JPS6049153B2 - Diamond sintered body with crystal grains arranged in a specific direction and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diamond sintered body with crystal orientation aligned in a specific direction and a method for manufacturing the same.

In recent years, with the development of ultra-high pressure technology, diamond abrasive grains have been artificially synthesized and used in large quantities for stone cutting blades, polishing wheels, etc., and the amount used far exceeds that of natural diamonds. Diamond sintered bodies have also been manufactured using these materials as raw materials, and have been used in wear-resistant tools such as cutting tools and wire drawing dies, and their applications have expanded to a wide range of areas. Artificial diamond abrasive grains currently available on the market are roughly divided into three types. That is, diamond for cutting blades (abbreviated as SD) has a good cubic crystal shape, diamond for metal bonding (abbreviated as MD) has a crystal shape that is slightly inferior to SD but generally cubic, and diamond for metal binding (abbreviated as MD) that has a crystal shape that is slightly inferior to SD. It is a resin-bonded diamond (abbreviated as RD) that is easily crushed. SD and Soku have mechanical properties that are extremely difficult to crush compared to RD, and their maximum size is approximately 300 ~
It is 500μ. Now, the diamond sintered bodies currently on the market are the above-mentioned SD, MD, and R diamond raw materials.
Three types (D) are selected depending on the application, and are obtained by adding metals such as CO and Nl as binders and sintering diamond at high temperature and high pressure, which is thermodynamically stable. .

The size of the diamond particles used is 10μ to 1
A value between 00p and 00p is appropriately selected depending on the application. As mentioned above, such diamond sintered bodies have already been applied to cutting tools and wire drawing dies, but if they are to be applied to heat sinks that take advantage of diamond's good thermal conductivity, the following will be applied. It has its drawbacks. We used diamonds like RD, which are easily crushed, as raw materials! In some cases, even if particles with large dimensions are used, they will be crushed during the pressurization process, resulting in fine particles, which will increase the number of grain boundaries per unit length in the heat conduction direction and reduce thermal conductivity. let Furthermore, when diamonds that are difficult to fracture such as SD and MD are used as a raw material, sintering is difficult compared to RD, and the volume of the grain boundary increases, so a large amount of metal binder is required. This value is also lower than the thermal conductivity of diamond single crystal. The thermal conductivity of conventionally obtained diamond sintered bodies is 0.4-0.8Ca11cm-Sec-D
eg, the thermal conductivity of a type 1a single crystal of 4 diamond is 2.
It is significantly lower than 2Ca11cm・Sec●Deg. In view of these points, the present invention uses diamond particles with an elongated shape in which the ratio of the length of the long axis to the short axis is 2 or more. It is based on the recognition that a diamond sintered body having good thermal conductivity can be obtained by reducing the number of grain boundaries per unit length in the conduction direction.

That is, the present invention directly converts a raw material carbonaceous material into diamond as individual diamond crystal grains constituting a diamond sintered body, and has an elongated shape in which the length ratio of the long axis to the short axis is 2 or more. In addition, by arranging the long axis direction of most of the particles in a specific direction in the sintered body and sintering the individual particles together, good thermal conductivity can be achieved. An object of the present invention is to provide a diamond sintered body having the following properties. It will be understood that when the sintered body obtained according to the present invention is used as a heat sink, the long axis direction should be used as the direction of heat conduction.

A diamond sintered body obtained by the present invention is schematically shown in FIGS. 5 and 6.

