JPH10101434A - Production of polycrystal type cubic boron nitride and apparatus for generating high temperature and pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably produce a polycrystal type cubic boron nitride having high strength and high toughness in large amounts. SOLUTION: This method for producing a polycrystal type cubic boron nitride comprises arranging a cylindrical body 1 through gaskets 11 and 12 between a pair of anvil bodies 2 to form a central space part and successively installing an electrode plate 6, a pressure increasing plate 5 and a metal plate 3 on anvil body side of the central space part and installing a pressure medium 7 on the cylindrical body side to form a reaction chamber and charging a graphite cylinder 8 in which cBN raw material 10 is packed into a reaction chamber of a high temperature and high pressure-generating apparatus and retaining the raw material under thermodynamically stable conditions of cBN. In this case, a ratio (P1/P) of power (P1) expressed by product of anvil top area and generated pressure to power (P) used is kept to <=0.40 under >=7GPa pressure. This high-temperature and high-pressure-generating apparatus is applied to the method for producing the compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to cubic boron nitride (cBN), which has been used for grinding tools and cutting tools in recent years.
In particular, the present invention relates to a method for producing polycrystalline cBN having high toughness and a high-temperature and high-pressure generator applicable to the method.

[0002]

2. Description of the Related Art Conventionally, cBN has been produced by converting low-pressure phase BN such as hexagonal BN (hBN) into nitrides and borides of various metal elements.
Using boron nitride or the like as a catalyst, under conditions of thermodynamic stability of cBN, for example, a pressure of 5 to 6 GPa, a temperature of 1400 ° C. to 160
It has been synthesized by a catalytic method of holding at 0 ° C. or a direct conversion method of holding at a higher pressure and a higher temperature than the above conditions without using a catalyst. In particular, in the latter, by using pyrolytic BN (P-BN), which is a highly oriented hBN, as the hBN raw material, a pressure and temperature lower than the conventional one, for example, 7 GPa
Above, cBN can be synthesized at about 1800 ° C. or more,
Further, the obtained cBN is a polycrystalline body composed of fine particles, and is known to have excellent mechanical properties.
It is expected to be used as a higher performance tool material.

[0003]

However, when synthesizing such polycrystalline cBN, a high pressure of 7 GPa or more must be generated.
Pressure sealing makes it difficult to blow out the internal pressure, called blowout, to the outside, the graphite cylinder (reaction chamber) to crack, and to be unable to heat, and further, the pressure drop due to the volume shrinkage accompanying the conversion from hBN to cBN. There was a problem that the conversion was stopped and it was not possible to synthesize cBN in a larger amount.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above problems and to stably produce a large amount of high-performance polycrystalline cBN. The problem of cylinder cracking can be prevented by selecting the appropriate shape and dimensions and optimizing the amount of force applied. The problem of pressure drop generated during conversion to cBN can be prevented during heating. The present invention has been completed by finding that the problem can be solved by appropriately increasing the power and maintaining the pressure at or above a certain level.

That is, the present invention provides the following.

[Claim 1] A cylinder body (1) is disposed between a pair of anvil bodies (2) via gaskets (11) and (12) to form a central space, and the central space is formed. An electrode plate (6), an intensifier plate (5) and a metal plate (3) are sequentially installed on the anvil body side, and a pressure medium (7) is installed on the cylinder body side to form a reaction chamber. The cBN raw material (1
In the method of charging the filled graphite cylinder (8) of (0) and holding the same under the thermodynamically stable condition of cBN, the amount of force (P) is expressed as the product of the area of the anvil tip and the generated pressure (P). A method for producing polycrystalline cubic boron nitride, wherein the ratio (P1 / P) to P1) is 0.40 or less under a pressure of 7 GPa or more.

[Claim 2] The method according to claim 1, wherein the high-temperature and high-pressure generator is of a flat belt type.

[Claim 3] A cylinder body (1) is arranged between a pair of anvil bodies (2) via gaskets (11) and (12) to form a central space, and the central space is formed. An electrode plate (6), an intensifier plate (5) and a metal plate (3) are sequentially installed on the anvil body side, and a pressure medium (7) is installed on the cylinder body side to form a reaction chamber. The cBN raw material (1
0) The method of loading the filled graphite cylinder (8) and maintaining the same under the thermodynamically stable condition of cBN, wherein the method is carried out under the following conditions (a) to (d). A method for producing a cubic boron nitride. (A) The ratio (H1 / φ3) of the height (H1) of the reaction chamber to the inner diameter (φ3) of the cylinder body is 0.48 or more and 0.68 or less. (B) The height (H1) of the reaction chamber relative to the height (H1) of the reaction chamber
1) and the sum of the thicknesses of the electrode plate, the booster plate and the metal plate (H
2) The ratio (H2 / H1) is 1.6 or more and 2.3 or less. (C) The ratio (φ2 / φ3) of the outer diameter (φ2) of the pressure medium to the inner diameter (φ3) of the cylinder body is 0.82 or more and 0.8
6 or less. (D) The height (H3) of the contact portion between the gasket (11) and the gasket (12) is (H2 / 2) -14 × φ3 / 50.
Above, (H2 / 2) −12 × φ3 / 50 or less.

(4) The method according to (3), wherein the high-temperature and high-pressure generator is of a flat belt type.

[Claim 5] The thermodynamic stability condition of cBN is such that the ratio (P1 / P) of the force (P1) represented by the product of the area of the tip of the anvil and the generated pressure to the working force (P) is 0. 4. The method according to claim 3, wherein the value is .40 or less.

[Claim 6] Inner diameter of cylinder body (φ3)
4. The method according to claim 3, wherein the ratio (φ1 / φ3) of the outer diameter (φ1) of the reaction chamber made of the graphite cylinder to 0.6 is 0.68 or less.

[7] The method according to any one of [1] to [6], wherein the power is increased while the cBN is maintained under thermodynamically stable conditions.

[8] The method according to [7], wherein the cBN raw material (10) is a pyrolytic boron nitride plate having a density of 2.05 g / cm ³ or more.

[9] The method according to claim 7, wherein the electrode plate (6) is made of molybdenum, the booster plate (5) is made of zirconia, and the metal plate (3) is made of stainless steel.

10. The method according to claim 7, wherein the gasket (11) is a pyrophyllite gasket and the gasket (12) is a paper gasket.

[Claim 11] When the pressure medium (7) is 5 to 3
The method according to claim 7, characterized in that the molded article is a hollow cylindrical molded article having a relative density of 92% or more containing sodium chloride containing 0% by weight of zirconia powder as a component.

[Claim 12] The zirconia intensifier plate is
The following (1) is composed of cubic and / or tetragonal and monoclinic.
The method according to claim 7, wherein the Xm value calculated by the equation is 0.3 or less (including 0).

