JPS59169994A - Growth of diamond crystal - Google Patents

Abstract

PURPOSE:In synthesizing diamonds by ultra-high pressure and high temperature method using seeds grains of diamonds, a solvent metal and carbon, to synthesize diamonds having uniform particle size, by arranging seed diamonds in the carbon or the solvent metal of laminate of them or in their interfacial boundary regularly. CONSTITUTION:Seed grains of diamonds are arranged in a plate of power of graphite as a carbon raw material or a plate or powder of Fe, Co, Ni, Cr, Ta, etc. as a solvent metal of laminate of them or in their interfacial boundary. When graphite and the solvent metal are plates, holes with bottoms are made in the laminate and the seed diamonds are put in them. When graphite and the solvent metal are powder, the seed diamonds are embedded in it. Or, the seed diamonds are arranged between the layers of graphite and the solvent metal and they are reacted at high temperature under high pressure, to synthesize diamonds. Diamonds having small dispersion of particle diameters can be synthesized without controlling pressure and temperature strictly.

Description

[Detailed Description of the Invention] The present invention provides diamond processing under high temperature and high pressure. The first step in synthesizing yuzu is a method of growing crystals using diamond particles. In general, when synthesizing diamonds using the hydrostatic method, it is necessary to control the number of nuclei generated and grow crystals at temperatures and pressures that are close to the sum equilibrium network. This is the key to getting prizes. Therefore, using t-tons for diamond as seeds is an effective means for controlling the number of nuclei that form the center of crystal growth.

Crystal growth methods for synthesizing diamond using the hydrostatic pressure method include a temperature difference growth method and a thin film growth method.

The former is a method in which seeds and non-diamond carbon (hereinafter referred to as raw material carbon) are present with a solvent metal having a temperature difference between them, and the seeds on the low temperature side are grown. The latter is a method in which raw carbon is dissolved through a thin film of solvent metal attached to the periphery of diamond particles serving as seeds, and diamond crystals are grown due to the solubility difference between carbon and diamond. In the thin film growth method, it is possible to generate nuclei during the synthesis without using Miko in advance, but if Miko is used sparingly, the number of nuclei can be easily controlled. However, no matter how much you control the number of nuclei, if you grow diamond crystals in a region with high carbon concentration/supersaturation, you will not be able to obtain good crystals, and the shape of the crystals will be poor. It also contains more impurities such as carbon and air bubbles. In order to reduce the degree of supersaturation, it is necessary to
Must be maintained under pressure conditions. However, in industrial ultra-high pressure synthesis equipment, it is extremely difficult to constantly measure the temperature and pressure in the reaction zone and control them to desired values.

In view of the above circumstances, the present inventors directly adjusted the γ quality and pressure to 1.
From a different perspective, we investigated a method for obtaining diamond-tainted crystals with a high yield and a targeted particle size with a narrow distribution width without the need for tilj control. As a result, if the diamond particles that become the seeds are arranged in a regular manner in a planar or three-dimensional manner, the variation in the conditions for growth that occurs from seed to seed will be reduced, and the microscopic force of 'tJAty, It was found that the variation was reduced and that interference caused by seeds growing too close together was eliminated.

However, with the thin film method, thousands to tens of thousands of seeds can be grown in one layer! Is it necessary to set up a diamond? There are no examples of synthesis.

The present invention was developed based on the above completely new findings.

The present invention will be explained in detail below.

There are various methods for regularly arranging diamond particles that serve as seeds. For example, in the so-called lamination method in which raw carbon and solvent gold 8 or other metals added as necessary to these (hereinafter referred to as solvent materials, etc.) are stacked alternately, holes are regularly punched in the solvent materials, etc., and the seeds are seeded. It's good to embed it. If the solvent substance etc. is in powder or granular form,
If these are mixed and formed into a plate of appropriate thickness, the above method can be applied. In addition, seeds can also be directly press-fitted into the laminated component board. When the laminated material is a metal plate, in addition to mechanical methods, etching methods including photo-etching, electrical discharge machining, laser machining, etc. can be used to fill the holes.

These holes may be through holes, but from the viewpoint of handling the yuzu, it is more convenient if they are not through holes. In order to embed the seeds in the holes, the seeds may be scattered on the laminated component board with the holes drilled and subjected to appropriate vibrations.

In that case, it is desirable that the surface of the seeds be subjected to antistatic treatment. A simple antistatic treatment includes coating or coating with a liquid electrical substance.

There is no particular restriction on the size of the above seeds, but 1i17 and 3
Particles of 0 μ or larger are used. The spacing between the outer sides of Vj and f in a regular arrangement of 1+ children is 100
A value between 1000 it and 1000 it cannot be selected.

If there is a concern that the above-mentioned seeds may come into direct contact with the raw material carbon under high pressure, it is better to set the yuzu to -4 or the like to 3. Gold 4 in this case does not have to be a solvent metal.

In addition, when placing bare seeds in holes sprouted in a solvent metal plate, the openings of the holes are usually closed off with a metal plate or the like after the seeds are placed.

