JPS588891B2 - Atsushiyorihouhou Oyobi Souchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves increasing the pressure on the material to a predetermined pressure when pressurizing the material in a high-pressure chamber by using one or several pistons that act on the material throughout the pressurizing process. Intermediate, 1st
The present invention relates to a pressurization treatment method that uses pressure generating force to maintain a high pressure chamber at a desired level of pressure during the pressurization treatment.

The invention is particularly advantageous for use in the production of synthetic diamonds, but is not limited thereto.

The phase diagrams for carbon and for the structure of graphite and diamond are now well known in their entirety and have proven to be extremely useful for the production of synthetic diamonds, which now require extremely high pressures during the production process. It is possible to produce synthetic diamonds suitable for industrial use on the basis of graphite in the resulting high-pressure equipment.

Traditional high-pressure equipment configured for diamond production typically
It consists of an internal pressure chamber, a pressure absorption device surrounding the internal pressure chamber, and one or several (usually two) pressurizing pistons, which are movable in the direction toward the center of the internal pressure chamber. On the other hand, for the purpose of compressing the graphite body placed within the internal pressure chamber, the volume of the internal pressure chamber is reduced.

The pressure exerted by the pressure piston is not always transmitted directly to the graphite body, but can be transmitted through an elastic sealing material such as rubber or similar material.

Another common sealing material is pyrophyllite, which is an aluminum silicate material that can form a sealing medium when compacted into a gap.

The theory proposed by Messrs. Berman and Simon (Zeitschrift fur ml)
electrochemie magazine. 59. 1955 No. 355
It is theoretically possible to convert graphite to diamond by applying pressure and temperature to graphite within the diamond stability range of the carbon phase diagram.

Recent studies (e.g. by ASEA and General Electric) have established the existence of both diamond-stable regions and regions with stable carbon of non-diamond properties within the carbon phase region, extending previous findings by scientists. Contrary to the above, it has recently been found that the requirements necessary to convert carbon into diamond cannot be satisfied by mere adaptation or following of carbon with non-diamond properties to states of properties that fall within the diamond stability region of the phase diagram. It turned out that.

In order to meet all the requirements, Swedish Patent No. 2 granted to General Electric Company 1. 5 0
According to the specification of No. 13, it is stated that a catalyst must also be present.

This idea is supported by Japanese scientists.

(Swedish Patent No. 328856, Swedish Patent No. 33000
5, see specification No. 338,760), but General Electric subsequently abandoned this idea and the company now states that it is possible to produce hexagonal diamonds at high pressures and temperatures in the absence of a catalyst. (See Patent No. 333137).

The aforementioned Swedish Patent No. 333,137 suggests the introduction of graphite bodies into high pressure/high temperature devices, where the crystalline domains are relatively large and complete and the C-axis is aligned more dominantly in some directions than in others. , and thus the graphite is oriented in the device such that the C-axis orientation is approximately aligned with the action of pressure.

The material is exposed to a variable high pressure at least comparable to the pressure at the three-phase equilibrium point (the so-called three-phase coexistence point) between solid diamond, solid graphite and liquid carbon, and the temperature of the material is increased to at least 3
If the graphite body is returned to ambient pressure and temperature by raising the temperature to 000° C., hexagonal diamond is obtained in the graphite body.

Furthermore, as a result of intensive research on the carbon phase diagram, we found that there is one region where both graphite and metastable diamond can exist, one region where diamond and metastable graphite exist, one high temperature region where only graphite exists, and one region where diamond is the only region. It has now been confirmed that there are 1 high-pressure region in which carbon (diamond) exists, 1 higher-pressure region in which carbon (diamond) exists in metallic form, and 1 high-pressure/high-temperature region in which only a liquid phase exists.

In addition to research on carbon phase diagrams, we have developed a high-pressure device that greatly facilitates these studies.

These high pressure devices can be broadly classified into two types.

The first type of high-pressure device consists in principle of one hollow pressurized cylinder and two pressurized pistons, each of which consists of a number of cylinders forming a shrink-fitting band or band of continuous or partial copper rings. approximately surrounded by concentric parts.