Figure 5 shows the state in which the long axes of the majority of crystal grains are aligned in the thickness direction in a disc-shaped sintered body, and Figure 6 shows the state in which the long axes of the majority of crystal grains are aligned in the thickness direction in a disc-shaped sintered body. FIG. 2 is a cross-sectional view showing a state in which the long axes of the grains are arranged in the radial direction.The size of each diamond grain in the sintered body obtained by the present invention is, for example, such that the length of the short axis is 20 to 80μ. , the length of the major axis is 50 μ ~ 400
In most cases, the ratio of the length of the long axis to the short axis is 2 or more across μ, with the short axis being 40μ and the long axis being 200μ.
occupies the majority of them. A method for manufacturing a diamond sintered body according to the present invention having such characteristics will be described below. The gist of this manufacturing method is to use graphite as a raw material carbonaceous material to obtain the structure of the sintered body as described above. It consists of two steps: synthesizing crystal grains with the long axes of the majority of crystal grains aligned in a specific direction, and sintering these grains together to form a continuous diamond phase.

One of the essential differences from conventional techniques for obtaining diamond sintered bodies is that graphite is used instead of diamond as a starting material, and the conversion of graphite to diamond and sintering are performed at the same time. It is in. Another method is to align the crystal alignment in a specific direction.

It is a well-known fact that there is a correlation with the growth direction of diamond crystals (in the case of the long axis direction) or the direction of penetration of the eutectic melt of catalyst metal and carbon, but the present invention specifies these directions. It is based on the discovery of a new method to align the One way to control the melt infiltration process is to newly provide a metal layer that is inert to the so-called diamond synthesis at the interface between the catalyst metal and the raw carbonaceous material, and the other method is to control the melt penetration process. The purpose is to heat the metal and carbon from the eutectic temperature particularly rapidly. Although it is not strictly understood why these methods align the long axes of synthesized crystals in a particular direction, it is thought to be as follows.
This will be explained based on FIG. FIG. 1 is a pressure/temperature phase diagram of carbon, which shows the synthesis region of diamond. The wire oil is a thermodynamic equilibrium line between diamond and graphite, and the higher temperature side than AB is the stable region of graphite, and the lower temperature side is the stable region of diamond. Line CD is the eutectic line between the catalyst metal and carbon under high pressure. The one in the figure is Nj-
C is a eutectic line.

The shaded area EFGH is the appropriate pressure/temperature area for the present invention. Further, the line LM in the figure is for explaining the state of temperature increase, and the L point indicates the eutectic temperature and the M point indicates the experimental temperature. In the case of the known diamond synthesis method in which an inert metal layer is not interposed at the interface between the catalyst metal and the raw carbon, when the temperature of the reaction chamber reaches the eutectic temperature during the heating process (Fig. At point L), a melt is generated at the interface.

As the temperature rises from point L to point M, the melt penetrates into the raw carbon and diamond crystals begin to crystallize at various locations. However, near point L, the viscosity of the melt is high and the rate of penetration is slow, so diamond crystals do not grow long and thin, and many nuclei are generated at various locations, producing fine, irregularly shaped diamonds. However, in the case of a Yang bond with an inactive live metal layer, the carbon and the catalyst metal are not in direct contact even when the temperature reaches the L point, so the inert metal finishes diffusing into the catalyst metal. A eutectic melt of catalyst metal and carbon will not be formed until That is, the apparent eutectic line CD
This means that the temperature is on the high temperature side. Moreover, since the temperature is higher, a low viscosity melt can be obtained, which increases the penetration rate and makes it easier for elongated crystals to grow, and it is understood that their long axes coincide with the growth direction and are uniformly aligned. Ru. Further, the effect of rapidly heating the catalyst metal and carbon from the eutectic temperature is considered as follows.

