JPS58181788A - Manufacture of crystal - Google Patents

Abstract

PURPOSE:To simply attain high temp. and pressure and to obtain a high purity crystal, by enclosing a starting material for the crystal with a prescribed wrapping material and by heating only the starting material by a prescribed means. CONSTITUTION:A starting material for a crystal is enclosed in a wrapping material with optical transparency or magnetic permeability. The enclosed starting material is melted by heating with laser light or induction heating from the outside, and the molten material is slowly cooled. Thus, only the starting material is melted by heating, high temp. and pressure are simply attained, and a high purity crystal is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing crystals, and relates to a method for producing crystals at low cost when producing materials that require ultra-high temperature and high pressure conditions, such as gemstones and metal crystals such as diamond. The present invention provides a method for manufacturing.

Traditional methods for producing single crystals can be roughly divided into (1) flame melting method, (2) hydrothermal synthesis method, (3) flux method, (4) Czochralski method, (5) zone melting method, etc. are known.

The flame melting method is a method in which a powder with a composition similar to sapphire or ruby falls into the flame of a gas burner and is heated with a gas burner, but this method requires high-purity raw materials. However, very good quality crystals were not obtained.

In the hydrothermal synthesis method, for example, when making a ruby, approximately 2
Under a pressure of 0oO atmosphere, 1-2N Na2CO3 or 0.5N NaOH dissolved in water, 80-90%, and α-alumina (0.18/l sodium chromate).
This is a method in which ruby seed crystals are filled and the crystals are grown at a growth rate of about 0.05 to 0.25 degrees, but the equipment is large-scale and the production efficiency is very low.

In the flux method, for example, equal amounts of Namal oxide and Namal fluoride are added as a flux, aluminum oxide is added therein, and the mixture is heated to about 1260°C and melted to form a 0.1
In this method, pink ruby crystals are produced by precipitating the crystals of 1 to 1b and further immersing them in sodium chromate. However, with this method, the flux decreases and the composition changes, and the viscosity changes and the composition fluctuates dramatically1. In the Czochralski method, the raw material is melted in a crucible, and the material is dipped on a seed crystal and then pulled. In the zone melting method, raw materials are formed into a rond shape,
The method of producing single crystals by partially heating and recrystallizing them using induction heating and moving the molten zone has been developed in 11] for the production of single crystals of Sl. No method has been developed to produce it at high pressure.

Therefore, both methods are suitable for high-temperature, diamond-like
It was not useful for producing crystals requiring high pressure.

For example, when synthesizing diamonds, the atmospheric pressure is 20oo
℃ or higher is required, but it is extremely difficult to maintain this condition for a certain period of time. Therefore, in some areas, iron and
Nickel 1. Although it is manufactured using a method using catalysts such as germanium/nickel or nickel/chromium, it still operates at a pressure of 30,000 to 60,000 atm.

Manufacturing equipment that requires conditions of 1000°C or higher and can withstand high temperatures and high pressures has a limit of filling about 102 raw materials at a time, and can only produce crystals with about one cavity. Moreover, the equipment was also very large-scale.

In view of the above-mentioned drawbacks of the conventional methods, an object of the present invention is to provide a high-pressure, high-temperature crystal manufacturing method that is extremely simple and energy-saving.

Hereinafter, it will be explained in detail using the drawings. For example, as shown in FIG. 1, a crystal raw material 1 is enclosed in a transparent material sphere (for example, quartz, glass, etc.) that becomes an outer packaging material 2. As shown in FIG. Next, a CO2 laser focused from the outside or Y
When the crystalline raw material 1 serving as a core is heated and melted by an AG laser 3 or the like, the crystalline raw material 1 serving as a core is heated and expanded, but on the other hand, the outer material is not directly heated and is heated. It also has poor conductivity, so it rarely heats up or expands, except in the vicinity where it is in contact with crystalline materials. In other words, the crystal material 1 is maintained at high temperature and high pressure for a certain period of time. Thereafter, when the power of the laser 3 is gradually reduced and the raw material 1 is slowly cooled, the raw material 1 is gradually cooled under high temperature and high pressure, and crystals are formed. In addition, at this time, the outer packaging material 2
is heated very little, so it cannot be melted or destroyed. Finally, the outer packaging material 2 is removed and the crystals are taken out.