The pressurizing piston is inserted from both ends of the pressurizing cylinder cavity into the cylinder chamber forming a high pressure chamber, and the reactant material (graphite in the case of producing synthetic diamonds) is placed in the high pressure chamber surrounded by a concentric cover of phyllite. center.

The entire device is placed in a hydraulic press, and the pressure pistons are pressed into the cylinder cavity opposite each other.

The contents at the center of the high pressure chamber are thus compressed;
A portion of phyllite is extruded into the space between the piston and cylinder.

Phylolite has the property that its internal friction increases considerably with increasing pressure.

Thus, the pyroliths displaced into said space create a resistance to further displacement and form a seal that allows further compression of the remainder of the contents in the high pressure chamber.

Electric current is used to increase the temperature, and if the reactant material is graphite, the current can be conducted directly through the reactant material.

The second type of device differs from the first type of device described above essentially in that it does not use a sealing member of phyllite or equivalent material.

A steel cylinder containing two chambers with different dimensions is placed in the center of the device, with the smaller dimension being the high pressure chamber and the larger dimension being the hydrostatic support pressure for the pressurizing piston that is pushed into the high pressure chamber. In addition, the structure is arranged to compress the contents of the high pressure chamber.

A plurality of conical pistons are arranged around the cylinder, each piston fitting into a respective one of a plurality of conical holes formed in the outer cylinder.

Pressure is obtained by forcing a piston (generally six) into each conical hole in the outer cylinder with a block covering the inner cylinder.

The inner cylinder containing the high pressure chamber is compressed radially and axially.

The material to be treated is compressed in a high-pressure chamber, and the required heating takes place via electric low resistance elements or directly by electric heating.

A common feature of all these known methods and devices is that the pressure applied to the reaction material must reach a certain value at a certain temperature, and the reaction material must be maintained at this pressure and at this temperature for a fairly long period of time. There is.

Since the minimum pressure is determined by the chosen operating temperature and it is necessary to maintain a relatively high temperature in order to achieve the phase transformation within the desired time, it is also necessary to use a correspondingly high pressure.

However, the effect of volume reduction on the reacting materials during the phase transformation to diamond is ignored, and this is achieved by using pressures high enough to keep the equilibrium line of the phase diagram to the right (upper side) under all circumstances. This seems to be due to the fact that it is considered possible.

Although in such embodiments the risk of sub-critical pressures at the main temperature once the reaction (phase transformation) is started is removed, the resulting product is necessarily poor in quality and unnecessarily The present invention aims to obviate this drawback and achieves this object, which necessitates the use of equipment with a large pressure capacity, resulting in an unnecessarily large energy consumption in order to generate the required pressure. To achieve this, the present invention increases the pressure on the material to a predetermined pressure during pressurization of the material in a high-pressure chamber, and increases the pressure on the material through one or several pistons acting on the material throughout the pressurization process. A method for pressurizing a material by means of a first pressure-generating force, in which at least a limited volume of a liquid medium under an applied maximum pressure is passed through a high pressure chamber and around one or more pistons into said first pressure-generating force. compressing via a second pressure generating force to a pressure selected lower than the pressure generating force, and a pressure selected lower than the first pressure generating force in the high pressure chamber created a tendency to change this; In this case, the pressure selected to be lower than the first pressure generating force is maintained at a predetermined value.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As can be seen from the foregoing, the conversion of graphite to diamond can be facilitated when appropriate catalysts are used.

Several catalysts have been described for this purpose in patent specifications (e.g. Swedish Patent Specification No. 215013, Swedish Patent Specification No.
No. 5, No. 339459 and No. 328856,
Same No. 330004, Same No. 330005, Same No. 338
No. 766).

The pressure/temperature diagram in Figure 1 is from Berman and Simon.
Figure 2 shows part of the curve extrapolated by him, the so-called phase curve, associated with two-carbon phase graphite and diamond.

The upper region of the curve represents the diamond stability region, the lower region of the curve represents the graphite stability region, but in between these regions exist the metastable region for diamond and metastable graphite and for graphite and metastable diamond (e.g. , the above-mentioned patent specification or “Kosmos”19
A paper in 1965 “Synthetic Diam”
(See the carbon phase diagram described in "Onds").

The exact research and importance of this area has not been fully explored, but in principle it does not affect the present invention.

