JP2006124728A - Method and device for producing metal material containing active metal, and metal material containing active metal obtained by the production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a metal material containing an active metal in which a compound or an alloy comprising metals easy to be oxidized or metals easy to be evaporated at low temperature can safely be produced at a low cost, to provide a production device therefor, and to provide the metal material containing the active metal produced by the production method. <P>SOLUTION: In a dissolution chamber 7 of a vessel body 2 in a graphite vessel 1 having a buffer cavity 6 on the air side, a lumpy active metal raw material and the other raw material forming a compound or an alloy of the active metal raw material are contained, and while the inside of the buffer cavity 6 is substituted with inert gas, the graphite vessel 2 is held for a fixed time in a temperature range higher than the melting point of the compound or alloy and also lower than the boiling point of the active metal, thereby a compound melt or an alloy melt is formed, and the compound melt or alloy melt is cooled, in order to produce an ingot. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a metal material (compound or alloy) containing a metal that easily oxidizes such as Mg or Ca, or a metal that easily evaporates at a high temperature such as Mg or Ca, a production apparatus, and an active metal obtained by this production method. The present invention relates to a metal material including

Mg, Ca, Ti, etc. are elements that have abundant crustal resource reserves and are characterized by low toxicity to the living body and low environmental impact, and their compounds and alloys are expected to be used in various fields. Yes. However, these metals are easy to oxidize at high temperatures, and especially Mg and Ca have the property of being easily evaporated at high temperatures, so that they are difficult to handle in a powder state, and it is difficult to produce their compounds and alloys.
Examples of this type of metal material include, for example, Mg—Si based thermoelectric materials, Mg—Si based electronic devices, Mg based compounds and alloys represented by Mg based hydrogen storage alloys, Ca—Si based electronic devices, and the like. Examples include Ca-based compounds / alloys such as Ca-based hydrogen storage alloys, Ti-based alloys, and the like, and each conventional manufacturing method will be described below.

[Mg compounds and alloys]
(Mg-Si thermoelectric material)
Bi-Te, Pb-Te, Si-Ge, Fe-Si, Mg-Si, and the like are known as thermoelectric materials used for thermoelectric conversion elements, but Bi, Te, Pb, Ge Such elements as crustal resource reserves are small, and especially Bi and Te have strong toxicity, so it is difficult to deal with large-scale commercialization. In addition, the Fe—Si system has a low figure of merit and is not practical. On the other hand, Mg-Si is low in cost, its constituent elements are low in environmental impact, light weight, high strength, high melting point, and wide operating temperature range, so it is industrially expected as a thermoelectric material. One of the materials to be used. A typical example of the Mg—Si based thermoelectric material is an Mg ₂ Si based compound.

However, since Mg is an active metal and there is a risk of ignition or the like, development of Mg ₂ Si thermoelectric materials has not been advanced so far. Conventionally, as a method for producing the Mg ₂ Si-based compound, the inside of the pressure-resistant heating apparatus is an inert gas atmosphere several times the atmospheric pressure, and Mg and Si are 2: 1 in atomic ratio in the inert gas atmosphere. A mixed powder obtained by adding dopant element powder to Mg and Si powder, or a previously prepared mixed powder composed of Mg ₂ Si powder and dopant element powder is heated to the melting point of Mg ₂ Si (Tm: 1358K or higher, and then cooled. A high-pressure melting method that sometimes produces a Mg ₂ Si-based compound is mentioned.

In addition, as another method for producing the Mg ₂ Si-based compound, Mg and Si powder in which the atomic ratio of Mg and Si is 2: 1 are contained in a graphite crucible in a pressurized container substituted with an inert gas. Examples include a method of containing a mixed powder to which elemental powder has been added, or a previously prepared mixed powder composed of Mg ₂ Si powder and dopant element powder, and melting the mixed powder by heating the graphite crucible at high frequency.

Further, as another method for producing a Mg 2 _Si based compound, so-called mechanical alloying method. In this manufacturing method, Mg and Si powders are weighed so that the atomic ratio of Mg and Si is 2: 1, and these powders are ball milled for a long time (for example, 300 hours) using iron or ceramic balls. mechanically synthesize the Mg 2 _Si powder by performing pulverization, it is to produce a Mg 2 _Si based compound thus obtained Mg 2 _Si powder and heating treatment the dopant element are mixed.

