JP2005297556A - Molding method of uniaxial orientation molding and its molding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding method of a uniaxial orientation molding formed of substance particles having crystal magnetic anisotropy, in which any two of magnetic susceptibilities are equal and these magnetic susceptibilities are greater than the other one magnetic susceptibility, or formed of a substance having fiber axis magnetic anisotropy, in which any two of magnetic susceptibilities are equal and these magnetic susceptibilities are greater than the other one magnetic susceptibility, and also provide its molding device. <P>SOLUTION: To form the molding by a slip casting method, a porous mold 24 having slurry 23 therein is placed on a stand 22, the stand 22 is rotated at low speed so as not to cause a flow in the slurry, and a magnetic field is applied by making superconductive current flow to a superconductive coil 21. To form a molding of an organic substance oriented in a fiber axis direction from a suspension formed of an organic substance such as collagen, fibrin or the like, the mold 24 having the suspension 23 formed of the organic substance is placed on the stand 22, the stand 22 is heated and rotated, and the magnetic field is applied by making the superconductive current flow to the superconductive coil 21 so as to gelate the suspension. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for molding a molded article having excellent crystal orientation or fiber axis orientation from substance particles having crystalline magnetic anisotropy or fibrous substance having magnetic anisotropy, and molding the molded article. It is related with the apparatus to do.

A molded body produced by molding a powder of crystal particles into a desired shape, or a molded body produced by further firing this molded body can realize a shape according to the application at low cost. It is widely used as an element, biomaterial, filter material, reinforcing material, medical material, or optical material.
By the way, since the crystalline substance has thermal, optical, chemical, electromagnetic, physicochemical, or mechanical properties specific to the crystal plane or specific to the crystal axis direction, If the crystal orientation can be added to the film, the characteristic properties can be maximized.

  Further, if a fibrous organic substance can be oriented in the fiber axis direction to form a molded body, it is extremely useful as a biomaterial. That is, when cells are cultured on collagen or fibrin oriented in the fiber axis direction, a cell tissue oriented in the fiber axis direction is obtained, and this cell tissue is known to be similar to a biological tissue. Therefore, if a fiber axis oriented molded body having the shape of bone, tooth or cartilage made of collagen or fibrin is formed and cell culture is performed on this molded body, artificial bone, tooth or cartilage with extremely good biocompatibility can be obtained. Can be used.

Conventionally, (1) extrusion molding method, (2) slip casting method, (3) slip-casting method in magnetic field, etc. are known as crystal orientation methods for powder of crystal particles.
The extrusion molding method of (1) utilizes the fact that when the liquid flows between narrow slits, the powder of crystal particles suspended in the fluid is aligned in the direction with less fluid resistance due to its shape anisotropy. It is. In the slip casting method of (2), when there is a primary relationship between the shape of the substance and the crystal direction, the crystal orientation is performed using the fact that the powder of crystal particles dropped in the fluid takes the same deposition posture depending on the shape. It is. In the slip casting method in the magnetic field (3), a magnetic field is applied during slip casting, and the difference in magnetization energy accompanying crystal magnetic anisotropy of the powder of crystal particles, that is, the dependence of the magnetic susceptibility on the crystal axis is determined. This is a method in which crystal orientation is performed.
In addition, as a method for orienting fibrous organic materials, anisotropy of the magnetic susceptibility of organic materials can be achieved by applying a magnetic field while producing crystallized organic materials dissolved in a solvent or chemical reaction. A method of aligning by using is known.

  The material is either a ferromagnetic material, a diamagnetic material, or a paramagnetic material, and today, a strong magnetic field can be obtained at a low cost by a superconducting coil. This is useful in that it can be applied to an extremely large number of substances.

By the way, in the method of orienting by a magnetic field, when the crystal particle powder is a single crystal particle and has different magnetic susceptibility in the triaxial direction of the crystal, that is, having crystal magnetic anisotropy. In such a case, it is known that the crystal orientation is such that the direction of the crystal axis having the highest magnetic susceptibility is aligned with the direction of the applied magnetic field. However, the powder of crystal particles obtained by ordinary means is often a powder having no magnetic anisotropy because a plurality of single crystal particles are easily bonded in a random crystal orientation, For this reason, it has been difficult to apply this method to a very large number of substances. The present inventors made such a powder of crystal particles into a powder having a magnetic anisotropy equivalent to the crystal magnetic anisotropy of a single crystal particle by applying a peptizer and a shearing force, By slip casting using this powder under a strong magnetic field by a superconducting coil, we succeeded in uniaxial orientation of materials with low magnetic susceptibility, such as diamagnetic materials and paramagnetic materials, which were previously impossible. (See Patent Document 1).
Japanese Patent Application No. 2003-349352

