JP2003095783A - Manufacturing apparatus and method for bulk of oxide eutectoid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems with bulk of an oxide eutectoid which is usable for gas turbine blades for thermal power generator, the grain refining of which does not proceed because of a gentle temperature gradient (2 to 3 deg.C/mm) in a growth direction in a conventional method, or a Bridgman method, and has unsufficient strength. SOLUTION: The bulk of the oxide eutectoid is manufactured by an apparatus providing the bottom of an iridium metal or an iridium alloy crucible with a plurality of narrow pores, bringing the melt flowing down from these narrow pores into contact with the plane at the top end of the seed crystal to join the flows thereof, drawing out the joined melt downward by a seed crystal holder and solidifying and growing the melt unidirectionally. The homogeneous grain refining of the eutectic tissue is made successful by realizing the temperature gradient as steep as 150 deg.C/mm in maximum in the crystal growth direction and simultaneously realizing the homogeneous temperature distribution with respect to a radial direction. The practicable properties within the scope of 1,500 deg.C and 800 MPa in the atmosphere exceeding (about 5 times) conventional strength is obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an oxide eutectic (Al ₂ O ₃ / YAG, Al ₂ O ₃ / YAG / ZrO ₂ etc.) suitable for a heat resistant structural material.
The present invention relates to a bulk manufacturing apparatus and manufacturing method.

[0002]

2. Description of the Related Art Oxide eutectic has received attention as a high temperature structural material. Conventionally, the Bridgman method is exclusively used for the production of this material.

[0003]

Currently, turbine blades and furnace walls in a gas turbine system for thermal power generation are
Since there is no structural material that can withstand temperatures above 1300 ° C, cooling operation is performed although efficiency is reduced. If 1500 ° C uncooled operation in the atmosphere becomes possible, it is estimated that energy efficiency will improve by about 10%, and a 1% improvement will lead to energy savings on the scale of 1 trillion yen. Therefore, the social effect of developing a heat-resistant structural material that enables uncooled operation is great. In addition, the material is used for engine parts of automobiles and furnace walls of incinerators in oxidizing atmospheres.
Applications in the 200 ° C range are also expected.

Up to now, the oxide eutectic has been expected as a candidate material for the above-mentioned application fields, but in the conventional Bridgman method, the temperature gradient in the growth direction (2 to 3 ° C.) is used. / Mm), the size of the eutectic structure, which holds the key to the strength, becomes large, and the eutectic structure does not become finer, and the strength sufficient for practical use is 1500 ° C and 1000 MPa in the atmosphere. However, only a material that exhibits a strength of about 300 MPa at 1500 ° C. can be obtained,
The improvement in strength was stalled.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have developed a method and apparatus for realizing a steep temperature gradient in the growth direction that cannot be reached by the Bridgman method and at the same time realizing a gentle temperature gradient in the radial direction. As a result, the eutectic structure became finer and succeeded in obtaining a bulk of an oxide eutectic body which brought about a dramatic improvement in strength.

That is, the present invention comprises a crucible, a seed crystal holder for holding a seed crystal to be brought into contact with the melt flowing out from the pores provided at the bottom of the crucible, and a moving mechanism for moving the seed crystal holder downward. A unidirectional solidification growth apparatus comprising a moving speed control device of the moving mechanism and an induction heating means for heating the crucible, wherein the crucible is an iridium metal or an iridium alloy crucible, and an iridium metal or an iridium metal is formed on the outer periphery of the bottom of the crucible. An after-heater, which is a heating element made of an iridium alloy, is arranged, and the crucible and the after-heater allow the amount of heat generation to be adjusted by adjusting the output of the induction heating means, so that the melt liquid drawn out from the pores provided in the bottom of the crucible can be adjusted. in a possible and the device controlling the heating temperature of the solid-liquid boundary phase, provided a plurality of pores crucible bottom, the effective segregation coefficient k _eff shown the diameter of the pores in equation 1 below Becomes _{1, k eff = k [k} + (1-k) exp (-Vd / D)] -1 ( Equation 1) and the size Satoshi melt does not drip, and the upper end of the seed crystal and a horizontal plane, An apparatus for manufacturing a bulk of an oxide-based eutectic body, characterized in that a plurality of pores are arranged at an interval such that a melt flowing down from a plurality of pores can be brought into contact with the upper end plane of a seed crystal and merged. .