And, as still another method for manufacturing a Mg 2 _Si based compound, a discharge plasma method. In this manufacturing method, a mixing step of mixing Mg and Si powder in which the atomic ratio of Mg and Si is 2: 1 and a dopant element powder are mixed, and the mixed powder obtained in the mixing step is mixed with a melting point of Mg (Tm: In the temperature range of 923 K or more and 1073 K or less, heating and holding for a predetermined time to form Mg ₂ Si by reaction between molten Mg and Si particles, and a dopant element is dissolved in molten Mg, and Mg in the Mg ₂ Si crystal structure Alternatively, an Mg ₂ Si-based compound is produced by substitution and solid solution with a part of Si (see Patent Document 1).

(Mg-Si electronic device)
Mg ₂ Si is a semiconductor having an energy gap of about 0.77 eV, and is expected to be applied to thermophotovoltaic devices. Conventionally, in this device manufacturing method, an Mg ₂ Si film is formed by a solid-phase reaction by exposing a Si substrate to an Mg vapor atmosphere. However, this manufacturing method is expensive and it is difficult to control the Mg deposition process. Therefore, currently, a method of directly forming an Mg ₂ Si film by a vapor deposition process using an Mg—Si compound has been proposed, but for this purpose, a high-purity and inexpensive Mg ₂ Si raw material is required (Non-Patent Document). 1).

(Mg-based hydrogen storage alloy)
Mg-based hydrogen storage alloys typified by Mg ₂ Ni have a large hydrogen storage amount, are lightweight and inexpensive, and thus have a great practical value. However, at present, these alloys do not have an inexpensive manufacturing method due to the same factors as the above Mg ₂ Si-based compounds.

[Ca compounds and alloys]
(Ca-Si electronic device)
Ca ₂ Si, which is a compound of Ca and Si, is a semiconductor having an energy gap of about 1.9 eV, and is expected to be applied to optoelectronic devices. However, Ca is a very active element, which reacts with water vapor at room temperature and also with nitrogen and oxygen at high temperatures, so it requires great care in the production, storage and use of the powder. That is, it is generally difficult to produce Ca ₂ Si using Ca raw material powder such as powder metallurgy or mechanical alloying. Moreover, since the melting point of the Ca ₂ Si compound is (1587K), which is higher than the melting point of Mg ₂ Si (1358K), it is difficult to manufacture by a high pressure melting method. Therefore, at present, Ca ₂ Si-based electronic devices are manufactured by a manufacturing method such as vapor deposition and heat treatment as in the case of Mg-Si-based electronic devices (Non-patent Document 2).

(Ca-based hydrogen storage alloy)
CaNi ₅ which is a compound of Ca and Ni is known to exhibit excellent hydrogen storage characteristics. As a hydrogen storage alloy, this CaNi ₅ -based compound is excellent in ease of initial activation treatment, stable hydrogenation characteristics, poisoning against impure gas, etc., and its practical application is expected. However, CaNi ₅ is difficult to manufacture due to the same factors as Ca ₂ Si.

[Ti alloy]
Ti and its alloys are excellent in corrosion resistance. In particular, since Ti alloys are extremely excellent in specific strength, there is a great demand for application to aircraft. Moreover, since Ti and its alloys are excellent in biocompatibility, they are attracting attention as biomaterials. Furthermore, compounds of Ti and other metals _{(e.g., TiFe, TiCo, TiNi, TiMn} 2, TiCr 2 and TiV etc.) can be expected as a hydrogen storage material. However, since Ti and its alloys have a high melting point, are active and have a high reactivity with oxygen, there is a restriction that they can be produced only by vacuum melting or casting.

  As a technology related to this, for example, an invention relating to “metal oxide polycrystal, thermoelectric material, thermoelectric element and manufacturing method thereof” has been proposed (see Patent Document 4), and metal oxidation containing Mg or Ca is proposed. It is disclosed that the product powder is subjected to spark plasma sintering or hot press sintering.