As previously mentioned, it is possible to further transform diamond by simply maintaining it within the diamond stability region, i.e. at least within the easily achievable pressure and temperature range, at pressures and temperatures above the critical pressure and temperature defined by the phase curve. Otherwise, it is believed that graphite and other carbonaceous materials can be maintained at the above pressures and temperatures for an indefinite period of time without undergoing any transformation.

Conversion to such diamonds is facilitated by the use of catalysts, together with pressure and temperature conditions suitable for such catalysts, but in FIG. Ru.

Generally, different curves are obtained for other catalysts such as nickel, for example the Ni curve for nickel lies above the Fe curve.

In Fig. 1, curve 1 is the phase boundary line between the diamond stable region and graphite stable region, and curve 2 is the phase boundary line between the diamond stable region and graphite stable region, and the curve 2 is the phase boundary line between the diamond stable region and the graphite stable region.
Curve 3 shows the lower limit of the region where nickel (Ni) acts as a catalyst, and dashed lines 4p and 4t indicate the optimum results when using iron as a catalyst. The dashed lines 5p and 5t respectively show the pressures and temperatures required to obtain optimum results when using nickel as a catalyst.

When producing diamond from graphite in the conversion region for the Fe curve (and the Ni curve and sometimes other catalyst curves), the diamond is stable within the pressure and temperature ranges established with at least some certainty by conventional equipment. It has been discovered that as the pressure and temperature increase within a region, the quality decreases.

This paradoxical phenomenon is explained by the fact that as the conversion temperature increases with pressure and temperature, the direct formation of microscopic diamond crystals probably occurs at every point on the graphite, with microscopic This is thought to be caused by agglomeration of diamond crystals.

Within the first part of the triangular curve defined by the catalyst, i.e. Fe
Operating as close as possible to the corners of the triangle in the curve results in a slower conversion to diamond and a crystal growth that is superior in quality to the initially formed diamond crystal.

With modern devices for generating high pressures and high temperatures at the same time, it is possible to maintain a given pressure at a constant temperature for only a very short time.

It is difficult to control phase conversion at such high pressures and temperatures.

For example, when producing industrial diamonds by known methods, it is not possible to adequately compensate for the volume reduction caused by diamond formation and growth.

FIG. 2 shows a highly simplified phase diagram for graphite/tire metal, in which the region above straight line a, the equilibrium line, represents the diamond stable phase, and the region below straight line a represents the graphite stable phase.

Straight line b is determined by the type of catalyst used.

The shaded area can be divided into three areas as shown in FIG. 2, and these areas are not clearly or strictly defined.

These areas are oriented in the direction of point X.

In region (3) rapidly growing crystals are formed.

The number of crystals and their growth rate increase with increasing pressure and temperature, but in region I, where the quality of the crystals is correspondingly poor, fewer crystals are formed and the growth rate is slow.

In region H, conditions are much more favorable than in region (I), and as point X is approached it is possible to grow larger single crystals and operate to further increase the strength and quality of the diamond.

Now operating along the straight line OABC, i.e. the pressure is rapidly increased to A and energy is applied to the body of reactant material,
Increase temperature to B under constant pressure.

The temperature at this point is high enough to initiate diamond formation and growth, and at point C, where the pressure drops to C, diamond growth stops and the process is interrupted.

In the high-pressure processing apparatus according to the present invention, the pressure and temperature can be adjusted to follow any predetermined curve, for example the dashed line ODE.

In this case the pressure increases first to D and then along the ascending dashed line to E or some other predetermined point in the phase diagram.

Diamond is formed and grown at E while reaching a preset pressure that can be maintained or adjusted as a function of time.

Therefore, it is possible to control the process over a much longer period of time, resulting in favorable diamond grain growth and diamond grains of desired grain size and quality.

Diamond grains suitable for polishing are formed in a few seconds; formation of diamond grains on a grinding wheel takes more than a minute, and diamond grain growth is controlled for use in rock drill type tools. In some cases, it usually takes quite a long time.

In addition to the ability to adjust pressure/temperature and maintain them constant, there is the added benefit of being able to select pressure and temperature increases that are not significantly different from those mentioned above for the press members, sealing members, gaskets, etc. of the pressure treatment equipment. There are advantages.