When heating is carried out rapidly, the eutectic melt generated at point L in FIG. 1 changes from a high viscosity liquid to a low viscosity liquid in a short period of time, and rapidly penetrates into the carbonaceous material. Therefore, the crystallized diamond grows in the direction of its penetration, takes on an elongated shape, and moreover, its major axis is aligned in a certain direction. However, when heating is carried out slowly, the viscosity of the melt is high as described above, so that the melt penetrates slowly, so that the crystallized diamond does not grow long and thin, and its long axes are not aligned in a certain direction. For example, if the temperature is raised from room temperature to point L in Figure 1 in 5 minutes, and then from point L to point M at a rate of 30°C/min, each particle is aligned in the long axis direction. The ratio of the length of each particle's long axis to short axis is 1 to 1.
．． Many cases close to 5 were observed. However, if heating is carried out at a very rapid temperature increase rate of, for example, 1500'C/min, the possibility of damaging the apparatus increases, so the faster the temperature increase rate, the better. The preferred range is 100°C/min to 1200°C/min. It will be understood that these two methods are each effective independently, as described above. It will be understood that it is possible to use these two methods in combination. Moreover, it is clear that even better results can be obtained due to the synergistic effect of both methods. In this way, each of the diamond crystal particles is arranged in a specific direction so that the ratio of the length of the long axis to the short axis is 2 or more, and the synthesized diamond crystal particles are sintered together. This can be achieved by holding the EFGH in a favorable pressure/temperature range for a certain period of time (') indicated by diagonal lines in FIG.

Suitable holding times vary depending on pressure and temperature conditions and cannot be generally defined, but are preferably in the range of 5 minutes to 3 minutes. If it is less than 5 minutes, sintering will not occur sufficiently, and if it is more than 3 minutes, it is uneconomical and will only unnecessarily shorten the life of the device.

Known catalyst metals can be used in the present invention.

That is, Fe, Ni, CO, Cr, Mn and alloys thereof are preferred. In the case of a sample structure as shown in FIG. 3, a disk-like shape is preferable, and in the case of a sample structure as shown in FIG. 4, a foil-like material is used by wrapping it around the outer periphery of the graphite. The amount of these substances should be selected depending on the amount of graphite used and the properties that the sintered body should have.

In other words, the amount of catalyst metal is 5% relative to the total weight of graphite and catalyst metal.
If a catalyst metal of 0 Wt% or more is used, diamond particles will grow, but a large amount of catalyst metal will remain in the gaps between the particles, and the particles will not sinter together, resulting in a decrease in thermal conductivity, especially when used as a heat sink material. This is not preferable because it lowers the temperature. On the other hand, if less than 5 wt % of the catalyst metal is used, unconverted graphite remains and the diamond particles do not sinter, which also does not serve the purpose. A good range is between 5 and 30 wt%. Since the metal inactive for diamond synthesis used in the present invention comes into contact with carbon as described above, the most effective metal is a metal that cannot act as a catalyst for diamond.

In this sense, Au, Ag, Cu, Al, Zn, Sn, Pb
can be used. Further, even if a metal reacts with carbon to form a carbide, it can be used as an inert metal in the diamond synthesis of the present invention if it has a higher melting point than the catalyst metal used. These include Pt, Ti, Zr, Hf, ■, Ta, Nb
, MO, W et al. Among these metals, the one with the most remarkable effect is listed below. Methods for interposing these inert metals at the interface between the catalyst metal and the carbonaceous material include plating methods, vacuum evaporation methods, powder coating methods, methods of sandwiching foil-like materials, and ion sputtering methods. Depending on the required amount, purity, economic efficiency, etc. selected.
In view of these aspects, the preferred method is vacuum evaporation. The required amount of these inert metals is determined based on the type of catalyst metal used, the performance of the reactants, and the heating conditions. In the case of the most preferred Au, 0.1 wt% based on the catalyst used
~5 Wt% gives good results. For example, 100μ
When using an Nj catalyst having a thickness of 500A to 2μ when the heating rate is 50'C/min, the appropriate thickness of the Au layer is 500A to 2μ. In the case of 500A or less, diamonds grown in a certain direction are not observed, and fine diamonds 4 are observed.
It was a dense mass of de.

Furthermore, when gold foil with a thickness of 5 μm was used, the amount of diamond produced was small and did not reach a sintered state. Regarding the pressure and temperature conditions necessary to obtain a sintered body having an arrangement of diamond crystal grains grown in a certain direction, the shaded area EFGH shown in FIG. 1 gives good results.