More seeds distributed IP? If the laminated plate to be used is a metal plate without holes, apply a small amount of an adhesive substance to the surface in the form of spots, and adhere bare or metal-covered seeds to the spot. You can also do that. Also, use a net with appropriate openings, or use military or child-prone automatic placement equipment to regularly distribute the items. 2E can be done.

As the above-mentioned solvent metal substance, those which are usually used as a solvent metal in diamond synthesis, such as periodic group 8 materials such as Fe5cO1N1 and Cr s Ta, are used.

The raw material system of the present invention is mainly composed of sushi solvent metal and diamond seeds.
Other gold E is used as a fixing agent to suppress the contact between diamond and carbon, and also to prevent oxygen and nitrogen from entering the diamond.
Moths and the like can be added in an amount of about 50% or less based on the solvent metal. As this metal, M g %'Ca s
T i, Z r % 'V % N b sZn, Y
, Mo, W, Cu, Au, Ag, Si, T3. A+!
! , Ge, In, Sn, Pb, carbide, polide, etc. can be used alone.

In the above reaction system, 1 ft of diamond line growth that can be expected to be produced by the reaction requires 1 seed.
If you decide on the number of miko so that the product of the desired average growth per individual and the number of seeds matches, you can distribute diamonds with the desired particle size! S can be obtained narrowly. In order to systematically know the above expected total growth amount, it is sufficient to perform diamond synthesis with various final loads P and find the growth 4L. In order to obtain a large number of diamond particles, the final load should be increased within the range allowed by the synthesis equipment.However, (if the particle density becomes too high, the grown particles will interfere with each other. In addition, as a method to narrow the particle size distribution width, consider the temperature distribution and pressure distribution of the reaction area, and change the spacing of the seed arrangement in the horizontal and vertical directions, ■) the size of the 1'i seeds, etc. is also valid.

The present invention is effective for any reactants such as raw carbon materials and solvent materials, but is particularly effective for reaction systems where the crystal growth rate is slow.

Next, the entire method according to the present invention will be explained in detail by way of examples.

[Example 1] A reactant was placed in a wax 5 vessel with an inner diameter of 286 mm and a height of 38 mm, with a diameter of 2 a6 rye and a gr7 height of 0.25.
An alloy plate of Fe7O-Ni30 of y:* and a graphite plate of the same diameter and thickness of 1.6 mm were alternately layered 1L' to obtain a reactant τr. The above alloy plate C was engraved with a center spacing of 06 bolts by photo-etching, 0.3
,,,gu×0,25 order 1 (7') hole? Place diamond particles with particle size #120/140 into this hole.
L, above i, '4 +;-7 Both ends of the body were insulated with P graphite plates, further covered with an iron gap, attached to a belt-type ultra-high pressure synthesis device V1, and a pressure of 1 cm was applied, and the reaction section was heated. I turned on the power and directly connected it to IJi+. Reaction conditions are pressure crab 57
Kb, temperature 1σ: estimated to be 1450°C, reaction time 20
It took 2 minutes.

As a result, about 5g of diamond was obtained, but 40% of it was concentrated in the grain size of 410150, and the production rate of good crystals was also lower than that of the conventional method using the same amount of diamonds. This is a two-fold improvement.

[Example 2] Weisen's quick-drying adhesive (trade name: Araldite) was placed on the alloy plate used in the reaction of Example 1 at a center spacing of 0.6 +
Particles coated with N1 to a thickness of 30μ on diamond particles with a particle size of $17(]/200 at every n+a? Diamond was synthesized by the same operation as in Example 1, except for adhesion.The result was almost the same as in Example 1. However, when the amount of adhesion was large, the transparency of the crystal was lost.

[Example 3] Diamond crystals were grown using the same 1·ν゛ζ method as in Example 1, except that in the reaction system of Example 1, holes were placed on the graphite plate. As a result, almost the same results as Fabric Example 1 were obtained, except that the size of the delivered fabric was slightly smaller.

[Example 4] In Example 1 above, the particle size was aimed at 440150,
Shusun decided on the number of kaiiko to match the expected 8gr for this thread. In order to arrange all of these seeds, the thickness of the alloy plate and the graphite plate were set to 0.25 mm and 1.5 mm, respectively.
0 mm, and the spacing between the holes into which seeds are placed was also reduced to 0.6 mm. When this system was subjected to the same operation as in Example 1, the results were as follows:
+7.6 gr, $40/50 Yield: about 50%, good product → 2nd product yielded slightly more than twice as many diamonds as the conventional method.

Exit (11 people, Showa Koko Co., Ltd.)

Claims (2)

[Claims] (1) In a diamond crystal growth method in which non-diamond carbon and a reactant mainly consisting of the solvent Kinsagi and Diamond Miko are provided under pressure and temperature conditions in the diamond stability region, the diamond particles that serve as seeds are grown in a two-dimensional or three-dimensional manner. A method of growing diamond crystals characterized by regular arrangement of diamond crystals. (2) The above-mentioned reactants are made of a laminate of non-diamond carbon and solvent metal stacked alternately, and the diamond particles that become the child are placed in non-diamond carbon waste, in the entire solvent, or in a plane at the interface of these. Alternatively, the method for growing diamond crystals according to Item 1 of the Patent Claim, which is characterized in that diamond crystals are regularly arranged three-dimensionally.