FIG. 3 shows the basic structure of a pressure treatment apparatus for carrying out the method of the present invention, and its functions will be explained below.

As mentioned above, during the phase transformation to diamond, which has a much higher density than graphite (the density for diamond is 3.5 to 3.53, the density for graphite is about 2.1 to 2.2). ) It has proven difficult to maintain within the optimum part of the Fe curve (or any other predetermined part of the diamond stability region), especially due to changes in the volume of the reacting material body.

When operating at a pressure and temperature very close to the corner of the Fe curve, i.e. at the optimum point, the phase transformation to diamond and the resulting reduction in the volume of the reacting material body results in a pressure reduction, which is The pressure drop is sufficient to drop below the diamond stability region where no conversion occurs.

On the other hand, if one chooses to operate at a point high enough so that changes in volume do not cause the pressure to drop below the diamond stability region, in order to ensure in case this is not achieved, then for the reasons mentioned above, much less and Diamond crystals of poor quality result.

In the present invention, this problem is solved in the reaction chamber as the pressure and temperature in the reaction chamber correspondingly increase due to the change in volume of the reactant body to an optimum point selected for the pressure and temperature region within the operating range. Correcting pressure is generated in the manner described below for the production of synthetic diamond by the pressure treatment apparatus of the present invention, which is exemplified in FIGS. 3 to 6. Do it through.

It should be noted that the mode of operation and the device according to the invention can of course also be used for processing other materials if it is desired to maintain a constant pressure in a high-pressure installation.

The device according to the invention shown in FIG. 3 comprises, in a manner known per se, a pressurizing cylinder 1 with a central reaction chamber 2 and two punches or pressurizing pistons 3, which are connected via a high-pressure press 4 to the reaction chamber. High pressure can be applied to the reaction material body 5 placed in the reaction chamber 2 by inserting it from both ends of the reaction material body 2 .

The cylinder 1 is made of steel or other material such as a ceramic material, for example boron carbide (conductive) or aluminum oxide (non-conductive), and is surrounded by a strip consisting of three cylindrical concentric steel jackets; The hardness of these jackets increases inwardly and the ductility increases outwardly.

Therefore, the inner jacket 6 has the greatest hardness and the outer jacket 8 has the greatest ductility.

In the embodiment of the device according to the invention shown in FIG. 3, the pressurized cylinder 1 abuts the inner jacket 6 over a limited area of its outer periphery.

This region may be constituted by a relatively small annular support surface 9 extending radially inwardly at the center of the inner circumferential edge of the inner jacket 6 .

On one side of the annular support surface 9, the outer circumferential surface of the pressure cylinder defines a gap 10 with respect to the inner jacket 6.

Each gap 10 communicates with an annular chamber 11 formed between the piston 3 and the inner jacket 6, and between the corresponding end of the pressure cylinder 1 and the piston part 12, respectively.

The two gaps 10 and the two annular chambers 11 are completely filled with a liquid-permissive fluid medium, such as oil.

This medium forms the supporting pressure medium for the pressurized cylinder 1 and the piston.

The body 5 of reaction material in the pressurized chamber 2 may be surrounded by a sealing material 13, such as pyrophyllite.

The invention requires the use of a liquid, in particular oil, as supporting pressure medium in the gap 10 and the annular chamber 11;
This supporting pressure medium is used for specific purposes of the present invention, as explained below.

An annular space 10 on both sides of the pressurized cylinder 1
, 11 are connected to valve 15 via channel 14, and valve 1
Although 5 illustrates a spring-actuated return valve to simplify the drawing, valve 15 can be precisely adjusted and set to a desired opening pressure in the direction shown in FIG. 3 and satisfies the objectives described below. Of course, it is necessary to construct the valve with a valve that

The purpose of the piston 12 is to remove oil (
or other suitable supporting pressure medium), and at the same time the piston 3 is forced into the reaction chamber 2 and applies pressure to the body 5 of reaction material.

In the illustrated embodiment, the portion 16 of the pressure piston 3 to be pressurized into the pressure cylinder 1 is made of a hard metal, such as tungsten carbide, and the piston 12 for pressurizing the oil is made of a hard metal such as tungsten carbide.
are two steel rings 17.1 attached to the pressure piston 3.
Consists of 8.

