JP2002280625A - Method for manufacturing thermoelectric material and apparatus for manufacturing thermoelectric material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a thermoelectric material having high thermoelectric performance. SOLUTION: A mixture 50, in which a parent material consisting of Bi2 Te3 is mixed with a dispersing agent consisting of SiC, is put into melting chambers 16a and 16b partitioned with a partition wall 14 having a pore 12 and is heated to convert the parent material into a molten state. After that, an inert gas filled in the chambers 16a and 16b is pressure-controlled to make the mixture 50 flow back and forth between the chambers 16a and 16b through the pore 12. Thus, the dispersion of the dispersion agent into the parent material can be facilitated, and the thermoelectric material having high thermoelectric performance can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a thermoelectric material, and more particularly to a thermoelectric material for producing a thermoelectric material in which a dispersion material serving as a phonon scattering center is dispersed in a base material made of a thermoelectric material. The present invention relates to a method for manufacturing a material and a manufacturing apparatus for manufacturing such a thermoelectric material.

[0002]

2. Description of the Related Art Conventionally, in order to improve the thermoelectric performance of a thermoelectric material, it has been proposed to disperse a fine powder (dispersion material) serving as a phonon scattering center in a base material made of a thermoelectric material. As a method for producing such a thermoelectric material, a method has been proposed in which a container containing a base material and a dispersion material in a molten state is rotated and stirred.

[0003]

However, in the method of rotating the container itself, it is necessary to provide a drive mechanism in the manufacturing apparatus, and there is a problem that the manufacturing apparatus is complicated.

[0004] In order to disperse the dispersing material more evenly in the base material, a method of applying ultrasonic vibration to a container and applying ultrasonic vibration to the base material to promote dispersion of the dispersing material is considered. However, when the container itself is rotated, it is difficult to attach the horn, and there is a problem that it is difficult to produce a thermoelectric material having high thermoelectric performance.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made in view of the above-mentioned circumstances, and a manufacturing method for manufacturing a thermoelectric material having high thermoelectric performance and a manufacturing method for manufacturing a thermoelectric material having high thermoelectric performance without using a complicated driving mechanism. It is intended to provide a device.

[0006]

SUMMARY OF THE INVENTION A method for producing a thermoelectric material according to the present invention is a method for producing a thermoelectric material in which a dispersion material serving as a phonon scattering center is dispersed in a base material made of a raw material of the thermoelectric material. And, after putting the base material and the dispersion material in at least one of two melting chambers separated by a partition wall provided with at least one hole, melting the base material, and melting the base material and the dispersion. A melt dispersing step of dispersing the dispersant in the base material by reciprocating a mixture with the material between the melting chambers through the holes.

In the method for producing a thermoelectric material according to the present invention, the mixture is reciprocated between the respective melting chambers through the holes provided in the partition walls separating the two melting chambers. Upon entry, the dispersion of the dispersant into the matrix is promoted. As a result, a thermoelectric material having high thermoelectric performance can be manufactured. Here, the base material is Bi, Sb, Ag, Pb, Ge,
Those containing at least two or more elements among Cu, Sn, As, Se, Te, Fe, Mn, Co, and Si are preferable, and in particular, Bi ₂ T
it is preferable to the e _3. The dispersing materials are B, C, N,
It is preferable to include at least one element among O, Si, P, Ti, Ni, Mo, Zr, Rh, Pd, Ag, W, and Pt.

In the method for producing a thermoelectric material according to the present invention, in the melting and dispersing step, the mixture may be reciprocated between the melting chambers by controlling the pressure of an inert gas filled in each of the melting chambers. . The inert gas is H
Those containing elements having low reactivity with the base material, such as e, Ar, and N ₂ , are preferable.

In the method for producing a thermoelectric material according to the present invention, the melting and dispersing step may be performed while applying ultrasonic vibration to the mixture. In this case, the dispersion of the dispersant in the base material can be further promoted, and a thermoelectric material having higher thermoelectric performance can be manufactured.

