JPH06256007A - Production of hetero diamond and production of sintered material of hetero diamond - Google Patents

Abstract

PURPOSE:To simply produce hetero diamond having both diamond characteristics and cBN characteristics and its sintered material. CONSTITUTION:Diamond particles and cBN particles are subjected to mechanical alloying to produce hetero diamond. The hetero diamond obtained by this method is sintered to produce sintered hetero diamond.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a heterodiamond and a method for producing a sintered heterodiamond. More specifically, it is a substance obtained by substituting a part of carbon of diamond from boron and nitrogen from diamond powder and cBN powder, and has excellent properties of diamond, in particular, properties such as high hardness and high thermal conductivity, and cBN. And a method for safely and productively synthesizing a heterodiamond, which is a substance having both high temperature resistance and the like, and the sintering of various shapes and properties having the above excellent properties from the heterodiamond. And a method for producing a heterodiamond sintered body which is a body.

The heterodiamond and the heterodiamond sintered body produced by the method of the present invention can be used in various kinds of materials such as heat sink members, tool members, structural materials, electronic / electrical equipment members, and other ceramic materials. It can be suitably used in various fields as a useful member or its material.

[0003]

BACKGROUND OF THE INVENTION Diamond is an extremely hard substance, has excellent durability, has extremely high thermal conductivity, and has various outstanding properties such as being a semiconductor. It is used in various material fields including tools such as tools and polishing tools. However, diamond has the drawback of poor resistance at high temperatures, limiting its field of use.

On the other hand, cBN (cubic boron nitride), which is one of the typical ceramics, is inferior in hardness to diamond and is inferior to diamond in other properties, but at an extremely high temperature, for example, 1,200. It has sufficient heat resistance even at about ° C.

Recently, it has the same shape as diamond,
A new substance called heterodiamond, in which part of the carbon of diamond is replaced by boron and nitrogen, has been synthesized and is attracting attention as a new material. Such a hetero diamond is considered to have both the advantages of diamond and the advantages of cBN, and in particular, since it satisfies both high hardness and heat resistance, it is a member of tools such as cutting tools and polishing tools, or a new semiconductor. There are great expectations as a new material in various fields such as materials.

However, in the synthesis of the above-mentioned heterodiamond, heterographite (atom ratio C: B: N = 1: 1 in which part of carbon in graphite is replaced by boron) is used.
By adding copper powder as a catalyst to 1: 1), filling it in a metal cylinder, exploding the explosive in the cylinder, and applying a high pressure of 350,000 atm in a short time of about one millionth of a second. It was reported that heterodiamonds were obtained in a yield of about 30% (Chemical Technology Research Institute newspaper report:
Nikkei Sangyo Shimbun, December 11, 1992).

However, in this manufacturing method, since explosion is used, there is a problem that the danger is high and the equipment cost is high. Further, in such a method, even if the yield is a considerably large value of 30%, only a small amount can be synthesized in one batch, and there is a drawback that the productivity is extremely poor.

The present invention has been made based on the above circumstances.

The first object of the present invention is to solve the above-mentioned problems and to provide a diamond powder and a cBN powder in which a part of the carbon of diamond is replaced with boron and nitrogen. In particular, it is a novel heterodiamond which can be safely and productively obtained as a heterodiamond which is a substance having both properties such as high hardness and high thermal conductivity and excellent properties of cBN, in particular, heat resistance. Moreover, it is to provide a manufacturing method which is remarkably advantageous in practical use.

A second object of the present invention is to suitably produce a heterodiamond sintered body of various shapes and properties having the above-mentioned excellent properties from the heterodiamond obtained by the above novel production method. To provide a method.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the first object. At that time, we focused on the mechanical alloying (MA) method, which has recently been in the limelight as a new manufacturing technique for new metal materials.

The mechanical alloying method is a method of alloying by mechanically pulverizing and mixing raw materials with a ball mill. According to this MA method, the temperature at the time of pulverization or mixing can be freely set, and moreover, in the conventional method that relies on thermal energy such as melting and thermal reaction, it is uniformly solidified due to large differences in specific gravity, melting point, boiling point and the like. Raw materials that were difficult to dissolve or combine can be preferably applied, and new metal materials that could not be obtained by conventional methods or metal materials that were not easily manufactured (for example,
It has become increasingly clear that various intermetallic alloys, intermetallic compounds, oxide dispersion strengthened alloys, amorphous alloys, etc. can be easily produced (for example, NI.
KKEI NEW MATERIALS, 1990, 7
See the 30th of the month).

However, as a result of the investigation, it has been found that there is no example in which the MA method is applied to the production of heterodiamond from diamond.

Therefore, the present inventors have found that diamond and c
From BN, it was examined whether it is possible to synthesize heterodiamond (a substance in which a part of carbon of diamond is replaced with boron and nitrogen) by such an MA method. As a result, it was surprisingly found that the desired heterodiamonds can be obtained by mechanically alloying diamond particles and cBN particles, and at the same time, the method of the present invention using this MA method utilizes conventional explosion. It was also found that it is a practically extremely advantageous method that is safer than the method and is capable of producing a desired heterodiamond with extremely high productivity with very simple equipment.