JP 2002-368291 A Y.Sato, N.Takagi, H.Tatsuoka, H.Kuwabara: International Union of Materials Research Societies-International Conference of Advanced Materials, IUMRS-ICAM2003, C7-11-P42 (2003) H.Mtsui, M.Kramoto, T.Ono, Y.Nose, H.Tatsuoka, H.Kuwabara: J. of Crystal Growth, 237-239 (2002), 2121 Japanese Patent Laid-Open No. 2003-95741

As described above, the manufacturing method of Mg-Si-based thermoelectric materials represented by Mg ₂ Si-based compounds uses Mg powder as a starting material, and therefore there is a risk of explosion of Mg powder during heating and holding. Attention is required. In addition, in the manufacturing by the conventional melting method, the melting point of Mg ₂ Si (Tm: 1358K or higher is maintained by heating, and the boiling point of Mg (Tb: 1370K exists) at a temperature higher than this melting point by 12K. Therefore, the evaporation of Mg cannot be ignored in the temperature range of heating and holding.

  Therefore, as a means for suppressing the evaporation of Mg, a high-pressure inert gas atmosphere must be used, and a heating furnace for heat treatment must have a structure that can withstand the high-pressure atmosphere gas. On the other hand, in the method using high frequency heating, there is a problem that the cost of a product to be obtained increases because the heating device becomes expensive and is not suitable for mass production.

In addition, in the manufacturing method using the mechanical alloying method, there is a problem that the purity of the obtained alloy powder is deteriorated because the balls are gradually worn and mixed as impurities in the powder by a long mixing and grinding operation. Furthermore, in the manufacturing method using the discharge plasma method, a vacuum sintering apparatus is separately required. In addition, Mg-based hydrogen storage alloys typified by Mg ₂ Ni also have a problem that they cannot be produced using an inexpensive apparatus due to the same factors as the above Mg ₂ Si-based compounds.

  That is, conventional production methods for Mg-based compounds / alloys have a risk of explosion, and high-cost processes are used. In addition, Ca and Ti are active metals as well as Mg, and the production of the compounds and alloys thereof is difficult and expensive due to the same factors as the Mg-based compounds and alloys. .

  Moreover, since the manufacturing method described in Patent Document 4 is a method in which a raw material in a powder state is subjected to discharge plasma sintering or hot press sintering, it must be handled as a metal oxide and oxidized such as Mg, Ca and Ti. A simple metal or a metal that easily evaporates at high temperatures such as Mg and Ca cannot be handled alone.

  The present invention was devised in view of the above circumstances, and its purpose is a compound containing a metal that easily oxidizes such as Mg, Ca, or Ti, or a metal that easily evaporates at a high temperature such as Mg or Ca. To provide a metal material containing an active metal that can be produced safely and at low cost, and a metal material containing an active metal that can be produced safely and at low cost by the production method is there.

In order to achieve the above object, the present invention employs the following configuration.
The method for producing a metal material containing an active metal according to the present invention includes a bulk active metal raw material and another raw material for forming a compound or alloy of the active metal raw material in a melting chamber of a graphite container having a buffer cavity on the atmosphere side. And a state in which the inside of the buffer cavity is replaced with an inert gas, and the graphite container is held in a temperature range not lower than the melting point of the compound or the alloy and not higher than the boiling point of the active metal for a certain period of time. A combined financial liquid is produced, and the compound melt or the combined financial liquid is cooled to produce an ingot.

  The active metal may be a metal that easily oxidizes or a metal that easily evaporates at high temperatures. In addition, the graphite container is a container having a bottomed cylindrical body, and is accommodated by introducing an inert gas to the atmosphere side through a semi-sealing punch arranged in the graphite container and defining a space of the container. The buffer cavity and the melting chamber containing the bulk active metal raw material and other raw materials on the bottom side, and heated and held while being cut off from the atmosphere with the inert gas, What is characterized by forming a compound or an alloy is good.

  Furthermore, the graphite container is heated and held in the temperature range to generate the compound melt or the combined financial liquid while replacing the buffer cavity with the inert gas. Is good.

  The apparatus for producing a metal material containing an active metal according to the present invention is a container mainly made of graphite and made of a bottomed cylinder, and is semi-sealed that can be moved in a semi-sealed state along the inner surface of the cylinder of the container body. And a container lid body having an inert gas introduction hole disposed on the upper surface of the container body, and is partitioned on the upper part of the semi-sealing punch via the semi-sealing punch, A buffer cavity for introducing and storing an inert gas, a melting chamber that is partitioned at an upper portion of the semi-sealing punch, and that stores a massive active metal raw material on the bottom side of the container main body, and the container main body and the melting chamber And a heating device for heating and holding.

