JPH09248443A - Ultrahigh pressure generation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the friction force with the piston hole acting on a piston element to the utmost and to accurately detect deformation data under ultrahigh pressure. SOLUTION: A conical recessed part 13 is formed to the leading end of an anvil 1 into which a piston element 8 is inserted and filled with a large number of spheres 20 so as to surround a piston element 8 and a soft substance 30 is placed on a sphere group. The soft substance 30 enters the gaps between the spheres at a time of pressurization but is prescribed by the gaps between the spheres to lower in pressure and does not reach the bottom part of the recessed part and, therefore, the leak of a pressure medium is sealed by the soft substance 30 and, since the piston element and the spheres 20 are in a spherical surface contact state, friction is reduced. As a result, the deformation data of a sample X can be accurately detected.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultrahigh pressure generator. More specifically, the present invention relates to an ultra-high pressure generator used for synthesizing diamond and cubic boron nitride and for testing the deformation characteristics of a substance under ultra-high pressure.

[0002]

2. Description of the Related Art In an ultrahigh pressure generator, there has been no example developed so far for testing the deformation characteristics of a substance under ultrahigh pressure. All of the conventional ultrahigh pressure generators are for synthesizing diamond and the like, and the prior art having a structure similar to the present invention is as follows.

In general, there are types such as a piston cylinder type and an anvil cylinder type as a device for generating an ultrahigh pressure. In each of these, an ultrahigh pressure generating chamber is formed in the center, and a pyrophyllite, etc. is formed in the ultrahigh pressure generating chamber. Is filled with a pressurized medium, and the pressurized medium is compressed with a pressurized anvil to generate an ultrahigh pressure. That is, as shown in FIG. 8, the conventional apparatus of this type surrounds the pressurizing medium 102 with a plurality of anvils 101 to form an ultra-high pressure generating chamber containing the pressurizing medium 102, and the anvil 101 is directed toward the center. Then, it is pushed forward by pressure, and thereby an ultrahigh pressure is generated.

However, when the anvil 101 is pushed forward and moved from the position shown by the solid line to the position shown by the dotted line, the pressurizing medium 102 is also compressed as shown by the dotted line from the position shown by the solid line to the above-mentioned space in the gap of the anvil 101. A protruding portion (a) of the pressurizing medium 102 is formed, and when the anvil 101 is further pushed by pressure, the protruding portion (b) of the pressurizing medium 102 is formed as shown by a one-dot chain line diagram. The compression of the protruding portions (a) and (b) by the anvil 101 is considerably larger than the compression of the central pressurizing medium 102, and the more the anvil 101 is pushed in order to generate the super high pressure, the larger this ratio becomes. . Therefore, in the conventional apparatus shown in FIG. 8, the pressure applied to the anvil 101 consumes a large amount of loss in the protruding portions (a) and (b), and the gap between the anvils 101 is considerably small. However, there is a drawback that the above loss rapidly increases.

The ultra-high pressure generator of Japanese Patent Publication No. 47-50258 is
It is intended to eliminate the above-mentioned drawbacks, and is configured as shown in FIG. Reference numeral 201 is a pressure anvil, 202 is a fixed anvil, and 203 is a cylinder (anvil). The pressure anvil 201 and the fixed anvil 202 are arranged above and below the cylinder 203 so as to be opposed to each other, and surrounded by these to provide a calculus in the center. Form a super high pressure generating chamber filled with a pressurizing medium 204 such as. 205 is a piston body, which is inserted into the piston hole 208 of the pressure anvil 201. 206 is a piston body 205
The pressure anvil 20 with the plug for forming the pressure cylinder of
It is screwed to 1. 207 is a pressure cylinder of the pressure anvil 201. In this conventional example, the pressurizing anvil 201 and the piston body 205 have two pressurizing means as described above. First, the pressurizing anvil 201 pressurizes to a predetermined position and then the piston body 205 pressurizes. Then, the pressurizing medium 204 that has protruded by the initial pressurization by the pressurizing anvil 201 has a function of a gasket at the position where the pressurizing anvil 201 stops pushing, and the extruding member is extruded at the next pressurization by the piston body 205. Only the central pressurizing medium 204 continues to be pressurized without expanding the part (a), and a desired ultrahigh pressure is generated. Therefore, the protruding portion of the pressurizing medium 204 is reduced, and the pressure loss due to the compression of the protruding portion is not increased.