(Equation 3)

[Claim 13] A pair of anvil bodies (2)
The cylinder body (1) is arranged via gaskets (11) and (12) to form a central space, and an electrode plate (6) and a pressure booster (5) are provided on the anvil body side of the central space. )
And a metal plate (3) are sequentially installed, a pressure medium (7) is installed on the cylinder body side to form a reaction chamber, and a graphite cylinder (8) is loaded in the reaction chamber. A high-temperature and high-pressure generator characterized by adding the following conditions (a) to (d). (A) The ratio (H1 / φ3) of the height (H1) of the reaction chamber to the inner diameter (φ3) of the cylinder body is 0.48 or more and 0.68 or less. (B) The height (H1) of the reaction chamber relative to the height (H1) of the reaction chamber
1) and the sum of the thicknesses of the electrode plate, the booster plate and the metal plate (H
2) The ratio (H2 / H1) is 1.6 or more and 2.3 or less. (C) The ratio (φ2 / φ3) of the outer diameter (φ2) of the pressure medium to the inner diameter (φ3) of the cylinder body is 0.82 or more and 0.8
6 or less. (D) The height (H3) of the contact portion between the gasket (11) and the gasket (12) is (H2 / 2) -14 × φ3 / 50.
Above, (H2 / 2) −12 × φ3 / 50 or less.

[14] The apparatus according to the above [13], wherein the high-temperature and high-pressure generator is of a flat belt type.

[Claim 15] The inner diameter of the cylinder body (φ
The apparatus according to claim 13 or 14, wherein the ratio (φ1 / φ3) of the outer diameter (φ1) of the reaction chamber comprising the graphite cylinder to 3) is 0.68 or less.

[Claim 16] The electrode plate (6) is made of molybdenum, the booster plate (5) is made of zirconia, the metal plate (3) is made of stainless steel, the gasket (11) is a pyrophyllite gasket, and the gasket (12) is Apparatus according to claim 13 or 14, wherein the apparatus is a paper gasket.

[Claim 17] When the pressure medium (7) is 5 to 3
The apparatus according to claim 13 or 14, wherein the apparatus is a hollow cylindrical molded body having a relative density of 92% or more containing sodium chloride containing 0% by weight of zirconia powder as a component.

[Claim 18] The zirconia intensifier plate is
(1) consisting of cubic and / or tetragonal and monoclinic
15. The apparatus according to 13 or 14, wherein the Xm value calculated by the equation is 0.3 or less (including 0).

Hereinafter, the present invention will be described in more detail.

The basic structure of the high-temperature and high-pressure generator used in the present invention is a flat belt type (for example, Japanese Patent Publication No. 59-55).
No. 47 gazette) and a girdle type (for example, JP-A-61-215).
293), but a flat belt type is preferable.

FIG. 1 shows an example of a schematic sectional view of a cBN synthesizing apparatus using a flat belt type high-temperature high-pressure generator. FIG. 1 shows a gasket 1 between a pair of anvil bodies 2.
A central space is formed by arranging the cylinder body 1 via 1 and 12, and an electrode plate 6, an intensifying plate 5 and a metal plate 3 are sequentially installed on the anvil body side of the central space part, and Indicates that a pressure medium 7 is installed to form a reaction chamber, and a graphite cylinder 8 filled with cBN raw material 10 is loaded in the reaction chamber.

Reference numeral 4 denotes an energizing metal ring, 9 denotes a salt sealing ring, 13 denotes a graphite lid, φ1 denotes the outer diameter of the reaction chamber, φ2 denotes the outer diameter of the pressure medium, φ3 denotes the inner diameter of the cylinder body,
φ4 is the outer diameter of the gasket 11, H1 is the height of the reaction chamber, H2 is the sum of the thickness of H1 and the thickness of two electrode plates, two pressure intensifier plates and two metal plates, and H3 is the gasket 11 And the height of the contact portion between the gasket 12 and the gasket 12. Furthermore, P
Is the amount of power used, and P1 is the amount of power expressed by the product of the area of the tip of the anvil and the generated pressure.

The generation of pressure by the high-temperature and high-pressure generator is performed by applying a load to a pair of anvil bodies. At that time, the load is distributed between the load applied to the reaction chamber through the booster plate and the load applied to the gasket. However, when the same load is applied, the larger the force applied to the booster plate, the higher the pressure in the reaction chamber. Will be higher. Heating is performed by applying an alternating current to the heater from a pair of anvil bodies via a metal ring for conduction and an electrode plate.

One of the features of the present invention is that the above-mentioned high-temperature and high-pressure generator is used, and as a cBN raw material, hBN, preferably P-B
When synthesizing polycrystalline cBN using an N plate, the blow-out phenomenon and the cracking of the graphite cylinder, which are likely to occur when a pressure of 7 GPa or more is generated under thermodynamically stable conditions of cBN, are reduced by the graphite cylinder (reaction chamber). This was prevented by optimizing the shape and dimensions of ()). That is, the present inventors,
Tests were conducted on the shape and dimensions of the reaction chamber or the components of the high-temperature and high-pressure generator, such as the electrode plate, booster plate, and metal plate, in various cases.As a result, blow-out and cracks in the graphite cylinder showed Not only the dimensions of the chambers and the components, but also greatly depend on the force at the time of generating a pressure of 7 GPa or more. The ratio to the force P1 expressed by the product of the generated pressures (P1
/ P) (hereinafter, this ratio may be referred to as “pressure generation efficiency”) is extremely important.

That is, in the present invention, the pressure generation efficiency needs to be 0.40 or less at a pressure of 7 GPa or more. The pressure generation efficiency changes depending on the dimensions of the reaction chamber (graphite cylinder), the dimensions of the components of the high-temperature and high-pressure generator, and the like. As can be seen from the equation P1 / P, the operating pressure P is determined by the force P1 applied to the reaction chamber.
And the force applied to the gasket (P-P1). According to the study of the present inventors, if P1 is too large, the force applied to the gasket (P-P1) is small. It was confirmed that the gasket could not be sealed, pressure leaked, blowout occurred, and the graphite cylinder was dragged to the gasket side to cause cracks. It has been found that it must be less than 0.40.

In the present invention, the pressure generation efficiency is 0.40
If it is more than 0.45 and not more than 0.45, the graphite cylinder will be broken and cannot be heated, or even if it can be heated, blowout will occur when the power is reduced and pressure is reduced after the end of heating. . Also, if a force is applied in a state where the pressure generation efficiency is expected to exceed 0.45, blowout may occur at the time of pressurization.

Here, the method of calculating the pressure generation efficiency will be described. In order to calculate the pressure generation efficiency, it is necessary to determine the force P1 applied to the reaction chamber. And heat, Ag
Of the so-called Ag by measuring the melting temperature of
A melting method can be employed. When the pressure generated at this time is A and the area of the tip of the anvil is S, the above P1
Is represented by A · S, and the pressure generation efficiency is (A · S) / P. When this is shown by specific numerical values, when the power of 3200 tons is used and the anvil tip area is 13 cm ² , the pressure generation efficiency when the generated pressure is 7.7 GPa is 0.32.

In the present invention, one example of the means for obtaining the above-mentioned pressure generation efficiency is to optimize the dimensions of the reaction chamber.

