JP3275970B2 - Ultra high pressure and high temperature equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-high pressure and high temperature apparatus used, for example, for synthesizing and growing diamond and cubic boron nitride, and for producing a sintered body of diamond and cubic boron nitride.

[0002]

2. Description of the Related Art A piston-cylinder type ultra-high pressure high temperature apparatus is disclosed in US Pat. C. Research has been ongoing since the development by Professor Kennedy, but the scale of the device has not yet been successfully increased, and although it has been reported that the one-inch inner diameter of the cylinder is the largest device that has been put into practical use, it has been industrially successful. There is no report.

A typical device of this type according to the prior art is shown in FIG. In the figure, a cylinder 1 generally made of a WC-Co cemented carbide containing about 15% cobalt is shown.
Is provided with a shaft hole having a substantially constant diameter as a whole and a small inclination angle. Fixed piston 2 around the hole
And the lower compression ring 3 applies an axial compression load. When a pressure of 5.5 GPa required for diamond synthesis is generated in the reaction chamber by the movement of the lower piston 4 in the sample 5 in the reaction chamber, the pressure in the cylinder due to the pressure generation is opposed to the vertical stress caused by the Poisson effect. A load is applied to the upper and lower end surfaces of the cylinder to prevent damage to the cylinder. It is considered that the load value at this time is sufficient if the deformation due to the Poisson effect is canceled at the maximum. That is, Kenn with such a configuration is used.
The device by Prof. edy is based on the idea that, in order to prevent lateral cracking of the cylinder due to the Poisson effect, the stress generated by the Poisson effect is maximized and reinforced by external pressure. The design is such that the minimum required load is used to reinforce the cylinder in order to maximize the pressurized cross-sectional area of the reaction chamber as far as the capacity allows. Therefore, the cylinder is subjected to repeated pressurizing operation under the condition of the pressure limit, and the service life of the cylinder is only 100 times or less unless sufficient care is taken, so that it cannot be an economical synthesizer. In addition, it was impossible to increase the size of the apparatus.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to increase the number of times of use or to increase the pressure that can be generated by increasing the size and the pressure resistance of the cylinder which could not be achieved by the prior art apparatus. Accordingly, it is an object of the present invention to provide an apparatus capable of more economically performing a synthesis reaction under ultrahigh pressure.

[0005] In the piston-cylinder type ultra-high pressure and high temperature apparatus of the present invention, the cylinder is located inside the large-diameter cylindrical or conical portion and the large-diameter portion. A reduced diameter cylindrical portion, both of which are connected by a steep connection perpendicular to or near the axis. The piston, on the other hand, has a small and a large diameter essentially cylindrical or conical section in which at least one movable piston has a discontinuously decreasing diameter towards the tip, both of which are also perpendicular to the axis, or It is connected by a steep connection near this.

[0006] The large and small diameter portions of these cylinders and pistons more preferably have cylindrical wall surfaces essentially parallel to the axis, but within a range in which a sufficient pressure stroke is secured, And a conical shape having an inclination angle of about 15 °. In addition, a gasket material can be inserted into the fitting portion for the purpose of securing a stroke, electrical insulation, and the like.

In the present invention, an inorganic or organic substance which plastically flows under high pressure conditions, or an inorganic or organic substance thereof, flows into an annular space surrounded by a small-diameter portion and a connecting portion of a piston and a large-diameter cylindrical portion of a cylinder and an end face thereof. A pressurized medium consisting of the composite is filled and arranged. With this configuration, a load is applied to the piston from the outside by the pressurizing device, and when an ultra-high pressure is generated in the reaction chamber, the plastic pressurized medium simultaneously pressurized is applied to the piston in the radial direction. An axial compressive stress acts on the cylinder. These forces not only act to counteract and cancel the deformation of the piston and cylinder due to the Poisson effect when pressurized in the reaction chamber, but also to increase the compressive stress on the piston and cylinder by increasing the pressure. , It is possible to impart higher pressure resistance. Therefore, as the magnitude of the pressure generated in the plastic pressurizing medium,
Usually, a value of 0.2 to 0.3 of the pressure value generated on the piston tip surface and the cylinder inner wall surface is used. Higher pressures contribute as the compressive stress described above. Note that the upper limit of this force is theoretically defined by the compressive strength of the material constituting the piston and cylinder. On the other hand, even if the pressure value is smaller than the above value, the deformation of the piston and the cylinder is partially offset, so that a certain effect is obtained in that it contributes to the improvement of the service pressure or the service frequency of the device. Can be