  In the metal material containing the active metal of the present invention, the active metal raw material is one or more selected from Mg, Ca, Zn, and the other raw materials are Si, Ni, Fe, Co, Mn, Cr, V. It is manufactured by the manufacturing method of the metal material containing the said active metal which is 1 or more types chosen.

The method for producing a metal material containing an active metal according to the present invention, the production apparatus, and the metal material containing an active metal obtained by this production method exhibit the following excellent effects.
In other words, compared to the conventional manufacturing method using powder metallurgy, there is no need to use an active metal such as Mg or Ca in a powder state that is difficult to handle, thus improving the safety during manufacturing and greatly increasing the product cost. Can be reduced.

Further, a graphite container having a dissolution chamber is provided with a buffer cavity for introducing an inert gas to the atmosphere side, and the inside of the buffer cavity is replaced with an inert gas when the graphite container is heated and held in the temperature range. Therefore, it is not necessary to use a vacuum apparatus, the raw material can be directly dissolved under atmospheric pressure, and the product cost can be greatly reduced.
On the other hand, according to the metal material containing an active metal according to the present invention, it is possible to provide a safe and low-cost compound and alloy containing a metal that easily oxidizes such as Mg, Ca, Ti, or a metal that easily evaporates at a high temperature.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings, but the present invention is not limited to this embodiment. The structure of a graphite container used for carrying out the method for producing a metal material containing an active metal according to the present invention will be described with reference to FIG. As shown in the figure, the graphite container 1 used in the manufacturing method of the present embodiment is a container having a bottomed cylindrical shape, and the material of the container body 2 is made of graphite.

  The upper part of the container body (graphite crucible) 2 is open, and the upper end of the opening is closed by a graphite lid 3. The lid 3 is provided with a tubular gas inlet 4 so as to penetrate therethrough. A semi-sealing punch 5 made of graphite is disposed in the middle portion of the container body 2 in the longitudinal direction. The semi-sealing punch 5 can move up and down in the melting chamber 7. By interposing the semi-sealing punch 5, the internal space of the container body 2 can be partitioned into upper and lower spaces.

  That is, the space above the container body 2 is a buffer cavity 6 that is a space for introducing an inert gas from the atmosphere side, and the bottom side that is the lower space of the semi-sealing punch 5 is a melting chamber 7 that can accommodate a raw material. A compartment is formed. The semi-sealing punch 5 has an effect of suppressing the evaporation of the compound melt or the combined financial liquid. Particularly, for example, when the melting point is 923K and the boiling point is 1380K, such as magnesium, it evaporates when the melting point is exceeded. Therefore, by forming a semi-sealed space with the punch 5, this evaporation is suppressed and uniform magnesium of the target component is obtained. Alloys can be manufactured.

  In the manufacturing method of the present embodiment, the active metal raw material and other raw materials forming a compound or alloy with the active metal raw material are accommodated in the melting chamber 7 of the graphite container 1 having the buffer cavity 6 on the atmosphere side. With the inert gas injected into the buffer cavity 6 and replaced with air or the like, the melting chamber 7 of the graphite container 1 is held for a certain period of time in a temperature range above the melting point of the compound or alloy and below the boiling point of each raw material. Thus, a compound melt or a combined financial liquid is produced, and the melt is cooled to produce a polycrystalline ingot.

  Examples of the active metal include metals that easily oxidize such as Mg, Ca, Ti, and Zn, or metals that easily evaporate at high temperatures such as Mg and Ca. Examples of other raw materials that form compounds or alloys with these active metal raw materials include Si, Ni, Fe, Co, Mn, Cr, and V. In the present embodiment, these active metal raw materials are not used in a powdery state that is easy to ignite, but a lump-like one is charged into the melting chamber 7 of the graphite container 1.

In addition, other raw materials that form active metal raw materials and compounds or alloys are preferably used with a small particle size in order to reduce the heating and holding time, particularly in the absence of the risk of ignition or explosion. You may use. On the other hand, since the active metal raw material is sufficiently dissolved at the heating and holding temperature, there is little influence on the holding time of the shape and size of the raw material. For example, when an ingot of an Mg ₂ Si-based compound is produced, the bulk Mg raw material and the irregular granular Si raw material are weighed so as to have an atomic ratio of 2: 1, and the inside of the melting chamber 7 is measured. To charge.