First, the height H1 of the reaction chamber made of a graphite cylinder
However, the ratio (H1 / φ3) of the height H1 of the reaction chamber to the inner diameter φ3 of the cylinder body is set to 0.48 or more and 0.68 or less. If this ratio exceeds 0.68 and the height of the reaction chamber is increased, the amount of compression of the reaction chamber must be increased when generating the required pressure, and it is inevitable to generate a pressure of 7 GPa or more. Then, the graphite cylinder bends, and the support by the pressure medium is not effective, and cracks occur. When the ratio of H1 / φ3 is less than 0.48, even if the ratio of H2 / H1 and the dimensions of the gasket 11 described later are optimized, the gasket 1
Since the compression allowance of 1 itself cannot be taken, pressure generation becomes difficult, pressure sealing becomes insufficient, and blow-out occurs. In the present invention, the graphite lid 13 may be put on and under the graphite cylinder, but in this case, the thickness of the graphite lid is preferably approximately the same as the thickness of the graphite cylinder. The height H1 of the reaction chamber in the present invention includes the thickness of the graphite lid.

What is important is that the height H1 of the reaction chamber, the two upper and lower electrode plates 6, the two upper and lower pressure plates 5, and the two upper and lower metal plates 3 with respect to the height H1 of the reaction chamber are important. The ratio (H2 / H1) of the total thickness H2 to the total thickness H2 is set to 1.6 or more and 2.3 or less.

In the present invention, the reason why blowout and graphite cylinder cracking can be efficiently prevented by adjusting the ratio of H2 / H1 is as follows. Assuming that H2 is constant, increasing this ratio means reducing the height H1 of the reaction chamber, while reducing this ratio means increasing H1. First, when H1 is increased,
To achieve a given pressure, more compression is required.
In order to increase the compression amount and generate a predetermined pressure, there is an adjustment method such as reducing the thickness of the gasket 12, but this method cannot completely suppress the flow of the gasket 11 during compression. On the other hand, there is a method in which a greater amount of force is applied without relying on the adjustment of the thickness of the gasket 12, but there is a limit to the amount of compression of the gasket, so that a configuration in which H1 is set too large has a limit in pressure generation. The present inventors,
According to the results of the study, it was found that the ratio of H2 / H1 should be 1.6 or more, preferably 1.8 or more in order to generate a pressure of 7 GPa or more without difficulty. on the other hand,
If this ratio is increased, that is, H1 is reduced and a predetermined pressure is generated with a small compression amount,
Since pressure is generated without sufficiently compressing the gasket 11, sealing is insufficient, and blowout is likely to occur. Further investigation on this point revealed that H2 /
It has been found that the upper limit of H1 is 2.3.

What is more important is the pressure medium. The pressure medium 7 covers the outer peripheral portion of the reaction chamber,
It consists of a hollow cylindrical molded body. Its outer diameter φ2 is preferably the same as the diameter of the tip of the anvil body,
Further, the ratio (φ2 / φ3) to the inner diameter φ3 of the cylinder body is set to 0.82 or more and 0.86 or less. The reason is that if this ratio is less than 0.82, the thickness of the gasket 11 must be increased, and the sealing is insufficient and blowout tends to occur. If the ratio exceeds 0.86, the area of the tip of the anvil becomes large, the power per unit area is reduced, and it is difficult to generate a pressure of 7 GPa or more.

Next, regarding the gaskets 11 and 12, the height H3 of the contact portion between the gasket 11 and the gasket 12 should be not less than (H2 / 2) −14 × φ3 / 50 and (H2 / 2) −
It is important to make it 12 × φ3 / 50 or less.
If the value of H3 is smaller than the above lower limit, the gasket 11 becomes thinner and the gasket is not sufficiently compressed, resulting in insufficient pressure sealing and causing blowout. If the value of H3 exceeds the upper limit, the gasket 11
Becomes thick, and the gasket 12 cannot completely suppress the flow, which causes blowout and the like. The outer diameter φ4 of the gasket 11 is preferably 1.5 × φ3 or more and 1.7 × φ3 or less.

When synthesizing cBN using the above-described high-temperature and high-pressure generator of the present invention, the high-temperature and high-pressure generator is preferably a flat belt type, and the pressure generation efficiency is 0.40 or less. Preferably, there is.

Further, as for the diameter of the reaction chamber composed of the graphite cylinder 8, the ratio (φ1 / φ3) of the outer diameter φ1 of the reaction chamber composed of the graphite cylinder to the inner diameter φ3 of the cylinder body is 0.68.
It is preferable to set the following. When the ratio exceeds 0.68 and the outer diameter of the reaction chamber is increased, it becomes difficult to support the graphite cylinder filled with the cBN raw material by the pressure medium, and the graphite cylinder breaks.

According to the present invention, a large amount and stable cBN can be obtained by holding the cBN raw material without a catalyst under the above-mentioned pressure generation efficiency or by holding the cBN raw material without a catalyst using the above-mentioned optimized high-temperature and high-pressure generator. Can be manufactured. Holding pressure is 7 GPa or more, holding temperature is 180
The temperature is preferably 0 ° C. or higher. C filled in the reaction chamber
How much of the BN raw material can be obtained as complete cBN depends on the pressure and temperature. In the case of the same pressure, it is better to increase the temperature. However, if the temperature is too high, c
Because it is out of the stable range of BN and cannot be converted conversely,
The balance between pressure and temperature is important.

Now, one of the motivations that led to the present invention was proposed.
First, as described above, polycrystalline cBN could not be synthesized in large amounts by the direct conversion method in the conventional method. Also, the reason is that under the condition that the working power P applied to the high-temperature and high-pressure generator is constant, the volume P1 initially applied to the reaction chamber decreases due to the volume contraction from hBN to cBN, and the pressure in the reaction chamber decreases. As described above, the pressure decreases and the pressure required for the conversion is reduced.

Under such circumstances, the present inventors have conducted various studies on means for further increasing the amount of cBN synthesized in the above-described method for producing cBN of the present invention. As a result, it is effective to increase the initial pressure. As a measure, this method cannot solve the fundamental problem that even if the synthesis amount can be increased to some extent, the pressure drops at a certain point, and the pressure falls below the convertible pressure.

Therefore, as a result of further study, it was found that it is effective to carry out a supplementary pressure commensurate with the pressure drop while maintaining the cBN under thermodynamically stable conditions to maintain a convertible pressure level. Reached. This supplementary pressure is to make the power P1 applied to the reaction chamber constant or increase during the heat synthesis, and actually increase the power P used in the high-temperature high-pressure generator during the synthesis of cBN. This is achieved by causing How much the power is increased can be arbitrarily selected based on the target amount of cBN synthesis, but it is natural that the required power also increases when the synthesis amount is increased.

Further, it has been found that the above-mentioned pressure drop is also caused by the deformation of the pressure intensifier plate 5. In general, in a high-temperature and high-pressure generator, a zirconia plate is widely used as an intensifying plate, because of its high elastic modulus and low thermal conductivity. However, the present inventors have studied and found that the porosity of the zirconia plate is important, as well as the elastic modulus. This is because, if a material having a high porosity, that is, a material having an insufficient degree of densification, is used, if heated under high pressure, sintering will occur and the pores will be crushed and deformed as a result. Because it goes. Therefore, it is desirable that the zirconia plate used has a small porosity, and it is preferable that the porosity be less than 8%, more preferably less than 4%.