[0008] From the above viewpoint, it is preferable that, for example, when a pressure of 6 GPa is generated in the reaction chamber, a pressure of about 2.5 GPa is generated in the plastic pressurizing medium. By doing so, in the device of the present invention, the upper limit value of the pressure that can be generated is higher than that of the conventional piston-cylinder device, and even in a method of generating a pressure of about 5.5 GPa required for diamond synthesis,
Since the relative pressure load is small, the effect of improving the life of the device can be obtained. By applying pressure to the end face of the small-diameter cylindrical part (sleeve) of the cylinder with a plastic pressurizing medium, it is possible to eliminate the need for axial stress support for the large-diameter cylindrical part (cylinder body) of the cylinder. Becomes

In the piston of the present invention, a small-diameter cylinder
The conical portion and the large-diameter cylindrical / conical portion connected by the connecting portion may be formed integrally or may be divided by a plane following the connecting portion. The constituent material is preferably a hard metal or a highly rigid material such as die steel or high-speed steel. Although the angle of the connecting portion can be arbitrarily set, it is preferable to use an angle between 0 and 40 ° for practical use. The piston in the device of the present invention may be a single-push type consisting of one or one of the above, or two or two
It can be used as a double push type consisting of a set.

[0010] The plastic pressurizing medium in the present invention includes:
Lead, tin, zinc, antimony, silver, gold, aluminum,
Indium, various alkali metals or alloys containing these as main components, wax (wax), clay, talc, Nacl, K
Halides of alkali metals such as Br, silver chloride, h
-BN, inorganic mixtures such as graphite, vinyl, polyethylene,
Organic compounds such as polypropylene and Teflon are used alone or in combination. Mixtures of graphite and oil are also mentioned as one suitable pressurized medium. In short, any material may be used as long as it is easily deformed by pressurization and generates a pressure close to the hydrostatic pressure in the pressurized medium container. In order to secure the pressure generation in the plastic pressurized medium and the movement of the piston with respect to the cylinder (pressurized stroke), use of the compressibility of the pressurized medium,
Means for discharging a part of the pressurized medium to a lower pressure space as needed is used.

In one configuration, the small-diameter cylindrical portion (sleeve) of the cylinder is divided into a large-diameter cylindrical portion (cylinder body) on the outer periphery, and the former is press-fit, shrink fit, cold fit, or the like. By means of (1), the latter is tightened in the circumferential direction and pre-pressurized. At this time, by arranging the lubricant in the contact portion between the two, the sleeve portion in contact with the reaction chamber, by a stress equal to or more than the Poisson effect applied to the end face by the pressurized medium, but less than the compressive strength of the material, Deformation due to pressure generated in the reaction chamber is suppressed. This configuration not only increases the reinforcement of the sleeve portion, but also generates a stress due to the Poisson effect on the inner wall of the sleeve portion, thereby improving the pressure resistance of the sleeve portion and the effect equivalent to pre-pressing the inner wall of the sleeve portion. Thus, an ultrahigh-pressure high-temperature apparatus capable of generating a higher pressure than the first invention apparatus can be obtained. In this case, the material of the sleeve portion that is in contact with the reaction chamber is preferably a cemented carbide as a general diamond synthesizer, but alloy steel can also be used. Further, alloy steel can be used as the material of the cylinder body at the outer peripheral portion.

In another configuration, a small-diameter cylindrical portion (sleeve) of a cylinder in contact with a reaction chamber is divided into a large-diameter cylindrical portion (cylinder main body) of an outer peripheral portion. At the same time, it is reinforced by being pressed into the cylinder body by the pressing force from the end face through the plastic pressurizing medium. With this configuration, a stronger sleeve is reinforced as compared to the above.

In the third configuration example, a small-diameter cylindrical portion (sleeve) in contact with the reaction chamber is divided into a large-diameter cylindrical portion (cylinder main body) in the outer peripheral portion, and the sleeve portion in contact with the reaction chamber is formed. The outer diameter is smaller than the inner diameter of the cylinder body at the outer peripheral portion, and the plastic pressurizing medium is disposed in the gap between the two cylindrical portions. With this configuration, the outer surface of the sleeve that is in contact with the reaction chamber during the pressurization is pressurized by the plastic pressurizing medium, and a compressive stress is generated on the inner surface of the sleeve in accordance with the inner-outer diameter ratio, thereby reinforcing the sleeve. Is made. For example, when the inner / outer diameter ratio of the sleeve in contact with the reaction chamber is 1: 3, the tensile strength is 250 kg / mm ²
An ultrahigh-pressure high-temperature device capable of generating an internal pressure of 5.6 GPa with the high-speed steel of the present invention. Thus, an ultrahigh-pressure high-temperature device capable of generating a higher pressure than the second configuration example can be obtained.

In the fourth configuration example, the pressure generated in the final reaction chamber is further increased by incorporating two, three or more similar devices in each of the above-mentioned devices, thereby reducing the pressure from graphite to diamond. 10GPa required for direct conversion reaction and binder-free diamond sintering
This makes it possible to generate the above ultrahigh pressure.