However, the piston hole 20 of this conventional example
The device in which the piston body 205 is inserted in 8 has the following problems. That is, if the clearance between the piston hole 208 and the piston body 205 is as small as possible, the force required for the deformation of the sample body under ultrahigh pressure cannot be accurately measured due to the friction or the binding force between the piston hole 208 and the piston body 205. If it is too large, the sample body enters the above clearance when the ultra high pressure is generated, and it becomes difficult to form the ultra high pressure space.The sample body that enters the clearance causes the piston body 205 to exert a frictional force. The accuracy of the obtained measurement data will be impaired.

[0007]

SUMMARY OF THE INVENTION In view of the above situation, the present invention reduces the frictional force and the restraining force acting on the piston body with the piston hole as much as possible to easily generate the super high pressure, and the deformation under the super high pressure. It is an object of the present invention to provide an ultrahigh pressure generator capable of detecting data with high accuracy.

[0008]

An ultrahigh pressure generator according to claim 1 is surrounded by a plurality of anvils to form an ultrahigh pressure generation chamber, and a piston is provided in one of the anvils toward the ultrahigh pressure generation chamber. An ultrahigh pressure generator in which a hole is formed, and a piston body that is moved to the side of the ultrahigh pressure generation chamber by an external force is inserted into the piston hole, wherein the piston body is concentric with the piston hole at the tip of the anvil. While forming a conical concave part of the conical concave part, a large number of spheres are filled in the conical concave part so as to surround the piston body, and a soft substance is placed between the sphere group and the ultrahigh pressure generating chamber. Characterize.
The ultrahigh pressure generator of claim 2 is characterized in that a small sphere is further inserted into a gap between the spheres filled in the conical recess. According to a third aspect of the present invention, the ultrahigh pressure generating device is characterized in that a powder is filled in a gap between the spherical bodies filled in the conical recess. The ultrahigh pressure generator according to claim 4 is characterized in that a gap between the spherical bodies filled in the conical recess is filled with a soft substance.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an anvil structure of an ultrahigh pressure generator according to an embodiment of the present invention, and FIG.
FIG. 3 is an explanatory view of the sealing action in the anvil structure of FIG. 3, FIG. 3 is an explanatory diagram of the sealing action in another anvil structure, FIG. 4 is an overall view of the ultra-high pressure generating device, and FIG. 5 is a perspective view of main parts of the upper and lower anvils and side anvils. .

First, FIG. 4 to FIG.
5, the upper anvil 2 and the lower anvil 1 have a pair of upper and lower anvils 1 and 2 each having a tapered truncated pyramid-shaped tip, and the end face of the tip is It is arranged to face each other. Reference numeral 3 denotes a side anvil disposed at an intermediate position between the anvils 1 and 2 and, like the anvils 1 and 2, has a tapered quadrangular truncated pyramid-shaped tip portion. The anvils 3 are arranged in front, back, left and right (the front side anvils are not shown in FIG. 5), and the end faces of the tip portions thereof and the end faces of the tip portions of the pair of upper and lower anvils 1 and 2 serve to compress the object to be compressed. An ultrahigh pressure generation chamber 4 which is a space for entering is formed. Reference numeral 5 is an upper ram for driving a piston body 8 described later, and 6 is a lower ram for driving the lower anvil 2. The pair of upper and lower anvils 1 and the pair of upper and lower rams 5 and 6 are coaxially attached to the press frame 7 with their centers aligned with the axis y. Further, one of the pair of upper and lower anvils 1, in the illustrated example, a piston hole is formed in the upper anvil 1 concentrically with the axis y, and the piston body 8 is inserted. The side anvil 3 pressurizes the pressurizing medium 45 contained in the ultra-high pressure generating chamber 4 by a pressurizing device such as a ram (not shown), and ascends by half the amount of movement of the lower anvil 2 by the ram 6 and the center direction. It is configured to move to.

The anvil structure of the upper anvil 1 having the piston body 8 will be described in detail with reference to FIG. As described above, the tip of the anvil 1 is a truncated pyramid having a truncated pyramid shape, and has an outer conical surface slope 11 and a head 12. Further, a piston hole 9 is bored concentrically with the axis y, and a conical recess 13 is formed concentrically with the piston hole 9 by performing a counterbore processing from the head 12 toward the piston hole 9.

