to form a first electrode; manufacturing a quartz glass crucible by arc discharge using the first electrode; removing the graphite electrode consumed by arc discharge using the first electrode from the first electrode device; connecting the graphite electrode removed from the first electrode device to the second electrode device via the second connecting portion to form a second electrode; and One or more quartz glass crucibles are manufactured by arc discharge using the second electrode.

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