However, even if a powder having magnetic anisotropy equivalent to single crystal particles is obtained, uniaxial orientation may not be achieved. That is, when the magnetic susceptibility of any one of the crystal a, b, c axis directions, χ _a , χ _b , χ _c is the largest, the uniaxial orientation with the axial direction aligned with the magnetic field direction. A molded body can be molded, but if any two magnetic susceptibilities are equal and these magnetic susceptibilities are larger than the other magnetic susceptibility, the crystal axes corresponding to the two magnetic susceptibilities are in the direction of the magnetic field. Therefore, there is a problem that a uniaxially oriented molded body cannot be molded. Many of such substances exist in hexagonal substances.
Note that the equivalent magnetic susceptibility means that when applying a magnetic field to form a uniaxially oriented molded body by a slip casting method or the like, the difference is small even if the magnetic susceptibility is different from each other. This means the magnetic susceptibility when crystal axes oriented in the direction of the magnetic field are mixed due to the influence of particle flow and thermal motion, that is, when uniaxial orientation cannot be substantially achieved.
In addition, the crystallized body of collagen, which is an organic substance, has a magnetic anisotropy that any two magnetic susceptibilities are equal, and these magnetic susceptibility is larger than the other one magnetic susceptibility, The conventional technique cannot obtain a collagen molded body uniaxially oriented in the fiber axis direction.

  In view of the above-mentioned problems, the present invention is a substance having crystal magnetic anisotropy in which any two magnetic susceptibilities are equal and the magnetic susceptibility is higher than the other magnetic susceptibility, or any two magnetizations It is a first object of the present invention to provide a method capable of forming a uniaxially oriented molded body of a fibrous material having the same rate and having a magnetic anisotropy greater than the other one. To do. A second object is to provide an apparatus capable of molding these uniaxially oriented molded bodies.

In order to achieve the first object, a method for molding a uniaxially oriented molded body of the present invention is a crystalline magnetic anisotropy in which any two magnetic susceptibilities are equal and the magnetic susceptibility is larger than the other one. It is characterized in that when a molding made of the above-mentioned substance is molded by slip casting, a slurry of material particles having properties is placed in a porous mold and is molded while applying a rotating magnetic field.
Another structure of the molding method of the uniaxially oriented molded body of the present invention is a substance in which any two magnetic susceptibilities are equal and the magnetic susceptibility is greater than the other one magnetic susceptibility. The particle suspension is held in a mold container, and the solvent component of the suspension is evaporated to form a molded body made of the above-mentioned substance, and is molded while applying a rotating magnetic field.
According to these methods, a uniaxially oriented molded body composed of material particles having crystal magnetic anisotropy in which any two magnetic susceptibilities are equal and the magnetic susceptibility is larger than the other one is obtained. Can be obtained.

The other configuration of the molding method of the uniaxially oriented molded body of the present invention is a fibrous shape in which any two magnetic susceptibilities are equal and these magnetic susceptibility is larger than the other one magnetic susceptibility. When a molded body made of the above substance is molded by holding a suspension made of the above substance in a mold container and evaporating the solvent component of the suspension, it is molded while applying a rotating magnetic field.
Still another structure of the molding method of the uniaxially oriented molded body of the present invention is a fiber in which any two magnetic susceptibilities are equivalent and these magnetic susceptibility is larger than the other one magnetic susceptibility. When a molded body made of the above material is molded by slip casting, a suspension made of a material is put into a porous mold and molded while applying a rotating magnetic field.
According to these methods, a uniaxially oriented molded body made of a fibrous material in which any two magnetic susceptibilities are equal and these magnetic susceptibilities are larger in magnetic anisotropy than the other one. Can be obtained.

Another structure of the molding method of the uniaxially oriented molded body of the present invention is that an organic substance having any two magnetic susceptibilities and having a magnetic susceptibility higher than the other magnetic susceptibility is crystallized by a chemical reaction. When molding a molded body made of the above-mentioned substance, the molded body made of the above-mentioned substance is molded while applying a rotating magnetic field.
According to this method, it is possible to obtain a uniaxially oriented molded body made of an organic material in which any two magnetic susceptibilities are equal and the magnetic susceptibility is larger than the other one.