Here, the components of the high-temperature and high-pressure generator used in the present invention will be described. As described above, a zirconia booster plate is preferable as the booster plate. Among them, a zirconia plate having a crystal structure described below is preferable. In other words, zirconia generally has three phases of monoclinic, tetragonal and cubic, coexist with monoclinic and tetragonal, monoclinic and cubic, and tetragonal and cubic. thing,
Further, a single cubic or tetragonal phase is known, and among these, it is known that a monoclinic crystal undergoes a phase transition to a tetragonal crystal under high temperature and pressure to cause volume shrinkage. The present inventors performed synthesis of cBN by using a zirconia plate having the above crystal structure as a booster plate. As a result, there was a correlation between the amount of monoclinic crystals in zirconia and the amount of cBN synthesized. It is found that the use of zirconia plates with a small amount of zirconia increases the amount of synthesized cBN. The reason for this is that if the amount of monoclinic crystals is large, the amount of phase transition under high temperature and high pressure increases, and a kind of deformation called volume shrinkage increases. I found it to be a good thing. From the above, the booster plate suitable for the present invention is cubic and / or
Alternatively, the zirconia plate is made of a tetragonal system and a monoclinic system, and has an Xm value calculated by the above equation (1) of 0.3 or less (including 0).

As the pressure medium, salt is usually used, but preferably 5 to 30% by weight of zirconia powder is mixed in order to improve heat insulation. When the content of the zirconia powder is less than 5% by weight, the heat insulating property is not sufficient, and when the content exceeds 30% by weight, molding becomes difficult. Since the pressure becomes high, the reaction chamber cannot be compressed and a predetermined pressure cannot be developed.

The relative density of the pressure medium is preferably at least 92%, particularly preferably at least 96%. Since the pressure medium is for supporting the reaction chamber consisting of a graphite cylinder,
If the relative density is low, the graphite cylinder bends and cracks occur. Further, in the present invention, in order to further suppress the flow of the pressure medium, the outer diameter of the upper and lower surfaces in contact with the electrode plate is the same as the outer diameter φ2 of the pressure medium and the height is 0.14 × φ.
It is also possible to mount a metal ring called a salt sealing ring 9 having a thickness of 3 or less and a thickness greater than that of a metal ring 4 for electricity to be described later.

The electrode plate 6 is a molybdenum electrode plate, the metal plate 3 is a stainless steel, molybdenum, tungsten metal plate, particularly a stainless steel metal plate. The gasket 11 is a pyrophyllite gasket, a gasket 12. Is a paper gasket.

The cBN raw material used in the present invention is hBN, preferably P-B having a density of 2.05 g / cm ³ or more.
It is an N plate. When P-BN powder is used, the filling amount in the reaction chamber is reduced, and P-BN having a density of less than 2.05 g / cm ³ is used.
-The BN plate has a problem in the generated pressure.

The preferred embodiment of the high-temperature and high-pressure generator used in the present invention will be described below.
A specific description will be given taking the case of 0 mm as an example.

The height H1 of the reaction chamber optimized according to the present invention
Not only the ratio (H1 / φ3) to the inner diameter φ3 of the cylinder body is 0.48 or more and 0.68 or less, but also the height H1 of the reaction chamber and H1 and two upper and lower electrode plates, an intensifier plate and Ratio of the sum H2 to the thickness of the metal plate (H2 / H1)
Is set to 1.6 or more and 2.3 or less. Therefore, when a cylinder having an inner diameter of 50 mm is used and H2 is set as follows, the appropriate reaction chamber height H1 is as follows.

That is, when H2 is 54.8 mm, the appropriate height H1 of the reaction chamber is 24-34 mm.
When H2 is reduced to 51 mm, H1 is 22 to 32 mm. If H1 is increased beyond the upper limit, the amount of compression must be increased in order to generate the same pressure, and it becomes difficult to generate the pressure itself. Further, even if pressure can be generated, the amount of deflection of the reaction chamber increases, and cracks easily occur. On the other hand, when the pressure is lower than the lower limit, when the pressure is generated, the sealing is insufficient and blowout is likely to occur.

In the present invention, the thicknesses of the electrode plate and the metal plate can be arbitrarily selected. However, it is usually preferable that the thickness is 0.01 × φ3 or less with respect to the inner diameter φ3 of the cylinder body. The thickness of the intensifier plate is (H2-H1) / 2.
Is the value obtained by subtracting the thickness of the electrode plate and the thickness of the metal plate from the above value. An energizing metal ring (4) is mounted on the outer periphery of the pressure intensifier plate so that energization can be performed. The energizing metal ring has the same outer diameter as the outer diameter φ2 of the pressure medium, It is preferable to use one having a thickness smaller than that of the salt sealing ring 9 and having the same height as the height of the pressure booster plate.

Next, the thickness of the graphite portion of the reaction chamber made of a graphite cylinder is preferably about 2 to 4% of the inner diameter φ3 of the cylinder body, and is preferably about 50%. Is preferably about 1 mm to 2 mm in thickness. If it is thinner than this range, cracks are likely to occur, and if it is thicker, a large current is required to heat it to a predetermined temperature. In the present invention, the thickness of the graphite cylinder is not limited to the above value, but can be arbitrarily selected according to the electric capacity of the high-temperature and high-pressure generator.

In the present invention, since the preferred ratio (φ1 / φ3) of the outer diameter of the reaction chamber made of a graphite cylinder to the inner diameter of the cylinder body is 0.68 or less, the inner diameter is 50 m.
For a cylinder body of m, the outer diameter of the reaction chamber may be 34 mm or less. In order to more effectively exert the effect of supporting the reaction chamber by the pressure medium, it is required to be 32 mm or less (φ1 / φ3
Is more preferably 0.64 or less.

It is preferable that the outer diameter φ2 of the pressure medium formed of the hollow cylindrical molded body is the same as the diameter of the tip of the anvil body, and the outer diameter φ2 is the inner diameter φ of the cylinder body.
The ratio (φ2 / φ3) to 3 is 0.82 or more, 0.86
From the following, when the inner diameter of the cylinder body is 50 mm, the value of φ2 is 41 mm or more and 43 mm or less.

Further, the dimensions of the gasket 11 used in the present invention are as follows, taking a cylinder having an inner diameter of 50 mm as an example. First, the outer diameter φ4 of the gasket 11
For the inner diameter φ3 of the cylinder body, the allowable range is 1.
Since 5 × φ3 or more and 1.7 × φ3 or less are desirable, 75
mm or more and 85 mm or less. The height H3 of the contact portion with the gasket 12 is (H2 / 2) -14
× φ3 / 50 or more and (H2 / 2) −12 × φ3 / 50 or less, so that when H2 is 54.8 mm as described above, it becomes 13.4 mm or more and 15.4 mm or less, and H2 is 51 mm or less. In this case, 11.5 mm or more, 13.5
mm or less.

Next, in the present invention, when generating a pressure of 7 GPa or more under thermodynamically stable conditions of cBN, the pressure generation efficiency (P1 / P) needs to be 0.40 or less.
If pressure is generated beyond this value, blowout or cracking of the graphite cylinder or the like is likely to occur.