In any of the configurations, the ratio of the small diameter of the cylinder to the diameter of the large diameter cylindrical portion is 1.5 or more and 5 or less,
In practice, it is preferably 3 or less.

The present invention will be described with reference to the drawings. Figures 2-4
1 is a longitudinal sectional view of a main part in an axial plane, showing several examples of an ultra-high pressure and high temperature device configured according to the present invention. In the figure, a cylinder (shown as 20 as a whole) made of a highly rigid material and having a shaft hole in the center is located outward (lower).
Is formed in a substantially cylindrical shape, and the inner side has a cylindrical wall of a smaller diameter by projecting from the wall. The overhang is configured as part of the cylinder in FIG. 2 and as a sleeve 22 separate from the cylinder body 21 in FIGS. 3 and 4, and in particular in the configuration of FIG.
Between the cylinder body 2 and the cylinder body 21, a thin sleeve 23 made of a pressurized medium is sandwiched. The upper surface of the cylinder is beveled for reinforcement, while the lower surface is flat. On the upper surface, a fixed piston 24 is fitted to the upper surfaces of the cylinder 20, the cylinder body 21, and the sleeve 22. The movable piston 25 is positioned below and a small diameter cylindrical portion 27 mounted on a larger diameter cylindrical base 26 travels through the small diameter essentially cylindrical portion of the cylinder and pressurizes the reaction sample 28.

[0017]

[Embodiment 1] In the apparatus shown in FIG.
The inner diameter of the small-diameter cylindrical portion was 50 mm, and the inner diameter of the large-diameter cylindrical portion was 100 mm.
The end face of the small-diameter cylindrical portion of the cylinder, the (overhang) inner wall of the large-diameter cylindrical portion, and the space surrounded by the piston are filled with silver chloride, and the pressure generated in this portion is reduced by 200 mm.
By controlling the pressure to kg / mm ² , a high-pressure container withstanding a reaction pressure of 5.5 GPa was obtained.

[0018]

Embodiment 2 In the apparatus shown in FIG. 3, a WC-20 having an inner diameter of 50 mm was used as a small-diameter cylindrical portion (sleeve) of a cylinder.
% Co cemented carbide, piston is WC-10% Co
Made of cemented carbide. The inner diameter of the cemented carbide sleeve is 350k by the clamping ring of the pressure vessel of the large diameter cylindrical part (cylinder body) made of die steel with an inner diameter of 130mm.
A preload of g / mm ² was applied to the container to withstand a pressure of about 5.3 GPa. By filling lead in the space in contact with the end surface of the sleeve and the side surface of the piston, and setting the pressure of the lead to 200 kg / mm ² by pressurizing the piston,
Cylinder and piston withstand pressure limit of about 5.6G each
Pa, about 6 GPa.

[0019]

Embodiment 3 The apparatus configuration shown in FIG. 3 was used. 170k tensile strength as the material of the cylinder body (large diameter cylindrical part)
g / mm ² Die steel having a compressive strength of 250 kg / mm ² was used, and as a material of the sleeve (small cylindrical portion), a tensile strength of 250 kg / mm ^{2 and a} compressive strength of 280 kg / mm ^{2 were used.}
High speed steel was used. 250 kg / mm on sleeve inner wall
² was press-fitted into the cylinder body so as to apply a preload, thereby producing a pressure-resistant container of about 5 GPa. At this time, a force of about 150 kg / mm ² was applied to the inner wall of the cylinder body. 300k of Pb-10% Zn alloy filled in the space in contact with the end face of this sleeve and the side face of the movable piston
By applying a force of g / mm ² , the withstand pressure limits of the cylinder and piston are about 5.7 GPa and about 6.6 G, respectively.
Pa.

[0020]

Embodiment 2 The apparatus configuration shown in FIG. 4 was used. The same material as described above was used for the sleeve (cylinder small-diameter cylindrical portion) and the large-diameter cylindrical portion (cylinder main body). A gap of 3 mm was provided between the sleeve and the cylinder body, and the gap was filled with lead. At the same time, the space in contact with the end face of the sleeve and the side face of the piston was filled with lead. 300k for this lead
By applying a force of g / mm ² , a cylinder of high-speed steel withstanding a pressure of about 7 GPa was obtained.