Of these rings, the rear ring 18 is rested relative to the press 4, while the front ring 17 has a shape adapted to a cavity in the inner jacket 6, into which this ring 17 is inserted. , and this cavity is sealed to the inner jacket 6 via one or several hydraulic sealing rings 19 .

Therefore, if the two piston parts 16.17 of the piston unit 3.12 are pressed into the associated cylinder chamber, the reaction material body 5 and the pyrophyllite seal 13 as well as the space 1
Since the oil in 1, 12 is compressed, it supports the pressurized cylinder 1 and acts to eliminate the bursting strength acting on the cylinder 1 and piston 3 due to its pressure.

The diagram in FIG. 8 shows the volume change process (
(Illustrated in simplified form in the diagram in Figure T)
The inventive method for ensuring a pressure drop as a result of is illustrated in a somewhat simplified manner.

Figure 7 shows the point P1 where the volume of the reaction material corresponds to the original volume.
The graphite 5 in the reaction chamber 2 rapidly decreases from the point P2 to the point P2 in connection with the application of pressure at which the phase transformation to diamond begins.

Thereafter, the volume of the reacting material decreases along a gently sloped curve (here shown as a curve) to point P3, where the phase transformation ceases and the pressure decreases, so that the volume of the material increases again, but It does not increase enough to restore its original volume.

In FIG. 8, curve A shows how the pressure in the reaction chamber 2 increases from P1 to P2 along a steeply rising curve section, in which case the pressure remains constant at point P3 where the phase transformation ends and the pressure decreases. will be maintained.

Curve B shows the oil pressure over the same period of time.

From point P1, the oil pressure must be increased to point Po2 and then kept constant until point Po3, at which point the entire phase transformation process ends.

The volume of oil is chosen appropriately so that the pressure at point Po3 approximately corresponds to the maximum compression of the oil.

This pressure can be, for example, 25 kbar (
(in addition to supporting pressure on the piston and pressurized cylinder)
, forming a compensation pressure which acts as a counterforce on the piston unit 3.12.

If this pressure is exceeded, valve 15 allows oil to be drained approximately exactly as much as is necessary to maintain the oil pressure at a predetermined level (in this case 25 kilobar).

In the diagram of FIG. 8, points P2 and Po2 must be reached at the same time as a whole; this is possible by correct adjustment or selection of the oil volume.

If the volume of the reaction material decreases along the curve A from point P2 to P3, the back pressure on the pressurizing piston decreases, so that if a constant pressure is applied to the piston units 3, 12 via the press 4, the piston from the press 4 The increased pressure is transmitted via 12.

If the oil pressure attempts to increase above the maximum oil pressure set via the valve 15, the valve 15 releases the oil and the piston unit 3.12 moves inward by a corresponding degree to reduce the oil volume. This means that the piston maintains the pressure in the reaction chamber 2 at a substantially constant level.

Instead of the need to precisely adjust the volume of oil in the oil space from the beginning of the pressurization process, for example, one pressure increase phase between points P1 and P2 in the diagram of FIG. It is possible to drain the oil via a pair of oil charging valves 20 connected to the pump 21 and to reach points P2 and Po2 simultaneously.

In the apparatus according to the embodiment of the present invention shown in FIG. 17.18 individual steel rings
Or, it consists of a single ring.

Via the main piston 3 or an electrical wire connected to the main piston 3 and shown in broken lines, a current is passed from the connection 24 to the reaction material body 5 to effect direct electrical heating of the reaction material body 5, in which case the reaction material is graphite or In cases where other conductive materials are used and the reactive material is required to be non-conductive, indirect heating is used.

In the present invention, the aim is to achieve relatively long-term reactions (seconds, minutes, hours or weeks), in which case a conventional current source, for example a three-phase alternating current with a power of 100 kW at 40 V, is used. A generator can be used.

If sometimes a short heating step is desired, other current sources can be used, for example the discharge of a large capacitor.

It is important that the volume of the oil does not change when the temperature changes, and for this purpose the shrink fit 6, 7, 8, in particular its inner jacket 6, is preferably cooled by a cooling medium, especially in the oil area. Arrange configuration.