In the method for producing a thermoelectric material according to the present invention, a cooling step of cooling the mixture while applying ultrasonic vibration to the mixture may be provided after the melting and dispersing step. In this case, the dispersion of the dispersant in the base material can be promoted during cooling, so that a thermoelectric material having higher thermal performance can be manufactured.

An apparatus for producing a thermoelectric material according to the present invention is a production apparatus for producing a thermoelectric material in which a dispersion material serving as a phonon scattering center is dispersed in a base material made of a raw material of the thermoelectric material,
Separated by a partition provided with holes, two melting chambers for containing a mixture of the base material and the dispersion material, heating means for heating the mixture to melt the base material, and an inert gas in each of the melting chambers. Inert gas supply means for supplying, and gas pressure control for controlling the pressure of the inert gas in each of the melting chambers, and for reciprocating the mixture containing the base material in a molten state between the melting chambers through the holes. Means.

In the thermoelectric material manufacturing apparatus of the present invention, the dispersant is dispersed in the base material by controlling the pressure of the inert gas in each melting chamber and causing the mixture to reciprocate between the melting chambers through the holes. Therefore, it is possible to promote the dispersion of the dispersing material into the base material without providing a complicated driving mechanism for rotating the entire melting chamber, and it is possible to manufacture a thermoelectric material having high thermoelectric performance. Here, the base material is Bi, Sb, Ag, Pb, Ge,
Those containing at least two or more elements among Cu, Sn, As, Se, Te, Fe, Mn, Co, and Si are preferable, and in particular, Bi ₂ T
it is preferable to the e _3. The dispersing materials are B, C, N,
It is preferable to include at least one element of O, Si, P, Ti, Ni, Mo, Zr, Rh, Pd, Ag, W, and Pt. The inert gas preferably contains an element having low reactivity with the base material, such as He, Ar, and N ₂ .

[0013] The apparatus for producing a thermoelectric material according to the present invention may include an ultrasonic vibration applying means for applying ultrasonic vibration to the mixture. This makes it possible to further promote the dispersion of the dispersant in the base material.

[0014]

Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings. FIG.
It is a block diagram showing the outline of the composition of the manufacturing device of the thermoelectric material of this embodiment. The thermoelectric material manufacturing apparatus 100 includes a sealed container 10 for enclosing a mixture 50 of a base material made of Bi ₂ Te _{3 having a} particle size of about 0.01 μm to 1 μm and a dispersion material made of silicon carbide (SiC); A heater 30a for heating 10;
30b, 30c and heater temperature control means 40 for controlling the temperature of the heaters 30a, 30b, 30c.

The closed vessel 10 is provided with a partition wall 1 provided with pores 12.
4 are separated from each other by a heater 30b and heated by a heater 30b.
A gas chamber 20a separated from a and heated by a heater 30a
And the heater 3 separated from the melting chamber 16b by a partition wall 18b.
A gas chamber 20b heated at 0c. Partition wall 18a
Is provided so that gas can move between the melting chamber 16a and the gas chamber 20a, but movement of solids and liquids is prevented. Further, the partition wall 18b is provided between the melting chamber 16b and the gas chamber 2.
0b, it is provided so that gas can move, but movement of solid and liquid is prevented.

Next, a method of manufacturing a thermoelectric material using the manufacturing apparatus 100 will be described. FIG. 2 is a flowchart showing a method for manufacturing a thermoelectric material. In the manufacturing method of the present embodiment, first, the mixture 5 is added to the melting chamber 16a and the melting chamber 16b.
The process starts from the step of inserting 0 (step S10). Then, after the air in the melting chambers 16a, 16b and the gas chambers 20a, 20b is exhausted using a vacuum pump (not shown), the inert gas made of He is filled (step S12). Seal.

Then, the melting chamber 16 is heated by using the heater 30b.
The temperature of the mixture 50 in a and 16b is heated until the melting point of Bi ₂ Te ₃ of the base material becomes 586 ° C. or higher, thereby melting the base material (step S14).

