JP5483157B2 - Method of carburizing tantalum member and tantalum member - Google Patents

Description

  The present invention relates to a method for subjecting a member such as a tantalum container made of tantalum or a tantalum alloy and a lid to carburizing treatment for infiltrating carbon from the surface of the member toward the inside, and a tantalum member obtained by the method. is there.

  Silicon carbide (SiC) is said to be able to realize high temperature, high frequency, withstand voltage and environmental resistance that cannot be achieved with conventional semiconductor materials such as silicon (Si) and barium arsenic (BaAs). It is expected as a semiconductor material for next-generation power devices and high-frequency devices.

  In Patent Document 1, tantalum having a tantalum carbide layer formed on the surface of a single crystal silicon carbide substrate is thermally annealed and a single crystal of silicon carbide is grown on a single crystal silicon carbide substrate. It has been proposed to use the container as a chamber. A single crystal silicon carbide substrate is housed in a tantalum container having a tantalum carbide layer on the surface, and the surface is planarized by thermally annealing the surface or growing a silicon carbide single crystal on the surface, In addition, it has been reported that a single crystal silicon carbide substrate or a silicon carbide single crystal layer with few defects can be formed.

In Patent Document 2 and Patent Document 3, when carbon is infiltrated into the surface of tantalum or tantalum alloy to form tantalum carbide on the surface, Ta ₂ O ₅ which is a natural oxide film on the surface is sublimated and removed. After that, it has been proposed to penetrate carbon.

  However, a specific carburizing method for tantalum containers and tantalum lids has not been studied.

JP 2008-16691 A JP 2005-68002 A JP 2008-81362 A

  An object of the present invention is to provide a carburizing treatment method for a tantalum member that is small in deformation due to carburizing treatment, has good flatness of a flat portion, and can be uniformly carburized, and a tantalum member obtained by the method, and the method. It is to apply the carburizing jig used in the above.

  The carburizing method of the present invention is a method for performing a carburizing process in which carbon is infiltrated from the surface of the member toward the inside of a tantalum member made of tantalum or a tantalum alloy having a flat portion, and the tip portion is tapered. The flat portion is supported by a plurality of support rods formed in the shape of a tantalum member, and the tantalum member is placed in a chamber in which the carbon source is present, and the chamber is depressurized and heated to heat carbon from the carbon source. And a step of carburizing by infiltrating from the surface of the tantalum member.

  In the present invention, the planar portion is supported by a plurality of support rods whose tip portions are formed in a tapered shape, and carburized. Since the tip end portion of the support rod is formed in a tapered shape, the area where the tip end portion of the support rod and the flat portion contact can be reduced. In the portion where the tip of the support bar comes into contact, carbon from the carbon source becomes difficult to carburize or, as will be described later, when the support bar is a carbon source, it may adhere to the flat part. In the present invention, the tip end portion of the support rod is formed in a tapered shape, and the contact area can be reduced, so that the carburizing treatment can be performed uniformly.

  Further, in the present invention, since the flat portion is supported by the plurality of support rods, the deformation of the tantalum member due to the carburizing treatment can be reduced, and the carburizing treatment is performed with the flatness of the flat portion being kept good. be able to.

  In the present invention, it is preferable that the plurality of support rods are arranged in a distributed manner so that the tip portions of the respective support rods support the entire plane portion substantially evenly. Thereby, the deformation | transformation by a carburizing process can be made still smaller and the flatness of a plane part can be made into a further favorable state.

In the present invention, it is preferable that a plurality of support rods are arranged in a dispersed manner, and it is preferable that one or more support rods are supported by an area of 1500 mm ² of the plane portion. Thereby, the deformation | transformation by a carburizing process can be made still smaller and the flatness of a plane part can be made into a further favorable state.

  In the present invention, the support rod preferably functions as a carbon source. When the support rod functions as a carbon source, the carbon source can be disposed near the tantalum member, carbon can be sufficiently supplied to the surface of the tantalum member, and a more uniform carburizing process can be performed.