[0060] The pressure generation efficiency is the same even if the same force is used.
It is affected by the height H1 of the reaction chamber, the total height H2 including the reaction chamber, the characteristics of the intensifier plate used, the dimensions of the gaskets 11 and 12, and the like. Therefore, in the present invention, the pressure generating efficiency can be adjusted to 0.40 or less by adjusting the configuration of the entire apparatus and the amount of power used, but can also be adjusted by the thickness of the gasket 12. The gasket 12 used at this time is preferably a paper gasket, and its inner diameter is larger than the outer diameter φ4 of the gasket 11, and its outer diameter is larger than the inner diameter φ3 of the cylinder body.
It is preferably a disk having a size of 220 × φ3 / 50 or less. The material of the paper gasket can be arbitrarily selected, and a predetermined number of the paper gaskets are stacked and used. Regarding the actual number of sheets to be stacked, a preliminary test is performed by actually changing the number of sheets, and the number of sheets is determined from the generated pressure and the used force so that the pressure generation efficiency becomes 0.40 or less. In this case, the gasket 11 is preferably a pyrophyllite gasket.

Here, a cylinder body having an inner diameter of 50 mm is used, an inner diameter of 81 mm, an outer diameter of 200 mm, and a thickness of 0.45 m.
A typical number of paper sheets when the pressure generation efficiency is reduced to 0.40 or less using m / sheet paper gasket 12 will be described.

The diameter of the tip of the anvil is 42 mm, the height H1 of the reaction chamber is 30 mm, the outer diameter φ1 of the reaction chamber is 24 mm,
Using a graphite cylinder having a thickness of 1.5 mm, the thickness of each of a molybdenum electrode plate and a SUS304 metal plate is 0.5 mm,
When the thickness of the zirconia thickening plate is 11.4 mm, the outer diameter φ4 of the pyrophyllite gasket is 80 mm, and the height H3 of the contact portion with the paper gasket is 14.5 mm,
When the number of paper gaskets is 26 or 28 and 2850 tons are applied to each, the generated pressures are 8.3 GPa and 7.6 GPa, respectively, and the pressure generation efficiencies are 0.41 and 0.38, respectively. Therefore, the appropriate number of sheets under this condition is 28.

As one preferred method for producing cBN of the present invention, a cBN raw material is subjected to a pressure of 7 G under thermodynamically stable conditions.
As described above, the power is increased while the pressure is maintained at Pa or more, and an example thereof will be described below.

The inner diameter φ3 of the cylinder body is 50 mm, the diameter of the tip of the anvil is 42 mm, and the height H1 of the reaction chamber is 30 m.
m, the outer diameter φ1 of the reaction chamber is 28 mm or 29.4 mm, the thickness of the graphite cylinder is 1.5 mm for the former, 1.2 mm for the latter, and the thickness of the molybdenum electrode plate is 0 .2 mm, the thickness of the SUS304 metal plate is 0.8 mm, the thickness of the zirconia thickened plate is 11.4 mm, and the outer diameter of the pyrophyllite gasket is φ4.
Is 80 mm, the height H3 of the contact portion with the paper gasket is 14.5 mm, and the outer diameter is 200 mm and the inner diameter is 81 mm.
P-BN filled in a graphite cylinder using two types of high-temperature and high-pressure generators composed of 28 paper gaskets
An example of the thermodynamic stability condition of cBN for making the ratio of the number of P-BN plates in which 99% or more of the plates are converted to cBN to 85% or more is as follows.

The former (the outer diameter of the reaction chamber is 28 mm) and the latter (the outer diameter of the reaction chamber is 29.4 mm)
After applying a power of 2850 tons, power was applied and the temperature was increased to 210
Under ordinary synthesis conditions of holding at 0 ° C. for 40 minutes, and removing the pressure after the completion of heating, the ratio of the number of P-BN plates converted to cBN is about 60% in the former and about 45% in the latter. Therefore, a technique of increasing the power during the synthesis of cBN was adopted, and in both cases, about 20 minutes after the start of heating and holding,
3500 tons for the former and 4000 for the latter
When the power is gradually increased to tons and the power is further maintained for 20 minutes, the ratio of the number of P-BN plates converted to cBN increases to about 85% in all cases.

[0066]

The present invention will be described below more specifically with reference to examples and comparative examples.

[Example 1] The inner diameter of the cylinder body was 50 m.
m, in the central space of the flat belt type high-temperature and high-pressure generator with a diameter of the anvil body tip portion of 42 mm and its peripheral portion,
The following members were arranged according to FIG.

(1) The outer diameter (φ1) of the reaction chamber composed of the graphite cylinder 8 was 24 mm, the wall thickness was 1.5 mm, the thickness of the lid was 1.5 mm, and the height (H1) of the reaction chamber was 30 mm. . (2) The cBN raw material 10 has a density of 2.10 g / cm ³
The above reaction chamber was densely packed with 20 P-BN discs. The total weight of the filled P-BN disc was 19.6 g. (3) The pressure medium 7 was made of sodium chloride containing 10% by weight of zirconia powder, and had a relative density of 97%. (4) The gasket 11 is a pyrophyllite gasket, the outer diameter (φ4) of which is 80 mm, and the height (H) of the contact portion between the gasket 11 and the gasket 12 (paper gasket).
3) was set to 14.5 mm. (5) The booster plate 5 was made of zirconia, had a porosity of 3%, an Xm of 0.15, and a thickness of 11.4 mm. (6) The electrode plate 6 is a molybdenum electrode plate, and the metal plate 3 is a stainless steel plate (SUS plate).
m, and the thickness is 0.2 mm and 0.8 mm, respectively.
And (7) The energizing metal ring 4 has an outer diameter of 42 mm and a thickness of 1 m.
m, the height was 11.4 mm, and the salt sealing ring 9 had an outer diameter of 42 mm, a wall thickness of 1.4 mm, and a height of 6 mm. (8) The gasket 12 is a paper gasket whose outer diameter is 2
Twenty-eight sheets having a size of 00 mm, an inner diameter of 81 mm and a thickness of 0.45 mm were stacked.

In order to measure the pressure generated by the high-temperature and high-pressure generator constructed as described above, Ag pellets were put into the center of the reaction chamber, and the tip of the thermocouple was brought into contact with the Ag.
A thermocouple was drawn out through a pressure medium, pyrophyllite gasket and paper gasket. 3
When a force of 200 tons was applied and heating was performed while maintaining this, the generated pressure was examined based on the melting temperature of Ag.
It was 0 GPa. Also, when P1 / P was calculated from this value, it was 0.35.

Next, cBN was synthesized under the following conditions using the high-temperature and high-pressure generator configured as described above. That is, first, the power was gradually applied to 3200 tons, and when the power reached this power, heating was started while maintaining the power, and the temperature was raised to 2100 ° C. After holding at this temperature for 40 minutes, stop heating and gradually reduce the power to return to atmospheric pressure.
A sample was collected.

