JP2001160633A - Method for pressurizing and extending thermoelectric material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing thermoelectric materials for reducing the fluctuation of thermoelectric characteristics. SOLUTION: This method is provided for pressurizing and extending thermoelectric materials by successively executing an arrangement process for arranging an object 2 to be pressurized formed of thermoelectric materials having thermoelectric chrematistics in a cavity 30 of a molded container 31 and a pressurization and extension method for pressurizing the object 2 to be pressurized in the cavity 30 of the molded container 31 by a pressurizer, and for forming an extender 5 by pressurizing and extending the object 2 to be pressurized. In this arrangement process, when the maximum distance/minimum distance of distances vertically reaching from the outer wall face of the object 2 to be pressurized housed in the cavity 30 of the molded container 31 to the inner wall face of the molded container 31 is set so as to be an α value, the αvalue is determined within 3. The molded container 31 is provided with a positioning part for positioning the object 2 to be pressurized at a set position in the cavity 30. In the arrangement process, it is desired that the object 2 to be pressurized is positioned at the positioning part of the molded container 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drawing a thermoelectric material under pressure by which a thermoelectric material having improved thermoelectric properties can be obtained.

[0002]

2. Description of the Related Art Thermoelectric materials used for thermoelectric devices such as an electronic cooling element, an electronic heating element, and a thermoelectric power generation element include:
It often has anisotropy in thermoelectric properties due to its crystal structure. By aligning the crystal orientation, a high-performance thermoelectric material can be obtained. So, in recent years,
As disclosed in JP-A-10-178218, by subjecting a pressurized object formed of a thermoelectric material to plastic working such as hot upsetting forging or rolling,
A technique has been developed in which a pressing object is stretched to form a stretched body, thereby increasing the orientation of the thermoelectric material, improving the thermoelectric properties of the thermoelectric material, and improving the strength of the thermoelectric material.

According to this publication, plastic deformation causes
It is described that the crystal grains constituting the structure of the thermoelectric material undergo plastic deformation in a flat shape, and the cleavage planes are oriented so as to be perpendicular to the compression direction. As can be seen from the fact that the above publication technique is effective in improving the thermoelectric properties of thermoelectric materials, thermoelectric materials are materials whose thermoelectric properties are sensitive to the crystal orientation inside the material.

[0004]

Means for Solving the Problems In a thermoelectric device using a thermoelectric material, a chip cut from a stretched body formed of the thermoelectric material is generally mounted.
In order to suppress variations in thermoelectric characteristics and to secure sufficient performance of the thermoelectric device, it is preferable that the orientation of each portion obtained in one stretched body does not vary as much as possible.

Further, when a large number of stretched bodies are manufactured by pressure stretching and chips cut from the numerous stretched bodies are mounted on a thermoelectric device, the orientation of each of the manufactured stretched bodies is as small as possible. Preferably it does not vary. That is, when a large number of stretched bodies are produced by pressure stretching, it is preferable that the orientation between the large number of stretched bodies be as similar as possible.

The present invention has been made in view of the above circumstances, and it is a common object to provide a method for manufacturing a thermoelectric material which is advantageous for manufacturing a thermoelectric device with reduced variation in thermoelectric characteristics. is there.

The present inventor has been keenly developing a method for manufacturing a thermoelectric material based on the above-mentioned problems. Then, of the line segments vertically extending from the outer wall surface of the pressurized object accommodated in the cavity of the molding container to the inner wall surface of the molding container, the maximum distance a and the minimum distance b of the line segments located on the same axis are determined. Ratio α
If the object to be pressed is placed in the cavity so that (= a / b) does not exceed 3, the material flow distance when the object to be pressed is plastically deformed by plastic working in the pressing and stretching step. Of the maximum flow distance c and the minimum flow distance b
According to the present invention, it is possible to reduce the variation in the orientation of each part in one stretched body under pressure if the object to be pressed is placed in the cavity so that (= c / d) does not exceed 3. The inventor found and confirmed the results of the test, and completed the manufacturing methods of the first invention and the second invention.

In addition, a positioning portion for positioning the thermoelectric material in the molding container at a set position in the cavity is formed, and the pressing object formed of the thermoelectric material is positioned in the positioning portion of the molding container, and the pressing is performed. If the stretched object formed by pressure-stretching the object is formed, the installation position of the object to be pressurized becomes a fixed position every time, so even when the number of stretched bodies stretched by pressure is large, The inventor has found that the variation in orientation between stretched bodies can be reduced, confirmed by a test,
The manufacturing method of the third invention has been completed.

Further, the first pressing and stretching step is performed in a state where the pressing object formed of the thermoelectric material is arranged closer to one side of the first cavity of the first molding container than the center of the first cavity. Forming a first stretched body, and then using a second molding container having a second cavity longer in the stretching direction than the first cavity, connecting the first stretched body to the second cavity in the second cavity of the second molding vessel. If the second stretched body is formed by performing the second pressure stretching step in this state by disposing the second stretched body in a direction opposite to the one from the center of the cavity, the left and right variation of the material flow in the second stretched body is suppressed, The inventor of the present invention found that the left and right variations in the orientation of the second stretched body could be reduced, confirmed the results of the test, and completed the manufacturing method of the fourth invention.

(1) That is, in the method of stretching a thermoelectric material under pressure according to the first invention, a molding object having a pressing object formed of a thermoelectric material exhibiting thermoelectric properties and a cavity for accommodating the pressing object is provided. A step of preparing a container and an arranging step of arranging the object to be pressurized in the cavity of the molding container; and pressing the object to be pressurized in the cavity of the molding container by a pressurizing body to plastically process the object to be pressurized. And a pressure-stretching step of sequentially performing a pressure-stretching step of forming a stretched body by pressure-stretching in the thermoelectric material, in the disposing step, from the outer wall surface of the pressurized object housed in the cavity of the molding container The maximum distance a such that the ratio α (= a / b) of the maximum distance a and the minimum distance b of the line segments located on the same axis among the line segments that reach the inner wall surface of the molding container vertically does not exceed 3. And pressurized object to define minimum distance b. It is characterized in that arranged in the tee.

[0011] According to the method for stretching a thermoelectric material under pressure according to the first aspect of the invention, in the arranging step, the thermoelectric material accommodated in the cavity of the molding container is vertically extended from the outer wall surface of the object to be pressurized. When the maximum distance / minimum distance is α in a line segment located on the same axis among the line segments reaching the inner wall surface, α is set so as not to exceed 3. For this reason, when the mass is stretched, an excessive difference in the flow state of each part in the cavity is reduced. As a result, the flow phenomenon of the material during the pressure stretching is prevented from being excessively biased by each part of the cavity. That is, the difference in the flow state of the material in each part of the cavity is suppressed as much as possible.

The maximum distance a and the minimum distance b of the line segments that are located on the same axis among the line segments that extend vertically from the outer wall surface of the pressurized object accommodated in the cavity to the inner wall surface of the molding container. Is used. The above-described maximum distance a can be replaced with the maximum flow distance among the material flow distances when the object to be pressed is plastically deformed by plastic working. The above-described minimum distance b can be replaced with the minimum flow distance among the material flow distances.

According to a second aspect of the present invention, there is provided a method for stretching a thermoelectric material under pressure by preparing a pressurized object formed of a thermoelectric material exhibiting thermoelectric properties and a molding container having a cavity for accommodating the pressurized object. And an arranging step of arranging the object to be pressurized in the cavity of the molding container, and pressurizing the object to be pressurized in the cavity of the molding container with a pressurizing body to elongate the object to be pressed by plastic working. And a pressure-stretching step of forming a stretched body, and a pressure-stretching method of the thermoelectric material, which is sequentially performed.
In the arrangement step, the ratio β (= c / d) of the maximum flow distance c to the minimum flow distance b among the material flow distances when the object to be pressed is plastically deformed by the plastic working in the pressure stretching step is 3
The pressurized object is arranged in the cavity so as not to exceed.

