JP3719452B2 - Method for producing single crystal copper - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for producing a single crystal of metal, and more specifically, an object of the present invention is to produce single crystal copper by a simple means by heating and holding for a predetermined time under specific conditions.
[0002]
[Prior art]
Conventionally, when producing a single crystal of a metal such as copper, for example, an oxide is usually generated on the surface of the raw material by air or the like. Therefore, etching of the surface or H ₂ , CO gas before the single crystal is produced. It was necessary to perform a reduction treatment with the above.
[0003]
Furthermore, in the method of producing a single crystal by melting treatment using a vertical crucible or the like, it is necessary to remove the calami floating above when the raw material is melted. In this case, there is a risk that the calami adheres to the container. Usually, only the melt containing no calami is transferred to a separate container for crystal growth, so that it takes time for the melting process and the growth furnace itself has a complicated shape.
[0004]
[Problems to be solved by the invention]
As described above, in the conventional method for producing a metal single crystal, a special apparatus is often used, which has a problem in that the production cost increases. Accordingly, an object of the present invention is to develop a novel manufacturing method capable of manufacturing a single crystal using an apparatus having a simple structure instead of the conventional method.
[0005]
[Means for Solving the Problems]
The present inventors have intensively studied to solve such a problem, and found that the target single crystal copper can be produced by melting under a specific condition using a special material crucible and provides the method of the present invention. We were able to.
[0006]
That is, the present invention melts 6N high-purity copper as a raw material in a crucible made of graphite or a glassy carbon material and provided with a slit at the bottom, and then holds it at a temperature of 1150 ° C. or higher for at least 10 minutes or more. A method for producing single crystal copper, comprising obtaining a single crystal copper plate by decomposing copper oxide, drawing the melt from the slit using a shaft, and cooling with water.
[0007]
[Action]
As a material for the crucible (2 inch inner diameter) in the melting furnace used in the method of the present invention, a special carbon material such as graphite or a vitrocarbon material can be used. By using these crucibles, carbon in the surface of the crucible is contained in the material. Copper oxide can be removed by reduction. Since the presence of copper oxide causes polycrystallization, single crystallization can be facilitated by decomposing and reducing it. It has been found that the use of a special carbon material such as graphite or vitrocarbon can advantageously decompose the copper oxide during the high temperature holding.
[0008]
One of the means for producing using the above-mentioned special graphite crucible is to produce a target plate-shaped single crystal by providing a small hole for extracting the melt at the bottom of the crucible and cooling with water in the pulling shaft. It is a drawing method.
[0009]
Another means is the Friedman method for manufacturing a straight cylindrical type single crystal while lowering the temperature of the above-mentioned special graphite crucible placed in a Bridgeman furnace and melted.
[0010]
EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, the scope of the present invention is not limited to these.
[0011]
[Example 1]
First, 6N (99.9999%) high-purity copper 2 was first charged into a crucible 1 having a 2-inch inner diameter made of a vitro carbon material, and 1150 ° C. at a central heater 3 using the Dowa Mining copper pull-out test furnace shown in FIG. Until high purity copper was melted and held for 5 hours.
[0012]
Then, when it pulled out at a speed | rate of 60 mm / h using the pulling-down shaft 5 from the slit 4 of thickness 1mm x width 10mm provided in the crucible bottom part, the single crystal copper plate of 1mm x 10mm width x 100mmL was able to be obtained. In FIG. 1, 6 is a heat insulating material, 7 is a graphite material 8 is an upper heater, and 11 is a drive shaft.
[0013]
[Reference Example 1]
First, 1 kg of 6N high-purity copper 2 was charged into a vitrocarbon crucible 1 having a 2-inch inner diameter, melted by a central heater 3, and heated at 1250 ° C. After maintaining the time, 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 crystalline ingot could be obtained. In FIG. 2, 9 represents a lower heater, 10 represents a water cooling shaft, and 12 represents a temperature sensor.
[0014]
[Comparative Example 1]
Using the drawing device shown in FIG. 1, 6N high-purity copper was heated and melted as shown in Example 1, and then immediately pulled out from the crucible bottom without being held at a constant temperature. Copper plates were obtained, but these remained polycrystalline rather than single crystalline.
[0015]
[Comparative Example 2]
Using the vertical Bridgman furnace shown in FIG. 2, after melting 6N high-purity copper to 1250 ° C. as shown in Reference Example 1 , immediately lowering the crucible at a pull-down rate of 30 mm / h without holding it for a certain period of time. When solidified, a copper ingot having a straight cylinder length of 50 mm was obtained, but the ingot was a polycrystal.
[0016]
【The invention's effect】
As described above, in the method of the present invention, by using a special carbon material crucible such as a graphite crucible or a vitro carbon material crucible, by performing a melting treatment under specific conditions, the surface treatment step of the raw material required in the conventional method or Since the operation of the separation process of calami is 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.
2 is a schematic view showing the structure of a Bridgman furnace used in Reference Example 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Graphite crucible 2 High purity copper 3 Central heater 4 Slit 5 Pull-down shaft 6 Heat insulating material 7 Graphite material 8 Upper heater 9 Lower heater 10 Water-cooled shaft 11 Drive shaft 12 Temperature sensor

Claims (1)

6N high-purity copper as a raw material is melted in a crucible made of graphite or glassy carbon and provided with a slit at the bottom, and then kept at a temperature of 1150 ° C. or higher for at least 10 minutes to decompose copper oxide A method for producing single crystal copper, comprising: obtaining a single crystal copper plate by drawing out the melt from the slit using a pulling shaft and cooling with water.

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