  After completion of the charging of the raw material, a semi-sealing punch 5 is arranged in the container body 2, the opening is closed with a lid 3 having a gas inlet 4, and the dissolution chamber 7 is replaced with Ar. When heating from the outside of the graphite container 1, an inert gas such as argon (Ar) is introduced into the buffer cavity 6 from the gas inlet 4, and the buffer cavity 6 is filled for the entire time of heating / holding and cooling. Is replaced with an inert gas.

  In the present embodiment, Ar is used as the inert gas introduced into the buffer cavity 6, but the present invention is not limited to this, and other gases that do not react with the raw material at a high temperature such as helium (He) may be used. Absent. After replacing the inside of the buffer cavity 6 of the graphite container 1 with an inert gas, the graphite container 1 is housed in a heating furnace and kept for a certain period of time within a temperature range not lower than the melting point of the compound or alloy and not higher than the boiling point of the active metal. To produce a compound melt or a combined financial liquid.

  Here, the heating and holding at a temperature equal to or higher than the melting point of the compound or alloy is for obtaining a uniform compound or alloy by melting the raw material, and the heating and holding at a temperature not higher than the boiling point of the active metal. This is to prevent ignition and explosion due to boiling of the water. Further, since the inner space of the container body 2 is partitioned into upper and lower spaces by the semi-sealing punch 5, the upper space is a buffer cavity 6 filled with an inert gas, and the lower space is a dissolution chamber 7 in which a raw material is dissolved. Are partitioned.

In the present embodiment, an electric furnace is used as a heating means for the graphite container 1, but when the difference between the boiling point of the active metal raw material and the melting point of the compound or alloy is large, for example, induction heating or heating by crucible energization, etc. Other heating means may be used. For example, when producing an ingot of an Mg ₂ Si-based compound, the temperature is in the range of the melting point of Mg ₂ Si (Tm (Mg ₂ Si): 1358K) and the boiling point of Mg (Tb (Mg): 1363K). It was heated to 1361K, by holding at that temperature for 2 hours, to produce a melt of _Mg 2 Si based compound.

  In this heating and holding step, the gas and vapor generated in the melting chamber 7 escape to the outside through a gap between the inner surface of the container body 2 and the outer peripheral surface of the semi-sealing punch 5, but the heating and holding temperature is the active metal (Mg). Therefore, the safety of the graphite container 1 is sufficiently high. On the other hand, the melting chamber 7 is semi-sealed by the semi-sealing punch 5 and the convection of the gas between the melting chamber 7 and the buffer cavity 6 can be greatly suppressed, so that the evaporation amount of the active metal (Mg) to the outside is reduced. Is extremely small, and the change in melt composition is very small. Further, not only in the above heating and temperature maintenance, but also in the subsequent cooling, the Ar gas continues to flow into the buffer cavity 6 so that external oxygen is mixed into the dissolution chamber 7 through the buffer cavity 6. Can be suppressed.

Thus, in the present embodiment, in the graphite container 1, the gap between the inner surface of the container body 2 and the outer peripheral surface of the lid 3 is used as an outlet for releasing the gas and vapor generated in the buffer cavity 6. Further, pores may be formed in the lid 3. Thereafter, the Mg ₂ Si melt is cooled (furnace cooled) to obtain a polycrystalline Mg ₂ Si ingot.

  As described above, according to the manufacturing method of the present embodiment, a massive active metal is used as a raw material, and it is difficult to handle active metals such as Mg and Ca as compared with a manufacturing method using a conventional powder metallurgy method. Therefore, the production safety can be improved and the product cost can be greatly reduced. Moreover, since it is not necessary to use a high-temperature and high-pressure-resistant heating device as compared with the manufacturing method using the conventional high-pressure melting method, the product cost can be reduced.

  Furthermore, compared with the manufacturing method using the conventional mechanical alloying method, since mixing of the impurity in the mixing process by a ball mill can be prevented, a high purity compound can be manufactured. A graphite container 1 having a melting chamber 7 capable of accommodating a raw material on the bottom side is used, with a buffer cavity 6 that can be accommodated by introducing an inert gas to the atmosphere side, and this graphite container 1 is not illustrated. When heating and holding in the above temperature range in an electric furnace, the inside of the buffer cavity 6 is replaced with an inert gas such as Ar, so that it is not necessary to use a vacuum apparatus, and the raw material is directly dissolved under atmospheric pressure. The product cost can be greatly reduced.

