JPS62103308A - Ultrafine particle manufacturing equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for efficiently producing ultrafine particles.

[Conventional technology]

Conventionally, devices for producing ultrafine particles using an arc include Japanese Patent Publication No. 57-44725 or Japanese Patent Publication No. 58-fi416.
As described in No. 6, using a gas containing hydrogen, the hydrogen in this gas is dissolved and convected in the molten metal,
This mechanism for releasing hydrogen was used, but no consideration was given to production efficiency.

[Problem that the invention seeks to solve]

The present invention has been made in view of the above, and an object of the present invention is to provide an apparatus for efficiently producing ultrafine particles.

(Means for solving the problem) The above purpose is to arrange one or both of the electrodes facing each other as ultrafine particle raw materials, and to set a predetermined angle between the two electrodes so that the electromagnetic force caused by the arc current deflects the arc between the two electrodes. This is achieved by applying a carrier gas to the base material from behind the steam flame, and installing a collection chamber to collect ultrafine particles in the direction of the steam flame.

Furthermore, the above purpose is to place one or both of the electrodes facing each other as ultrafine particle raw materials, and to provide a predetermined angle between the two electrodes so that the electromagnetic force caused by the arc current deflects the arc between the two electrodes. A carrier gas is blown out from the rear and/or front of the steam flame, and the steam flame is transported to a collection chamber installed in the direction of the steam flame that collects ultrafine particles. This is achieved by providing a control device that controls the arc length to be constant by detecting the decrease or by controlling the arc length.

[Effect]

When one or both of the electrodes are placed facing each other as ultrafine particle raw materials and an arc is generated between the two electrodes, the ultrafine particle raw materials are heated, melted, and evaporated to produce ultrafine particles. The present invention utilizes the electromagnetic force generated by the arc current and provides a predetermined angle between the two poles to deflect the arc between the two poles, thereby reducing the electromagnetic force that changes depending on the magnitude of the current to the generation of ultrafine particles. This device is used for conveyance, and the production efficiency of ultrafine particles is greatly improved. By suctioning the flow, ultrafine particles are transported to the collection chamber in front of it. This improves the production efficiency of Al fine particles, and the ultrafine particles are cooled by the carrier gas, making it possible to obtain high quality ultrafine particles.

〔Example〕

The present invention will be explained in detail below. FIG. 1 shows an example of an ultrafine particle manufacturing apparatus using the present invention.

1 is a chamber of an ultrafine particle manufacturing apparatus, 2 is a water-cooled crucible, and 3 is a material for manufacturing ultrafine particles (hereinafter referred to as base material), which is used as an anode through the water-cooled crucible in this embodiment. The other electrode 4 is made of a base material or an electrode material such as tungsten, and is used as a cathode in this embodiment.

Reference numeral 5 denotes an arc (steam flame) generated between the two electrodes, which contains ultrafine particles generated from the base material.

6 is a nozzle that blows out the carrier gas; 7 is the carrier gas; 68 is a collection chamber for ultrafine particles; 9 is cooling water for the crucible; 10 is a drive unit that raises or lowers the crucible;
Reference numeral 11 indicates a shaft connected to the drive unit, 12 a power source for applying voltage between the base material 3 and the electrode 4, and 13 a gas cylinder.