  Moreover, in this invention, the front-end | tip part of a support bar is formed in the taper shape which a diameter becomes thin as it approaches the tip. For this reason, the area of the front-end | tip part of the support rod which touches the plane part of a tantalum member can be made small. When the support rod is a carbon source, if the area in contact with the flat portion of the tantalum member increases, the flat portion of the tantalum member and the tip of the support rod are fixed, and after the carburizing process, the flat portion of the tantalum member The tip may not be removable. In addition, the carbon concentration is high at the portion where the tip of the support rod contacts, and uniform carburizing may not be possible.

  In the present invention, the chamber preferably functions as a carbon source. Since the chamber covers the periphery of the tantalum member, the entire surface of the tantalum member can be uniformly carburized by the chamber functioning as a carbon source.

  In the case where the support rod or chamber functions as a carbon source, for example, graphite can be used as the carbon source. Since the chamber and the support rod are heat-treated at a high temperature, an isotropic graphite material is preferably used as the graphite. Further, a high-purity graphite material that has been subjected to high-purity treatment using a halogen-containing gas or the like is more preferable. The ash content in the graphite material is preferably 20 ppm or less, more preferably 5 ppm or less. The bulk density is preferably 1.6 or more, and more preferably 1.8 or more. The upper limit of the bulk density is 2.1, for example. As an example of a method for producing isotropic graphite material, petroleum-based or coal-based coke is pulverized to several μm to several tens of μm as a filler, and a binder such as pitch, coal tar, coal tar pitch is added thereto. Knead. The obtained kneaded product is pulverized to several μm to several tens of μm so as to be larger than the pulverized particle size of the raw material filler to obtain a pulverized product. Moreover, it is preferable to remove particles whose particle diameter exceeds 100 μm. The pulverized product is molded, fired and graphitized to obtain a graphite material. Thereafter, high purity treatment is performed using a halogen-containing gas or the like, and the amount of ash in the graphite material is set to 20 ppm or less, whereby contamination of impurity elements from the graphite material into the tantalum member can be suppressed.

  In the present invention, the base of the support bar is supported by the support base, whereby a plurality of support bars are provided on the support base, and the support base is placed on the bottom surface in the chamber. It is preferable that a plurality of support rods are disposed in the chamber. In this case, the support base may function as a carbon source. As the carbon source, graphite such as isotropic graphite material is preferably used as described above.

  The tantalum member in the present invention is preferably a tantalum container having a flat portion and a side wall portion extending from the flat portion in a substantially vertical direction, and an opening is formed by an end portion of the side wall portion. When carburizing a tantalum container by the carburizing method of the present invention, the tantalum container is disposed in the chamber so that the opening of the tantalum container is downward, and the inner flat portion of the tantalum container is supported by a plurality of support rods. It is preferable to do.

  The tantalum member of the present invention is characterized by being carburized by the method of the present invention.

  A jig for carburizing treatment of the present invention is a jig used in the carburizing method of the present invention, and includes a plurality of support bars and a support base that supports the plurality of support bars. Is formed from a graphite material. As described above, it is preferable to use an isotropic graphite material as the graphite material.

  According to the present invention, the deformation of the tantalum member due to the carburizing process is small, the flatness of the flat portion is good, and the carburizing process can be performed uniformly.

Sectional drawing for demonstrating the carburizing method of one Embodiment according to this invention. The top view which shows the position of the support bar in embodiment shown in FIG. The perspective view which shows the tantalum container used in embodiment shown in FIG. The perspective view which shows the tantalum lid | cover used for the tantalum container shown in FIG. Sectional drawing of the tantalum container shown in FIG. Sectional drawing of the tantalum lid | cover shown in FIG. Sectional drawing which shows the state which attached the tantalum cover shown in FIG. 6 to the tantalum container shown in FIG. The top view which shows the position of the support bar in other embodiment according to this invention. The top view which shows the position of the support bar in other embodiment according to this invention. Sectional drawing for demonstrating the carburizing method in a comparative example. The top view which shows the position of the support bar in the comparative example shown in FIG. Sectional drawing which shows the carburizing method of the tantalum lid | cover in further another embodiment according to this invention. Sectional drawing for demonstrating the carburizing process in the Example according to this invention.