A spherical body 20 is filled in the bottom portion of the conical recess 13 so as to surround the piston body 8. This sphere
Since 20 acts on high pressure, a material such as ceramic or cemented carbide is preferable, and in order to reduce the pressure of the soft substance described later, the smaller the gap between the spheres, the better.
A diameter of 0.2 to 0.5 mm is suitable. A soft substance 30 is placed on the upper surface of the filled sphere 20 (between the sphere 20 and the ultrahigh pressure generating chamber 4).
Is placed and covers the upper surface of the sphere group. This soft material
30 is a substance that becomes liquid at high temperature and high pressure, for example,
Lead or the like is preferable.

A pressure medium 45 made of pyrophyllite, sodium chloride (Nacl), stabilized zirconia (ZrO2) or the like is inserted into the ultrahigh pressure generation chamber 4, and the piston body 8 is inserted into the pressure medium 45. A sample insertion hole 46 is formed in the axial direction, the sample X is placed in the center of the sample insertion hole 46, and the round rod-shaped sub-piston 10 is inserted above and below the sample X. This sub piston 10
Is required to have heat resistance and pressure resistance, and for example, alumina, ceramics, cemented carbide and the like are suitable.

In the ultra-high pressure generator described above, the pressurizing medium 45 in the ultra-high pressure producing chamber 4 is pressurized by the anvils 1, 2 and 3, and the piston body 8 is inserted into the trial insertion hole 46 of the pressurizing medium 45. (Or the phantom line), the substance (or sample X) can be pressurized to an ultra-high pressure state via the sub piston 10, and diamond, cubic boron nitride, etc. can be synthesized,
Alternatively, it is possible to test the deformation characteristics of the sample X when the piston body 8 enters.

In the material synthesis or deformation characteristic test as described above, when the sample X inserted in the pressurizing medium 45 in the ultrahigh pressure generating chamber 4 is pressurized by the anvils 1, 2, and 3,
The anvil structure of this device exhibits a sealing action as shown in FIG. That is, when the ultrahigh pressure P applied to the pressurizing medium 45 acts on the soft substance 30 by a reaction, the soft substance 30 tries to enter the gap between the spheres 20 (see the arrow). Since the entering direction can be changed vertically and horizontally by each sphere 20, the pressure of the soft substance 30 decreases each time it passes through the gap. Such a phenomenon occurs each time when passing between the stacked spheres 20, and is also affected by the viscosity of the soft substance 30, so that the soft substance 30 hardly enters the space between the next spheres 20.
Therefore, the soft material 30 is filled and stacked in spheres.
It can be sealed so that the pressurizing medium 45 does not enter the piston hole 9 without reaching the bottom of 20.

On the other hand, as shown in FIG. 1, since the piston body 8 and each spherical body 20 are in spherical contact, the frictional force acting is small, and the forward movement of the piston body 8 is hardly restrained. Therefore, the detection accuracy of the deformation data of the sample X obtained by the experiment is also improved, and the data close to the actual one can be obtained. Further, the clearance between the piston body 8 and the piston hole 9 can be increased, and the friction between the piston body 8 and the piston hole 9 is reduced, so that the piston body 8 can be stably moved. Therefore, the loss of the piston driving force due to friction or the like is reduced, and for this reason, the data required for the deformation of the sample X under ultrahigh pressure can be accurately detected.

Next, the test procedure of the deformation characteristics under ultrahigh pressure by this apparatus will be described with reference to FIG. First, the sample X is inserted into the pressurizing medium 45 placed in the ultrahigh pressure generating chamber 4, and the lower ram 6
Is operated to drive the lower anvil 2 to generate the desired ultrahigh pressure in the pressurizing medium 45 (see symbol a). Next, the pressure of the upper ram 5 is increased until the piston body 8 starts to operate (see symbol b). Then, while the pressure of the upper ram 5 is maintained in the state at the time when the piston body 8 starts to operate, when the operation of the piston body 8 stops (see the reference sign c), decompression starts conversely. When the piston body 8 starts to move again (see reference numeral d), the pressure reduction of the upper ram 5 is stopped and the pressure is maintained. Further, at the time when the operation of the piston body 8 is stopped (see reference numeral e),
The test is completed by reducing the pressure of the lower ram 6 and the upper ram 5.