[0014] According to the method for stretching a thermoelectric material under pressure according to the second aspect of the present invention, in the arranging step, of the material flow distance when the object to be pressed is plastically deformed by plastic working in the pressing and stretching step, Ratio β between maximum flow distance c and minimum flow distance b
(= C / d) is set so as not to exceed 3. For this reason, when the mass is stretched, an excessive difference in the flow state of each part in the cavity is reduced. As a result, the flow phenomenon of the material during the pressure stretching is prevented from being excessively biased by each part of the cavity. That is, the difference in the flow state of the material in each part of the cavity is suppressed as much as possible.

[0015] (2) The method for stretching a thermoelectric material under pressure according to the third invention is characterized in that a pressurized object formed of a thermoelectric material exhibiting thermoelectric properties, and a molded container having a cavity for accommodating the pressurized object. Preparing the pressurized object, arranging the pressurized object in the cavity of the molding container, and pressurizing the pressurized object in the cavity of the molding container with a pressurizing body to apply the pressurized object by plastic working. In a pressure stretching method of a thermoelectric material, the pressure stretching step of forming a stretched body by pressure stretching is performed in order.
The molding container has a positioning portion for positioning the object to be pressurized at a set position in the cavity, and in the arranging step, the object to be pressurized is positioned in the cavity while the object to be pressurized is positioned in the positioning portion of the molding container. Things.

According to the method for stretching a thermoelectric material under pressure according to the third aspect of the present invention, the molding container has a positioning portion for positioning the object to be pressed with the thermoelectric material at a set position. The object to be pressed is positioned in the cavity while being positioned in the positioning section. As described above, the object to be pressed with the thermoelectric material is positioned at a specific position in the cavity before the pressure stretching. For this reason, even when a large number of objects to be pressed are stretched under pressure, the variation in orientation between a plurality of stretched bodies stretched under pressure is reduced.
That is, the properties of the stretched body stretched under pressure for the first time and 2
Variations between the properties of the stretched body stretched under pressure the third time and the properties of the stretched body stretched under the third pressure are reduced. The same applies to the fourth and subsequent times.

(3) The method for pressure-stretching a thermoelectric material according to a fourth aspect of the present invention provides a method for pressing a thermoelectric material having thermoelectric properties, the method including a pressing object formed of a thermoelectric material and a first cavity for accommodating the pressing object. Preparing a first molding container and a second molding container having a second cavity extending in a direction of extension from the first cavity of the first molding container; A first arranging step of arranging the object closer to one side than the center of the first cavity in the cavity, and pressurizing the object to be pressurized in the first cavity of the first molding container with a pressurizing body to plastically press the object to be pressurized. A first pressure-stretching step of forming a first stretched body by pressure-stretching by processing, and moving the first stretched body in the second cavity of the second molding container in a direction opposite to one of the centers of the second cavities. Second arranging step of arranging the second container, and a second cavity of the second molding container Pressurizing the first stretched body by a pressurizing body, and pressurizing and stretching the first stretched body by plastic working to form a second stretched body. .

[0018] In the method according to the fourth invention, the first pressing and stretching step is performed in a state where the object to be pressurized is arranged closer to one side of the first cavity of the first molding container than the center of the first cavity. Then, a first stretched body is formed. Thereafter, the first stretched body is disposed in the second cavity of the second molding container in a direction opposite to the center of the second cavity in the second cavity, and in that state, the second pressure stretching step is performed to perform the second stretched body. To form
In the method according to the fourth aspect, the stretching direction in the first stretching step and the stretching direction in the second stretching step are opposite to each other. Left and right variations in the material flow are suppressed. Therefore, the left-right variation of the orientation in the second stretched body is suppressed.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Thermoelectric materials according to the first to fourth inventions
In general, the material is anisotropic in crystal performance due to the crystal structure.
Have sex. As the thermoelectric material according to the present invention, for example,
Smuth-tellurium, bismuth-selenium, antimony
Tellurium, antimony-selenium, bismuth-tellurium
Antimony, bismuth-tellurium-selenium
And one type. Specifically, Bi_TwoTe_Three, Bi
_TwoSe_Three, Sb_TwoTe_Three, Sb _TwoSe_ThreeAt least one of
Seeds. P (positive) type thermoelectric device
For example, bismuth-tellurium-antimony system
It is. As an N (negative) type thermoelectric device
For example, bismuth-tellurium, bismuth-tellurium-selenium
Is raised. Even if additives such as silver are added to the thermoelectric material,
good. For purposes such as changing the electrical conductivity of thermoelectric materials
It is.

As the pressing object formed of the thermoelectric material, an aggregate in which thermoelectric material powders are aggregated, a green compact obtained by compressing the thermoelectric material powder, and a green compact obtained by compressing the thermoelectric material powder are fired. A sintered body, a single crystal or polycrystal solidified from a melt of a thermoelectric material, or the like can be employed. As the shape of the object to be pressed, a prismatic shape (including a cube), a cylindrical shape (including a cylindrical shape having a long axial length and a cylindrical shape having a short axial length), and a spherical shape can be adopted.

According to the method of the first invention, in the disposing step, the distance from the outer wall surface of the thermoelectric material accommodated in the cavity of the molding container to the inner wall surface of the molding container perpendicularly, When the maximum distance / minimum distance is α, α
Is set not to exceed 3. According to the method according to the second invention, in the arrangement step, of the material flow distances when the object to be pressed is plastically deformed by the plastic working in the pressure stretching step, the maximum flow distance c and the minimum flow distance b are determined. Ratio β (= c /
Set d) not to exceed 3. Thus, α, β
Is set, an excessive difference in the flow state at each part of the cavity is suppressed, and the flow phenomenon at the time of the pressure stretching is prevented from being excessively biased by each part of the cavity.

Although it depends on the type of thermoelectric material, required thermoelectric properties, required cost, etc., considering the balance of stretchability as much as possible, α and β should not exceed 2.5, or , 2.0, or 1.5, 1.3, or 1.2. Therefore, considering the balance of the stretchability as much as possible, α, β is 1.0 to
2.0 range, 1.0-1.5 range, 1.0-1.4
, And a range of 1.0 to 1.3. In order to balance stretchability during pressure stretching, α, β
Is preferably closer to 1 as long as it does not exceed 3.

The molding container may have a positioning portion for positioning the object to be pressurized at a set position in the cavity so that α and β do not exceed 3.

The positioning section and the positioning section according to the third aspect of the present invention are not particularly limited as long as the object to be pressurized can be positioned at a fixed position when the pressurized object is set in the cavity of the molding container. And at least one of a positioning recess provided in the cavity of the molding die and a positioning projection (including a pin) provided in the cavity of the molding die.

According to the pressure stretching method according to the third aspect of the present invention, even if the object to be pressed is not necessarily placed in the center area of the cavity of the molding die, that is, the positioning portion is located at a position biased to the cavity of the molding die. Even if it is provided, the installation location of the object to be pressed is fixed in the cavity of the mold. Therefore, in the first stretched body, the second stretched body, the third stretched body, and the like, the state of the pressure stretching is basically the same. The same applies to the fourth and subsequent units. In other words, even if a plurality of stretched bodies are formed, the state of pressure stretching in each stretched body is basically the same. Therefore, when a plurality of thermoelectric devices are assembled by using chips appropriately selected from a plurality of chip groups of thermoelectric material cut from each stretched body, the thermoelectric performance of each thermoelectric device tends to be averaged.