The slurry of material particles having crystal magnetic anisotropy is preferably a slurry prepared by applying a shearing force while adding a peptizer. If this slurry is used, even a powder made of a material that is difficult to obtain magnetic anisotropy has a magnetic anisotropy equivalent to that of single crystal particles, so that a uniaxially oriented molded body can be obtained. .
In addition, it is preferable to add a seed crystal that promotes crystal growth of the material to be molded into the slurry or suspension, and then to perform sintering. According to this method, crystals grow from a uniaxially oriented molded body, so that uniaxial orientation is further enhanced.

The rotating magnetic field is preferably applied by rotating a porous mold or mold container in the same plane in a uniform magnetic field.
The porous mold or the mold container may be fixed, and the direction of the applied magnetic field may be rotated in a plane.
According to this method, a rotating magnetic field can be applied to a porous mold or a substance in a mold container.

  The rotating magnetic field is preferably a rotating magnetic field of 2 Tesla or more generated by a superconducting coil. In this case, a uniaxially oriented molded body can be molded even if the material is a material having a low magnetic susceptibility such as a paramagnetic material or a diamagnetic material.

A molding apparatus for a uniaxially oriented molded body of the present invention includes a coil arranged so that a magnetic field direction is horizontal, and a mounting table that is mounted in the coil and rotates in a horizontal plane with a porous mold or a mold container mounted thereon. It is characterized by having.
According to this apparatus, since a rotating magnetic field can be applied, any two magnetic susceptibilities are equivalent, and these magnetic susceptibility is uniaxially formed of a material having a crystalline magnetic anisotropy larger than the other one magnetic susceptibility. An oriented molded body can be produced.

The coil is preferably a superconducting coil. In this case, a uniaxially oriented molded body can be molded even if the material is a material having a low magnetic susceptibility such as a paramagnetic material or a diamagnetic material that requires a rotating magnetic field of 2 Tesla or more.
The mounting table preferably has a heating device. In this case, the solvent component of the suspension can be easily evaporated by heating the mounting table with a heating device.

  According to the method and apparatus of the present invention, a material having a magnetocrystalline anisotropy, the magnetic anisotropy of which any two magnetic susceptibilities are equal and these magnetic susceptibility is larger than the other one magnetic susceptibility. A uniaxially oriented molded body can be molded even if it is a fibrous material or an organic material. Further, even if the substance is a ferromagnetic material, a paramagnetic material, or a diamagnetic material, a uniaxially oriented molded product can be molded.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, in the case of a substance in which any two magnetic susceptibilities are equal and these magnetic susceptibility is larger than the other one magnetic susceptibility, the conventional fixed magnetic field application method, The reason why a uniaxially oriented molded body cannot be obtained will be described.
FIG. 1 is a diagram showing the definition of a surface in the slip casting method by applying a fixed magnetic field. In the figure, reference numeral 1 denotes a molded body molded by the slip casting method. In this figure, the molded body 1 is a rectangular parallelepiped. A solid line arrow 2 indicates the direction of the applied magnetic field, and a dotted line arrow 3 indicates the direction of gravity. Of the surfaces of the molded body 1, the surface perpendicular to the gravity direction 3 is the upper surface 4, and among the side surfaces parallel to the gravity direction 3, the front surface 5 is the front surface in the drawing, and the side surface perpendicular to the upper surface 4 and the side surface 5 is the surface. Let it be side surface 6.
1A shows an arrangement relationship between the applied magnetic field direction and the surface of the molded body 1 when the applied magnetic field direction is perpendicular to the gravitational direction, and FIG. 1B shows the applied magnetic field direction. The arrangement | positioning relationship between the applied magnetic field direction and the surface of the molded object 1 in the case of being parallel to the direction of gravity is shown.

FIG. 2 is a diagram showing the orientation state when the particles having crystal magnetic anisotropy are molded by the slip casting method by applying a fixed magnetic field, with the orientation planes appearing on each surface of the molded body. The difference of the orientation state by the magnitude relationship of the magnetic susceptibility in the axial direction is shown.
As shown in FIG. 2A, it is assumed that the particles having magnetocrystalline anisotropy are orthorhombic crystal particles, and the magnetic susceptibility in the a, b, and c axis directions is χ _a , χ _b , χ, respectively. _c . In FIG. 2A, the crystal grain of (I) has a magnetic susceptibility χ _{c in the} c-axis direction larger than the magnetic susceptibility χ _a , χ _{b in} the other biaxial directions, that is, χ _c > χ _a , Let χ _b . The crystal grains of (II) have a magnetic susceptibility χ _{c in the} c-axis direction smaller than the other biaxial susceptibility χ _a and χ _b , and χ _a and χ _b are substantially equal, that is, χ _c <Χ _a ≈χ _b .

