JPH07126771A - Production of beryllium block having high purity and no blow hole - Google Patents

Abstract

PURPOSE:To provide a method for inexpensively producing beryllium block having high purity and no blow hole, from volatile impurity causing bumping is removed and the development of the blow hole is restrained. CONSTITUTION:Evacuation in a melting chamber 1 is executed to sufficiently remove the residual gas, and after filling inert gas, the evacuation in the melting chamber 1 is again executed to 10 Torr and high-frequency induction vacuum melting is executed at 1350 deg.C to the crude metallic beryllium reduced with magnesium in a crucible 6. At this time, in order to restrain the occurrence of bumping, the pressure in the melting chamber is controlled so as to hold 10-20 Torr to remove the volatile impurity, and the beryllium is melted within 1hr. The molten beryllium 5 is poured into a mold 2 made of a graphite from the crucible 6 and cooled gradually from the lower part by flowing the water through a pipe 4 to water-cooling a copper hearth 3, and the ingot having no blow hole can be produced. Since the beryllium block for vapor deposition can be produced only by one time vacuum melting, the shortened production process saves the production cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high purity non-porous beryllium block and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, in the purification of beryllium,
A vacuum is drawn to remove the residual gas in the melting chamber, then an inert gas is filled, the above-mentioned crude metal beryllium is started to be melted, and after the melting is completed, the process of casting in an uncooled mold is repeated twice. Therefore, a method of removing volatile impurities is known.

[0003]

However, in the conventional method for purifying beryllium, the refining of beryllium is expensive because the vacuum melting is repeated twice. Further, in this method, since the dissolution batch is large, the resulting beryllium ingot contains many pores with a diameter of about 20 mm. Therefore, when such a beryllium ingot is used as a material for vacuum deposition, bumping frequently occurs during vacuum deposition. There is a tendency.

Further, beryllium, which is purified by the method of performing vacuum melting once, has many volatile impurities, and bumping frequently occurs during vacuum vapor deposition, so that it is not suitable as a raw material for vapor deposition. Further, there is a problem that the pressure during melting cannot be lowered so much because the vapor pressure of beryllium is high. The present invention is
In order to provide a method for producing a high-purity non-porous beryllium block that suppresses the generation of pores and the removal of volatile impurities that cause bumping at low cost. To do.

[0005]

The method for producing a high-purity non-porous beryllium block of the present invention for achieving the above-mentioned object is to melt a crude metal beryllium under a depressurized inert gas atmosphere and melt it for a predetermined time. And a step of unidirectionally solidifying the melted product in a non-oxidizing atmosphere to form an ingot.

In this case, the non-oxidizing atmosphere in the step of unidirectionally solidifying into an ingot is preferably an inert gas atmosphere. The pressure level of the inert gas atmosphere is
100 Torr or less is suitable, preferably 50 Torr or less, and more preferably 30 Torr or less. This pressure level is selected as 100 Torr or less for an X-ray window member, for example, because the amount of impurities that absorb X-rays becomes a problem, and is 50 Torr or less for a high-purity ingot that requires better rolling properties. In addition, as the material for the vapor deposition vibration plate, 30 Torr or less is selected because it is necessary to remove volatile impurities.

The method for producing a high-purity non-porous beryllium block of the present invention includes, for example, a step of evacuating the melting chamber and then filling the melting chamber with an inert gas, and a vacuum of the melting chamber to a pressure of 10 In a melting chamber having a pressure of 10 to 20 Torr, in a melting chamber having a pressure of 10 to 20 Torr, for melting and refining crude metal beryllium in a melting state for a predetermined time. Unidirectionally solidifying to produce an ingot.

[0008]

According to the method for producing a high-purity non-porous beryllium block of the present invention, a high-purity non-porous beryllium block that suppresses the removal of volatile impurities causing bumping and the generation of pores can be produced at low cost. There is an effect that it can be manufactured.

[0009]