The present inventors have also found that the heterodiamond thus synthesized can be processed into a sintered body of various shapes and properties, and have established a method for producing the sintered body.

The thus produced heterodiamond and the sintered body thereof have excellent properties of diamond, such as high hardness and high thermal conductivity, and excellent properties of cBN, especially heat resistance. It has also been found that it is a useful material or material that has extremely excellent properties that also have the following properties and can be suitably used in the various fields of application.

The present inventors have completed the present invention based on these findings.

That is, the present invention is a method for producing a heterodiamond which is characterized by mechanically alloying diamond particles and cBN particles.

Further, the present invention is a method which can be particularly suitably applied when processing the heterodiamond from a particulate material to a molding material having a desired shape and property, and the heterosynthesized by the above-mentioned method of the present invention. A method for producing a heterodiamond sintered body, which comprises sintering diamond.

In the method for producing a heterodiamond according to the present invention, a desired heterodiamond is obtained by mechanically alloying diamond particles and cBN particles. According to this mechanical alloying, diamond particles and cBN particles react mechanochemically in the process of co-milling, gradually replacing a part of carbon of diamond with boron and nitrogen, and forming a desired hetero diamond. It has been confirmed by X-ray analysis that it will change. Therefore, according to this manufacturing method,
Not limited to heterodiamonds having an atomic ratio of carbon: boron: nitrogen of 1: 1: 1, heterodiamonds having various atomic ratios can be easily obtained. Depending on the conditions, a heterodiamond composition which is a composition of this heterodiamond and diamond and / or cBN can also be obtained. Such a heterodiamond composition is also regarded as a product produced by the production method of the present invention and can be used for various purposes.

In the method for producing a heterodiamond according to the present invention, the diamond used as a raw material may be natural diamond, various synthetic diamonds, or a mixture thereof in any proportion. These are subjected to mechanical alloying with cBN particles in the form of particles.

The particle size of the diamond particles used for the mechanical alloying is not particularly limited, but is usually 100 μm or less. If this particle size is too large, the time required for the predetermined mechanical alloying becomes long.

As the cBN used as one of the raw materials, various synthetic products can be used, and these are also preliminarily pulverized into particles having an appropriate particle size, if necessary.
It is prepared into particles and then subjected to mechanical alloying with the diamond particles.

In this manufacturing method, the ratio of the diamond particles and the cBN particles to be subjected to mechanical alloying is not particularly limited, but the diamond particles 100
It is suitable to select the cBN particles in an amount of usually 5 to 200 parts by weight, preferably 75 to 150 parts by weight, based on parts by weight.

The carbon in the heterodiamond obtained by appropriately changing this ratio:
It is possible to adjust the atomic ratio of boron: nitrogen, and depending on the mechanical alloying conditions, heterodiamond compositions of various compositions comprising heterodiamond fine particles and diamond and / or cBN fine particles as described above. You can also get Therefore,
The ratio of these diamond particles and cBN particles is not necessarily limited to the above range and may be selected in consideration of the composition of the target product and the conditions of mechanical alloying.

In the manufacturing method of the present invention, the mechanical alloying of the diamond particles and the cBN particles can be easily performed according to a conventional mechanical alloying method such as an apparatus or a method.

For example, a ball mill, a stirring type ball mill, a planetary type ball mill or the like can be preferably used as an apparatus used for this mechanical alloying. With these, the diamond particles and the cBN particles are mechanically co-ground and dispersed and mixed to achieve a predetermined mechanical alloying.

The preferred operating conditions of the above ball mills for suitably achieving this mechanical alloying will be described below.

The crushing force F of particles by the various ball mills can be generally expressed by the following formula (1): F = (1 / W) × n × (m / d) × V ² × t. (1) However, in the formula (1), W is a processing amount (unit: k
g), n is the number of balls (unit: piece), m is the mass of the ball (unit: kg), d is the pot diameter (unit: m), V is the ball speed (unit: m / s), t is the grinding time. (Unit: s).

It is preferable to set the conditions so that the crushing force F is usually 4 × 10 ⁶ (unit: kg · m · s ⁻¹ / kg) or more.

At that time, the velocity V of the ball is 0.4 to
It is selected in the range of 6.0 m / s, and the grinding time t is 3 to
It is preferably about 60 hours.

Here, the ball velocity V can be obtained by the following equation (2).

V = (d × π × R) / 60 (2) where d is the pot diameter (unit;
m), π is the circular constant, R is the rotation speed of the ball mill (unit:
r. p. m. ).

The mechanical alloying by crushing and mixing is preferably performed so that the particle size of the crushed and mixed product is as fine as possible. Specifically, for example, the particle size is 0.05. -10 μm, especially 0.0
It is preferable that the treatment is performed within a range of 5 to 5 μm.

As described above, the diamond particles and c
By mixing the BN particles while co-milling, a predetermined mechanical alloying can be suitably achieved, and a desired heterodiamond can be easily obtained with high productivity.