In the method according to the first to fourth inventions, the object to be pressurized may be in a heated state or in a normal temperature range. In the heated state, although it differs depending on the composition of the thermoelectric material, etc.,
The temperature of the object to be pressurized is about 100 to 700 ° C, 250 to 6
The temperature can be about 50 ° C. or about 350 to 550 ° C., but is not limited thereto. 4.90 ~
About 98.1 MPa (50 to 1000 kgf / cm ² ), 19.6 to 78.5 MPa (200 to 800 kgf)
/ Cm ² ), 29.4-58.8 MPa (300-
600 kgf / cm ² ), but is not limited thereto. Pressing may be performed in a short time, such as in a forging press, or may be performed over a long time. In order to ensure good press-drawability, pressurization is preferably continued for a long time. As the pressurizing time, the holding time is about 0 to 10 hours, about 40 minutes to 5 hours, and 1 to 4
Time may be appropriately adopted, but is not limited thereto.

[0027] In the method according to the fourth invention, the first pressing and stretching step is performed in a state where the object to be pressed is arranged closer to one side than the center of the first cavity in the first cavity of the first molding container. Then, the object to be pressed is stretched under pressure by the pressure body to form a first stretched body. Thereafter, the first stretched body is arranged in the second cavity of the second molding container in a direction opposite to one of the centers of the second cavities in the second cavity, and in that state, the second pressure stretching step is performed, and the second molding is performed. The first stretched body in the second cavity of the container is stretched under pressure and pressure by a pressure body to form a second stretched body. The stretching direction in the first pressure stretching step;
Since the stretching directions in the pressure stretching step are opposite to each other, variations in the material flow in the second stretched body from side to side are suppressed.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

<Example 1> First, raw materials of bismuth, antimony, and tellurium (purity is 3N, that is, three nines: w
(t9.9%). And Bi
_O.5 Sb _1.5 Te so that the composition of ₃ (numerals molar ratio), and each raw material was weighed and charged raw material into the quartz tube. next,
0.01 wt% silver as an additive to the above raw materials
Add to form a mixture. Thereafter, the inside of the quartz tube was sealed in a vacuum state of 0.133 × 10 ² Pa (0.1 Torr) or less by a vacuum pump. The quartz tube is rocked while being heated at 700 ° C. for 1 hour, and the mixture in the quartz tube is dissolved and stirred. Then, it is solidified and cooled to form an alloy. This alloy is pulverized by a cutter mill, which is a pulverizing means, to obtain an alloy powder, and a thermoelectric material alloy powder having a particle size of 90 μm or less is formed by classification.

FIG. 1 shows a mold apparatus 1. The mold apparatus 1
A cylindrical die 11 having a die hole 10;
1 and a rectangular parallelepiped lower punch 13 fitted to the lower part of the die 11
A box-shaped heating furnace 15 having a heating chamber 14 for accommodating the die 11, the upper punch 12, and the lower punch 13, and a heater disposed so as to coaxially surround the die 11 in the space of the heating chamber 14. 16, a temperature sensor (thermocouple) 17 for detecting a heater temperature, a base 18 for holding the lower punch 13, an upper spacer 19 for fixing the upper punch 12,
Lower spacer 2 that holds base 18 and transmits pressure from a hydraulic cylinder (not shown) located below heating chamber 14
0.

The above-mentioned thermoelectric material alloy powder is applied to a die 11
In a state where a required amount is inserted into the die hole 10, a temperature of 450 ° C. and a pressure of 39.2 MPa (400
(kgf / cm ² ) for 30 minutes. In this way, a lump 2 as a pressing object, which is a thermoelectric material sintered body having a size of 20 mm × 20 mm × 20 mm, is produced. The lump 2 has outer wall surfaces 2a to 2d and has a cubic shape. If it is a cubic shape, the height of the mass 2 which is the object to be pressed can be suppressed, and the buckling deformation of the mass 2 can be suppressed at the time of pressure stretching described below, which is advantageous for performing normal stretching. Become.

FIGS. 2 and 3 show the pressure stretching device 3. The pressure-stretching device 3 is slidably fitted to a thick container 31 formed of a thick cylindrical hard material (metal or ceramic) having a cavity 30 and one end opening (upper end opening) of the forming container 31. A first pressing body 33 having a rectangular cross section and formed of a hard material (metal or ceramic) having a flat first pressing surface 32 and a flat first pressing surface 32, and the other end opening (lower end opening) of the molding container 31. A second pressing member 35 having a rectangular cross section and made of a hard material (metal or ceramic) having a flat second pressing surface 34 fitted slidably.
And

As shown in FIG. 2, the cavity 30 has a substantially rectangular shape which is flat and horizontally long, and is opposed to each other and is a pair of flat first inner wall surfaces 36 (along the vertical direction). 36a, 36b) and a pair of second inner wall surfaces 37 (37) facing each other and extending in the vertical direction.
a, 37b).

In the present embodiment, when being stretched under pressure, the lump 2 is stretched only to the right and left in the direction in which the horizontally long cavity 30 extends, that is, in the arrow X direction. It is not substantially stretched in different directions of arrow Y. That is, stretching along the uniaxial direction is performed.

The mass 2 which is the above-mentioned sintered body of thermoelectric material is
As shown in FIGS. 2 and 3 (showing a state immediately before the pressure stretching), the pressure stretching device 3 is installed at a predetermined installation position in the cavity 30 of the molding container 31. That is, in this embodiment,
When the mass 2 is arranged in the cavity 30, the distance vertically extending from one outer wall surface 2a of the mass 2 to one first inner wall surface 36a of the cavity 30 is defined as a, and the mass facing away from the outer wall surface 2a is defined as a. The distance from the other outer wall surface 2b of the first cavity 30 to the other first inner wall surface 36b of the first cavity 30 is b
(A and b are on the same axis), and when the ratio of a / b is α, a = b and the target value of α is set to 1. a and b
Are located on the same axis.

The larger side of the above a and b is the maximum distance between the outer wall surface of the lump 2 accommodated in the cavity 30 of the molding container 31 and the first inner wall surface 36 of the cavity 30 of the molding container 31. Means distance. The smaller side of the above a and b is the outer wall surface 2a of the lump 2 accommodated in the cavity 30 of the molding container 31 and the cavity 3 of the molding container 31.
0 means the minimum distance connecting the first inner wall surface 36. As described above, in this embodiment, a = b.

As described above, the first pressurizing member 33 is pushed in the direction of the arrow M in a state where the mass 2 is set at the predetermined setting position in the cavity 30 of the molding container 31 of the pressure stretching device 3. To press the lump 2 with the first pressing surface 32. That is, the lump 2 in the cavity 30 of the molding container 31 is stretched under pressure by the first pressing surface 32 of the first pressing member 33 and the second pressing surface 34 of the second pressing member 35, and the hot pressing method is used. A first pressure stretching step is performed. At this time, at a temperature of 450 ° C. and a pressure of 39.2 MPa (400 k
gf / cm ² ). With this, 60mm × 20
A stretched body 5 having a size of mm × 6.7 mm is prepared.
The stretched body 5 has a horizontally long shape, and has a square plate shape in a horizontal cross section. The pressing in the pressing and stretching step is performed continuously for about 30 minutes to 1 hour.

In the above-described pressure stretching step, the lump 2
Is compressed in the height direction and stretched in the horizontal direction (that is, the horizontal direction), in other words, in the direction in which the cavity 30 extends.
In other words, the stretching direction is a direction that intersects with the pressing direction by the first pressing body 33. Thereby, the degree of orientation of the cleavage surface in the stretched body 5 along the two-dimensional direction (that is, the horizontal direction) increases.

In this embodiment, the distance D1 between the second inner wall surfaces 37, which means the width of the cavity 30, and the width of the mass 2 substantially correspond to each other. Therefore, the lump 2 installed in the cavity 30 cannot move or extend in the arrow Y direction, which is a direction intersecting the direction in which the cavity 30 extends (the arrow X direction).