Further, according to the present invention, by using the above-mentioned apparatus, an oxide raw material powder having a eutectic composition is inserted into a crucible and melted, and the powder is downwardly moved by a seed crystal holder from a plurality of pores provided at the bottom of the crucible. At the start of the extraction of the eutectic body that is pulled out and unidirectionally solidifies and grows, first, the upper end plane of the seed crystal is brought into contact with the melt flowing down from the central pore of the plurality of pores, and the melt is spread horizontally. Contact the melt flowing down from the adjacent pores,
A method for producing an oxide eutectic bulk, which comprises observing a formed meniscus and confirming that a target crystal diameter is obtained, and then performing crystal growth at a predetermined rate.

In the present invention, the above apparatus is used to insert the oxide raw material powder having a eutectic composition into the crucible and melt the powder, and the seed crystal holder is used to move downward through a plurality of pores provided at the bottom of the crucible. A method for producing an oxide eutectic bulk, characterized in that the eutectic that is pulled out and undergoes unidirectional solidification growth is set at a rate of 0.01 to 20 mm / min. Further, the present invention is the above-mentioned method for producing an oxide-based eutectic bulk, wherein the temperature gradient in the growth direction is 0 to 150 ° C./mm.

The present inventors previously arranged an after-heater on the outer periphery of the bottom of the iridium metal or iridium alloy crucible, and made it possible to adjust the heat generation amount of the after-heater, so that the micro-pulled down from the pores provided at the bottom of the crucible. By making it possible to control the heating temperature of the solid-liquid boundary phase of the melt drawn by using the apparatus, the width of the eutectic lamella can be set to 10
A method for producing an oxide-based eutectic ceramic fiber having a fine isotropic structure of μ or less and a thickness of several hundred to several tens of μm and excellent in high-temperature strength characteristics has been developed (JP-A-11-278994).

According to the above method, a eutectic fiber having a eutectic structure size which is one-tenth that of the Bridgman method can be produced by using the method of sharply lowering the temperature gradient. However, if the small hole provided at the bottom of the crucible is enlarged, the phenomenon of "melt melts down" occurs, and bulk crystal growth cannot be performed by the pull-down method.
There was a big problem to make it.

In the present invention, by improving this method, the temperature gradient in the crystal growth direction is 2 to 3 of the Bridgman method.
Eutectic by a crystal production technology that realizes a steep temperature gradient of up to 150 ° C / mm, preferably 100 to 150 ° C / mm with respect to ° C / mm, and at the same time realizes an extremely uniform temperature distribution in the radial direction. We succeeded in making the structure homogeneously fine, and obtained a result that the practically applicable materiality was within the range of 1500 MPa and 800 MPa in the air, which was significantly (about 5 times) higher than the conventional strength.

In the method of indirectly heating by setting the resistance heating furnace around the crucible, not only the crucible but also the peripheral part is heated, so that it is suitable for realizing a gentle temperature gradient in the growth direction, but it is steep. No temperature gradient can be realized. The present invention uses an iridium metal or iridium alloy crucible as the crucible and uses the high frequency induction heating means to heat only the crucible and heat and melt the raw material without heating the surrounding atmosphere, so that a steep temperature gradient can be realized. .

Further, the eutectic structure is extremely sensitive to the temperature distribution, and if the temperature distribution in the radial direction has a gradient, the eutectic structure becomes non-uniform. In the present invention, the crucible is an iridium metal or iridium alloy crucible, the melt flowing down from a plurality of pores in the bottom of the crucible is united to form a meniscus to form a bulk eutectic crystal. It will be.

The method of the present invention has a standard growth rate of 15 m.
It can be set to a high speed of m / min and a maximum of 20 mm / min, and the crystal growth speed is 400 to 1200 times faster than that of the Bridgman method.

According to the present invention, high strength can be realized even in bulk, which greatly contributes to the practical application of an oxide eutectic having excellent characteristics. Since the oxide eutectic obtained by the method of the present invention does not show grain growth even in a high temperature oxidizing atmosphere of 1500 ° C. and exhibits high oxidation resistance, it is a heat resistant structural material such as a member of a jet engine or an ultra high temperature gas turbine. Can be expected to be put into practical use. In addition, it can be used as an engine member of an automobile (exhaust gas system, valve drive, etc.) or as an incinerator wall.

Further, the manufacturing method of the present invention is a manufacturing method which can manufacture not only a cylindrical shape but also a square shape or a plate shape depending on the arrangement of the pores. It is expected to be possible and the yield will be high.