The heterodiamond according to the manufacturing method of the present invention is obtained as fine particles as described above. Depending on the application, this heterodiamond can be used in the form of fine particles as it is, but it can be easily molded into a molded product of the desired shape and properties, and is widely used as a molded product suitable for various applications. can do.

As a method of forming the heterodiamond fine particles into a compact, for example, a method of sintering the heterodiamond fine particles to form a sintered body, that is, a method for producing the heterodiamond sintered body of the present invention can be preferably adopted.

The method for producing the heterodiamond sintered body of the present invention will be described below.

The sintered body can be manufactured by various known sintering methods as long as the heterodiamond obtained by the manufacturing method of the present invention is used as the sintering raw material.

The above-mentioned heterodiamond used as a raw material for producing the sintered body usually has a particle size of 10 μm or less, preferably 5 μm or less. Therefore, it is usually preferable to use the heterodiamond fine particles obtained by the production method of the present invention as it is as a raw material for producing the sintered body.

If desired, other components may be added to the above-mentioned heterodiamond fine particles and used as a raw material for producing a sintered body.

The production of a heterodiamond sintered body from the above-mentioned raw material fine particles is carried out by various known techniques for producing a sintered body, for example, a hot pressing method (HP method), a hot isostatic pressing method (HIP method), a cold still method. It can be easily performed by a usual method such as a hydraulic pressurizing method (CIP method). At that time, after preforming the raw material fine particles by compression and pressure in advance,
It may be sintered at a predetermined temperature, or may be molded by directly sintering the fine particles under compression and pressure, or various techniques may be applied depending on the case.

The sintering temperature is usually 1,000 to 1,80.
It is preferable to select in the range of 0 ° C.

The pressure applied during sintering or the pressure applied during preforming is usually from atmospheric pressure to 3,000 kg /
It is preferable to appropriately select from the range of cm ² .

The sintering time is usually about 10 minutes to 1 hour.

As described above, the desired heterodiamond sintered body having various desired shapes and properties can be suitably produced from the heterodiamond obtained by the production method of the present invention.

The thus obtained heterodiamond and the sintered body of heterodiamond have excellent properties of diamond, particularly, properties such as high hardness and high thermal conductivity, and cBN.
Since it has the excellent properties of, especially heat resistance and the like, for example, heat sink members, tool members,
It can be suitably used in various fields as various useful members such as structural materials, members for electronic / electrical devices or other ceramic materials, or materials thereof.

[0048]

The present invention will be described in more detail below with reference to examples of the present invention, but the present invention is not limited to these examples.

Example 1 500 g of diamond particles having a particle size of 5 to 12 μm and 500 g of cBN particles having a particle size of 20 to 50 μm were charged into a planetary ball mill, and 50 spherical balls made of SUS304 and having a diameter of 10 mm were used. It was used and mechanically alloyed by co-milling for 10 hours with the ball mill to obtain a product having a particle size of about 0.05 to 2 μm.

When X-ray diffraction analysis was performed on this product, as shown in Table 1, it was confirmed that a desired heterodiamond having a structure in which part of carbon was replaced by boron and nitrogen was formed. Was done.

In Table 1, for comparison, the raw material particle mixture (diamond particles and c
The X-ray analysis results for an equal weight mixture with BN particles) are also shown.

[0052]

[Table 1]

(Example 2) The heterodiamond fine particles as the co-ground product obtained in Example 1 were treated at a treatment temperature of 1,
Under the conditions of 350 ° C., treatment pressure of 10 atm, and treatment time of 2 hours, HIP treatment and sintering were performed to obtain a desired heterodiamond sintered body.

This sintered body has a thermal conductivity of 7 W / (cm ·
K), which is extremely high, and the oxidation initiation temperature in air is 1,400 ° C., which is extremely high, and it has been found to have the advantages of diamond and cBN.

[0055]

INDUSTRIAL APPLICABILITY In the method for producing a heterodiamond according to the present invention, the diamond particles and the cBN particles are mechanically alloyed by co-pulverizing them with a ball mill or the like, rather than the conventional method utilizing explosion. Since a desired heterodiamond in which a part of carbon is substituted with boron and nitrogen is synthesized, excellent properties of this diamond, particularly properties such as high hardness and high thermal conductivity, and excellent properties of cBN, especially, Heterodiamond, which is a material that has properties such as heat resistance, can be obtained safely and with high productivity using simple equipment.

Further, in the method for producing a heterodiamond sintered body of the present invention, since the heterodiamond obtained by the above-mentioned excellent production method of the present invention is used as a raw material for production, a heterodiamond sintered body having various shapes and properties is obtained. Can be produced in large quantities and advantageously.

That is, according to the present invention, it is possible to provide a novel and practically advantageous method for producing a heterodiamond and an advantageous method for producing a sintered body thereof.

Claims (2)

[Claims] 1. A method for producing a heterodiamond, which comprises mechanically alloying diamond particles and cBN particles. 2. A method for producing a heterodiamond sintered body, which comprises sintering the heterodiamond produced by the method according to claim 1.