Twelve chip-shaped test pieces were cut out from the stretched body 5 formed by the above-described pressure stretching step. For each test piece, the Seebeck coefficient (μV / K), electrical conductivity (/ Ω · m), and thermal conductivity (W / m · K) were measured. Further, the performance coefficient Z was calculated from the following equation.

Performance coefficient Z = ｛(Seebeck coefficient) ² ×
(Electrical conductivity) // (Thermal conductivity) These results are shown in Table 1 in the column where α is 1.
As shown in Table 1, when α was 1, the standard deviation indicating the variation of the performance coefficient Z according to the present example was small. That is, as shown in Table 1, the standard deviation of the Seebeck coefficient is 0.4 and small, the standard deviation of the electric conductivity is 4.6 and small, and the standard deviation of the performance coefficient Z is 0.01.
It was small. Therefore, if a thermoelectric device is formed by assembling a plurality of chips formed by cutting the stretched body 5 manufactured as described above, the variation in thermoelectric characteristics of the thermoelectric device is suppressed, and the performance of the thermoelectric device is secured well. Is done.

Further, in this embodiment, the agglomerates 2 formed as described above are prepared, and for each agglomerate 2, the ratio of a / b is changed by changing the values of a and b to appropriately change α. In the above-described form, the stretched body is subjected to pressure stretching to form stretched bodies 5. For each test piece with α changed, Seebeck coefficient,
The electric conductivity and the thermal conductivity were measured respectively, and the performance coefficient Z was similarly calculated based on the above equation. This is also Table 1.
Shown in As shown in Table 1, if α is as small as 1.5 or 2 or 2.5 or 3, the standard deviation of the Seebeck coefficient, the standard deviation of the electrical conductivity, and the standard deviation of the figure of merit are all small. Was.

However, as shown in Table 1, when α exceeds 3, the standard deviation indicating the variation increases. It is presumed that the reason is that when α is large, the difference in the flow state between the left and right sides in the pressure stretching direction becomes large, and the degree of orientation varies.

[0044]

[Table 1]

In the first embodiment described above, even when the number of chips to be taken out from the stretched body 5 when configuring a device is large,
All are effective even when the amount is small.

Second Embodiment FIGS. 4 and 5 show a second embodiment. The second embodiment has basically the same configuration as that of the first embodiment. Therefore, a = b and α is defined as 1. The second embodiment has basically the same operation and effect as the first embodiment.
Hereinafter, the different parts will be mainly described.

FIGS. 4 and 5 show a pressure stretching apparatus 3B used in the second embodiment. The pressure-stretching device 3B is fitted into a molding container 31B formed of a thick cylindrical hard material provided with a cavity 30B having a rectangular shape in a plane, and an opening (upper end opening) at one end of the molding container 31B. Flat first pressing surface 3
A first pressing body 33B made of a hard material having 2B;
A second pressing body 35B formed of a hard material having a flat second pressing surface 34B fitted into the other end opening (lower opening) of the molding container 31B.

The cavity 30B has a substantially rectangular shape that is flat and horizontally long, and is a pair of first inner wall surfaces 36B (36B) facing each other and extending in the vertical direction.
a, 36Bb) and a pair of second inner wall surfaces 37B (37Ba, 3B) that are opposed to each other and that are flat along the vertical direction.
7Bb).

A positioning portion 8 having a shallow concave shape is formed in the longitudinal center region of the second pressing surface 34B, which is the upper end surface of the second pressing body 35B. The positioning portion 8 is for fitting the outer wall surface 2d, which is the lower surface of the block 2 before processing and stretching, to position the block 2 at the center of the cavity 30B in the pressing and stretching direction. It is formed in the central region in the drawing direction. The planar shape of the positioning portion 8 is a quadrangle corresponding to the planar shape of the lump 2. The positioning portion 8 has a flat inner wall surface 81 facing the lower end portions of the outer wall surfaces 2a and 2b of the mass 2 before processing and stretching, and a flat outer wall surface 2d as the lower surface of the mass 2 before working and extending. And a bottom surface 82 in a shape of a circle. The depth of the bottom surface 82 is set to be shallow, and when the height of the mass 2 is set to 100 in relative display, it is set to about 1 to 10 in consideration of securing the stretchability and the like. However, it is not limited to this.

Then, as shown in FIG. 5 (showing a state before the pressure drawing), the block 2 of the pressure drawing device 3B was used by using the block 2 which was a thermoelectric sintered body produced in the same procedure as in the first embodiment. By positioning the lump 2 in the positioning portion 8 of the molding container 31B, the lump 2 is housed in the cavity 30B in a state where the lump 2 is placed in the central region in the longitudinal direction of the cavity 30B. Cavity 30
The width size D1 of B and the width size of the block 2 of thermoelectric material substantially correspond. Therefore, the lump 2 is extended right and left in the direction in which the horizontally long cavity 30 extends, that is, in the arrow X direction, but not in the arrow Y direction. That is, stretching along the uniaxial direction is performed.

In this embodiment, as in the first embodiment,
The first pressing body 33B is lowered in the direction of arrow M to press the block 2 on the first pressing surface 32B. Thereby, the first pressing body 33
The lump 2 in the cavity 30B of the molding container 31B is stretched under pressure by the first pressure surface 32B of B and the second pressure surface 34B of the second pressure body 35B, and a pressure stretching step is performed.

In this embodiment, the pressurizing conditions are the same as those in the first embodiment, and the temperature is 450 ° C. and the pressure is 39.2 MPa.
(400 kgf / cm ² ) by a hot press method for a predetermined time. Thereby, the stretched body 5 having the same size (60 mm × 20 mm × 6.7 mm) as in each of the above-described embodiments.
B is manufactured.

In the pressure-stretching step according to this embodiment, the lump 2
As described above, although extending in the direction in which the horizontally long cavity 30B extends, that is, in the direction of the arrow X, the arrow X
It is not stretched in the arrow Y direction different from the direction by 90 degrees.

In the first pressure stretching step, the lump 2
The mass 2 is compressed in the height direction and stretched in the horizontal direction (horizontal direction) to form a stretched body 5B. As a result, the cleaved surface of the stretched body 5 has a two-dimensional direction (horizontal direction).
The degree of orientation increases.

Then, 12 test pieces are cut out from the stretched body 5B formed in the first stretching step. For each test piece, the Seebeck coefficient, the electrical conductivity, and the thermal conductivity were measured, and the performance coefficient Z was similarly calculated.

In this example, the same steps as described above were performed to produce seven stretched bodies 5B. At this time, the mass 2 before the pressure stretching is fitted and set in the concave positioning portion 8 provided in the second pressure body 35B, and the mass 2 is set at the same position in the cavity 30B every time. Similarly, the Seebeck coefficient, the electric conductivity, and the thermal conductivity were measured for these, and the performance coefficient Z was obtained by calculation. Table 2 shows the results.

As shown in Table 2, even when the number of the stretched bodies 5B is increased, the standard deviation of the Seebeck coefficient, the standard deviation of the electric conductivity, and the standard deviation of the figure of merit are small, and the variation of the thermoelectric characteristics is small. It is suppressed. Therefore, if a thermoelectric device is manufactured using the chip taken out from the stretched body 5B,
A thermoelectric device having good thermoelectric properties can be provided. It is presumed that the reason is that the installation position of the block 2 is always the same every time, so that the variation in the orientation of the thermoelectric material in each stretched body 5B is suppressed.

[0058]

[Table 2]

Further, in this embodiment, since the positioning portion 8 is formed, a convex portion 5m which is a target of the concave positioning portion 8 is formed on the stretched body 5B. This is advantageous for determining the orientation relationship of the stretched body 5B. Example 2 described above
Is likely to be particularly effective when a large number of stretched bodies 5B are manufactured, and when a large number of chips are taken out from each stretched body 5B when configuring a device.