[0017]

DETAILED DESCRIPTION OF THE INVENTION The apparatus of the present invention will be described with reference to FIG. The circle in the left part of FIG. 1 shows an enlarged view of the bottom of the crucible 1. The raw material is held in the crucible 1. Since the raw material for producing the oxide eutectic is a high melting point substance, high frequency induction heating is used, and the crucible is preferably made of a high melting point material such as iridium metal or iridium-rhodium alloy containing 1 to 20% of rhodium.

Iridium has poor wettability with the oxide eutectic melt (contact angle is 90 ° <θ), and forms a stable meniscus between the melt flowing down from the crucible pores and the seed crystal. Therefore, it is preferable. Also, when using such a crucible,
Since the melt causes convection in the crucible, the obtained eutectic has high homogeneity.

The crucible 1 is held by an alumina holder 3, the alumina heat insulating material 4 is used to shield the entire crucible 1, and the crucible 1 is installed in a quartz tube 5. On the outer circumference of the quartz tube 5, R for high frequency induction heating
The F coil 6 is arranged and the raw material in the crucible 1 is heated and heated to be melted to form a melt. An after-heater 2 which is a heating element made of iridium metal or iridium alloy is installed on the side surface of the bottom of the crucible 1.

In order to prevent the oxidation of the crucible, an atmosphere of Ar gas is used, and an atmosphere gas such as an inert gas whose ratio to O ₂ used for improving the crystallinity is strictly controlled is introduced from the upper part of the quartz tube 5. , Exhaust from the bottom. As shown in an enlarged view, a plurality of pores 7 through which the oxide eutectic melt flows down are provided in the lower part of the crucible 1.

The melt flows downward through a plurality of vertical pores 7 provided at the bottom of the crucible 1 and flows downward.
By contacting the seed crystal (sapphire) 9 set to, and pulling down the pull-down axis of the seed crystal holder 8, unidirectional solidification growth is performed to form the bulk 10 of the eutectic body, and the seed crystal holder 8 is moved downward by the moving mechanism. It is continuously lowered. As a moving mechanism of the seed crystal holder 8, a known means such as a mechanism for rotating the seed crystal holder 8 by a ball screw, a servo motor and a gear to move it can be adopted.

FIG. 2 is a schematic view showing a mode of a step of bringing the melt into contact with the seed crystal and pulling it down from the pores at the bottom of the crucible. First, as shown in the drawing, the seed crystal 9 having a diameter smaller than the diameter of the eutectic bulk to be produced and smaller than the pore diameter is used as the center of the pores 7.
-3 (A in FIG. 2), and a meniscus as shown in FIG. 3 to be described later is formed at the center of the bottom of the crucible. The diameter of the seed crystal 9 is smaller than the width between the pores adjacent to the pore 7-3.

When the seed crystal 9 is slowly moved downward in this state, that is, when crystal growth is started, the melt flowing down from the pores 7-3 begins to spread horizontally and the adjacent pores 7-
When reaching 2 and 7-4, a wider meniscus is formed by helping the supply of the melt flowing down from the pores (Fig. 2).
B). Similarly, crystal growth is slowly continued until the melt spreads over the entire bottom of the crucible (C in FIG. 2). After confirming with the CCD camera that the melt has spread over the entire bottom of the crucible and the target crystal diameter has been obtained, crystal growth is performed at a required speed (for example, 20 mm / min) (D in FIG. 2).

Since fine pores are prepared at the time of producing a small-diameter fiber, special measures for parameters such as pore diameter and depth are not important, but when making a bulk body. Are parameters that cannot be ignored.

The effective segregation coefficient k _eff that defines the pores is expressed by the following equation 1. k _eff = k [k + (1-k) exp (-Vd / D)] ^-1 (Equation 1) where D is the diffusion coefficient in the liquid phase, and k = C _A ^S / C _A ^L (C _A ^S : concentration of the mixed phase in the solid phase, C _A ^L : concentration of the mixed phase in the liquid phase), d is the thickness of the diffusion phase, and V is the growth rate. Setting the effective segregation coefficient k _eff shown in Expression 1 to 1 is essential for making the produced crystal homogeneous.

[0026] The depth of the pores corresponds to the diffusion phase thickness d.
Therefore, the pore diameter has a strong correlation with D (as the diameter increases, D
Have to grow). As can be seen from Equation 1, effective segregation
Coefficient k_{ef f}To set 1 to 1, increase V and d and decrease D.
Ideally.