The recovered sample was a black disk-shaped plate, and the surface of each plate was measured by an X-ray diffraction method, and the amount of conversion to cBN was measured by the following equation (2). Conversion amount to cBN% = IcBN111 × 100 / (IcBN111 + IhBN002) (2) where IcBN111 and IhBN002 are the X-ray diffraction intensities of the cBN111 plane and the hBN002 plane, respectively.

As a result, P-BN converted to 97% or more
The total weight of the plate is 15.7 g, which is 80% of the raw material charge.

Next, a test was conducted by changing various conditions of cBN synthesis. In the following Examples, the plate thickness of the zirconia intensifier was adjusted so that H2 / H1 was as shown in Table 2.

Example 2 The outside diameter (φ1) of the reaction chamber was 28
mm, and pressure measurement and cBN synthesis were performed in the same manner as in Example 1 except that a P-BN plate matching the dimensions was filled.

Example 3 The outside diameter (φ1) of the reaction chamber was 3
Pressure measurement and cBN synthesis were carried out in the same manner as in Example 1, except that the thickness of the graphite cylinder was 1.4 mm and the thickness of the graphite cylinder was 1.2 mm.

Example 4 The number of paper gaskets was 26,
Pressure measurement and cBN synthesis were performed in the same manner as in Example 3 except that the power was set at 2850 tons.

Example 5 Immediately after the heating and holding, the power was gradually increased to 3500 tons over 20 minutes.
Pressure measurement and cBN synthesis were performed in the same manner as in Example 2 except that the heating was performed for a minute.

Example 6 Immediately after heating and holding, the power was gradually increased to 4000 tons over 20 minutes.
Pressure measurement and cBN synthesis were performed in the same manner as in Example 4 except that the heating was performed for a minute.

Example 7 A raw material P-BN plate having a density of 2.05 g / cm ³ was used, the outer diameter (φ1) of the reaction chamber was 28 mm, the height (H1) of the reaction chamber was 27 mm, and the pressure was A medium containing 15% zirconia powder and a zirconia intensifier having a porosity of 4% and an Xm of 0.20 were used as the medium, and the number of paper gaskets was 31.
The pressure measurement and c were performed in the same manner as in Example 1 except that the sheet was heated at 2050 ° C. for 30 minutes with the strength of 2850 tons.
BN was synthesized.

Example 8 The height (H1) of the reaction chamber was 24
mm, the total height (H2) including the height of the reaction chamber is 5
Pressure measurement and cBN were performed in the same manner as in Example 7 except that the height (H3) of the contact portion between the gasket 11 and the gasket 12 was set to 14.7 mm, and the number of paper gaskets was set to 30. Was synthesized.

Example 9 The height (H1) of the reaction chamber was 24
mm, the total height (H2) including the height of the reaction chamber is 3
A method similar to that of Example 7 except that the height (H3) of the contact portion between the gasket 11 and the gasket 12 was 6.3 mm, the number of paper gaskets was 27, and the power was 3500 tons. Performed pressure measurement and cBN synthesis.

Example 10 The height (H1) of the reaction chamber was 3
4 mm, the sum of the heights including the height of the reaction chamber (H2) is 6
2.2 mm, the height (H3) of the contact portion between the gasket 11 and the gasket 12 was 18.2 mm, a zirconia powder-containing product of 20% as a pressure medium, and a porosity of 3.5% as a zirconia intensifier plate. Pressure measurement and cBN synthesis were carried out in the same manner as in Example 7, except that each having Xm of 0.30 was used, and 28 paper gaskets and a strength of 3200 were used.

Example 11 The total height (H2) including the height of the reaction chamber was 54.4 mm, the height (H3) of the contact portion between the gasket 11 and the gasket 12 was 14.3 mm,
Pressure measurement and cBN synthesis were performed in the same manner as in Example 10 except that the power was set to 3500 tons.

Example 12 A raw material P-BN plate having a density of 2.12 g / cm ³ was used, and the outer diameter of the reaction chamber (φ
1) is 31.4 mm, the total height (H2) including the height of the reaction chamber is 69 mm, and the gasket 11 and the gasket 12
The height (H3) of the contact portion with 21.6 mm, a 30% zirconia powder-containing product as a pressure medium, and a zirconia intensifier plate having a porosity of 5% and an Xm of 0.15 are used, respectively. 2650 tons of power and 20 heating
Pressure measurement and cBN synthesis were performed in the same manner as in Example 1 except that the temperature was changed to 50 ° C. for 30 minutes.

Example 13 The outside diameter (φ1) of the reaction chamber was 3
Pressure measurement and cBN synthesis were performed in the same manner as in Example 1 except that the thickness was set to 4 mm.

Example 14 The outside diameter (φ1) of the reaction chamber was 2
Pressure measurement was carried out in the same manner as in Example 1 except that the height (H3) of the contact portion between the gasket 11 and the gasket 12 was 15.4 mm, and a 5% zirconia powder-containing product was used as a pressure medium. And cBN were synthesized.

Example 15 The outside diameter (φ1) of the reaction chamber was 3
Pressure measurement and cBN synthesis were performed in the same manner as in Example 14 except that the height (H3) of the contact portion between the gasket 11 and the gasket 12 was set to 13.4 mm.

Example 16 The outside diameter (φ1) of the reaction chamber was 2
Same as Example 13 except that 4 mm, the outer diameter (φ4) of the gasket 11 was 75 mm, the paper gasket was φ200 mm × φ76 mm, and a zirconia intensifier plate having a porosity of 5% and an Xm of 0.15 was used. The pressure measurement and the synthesis of cBN were performed by various methods.

Example 17 The outside diameter (φ1) of the reaction chamber was 2
Same as Example 13 except that 4 mm, the outer diameter (φ4) of the gasket 11 was 85 mm, the paper gasket was φ200 mm × φ86 mm, and a zirconia intensifier plate having a porosity of 5% and an Xm of 0.15 was used. The pressure measurement and the synthesis of cBN were performed by various methods.

Example 18 The diameter of the tip of the anvil body was 41 mm, the outer diameter of the reaction chamber (φ1) was 28 mm, the height of the reaction chamber (H1) was 28 mm, and the height including the height of the reaction chamber was 28 mm. The sum (H2) is 50.4 mm, the height (H3) of the contact portion between the gasket 11 and the gasket 12 is 12.3 mm, a product containing 5% zirconia powder as a pressure medium, and a porosity as a zirconia booster plate. Xm is 0.25 at 5%
Are used. Further, the number of paper gaskets is 29, the strength is 3050 tons, and 30 g at 2050 ° C.
Pressure measurement and cBN synthesis were performed in the same manner as in Example 1 except that the heating was performed for a minute.

Example 19 Pressure measurement and cBN synthesis were performed in the same manner as in Example 18 except that the diameter of the tip of the anvil body was 43 mm.

[Embodiment 20] The inner diameter of the cylinder body is 40 m.
The following members were arranged according to FIG. 1 in the central space portion and the peripheral portion of the flat belt type high-temperature and high-pressure generator having a diameter of 33.6 mm at the tip of the anvil body.