FIG. 2B is a diagram showing crystal planes appearing on each surface of the molded body shown in FIG. 1 with respect to the two applied magnetic field directions shown in FIG. In the figure, a, b, and c represent orthorhombic a-plane, b-plane, and c-plane, respectively. In the case of a fibrous material, the plane orthogonal to the fiber axis corresponds to the c-plane, and the parallel plane corresponds to the a-plane or b-plane.
As shown in FIG. 2B, in the case of the crystal particle (I), the crystal particle is oriented so that the c-axis direction having the largest magnetic susceptibility χ _c coincides with the applied magnetic field direction. When 2 is perpendicular to the gravitational direction 3, only the c plane appears on the side surface 6 orthogonal to the magnetic field direction 2, and the a and b surfaces appear on the upper surface 4 and the side surface 5 in a mixed manner. When the magnetic field application direction 2 is parallel to the gravity direction 3, only the c surface appears on the upper surface 4 orthogonal to the magnetic field direction 2, and the a surface and the b surface are mixed on the side surface 5 and the side surface 6. appear. That is, in this case, a molded body oriented in the c-axis direction, that is, a uniaxially oriented molded body is obtained.
On the other hand, in the case of the crystal particle (II), there are two directions of the a-axis and the b-axis having the largest magnetic susceptibility, so when the magnetic field application direction 2 is perpendicular to the gravity direction 3, The a-plane and the b-plane appear together on the side surface 6 orthogonal to the magnetic field direction 2, and the a-plane, b-plane, and c-plane appear together on the upper surface 4 and the side surface 5. When the magnetic field application direction 2 is parallel to the gravity direction 3, the upper surface 4 orthogonal to the magnetic field direction 2 appears in a mixed manner with the a surface and the b surface, and the side surface 5 and the side surface 6 have The a-plane, b-plane and c-plane appear together. That is, in this case, there is no surface of the molded body composed of a single crystal plane, and a uniaxially oriented molded body cannot be obtained.

  In the case of the crystal particle of (II) shown in FIG. 2 (a), the present invention can be uniaxially oriented by applying a rotating magnetic field, that is, any two magnetic susceptibilities are equivalent. In addition, even a substance having a crystal magnetic anisotropy having a magnetic susceptibility higher than that of the other magnetic susceptibility can be uniaxially oriented.

Next, by applying a rotating magnetic field, even if the magnetic susceptibility of any two of them is the same and these magnetic susceptibility is larger than the other one, it is uniaxial. The reason why the oriented molded body can be molded will be described.
Since the magnetization is magnetic polarization, when the applied magnetic field direction and the magnetization direction do not match, a rotational force that tries to match the magnetization direction and the magnetic field direction is applied to the crystal particles. This rotational force is a rotational force around an axis perpendicular to the plane defined by the magnetic field direction and the magnetization direction, and is decomposed into a rotational force around a crystal 3 axis having a direction depending on the spatial arrangement of crystal grains. be able to. Crystal grains move according to the equation of motion determined from the rotational force (that is, torque) in the three-axis direction of the crystal and the moment of inertia around each crystal axis. Move to be uniaxially oriented.

The principle of uniaxial orientation of crystal grains will be described below.
FIG. 3 is a diagram for explaining the principle of the method of the present invention. FIG. 3A shows the shape of the crystal particle 10 used in the method of the present invention. Since most of materials having magnetocrystalline anisotropy have shape anisotropy, for the sake of brevity, the crystal particles 10 are long in the c-axis direction as shown in FIG. Are orthorhombic single crystals, and the magnetic susceptibility is χ _c <χ _b <χ _a .
The direction of the rotating magnetic field changes continuously, but for the sake of simplicity, the effect of the rotating magnetic field will be described assuming that the rotating magnetic field H rotates discontinuously from the X-axis direction to the Y-axis direction.