EF is a line indicating a temperature 200°C higher than the eutectic line CD of catalyst metal and carbon, FG is a line where the pressure is 65 Kb, and G
H is 100 from the thermodynamic equilibrium line of diamond and graphite
This is a straight line indicating a temperature that is ℃ lower. A minimum pressure of 65 Kb is required. If the reaction pressure does not reach 65 Kb, the raw carbonaceous material graphite often remains unconverted. When the temperature is below line 9EF and above CD, that is, when a Ni catalyst is used, for example, at about 1500° C., diamonds are formed, but sufficiently grown crystals cannot be obtained. In addition, under temperature conditions near the equilibrium wire oil, a shape that does not grow selectively in one direction but develops uniformly in all directions, such as a dice-shaped 6
The majority are octahedral or octahedral. In this sense, the EFGH region shown in FIG. 1 is preferable. In the sintered body obtained by the present invention, the long axes of the diamond particles are mostly aligned in a specific direction.

If this direction is used as the direction of heat conduction, high thermal conductivity close to that of a natural diamond single crystal can be obtained. The diamond particles that make up this sintered body have an elongated shape,
The length of the major axis is approximately 200μ, and the thickness normally required as a heat sink material for semiconductor devices is 300μ to 500μ.
This is because the number of grain boundaries in the direction of heat conduction is small because of μ. Furthermore, this sintered body contains a catalytic metal and has electrothermal conductivity due to its continuous structure.

Therefore, when this sintered body is used as a heat sink material that requires electrical conductivity, such as in a semiconductor laser, it is suitable because it can also serve as an electrode. However, when used as a heat sink material for Impatt diodes, Gunn diodes, etc., electrical insulation is required. Even in such cases, by treating the sintered body of the present invention with a strong acid such as aqua regia to dissolve and remove the catalyst metal contained in the sintered body, it is possible to create a diamond sintered body with electrical insulation properties. It can be used as a heat sink material in such fields. For example, this sintered body having a specific resistance of 0.1Ωα was placed in boiling aqua regia for about 24T1.
! By performing the treatment for a period of f, a sintered body having a resistivity of about 1α5 order could be obtained. Further, the sintered body obtained by the present invention has crystal orientation in a certain specific direction, and when examined, it was found to have crystallographic orientation. That is, 1 parallel to the plane perpendicular to the growth direction of the diamond crystal.
Eleven sides were formed. Utilizing such orientation, high-performance wire drawing dies and dressers can be obtained. R. According to Bellman's book 64 Physical Properties of Diamond, the abrasion resistance of diamond varies depending on the direction of the crystal planes, and the best abrasion resistance is said to be in the <100> direction of the 100 planes. . That is, if the hole direction J of the wire drawing die is provided in a direction perpendicular to the 100 plane, a wire drawing die with excellent wear resistance can be obtained. Also, since this direction is the direction that is most resistant to cleavage, a very good wire drawing die can be obtained. Now, when using the diamond sintered body according to the present invention as a wire drawing die or as a dresser, the above-mentioned 100〉 direction of the 100 plane can be easily determined using this crystallographic orientation, and this direction By using this as the surface, it is possible to obtain a wire drawing die or dresser that has excellent abrasion resistance and is resistant to cleavage. Further, in cases such as drawing high carbon steel wire, it is particularly required that the wire is not affected by heat, and it is essential that the die temperature does not rise.

Since the diamond sintered body according to the present invention has extremely high thermal conductivity, the frictional heat generated in the wire drawing process is quickly transferred to the outside, and the die temperature hardly increases. In addition, in combination with the above-mentioned excellent abrasion resistance, it has particularly good performance as a wire drawing die in this field.

Example 1 The explanation will be based on Figure 4.