For example, when manufacturing diamonds, conditions of 300,000 atmospheres and 30,000 degrees are required.
Graphite 1Qiii', which has been press-molded into a spherical shape, is covered with powdered glass, and the whole is heated. Alternatively, graphite may be inserted into pre-molten glass and allowed to cool and harden.In this case, since the diameter of graphite is 2 crn, the diameter of the outer envelope made of transparent glass should be 20 cm or more. Suppose that this sphere has a power of 1
When the YAG laser 3 of o○○W is focused and the graphite nucleus is externally heated for about 10 minutes, the graphite becomes
Heated and melted at 5000°C or higher. Furthermore, at this time,
Since the outer packaging material 2 is made of glass, it has poor heat conduction.
On the order of a few minutes, no thermal expansion occurs on the outside of the sphere. Also,
If the glass diameter is 20 cm or more (approximately 10 times) compared to the graphite diameter of 2 m, even if the internal pressure is 500,000 atm, the pressure on the glass bulb surface will be about 600 atm, and the Young's modulus of the glass, 6~8 x 10 Af
//Considering cM, it will not be destroyed. Next, reduce the power one by one and cool it to about 3000℃.
Then, upon rapid cooling, a diamond is obtained.

As another method, if a magnetically permeable material such as AZ 203 porcelain is used as the outer packaging material in the above embodiment,
As shown in FIG. 2, only the crystal raw material is heated, melted, slowly cooled, and crystallized using a high-frequency induction heating coil 4 from outside the outer packaging material. This method is only possible if the crystalline material is an electrical conductor.

As described above, the method of the present invention heats and melts only the crystal material, so it is a very energy-saving crystal manufacturing method.Moreover, the outer packaging material is hardly heated, so it does not require much heat intensity. It is not necessary to use necessary materials and can be easily manufactured. Further, since the crystalline material is melted and heated in the solid outer packaging material, a high temperature and high pressure state can be obtained relatively easily through self-expansion. At this time, if the crystalline raw material serving as the core is made porous to some extent during pressure molding, pressure adjustment will be easier. It is also clear that crystals can be obtained at lower temperatures if a catalyst or the like is mixed into the raw material for crystallization.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a method of heating a crystal raw material with a laser according to one embodiment of the present invention, and FIG. 2 is a diagram showing a method of heating a crystal raw material with high-frequency induction heating according to another embodiment of the present invention. It is. 1...Crystal raw material, 2...Outer packaging material,
3... Laser, 4... High frequency induction heating coil. Name of agent Patent attorney Toshio Nakao and 1 other person Commissioner of the Japan Patent Office 1 Display of the case 1986 Patent Application No. 63744 2 Name of the invention Crystal manufacturing method 3 Interaction with the person making the amendment Patent application Address 1006 Kadoma, Kadoma City, Osaka Prefecture Name Name
(582) Matsushita Electric Industrial Co., Ltd. Representative Yama
Toshihiko Shimo 4 Agent 571 Address 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (1) [Power 1000] on page 6, lines 6 to 6 of the statement
WJ'ir/: ヮ-10KW Corrected to J. (2) "About 10 minutes" on page 6, line 7 of the same book has been corrected to "about several minutes." (3) r5000tl on page C, line 8 of the same book: J'1r3
000℃”.

Claims (3)

[Claims] (1) A method for producing crystals, which comprises heating, melting, and slowly cooling a crystalline raw material surrounded by an outer envelope material having predetermined characteristics mainly from outside the outer envelope material. (2) The crystal manufacturing method according to claim 1, characterized in that the outer envelope material is an optically transparent substance and a laser beam is used as the heating method. (3) The crystal manufacturing method according to claim 1, wherein the outer packaging material is a magnetically permeable material, the crystal raw material is a single conductor, and the heating method is an induction heating method.