JPS6081095A - Synthesis method of single crystal of artificial beryl - Google Patents

Abstract

PURPOSE:To enable growth of crystal of high quality on the surface of seed by sintering a material for flux on the surface of a seed having the compsn. of beryl. CONSTITUTION:At least one kind of flux material among lithium molybdate, molybdenum trioxide, lithium hydroxide, and vanadium pentoxide is added to a starting material consisting of beryllium oxide, aluminum oxide, and SiO2 having compositional ratio corresponding to beryl, and a single crystal of artificial beryl is synthesized by forming a molten salt by heating the mixture to above the melting temp. of the flux. In this case, one or >= two kinds of the flux material is sintered on the surface of the seed having the compsn. corresponding to beryl and charging it to the molten salt saturated with the starting material, and by producing temp. difference in the molten salt.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for synthesizing artificial beryl single crystals (orthogonal crystal system) using a solvent (flux), and is an efficient and economical method for producing beryl single crystals of better quality than before from molten salt. It is related to a method of synthetic synthesis.

The demand for artificial beryl for use in jewelry parts such as emerald pressure, microwave parts, and other industrial parts has recently been on the rise. Is the molten salt method using a solvent known?The present invention is directed to:
This invention belongs to the improvement of the molten salt method, and particularly relates to the improvement of the method of adding beryl seeds.

The molten salt method uses less energy (heat, pressure) and growth time than the hydrothermal method, and has the advantage of being economical because the equipment and parts used can be greatly simplified. That is, the molten salt method shows the composition ratio of beryl, beryllium oxide, aluminum oxide and silicon dioxide, and optionally chromium oxide (this is an essential coloring agent that is the base color of emerald green when obtaining emerald). (or doping agent) and nickel oxide, iron oxide, cobalt oxide, manganese oxide, or other auxiliary colorant or doping agent, and a solvent such as pentoxide/nadium, trioxide, or
One or more solvents selected from buden, lithium molybdate, lithium hydroxide, etc. are added, and this is heated to a temperature higher than the melting temperature of the above solvent to form a molten salt, and the temperature difference between the molten salt and An artificial beryl (IJ) is formed around the beryl seed crystals placed in the molten salt by either holding it for a long period of time or holding it for a certain period of time and then slowly cooling it with a gentle temperature gradient. In this way, the molten salt method is a method of growing
Although it can be produced or grown in the temperature range of 30°F, in order to grow high-quality beryl single crystals that do not contain inclusions in the crystal, there are many controls such as the temperature profile of the crucible furnace, growth rate, type of solvent, seed quality, etc. There are points to be made. Among these control factors, the most important thing in growing high quality beryl single crystals is to start crystal growth as high as possible on the outermost surface of the seed. However, in artificial single crystal synthesis, the means currently used to initiate high-quality crystal growth are mainly methods of reducing the initial growth rate, and specifically, in the temperature difference method, However, methods have been used to minimize the humidity difference between the growth zone and other parts of the crystal, or to reduce the cooling rate as much as possible when growing crystals by slow cooling. , the temperature difference between the 17-d and the molten salt was 700°C immediately after the beryl seed was added.
Because the temperature is above 0 to 1000°C, microcranks tend to enter the seeds themselves due to thermal shock, and the molten salt on the seed surface is rapidly cooled, resulting in a considerably supersaturated state of the raw material and the initiation of rapid growth. Cracks occur due to internal stress in the crystal, and the molten salt that has entered the cracks is trapped, resulting in feather-like inclusions.

The present invention is intended to solve the above-mentioned problem, and aims to grow high-quality crystals on the surface of the seed by sintering a solvent raw material onto the surface of the beryl composition seed.

The features of the present invention will be described below.

By making the surface temperature of the beryl seeds almost equal to the humidity of the molten salt, it is possible to prevent cracking of the seeds due to rapid heating of the beryl seeds, and to suppress the initial growth rate, thereby making it possible to obtain crystals of good quality. however,
In practice, it is difficult to place seeds into molten salt while maintaining the same temperature as the molten salt.

In the method of the present invention, a solvent layer is sintered on the surface of beryl seeds, and the solvent layer is poured into a molten salt. Then, it takes a certain amount of time for the solvent layer to completely dissolve in the molten salt, and during that dissolution time, the beryl seeds are heated, and when the solvent is completely dissolved, the molten salt around the seeds and the seeds are approximately the same. Because of the high temperature, high-quality crystals can be grown at an early stage. Therefore, it is possible to greatly improve calculation of the crystal that is subsequently grown.

Examples will be described below.

Example 1゜ (1) Raw materials Beryllium oxide 41g Aluminum oxide 5.51i+ Chromium oxide 032 The above raw materials were mixed and sintered.

Silicon dioxide was initially used by cutting 51, and the solvent used was lithium molybdate and molybdenum trioxide 4001 in a 1:1 ratio.

As shown in Figure 1, Beryl Seed 1 is 2 cm square / Thickness 11
Powder 2 with the above solvent composition was placed on each side and sintered at 1400°C for 5 hours. The thickness of the solvent on the 0 seed was 0.5 to 2.
The beryl seeds were added at a heating temperature of 850°C in the seed growth region and 9°C in the raw material holding zone at the time when the seeds were saturated with the raw material in the molten salt having the above solvent composition.
The temperature was 80°C.

As a result, the occurrence of inclusions in beryl single crystals grown on beryl seeds was 115% lower than in the conventional method.
decreased to

Example 2 (1) The raw material was the same as in Example, and the solvent used was 4007 lithium hydroxide, molybdenum trioxide, and vanadium pentoxide in a ratio of 1=1:1.

Next, beryl seed was similarly cut into 1 cm square pieces with a thickness of 1 cm, powder having the above solvent composition was pressed onto both sides of the beryl seed, and pre-sintering was performed at 1400° C. for 1 Qhr. The heating temperature is 900℃ in the growth zone and 925℃ in the raw material zone.
It was set to

By this method, a high-quality beryl single crystal similar to that in Example 1 could be grown.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of beryl seed 1 wrapped in solvent powder 2 and sintered. i 1 concave

Claims (1)

[Claims] Lithium molybdate, molybdenum trioxide, 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. , vanadium pentoxide, etc., and heating this above the melting temperature of the solvent to form a molten salt to synthesize an artificial beryl single crystal. 1 of the above solvent raw materials on the surface of the composition seed.
After sintering the seed or two or more, the raw material is poured into a saturated molten salt and a temperature difference is applied to the molten salt.
A method for synthesizing an artificial beryl single crystal, which comprises synthesizing a beryl single crystal on a beryl seed.