JPS60260495A - Preparation of single crystal of chrysoberyl - Google Patents

Abstract

PURPOSE:To prepare a large crystal of chrosoberyl easily by forming a molten zone in the starting materials prepd. previously from a powder mixture of Be oxide and Al oxide to a rod at high temp. obtd. by converging infrared rays, and shifting the molten zone. CONSTITUTION:A halogen lamp 4 is placed at one focus of an ellipsoidal mirror of revolution 3, and a rod-shaped starting material 5 prepd. by sintering a mixture consisting of at least Be oxide, Al oxide, and Cr oxide as colorant at >=800 deg.C is placed at another focus. The starting material 5 is supported by an upper revolutional shaft 6 and a lower revolutional shaft 7. The shafts 6, 7 are sealed tightly in a transparent quartz tube 8 and the atmosphere in the tube is adjusted optionally. It is also possible to evacuate or to compress the atmosphere. Only the temp. of the part of the strating material 5 placed at the position coinciding completely to the position of the foci can be elevated to form a molten zone 9. The molten zone 9 is shifted on the starting material rod by the vertical movement of the shaft 6, 7. In this case, the temp. of the molten zone 9 is held at >=1,870 deg.C, the proportion by wt% of Be oxide to Al oxide in the molten zone is regulated to (25-15)/(75-85), and the proportion by weight of the Cr oxide basing on the total weight of the Be oxide and the Al oxide is regulated to 1.54-3.00wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves forming a melt zone by focusing infrared light on a raw material made of a mixed powder of hiberllium acid and aluminum oxide molded into a rod shape, and then moving the melt zone. This invention relates to a method for converting crinberyl single crystals.

An object of the present invention is to easily obtain large-sized culinberyl single crystals.

Another object of the present invention is to obtain criberyl single crystals at low cost.

Crimperyl has a composition of B e A t204 and is famous for its gemstones such as cat's eye stone and alexandrite. The samples to be manufactured are pbo, pbo-pbF2 system, P
b0-PbF, -B, o3 series, Li, MOO, ~MOO
.

A number of methods have been used to use fluxes such as Fibers and other fluxes. However, it is difficult to obtain large crystals using these methods, and crystals produced by such methods tend to form twin crystals, making it difficult to produce single crystals.

The W of the present invention is that the high temperature obtained by concentrating infrared rays forms a complete melting zone in the raw material that has been formed into a rod shape in advance, and that by moving the melting zone, the criberyl single crystal can be easily submerged. I found it.

FIG. 1 shows a state diagram of the BeOA 403 system.

As is clear from the figure, the weight ratio of At203 is high from 75 inches to 85 inches.
There is a region where 3 and melt coexist. Even if it is simply cooled and solidified from this region, 5 B eO, A 403 or B
ed.

Only mixed crystals of 3 At2 o3, BeO, and At203 are produced, and single crystals of Bed and At203 are not obtained. However, by using the method of the present invention, criberyl single crystals were easily obtained.

The principle of the invention is shown in FIG.

A melting zone 2 is formed on the rod-shaped raw material 1 by infrared IRK.2 From the composition of the melting zone 2, the weight ratio of At and oB is 75%.
Assume that it is between 85 and 85 cm. The temperature of the molten zone is 1870
If the temperature is maintained above ℃ and the molten zone is moved upward in the raw material frame, the lower Hia of the molten zone becomes 7℃ or less, and BeO, A
A region where t20g and melt coexist is generated. In this region, Bed and t20° remain in the lower raw material, and since the melt moves upward together with the melt f, B in the lower raw material.
@O, *zl Only the o3 single crystal remains Lower raw material rod, that is, the region where Be0-At203 grows K B e
The presence of O, A 1203 seed crystals facilitates crystallization, and a perfect single crystal is produced.

In addition, chromium oxide is used as an eyebrow coloring agent to precipitate the green color of the Crimberyl single crystal. Chromium oxide has a heavy electric ratio of 1 to the total weight of beryllium and aluminum oxide.
．． 54~AOQ4 is mixed.

Referring to FIG. 6, a device fK for implementing the present invention will be described.

A logen lamp 4 or a xenon lamp is placed at one focal point within the spheroidal bell body 3, and a rod-shaped raw material 5 is placed at the other focal point. The rod-shaped raw material 5 is attached to the upper rotating shaft 6. It is supported by a lower rotating shaft 7. The raw material rod 5 and the rotation @6.7 are sealed in a transparent quartz tube 8, and the atmosphere can be freely controlled, and it is also possible to use vacuum or pressurization. Only the part that completely coincides with the focal point is the molten zone.The molten zone 9 can be moved over the rod-shaped raw material by moving the rotating shaft 6.7 up and down.

