JPS60176985A - Preparation of raw material for growing single crystal - Google Patents

Abstract

PURPOSE:To prepare the titled raw material providing single crystal containing no cells, by treating melt of raw material powder at high temperature under vacuum. CONSTITUTION:Melt of raw material powder such as Al2O3, BeO, etc. is treated at 10<-1>-10<-5>Torr vacuum at 800-1,500 deg.C to remove cells. The raw material is uniformly blended with a colorant such as CrO3, Fe2O3, etc., packed into a rubber tube, pressed by rubber, sintered, and formed into a rod. Then, this raw material rod is hung from the upper shaft of a single crystal production unit of infrared heating, and seed crystal is set on the lower shaft, they are heated, melt is formed between the raw material and the seed, both of them are moved downward a simultaneously at <=3.0mm./H, to grow single crystal on the seed crystal. Consequently, single crystal useful as artificial jewel, electronic material, etc. containing no cells, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention is a raw material manufacturing method for growing a single crystal by a floating zone method using alumina (Atiss) and beryllia (BO2) as raw materials.

[Prior art]

Until now, most of the patents for the floating zone method (hereinafter referred to as FZ method) were related to new crystal growth methods, and there were almost no patents related to the quality of the crystals, and the crystals grown by these methods had many defects. In particular, air bubbles, which are one of the defects in artificial crystals used as jewelry, are a major cause of reducing the original reflection and refraction of light, reducing the value of the crystal as a jewelry.

〔the purpose〕

The present invention solves the above problems, and its purpose is to produce a raw material for synthesizing corundum crystals and alexandrite crystals without air bubbles, which are grown by the Ii'Z method. The purpose is to provide a method.

〔overview〕

The present invention is a method for growing a single crystal from a melt, and is characterized by treating raw material powders of corundum crystals and alexandrite crystals in a vacuum.

Alumina used in the present invention includes α-alumina, r-alumina, etc., but is not limited thereto.

The same is true for beryllia.

The optimum treatment temperature in the present invention is in the range of 800° C. to 1500° C. If it is below 800° C., dissociation and desorption of the adsorbed gas are difficult to occur and the effect is small. At temperatures above 1,500°C, secondary particles are formed, the particle size increases, and sinterability deteriorates.
'Torr ~ 1O-6TOrr is optimal, and 10-1
Below TOrr, there is no effect in removing adsorbed gas, and 10
-'Torr or more, no change is observed in the removal of adsorbed gas, and the effect is the same. Therefore, the above range is desirable.

The raw material to be treated in the present invention is used for single crystal growth by the FZ method. In the case of corundum crystals, alumina is the main raw material, and as a coloring agent, chromium oxide for ruby, chromium oxide and nickel oxide for padparadsia, iron oxide and titanium oxide for px-sapphire, and the raw material is sintered into a round rod shape. However, by using the above-mentioned processing raw materials, bubble-free crystals can be synthesized without affecting the type and amount of these colorants.

In the case of alexandrite crystals, the above-mentioned processing raw materials alumina and beryllia are similarly used, chromium oxide and iron oxide are added as colorants, and the crystals are grown by the FZ method using the raw material rods formed. Bubble-free crystals can be synthesized without any effects.

J Toryo in the present invention adds the above-mentioned coloring agent, mixes well, packs into a rubber tube, performs a rubber press, and then sinters in an electric furnace to obtain a length of 10 mm and a diameter of 8 to 10 mm.
Form into a bar shape of y++m. So this field, the fee is F.
It is suspended from the upper shaft of the Z equipment (infrared heating single crystal production equipment), and the seed crystal is placed on the lower shaft to perform heating, forming a molten body between the raw material and the seed, and simultaneously heating both at a constant speed. to grow the crystal on the pusher crystal.

, the downward movement speed, that is, the growth speed at this time, is 50 mm.
/ H or higher, air bubbles are included in the crystal, and 3
．． Desirably less than 0 exposure/H.

[Example 1] Reagent grade (999% or higher purity) α-alumina 40r was placed in a platinum crucible and treated in a vacuum sintering furnace at a temperature of 1500°C and a vacuum level of 10 Torr for 2 hours.The raw material was oxidized at 3 wt%. Add chromium, add Diflon in milk needle and mix well. After drying, 20r of the mixture was packed into a rubber tube with an inner diameter of 101rfn, one end was sealed, and molded using a rubber press at a pressure of J ton/crl (D) for about 15 minutes.The raw material rod was then heated in an electric furnace at a pressure of 1700 °C-
Sintering was carried out for 20 hours. A ruby single crystal was grown using the sintered raw material rod using an FZ apparatus. The growing conditions are shown below.

Growth rate: 2. Omm/H Upper shaft rotation speed: 45 rpm Lower shaft rotation speed: 15 rpm Seed: Corundum single crystal Atmosphere: Air Growth time: 20 hours The crystal grown by the above method is a round rod with a length of 40cm and a diameter of aO. It was a high quality ruby single crystal with no bubbles throughout.

[Example 2] Reagent grade (999% or higher purity) α-alumina 409 was placed in a platinum crucible and treated in a vacuum sintering furnace at a temperature of 900°C and a vacuum of 10-' Torr for 2 hours. lol
A sintering raw material was prepared by adding t% of chromium oxide and 0.4W% of nickel oxide in the same manner as in [Example 1], and a Padparadscha single crystal was grown under the same growth conditions as in [Example 1]. I did it.

The crystal grown by the above method had a round bar shape with a length of 40 m+n and a diameter of aO, and was a high-quality Padparadscha single crystal without air bubbles throughout.

[Example 3] Using the same method as [Example 1], the temperature was 1200°C and the degree of vacuum was 10.
- Alumina 2512 treated for 2 hours at Torr and beryllia of special reagent grade (995% or higher purity) were treated at a temperature of 1200°C and a vacuum of 10 Torr as in the case of alumina.
5.67 r of IJ IJ treated for 2 hours was placed in a mortar, 0.14 r of chromium oxide and 1.09 r of iron oxide were added as coloring agents, and the following was carried out in the same manner as in [Example 1]. A sintered raw material rod was prepared, and alexandrite single crystal was grown under the same growth conditions as in [Example 1].

The crystal grown by the above method has a length of 40+++n and a diameter of aO.
It was a high quality alexandrite single crystal with a round bar shape and no bubbles throughout.

〔effect〕

As described above, according to the present invention, when growing a single crystal from a melt, alumina and beryllia, which are raw material powders for corundum crystals and alexandrite crystals, are grown at a temperature of 800°C.
~1500℃ and vacuum level 1O-1Torr-10-'
By processing at Torr, the growth rate is 5 rrr by the Fz method, regardless of the type of colorant.
Corundum crystals and alexandrite crystals grown at less than m/H have no bubbles and are useful for artificial jewelry, and have great effects in improving quality and productivity as electronic materials.

that's all

Claims (3)

[Claims] (1) In the method of growing a single crystal from a melt, the above-mentioned
A method for producing a raw material for single crystal growth, characterized by processing a raw material powder of a melt at high temperature and in a vacuum state. (2) - Claim 1, wherein the raw material powder is alumina (Attos) and BO2.
The method for producing raw materials for single crystal growth according to item 5. (3) The method for producing a raw material for single crystal growth according to claim 1, wherein the high temperature is 8003 to 1500°C and the degree of vacuum is 10-ITorr-10'''' IITorr (4)
The raw material manufacturing method is for single crystal growth using an infrared condensing floating zone method, and the crystal growth rate is 3. The method for producing a raw material for single crystal growth according to claim 1, characterized in that the growth is performed at a temperature lower than Ottrm/H.