  In this embodiment, the graphite container 1 in which a semi-sealed punch is disposed in the bottomed cylindrical container body 2 is used. However, the present invention is not limited to this, and the buffer cavity 6 is provided on the atmosphere side. However, as long as the dissolution chamber 7 is a semi-sealed container, a container of another shape may be used. Moreover, although the graphite container 1 of this embodiment has the buffer cavity 6 of one chamber, it is not restricted to this, You may comprise the container which has the buffer cavity 6 of two or more chambers.

Examples of the present invention will be described in detail below, but the present invention is not limited to these examples.
[Example 1]
Example 1 uses a method for producing a metal material containing an active metal according to the present invention, an example of manufacturing the ingots of Mg 2 _Si based compound. First, the Mg raw material for producing the Mg ₂ Si-based compound and the Si raw material are charged into the melting chamber 7 of the graphite container 1 made of graphite shown in FIG. 1 so that the atomic ratio is 2: 1. Specifically, massive Mg raw material (99.5%) and irregular particulate Si raw material (99.9%) are charged into the melting chamber 7 of the graphite container 1 made of graphite. In this embodiment, the average particle size of Si particles is in the range of 1 to 5 mm. However, in order to reduce the high temperature holding time, it is preferable to use a Si raw material having a small particle size. On the other hand, since the Mg raw material is sufficiently dissolved at the holding temperature, the shape and size of the raw material have little influence on the holding time.

After the completion of the charging of the raw material, the semi-sealing punch 5 is arranged in the container body 2, and the opening is closed with a lid 3 having a gas inlet 4, and the gas inlet 1 is heated when the graphite container 1 is heated. An inert gas such as argon (Ar) is introduced from 4 and the inside of the buffer cavity 6 is replaced with the inert gas during heating / holding and cooling.
Then, _Mg 2 Si melting point _{(Tm (Mg 2 Si):} 1358K) or at the boiling point of Mg (Tb (Mg): 1363K ) was heated to 1361K at the following temperatures, hold 2 hours. In this heating and holding step, only Mg reaching the melting point is melted, and the reaction shown in the following chemical formula 1 (liquid phase-solid phase reaction) proceeds at the interface between the molten Mg and Si in the solid state. Mg ₂ Si melt is obtained.
2Mg (liquid phase) + Si (solid phase) → Mg ₂ Si (liquid phase)

  As described above, in the heating and holding step, the gas and vapor generated in the melting chamber 7 escape to the outside through the gap between the inner surface of the container body 2 and the outer peripheral surface of the semi-sealing punch 5, but the heating and holding temperature is Mg. Therefore, the safety of the graphite container 1 is sufficiently high. On the other hand, the melting chamber 7 is semi-sealed by the semi-sealing punch 5, and the convection of gas between the melting chamber 7 and the buffer cavity 6 can be greatly suppressed, so that the amount of evaporation of Mg to the outside is extremely small, There is also very little change in the melt composition. Furthermore, not only in the above heating and temperature maintenance, but also in the subsequent cooling, by continuously flowing Ar gas into the buffer cavity 6 at a flow rate of 0.5 ml / min, external oxygen passes through the buffer cavity 6. Thus, it is possible to suppress the entry into the melting chamber 7.

Thereafter, the Mg ₂ Si melt is cooled (furnace cooled) to obtain a polycrystalline Mg ₂ Si ingot. A large number of cracks occur in the Mg ₂ Si ingot obtained here. This ingot can be directly used as a vapor deposition raw material, but when applied to a thermoelectric conversion element, it needs to be reworked by sintering after pulverizing it.
The obtained Mg ₂ Si ingot was pulverized and analyzed by X-ray diffraction. As a result, as shown in FIG. 2, the ingot had a substantially simple structure of Mg ₂ Si, and there was very little unreacted Mg and Si. I understand that.
Since the boiling point of Mg is slightly above 12K the melting point of the Mg 2 _Si group compound, produced under atmospheric pressure of Mg 2 _Si based compounds are generally difficult, according to the present embodiment, under atmospheric pressure A polycrystalline ingot of a Mg ₂ Si-based compound could be obtained safely and at low cost.