A high purity graphite rod for spectroscopic analysis is used as a carbonaceous material with a diameter of 6? ,
It is used as a cylinder 11 with a height of 10W0fL, and its weight is 4
It was 70 mg. As the catalyst metal 13, an Nj-Cr plate (JISl type) with a thickness of 0.1 mm was used, and its weight was 160 m9, and its weight proportion to the whole was 25 Wt%. As the inert metal 12, Au was vacuum-deposited on a Ni--Cr plate to a thickness of 3000 Å and wound around the outer circumference of the graphite cylinder 11 so that the evaporated surface was in contact with the graphite cylinder 11 to prepare the sample structure 10. This was placed in the reaction vessel shown in Figure 2, and the pressure was first raised to 70 kb, followed by rapid heating, and the temperature was increased to point L (1300°C) in Figure 1 in 3 minutes, and then from point L to point M. The temperature rose in 1 minute until it reached 70k.
b●Holded at 1900°C for 10 minutes. Thereafter, the reaction mixture was cooled and the pressure was lowered to atmospheric pressure, and a disk-shaped reactant was recovered. The reactants were tightly bound. When we cut this in the thickness direction and observed the structure after polishing the cross section, we found that diamond crystal grains that grew in the radial direction from the outer periphery toward the center were layered in the thickness direction, as schematically shown in Figure 6. The short axis has a length of 40 to 60μ, the long axis has a length of 100 to 300μ, and they are mutually sintered, so that the catalyst metal used is partially attached to the grain boundaries. was observed. Furthermore, when this reaction product was examined by X-ray diffraction, it was found that all of the graphite used had been converted into diamond. We also discovered that this sintered body has a high degree of crystallographic orientation. That is, X-rays (C
When UKα1) is incident, the obtained X-ray diffraction peak is only the reflection from the 111 plane, and the other planes 220, 311,
The reflection from 40 Maki is the intensity of reflection from 111 surface, which is 100
The number was very low, 2 to 4. In other words, this disk-shaped diamond sintered body has 111 parallel to its smooth surface.
This indicates that it is made up of surfaces. A rectangular sample was cut out from this disc-shaped sintered body, and its thermal conductivity was measured in the direction of diamond growth, and it was found to be 1.9 ca.
The value was 1/Cm・Sec・Deg, which was close to that of type 1a crystal of natural 7 diamond, and the thermal conductivity was effective as a heat sink material. In addition, in order to understand the appropriate quantitative ratio of the catalyst metal, the following two types of experiments A and B were conducted. (4) Ni-C with a thickness of 0.47 Wt as catalyst metal
All conditions were the same as in Example 1 except that an R plate was used.

In this case, the weight proportion of the catalyst metal is 10%.

The state of the obtained disc-shaped reactant is that the catalytic metal is used as a matrix, and elongated diamond particles are observed to have grown within it. It was 30%. The thermal conductivity of this reactant was measured under the same conditions as in Example 1 and found to be 0.
．． 3caI/CwLesec-Deg, and was unsuitable as a heat sink material.

! All experiments were carried out under the same conditions as in Example 1 except that a 10 μm thick Ni-Cr foil was used as the O(B) catalyst metal.

The weight proportion of the catalyst metal in this case is 3.3 wt%.
Unconverted graphite exists in the center of the recovered disc-shaped reactant over an area approximately two diameters apart, and observation of the cross section reveals that graphite remains in the area where diamonds were formed, and the diamond particles are intertwined. It was not sintered. Example 2 As carbonaceous material, diameter 67r$T, thickness 57rrIn
A high-purity graphite disk 7.7゛ for spectroscopic analysis was used.

Permalloy (55Fe-
45N1) Use a disk 8 and coat 1000A of Au on both sides.
A sample structure 6 was prepared, with the structure of the sample arranged as shown in FIG. 3, and placed in a reaction container as shown in FIG. 2. Applying a pressure of 73 kb to such a structure,
The temperature at point L in Figure 1 was raised to 1200°C in 5 minutes, and then to 2000°C at point M in 2 minutes. The temperature and pressure were then lowered in this order to recover a disc-shaped, strongly bonded reactant. When the cross section was observed, it showed the state schematically shown in Figure 5. X-rays Diffraction revealed that all of the graphite had been converted to diamond, and that it had the same orientation as in Example 1.Thermal conductivity in the thickness direction of this disc-shaped sintered body was Measured location 2.
It had a Sec-Deg of 8ca1/Cm, exhibited very good thermal conductivity exceeding the value of type 1a single crystal natural diamond, and was suitable as a heat sink material. Example 3 In order to investigate favorable pressure and temperature conditions, an experiment was conducted under the conditions shown in Table 1.