For this purpose, the pressure treatment device is provided with suitable passages for water cooling, and these cooling passages are suitably configured and arranged to weaken the material of the inner jacket 6 as much as possible and at the same time to achieve the most effective cooling. Make it familiar.

The illustrated water cooling system is provided with a number (four) of cooling water supply and drain pipes 24', the ends of which project into a support ring 25 resting on the intermediate jacket 7; multiple radial communication channels 26 formed in the
and forming an axially extending receiving and distribution channel 27 between the inner jacket 6, the intermediate jacket 7 and the support ring 25; A number of parallel cooling channels 28 extend around the outer circumferential surface.

This arrangement makes it possible to maintain the walls around the oil and the oil itself at a constant temperature of about 60 DEG C., without significantly weakening the material of the strips 6 to 8, in particular of the inner jacket 6.

FIG. 6 shows the annular support surface 9 on the inside of the inner jacket 6 as a conductive bridge for carrying the current (current path indicated at 29) used to heat the body of reaction material to the desired temperature range. To give an example of the form that can be used, when producing synthetic diamond in the optimum region of the curve Fe in the diagram of Fig. 1, this temperature range is 1500°C.
Located nearby.

However, the annular support surface 9 need not be continuous in shape, but can be cut through an axial oil passage channel extending between the two pressurized oil sections on either side of the pressure chamber.

The present invention is not limited to the production of diamonds, but may be applied to other materials other than carbonaceous materials during testing or processing steps where it is desired to maintain the pressure at a predetermined value irrespective of a reduction in the volume of the material being processed. For example, the apparatus of the present invention can be used for the production of isotropic boron nitride crystals.

The device of the present invention also uses a tracer element (such as boron or aluminum) in the diamond crystal lattice:
(see No. 1) can be used in the production of semiconductor diamond crystals, especially when using graphite or other carbon as the starting material, with careful pressure applied during the process. Must be maintained at a predetermined value.

Furthermore, the apparatus of the present invention can be used to study the quality of diamonds and other materials when they are exposed to high and substantially constant pressure for long or short periods of time.

The present invention is not limited to the apparatus described in detail above, but also includes apparatuses with various modifications to achieve the desired objectives.

For example, a support in the annular space 10.11 to make it possible to keep the pressure in the reaction chamber 2 approximately constant (or to make it possible to increase the pressure in the reaction chamber 2) during the phase transformation of the material to be treated. The reduction in pressure can be achieved in other ways than through the evacuation of pressurized fluid from the annular space 10.11.

Such pressure reduction can be achieved by reducing the amount of pressure applied to the pressurized fluid.

Therefore, the apparatuses described above are only preferred embodiments for use in carrying out the method of the invention, and the method of the invention can also be carried out with various apparatuses other than the embodiments described above.

The use of a support pressure medium as pressure compensation medium, as mentioned above, is suitable if the pressurized cylinder and also the piston are considered to require hydraulic support, in which case the piston and/or the support pressure medium used is By appropriately adjusting the volume of the supporting pressure medium and/or the inner and outer circumferential surfaces of the pressurized cylinder to each other, the supporting pressure (25 kbar in the case of FIG. 8) acting on the outer circumferential surface of the pressurized cylinder is applied to the pressurized cylinder. In this case, the value of bursting strength becomes zero.

And this value can even be negative.

Furthermore, in a supporting pressure medium, said support surface 9 for a pressure cylinder arranged in a floating manner can be suitably arranged on the pressure cylinder or in some cases omitted.

The device described above with reference to the drawings uses the same press both for pressing the piston 3 into the high-pressure chamber 2 for compression and for pressing the steel ring 17 against the space 11 for compressing the pressure compensation medium.

However, the invention also encompasses a device of the type in which the required pressure is applied to the piston 3 (or pistons 3) and the steel ring 17 (or steel rings 17) by means of two separate actuating devices.

The pressure acting on the steel ring 17 can be adjusted in such a way that said pressure maintains the ring 17 in a depressed position during the entire processing process in order to achieve the desired maximum pressure.