By measuring the pressures Pi and Pf required for the operation of the piston body 8 during this test, the deformation resistance of the sample X under ultrahigh pressure can be obtained. And the above pressures Pi, Pf
In this device, since the frictional force and the restraining force generated when the piston body 8 is driven are almost equal to zero as described above in this device, it is possible to accurately measure the deformation data with less error.

Next, another embodiment of the present invention will be described. In the above-described embodiment, the ultrahigh pressure generating device including the upper and lower anvils 1 and 4 and the four side anvils 3 has been described, but as shown in FIG. 7, a pair of upper and lower anvils having a tapered truncated cone-shaped tip portion. It can also be applied to an ultra-high pressure generator in which a hollow anvil (hollow cylinder) 53 having a hole 54 in the center is arranged between 51 and 52. The hollow anvil (hollow cylinder) 53 may be provided with conical recessed grooves corresponding to the truncated cone-shaped tips formed on the anvils 51 and 52, respectively.

In the embodiment shown in FIG. 1, the spheres 20 are all of the same size, but small spheres 20b having a small diameter may be inserted between the spheres 20 as shown in FIG. in this case,
Since the gaps between the spheres 20 are reduced by the small spheres 20b, there is an advantage that the sealing effect is further enhanced.

The small sphere 20b in the embodiment of FIG.
Alternatively, a powder or soft material may be inserted. As a powder, a stable material that does not physically or chemically change with pressure or temperature, such as magnesium oxide (MgO 2).
Is preferable, and as the soft substance, granular lead or the like is preferable. Even in the embodiment in which the powder or the soft material is inserted, the gap between the spheres 20 is small, so that there is an advantage that the sealing effect is also enhanced.

[0022]

According to the first to fourth aspects of the present invention, the loss of the piston driving force is small, and the frictional force with the anvil acting on the piston and the restraining force can be reduced as much as possible. It becomes possible to synthesize, and the deformation data under ultrahigh pressure can be detected with high accuracy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an anvil structure of an ultrahigh pressure generator according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a sealing action in the anvil structure of FIG.

FIG. 3 is an explanatory diagram of a sealing action according to another embodiment of the present invention.

FIG. 4 is an overall view of an ultrahigh pressure generator.

5 is an exploded perspective view of the anvil structure of FIG. 4. FIG.

FIG. 6 is an explanatory diagram of the procedure of a deformation characteristic test under ultrahigh pressure.

FIG. 7 is a perspective view of an anvil structure of an ultrahigh pressure generator according to another embodiment of the present invention.

FIG. 8 is an explanatory diagram of a problem of the conventional technique using an anvil having no piston.

FIG. 9 is a structural explanatory view of a prior art using an anvil having a piston.

[Explanation of symbols]

1 Upper anvil 2 Lower anvil 3 Side anvil 4 Ultra high pressure generating chamber 5 Upper ram 6 Lower ram 8 Piston body 9 Piston hole 10 Secondary piston 20 Sphere 30 Soft material 45 Pressurized medium

Claims (4)

[Claims] 1. An ultrahigh pressure generating chamber is surrounded by a plurality of anvils, a piston hole is formed in one of the anvils toward the ultrahigh pressure generating chamber, and an ultrahigh pressure is generated in the piston hole by an external force. An ultrahigh pressure generator in which a piston body moved to the chamber side is inserted, wherein a conical recess concentric with the piston hole is formed at the tip of the anvil into which the piston body is inserted, and in the conical recess. An ultrahigh pressure generating device, characterized in that a large number of spheres are filled so as to surround the piston body, and a soft substance is placed between the sphere group and the ultrahigh pressure generating chamber. 2. The ultrahigh pressure generator according to claim 1, wherein a small sphere is further inserted into a gap between the spheres filled in the conical recess. 3. The ultrahigh pressure generator according to claim 1, wherein a powder is filled in a gap between the spherical bodies filled in the conical recess. 4. The ultrahigh pressure generator according to claim 1, wherein a soft substance is filled in a gap between the spheres filled in the conical recess.