JPH09110588A - Production of single crystal copper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a single crystal copper from a melt of highly purified copper by a simple method without requiring the use of an apparatus having any special structure or the performance of any complex treating operation. SOLUTION: A highly purified copper 2 having >=4N purity is melted in a crucible 1 made of a Vitrocarbon (R) and held at >=1,150 deg.C for >=10min to decompose and reduce copper oxides causing polycrystallization, then a single crystal is obtained. A drawn single crystal copper plate is obtained through a slit 4 provided at a bottom part of the crucible and having 1mm thickness and 10mm breadth by using a pulling down shaft 5 at a drafting speed of 60mm/h.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a single crystal of metal, and more specifically, it aims to produce single crystal copper by a simple means by heating and holding under a specific condition for a predetermined time. To do.

[0002]

2. Description of the Related Art Conventionally, when a single crystal of a metal such as copper is produced, an oxide is usually generated on the surface of a raw material by air or the like. It was necessary to carry out reduction treatment with H ₂ , CO gas and the like.

Further, in the method of producing a single crystal by melting using a vertical crucible or the like, it is necessary to remove the karami floating in the upper part when the raw material is melted. In this case, there is a risk that the karami will adhere to the container. Therefore, in order to transfer only the melt containing no kalami to another container for crystal growth, it takes time and labor for the melting process, and the growth furnace itself has a complicated shape.

[0004]

As described above, in the conventional method for producing a metal single crystal body, since a special apparatus is often used, there is a problem that the production cost becomes high accordingly. It was Therefore, an object of the present invention is to develop a new production method capable of producing a single crystal body by using an apparatus having a simple structure instead of the conventional method.

[0005]

[Means for Solving the Problems] The inventors of the present invention have conducted diligent research to solve such problems. As a result, the target single crystal copper is melted by melting under a specific condition using a crucible made of a special material. It has been found that it can be produced and the method of the present invention can be provided.

That is, the present invention is characterized in that high-purity copper as a raw material is melted in a crucible and then held at a temperature of 1150 ° C. or higher for at least 10 minutes to decompose the copper oxide to form a single crystal. The method for producing single crystal copper is characterized in that the crucible is made of a special carbon material such as graphite or vitro carbon (trade name of vitreous carbon material manufactured by Nippon Carbon Co., Ltd.). .

[0007]

As a material of the crucible (2 inch inner diameter) in the melting furnace used in the method of the present invention, graphite or a special carbon material such as vitro carbon material can be used.
By using these crucibles, carbon on the surface of the crucible can reduce and remove oxides of copper in the material. Since the presence of copper oxide causes polycrystallization, decomposition and reduction of copper oxide can facilitate single crystallization. It has been found that the use of a special carbon material such as graphite or vitro carbon allows the copper oxide to be conveniently decomposed during the above high temperature holding.

One of the means for manufacturing using the special graphite crucible is a plate-shaped single crystal body of interest which is provided with a small hole for drawing out the melt from the bottom of the crucible and water cooling in the pulling down shaft. Is a drawing method for producing.

Another means is to install the above-mentioned special graphite crucible in a Bridgman furnace and melt it.
This is the Fridgeman furnace method for producing a straight-tube type single crystal while lowering the temperature.

Hereinafter, the present invention will be described in detail based on examples, but the scope of the present invention is not limited to these.

[0011]

Example 1 Using the copper drawing test furnace manufactured by Dowa Mining Co., Ltd. shown in FIG. 1, 6N (99.9999%) high-purity copper 2 was first charged into a 2 inch inner diameter crucible 1 made of a vitro carbon material, The heater 3 was heated to 1150 ° C. to melt the high-purity copper and held for 5 hours.

After that, a slit 4 having a thickness of 1 mm and a width of 10 mm provided at the bottom of the crucible is used to pull down 6 by using a pulling shaft 5.
When pulled out at a speed of 0 mm / h, 1 mm x 10 mm width x 1
A single crystal copper plate of 00 mmL could be obtained. 6 in FIG.
Is a heat insulating material, 7 is a graphite material, 8 is an upper heater, 11
Is the drive shaft.

[0013]

Example 2 Using a vertical Bridgman furnace manufactured by Dowa Mining Co., Ltd. shown in FIG. 2, 1 kg amount of 6N high-purity copper 2 was first charged into a 2 inch inner diameter Vitrocarbon crucible 1 and melted by a central heater 3. After holding at 1250 ° C for 1 hour, the upper part of the raw material was adjusted to 1130 ° C and the lower part of the raw material was adjusted to 1083 ° C (melting point), and the inside was solidified while lowering the crucible at a speed of 30 mm / min. A 50 mm copper single crystal ingot could be obtained. In FIG. 2, 9 is a lower heater, 10 is a water cooling shaft, and 12 is a temperature sensor.

[0014]

[Comparative Example 1] Example 1 was carried out using the drawing apparatus shown in FIG.
In the same manner as shown in 6), 6N high-purity copper was melted by heating and then immediately pulled out from the bottom of the crucible without holding it at a constant temperature to obtain a copper plate with a size of 1 mm × 10 mm width × 100 mmL. It remained as a polycrystalline body.

[0015]

Comparative Example 2 Using the vertical Bridgman furnace shown in FIG. 2, 6N high-purity copper was melted up to 1250 ° C. in the same manner as in Example 2, and then immediately heated to 30 mm / h without holding at a constant temperature.
When the solidification was performed while lowering the crucible at the pulling speed of, a copper ingot having a straight tube length of 50 mm was obtained, and the ingot was a polycrystalline body.

[0016]

As described above, in the method of the present invention, a special carbon material crucible such as a graphite crucible or a vitro carbon material crucible is used to carry out a melting treatment under a specific condition to obtain a raw material required in the conventional method. Since the operation of the surface treatment step and the step of separating the kalami are unnecessary, there is an advantage that a single crystal of copper can be manufactured by a simple manufacturing method.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the structure of a drawing device used in Example 1 of the present invention.

FIG. 2 is a schematic diagram showing the structure of a Bridgman furnace used in Example 2 of the present invention.

[Explanation of symbols]

 1 Graphite crucible 2 High-purity copper 3 Central heater 4 Slit 5 Pull down shaft 6 Insulation material 7 Graphite material 8 Upper heater 9 Lower heater 10 Water cooling shaft 11 Drive shaft 12 Temperature sensor

Claims (3)

[Claims] 1. A high-purity copper of 4N or more as a raw material is melted in a crucible and then held at a temperature of 1150 ° C. or more for at least 10 minutes to decompose the copper oxide to form a single crystal. And a method for producing single crystal copper. 2. The method for producing single crystal copper according to claim 1, wherein the crucible is made of graphite or a special carbon material. 3. The method for producing single crystal copper according to claim 2, wherein the special carbon material is vitro carbon.