[0021]

As described above in detail, in the device of the present invention, the piston and the cylinder of the piston-cylinder type high-pressure and high-temperature device are formed in a step shape, and the small-diameter portion and the connection portion of the piston and the large-diameter cylinder of the cylinder are formed. An annular space surrounded by the wall surface of the cylindrical portion (cylinder body) and the end surface of the small-diameter cylindrical portion (sleeve) is filled with a plastic pressurizing medium. For this reason, when an ultrahigh pressure is generated by the advance of the piston, the Poisson effect caused by pressurization is canceled or the piston and the sleeve are reinforced by compression. Therefore, the service life of pistons and cylinders can be increased, and the size of the equipment can be increased. The piston-cylinder type ultra-high pressure and high temperature equipment can economically synthesize and grow diamond and cubic boron nitride. Manufacturing is now possible.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a typical example of a conventional apparatus configuration.

FIG. 2 is a longitudinal sectional view of a main part in an axial plane, showing an example of an ultrahigh-pressure high-temperature device configured according to the present invention.

FIG. 3 is a similar sectional view showing another example.

FIG. 4 is a similar sectional view showing still another example.

[Explanation of symbols]

 Reference Signs List 1 cylinder 2 fixed piston 3 compression ring 4 lower piston 5 sample 20 cylinder 21 cylinder body 22 sleeve 23 pressurized medium sleeve 24 fixed piston 25 movable piston 26 piston base 27 piston small-diameter cylindrical portion 28 reaction sample

Claims (9)

(57) [Claims] (1) For a piston-cylinder type ultra-high pressure high temperature device
, Made of high-rigidity material, discontinuous toward the tip
The movable piston, whose diameter is gradually reduced, is essentially (1) a large diameter
Cylindrical part (piston base) and (2) tip of piston base
An essentially cylindrical portion (No.
(1st stage piston) and (3) projecting from the end face of the 1st stage piston
And a smaller diameter essentially cylindrical section (second stage piston
(4) Connection between the piston base and the first stage piston
And (5) Connection connecting first stage piston and second stage piston
And similarly made of a highly rigid material,
The cylinder whose diameter is discontinuously reduced by (6)
Large diameter cylindrical part where the tongue base slides and (7) inward of diameter
The first stage piste protrudes from the large diameter cylindrical part toward
The first-stage small-diameter cylindrical part where the blade slides, and (8) inward of the diameter
Projecting from the first-stage small-diameter cylindrical part toward the second stage
The second-stage small-diameter cylindrical portion where the piston slides, and (9) large-diameter
A connecting portion connecting the cylindrical portion and the first-stage small-diameter cylindrical portion;
0) Connect the first-stage small-diameter cylindrical part and the second-stage small-diameter cylindrical part
(11) outer peripheral surface of the first stage piston, large diameter circle
Connect the inner peripheral surface of the cylindrical part, the piston base and the first stage piston.
Surface and large-diameter cylindrical part of the connecting part and first-stage small-diameter cylinder
Space surrounded by the surface of the connection that connects the
The outer peripheral surface of the second stage piston, the first stage small diameter cylindrical portion
Inner circumferential surface, connecting part connecting first stage piston and second stage piston
Surface and first stage small diameter cylindrical part and second stage small diameter cylindrical
Plastic space in the space surrounded by the surface of the connecting part
Consisting of inorganic or organic substances or their composites
Filling with pressurized medium
When pressure is generated, it occurs on the piston and cylinder
At least partially offset the Poisson effect
An ultra high pressure and high temperature device. 2. The pressurized medium is lead, tin, zinc, antimony, silver, gold, aluminum, indium, various alkali metals or an alloy containing these as a main component.
2. The ultra-high pressure and high temperature apparatus according to 1. 3. The pressurized medium is wax (wax), clay, talc, an alkali metal halide, silver chloride, h-BN,
The ultrahigh-pressure high-temperature device according to claim 1, wherein the ultrahigh-pressure high-temperature device is one or two or more inorganic mixtures selected from graphite. 4. The ultrahigh-pressure high-temperature apparatus according to claim 1, wherein the pressurized medium is one or more organic mixtures selected from vinyl, polyethylene, polypropylene, and Teflon. 5. The ultra-high pressure and high temperature apparatus according to claim 1, wherein the overhang portion is formed integrally with the cylinder body. 6. The ultrahigh-pressure high-temperature apparatus according to claim 1, wherein the overhang portion is formed as a sleeve-like body separated from the cylinder body, and is fitted to an inner peripheral surface of the cylinder body by applying a preload. 7. The ultra-high pressure and high temperature according to claim 1, wherein the overhang portion is formed as a sleeve-like body separated from the cylinder main body, and is fitted and press-fitted into the inner peripheral surface of the cylinder main body in conjunction with pressurization. apparatus. 8. The ultrahigh-pressure high-temperature apparatus according to claim 1, wherein a pressurized medium is arranged between the opposing peripheral surfaces of the cylinder body and the sleeve. 9. The ultrahigh-pressure high-temperature apparatus according to claim 1, wherein said high-rigidity material is at least one selected from cemented carbide, die steel, and high-speed steel.