In the pull-down method, the crystal growth rate V is much faster than in the conventional method, and this is ideal. It is desirable that the depth of the pores is large corresponding to the diffusion phase thickness d.
That is, the deeper the pores, the better. However, if it is too deep, the work of seed touch becomes very difficult,
The optimum value needs to be matched to the target object. For example, in the case of an oxide eutectic, the depth is preferably 2 mm or more and 5 mm or less. Further, the diameter of the pore has a strong correlation with D (the larger the diameter, the larger D).

In order to increase the crystal diameter R _cry , the crucible pores
The R _cap must be increased, but if this is done, the melt will drip from the small holes, so the effective pore segregation coefficient R _{eff of the} crucible pore R _cap will be approximately 1 and the diameter at which the melt will not drip. As a result, a plurality of pores were provided at the lower end of the crucible, and the melt flowing down from the plurality of pores was brought into contact with the upper end plane of the seed crystal to join them. In the case of an oxide eutectic, the diameter at which the melt does not drip is 400 μmφ or less, preferably 2
It is 00 μmφ to 300 μmφ. The depth of the pores is 2 mm to 5 mm from the viewpoint of controlling the segregation coefficient k _eff and the viscosity of the melt.
A degree is preferable.

In the present invention, the melt flowing down from the pores at the bottom of the crucible is Rcap of the pores of the crucible and R of the crystal shown in FIG.
A meniscus is formed in the melt portion, which is defined by the height between cryst and the lower end of the crucible and the crystal. The outside of the curve indicated by the circle and the dotted line in the figure is the stable growth region, and the inside of the curve is unstable. However, in the present invention, since Rcap cannot be increased, the bottom surface R _bottom of the crucible was used as a parameter for diameter control instead. As a result, the pulling speed is 20 mm / mi
Stable growth was certainly possible up to a high speed of n.

When bulk unidirectional solidification growth of an oxide-based eutectic is carried out using the apparatus of the present invention, the crucible pore R _cap is made of a kind of oxide-based eutectic material so as to satisfy the above requirements. Determined according to. Further, the number of pores is determined so as to satisfy the above condition according to the size of the eutectic material. First, as shown in FIG. 2A, a seed crystal (sapphire) 9 having a flat tip is formed.
Is located below the central pore 7-3 of the crucible 1 and is brought into contact with the melt that has melted the raw material and is accumulated in the pore 7-3, and the melt spreads in the horizontal direction from the adjacent pores. The melt flowing out from a plurality of pores is brought into contact with the flowing melt and merges to start unidirectional solidification growth to form a solid-liquid interface.

The amount of heat generated by the after-heater 2 is controlled by the power of the RF coil 6 according to the variation of the solidified portion formed between the melt and the seed crystal flowing down from the tips of the plurality of pores 7 at the bottom of the crucible 1. Adjust by increasing or decreasing. Therefore, the plurality of pores 7
A CCD camera viewing window 12 is provided in the alumina heat insulating material 4, and an opening is provided in the alumina holder 3 and the after-heater 2 so that the melt at the tip of the can be observed from the outside of the quartz tube 5.

By observing the melt width and height with a CCD camera, the relational expression between the number of pixels counted according to the melt width and height and the power adjustment of the induction heating coil 6 is obtained in advance, and the actual reduction is performed. In step 2, the heat generation temperature of the after-heater 2 is adjusted by increasing or decreasing the power of the high frequency induction heating coil 6 based on the variation of the pixel count number obtained by the CCD camera.

By adjusting the heat generation temperature of the after-heater 2, the unidirectional solidification growth rate of the eutectic is macro-controlled.
That is, when the height of the melt at the tips of the plurality of pores 7 is large, the temperature is lowered, and when the height is small, the temperature is raised, and macroscopic control of the solidification growth rate of the eutectic can be performed. Further, the microscopic control of the crystallinity is performed by finely adjusting the pulling speed by speed control of a moving mechanism (not shown) based on the observation of the diameter of the bulk 10 of the eutectic.

The Al ₂ O ₃ --Y ₂ O ₃ eutectic is an Al ₂ O ₃ -3Y ₂ containing about 18 to 22 mol% Y ₂ O _3.
O ₃ · 5Al ₂ O ₃ a (YAG) as the beginning, about 39 to
43 mol%, about 58-62 mol%, about 78-82 mol%
A eutectic composition containing Y ₂ O ₃ in each range is also suitable. Other Al ₂ O ₃ / YAG / ZrO ₂ , Al ₂ O ₃ / RAP
(R: rare earth, P: perovskite) eutectic, Al ₂ O ₃
/ RAG, Fe ₃ O ₄ / RIP (I: iron), Fe ₃ O ₄ / R
IG, ZrO ₂ / RZP, ZrO ₂ / RZG and other 2
It is also possible to apply to a ternary oxide eutectic.