The pressure acting on the piston 3 can be suitably regulated, and at the moment of phase change of the material to be treated (if a volume reduction occurs in the high pressure chamber) an additional pressure is supplied to said pressure for the treatment. The pressure is adjusted to be maintained at a predetermined value near the upper side of the phase diagram phase curve associated with the particular material being processed in the high pressure chamber.

Additionally, this pressure can be achieved through means of sensing the state of the process pressure or a decreasing trend in the process pressure.

This type of device therefore does not require a pressure equalization device for the pressure compensation medium.

In some types of equipment, for example those where it is not necessary to use supporting pressure, space for a pressure compensation medium (can be oil, but also other media that are liquids that can be used at the relevant operating pressures); The device cooperating with the press or the pressure piston for compressing the pressure compensation medium can also be constructed and arranged in other ways convenient and suitable for the device.

The invention relates to the growth (in terms of speed and dimensions) of crystal structures.
gives the possibility to control.

Additionally, the present invention allows individual crystals to be grown to substantial dimensions.

This was made possible by keeping the pressure of the reactants constant throughout, despite the volume reduction of the reactants occurring during the phase transition.

Example The pressure and temperature used were the values obtained from Figures 1, 2 and 8, i.e. an oil pressure of 25 Kbar and a reactant pressure of 55 Kbar, and a temperature of the reactants of approximately 1500°C, an efficiency of 100 kW and a voltage of 40 V. Obtained by Sanwa Generator with

In the test plant, 100 g of graphite was used and an alloy based on iron and nickel was used as the catalyst.

After processing for several minutes (5 to 10 minutes), diamonds of a quality suitable for use in abrasive wheels etc. were obtained.
After processing for 0.5 to 1 hour, the diamond was of stone cutting quality, and after processing for several hours, tool quality diamond was obtained.

A preferred embodiment of the method of the present invention is as follows.

(1) During pressure treatment of the material in a high pressure chamber, the pressure on the material is increased to a predetermined pressure, and the increase in the pressure on the material is applied to the first piston through one or several pistons that act on the material throughout the pressure treatment. A method for the pressure treatment of materials by means of a pressure-generating force, in which at least a limited volume of the medium in liquid form is moved under an applied maximum pressure into a high-pressure chamber and around one or more pistons, said first pressure-generating compressing via a second pressure generating force to a pressure selected to be lower than the force;
A method for pressurizing a material, characterized in that the selected pressure in the pressure chamber is maintained at a predetermined value when there is a tendency to change the selected pressure.

(2) In the pressurized treatment method according to the above item 1, the pressure of the medium acting as a pressure correction medium is reacted to the pressurizing phase of the working pressure through a force that generates the pressure in the high pressure chamber. the selected pressure at is maintained at a predetermined value close to the upper side of the phase curve of the phase diagram associated with the material by reducing the counterpressure of the pressure compensation medium when there is a tendency to change it; The two pressure-generating forces are correlated, and the pressure of the pressure compensation medium is varied proportionally to reflect the tendency to change the pressure on the material in the pressure chamber, and the pressure adjustment results in two selected A pressure treatment method characterized by maintaining the pressure at a predetermined value.

(3) In the pressure treatment method according to item 2 above, when the material is treated at a predetermined maximum pressure at which the volume of the material decreases as a result of the reaction or phase transformation process, the reduction in the volume of the medium is controlled. A pressure processing method characterized by increasing the applied force using a pressure generating force to maintain the pressure at a predetermined value close to the upper side of the phase curve of the phase diagram of the material despite the volume reduction of the material.

(4) Graphite or other carbonaceous material is treated at high pressure and high temperature in a high pressure chamber to produce diamond crystals in the presence of a catalyst, the catalyst according to the graphite/diamond phase diagram (e.g., FIG. 1 or A generally triangular diamond-forming region is defined within the diamond stability region (according to FIG. In the pressure treatment method according to item 1 above, the volume of the pressure correction medium is selected to be a point located at the lowest corner of the diamond forming region in terms of pressure and temperature, relatively close to the boundary of the Fe curve in the figure. A method of pressurization, characterized in that the volume reduction of the carbon material resulting from its formation is substantially proportional to the volume reduction, thereby establishing and maintaining an operating point for the pressure while maintaining an optimum pressure for the temperature in question.