EXAMPLES Examples of the present invention will be described below. For example, as shown in FIG. 1, in the chamber 1, the composition of the crude metal beryllium is beryllium (Be): 98 wt% magnesium (Mg): 0.5 wt% fluorine (F): 0.25 wt%. It comprises a crucible 6 filled with a magnesium-reduced crude metal beryllium. And (1) In order to produce a high-purity beryllium ingot, the pressure inside the melting chamber 1 is set to 1 ×.
The residual gas is sufficiently removed by reducing the pressure to 10 ⁻⁵ Torr or less, for example, vacuuming. Vacuuming is performed by the vacuum pump 7. (2) Next, the interior of the melting chamber 1 is evacuated to 10 Torr after being filled with argon gas as an inert gas. (3) Then, high frequency vacuum melting is started for the crude metal beryllium in the crucible 6. At this time, as shown in the relationship between the melting time and the pressure in FIG. 2, in the conventional example, the pressure in the melting chamber 1 rises because volatile impurities such as magnesium and fluorine are vaporized along with the melting. (4) Therefore, as shown in FIG. 3, in the embodiment, the atmospheric pressure in the melting chamber 1 is set to 1
The volatile impurities are removed by adjusting the pressure to 0 Torr and maintaining it at 10 to 20 Torr. Since the loss of beryllium is large when the melting takes a long time, the high-frequency heating of this embodiment causes the beryllium to melt within a short time of less than one hour. The melting temperature is 1350 ° C. (5) Next, the molten metal is unidirectionally solidified.

FIG. 3 shows the relationship between the pressure and the dissolution yield of beryllium in the example. The above pressure 10-2
At 0 Torr, the yield is 80 to 85%. The yield of beryllium increases as the pressure increases, but the residual amounts of magnesium and fluorine also increase. In addition, in FIG.
The relationship between the content of magnesium and fluorine in the crude metal beryllium and the occurrence frequency of bumping with respect to the number of trials of vapor deposition is shown. It can be seen that the bumping frequency increases as the content of magnesium and fluorine increases. Therefore, from the relationship between the dissolution yield of beryllium and the residual amounts of magnesium and fluorine, the pressure range in which the occurrence frequency of bumping is most suppressed is 10 to 20 To.
The range of rr is desirable. The melting point of beryllium fluoride:
803 ° C., boiling point: 1159 ° C., melting point of magnesium fluoride: 1263 ° C., boiling point: 2260 ° C.

Next, as shown in FIG. 5, molten beryllium 5 is poured from a crucible 6 into a mold 2 made of graphite, and a copper hearth 3 is passed through a tube 4 to cool the water in a direction indicated by an arrow A. It was possible to manufacture ingots without pores by cooling from the bottom. In addition, as a comparative example, an experimental result by a method based on the conventional example, in which a vacuum melting of casting with a non-cooled mold is repeated twice after melting in a vacuum and the pressure in the chamber during vacuum melting is not adjusted. Are summarized in Table 1 together with the results of this example.

[0012]

[Table 1] According to the present embodiment, the raw material for beryllium vapor deposition is manufactured only once by vacuum melting, resulting in a short manufacturing process and cost reduction. Moreover, the pressure in the melting chamber 1 is always 10 to 2
By holding at 0 Torr, volatile impurities can be efficiently and sufficiently removed. Further, by unidirectionally solidifying with a water-cooled copper hearth, it is possible to manufacture an ingot without pores. Therefore, by removing the volatile impurities that are the cause of the bumping phenomenon that has been a problem during the vapor deposition of beryllium and suppressing the generation of pores, it is possible to achieve vapor deposition in which the occurrence frequency of the bumping phenomenon is extremely low.

In the manufacturing process of the high-purity beryllium vapor deposition ingot of the present embodiment, the heating and melting under the above-mentioned reduced pressure inert atmosphere is performed only once, and the pressure in the melting chamber is kept constant at 10 to 20 Torr. By controlling, impurities can be efficiently removed and a high-purity non-porous beryllium ingot can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an apparatus of a vacuum melting furnace according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between dissolution time and pressure in an example of the present invention.

FIG. 3 is a diagram showing the relationship between the pressure, the dissolution yield of beryllium, and the residual amounts of magnesium and fluorine after dissolution in the example of the present invention.

FIG. 4 is a diagram showing the relationship between the content of magnesium and fluorine and the occurrence frequency of bumping in the example of the present invention.

FIG. 5 is a view showing an apparatus for producing an ingot having no pores in the example of the present invention.

[Explanation of symbols]

 1 Melting Chamber 2 Graphite Template 3 Copper Hearth 4 Water Cooling Tube 5 Beryllium Melt 6 Crucible 7 Vacuum Pump 8 Beryllium Melt

Claims (2)

[Claims] 1. A step of heating and melting a crude metal beryllium in a reduced pressure inert gas atmosphere to hold it in a molten state for a predetermined time, and a step of unidirectionally solidifying the melted material into an ingot in a non-oxidizing atmosphere. A method for producing a high-purity non-porous beryllium block, which comprises: 2. The method for producing a high purity non-porous beryllium block according to claim 1, wherein the non-oxidizing atmosphere in the step of unidirectionally solidifying into an ingot is an inert gas atmosphere.