FIG. 3B shows that when the magnetic field H is applied in the X-axis direction, the crystal particles 10 are arranged with the a-axis direction having the highest magnetic susceptibility aligned with the magnetic field H direction (that is, in an a-axis orientation state). In addition, the crystal particle 10 whose c-axis is inclined by an angle β from the Z-axis in the ZY plane perpendicular to the magnetic field H is shown. Also, let M be the magnetization in the a-axis direction.
Considering the case where the magnetic field H rotates in the Y-axis direction, a rotational force acts on the magnetization M, and this rotational force can be divided into rotational forces in the crystal 3-axis direction. If the angle β is 0 °, of course, only the rotational force around the c-axis exists, and it rotates around the c-axis. If the angle β is 90 °, there is only a rotational force around the b-axis, and it rotates around the b-axis. If the angle β is between 0 ° and 90 °, the rotational force exists around the c-axis and the b-axis, respectively, and rotates around the c-axis and the b-axis. By the way, if the moments of inertia around the c-axis and the b-axis are the same and the angle β is smaller than 45 °, the rotational force around the c-axis is larger than the rotational force around the b-axis. Around the b axis, and then around the b axis. Furthermore, when the crystal grain 10 is long in the c-axis direction, the moment of inertia with the c-axis as the rotation axis is the smallest compared to the moment of inertia with the a-axis and b-axis as the rotation axis. The phenomenon of rotating around the b axis and then rotating around the b axis is more likely to occur. Let β ₀ be the spatial arrangement condition of the crystal grains 10 where this phenomenon occurs, that is, the limit angle.

FIG. 3C shows a state in which the angle β is less than β ₀ , so that it has been rotated 90 ° around the c-axis first. In this state, since the direction perpendicular to the plane defined by the magnetic field H and the magnetization M coincides with the b-axis, there is no longer any rotational force around the c-axis, and only the rotational force around the b-axis remains. It is the state that was done. Due to the rotational force around the b-axis, the crystal grains 10 rotate around the b-axis in a direction that decreases the angle β, that is, in a direction that aligns the c-axis with the Z-axis direction. FIG. 3D shows a state where the c-axis is aligned in the Z-axis direction.
In this state, even if the magnetic field H rotates, the axis perpendicular to the plane defined by the directions of the magnetization M and the magnetic field H coincides with the c axis, and only the rotational force around the c axis is present. Even if it rotates, it only rotates around the c-axis, and the c-axis of the crystal grain 10 is fixed in the Z direction.

On the other hand, crystal grains having an inclination angle β larger than β ₀ rotate around the b-axis at the same time, or rotate around the b-axis first. Does not occur. However, when crystal grains having an inclination angle β smaller than β ₀ are Z-axis oriented as described above, a gap is generated between the crystal grains. When a gap occurs between crystal grains, a crystal grain having an inclination angle β larger than β ₀ rotates to fill the gap, and the inclination angle β becomes smaller than β _0. To come. By repeating this cycle, all crystal grains are Z-axis oriented.
In the above description, for the sake of brevity, χ _b <χ _{a has} been described. However, when χ _b ≠ χ _a , the axial direction first arranged in the magnetic field H direction is the a-axis direction or b It is clear that the Z-axis orientation of the c-axis is caused by a similar mechanism, except that it is in the axial direction.
In this way, by applying a rotating magnetic field, even if the magnetic particle has a magnetic susceptibility of χ _c <χ _b ≈χ _a , a molded body that is uniaxially oriented in the direction perpendicular to the magnetic field rotation plane can be obtained. Can be obtained.

Next, the shaping | molding apparatus using the rotating magnetic field of this invention is demonstrated.
FIG. 4 is a schematic cross-sectional view showing the configuration of a molding apparatus using a rotating magnetic field according to the present invention. In the figure, a molding apparatus 20 using a rotating magnetic field has a superconducting coil 21 having a magnetic field direction in a horizontal plane, and a mounting table 22 arranged in the superconducting coil 21 and capable of rotating in the horizontal plane. . The mounting table 22 may have a heating device that can be heated to a desired temperature.
When the molded body is molded by the slip casting method with this apparatus 20, the porous mold 24 containing the slurry 23 is placed on the mounting table 22, and the mounting table 22 is slow enough not to cause flow in the slurry. While rotating at a speed, a superconducting current is passed through the superconducting coil 21 to apply a magnetic field.
An organic material molded body in which any two magnetic susceptibilities, such as collagen, are oriented in the fiber axis direction from a turbid liquid of a fibrous organic material having a magnetic susceptibility higher than that of the other one. In order to mold, instead of the slurry 23, the organic material turbid liquid 23 is placed in the mold container 24, the container 24 is placed on the mounting table 22 and rotated, and the superconducting coil is heated while evaporating the solvent. A superconducting current is passed through 21 to apply a magnetic field. Alternatively, a fibrous substance having magnetic anisotropy is crystallized by a chemical reaction, and a superconducting current is passed through the superconducting coil 21 while rotating the mounting table 22 to apply a magnetic field.