[0035]

[Example] Example 1 The raw material is Y₂ O₃ , Al₂ O₃ (Both are 99.99%)
Oxide powder is Al₂O ₃ Several g in eutectic composition of / YAG
What was charged and well stirred was used. Crucible and after
-Iridium metal is used for the heater and it is made of ceramic
The heat of the induction heating coil is 5.00
The melting point was set to kW or less, and melting was performed at a melting temperature of 1840 ° C. Oxygen
1mm in diameter with flat top in an argon gas flow atmosphere containing
Sapphire single crystal rod as a seed crystal
Therefore, the setting lowering speed is set to 20 mm / min.
Directionally solidified and grown.

Iridium metal crucible pore size is 200 μm
φ, and the distance between them was 3 mm, and seven pieces were provided. The depth of the pores was 4 mm.

The after heater had a cylindrical shape, and the distance from the outer surface of the eutectic bulk to the inner surface of the cylinder was 4 mm. An Al ₂ O ₃ / YAG eutectic rod with a diameter of 7 mm having the appearance shown in FIG. 4 was obtained. The structure of the obtained bulk eutectic is refined to 1 μm or less, and the size is uniform even when the outside of the bulk and the vicinity of the center are compared. When the eutectic structure is inhomogeneous, it causes strength deterioration, but in the eutectic body manufactured by the manufacturing method of the present invention, as shown in FIG.
(B) A uniform fine structure was obtained in the central part. This is because the Ir crucible itself holding the melt is heated by the high frequency, and a uniform temperature distribution is realized in the radial direction.

Example 2 The raw material of Example 1 was charged with ZrO ₂ (99.99%) oxide powder so as to have an eutectic composition of Al ₂ O ₃ / YAG / ZrO ₂ , and the same procedure as in Example 1 was performed. A eutectic rod was produced. Al ₂ O ₃ / YA with a diameter of 7 mm shown in FIG.
A G / ZrO ₂ eutectic bulk was obtained.

Example 3 An oxide eutectic plate-like bulk was produced under the same conditions as in Example 2, using an iridium metal crucible having fine pores arranged linearly at the bottom of the cylindrical container shown in FIG. As shown in FIG. 7, the external shape is Al ₂ O ₃ / YAG having a width of 7 to 10 mm and a thickness of 1 mm.
A / ZrO ₂ eutectic plate-like bulk was obtained.

[0040]

INDUSTRIAL APPLICABILITY The unidirectionally solidified eutectic bulk of the present invention is extremely excellent in high temperature tensile strength and is particularly suitable as a heat resistant structural material used in a high temperature oxidizing atmosphere. Further, the apparatus of the present invention uses an iridium crucible having a plurality of pores having a short length at the bottom as a crucible, and realizes temperature control of the melt portion of the crucible bottom by using an afterheater, which is simple. Due to the device structure, the long-awaited excellent effect of mass-producing the oxide eutectic bulk can be brought about.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a manufacturing apparatus of the present invention.

FIG. 2 is a schematic diagram showing an aspect of a step of bringing a melt into contact with a seed crystal and pulling it down from pores at the bottom of the crucible in the production method of the present invention.

FIG. 3 is a schematic view showing a state of a meniscus of a melt in the manufacturing method of the present invention.

FIG. 4 is a drawing-substitute optical photograph showing a shape of an oxide eutectic bulk obtained in Example 1 and Example 2.

5 is a drawing-substitute microstructure photograph showing a microstructure of an oxide eutectic bulk obtained in Example 1. FIG.

FIG. 6 is a schematic diagram of a crucible bottom for obtaining a plate-shaped oxide eutectic bulk of Example 3.

7 is a drawing-substitute optical photograph showing the shape of the plate-shaped oxide eutectic bulk obtained in Example 3. FIG.