By using the method of the present invention, it is possible to produce large-sized perfect crimperyl single crystals without twins.

The present invention will be described below with reference to embodiments.

Example 1 Beryllium oxide powder 252, comma alumina powder 751
After mixing chromium oxide powder in a 3V full ball mill, the mixture was compression molded into a rod shape and fired at 120uC. This raw material rod was set in an infrared central heating furnace, and the melting zone was set at 5' for 1 hour/hour.
All dark green alexandrite crystals are moved at a speed of 7 tons.

Example 2 From beryllium oxide, acid ratio aluminum, and chromium oxide,
Only the bulky part of the raw material rod that will become the molten zone is made of 80 parts aluminum oxide and 20 parts beryllium thioxide, and is set on the upper rotating shaft, and a single molecule crimperyl single crystal is set on the lower rotating shaft; The rotating shaft and the lower rotating shaft were rotated in opposite directions, and after a molten zone was formed, the seed crystals were brought into contact and the molten zone was moved four times. With this method, diameter 10j + ac length 8
Example 6 where alexandrite crystals of crn were obtained Aluminum oxide 60F, beryllium oxide A'5P, chromium oxide 11P, titanium d oxide α5? Mix in a ball mill, 8
After hot press molding at 00℃ and 30 Kz/-J into a rod shape, it was set in an infrared concentrated heating device and heated at 4K4
Crystal growth was carried out under an RGL cumulative pressure of /l:ml to obtain criberyl with cat's eye-shaped striations.

In the present invention, the sintering temperature of the raw material rod is set to 800°C or higher, but if the sintering temperature is lower than 800°C, air bubbles may remain in the synthesized single crystal, which significantly impairs optical properties and saturation. deteriorate. Chromium oxide V' added as a coloring agent
i 1 of the total weight of beryllium oxide and aluminum oxide.
Addition amounts of 54 to 500% will reduce the amount of chromium oxide added, but if the amount exceeds 500%, segregation of chromium oxide will occur, resulting in cracks in the single crystal.
- Also, if the amount is less than 1.54 degrees, sufficient coloring cannot be obtained.

According to the present invention, a large single crystal with uniform material and uniform coloration was provided, and a crimberyl single crystal which was excellent both optically and decoratively was obtained.

[Brief explanation of the drawing]

FIG. 1 is a detailed state diagram illustrating the present invention. The second south is a diagram explaining the invention in detail, $3 Figure V'
FIG. 2 is an explanatory diagram of an infrared concentrated heating device used in i-hontakumei. 1... Rod-shaped raw material 2... Melting zone 6... Spheroidal mirror body 4... Logen lamp 5.
...Rod-shaped raw material 6...Upper rotating shaft 7...Lower rotating shaft 8...Transparent quartz tube? ... Melting zone or above Applicant: Suwa 1' ILT-sha Co., Ltd.

Claims (1)

[Claims] In addition, the upper rotating shaft and lower rotating shaft can move up and down, and the above-mentioned upper rotating shaft 1
In a single crystal manufacturing method using an infrared, gravel-concentrated heating furnace with a 11k enclosing and sealed quartz arm, and a heating lamp consisting of a halogen lamp or a halogen lamp, at least 111J um, aluminum oxide and oxidized A rod-shaped raw material is formed by mixing chromium and sintering at 800°C or higher, and the above-mentioned
Place a heating lamp, fix the material between the rotating shafts on the VCC front ball so that the rod-shaped raw material is placed at the other focal point, and use the infrared rays of the heat lamp to place the rod-shaped raw material in the front R8 rod-shaped raw material. While forming four melting holes, the rod-shaped raw material is
The molten zone is moved along the rod-shaped raw material described in -II by moving, and at the same time a single crystal is formed at the lower part of the molten zone, and the molten temperature is V'11870°C or higher,
and the mixing ratio of the beryllium oxide and the aluminum oxide in the melting zone is 25 to 15% by weight of beryllium oxide and 75 to 85% by weight of acid hyaluminum, and the chromium oxide is a mixture of beryllium oxide and acid hyaluminum. 1.54 to 3.00% by weight based on the total weight of Crimberyl single crystal.