  According to the above apparatus, even if any two of the magnetic susceptibilities are equal and the magnetic susceptibility is larger than that of the other magnetic susceptibility, it is a uniaxially oriented molded body. Can be molded. Moreover, even if any two of the magnetic susceptibilities are the same and the organic susceptibility is higher than that of the other susceptibility, a molded body that is uniaxially oriented in the fiber axis direction is molded. it can. In addition, a uniaxially oriented molded body can be molded regardless of a ferromagnetic material, a paramagnetic material, or a diamagnetic material.

Hereinafter, the present invention will be described in more detail with reference to examples.
A uniaxially oriented molded body was produced using α silicon nitride. α-silicon nitride is a paramagnetic substance belonging to the hexagonal system, and the magnetic susceptibility in the a-axis direction and the b-axis direction is substantially equal, and the magnetic susceptibility in the c-axis direction is smaller than the magnetic susceptibility in the a-axis direction and the b-axis direction. It is a substance that has conventionally been unable to obtain a uniaxially oriented molded body by a slip casting method by applying a fixed magnetic field.
Using the apparatus shown in FIG. 4, a slurry is made of powder composed of α-silicon nitride single crystal particles, placed in a gypsum mold, and a magnetic field is applied while rotating the mold to form a molded body. The obtained molded body was sintered under no magnetic field.

An example in which no seed crystal is added will be described.
A slurry of 65 wt% α silicon nitride (αSi ₃ N ₄ ) powder and 0.5 wt% tetramethylammonium ((CH ₃ ) ₄ N) surfactant mixed with 35 g of distilled water was mixed with sodium hydroxide. The solution was sufficiently stirred and mixed while maintaining the pH at 11.5, and further ultrasonic waves were applied for 30 minutes to sufficiently knead. The obtained slurry was poured into a porous mold, and the mold was formed by performing slip casting while applying a strong magnetic field (10 T) in the horizontal direction using a superconducting coil while rotating the mold at a speed of 6.25 minutes. Thereafter, the obtained molded body was sufficiently dried at 70 ° C. and then sintered at 1650 ° C. for 1.5 hours in the absence of a magnetic field to obtain a crystal oriented body.

FIG. 5 is a diagram showing a comparison between an X-ray diffraction image of a molded body obtained by the method of the present invention and a molded body obtained by a conventional method.
The conventional method differs from the method of the present invention only in that the mold is not rotated. Moreover, the X-ray-diffraction measurement was measured about the upper surface and side surface of the molded object, respectively. FIG. 5A is an X-ray diffraction pattern of the upper surface and the side surface of the molded body according to the conventional method. FIG. 5B is an X-ray diffraction pattern of the upper surface and the side surface of the molded body obtained by the method of the present invention.
FIG. 5A shows that the X-ray diffraction pattern of the molded body according to the conventional method has almost no difference between the upper surface and the side surface, and it is understood that there is no orientation. On the other hand, from FIG. 5 (b), in the molded product according to the present invention, the number of diffraction peaks decreases, and on the top surface, diffraction peaks based on the a and b planes are slightly seen, but diffraction peaks based on the c plane are apparent. It turns out that it has become. On the side surface, it can be seen that the diffraction peak based on the c-plane is small, and the peaks indicating the a- and b-planes are more obvious. From this result, it can be seen that according to the method of the present invention, a uniaxially oriented molded body can be molded.

FIG. 6 is a diagram showing a comparison of electron microscope (SEM) images of the upper surface and side surfaces of a molded body obtained by the method of the present invention and a molded body obtained by a conventional method. 6A is an SEM image of the upper surface and the side surface of a molded body produced by a conventional method using a fixed magnetic field, and FIG. 6B is an SEM image of the upper surface and side surface of the molded body produced by the method of the present invention. .
From FIG. 6A, it can be seen that there is no significant difference between the upper surface and the side surface of the molded body produced by the conventional method. On the other hand, from FIG. 6B, many hexagonal c-planes are seen on the upper surface of the molded body produced by the method of the present invention, and the tendency of c-plane orientation can be seen. In addition, a large number of single crystal grains with a-plane and b-plane orientation are seen on the side surfaces. From these results, it can be seen that according to the method of the present invention, a uniaxially oriented molded body can be molded.