Next, the inert gas in the gas chambers 20a and 20b is heated by using the heaters 30a and 30c to adjust the pressure of the inert gas.
Reciprocating between the melting chambers 16a and 16b (step S
16). For example, when the temperature of the heater 30c is higher than that of the heater 30a, the pressure of the inert gas in the gas chamber 20b becomes higher than the pressure in the gas chamber 20a, and the liquid surface of the mixture 50 in the melting chamber 16b is pressurized. 50 flows into the melting chamber 16a through the pores 12, as shown in FIG. Next, when the temperature of the heater 30b is higher than that of the heater 30c, the pressure of the inert gas in the gas chamber 20a is increased.
Above the pressure inside the melting chamber 16a.
Is pressurized, and the mixture 50 flows into the melting chamber 16b through the pores 12. By controlling the temperature of the heater 30a and the heater 30b in this manner, the mixture 50 can be reciprocated between the melting chamber 16a and the melting chamber 16b. At this time, since the mixture 50 is largely stirred by passing through the pores 12, the dispersion of the dispersant into the molten base material is promoted. Thereafter, the mixture 50 is cooled and solidified (step S18), and the step is ended.

When a thermoelectric material is manufactured by such a method,
Since the dispersion of the dispersant in the molten base material can be promoted, a thermoelectric material having high thermoelectric performance can be manufactured. Further, in the manufacturing apparatus 100, the mixture 50 is reciprocated between the melting chambers 16a and 16b through the pores 12 provided in the partition walls 14 by controlling the pressure of the inert gas to disperse the dispersant in the base material. Dispersion of the dispersion material into the base material can be promoted without providing a complicated drive mechanism that rotates the entire chambers 16a and 16b.

Although the closed container 10 is used in the manufacturing apparatus 100 of this embodiment, an open container that can be opened and closed by a valve may be used. FIG. 3 is a configuration diagram schematically showing the configuration of a thermoelectric material manufacturing apparatus 200 using an open container 210.
The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. The opening / closing of the melting chamber 16a of the open container 210 is controlled by the valve opening / closing control means 220, and the opening / closing is controlled by the leak valve 222a for discharging the inert gas in the melting chamber 16a when the melting chamber 16a is opened, and the valve opening / closing control means 220. A gas supply valve 226a for supplying an inert gas from a cylinder 224 into the melting chamber 16a when opened is provided. The melting chamber 16b is provided with a leak valve 22 that is opened and closed by a valve opening / closing control means 220 to discharge an inert gas in the melting chamber 16b when the melting chamber 16b is opened.
2b, and a gas supply valve 226b for supplying an inert gas from the cylinder 224 to the inside of the melting chamber 16b when the opening and closing are controlled by the valve opening and closing control means 220 to be opened.

In the manufacturing apparatus 200 having such a configuration, in the step S16 shown in FIG.
At 20, the open / close state of each valve is controlled, and the melting chamber 16 a,
The mixture 50 can be stirred by controlling the pressure of the inert gas of 16b. For example, on the melting chamber 16b side, the leak valve 222b is closed and the gas supply valve 226b is opened for a certain time and then closed, and on the melting chamber 16a side, the gas supply valve 226a is closed and the leak valve 222a is closed. Is opened for a certain period of time and then closed, the pressure of the inert gas is increased in the melting chamber 16b, the liquid level of the mixture 50 is increased, and the liquid level is lowered.
Zero flows into the melting chamber 16a through the fine holes 12. Further, on the melting chamber 16a side, the leak valve 222a is closed, the gas supply valve 226a is opened for a certain time and then closed, and on the melting chamber 16b side, the gas supply valve 22a is closed.
6b is closed, and the leak valve 222b is opened for a predetermined time and then closed. In this way, in the melting chamber 16a, the pressure of the inert gas is increased, the liquid level of the mixture 50 is increased, and the liquid level is lowered.
2 and flows into the melting chamber 16b. By doing so, the mixture 50 can be reciprocated between the melting chambers 16a and 16b through the pores 12 provided in the partition wall 14,
Dispersion of the dispersion material into the base material can be promoted without providing a complicated drive mechanism for rotating the entirety of the melting chambers 16a and 16b.

