JPS5928963B2 - Oriented sintered body and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oriented sintered body and a method for manufacturing the same.

The purpose is to create a sintered body in which specific crystallographic orientations of microcrystalline particles are aligned along an arbitrarily shaped surface that is not on the same plane and approximately perpendicular to the surface;
To provide a method suitable for manufacturing such a sintered body, a substance in which the specific crystal orientation of the particles constituting the substance is aligned in a certain direction is called a substance with a fibrous structure. As an example, a material obtained by rolling a metal plate is known.

However, the orientation of a metal plate subjected to such rolling processing is low, and the range of its application is extremely limited. According to the present invention, it is possible to easily produce a sintered body that exhibits a constant orientation not only on a flat surface but also on a complex curved surface, and a high degree of orientation obtained thereby. It is possible to provide a sintered body with properties.

The sintered body as used in the present invention has a structure as shown in FIG. It refers to something that is aligned perpendicular to the surface of the lever.

Here, being perpendicular to the surface of the sintered body means being perpendicular to the tangential plane of the curved surface. A sintered body with such orientation exhibits various properties depending on the material that constitutes it, and its special orientation opens up new uses.

It is well known that single crystals generally have different physical and chemical properties depending on their crystal orientation.

Such properties include, for example, mechanical strength, abrasion resistance, electrical conductivity, thermal conductivity, refractive index, and corrosion resistance. However, in a sintered body, although each of the microparticles that make up the body has the above-mentioned properties, the crystal orientation of each particle is disordered or close to disordered.

However, when looking at the sintered body as a whole, it is homogenized and exhibits almost no anisotropy. If the crystal orientation relative to the surface is, for example, in a corrosion-resistant direction, it is possible to create containers that are extremely chemically stable.

Furthermore, if the crystal orientation matches the direction of good thermal conductivity, it is suitable for use as a container for housing a heat sink or a structure that generates heat, such as a transistor. On the other hand, if it coincides with the direction of poor thermal conductivity, it can be used as a heat insulating box, for example. Products exhibiting these properties are
The present invention, which cannot be realized with a general sintered body or made with a single crystal, will first be explained from the manufacturing method.

The structure of the sintered body according to the present invention will be understood from the description of this method. In advance, a portion of the mold corresponding to the desired orientation of the sintered body is made of a material exhibiting water permeability.

Here, water permeability means exhibiting the property of permeating liquid. On the other hand, a powder having powder anisotropy is prepared as a raw material, and a slurry of this powder is made. Powder anisotropy as used in the present invention refers to the property of aligning the orientation of powder when it is pressurized. There is something I did. Although it is desirable that the powder anisotropy exists in all of the raw material powder, a sufficient degree of orientation can be obtained even if it exists in only a part of it. A slurry of powder exhibiting such compacted powder anisotropy is placed in the mold and press-molded.

During pressurization, most of the liquid contained in the slurry is leaked out of the system through the water-permeable parts of the mold. The obtained molded body is fired to obtain a desired sintered body. As the material exhibiting water permeability, porous ceramics made of alumina, forsterite, etc., and porous molded products made by powder molding can be used.

Furthermore, porous glass materials made by fusing glass bulbs or glass fibers at low temperatures can also be used.
Such materials are generally considered to have low mechanical strength, but according to the inventor's experiments, it is possible to make molds that can withstand pressures of 500k9/CTl. 2-10t/Cr depending on the sintering method! It is also easy to make something that can withstand a pressure of 1. The severity of the pressure for molding varies depending on the properties of the powder exhibiting powder anisotropy, but 1
It is sufficient if the range is from 001<9/ to 5t/d.

For example, in the case of thin plate-like α-Fe2O3 particles with a diameter of about 10 μm, a molded body with extremely good orientation can be produced at a pressure of 100k9/CTil. Also, 0.3 to 1μ
In the case of acicular goethite particles with a length of 2 to 5 t/
CT! Orientation can be achieved by applying a pressure of 1. Examples thereof will be described below.

Figure 1 shows, for example, a bowl-shaped container made of a sintered body, in which the grain crystals are aligned in a fixed direction with respect to the surface as shown by the arrows. Made.

In the figure, 1 is a female mold, made of porous material.
Reference numeral 2 denotes a protective member, which is installed to prevent excessive tensile stress from being applied to the female mold 1 made of a porous material, and is provided with a plurality of through holes in advance.

3 is an upper punch, and a powder 4 having vζ powder anisotropy is filled between this and the female mold 1.