Comparative Example 1 Comparative Example 1 has basically the same configuration as Example 2 shown in FIGS. However, the positioning portion 8 is not provided in the cavity 30B. In Comparative Example 1, a molding container 3 of a pressure-stretching apparatus 3B was used by using a lump 2 which was a thermoelectric sintered body produced in the same procedure as in Example 4.
It is housed in the cavity 30B of 1B, and the pressure stretching step is performed under the same conditions as in the second embodiment. In Comparative Example 1, seven stretched bodies 5B are produced by performing the same process. In Comparative Example 1, since the positioning portion 8 was not provided, the set position of the mass 2 before the pressure stretching was not the same every time.
Vary. When the operation is performed manually, the set position of the lump 2 tends to vary considerably.

Similarly, for Comparative Example 1, the Seebeck coefficient, the electric conductivity, and the thermal conductivity were measured, and the performance coefficient Z was calculated. Table 2 shows the results. As shown in Table 2, the standard deviation of the Seebeck coefficient, the standard deviation of the electric conductivity, and the standard deviation of the figure of merit were large, and the dispersion of the thermoelectric characteristics was large.

The reason is that in Comparative Example 1, the lump 2 is set at an arbitrary position in the cavity 30. When the number of lump 2 is large, the lump 2 does not always become a fixed installation position. It is presumed that this is because when the step is performed, the flow and orientation of the material tend to vary in each stretched body.

<Embodiment 3> Embodiment 3 is shown in FIGS. The third embodiment has basically the same configuration as the first embodiment, and has the same operation and effect. However, FIGS. 6 and 7
(State before pressing and stretching) shows a pressing and stretching apparatus 3C used in Example 3. The pressure stretching device 3C is fitted into a molding container 31C made of a thick cylindrical hard material provided with a cavity 30C having a substantially quadrangular planar shape, and one end opening (upper end opening) of the molding container 31C. And the first pressing surface 3 which is flat
A first pressing body 33C made of a hard material having 2C,
A second pressing body 35C made of a hard material having a flat second pressing surface 34C fitted into the other end opening (lower end opening) of the molding container 31C.

As shown in FIG. 6, the cavity 30C of the pressure-stretching apparatus 3C has a substantially quadrangular shape in a plane, and is opposed to each other and substantially flat in a vertical direction. Of the first inner wall surface 36C (36Ca, 36C
b) and a pair of flat second inner wall surfaces 37C (37Ca, 37C) facing each other and substantially along the vertical direction.
Cb).

As shown in FIG. 6, a shallow-bottom concave positioning portion 8C is formed in the center area of the cavity 30C in the directions of the arrows X and Y. The positioning portion 8C is for positioning by fitting the lower portion of the mass 2 and has a square shape in a plane so as to correspond to the planar shape of the mass 2. The positioning portion 8C is provided on the outer end surface 2 of the mass 2 before the processing and stretching.
The inner wall surface 81C where the lower end portions of the a and 2b face, and the bottom surface 82 where the outer wall surface 2d which is the lower surface of the lump 2 before the processing and stretching face.
And C.

Using a block 2 which is a thermoelectric material sintered body formed in the same procedure as in the above-mentioned first embodiment, as shown in FIG. 6, the block 2 is placed in a molding container 31C of a pressure stretching apparatus 3C. The mass 2 is positioned in the positioning portion 8C, and the mass 2 is
Housed in the central area in C. As shown in FIG. 6, when the lump 2 is housed in the cavity 30 </ b> C, a space is formed around the entire outer wall surfaces 2 a to 2 d of the lump 2.

In this embodiment, since the positioning portion 8 is provided in the cavity 30C, the mass 2 is
At the time of installation on C, of the line segments (distance) vertically reaching from the outer wall surface of the block 2 to the first inner wall surface 36C and the second inner wall surface 37C of the cavity 30, the maximum of the line segments located on the same axis The distance is a, the minimum distance is b, and the ratio of a to b (a
Assuming that / b) is α, α can be reliably set to a range not exceeding 3 (generally not exceeding 1.5) every time the mass 2 is placed in the cavity 30C. . In this example, a = b is substantially set, and α = 1.

After the mass 2 is set in the cavity 30C, the mass 2 spreads in the lateral direction (radial direction) as described later by the pressurization in the pressure stretching step. At this time, the lump 2 causes a material flow due to plastic deformation and spreads in the lateral direction, but the maximum distance of the lump 2 in the cavity 30C is the distance c in FIG. On the other hand, the minimum distance of the material flow of the mass 2 in the cavity 30C is:
This is the distance d in FIG. In this example, since the positioning portion 8 is provided in the cavity 30, the ratio between the maximum flow distance c and the minimum flow distance d is β (= c / c).
In the case of d), each time the mass 2 is installed in the cavity 30C, β can be reliably defined in a range not exceeding 3.

Also in this embodiment, as shown in FIG.
In the pressing and stretching step, the first pressing body 33C is lowered in the direction of arrow M to press the mass 2 on the first pressing surface 32C. As a result, the lump 2 in the cavity 30C of the molding container 31C is stretched under pressure by the first pressing surface 32C of the first pressing member 33C and the second pressing surface 34C of the second pressing member 35C. A stretching step is performed. By the first pressure stretching step described above,
The mass 2 is compressed in the height direction and spreads in the lateral direction (radial direction) of the mass 2, that is, in the direction of the arrow 110. Thus, a board-shaped stretched body 5C is produced.

In the pressure-stretching step according to this embodiment, the lump 2
Since is disposed in the central region of the cavity 30C, the lump 2 is radially stretched around the lump as described above. The cleaved surface of the stretched body 5C has a high degree of orientation in the two-dimensional direction (horizontal direction).

From the stretched body 5C formed in the stretching step, 1
Cut out two test pieces. For each of the test pieces, the Seebeck coefficient, the electric conductivity, and the thermal conductivity were measured, and the performance coefficient Z was calculated in the same manner. Standard deviation of Seebeck coefficient,
Standard deviation of electrical conductivity and standard deviation of figure of merit are large,
The variation in thermoelectric characteristics was small.

Further, in Embodiment 3 shown in FIGS. 6 and 7, α is appropriately changed within a range where α does not exceed 3.
The position of the positioning part 8C was changed. When α changes, β also changes. In the state where α was changed as described above, a pressure stretching step was performed to form a stretched body 5C. Then, as described above, the Seebeck coefficient, the electric conductivity, and the thermal conductivity were measured, and the performance coefficient Z was similarly calculated. The standard deviation of the Seebeck coefficient, the standard deviation of the electrical conductivity, and the standard deviation of the figure of merit were small, and the dispersion of the thermoelectric properties was small.

As in the first embodiment, when α and β exceed 3, the standard deviation of the Seebeck coefficient, the standard deviation of the electric conductivity, and the standard deviation of the figure of merit become large. Specifically, when α and β exceed 3, the difference in the flow state between the left and right in the stretching direction of the lump 2 during the pressure stretching becomes large.
, The dispersion of the performance is large inside.

<Embodiment 4> Embodiment 4 is shown in FIGS. Embodiment 4 has basically the same configuration as Embodiment 3.
It has the same effect. 8 and 9 show a pressure stretching device 3D used in the fourth embodiment. The pressure stretching device 3D includes a molded container 31D formed of a thick cylindrical hard material having a flat circular cavity 30D, and a molded container 31D.
Is fitted into one end opening (upper end opening) of the
First pressing body 3 made of a hard material having a pressing surface 32D
3D and a second pressing body 35D formed of a hard material having a flat second pressing surface 34D fitted into the other end opening (lower end opening) of the molding container 31D.