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[Procedure amendment]

[Submission date] November 16, 2001 (2001.11.
16)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

Up to now, the oxide eutectic has been expected as a candidate material for the above-mentioned application fields , but in the Bridgman method, which is a conventional method, a gradual temperature gradient in the growth direction (2 to 3 ° C. / mm), the size of the eutectic structure, which holds the key to the strength, becomes large, the eutectic structure does not become finer, and the strength sufficient for practical use is 1500 ° C and 1000 MPa in the atmosphere. However, 1500 ℃
However, only a material exhibiting a strength of about 300 MPa was obtained, and improvement in strength was stalled.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

Means for Solving the Problems The present inventor develops a method and apparatus for realizing a steep temperature gradient in the growth direction, which cannot be achieved by the Bridgman method, and at the same time, realizing a uniform temperature distribution in the radial direction. As a result, the eutectic structure became finer and succeeded in obtaining a bulk of an oxide eutectic body which brought about a dramatic improvement in strength.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

FIG. 2 is a schematic view showing a mode of a step of bringing the melt into contact with the seed crystal and pulling it down from the pores at the bottom of the crucible. First, as shown in the figure, a seed crystal 9 having a diameter smaller than that of the eutectic bulk to be produced and larger than the pore diameter is brought into contact with the central pore 7-3 (A in FIG. 2), and the seed crystal 9 is attached to the central portion of the crucible bottom. A meniscus as shown in FIG. 3 described later is formed. The diameter of the seed crystal 9 is smaller than the width between the pores adjacent to the pore 7-3.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

The depth of the pores corresponds to the diffusion phase thickness d, and the diameter of the pores has a strong correlation with D (the larger the diameter, the larger D). As can be seen from Equation 1, to 1 the effective segregation coefficient k _{e ff} is, V, to reduce the D by increasing the d is ideal.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

By observing the melt width and height with a CCD camera, the relational expression between the number of pixels counted according to the melt width and height and the power adjustment of the induction heating coil 6 is obtained in advance, and the actual reduction is performed. In step 2, the power of the high frequency induction heating coil 6 is increased or decreased to adjust the heat generation temperatures of the crucible and the after-heater 2 based on the variation of the pixel count number obtained by the CCD camera.

Claims (4)

[Claims] 1. A crucible, a seed crystal holder for holding a seed crystal to be brought into contact with a melt flowing out from a fine hole provided at the bottom of the crucible, a moving mechanism for moving the seed crystal holder downward, and the moving mechanism. A unidirectional solidification growth apparatus equipped with a moving speed control device and an induction heating means for heating the crucible, wherein the crucible is an iridium metal or iridium alloy crucible and is made of iridium metal or iridium alloy on the outer periphery of the crucible bottom. An after-heater, which is a heating element, is arranged.The crucible and the after-heater are capable of adjusting the amount of heat generation by adjusting the output of the induction heating means, and the solid-liquid boundary phase of the melt drawn out from the pores provided at the bottom of the crucible. In the apparatus capable of controlling the heating temperature of No. 1, a plurality of pores are provided at the bottom of the crucible, and the diameter of the pores is the effective segregation coefficient k shown in the following formula 1.
_eff becomes 1 and k _eff = k [k + (1-k) exp (-Vd / D)] ^-1 (Equation 1) and the size is such that the melt does not drip, and the upper end of the seed crystal is a horizontal plane. And an apparatus for manufacturing a bulk oxide-based eutectic body, characterized in that a plurality of pores are arranged at intervals such that the melt flowing down from the plurality of pores can be brought into contact with the upper end plane of the seed crystal and merged. . 2. Using the apparatus according to claim 1, an oxide raw material powder having a eutectic composition is inserted into a crucible and melted, and then pulled down by a seed crystal holder from a plurality of pores provided at the bottom of the crucible. At the start of drawing out the eutectic body that undergoes unidirectional solidification growth, the upper end plane of the seed crystal is first brought into contact with the melt flowing down from the central pore of the plurality of pores, and the melt is spread horizontally and adjacent The eutectic oxide-based eutectic characterized by performing crystal growth at a predetermined rate after confirming that the meniscus formed by contacting with the melt flowing down from the pores to obtain the desired crystal size Bulk manufacturing method. 3. The apparatus according to claim 1, wherein an oxide raw material powder having a eutectic composition is inserted into a crucible and melted, and the powder is drawn downward by a seed crystal holder from a plurality of pores provided at the bottom of the crucible. The pull-out speed of the eutectic crystal that undergoes unidirectional solidification growth is 0.
01-20 mm / min, The manufacturing method of the oxide type eutectic body bulk characterized by the above-mentioned. 4. A temperature gradient in the growth direction of 0 to 150 ° C./m
The method for producing an oxide-based eutectic bulk according to claim 3, wherein m is m.