  Hereinafter, the present invention will be described with reference to specific embodiments, but the present invention is not limited to the following embodiments.

  FIG. 1 is a cross-sectional view for explaining a carburizing method according to an embodiment of the present invention.

  The tantalum container 1 is disposed in a chamber 3 composed of a chamber container 3a and a chamber lid 3b.

  FIG. 3 is a perspective view showing the tantalum container 1. FIG. 4 is a perspective view showing a tantalum lid 2 made of tantalum or a tantalum alloy used for sealing the tantalum container 1 shown in FIG.

  FIG. 5 is a cross-sectional view showing the tantalum container 1. As shown in FIG. 5, the tantalum container 1 has a flat surface portion 1a and a side wall portion 1b extending from the periphery of the flat surface portion 1a in a direction substantially perpendicular to the flat surface portion 1a. An opening 1d of the tantalum container 1 is formed by the end 1c of the side wall 1b. Here, the “substantially vertical direction” includes a direction of 90 ° ± 20 °.

  6 is a cross-sectional view showing the tantalum lid 2 for sealing the opening 1d of the tantalum container 1 shown in FIG. As shown in FIG. 6, the tantalum lid 2 has a flat surface portion 2a and a side wall portion 2b extending from the flat surface portion 2a in a substantially vertical direction.

  7 is a cross-sectional view showing a state where the tantalum lid 1 shown in FIG. 6 is placed on the end portion 1c of the side wall 1b of the tantalum vessel 1 shown in FIG. As shown in FIG. 7, the side wall 1b of the tantalum container 1 is arranged inside the side wall 2b of the tantalum lid 2, so that the tantalum lid 2 is placed on the tantalum container 1, and the tantalum container 1 is Sealed.

  As shown in FIG. 7, since the side wall 1b of the tantalum container 1 is located inside the side wall 2b of the tantalum lid 2, the inner diameter D inside the side wall 2b of the tantalum lid 2 shown in FIG. It is designed to be slightly larger than the outer diameter d of the tantalum container 1 shown. Usually, the inner diameter D of the tantalum lid 2 is designed to be about 0.1 mm to 4 mm larger than the outer diameter d of the tantalum container 1.

  The tantalum container 1 and the tantalum lid 2 are made of tantalum or a tantalum alloy. The tantalum alloy is an alloy containing tantalum as a main component, and examples thereof include an alloy containing tantalum metal containing tungsten or niobium.

  The tantalum container 1 and the tantalum lid 2 are manufactured by, for example, cutting, drawing from a thin plate, or sheet metal processing. Cutting is a processing method in which a single piece of tantalum metal is cut into a container shape, and a high-precision shape can be manufactured. On the other hand, more metal is cut, resulting in higher material costs. Drawing is a processing method in which one tantalum metal plate is deformed to form a container at a time. When a plate-shaped metal is placed between a die for manufacturing a container and a punch and the punch is pushed toward the die, the material is deformed in a form of being pushed into the die and becomes a container. When the metal plate is pushed in, a wrinkle presser is installed so that the outer metal plate does not wrinkle. Compared with cutting, it is finished in a short time, and the generation of shavings is small, so that the cost and the like can be suppressed. Sheet metal processing is a processing method for forming a container shape by cutting, bending, or welding a single metal plate. Although cost can be reduced in terms of material compared to cutting, the manufacturing time is longer than drawing.

Carburizing each of the tantalum container 1 and the tantalum lid 2 allows carbon to permeate into the interior from the surface and diffuse the carbon into the interior. When carbon penetrates, a Ta ₂ C layer, a TaC layer, or the like is formed. Although a tantalum carbide layer having a high carbon content is formed on the surface, carbon diffuses into the container, so that the surface becomes a tantalum carbide layer having a high tantalum content, whereby the carbon flux can be occluded. Therefore, by performing liquid phase growth or vapor phase growth of silicon carbide in a crucible consisting of a carburized tantalum container and a tantalum lid, carbon vapor generated during the growth process can be occluded in the crucible wall. A silicon atmosphere having a low impurity concentration can be formed therein, defects on the surface of the single crystal silicon carbide can be reduced, and the surface can be planarized. In addition, by annealing the surface of the single crystal silicon carbide substrate in such a crucible, defects can be reduced and the surface can be planarized.