In the central area of the second pressing surface 34D of the second pressing body 35D, there is formed a positioning portion 8D for fitting and positioning the lower part of the block 2. The positioning portion 8D is provided in a central area of the cavity 30. The positioning unit 8D
It has an inner wall surface 81D facing the lower end portions of the outer wall surfaces 2a and 2b of the lump 2 before processing and stretching, and a bottom surface 82D facing an outer wall surface 2d that is the lower surface of the lump 2 before processing and stretching. As shown in FIG. 8, the cavity 30D of the molding container 31D of the pressure stretching device 3D has a circular shape in a plane, and has an inner wall surface 36D extending in a ring shape.

Using a block 2 which is a thermoelectric material sintered body formed in the same procedure as in the above-described embodiment 1, as shown in FIG. 9, the block 2 is placed in a forming container 31D of a pressure stretching apparatus 3D. The block 2 is positioned in the positioning section 8 and the lump 2 is accommodated in the central area in the circular cavity 30D. Therefore, a space is formed around the mass 2 in the lateral direction.

Since the positioning portion 8 is provided in the cavity 30D, also in the present embodiment, when the mass 2 is installed in the cavity 30D, the ring shape of the cavity 30D is vertically set from the outer wall surface of the mass 2. When the maximum distance is a, the minimum distance is b, and the ratio of a / b is α on the same axis of the distance (line segment) reaching the inner wall surface 36D, every time the block 2 is installed In each case, α can be reliably defined in a range not exceeding 3 (generally not exceeding 1.5). In FIG. 8, a is substantially set to a = b, and α is set to 1.

After the mass 2 is set in the cavity 30D, the mass 2 spreads in the lateral direction (radial direction) as described later by the pressurization in the pressure stretching step. At this time, the mass 2 causes a material flow along with the plastic deformation and spreads in the lateral direction. The maximum distance of the material flow of the mass 2 in the cavity 30D is the distance c in FIG. On the other hand, the minimum distance of the material flow of the mass 2 in the cavity 30D is:
This is the distance d in FIG. And in this example, since the positioning part 8D is provided in the cavity 30D,
The ratio between the maximum flow distance c and the minimum flow distance d is β (= c
/ D), β can be reliably defined in a range not exceeding 3 every time the mass 2 is placed in the cavity 30D.

In this example, too, in the pressure stretching step,
The first pressing body 33D is lowered in the direction of arrow M to
The block 2 is pressed by the pressing surface 32D. This allows the first pressurization
The first pressing surface 32D of the body 33D and the second pressing body 32D of the second pressing body 35D
Inside the cavity 30D of the molding container 31D with the pressing surface 34D
Is stretched under pressure, and the first pressure stretching step is performed.
You. In Example 4, at a temperature of 450 ° C. and a pressure of 39.2 MP
a (400 kgf / cm ^Two) By hot press method
It is stretched by applying pressure for a fixed time. The first pressure stretching process described above
Depending on the process, the mass 2 is compressed in the height direction and
Direction). This makes a disk-shaped stretched body 5D.
To make.

In the pressure-stretching step according to the fourth embodiment,
Since is disposed in the central region of the cavity 30D, the lump 2 is extended around the periphery in the radial direction, that is, along the direction of the arrow 112. The cleavage surface in the stretched body 5D is 2
The degree of orientation in the dimensional direction (horizontal direction) increases.

The stretched body 5D formed in the stretching step
Two test pieces were cut out. For each of the test pieces, the Seebeck coefficient, the electric conductivity, and the thermal conductivity were measured, and the performance coefficient Z was calculated in the same manner. The standard deviation of the Seebeck coefficient, the standard deviation of the electric conductivity, and the standard deviation of the figure of merit were large, and the dispersion of the thermoelectric characteristics was small.

Further, the position of the positioning portion 8D is changed so that α is appropriately changed in a range where α and β do not exceed 3, and the pressure stretching process is performed in each of the changed positions.
Form D. Then, as described above, the Seebeck coefficient, the electric conductivity, and the thermal conductivity were measured, and the performance coefficient Z was similarly calculated. The standard deviation of the Seebeck coefficient, the standard deviation of the electrical conductivity, and the standard deviation of the figure of merit were small, and the dispersion of the thermoelectric properties was small.

When α exceeds 3, the standard deviation of the Seebeck coefficient, the standard deviation of the electric conductivity, and the standard deviation of the figure of merit become large. Specifically, when α and β exceed 3, the difference in the flow state between the left and right sides of the stretched body 5D during the pressure stretching becomes large, and the dispersion of the performance inside the stretched body 5D becomes large.

<Fifth Embodiment> FIG. 10 shows a fifth embodiment. The fifth embodiment has basically the same configuration as the fourth embodiment shown in FIGS. 8 and 9, and basically has the same operation and effect. However, the lump 2H has a disk shape, not a cubic shape, and has a circular shape in a plane. Therefore, the positioning unit 8H
Is formed with a shallow circular concave portion corresponding to the planar shape of the lump 2H, and is located in the central region of the cavity 30D. The outer wall 2k of the mass 2H is the cavity 3
It is arranged concentrically with the ring-shaped inner wall surface 36D of 0D.

Also in this embodiment, the lump 2H is set in the cavity 30D with the lump 2H positioned at the positioning portion 8H. At this time, in a line segment vertically extending from the outer wall surface k of the block 2 to the ring-shaped inner wall surface 36D of the cavity 30D, the maximum distance is a and the minimum distance is b on the same axis.
When the ratio of a / b is α, it is possible to set a = b every time the block 2 is installed, and α is reliably set to 1
(That is, within 3). Since the lump 2H is thus arranged in the central region of the cavity 30D, the lump 2H is radially stretched around the lump 2H in the pressure stretching step.

<Embodiment 6> Embodiment 6 is shown in FIGS. The sixth embodiment has basically the same configuration as the first embodiment, and has the same operation and effect. Hereinafter, the different parts will be mainly described. In Example 6, both the first pressure stretching step and the second pressure stretching step are performed. In this embodiment, in the first pressure stretching step, the pressure stretching device 3 shown in FIGS. 11 and 12 is used.
F is used as a first pressure stretching device. The press-drawing and stretching apparatus 3F includes a first molding container 3 made of a thick, tubular, hard material having a first rectangular cavity 30F.
1F, a first pressurizing body 33F fitted with one end opening (upper end opening) of the first forming container 31F and formed of a hard material having a flat first pressing surface 32F;
And a second pressing member 35F formed of a hard material having a flat second pressing surface 34F fitted to the other end opening (lower end opening) of F.

The first cavity 30F has a flat and horizontally long rectangular shape, and is a pair of first inner wall surfaces 36F (36Fa, 36Fa) facing each other and extending along the vertical direction.
36Fb) and a pair of flat second inner wall surfaces 37F (37Fa, 37F) facing each other and extending in the vertical direction.
b).

In the first disposing step, a lump 2 (size: 20 mm × 20 mm × 20 mm), which is a sintered body of thermoelectric material, manufactured by the same procedure as in the first embodiment is used. Then, as shown in FIG. 12, the mass 2 is accommodated in the first cavity 30F of the pressure stretching device 3F. At this time, the lump 2 is arranged to be close to one side in the first cavity 30F such that one outer wall surface 2b of the lump 2 contacts the first inner wall surface 36Fb (36F) of the first cavity 30F. In this case, in the first arrangement step, one outer wall surface 2b of the mass 2
Is positioned so as to contact the first inner wall surface 36Fb of the first cavity 30F, so that the first inner wall surface 36Fb of the first cavity 30F positions the mass 2 in the direction in which the first cavity 30F extends. Can function as

The width D1 of the first cavity 30F
And the width size of the mass 2 substantially corresponds. Therefore, when the mass 2 is pressurized, the first cavity 30 having the horizontally long shape is formed.
The film is stretched only in the direction in which F extends, that is, in the direction of arrow X2, and is not substantially stretched in the direction of arrow Y2 that is different from arrow X2 by 90 degrees. That is, stretching along the uniaxial direction is performed.