[Example 2]
Next, an example corresponding to a Ca ₂ Si compound / alloy will be described. Since the basic manufacturing method is substantially the same as the manufacturing method of the first embodiment, a duplicate description will be simplified. In the melting chamber 7, the Ca raw material and the Si raw material are charged so that the atomic ratio is 2: 1. Specifically, massive Ca raw material (99.5%) and irregular particulate Si raw material (99.9%) are charged into the melting chamber 7 of the graphite container 1 made of graphite. In this example, the average particle size of Si particles was in the range of 1 to 5 mm. On the other hand, the average particle diameter of the Ca raw material particles was in the range of (1-3) mm.

After the charging of the raw material is completed, a semi-sealing punch 5 is arranged in the container body 2 and closed by the lid 3, and an inert gas such as argon (Ar) is introduced from the gas inlet 4, when heating and holding In addition, the inside of the buffer cavity 6 is replaced with an inert gas during cooling. First, preheating is performed at a temperature of 673 K for 30 minutes. Heat to 1633 K in the temperature range of the melting point of Ca ₂ Si (Tm (Ca ₂ Si): 1587 K) and the boiling point of Ca (Tb (Ca): 1757 K) and hold for 1 hour. In this heating and holding step, only Ca reaching the melting point or higher is melted, and a reaction (liquid phase-solid phase reaction) shown in the following chemical formula 2 proceeds at the interface between the molten Ca and Si in the solid state. Ca ₂ Si melt is obtained.
2Ca (liquid phase) + Si (solid phase) → Ca ₂ Si (liquid phase)

  As described above, in the heating and holding step, the gas and vapor generated in the melting chamber 7 escape to the outside through the gap between the inner surface of the container body 2 and the outer peripheral surface of the semi-sealing punch 5, and the Ar gas continues to flow. Operations such as dots are the same as those in the first embodiment.

FIG. 1 is a longitudinal sectional view showing the structure of a graphite container having a buffer cavity used in the method for producing a metal material containing an active metal according to the present invention. FIG. 2 is an explanatory diagram showing an X-ray diffraction result of the Mg ₂ Si ingot.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Graphite container 2 Container body 3 Lid 4 Gas inlet 5 Semi-sealing punch 6 Buffer cavity 7 Dissolving chamber

Claims (6)

  In a melting chamber of a graphite container having a buffer cavity on the atmosphere side, a bulk active metal raw material and other raw materials forming a compound or alloy of the active metal raw material are accommodated, and the inside of the buffer cavity is replaced with an inert gas. And maintaining the graphite container in a temperature range not lower than the melting point of the compound or the alloy and not higher than the boiling point of the active metal for a certain period of time to produce a compound melt or a combined liquid, and the compound melt or combined liquid A method for producing a metal material containing an active metal, wherein the ingot is produced by cooling the substrate.   The method for producing a metal material containing an active metal according to claim 1, wherein the active metal is a metal that easily oxidizes or a metal that easily evaporates at a high temperature. The graphite container is a container comprising a bottomed cylindrical body,
Through the semi-sealing punch that is arranged in the graphite container and divides the space of the graphite container, the buffer cavity that introduces and stores the inert gas on the atmosphere side, and the bulk active metal raw material on the bottom side and others The melting chamber for storing the raw material of
The metal material containing an active metal according to claim 1 or 2, wherein a compound or alloy of the active metal raw material is formed by heating and holding while blocking the atmosphere with the inert gas. Production method.   2. The graphite container is heated and held in the temperature range to generate the compound melt or combined liquid while generating the buffer cavity while replacing the inert gas with the inert gas. The manufacturing method of the metal material containing the active metal of any one of Claim 3. A container body which is a container mainly made of graphite and made of a bottomed cylinder;
A semi-sealing punch movable in a semi-sealed state along the inner surface of the cylindrical body of the container body;
It is arranged on the upper surface of the container body, and consists of a container lid body having an inert gas introduction hole,
A buffer cavity that is partitioned at the top of the semi-sealing punch through the semi-sealing punch and introduces and stores an inert gas on the atmosphere side;
A melting chamber that is partitioned at the top of the semi-sealing punch and that contains a massive active metal raw material on the bottom side of the container body;
An apparatus for producing a metal material containing an active metal, comprising: a heating device for heating and holding the container body and the melting chamber. The active metal raw material is one or more selected from Mg, Ca and Zn, and the other raw material is one or more selected from Si, Ni, Fe, Co, Mn, Cr and V. A metal material containing an active metal produced by the method according to claim 4.

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