JPS6086099A - Synthesis of artificial beryl single crystal - Google Patents

Abstract

PURPOSE:In the titled synthesis by fused salt method using a solvent, to obtain high-quality beryl single crystal efficiently, by carrying out the use of raw material substance and temperature control more accurately, regulating crystal growth rate. CONSTITUTION:A raw material substance showing almost beryl composition, comprising BeO, Al2O3, SiO2, and, if necessary, Cr oxide, and other colorant, is mixed with one or more of lithium molybdate, MoO3, LiOH, V2O5, etc. as a solvent. The mixture is heated at >= the melting temperature of the solvent, a fused salt is formed to synthesize or to grow artificial beryl single crystal. In order to regulate crystal growth rate, lithium molybdate is premixed with MoO3 in powder to give a fused salt, one or more of the raw material substances are sintered or made into glass to give a raw material substance, and the fused salt, the raw material substance and quartz are used. Further the crucible 5 is divided by the buffle 7 into the seed crystal growth zone 12 and the zone 13 of the raw material and quartz, temperature is controlled in each zone, an amount of dissolution is regulated, and an amount of transportation of the raw material substance to the zone 12 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method (molten salt method) for synthesizing an artificial beryl single crystal (hexagonal system) using a solvent (flux).

<Conventional technology> The molten salt method uses less energy (heat) than the hydrothermal method.

In other words, the molten salt method exhibits the beryl composition ratio. Beryllium oxide, aluminum oxide, silicon dioxide, optionally chromium oxide (this is an essential coloring agent or doping agent that provides the emerald green base color when obtaining emeralds) and nickel oxide, iron oxide, cobalt oxide, oxide Adding one or more solvents selected from panadium pentoxide, molybdenum trioxide, lithium molybdate, lithium hydroxide, etc. as a solvent to a raw material consisting of manganese and other auxiliary colorants or doping agents. , to form a molten salt by heating it to a temperature higher than the melting temperature of the above solvent, and to hold this molten salt for a long period of time with a temperature difference, or to cool it slowly with a gentle temperature gradient after holding it for a certain period of time. This is a method in which beryl seed crystals are placed in molten salt in one of the operations, and artificial beryl is generated or grown around the seed crystals.

<Objective of the Invention> The object of the present invention is to efficiently and economically synthesize high-quality beryl single crystals by controlling the crystal growth speed.

Beryl single crystals synthesized by conventional methods tend to contain feather inclusions and microcrystals such as zenasite during the growth process, which reduces appearance quality and yield.

Prevents the generation of microcrystals such as feather inclusions and zenasite. To achieve this, the current growth methods (use of raw materials, temperature control, etc.) must be more precisely controlled to control the crystal growth speed. However, the current methods are insufficient.

<Summary of the Invention> In particular, the present invention uses raw materials (beryllium oxide, aluminum oxide) that have been vitrified or sintered in advance in order to control the crystal growth speed.

In addition to using silicon dioxide, chromium oxide, etc. as a coloring agent, and quartz, the inside of the crucible is further divided into two with a buckle, and divided into a seed crystal growth zone and a raw material 1 quartz dissolution zone, and the temperature of both zones is controlled. This method is characterized in that it not only controls the amount of dissolution, but also controls the transportation of raw materials to the seed crystal zone.

<Example 1> (1) Raw material beryllium oxide 4. I P , aluminum oxide 5,
51. Weigh 0.31 of chromium oxide to create a mixed powder. Next, this mixed powder is mixed and pulverized using a ball mill for 5 hours or more. In this case, the material of the pot and ball is a sintered material of high purity alumina. Next, this mixed powder is compacted into a spherical shape and sintered. Silicon dioxide was initially used by cutting 52 pieces of quartz. After that, add 2f per week.

(2) Solvent Next, as 7 lacs, 40Of lithium molybdate and molybdenum trioxide were weighed and mixed in a 1:1 ratio.