(5) When processing materials under pressure in a pressure chamber, movable pressure generation that applies pressure to the material in the pressure chamber through one or several pistons through the reduction of the pressure chamber volume in addition to the pressure chamber; An apparatus for pressurized treatment of materials for carrying out the method according to paragraph 1 above, comprising at least one closed space for holding a limited volume of liquid pressure compensation medium at high pressure. a second movable pressure generator configured and arranged to supply pressure to the pressure compensation medium outside the pressure chamber and one or more pistons; An apparatus for pressurizing a material, characterized in that it is configured and arranged to maintain a certain value.

(6) In the pressure treatment apparatus according to item 5, which implements the method described in item 2 above, a pressure limiting device that is adjustable in the space for the pressure correction medium is connected, and two pressure restriction devices are connected to the pressure treatment apparatus. a device for interconnecting the two pressure generating devices so that said two pressure generating devices can be moved in unison so that any force acting on said one pressure generating device also acts on said other pressure generating device; said pressure limiting device by increasing the force acting on said one of said pressure generating devices after said interconnection device is properly configured and the maximum pressure set by said pressure limiting device is reached; The volume of said pressure compensation medium is reduced through the device, so that both the maximum pressure of the pressure compensation medium and the maximum pressure in the pressure chamber are maintained at predetermined values, and the pressure in the pressure chamber is brought above the phase curve of the phase diagram for the material in question. and a corresponding decrease in the volume of the material in the pressure chamber.
1. An apparatus for pressurized processing of materials, characterized in that the pressure on the pressure generator is increased to maintain both the pressure of the pressure correction medium and the pressure within the pressure chamber at predetermined values.

(7) The pressure chamber is constituted by a cavity formed in a high-pressure cylinder with both ends open, and the pressure generating device is provided with two pistons that can be tightly introduced into the both ends, and the high-pressure cylinder and the piston are connected to the piston. and a pressure treatment device according to claim 6, wherein the pressure generating device is also provided with two annular pistons, each annular piston being one of the first pistons in the plurality of first pistons. are respectively arranged on one piston of
extending proximately within each annular cylindrical end of said annular space and connected to said first piston or to an actuation device common to all of said pistons, said pressure limiting device being connected to said annular space; An apparatus for pressurized processing of materials, characterized in that the supporting pressure medium forms the pressure correction medium.

[Brief explanation of the drawing]

FIG. 1 is a state diagram for explaining the method of the present invention, FIG. 2 is another state diagram for explaining the method of the present invention, FIG. 3 is a longitudinal sectional view showing an embodiment of the apparatus of the present invention, and FIG. The figure is IV of Figure 3.
- VI line cross-sectional view, Figure 5 is the ■-V line cross-sectional view of Figure 4,
Figure 6 is an enlarged sectional view of the main part of Figure 3, Figures 7 and 8.
The figure is an explanatory diagram of the operation of the present invention. 1... Cylinder, 2... Central reaction chamber,
3... Pressure piston, 4... High pressure press, 5... Reaction material body, 6, 7, 8...
・Jacket, 9... Annular support surface, 10...
... Gap, 11... Annular chamber, 12...
・Piston part, 13...Sealing material, 14...
...Channel, 15...Valve, 16...
・・・Part, 17.18...Steel ring, 19...
......Hole pressure sealing ring, 20...Oil charging valve,
21...Pump, 22...Insulating material,
24... Connection, 24'... Tube, 25.
... Support ring, 27 ... Distribution channel, 28 ... Parallel cooling channel, 29 ...
...Current path.

Claims (1)

[Claims] 1. During pressurization of the material in a high pressure chamber, the pressure on the material is increased to a predetermined pressure, and the increase in the pressure on the material is caused to generate a first pressure through one or several pistons that act on the material throughout the pressurization process. A method for the pressure treatment of materials by means of force, in which at least a limited volume of the medium in liquid form under an applied maximum pressure is caused by said first pressure-generating force around a high pressure chamber and one or more pistons. The first pressure is compressed via a second pressure generating force to a pressure selected to be lower than the first pressure generating force in the high pressure chamber, and when the pressure selected lower than the first pressure generating force in the high pressure chamber tends to change. A method for pressurizing a material, characterized in that a pressure selected to be lower than a pressure generating force is maintained at a predetermined value.