  Returning to FIG. 1, the carburizing process of the present embodiment will be described.

  As shown in FIG. 1, the tantalum container 1 is arranged in a chamber 3 composed of a chamber container 3a and a chamber lid 3b. The tantalum container 1 is disposed in the chamber 3 so that the end 1c of the side wall 1b is downward. The tantalum container 1 is supported in the chamber 3 by supporting the flat portion 1 a inside the tantalum container 1 with a plurality of support rods 6.

As shown in FIG. 1, the tip end portion 6 a of the support bar 6 is formed in a tapered shape whose diameter becomes narrower as it approaches the tip. By forming the tip portion 6a in a tapered shape, the contact area between the tip portion 6a of the support bar 6 and the flat portion 1a of the tantalum container 1 can be reduced. In the present embodiment, the contact area between the tip 6a of the support bar 6 and the flat portion 1a is 0.28 mm ² . The contact area of the tip portion 6a, is preferably within a range of 0.03~12mm ^2, more preferably within the range of 0.1 to 8 mm ^2, more preferably in the range of 0.2 to 5 mm ² It is. If the contact area of the tip portion 6a is too small, the tip portion is likely to be chipped and processing becomes difficult. Also, if the contact area of the tip 6a is too large, when the support rod 6 is made of a graphite material, the flat portion 1a and the tip 6a are fixed during the carburizing process, and the tantalum container 1 is supported by the support bar after the carburizing process. It becomes difficult to remove from 6.

  FIG. 2 is a plan view showing an arrangement state of the support bar 6 with respect to the flat portion 1a. As shown in FIG. 2, in this embodiment, 13 support rods 6 support the planar portion 1 a inside the tantalum container 1.

  As shown in FIG. 2, 13 support rods 6 are arranged in a distributed manner so that the tip portions of the support rods 6 support the flat portion 1a substantially evenly.

  As shown in FIG. 1, the support bar 6 is supported by a support base 5. In the present embodiment, a hole is formed in the support base 5, the lower end of the support bar 6 is inserted into the hole, and the support bar 6 is supported by the support base 5.

  In the present embodiment, the chamber 3, that is, the chamber container 3a and the chamber lid 3b, the support rod 6 and the support base 5 are formed of graphite. Therefore, in the present embodiment, the chamber 3, the support rod 6, and the support base 5 are carbon sources. The chamber 3, the support rod 6, and the support base 5 can be manufactured by cutting.

  It is preferable that the dimension shape of the chamber 3 is set so that the distance between the outer surface of the container 1 and the chamber 3 is substantially uniform as a whole. Thereby, the distance from the chamber which is a carbon source can be made substantially the same in the whole, and it can carburize uniformly throughout the whole.

  In addition, a gap G is preferably formed below the end 1 c of the side wall 1 b of the tantalum container 1. By forming the gap G, carbon can be supplied also from the outside of the tantalum container 1 to the inside of the tantalum container 1. As described above, the gap G is preferably in the range of 2 mm to 20 mm.

  Moreover, the support rod 6 and the support stand 5 which are arrange | positioned inside the tantalum container 1 function also as a carbon source as mentioned above. Therefore, as shown in FIG. 2, the support rods 6 are preferably arranged so as to be distributed almost evenly inside the tantalum container 1.

  As described above, the tantalum container 1 is disposed in the chamber 3, and the carburizing process can be performed by heating the chamber 3 after reducing the pressure in the chamber 3.

  For example, the inside of the chamber 3 can be depressurized by disposing the chamber 3 in the vacuum vessel, covering it, and exhausting the inside of the vacuum vessel. The pressure in the chamber 3 is reduced to 10 Pa or less, for example.