The materials and configuration used were the same as in Example 1. or,
The temperature was raised to point L in Figure 1 for 2 minutes, then to the target temperature for each experiment in 1 minute, and the holding time was 10 minutes. The symbols in Table 1 are as follows. The O mark indicates a good sintered body in which crystal grains that have grown in a certain direction are sintered together, the 8 mark indicates a sintered body with no directionality of growth, and the X mark indicates a sintered body in which graphite remains.

The eutectic temperature of the Ni-Cr catalyst with carbon is about 1300°C. Example 4 Table 2 was used to examine the effects of the type and quantitative proportion of inert metals.
The experiment shown in was conducted.

A 50p thick Ni foil was used as the catalyst metal. The conditions were the same as in Example 1 except that the heating time from point L to point M in FIG. 1 was 1 min. In Experiment No. 10, no crystal grains growing in a fixed direction were observed.

Among them, Experiment No. 9 showed the best condition. Then numbers 8, 13, 11, 14, 15,
12 came in order. These diamond particles are inferior in crystal alignment compared to No. 9, but the diamond particles exhibit an elongated shape with a ratio of the length of the long axis to the short axis of about 1.5 to 2. The effect was confirmed. Example 5 In order to investigate the wear resistance of this sintered body, 0.2
m! A Ni--Cr disk (JISI type) with a thickness of n was used, and Au was vapor-deposited on both sides to a thickness of 2,000.

All other conditions were the same as in Example 4, and a strongly sintered disk-shaped reactant was recovered. When this material was examined by X-ray diffraction, no graphite was detected, and all of the raw material graphite had been converted to diamond, and it also showed eutectic orientation. From this orientation, the 100 faces of this sintered body are
A wire drawing die was prepared by indexing the 100> direction and making holes in this direction. We conducted a comparative test with a currently commercially available wire drawing die made from a diamond sintered body made by sintering diamond powder with a metal binder mainly composed of CO, and found that it was superior in drawing stainless steel wire. The one made of a sintered body showed about three times the wear resistance compared to the commercially available one.

In addition, when drawing high carbon steel wire containing 0.8% carbon, the die temperature of the commercially available wire was 150°C, whereas the die temperature of the wire according to the present invention was as low as 100°C. We were able to significantly reduce the thermal effects of the wire. Example 6 The following experiment was conducted to investigate the independent effect of the temperature increase rate on the structure of the present sintered body, that is, the alignment and shape of individual crystals.

As the carbon material, 7 mm discs of high purity graphite for spectroscopic analysis with a diameter of 6 and a thickness of 57 m were used. 0.2 as catalyst metal
A Ni-Cr (JISI type) disk 8 with a thickness of T0n was used, and no inert metal was used. A sample structure 6 arranged as shown in FIG. 3 was prepared and housed in a high temperature and high pressure chamber shown in FIG. 2. After applying a pressure of 73 kb to such a structure, the temperature was raised in 5 minutes to 1300'C, which is the temperature at point L in Figure 1, and then to 2200'C, which is the temperature at point M in Figure 1.
The temperature was raised to C under four conditions: 1 minute, 5 minutes, 1 powder, and 3 powder. Finally, the pressure was maintained at 73 kb and the temperature at 2200'C for one powder period, and then the temperature and pressure were lowered in this order. Table 3 shows the results of observing the cross section of the recovered disk-shaped strongly bonded sintered body.

However, the letter n in the table indicates the ratio of the length of the long axis to the short axis of each diamond particle constituting the sintered body.