The manufacturing apparatus 200 includes a melting chamber 16a,
A horn 232 connected to the ultrasonic oscillator 230 and provided in the mixture 50 is provided at 16b.
The ultrasonic vibration generated in the mixture 5
0 can be applied. When the step S16 shown in FIG. 2 is performed while applying ultrasonic vibration to the mixture 60 using the horn 232, the dispersion of the dispersion material in the base material can be further promoted, and a thermoelectric material having higher thermoelectric performance can be obtained. Can be manufactured. Further, in step S18 shown in FIG.
When the mixture 50 is cooled while applying ultrasonic vibration to the mixture using the horn 232, the crystal is refined due to the disorder of the solid-liquid interface, and a thermoelectric material having higher thermoelectric performance can be manufactured.

In the manufacturing apparatus of each embodiment, the partition 14
The dispersion material in the mixture 50 contains
It is preferable that the pore size is larger than the maximum particle size of the dispersion material so that the dispersion material can reciprocate between the melting chamber 6a and the melting chamber 16b. Further, if the pore diameter is too large, the stirring effect is reduced. Therefore, it is preferable to set the pore diameter to such an extent that the stirring effect can be maintained. Also, partition 1
4 may be provided with a plurality of pores 12.

[0024]

According to the method for producing a thermoelectric material of the present invention, the mixture is reciprocated between the melting chambers through the holes provided in the partition walls separating the two melting chambers. Dispersion of the dispersant into the base material when entering the melting chamber is promoted. As a result, a thermoelectric material having high thermoelectric performance can be manufactured. Further, in the thermoelectric material manufacturing apparatus of the present invention, the dispersant is dispersed in the base material by controlling the pressure of the inert gas in each melting chamber and reciprocating the mixture between the melting chambers through the holes. Accordingly, it is possible to promote the dispersion of the dispersing material into the base material without providing a complicated driving mechanism for rotating the entire melting chamber, and to manufacture a thermoelectric material having high thermoelectric performance.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing the configuration of a thermoelectric material manufacturing apparatus according to an embodiment.

FIG. 2 is a flowchart illustrating a method for manufacturing a thermoelectric material.

FIG. 3 is a configuration diagram schematically showing a configuration of a thermoelectric material manufacturing apparatus 200 using an open container 210.

[Explanation of symbols]

12 pores, 14 partition walls, 16a, 16b melting chamber, 3
0a, 30b, 30c heater, 40 heater temperature control means, 230 ultrasonic vibrator, 232 horn, 100,
200 Production equipment.

Claims (6)

[Claims] 1. A method for producing a thermoelectric material in which a dispersing material serving as a phonon scattering center is dispersed in a base material made of a raw material of the thermoelectric material, wherein the thermoelectric material is separated by a partition wall provided with at least one hole. After putting the base material and the dispersing material into at least one of the two melting chambers, the base material is melted, and a mixture of the melted base material and the dispersing material is passed through the hole between the melting chambers. A method for producing a thermoelectric material, comprising: a melting and dispersing step of dispersing the dispersant in the base material by reciprocating. 2. The thermoelectric device according to claim 1, wherein in the melting and dispersing step, the mixture is reciprocated between the respective melting chambers by controlling a pressure of an inert gas filled in each of the melting chambers. Material manufacturing method. 3. The method according to claim 1, wherein the melting and dispersing step is performed while applying ultrasonic vibration to the mixture.
Or the method for producing a thermoelectric material according to 2. 4. The thermoelectric material according to claim 1, further comprising a cooling step of cooling the mixture while applying ultrasonic vibration to the mixture after the melting and dispersing step. Production method. 5. A manufacturing apparatus for manufacturing a thermoelectric material in which a dispersion material serving as a phonon scattering center is dispersed in a base material made of a thermoelectric material raw material, wherein the base material is separated from the base material by a partition provided with holes. Two melting chambers for containing the mixture with the dispersing material; heating means for heating the mixture to melt the base material; inert gas supply means for supplying an inert gas into each of the melting chambers; Gas pressure control means for controlling the pressure of the inert gas in the chamber, and reciprocating the mixture containing the base material in a molten state between the melting chambers through the holes. manufacturing device. 6. The apparatus for producing a thermoelectric material according to claim 5, further comprising an ultrasonic vibration applying means for applying ultrasonic vibration to said mixture.