Next, the inside of the chamber 3 is heated to a predetermined temperature. As heating temperature, the range of 1700 degreeC or more is preferable, More preferably, it is the range of 1750 degreeC-2500 degreeC, More preferably, it is the range of 2000 degreeC-2200 degreeC. By heating to such a temperature, the pressure in the chamber 3 is generally about 10 ⁻² Pa to 10 Pa.

  The time for maintaining the predetermined temperature is preferably in the range of 0.1 to 8 hours, more preferably in the range of 0.5 to 5 hours, and further preferably in the range of 1 hour to 3 hours. It is. Since the carburizing speed varies depending on the holding temperature, the holding time is adjusted according to the target carburizing thickness.

  The rate of temperature rise and the rate of cooling are not particularly limited, but generally the rate of temperature rise is preferably in the range of 100 ° C./hour to 2000 ° C./hour, more preferably 300 ° C./hour to 1500 ° C./hour. More preferably, it is 500 ° C./hour to 1000 ° C./hour. The cooling rate is preferably in the range of 40 ° C./hour to 170 ° C./hour, more preferably 60 ° C./hour to 150 ° C./hour, and still more preferably 80 ° C./hour to 130 hours / hour. Cooling is generally performed by natural cooling.

  As described above, in the present embodiment, the planar portion 1a of the tantalum container 1 is supported by the plurality of support rods 6 whose tip portions 6a are tapered, and the carburizing process is performed in this state. Since the planar portion 1a of the tantalum container 1 is supported by the plurality of support rods 6, the deformation of the tantalum container 1 due to the carburizing process is small, and the carburizing process can be performed with the flatness of the planar part 1a being good. Moreover, since the front-end | tip part 6a of the support bar 6 is formed in the taper shape, the whole surface of the tantalum container 1 can be carburized uniformly.

  Moreover, in this embodiment, since the chamber 3, the support rod 6, and the support stand 5 are formed from the graphite material and become a carbon source, the entire surface of the tantalum container 1 can be carburized more uniformly. it can.

  Moreover, in this embodiment, the tantalum container 1 is arrange | positioned in the chamber 3 so that the opening part 1d of the tantalum container 1 may become downward, and the carburizing process is performed in this state. For this reason, it can suppress that the opening part 1d of the tantalum container 1 spreads. Therefore, as shown in FIG. 7, when the tantalum lid 2 is placed on the tantalum container 1, the lid 2 can be placed in a good state, and the hermeticity in the tantalum container 1 can be kept good. For this reason, when thermal annealing or crystal growth is performed inside the tantalum container 1, the silicon vapor can be kept in a good state in the tantalum container 1, and a good crystal state can be obtained.

  The tantalum member that can be carburized by the carburizing method of the present invention is not limited to the tantalum container 1, and for example, the tantalum lid 2 can be carburized.

  FIG. 12 is a cross-sectional view showing a state where the tantalum lid 2 is carburized. As in the embodiment shown in FIG. 1, the flat portion 2a of the tantalum lid 2 is supported by 13 support rods 6 having tip portions 6a formed in a tapered shape, and the inside of the chamber 3 is heated in this state. The surface of the tantalum lid 2 can be carburized.

  Even when the tantalum lid 2 is carburized, the deformation of the tantalum lid 2 due to the carburizing treatment is small, the carburizing treatment can be performed with the flatness of the flat portion 2a being good, and the entire surface of the tantalum lid 2 is uniformly carburized. Can be processed.

  Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the following examples.

Example 1
The tantalum container 1 was carburized using the chamber 3 shown in FIG. As the tantalum container 1, a container having an outer diameter d of 158 mm, a height h of 60 mm, and a thickness t of 3 mm shown in FIG. 3 was used. Therefore, the inner diameter of the flat portion 1a inside the tantalum container 1 is 152 mm, and the area is 18136 mm ² .

In the present embodiment, as shown in FIG. 2, 13 support rods 6 are arranged with respect to the flat portion 1a. Therefore, the flat portion 1a is supported by one support bar 6 per area 1395 mm ² of the flat portion 1a.

  As the chamber 3, a chamber 3 having a cylindrical space with a diameter of 210 mm and a height of 90 mm was used. An isotropic graphite material having a bulk density of 1.8 was used as a material for the chamber container 3a and the chamber lid 3b.