(A) The outer diameter (φ1) of the reaction chamber composed of the graphite cylinder 8 is 19.2 mm, the wall thickness is 1.2 mm, the thickness of the lid is 1.5 mm, and the height (H1) of the reaction chamber is 24 mm. And (B) The cBN raw material 10 has a density of 2.12 g / cm ³
The above reaction chamber was densely packed with 12 P-BN disks. The total weight of the filled P-BN disc was 9.9 g. (C) The pressure medium 7 is made of salt containing 10% by weight of zirconia powder, and its relative density is set to 96%. (D) The gasket 11 is a pyrophyllite gasket, the outer diameter (φ4) of which is 64 mm, and the height (H) of the contact portion between the gasket 11 and the gasket 12 (paper gasket).
3) was set to 11.6 mm. (E) The intensifier plate 5 was made of zirconia, had a porosity of 3%, an Xm of 0.15, and a thickness of 9.1 mm. (F) The electrode plate 6 is a molybdenum electrode plate, and the metal plate 3 is a stainless steel plate (SUS plate).
6 mm and thicknesses of 0.2 mm and 0.6 mm, respectively.
mm. (G) The energizing metal ring 4 has an outer diameter of 33.6 mm, a wall thickness of 0.8 mm, and a height of 9.1 mm.
Had an outer diameter of 33.6 mm, a thickness of 1.2 mm, and a height of 5 mm. (H) The gasket 12 is a paper gasket, and its outer diameter 1
Twenty-two sheets each having a size of 60 mm, an inner diameter of 65 mm, and a thickness of 0.45 mm were stacked.

The above-mentioned high-temperature and high-pressure generator has a power of 2050.
Pressure measurement and cBN synthesis were performed in the same manner as in Example 1 except that the weight was reduced.

Example 21 The outer diameter (φ1) of the reaction chamber was 2
Pressure measurement and cBN synthesis were performed in the same manner as in Example 20, except that the thickness was set to 2.4 mm.

Example 22 The outer diameter (φ1) of the reaction chamber was 2
Pressure measurement and cBN synthesis were performed in the same manner as in Example 20, except that the thickness was set to 5.1 mm and the thickness of the graphite cylinder was set to 1 mm.

[Example 23] The height (H1) of the reaction chamber was set to 1
9.2mm, sum of height including height of reaction chamber (H2)
Is 30.7 mm, the height (H3) of the contact portion between the gasket 11 and the gasket 12 is 5.0 mm, and 1
A 5% zirconia powder-containing product and a zirconia booster plate having a porosity of 4% and an Xm of 0.20 were used, and the number of paper gaskets was 21 and the strength was 225.
0 tons and heated at 2050 ° C for 30 minutes,
Pressure measurement and cBN synthesis were performed in the same manner as in Example 21.

Example 24 The height (H1) of the reaction chamber was set to 2
7.2 mm, sum of heights including height of reaction chamber (H2)
50.0 mm, the height (H3) of the contact portion between the gasket 11 and the gasket 12 is 14.7 mm, a product containing 20% zirconia powder as a pressure medium, and 3.5% porosity Xm as a zirconia intensifier plate. 0.30, respectively, except that it was heated at 2050 ° C. for 30 minutes.
Pressure measurement and cBN synthesis were performed in the same manner as in Example 21.

[Example 25] The outer diameter (φ1) of the reaction chamber was 2
Pressure measurement and cBN synthesis were performed in the same manner as in Example 20, except that the distance was 7.2 mm.

[Example 26] The outer diameter (φ1) of the reaction chamber was 2
2.4 mm, the height (H1) of the reaction chamber was 21.6 mm, a product containing 15% zirconia powder as a pressure medium, and a zirconia intensifier plate having a porosity of 4% and an Xm of 0.20 were used. 1820 tons at 2050 ° C
Pressure measurement and cBN synthesis were performed in the same manner as in Example 20, except that the heating was performed for 30 minutes and the number of paper gaskets was changed to 25.

[Comparative Example 1] Pressure was measured in the same manner as in Example 4 except that the number of paper gaskets was changed to 23. Blow-out occurred at 1200 tons during depressurization.

[Comparative Example 2] Pressure measurement and cBN synthesis were performed in the same manner as in Example 4, except that the height (H3) of the contact portion between the gasket 11 and the gasket 12 was 12.4 mm. . As a result, during the synthesis of cBN, 2100 ° C.
Immediately after the holding was started, heating could not be performed due to the graphite cylinder crack.

Comparative Example 3 The total height (H2) including the height of the reaction chamber was 64.8 mm, and the height (H3) of the contact portion between the gaskets 11 and 12 was 19.5 mm. Other than that, the pressure measurement and cB were performed in the same manner as in Example 7.
Synthesis of N was performed. As a result, during synthesis of cBN, heating could not be performed due to graphite cylindrical cracks during the temperature rise.

Comparative Example 4 The total height (H2) including the height of the reaction chamber was 60.0 mm, and the height (H3) of the contact portion between the gaskets 11 and 12 was 17.1 mm. Except for this, pressure was measured in the same manner as in Example 8, but blowout occurred when 780 tons were applied during pressurization.

Comparative Example 5 Pressure measurement and cBN were performed in the same manner as in Example 10 except that the height (H3) of the contact portion between the gasket 11 and the gasket 12 was 20.1 mm.
Was synthesized. As a result, the generated pressure was less than 7 GPa, and PBN which showed a conversion of 97% or more in the synthesis of cBN.
-There was no BN plate.

Comparative Example 6 The total height (H2) including the height of the reaction chamber was 51.0 mm, and the height (H3) of the contact portion between the gaskets 11 and 12 was 12.6 mm. Other than the above, the pressure measurement and c were performed in the same manner as in Example 11.
BN was synthesized. As a result, the generated pressure was less than 7 GPa, and none of the P-BN plates showed a conversion of 97% or more in the synthesis of cBN.

[Comparative Example 7] The diameter of the tip of the anvil body was 4
Pressure was measured in the same manner as in Example 18 except that the thickness was set to 0 mm. However, blowout occurred when 1,400 tons were applied during pressurization.

[Comparative Example 8] The diameter of the tip of the anvil body was 4
Pressure measurement and cBN synthesis were performed in the same manner as in Example 19 except that the thickness was set to 4 mm. As a result, the generated pressure was less than 7 GPa, and none of the P-BN plates showed a conversion of 97% or more in the synthesis of cBN.

A summary of Examples 1 to 26 and Comparative Examples 1 to 8 is shown in the table. Tables 1 to 3 mainly show the experimental conditions in Examples 1 to 26, and Tables 4 to 6 mainly show the results. Table 7 shows the experimental conditions of Comparative Examples 1 to 8, and Table 8 mainly shows the results.

[0110]

[Table 1]

[0111]

[Table 2]

[0112]

[Table 3]

[0113]

[Table 4]

[0114]

[Table 5]

[0115]

[Table 6]

[0116]

[Table 7]

[0117]

[Table 8]

[0118]

According to the production method of the present invention, polycrystalline cBN having high strength and high toughness can be produced in large quantities and stably.

Further, according to the high-temperature and high-pressure generator of the present invention, it is possible to stably generate high-temperature and high-pressure capable of stably producing high-strength and high-toughness polycrystalline cBN in a large amount. The high-temperature and high-pressure generator according to the present invention is not limited to the use of synthesizing cBN, but can also be used for synthesizing diamond or the like.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a cBN synthesizer.