The first pressing body 33F is lowered in the direction of arrow M to press the mass 2 on the first pressing surface 32F, and the first pressing body 33F is pressed.
The mass 2 is pressure-stretched by the first pressure surface 32F of F and the second pressure surface 34F of the second pressure member 35F, and a first pressure-stretching step is performed. Pressurization was continued for about 30 minutes to 1 hour. By the above-described first pressure stretching step, the lump 2 is compressed in the height direction and spreads in the horizontal direction (horizontal direction = arrow X2 direction), and the first stretched body 5 (size: 40 mm × 20 mm × 10 mm)
Is formed. The thickness of the first stretched body 5F is about half the thickness of the mass 2 before the pressure stretching, and the length of the first stretched body 5F is about twice the length of the mass 2 before the pressure stretch. It is. First
The stretched body 5F has a quadrangular shape in cross section, and has outer wall surfaces 5r and 5s facing each other.

After performing the first pressure stretching step, the second pressure stretching step is performed on the first stretched body 5F. Therefore, in this embodiment, in addition to the pressure stretching device 3F, the pressure stretching device 3H shown in FIGS. 13 and 14 is used as the second pressure stretching device. The pressure stretching device 3H includes a second molding container 31H formed of a thick cylindrical hard material having a second rectangular cavity 30H that is horizontally long and flat, and a second molding container 3H.
A first pressing body 33H formed of a hard material having a flat first pressing surface 32H and fitted into one end opening (upper opening) of 1H, and the other end opening (lower opening) of the second forming container 31H. And a second pressing body 35H formed of a hard material having a flat second pressing surface 34H.

The second cavities 30H have a flat and horizontally long rectangular shape so as to be longer than the first cavities 30F in the extending direction. The second cavities 30H face each other and are substantially flat along the vertical direction. A pair of first inner wall surfaces 3
6H (36Ha, 36Hb) and a pair of second inner wall surfaces 37H (37Ha, 37Hb) facing each other and substantially flat along the vertical direction.

The first stretched body 5F described above is used in FIGS.
As shown in (2), it is housed in the second cavity 30H of the second pressure stretching device 3H. In this case, the first stretched body 5F is placed in the second cavity 30H with respect to the case of the first pressure stretching step.
In the opposite direction. That is, the outer wall surface 5r on the left side in the drawing of the first stretched body 5F is
H is brought into contact with the first inner wall surface 36Ha (36). As described above, in the second arrangement step, the outer wall surface 5r on the left side in the drawing of the first stretched body 5F is connected to the first inner wall surface 36Ha of the second cavity 30H.
, The first inner wall surface 36Ha
Is the mass 2 in the direction in which the first cavity 30F extends.
Can function as a positioning unit for positioning the.

With the first stretched body 5F disposed in the second cavity 30H as described above, the first pressing body 33H is lowered in the direction of arrow M2, and the first stretched body 5F is lowered at the first pressing surface 32H. Apply pressure. Thereby, the first pressure body 33H
The first stretched body 5F is stretched in the direction of the arrow X3 by the pressurizing surface 32H and the second pressurizing surface 34H of the second pressurizing body 35H.
A pressure stretching step is performed to form a second stretched body 5H.

That is, in the second pressure stretching step, the first stretched body 5F is further compressed in the thickness direction and spreads in the horizontal direction (horizontal direction), and the second stretched body 5H (size: 60 mm × 2
0 mm x 6.7 mm). The thickness of the second stretched body 5H is 6.7 mm, and the first stretched body 5F before the pressure stretching is performed.
And the length of the second stretched body 5H was 60 mm, which was about 3/2 times the length 40 mm of the first stretched body 5F before the pressure stretching. The cleavage plane in the second stretched body 5H is highly oriented in the two-dimensional direction (horizontal direction).

Twelve test pieces were cut out from the second stretched body 5H formed by sequentially performing both the first pressure stretching step and the second pressure stretching step. The Seebeck coefficient, electric conductivity, and thermal conductivity of each test piece were measured, and the coefficient of performance Z was similarly calculated. As shown in Table 3, the standard deviation of the Seebeck coefficient, the standard deviation of the electrical conductivity, and the standard deviation of the figure of merit were small. It is presumed that the reason is that the difference between the left and right flow states in the pressure stretching direction is suppressed, and the variation in the degree of left and right orientation in the stretching direction is suppressed.

[0097]

[Table 3]

In the above-described embodiment, the first pressure stretching step and the second pressure stretching step are sequentially performed. However, the present invention is not limited to this. After the first pressure stretching step and the second pressure stretching step are sequentially performed, the third pressure stretching step and the fourth pressure stretching step may be sequentially performed. In order to equalize the orientation, the stretching direction in the third pressure stretching step and the stretching direction in the fourth pressure stretching step are reversed.

(Application Example) A plurality of chips are cut from a stretched body formed based on the above-described pressure stretching method, and each chip is assembled to produce a thermoelectric device shown in FIG.
The thermoelectric device is mounted between the substrates 80 and 82 by being soldered to the pair of substrates 80 and 82 having electrical insulating properties facing each other, the electrode layer 85 formed on the substrates 80 and 82, and the electrode layer 85. And a plurality of chips 87 provided. Each chip 87 is electrically connected in series.
When the power is supplied, one of the substrates 80 and 82 is cooled by the thermoelectric action, and the other of the substrates 80 and 82 is heated.

(Supplementary Note) The following description can be understood from the above embodiment. -A method for pressure-stretching a thermoelectric material having both the configuration of claim 1 or 2 (α or β does not exceed 3) and the configuration of claim 2 (positioning portion). The constitution of claim 1 or 2 (α or β does not exceed 3) and claim 3 (the stretching direction in the first pressure stretching step and the stretching direction in the second pressure stretching step are opposite to each other) And a pressure stretching method for a thermoelectric material. -Combination of the configuration of claim 2 (positioning portion) and the configuration of claim 3 (the stretching direction in the first pressure stretching step and the stretching direction in the second pressure stretching step are opposite to each other) Pressure stretching method for thermoelectric materials. A step of preparing a pressurized object formed of a thermoelectric material capable of exhibiting thermoelectric properties and a molding container having a cavity for accommodating the pressurized object; And a pressure-stretching step of pressing the object to be pressurized in the cavity of the molding container with a pressurizing body and press-stretching the object to be pressed by plastic working to form a stretched body In the thermoelectric material pressurizing and stretching method, which is performed sequentially. A gap is provided on both sides of the object to be pressed in a direction parallel to the two straight lines, and the length of the line segment in one of the gaps provided on both sides of the object to be pressed is A1, and the other is A1. The straight line in the gap on one side of When the length was A2, A1 ≧ A
2. The method of drawing and drawing a thermoconductive material under pressure, wherein (A1 / A2) <3. In the embodiment described above, A1 is displayed as a and A2 is displayed as b.

[0101]

According to the method for stretching a thermoelectric material under pressure according to the first aspect of the present invention, in the disposing step, from the outer wall surface of the object to be pressed housed in the cavity of the molding container to the inner wall surface of the molding container vertically. When the maximum distance / minimum distance among the distances reached is α, α is set so as not to exceed 3. According to the method according to the first aspect of the invention, it is possible to prevent the flow phenomenon during the pressure stretching from being excessively biased by each part of the cavity. That is, the difference in the flow state in each part of the cavity is suppressed. Therefore, the standard deviation of the Seebeck coefficient, the standard deviation of the electric conductivity, and the standard deviation of the figure of merit can both be reduced, which is advantageous for providing a thermoelectric device with stable performance.