The support rod 6 had a diameter of 6 mm and a length of 75 mm. The length of the tapered portion of the tip portion 6a is 15 mm. Further, the contact area of the tip portion 6a is 0.28 mm ^2. The support rod 6 and the support base 5 were formed from the same isotropic graphite material as the chamber container 3a.

  The gap G below the end 1c of the side wall 1b of the tantalum container 1 was 13 mm.

In this way, the tantalum container 1 was placed in the chamber 3, and the chamber 3 was placed in a SUS vacuum container 8 having a diameter of 800 mm × 800 mm. FIG. 13 is a cross-sectional view showing a state when the chamber 3 is disposed in the vacuum vessel 8. As shown in FIG. 13, a heat insulating material 9 is provided in the vacuum vessel 8, and the chamber 3 is disposed in a space 13 formed in the heat insulating material 9. As the heat insulating material 9, the brand name “DON-1000” (manufactured by Osaka Gas Chemical Co., Ltd., bulk density 0.16 g / cm ³ ) was used. This heat insulating material is a porous heat insulating material obtained by impregnating a pitch-based carbon fiber with a resin and molding, curing, carbonizing, and graphitizing.

  A carbon heater 12 is disposed above the space 13 surrounded by the heat insulating material 9, and the carbon heater 12 is supported by a graphite electrode 11 for flowing a current through the carbon heater 12. By passing an electric current through the carbon heater 12, the space 13 covered with the heat insulating material 9 can be heated.

  The vacuum vessel 8 is formed with an exhaust port 10 for exhausting the inside of the vacuum vessel 8. The exhaust port 10 is connected to a vacuum pump (not shown).

  After the inside of the vacuum vessel 8 was evacuated and the pressure inside the chamber 3 was reduced to 0.1 Pa or less, the inside of the chamber 3 was heated to 2150 ° C. at a temperature increase rate of 710 ° C./hour by the carbon heater 12. Carburizing treatment was performed by maintaining 2150 ° C. for 2 hours. The pressure in the chamber 3 was about 0.5 to 2.0 Pa.

  After the carburizing treatment, it was cooled to room temperature by natural cooling. The cooling time was about 15 hours.

  The roundness and flatness of the flat portion 1a of the tantalum container 1 before and after the carburizing treatment were measured as follows.

  For roundness, the measurement data at each of eight points set at equal intervals around the flat surface 1a, and for flatness, the measurement data at the above eight peripheral points and one point at the center are the three-dimensional measuring machine. Was determined by the deviation from the finally determined average element shape line. Specifically, for roundness, the circular shape was recognized by the average line from the measurement data at each point, and the maximum difference in deviation from the average line at each point was defined as roundness. As for flatness, an average line was recognized from the measurement data at each point, and the maximum difference in deviation from the average line at each point was defined as flatness. The measurement results are shown in Table 1.

(Example 2)
The tantalum container 1 was carburized in the same manner as in Example 1 except that four support rods 6 were dispersed and arranged on the flat portion 1a of the tantalum container 1 as shown in FIG.

  The roundness and flatness of the flat portion 1a of the tantalum container 1 were measured in the same manner as described above before and after the carburizing treatment, and the measurement results are shown in Table 1.

(Example 3)
The tantalum container 1 was carburized in the same manner as in Example 1 except that 17 support rods 6 were dispersed and arranged on the flat portion 1a of the tantalum container 1 as shown in FIG.

  The roundness and flatness of the flat portion 1a of the tantalum container 1 were measured in the same manner as described above before and after the carburizing treatment, and the measurement results are shown in Table 1.

(Comparative Example 1)
As shown in FIG. 10, a cylindrical rod having a diameter of 12 mm and a length of 75 mm was used as the support rod 7 that supports the flat portion 1 a of the tantalum container 1. FIG. 11 is a plan view showing an arrangement state of the support rod 7 with respect to the flat portion 1a. As shown in FIG. 11, one columnar support bar 7 was installed at the center of the flat part 1 a, and the flat part 1 a was supported by the support bar 7. The support bar 7 was also made of an isotropic graphite material in the same manner as the support bar 6. Otherwise, carburizing treatment was performed in the same manner as in Example 1.