[Explanation of symbols]

Reference Signs List 1 cylinder body 2 anvil body 3 metal plate 4 energizing metal ring 5 booster plate 6 electrode plate 7 pressure medium 8 graphite cylinder 9 salt sealing ring 10 cBN raw material 11 gasket 12 gasket 13 graphite lid φ1 outside diameter of reaction chamber φ2 pressure Outer diameter of medium φ3 Inner diameter of cylinder body φ4 Outer diameter of gasket 11 H1 Height of reaction chamber H2 Height H1 of reaction chamber, two electrode plates 6, two booster plates 5, two metal plates 3 H3 Height of contact part between gasket 11 and gasket P Working force P1 Force expressed by product of anvil tip area and generated pressure

Claims (18)

[Claims] 1. A central space is formed by disposing a cylinder body (1) between a pair of anvil bodies (2) via gaskets (11) and (12), and the central space is located on the anvil body side. An electrode plate (6), an intensifying plate (5), and a metal plate (3) are sequentially installed on the cylinder, and a pressure medium (7) is installed on the cylinder body side to form a reaction chamber. In a method in which a graphite cylinder (8) filled with a cBN raw material (10) is charged into the reaction chamber of the apparatus and held under thermodynamically stable conditions of the cBN, the area of the anvil tip and the generation of the anvil tip relative to the working power (P) are obtained. A method for producing polycrystalline cubic boron nitride, wherein a ratio (P1 / P) to a force (P1) expressed as a product of pressures is set to 0.40 or less under a pressure of 7 GPa or more. 2. The method according to claim 1, wherein the high-temperature and high-pressure generator is of a flat belt type. 3. A central space is formed by arranging a cylinder body (1) between a pair of anvil bodies (2) via gaskets (11) and (12), and the central space side of the anvil body side. An electrode plate (6), an intensifying plate (5), and a metal plate (3) are sequentially installed on the cylinder, and a pressure medium (7) is installed on the cylinder body side to form a reaction chamber. In a method in which a graphite cylinder (8) filled with a cBN raw material (10) is charged into the above-mentioned reaction chamber of the apparatus and held under thermodynamically stable conditions of cBN, the following (a) to (d)
A method for producing polycrystalline cubic boron nitride, characterized in that the method is carried out under the following conditions. (A) The ratio (H1 / φ3) of the height (H1) of the reaction chamber to the inner diameter (φ3) of the cylinder body is 0.48 or more and 0.68 or less. (B) The height (H1) of the reaction chamber relative to the height (H1) of the reaction chamber
1) and the sum of the thicknesses of the electrode plate, the booster plate and the metal plate (H
2) The ratio (H2 / H1) is 1.6 or more and 2.3 or less. (C) The ratio (φ2 / φ3) of the outer diameter (φ2) of the pressure medium to the inner diameter (φ3) of the cylinder body is 0.82 or more and 0.8
6 or less. (D) The height (H3) of the contact portion between the gasket (11) and the gasket (12) is (H2 / 2) -14 × φ3 / 50.
Above, (H2 / 2) −12 × φ3 / 50 or less. 4. The method according to claim 3, wherein the high-temperature and high-pressure generator is of a flat belt type. 5. The thermodynamic stability condition of cBN is such that a ratio (P1 / P) of a force (P1) represented by a product of an anvil tip area and a generated pressure to a working force (P) is 0.40 or less. 4. The method of claim 3, wherein 6. A ratio (φ1 / φ3) of an outer diameter (φ1) of a reaction chamber comprising a graphite cylinder to an inner diameter (φ3) of a cylinder body.
4. The method of claim 3 wherein is less than or equal to 0.68. 7. The method according to claim 1, wherein the power is increased while the cBN is maintained under thermodynamically stable conditions.
7. The method according to any one of claims 1 to 6. 8. The cBN raw material (10) has a density of 2.05 g /
The method according to claim 7, wherein the pyrolytic boron nitride plate has a size of ³ cm3 or more. 9. The method according to claim 7, wherein the electrode plate (6) is made of molybdenum, the booster plate (5) is made of zirconia, and the metal plate (3) is made of stainless steel. 10. The method according to claim 7, wherein the gasket is a pyrophyllite gasket and the gasket is a paper gasket. 11. The pressure medium (7) is a hollow cylindrical molded product having a relative density of 92% or more and containing sodium chloride containing 5 to 30% by weight of zirconia powder as a component.
The described method. 12. A zirconia intensifier plate comprising a cubic crystal and / or
8. The method according to claim 7, comprising a tetragonal system and a monoclinic system, wherein the Xm value calculated by the following equation (1) is 0.3 or less (including 0). (Equation 1) 13. A central space is formed by disposing a cylinder body (1) between a pair of anvil bodies (2) via gaskets (11) and (12), and the central space side of the anvil body. , An electrode plate (6), an intensifier plate (5) and a metal plate (3) are sequentially installed, and a pressure medium (7) is installed on the cylinder body side to form a reaction chamber. (8) A high-temperature and high-pressure generating apparatus characterized in that the following conditions (a) to (d) are further added to the apparatus loaded with (8). (A) The ratio (H1 / φ3) of the height (H1) of the reaction chamber to the inner diameter (φ3) of the cylinder body is 0.48 or more and 0.68 or less. (B) The height (H1) of the reaction chamber relative to the height (H1) of the reaction chamber
1) and the sum of the thicknesses of the electrode plate, the booster plate and the metal plate (H
2) The ratio (H2 / H1) is 1.6 or more and 2.3 or less. (C) The ratio (φ2 / φ3) of the outer diameter (φ2) of the pressure medium to the inner diameter (φ3) of the cylinder body is 0.82 or more and 0.8
6 or less. (D) The height (H3) of the contact portion between the gasket (11) and the gasket (12) is (H2 / 2) -14 × φ3 / 50.
Above, (H2 / 2) −12 × φ3 / 50 or less. 14. The apparatus according to claim 13, wherein the high-temperature and high-pressure generator is of a flat belt type. 15. A ratio (φ1 / φ1) of an outer diameter (φ1) of a reaction chamber comprising a graphite cylinder to an inner diameter (φ3) of a cylinder body.
14. The method according to claim 13, wherein 3) is 0.68 or less.
Or the apparatus of 14. 16. The electrode plate (6) is made of molybdenum, the booster plate (5) is made of zirconia, the metal plate (3) is made of stainless steel,
Apparatus according to claim 13 or 14, characterized in that the gasket (11) is a pyrophyllite gasket and the gasket (12) is a paper gasket. 17. The pressure medium (7) is a hollow cylindrical molded body having a relative density of 92% or more and containing sodium chloride containing 5 to 30% by weight of zirconia powder as a component.
15. The device according to 3 or 14. 18. The zirconia intensifier plate may be cubic and / or
15. The apparatus according to 13 or 14, comprising a tetragonal system and a monoclinic system, wherein the Xm value calculated by the following equation (1) is 0.3 or less (including 0). (Equation 2)