Before cutting the diamond sintered body and observing its cross section, we measured the thermal conductivity in the thickness direction of the disc.
At room temperature, experiment number 16 was 2.3ca1/Cm
-Sec-0C, experiment number 19 is 1.2c
a1/Cm・Sec・°C was shown.

These values are almost comparable to the values of type 1a single crystal natural diamond. It is understood that the difference between the two values is due to the difference in structure.

[Brief explanation of the drawing]

FIG. 1 shows the diamond synthesis area. Line AB is the thermodynamic equilibrium line between diamond and graphite. line cd
is the eutectic line between the catalyst metal and carbon, and the line in the figure is the Ni-C eutectic line. The shaded area surrounded by EFGH is a pressure and temperature range suitable for the present invention. Fig. 2 shows an example of a configuration diagram of a reaction vessel used in the present invention. 1 is a graphite heater plate 2, 2 is a graphite end plate, 3 is a BN disk, 4 is a BN cylinder plate, and 5 is a graphite heater plate. The reaction chamber is shown. FIG. 3 is an example of a case where the samples described in claim 2 are arranged in a stacked manner. 7,7゛ is a graphite disk, 8 is a catalyst metal disk, 9,9'' is a metal inactive for diamond synthesis,
These components are housed in the reaction chamber 5 shown in FIG. FIG. 4 is an example of a case where the samples described in claim 2 are arranged concentrically. Reference numeral 11 is a graphite cylinder, 12 is a metal inert to diamond synthesis, 13 is a catalyst metal plate, and 10 is a structure of these components, which is housed in the reaction chamber 5 shown in FIG.

Claims (1)

[Claims] 1. In a polycrystalline diamond sintered body containing a catalyst metal for diamond synthesis, each crystal grain of diamond constituting the body has a length ratio of its major axis to its minor axis of at least 2. As described above, the long axis direction of the majority of crystal grains is arranged in a specific direction in the sintered body, and the mutual crystal grains are sintered in the long axis direction, resulting in a substantially continuous A diamond sintered body characterized by forming a diamond phase. 2. A carbonaceous material that is a raw material for diamond and a catalyst metal that is to crystallize diamond are arranged in layers or concentrically, and a metal that is inactive for diamond synthesis is interposed at the interface between the two, and the pressure is 65 Kb or more. The temperature is 20% from the eutectic temperature of the catalyst metal used and carbon.
Bring to high temperature and high pressure conditions defined by three conditions: 0°C higher than the temperature and 100°C lower than the thermodynamic equilibrium line of diamond and graphite, and for a period sufficient for the growth and sintering of diamond crystals. A method for producing a diamond sintered body in which crystal grains are arranged in a specific direction, the method comprising simultaneously converting a carbonaceous material into diamond and sintering it under predetermined pressure and temperature conditions. 3. The metal inactive for diamond synthesis according to claim 2 is Au, Ag, Cu, Pt, Ti, Zr,
Hf, Al, Zn, Sn, Pb, V, Nb, Ta, Mo
, W. 4. Production characterized in that the metal inactive for diamond synthesis according to claim 2 is Au, and its weight percentage is in the range of 0.1 to 5 wt% with respect to the catalyst metal used. Law. 5 When a carbonaceous material that is a raw material for diamond and a catalyst metal from which diamond is to be crystallized are arranged in layers or concentrically and heated at a pressure of 65 Kb or more, the temperature is 200°C higher than the eutectic temperature of the catalyst metal and carbon. Rapid heating is performed at a rate of at least 100°C/min to reach a predetermined temperature between the temperature and the temperature that is 100°C lower than the thermodynamic equilibrium line of diamond and graphite. Diamond sintering with crystal grains arranged in a specific direction is characterized by maintaining the carbonaceous material under predetermined pressure and temperature conditions for a sufficient period of time for growth and sintering, and simultaneously converting the carbonaceous material into diamond and sintering it. Method of manufacturing solids.