In such a configuration, when pressure is applied to the upper punch 3, the liquid contained in the powder 4 passes through the female die 1 and is discharged to the outside through the through hole of the protection member 2. The obtained molded product generally has good orientation, and when sintered under appropriate conditions, the orientation becomes even better, making it possible to produce a sintered body as shown in FIG. Next, the manufacturing method will be described in detail with reference to examples thereof. [Example 1] As shown in Fig. 3, female mold 1 made of forsterite
1 is stored in the protective box 12, and the slurry 13 is placed in the female mold 11.
I put it in.

The upper punch 14 was fitted into the female mold 11 with the clamp 9, and pressure was applied thereto to apply a single pressure of the slurry 13. Slurry 1
As No. 3, a thin plate-like α-Fe2O3 exhibiting powder anisotropy and a needle-shaped γ-MnOOHl ZnO powder exhibiting no compact powder anisotropy were mixed and smelted with water. α-F
The particles of e2O3 powder have a diameter to thickness ratio of 10:1,
The average particle size is 15μ. The moles of each powder were equimolar. By pressurizing the upper punch 14, half of the water contained in the slurry 13 permeated through the female mold 11 and was discharged through the through hole of the protective box 12.

In this way, after molding into a rectangular parallelepiped shape at a pressure of 500k9/d, this molded body was heated to 350k9/CT at 1350°C.
Sintering was performed for 4 hours while applying pressure ii. The average grain size of the obtained sintered body was 150 μC. When the above sintered body was examined by X-ray diffraction, it was found that the crystals in the cross section were <111
〉The axes were arranged as shown in Figure 4.

The orientation of the 111 plane at the bottom surface 2L of the sintered body, that is, along the plane perpendicular to the pressing direction of the upper punch 14 is 100 ft.
), and the orientation on the side was approximately 95(f).
In addition, the parts without arrows in the figure are 111〉
This indicates that the direction of the axis is disordered. The orientation was calculated using the characteristic X-ray Feka of Fe, by irradiating the sample surface with X-rays, determining the integrated intensity of diffraction lines with a black angle of 85 degrees or less, and using the following formula.

t In the above formula, 11 is the integral value of the intensity of all diffraction lines,
1 indicates the sum of the integral values of the diffraction line intensities on the 111th plane, the 222nd plane, and the 333rd plane.

The subscripts A and R represent factors for oriented sintered bodies and non-oriented sintered bodies, respectively. [Example 2] Using a press mold having the structure shown in Fig. 2, a thin plate of α-Fe with a diameter to thickness ratio of about 10:1 and a particle size of about 16 μm was prepared.
A slurry of 2O3 was molded under pressure.

The applied pressure was 1 ton/Crl. The obtained molded body was placed in a nitrogen atmosphere and sintered at a temperature of 1400° C. for 4 hours while applying a pressure of 300 kg/C7i. The average grain size of the sintered body was 60μ, and a dense one was obtained. The orientation at the bottom portion of the sintered body was approximately 95(f), and the orientation at the side portions was approximately 90%.

The orientation was measured in the same manner as in Example 1, and calculated using the following formula. Here, 1110 and 1006 represent the integral value of the diffraction line intensity by the 110 plane and the integral value of the diffraction line intensity by the 006 plane, respectively.

As explained above, according to the present invention, it is possible to provide a sintered body that exhibits a high degree of orientation along the surface, and it is possible to realize new applications that cannot be realized with single crystals or conventional sintered bodies. .

Moreover, such a special sintered body can be produced relatively easily.

[Brief explanation of drawings]

FIG. 1 shows the structure of an embodiment of the oriented sintered body of the present invention, and FIG. 2 shows the structure of an apparatus for producing the same. FIG. 3 illustrates the structure of an apparatus for carrying out the manufacturing method of the present invention, and FIG. 4 shows the structure of a sintered body obtained by the apparatus. 1,11...Water permeable type, 4,13
・・・・・・Slurry of compacted anisotropic powder, 3, 14...
...Upper punch.

Claims (1)

[Scope of Claims] 1. Orientation characterized by aligning a specific crystallographic orientation of microcrystalline particles along an arbitrarily shaped surface that is not on the same plane and approximately perpendicular to the surface. Sintered body. 2 Using a mold made of a material that exhibits water permeability at least in part, a slurry of powder with compaction anisotropy is pressure-molded, and a specific crystallographic orientation of microcrystalline particles is formed into a molded product. A method for producing an oriented sintered body, which comprises aligning the molded body along the surface of the body and at a substantially right angle to the surface, and then sintering the molded body.