Next, examples in which seed crystals are added will be described.
55 wt% α silicon nitride (αSi ₃ N ₄ ) powder, 35 wt% β silicon nitride (βSi ₃ N ₄ ) powder, and 0.5% tetramethylammonium ((CH _{3) 4} N) mud-like slurry obtained by mixing the surfactant thoroughly stirred mixture while maintaining the 11.5 pH with sodium hydroxide solution, applying further ultrasound for 30 minutes to sufficiently kneaded.
The obtained slurry was poured into a porous container, and the container was formed by slip casting while applying a strong magnetic field (10 T) using a superconducting magnet while rotating the container at a speed of 6.25 minutes per rotation. Thereafter, the obtained molded body was sufficiently dried at 70 ° C. and then sintered at 1650 ° C. for 1.5 hours in the absence of a magnetic field to obtain a molded body.

FIG. 7 is a view showing SEM images of the upper surface and side surfaces of a molded body produced by the method of the present invention to which a seed crystal is added. FIG. 7A is an SEM image of the upper surface and the side surface of the molded body prepared by a conventional method using a fixed magnetic field, and FIG. 7B is an SEM image of the upper surface and the side surface of the molded body manufactured by the method of the present invention. It is.
From FIG. 7A, it can be seen that there is no significant difference between the upper surface and the side surface of the molded body produced by the conventional method. On the other hand, from FIG. 7B, many hexagonal c-planes are seen on the upper surface of the molded body produced by the method of the present invention, and the tendency of c-plane orientation can be seen. In addition, a large number of single crystal grains with a-plane and b-plane orientation are seen on the side surfaces. From these results, it can be seen that according to the method of the present invention, a uniaxially oriented molded body can be molded.
FIG. 8 is a view showing X-ray diffraction images of the upper surface and the side surface of a molded body produced by the method of the present invention to which a seed crystal is added. FIG. 8 shows that the types of diffraction peaks are reduced compared to FIG. In addition, it can be seen that the diffraction peaks based on the c-plane (002) and the lattice plane (101) close to the c-plane are more apparent than those in FIG. In addition, on the side surface, it can be seen that the diffraction peaks based on the a-plane (200) and the lattice plane (210) close to the a-plane are more obvious than in FIG. From these results, it can be seen that the addition of the seed crystal further increases the uniaxial orientation.

Next, an example in which collagen fibers are uniaxially oriented will be described.
Collagen is a fibrous organic material that has the same magnetic susceptibility of any two and has a magnetic susceptibility higher than that of the other one. Conventionally, collagen has a fiber axis aligned in the direction perpendicular to the substrate. A molded body could not be obtained.
At 4 ° C., 1 cc of a buffer solution (MEM) was added to 10 cc of TypeLA collagen 0.2% aqueous solution (PH = 3) and stirred well, and then a small amount of an indicator (trade name: 10 × MEM, manufactured by Hanks) was dropped. Neutralized with sodium oxide solution. This solution was poured into a glass cell (height 30 mm, width 27 mm, thickness 1 mm). Under a 10 Tesla horizontal magnetic field generated using a superconducting magnet, this cell was allowed to gel for 2.5 hours while rotating 3 times a minute around the height direction in an atmosphere of 37 ° C. It was.

  FIG. 9 is a photograph obtained by observing a vertical surface (surface formed by height and width) of a gelled sample of an aqueous collagen solution prepared by the method of the present invention with a phase contrast microscope. It can be seen that the collagen fibers are oriented perpendicular to the horizontal applied field surface.

  The above embodiment is an example showing the effectiveness of the present invention, and does not limit the present invention. For example, in addition to the above examples, for example, a bioceramic material made of hydroxyapatite whose crystal plane is oriented to improve corrosion resistance, wear resistance, and fusion with the living body, and high corrosion resistance and wear resistance. A metal material having a crystal plane oriented, and a thermoelectric material having a crystal orientation so as to increase the conversion efficiency between heat energy and electric energy can also be realized. In addition, a composite material consisting of collagen and hydroxyapatite, which is expected as a biomaterial, produces a material in which the crystal orientation of collagen and hydroxyapatite has the same orientation as that found in mammalian teeth and bones. It is also possible to do.

According to the present invention, it is possible to form a uniaxially oriented molded body from powders of almost all substances, regardless of whether they are inorganic or organic, so that the crystal planes of these substances, or the crystal axis direction specific to the thermal, A molded article having optical, chemical, electromagnetic, physicochemical or mechanical properties can be provided at a low cost.
Further, since an organic substance having fiber axis anisotropy can be oriented in the fiber axis direction to form a molded body, for example, a fiber axis oriented molded body having a bone, tooth or cartilage shape made of collagen can be obtained. After forming and culturing cells on this molded body, it can be used as artificial bones, teeth or cartilage with extremely good biocompatibility.