  Due to the carburizing process, the tip of the support rod was fixed to the flat surface 1a of the tantalum container 1, and it was difficult to remove after the carburizing process. Therefore, the roundness and flatness of the flat portion 1a could not be measured. However, the tantalum container 1 is deformed more greatly than Example 2 supported by four support rods, and the roundness and It was clear that the flatness was inferior to that of Example 2.

  As is clear from the results of Examples 1 to 3 and Comparative Example 1 described above, according to the present invention, the tantalum container is carburized by supporting the flat portion with a plurality of support rods having tip portions tapered. Thus, the carburizing process can be performed in a state where the deformation of the tantalum container due to the carburizing process is small and the flatness of the flat portion is good.

Further, as is apparent from the results shown in Table 1, Example 1 supported by 13 support rods and Example supported by 17 support rods than Example 2 supported by 4 support rods. 3 is excellent in roundness and flatness. Therefore, it can be seen that the deformation due to the carburizing process can be further reduced by supporting with one or more support rods per area of 1500 mm ² of the flat part, and the flatness of the flat part can be further carburized.

DESCRIPTION OF SYMBOLS 1 ... Tantalum container 1a ... Planar part of tantalum container 1b ... Side wall part of tantalum container 1c ... End part of side wall part of tantalum container 1d ... Opening part of tantalum container 2 ... Lid 2a ... Flat part of lid 2b ... Side wall part of lid DESCRIPTION OF SYMBOLS 3 ... Chamber 3a ... Chamber container 3b ... Chamber lid 5 ... Support stand 6 ... Support rod 6a ... Tip of support rod 7 ... Support rod 8 ... SUS vacuum container 9 ... Heat insulating material 10 ... Exhaust port 11 ... Graphite electrode 12 ... carbon heater 13 ... space covered with insulation

Claims (11)

A method for carburizing a tantalum member made of tantalum or a tantalum alloy having a planar portion so that carbon penetrates from the surface of the member toward the inside,
Disposing the tantalum member in a chamber in which a carbon source is present by supporting the planar portion by a plurality of support rods having tips tapered.
A carburizing treatment method for a tantalum member, comprising: depressurizing and heating the inside of the chamber to infiltrate carbon from the carbon source from the surface of the tantalum member and performing a carburizing treatment.   2. The carburizing of a tantalum member according to claim 1, wherein the plurality of support rods are arranged in a distributed manner so that the tip portions of the support rods substantially uniformly support the entire flat portion. Processing method. 3. The tantalum member carburizing method according to claim 1, wherein the planar portion is supported by one or more support rods per area of 1500 mm ^{2 of the} planar portion.   The tantalum member carburizing method according to claim 1, wherein the support rod functions as the carbon source.   By supporting the base of the support bar on a support base, the plurality of support bars are provided on the support base, and the support base is placed on the bottom surface in the chamber. The method for carburizing a tantalum member according to any one of claims 1 to 4, wherein the plurality of support rods are disposed in the chamber.   6. The method for carburizing a tantalum member according to claim 5, wherein the support base functions as the carbon source.   The carburizing method for a tantalum member according to any one of claims 1 to 6, wherein the chamber functions as the carbon source.   The tantalum member is a tantalum container having the flat portion and a side wall portion extending in a substantially vertical direction from the flat portion, and an opening is formed by an end portion of the side wall portion. Item 8. The method for carburizing a tantalum member according to any one of Items 1 to 7.   The tantalum container is disposed in the chamber so that the opening of the tantalum container is located downward, and the planar portions inside the tantalum container are supported by the plurality of support bars. 8. A method for carburizing a tantalum member according to 8.   A tantalum member that has been carburized by the method according to claim 1. A jig used in the carburizing method according to claim 5 or 6,
A carburizing treatment jig comprising the plurality of support bars and the support base, wherein the support bar and the support base are formed of a graphite material.

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