According to the thermoelectric material pressing and stretching method according to the second invention, in the arranging step, the maximum flow of the material flowing distance when the object to be pressed is plastically deformed by the plastic working in the pressing and stretching step. The ratio β of the distance c to the minimum flow distance b (= c /
The object to be pressurized is arranged in the cavity so that d) does not exceed 3. According to the method according to the second aspect of the invention, it is possible to prevent the flow phenomenon during the pressure stretching from being excessively biased by each part of the cavity. That is, the difference in the flow state in each part of the cavity is suppressed. Therefore, the standard deviation of the Seebeck coefficient, the standard deviation of the electric conductivity, and the standard deviation of the figure of merit can both be reduced, which is advantageous for providing a thermoelectric device with stable performance.

According to the thermoelectric material pressurizing and stretching method of the third invention, the molding container has a positioning portion for positioning the pressurized object at a set position in the cavity.
The object to be pressed is positioned in the positioning portion of the molding container and is arranged in the cavity. According to the method according to the third aspect of the present invention, even when a large number of lumps are stretched under pressure, the pressurized object formed of the thermoelectric material can be surely located at a specific position in the cavity every time before the stretching. Is positioned. For this reason, even when a large number of stretched bodies are manufactured, variations in the orientation between a plurality of stretched bodies that have been stretched under pressure are suppressed. Thereby, the average property value of the stretched body stretched under the first pressure, the average property value of the stretched body stretched under the second pressure, and the average property value of the stretched body stretched under the third pressure are obtained. Variations between them are reduced.
The same applies to the fourth and subsequent times. Therefore, the standard deviation of the Seebeck coefficient, the standard deviation of the electric conductivity, and the standard deviation of the figure of merit can both be reduced, which is advantageous for providing a thermoelectric device with stable performance.

According to the thermoelectric material pressurizing and stretching method according to the fourth aspect of the present invention, the object to be pressurized is arranged closer to one side of the first cavity of the first molding container than the center of the first cavity. The first pressure stretching step is performed to form a first stretched body. After that, the first stretched body is arranged in the second cavity of the second molding container in a direction opposite to the center of the second cavity in the second cavity, and in this state, the second pressure stretching step is performed to perform the second stretching.
Form a stretched body. Since the stretching direction in the first pressure stretching step and the stretching direction in the second pressure stretching step are opposite to each other, variations in the material flow in the second stretched body from side to side are suppressed. Therefore, the left-right variation of the orientation in the second stretched body is suppressed. Therefore, the standard deviation of the Seebeck coefficient, the standard deviation of the electric conductivity, and the standard deviation of the figure of merit can both be reduced, which is advantageous for providing a thermoelectric device with stable performance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold apparatus for forming a lump according to a first embodiment.

FIG. 2 is a plan view of a forming container of the pressure stretching device according to the first embodiment.

FIG. 3 is a cross-sectional view of a pressure stretching device immediately before pressure stretching according to Example 1.

FIG. 4 is a plan view of a molding container of the pressure stretching device according to the second embodiment.

FIG. 5 is a cross-sectional view of a pressure stretching device immediately before pressure stretching according to Example 2.

FIG. 6 is a plan view of a forming container of the pressure stretching device according to the third embodiment.

FIG. 7 is a cross-sectional view of a pressure stretching device immediately before pressure stretching according to Example 3.

FIG. 8 is a plan view of a molding container of the pressure stretching device according to the fourth embodiment.

FIG. 9 is a cross-sectional view of a pressure stretching device immediately before pressure stretching according to Example 4.

FIG. 10 is a plan view of a forming container of the pressure stretching device according to the fifth embodiment.

FIG. 11 is a plan view of a first forming container of the pressure stretching device according to the sixth embodiment.

FIG. 12 is a cross-sectional view of a first pressure stretching device immediately before pressure stretching according to Example 6.

FIG. 13 is a plan view of a second forming container of another pressure stretching apparatus according to the sixth embodiment.

FIG. 14 is a cross-sectional view of a second pressure stretching device immediately before pressure stretching according to Example 6.

FIG. 15 is a cross-sectional view schematically showing a thermoelectric device on which a chip taken out from a stretched body is mounted according to an application example.

[Explanation of symbols]

In the figure, 2 is a lump, 2a to 2d are outer wall surfaces, 30 is a cavity, 31 is a molding container, 33 is a first pressing body, 35 is a second pressing body, 5 is a stretched body, and 8 is a positioning part. Shown respectively.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirotane Sugiura 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Inventor Hiroyasu Kojima 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Inside the corporation

Claims (5)

[Claims] 1. A step of preparing a pressurized object formed of a thermoelectric material capable of exhibiting thermoelectric properties and a molding container having a cavity for accommodating the pressurized object; An arranging step of arranging the object in the cavity of the container, and pressurizing the object to be pressurized in the cavity of the molding container by a pressurizing body, and pressurizing and stretching the object to be pressed by plastic working to form a stretched body. And a pressure-stretching method for sequentially performing a pressure-stretching step, wherein, in the arranging step, the inner wall surface of the molding container is perpendicular to an outer wall surface of the object to be pressed housed in a cavity of the molding container. The maximum distance a and the minimum distance b are defined so that the ratio α (= a / b) of the maximum distance a and the minimum distance b of the line segments located on the same axis among the line segments reaching the same axis does not exceed 3. So that the pressurized object can be Pressure rolling Shin method of the thermoelectric material, characterized in that arranged in the I. 2. A step of preparing a pressurized object formed of a thermoelectric material capable of exhibiting thermoelectric properties, and a molding container having a cavity for accommodating the pressurized object; An arranging step of arranging the object in the cavity of the container, and pressurizing the object to be pressurized in the cavity of the molding container by a pressurizing body, and pressurizing and stretching the object to be pressed by plastic working to form a stretched body. In the pressure stretching method of the thermoelectric material to perform the pressure stretching step in order, in the arrangement step, of the material flow distance when the object to be pressed is plastically deformed by plastic working in the pressure stretching step, The ratio β of the maximum flow distance c to the minimum flow distance b (=
A method for pressure-drawing a thermoelectric material, wherein the object to be pressed is arranged in the cavity such that c / d) does not exceed 3. 3. The molding container according to claim 1, wherein the molding container has a positioning portion for positioning the object to be pressed at a set position in the cavity. A method for pressure-stretching a thermoelectric material, wherein the object to be pressed is positioned in the cavity while being positioned, and α or β is set so as not to exceed 3. 4. A step of preparing a pressurized object formed of a thermoelectric material capable of exhibiting thermoelectric properties, and a molding container having a cavity for accommodating the pressurized object; An arranging step of arranging the object in the cavity of the container, and pressurizing the object to be pressurized in the cavity of the molding container with a pressurizing body, and pressing and stretching the object to be pressed by plastic working to form a stretched body. And a pressure-stretching method for sequentially performing a pressure-stretching step, wherein the forming container has a positioning portion for positioning the object to be pressed at a set position in the cavity. The method for pressurizing and stretching thermoelectric material, wherein the pressurizing object is positioned in the cavity while the pressurizing object is positioned on the positioning portion. 5. A first molding container having a thermoelectric material capable of exhibiting thermoelectric properties, a first molding container having a first cavity for accommodating the pressing object, and a first cavity of the first molding container. Preparing a second molding container having a second cavity extending more in the stretching direction than the first molding container, wherein the object to be pressurized is located within the first cavity of the first molding container more than the center of the first cavity. A first disposing step of disposing the pressure object on one side, and pressurizing the object to be pressurized in a first cavity of the first molding container by a pressurizing body, and pressing and stretching the object to be pressurized by plastic working. A first pressure stretching step of forming a first stretched body, and disposing the first stretched body in the second cavity of the second molding container in a direction opposite to the one of the second cavity center from the center of the second cavity. A second disposing step; and a second key of the second molding container. Pressurizing the first stretched body in the cavity with a pressurized body and pressurizing and stretching the first stretched body by plastic working to form a second stretched body. Pressure stretching method of thermoelectric material.