It is a figure which shows the definition of the surface in the slip casting method by fixed magnetic field application. The figure shows the orientation state when a particle having crystal magnetic anisotropy is molded by slip casting by applying a fixed magnetic field, with the orientation planes appearing on each surface of the molded body, and the magnetic susceptibility in the crystal triaxial direction. The difference in orientation state due to the size relationship is shown. It is a figure explaining the principle of the method of this invention. It is a schematic cross section which shows the structure of the shaping | molding apparatus using the rotating magnetic field of this invention. It is a figure which compares and shows the X-ray-diffraction image of the molded object obtained by the method of this invention with the molded object obtained by the conventional method. It is a figure which shows the electron microscope image of the upper surface and side surface of the molded object by the method of this invention compared with the molded object by the conventional method. It is a figure which shows the SEM image of the upper surface and side surface of a molding which were produced by the method of this invention which added the seed crystal. It is a figure which shows the X-ray-diffraction image of the upper surface and side surface of the molded object produced by the method of this invention which added the seed crystal. It is the photograph which observed the perpendicular surface of the gelatinized sample of the collagen aqueous solution produced by the method of this invention with the phase-contrast microscope.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molding body 2 Magnetic field application direction 3 Gravity direction 4 Upper surface 5,6 Side surface 10 Crystal particle 20 Uniaxially oriented molded body molding device 21 Superconducting coil 22 Mounting table 23 Mud or suspension 24 Porous mold or mold container

Claims (13)

  Either of the two magnetic susceptibilities and the magnetic susceptibility of the material particles having crystal magnetic anisotropy larger than that of the other magnetic susceptibility are put in a porous mold, and the above is performed by the slip casting method. A molding method for a uniaxially oriented molded body, wherein a molded body made of a material is molded while applying a rotating magnetic field.   A suspension of material particles having crystal magnetic anisotropy in which any two magnetic susceptibilities are equal and whose magnetic susceptibility is larger than that of the other magnetic susceptibility is held in the mold container. A method for molding a uniaxially oriented molded body, wherein a molding is made while applying a rotating magnetic field when a molded body made of the above-mentioned substance is molded by evaporating a solvent component.   Any two of the magnetic susceptibilities are equivalent, and these magnetic susceptibilities are held in a mold container with a suspension made of a fibrous material having a magnetic anisotropy greater than that of the other magnetic susceptibility. A method for molding a uniaxially oriented molded body, characterized in that when a molded body made of the above-mentioned substance is molded by evaporating the solvent component of the liquid, the molded body is molded while applying a rotating magnetic field.   A suspension made of a fibrous material having magnetic anisotropy that is equal to any two magnetic susceptibilities and whose magnetic susceptibility is larger than that of the other magnetic susceptibility is placed in a porous mold. A molding method for a uniaxially oriented molded body, wherein a molded body made of the above-mentioned substance is molded by slip casting while applying a rotating magnetic field.   A rotating magnetic field is produced when an organic substance having the same magnetic susceptibility and any one of the two magnetic susceptibility is crystallized by a chemical reaction to form a molded body made of the above-mentioned substance. A method for molding a uniaxially oriented molded body, wherein a molded body made of the above-mentioned substance is molded while applying an electric field.   The uniaxially oriented molded body according to claim 1 or 2, wherein the slurry of material particles having crystal magnetic anisotropy is a slurry prepared by applying a shearing force while adding a peptizer. Molding method.   The uniaxial orientation according to claim 1, wherein a seed crystal that promotes crystal growth of the substance is added to the slurry or suspension, and then molded, and subsequently sintered. Molding method of molded body.   The uniaxial orientation according to any one of claims 1 to 5, wherein the rotating magnetic field is applied by rotating the porous mold or mold container in the same plane in a uniform magnetic field. Molding method of molded body.   6. The rotating magnetic field is applied by fixing the porous mold or mold container and rotating the direction of the applied magnetic field in the same plane. Method of molding a uniaxially oriented molded body.   The method for molding a uniaxially oriented molded body according to any one of claims 1 to 5, wherein the rotating magnetic field is a rotating magnetic field of 2 Tesla or more generated by a superconducting coil.   A uniaxial orientation comprising a coil arranged so that a magnetic field direction is horizontal, and a mounting table arranged in the coil and mounted on a porous mold or a mold container and rotated in a horizontal plane. Molding device molding equipment.   The uniaxially oriented molded body molding apparatus according to claim 11, wherein the coil is a superconducting coil.   The apparatus for forming a uniaxially oriented molded body according to claim 11, wherein the mounting table includes a heating unit.