(3) Equipment A platinum crucible was used as a container for charging the above substances.

For heating, the apparatus shown in FIG. 1 was used. ■ is a heating device,
■ is a heating heater, ■ is a measurement terminal of a thermocouple thermometer that controls the heater, and controls the temperature of each heater. ■ is a baffle that partitions the inside of the crucible.

(4) Method: Put the solvent powder into a platinum crucible and set the temperature of the heating device to 890℃.
Set to ℃ and dissolve. Next, sintered bodies (beryllium oxide, aluminum oxide, chromium oxide) are placed at the bottom of the 0 zone, and quartz pieces are placed at the top. Next, the set temperature of the heating device is changed to 850° C. for the @ zone (seed crystal growth zone) and 890° C. for the 0 zone (raw material 1 quartz zone).

Once it is in the growing state, put the seed crystal in the [phase] zone. The surface of the seed crystal used is a polished surface.

(5) As a result, we were able to maintain the seed crystal growth speed constant for a long time, reducing the occurrence of inclusions in the grown beryl single crystals, reducing the cost of Ar, which has a low growth temperature, and shortening the heater life. Long-lasting effects were obtained.

<Example 2> (1) Raw materials Same as Example 1 (2) Solvent As a flux, 4002 powders of lithium molybdate and molybdenum trioxide are weighed and mixed at a ratio of 1:1.2.

(3) Apparatus Same as Example 1 (4) Method Same as Example 1 (5) Results The seed crystal growth speed could be kept constant for a long time and the occurrence of inclusions in the grown beryl single crystal could be reduced. . In addition, since the growth temperature is low, the cost of the furnace can be reduced and the life of the heater can be extended.

<Example 3> (Same raw materials as Example 1) (2) As a solvent flux, 4002 powders of lithium molybdate and molybdenum trioxide were weighed and mixed at a ratio of 1:0.8.

(3) Apparatus Same as Example 1 (4) Method Same as Example 1 (5) Results The seed crystal growth speed could be kept constant for a long time and the occurrence of inclusions in the grown beryl single crystal could be reduced. . Furthermore, the cost of Ar, which has a low growth temperature, can be reduced and the life of the heater can be extended.

<Effects of the Invention> As explained in the above embodiments, the effects of the present invention are that, while securing the essential benefits of the conventional molten salt method, it is possible to improve quality and yield, and to achieve significant improvements. The present invention is extremely useful as a method for synthesizing artificial beryl single crystals because it can reduce costs.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main components of the heating device according to the present invention, FIG. 1 (α) is a top view of the device, and FIG. 1 Cb) is a front view of the device. ■・・・Heating device■・・・Lid of heating device■・・・Heater■・・・Measuring terminal of heat n vs. warming needle■・・・・・・
Platinum crucible ■・・・Thermocouple terminal for measuring molten salt■・・・・・・
Baffle ■... Molten salt (flux) ■... Quartz piece [phase]... Raw material @... Seed crystal 0... Seed Crystal growth zone 0...Raw material 1 quartz zone or above Applicant Suwa Seikosha Co., Ltd. Agent Patent attorney Tsutomu Mogami

Claims (1)

[Claims] Lithium molybdate, molybdenum dioxide, lithium hydroxide as a solvent to a raw material obtained by adding beryl oxide, aluminum oxide, silicon dioxide and, if necessary, chromium oxide and other coloring agents. In a method of synthesizing or growing an artificial beryl single crystal by adding one or more selected from vanadium pentoxide, etc., and heating this above the melting temperature of the solvent to form a molten salt, One or more of the above raw materials are sintered or vitrified in advance in a molten salt made by mixing two of the above solvents, lithium molybdate and molybdenum trioxide, in powder form, and the two are mixed with a baffle. 1. A method for synthesizing an artificial beryl single crystal by a molten salt method, characterized in that beryl single crystals are synthesized or grown by placing the beryl single crystals in a container partitioned into two compartments and creating a temperature difference.