When producing ultrafine particles, first, the inside of the chamber 1 is evacuated using a vacuum pump (not shown). This is to prevent the produced ultrafine particles from being oxidized or to keep the composition of the oxide ultrafine particles constant. After evacuation, the chamber J is filled with atmospheric gas (inert gas such as argon, helium, nitrogen, etc., hydrogen-containing or carbon-based gas such as hydrogen, methane, propane, or a mixture of these gases and inert gas). or, in order to produce ultrafine oxide particles, a predetermined current and voltage are applied between the zero-order base material 3 in which a gas containing oxygen groups is sealed up to a predetermined pressure and the electrode 4,
Generate arc 5. The length and shape of the arc 5 are determined by the angle between the base metal 3 and the electric current, and the voltage.
The illustrated length and shape can be achieved by the electromagnetic force generated by the arc current flowing between the two poles. arc 5
The steam flame contained in the gas is transported by a carrier gas 7 (usually atmospheric gas is used) that is blown out from a carrier gas nozzle 6.
It is rapidly cooled to become a mixed fluid of ultrafine particles and carrier gas, and the ultrafine particles are collected by a collection chamber 8 installed in the direction of the flame tail of the arc 5 . The length and shape of the arc 5 change depending on the distance between the surface of the base material 3 and the tip of the electrode 4, so if the base material; 3 decreases due to the generation of ultrafine particles and the arc length increases, the crucible is The section 1o is operated to raise the crucible via the shaft 11, and the length and shape of the arc 5 are maintained well.

Figure 2 shows how the angle O between the base material 3 and the electrode 4 (hereinafter referred to as electrode angle) is changed from 15 degrees to 90 degrees using the apparatus shown in Figure 1.
The graph shows the change in the production amount ratio when changing the amount up to a certain degree. In this example, the base material 3 is nickel, the electrode 4 is made of 2% tritriium oxide, has an outer diameter of 4 nya, the atmosphere is a mixed gas of argon + 50% hydrogen, and the atmospheric pressure is about 0.1 MP.
a. The conditions are: arc current 150A, arc voltage 35V. Assuming that the amount of production when the electrode angle is 90 degrees, that is, when installed vertically, is 1, the production amount ratio shows a peak value of 2.8 at a position where the electrode angle is 40 degrees. The reason why the peak value is shown at an electrode angle of 40 degrees is that the arc 5 is narrowed by a thermal pinch due to the action of hydrogen contained in the atmospheric gas, and the power source 12
sufficient power is input to the base material 3 from 150A
It is thought that this is because the aperture 5 is deflected due to the electromagnetic force generated by the current, and the generated ultrafine particles are blown away in the direction of the flame tail. To further assist this, the carrier gas 7 is blown out from the carrier gas nozzle 6 shown in FIG.
Ultrafine particles can be produced efficiently by aiding transportation and rapid cooling. This carrier gas nozzle 6 is positioned as shown in FIG. 3, and by sucking the flame tail of the deflected arc 5,
Ultrafine particles can be transported and rapidly cooled to a collection chamber 8 degrees in front of it.

11') A suitable range of the electrode angle O between the material 3 and the electrode 4 is between 5 degrees and 50 degrees, as is clear from FIG. Although this value mainly changes depending on the value of the arc current, the above range is preferable at least in the range of arc current from 70A to 50OA. If the electrode angle is less than 15 degrees, it will be very difficult to start the arc, and it will be difficult to maintain the arc due to minute changes in the melting surface when the arc is generated.
It also becomes unstable, and arc breakage is more likely to occur. Furthermore, if the temperature exceeds 50 degrees, the efficiency of producing ultrafine particles will decrease significantly.

In the example shown in FIG. 2, the base material was nickel, but similar efficiency was observed with other materials. Examples are shown in the table.

In the table, the electrode is made of tungsten containing 2% thorium and has an outer diameter of 4 m.
m, ff The surrounding atmosphere is a mixed gas of argon + 50% hydrogen, the atmospheric pressure is about 0.1 MPa, the arc current is 200 A, and the arc voltage is 35 to 40 V.

As in the case of FIG. 2, when the production amount at an electrode angle of 90 degrees is set as 1, the production amount ratio at an electrode angle of 45 is shown.

Further, in this embodiment, the carrier gas nozzle 6 is placed at the position shown in FIG. 3, a carrier gas having the same composition as the atmospheric gas is used, and the carrier gas flow rate is 100 fl/win. As is clear from the table, the effects of the present invention were observed with various materials.

It is common to use a material with a high melting temperature, such as W or Ta, for the electrode 4 to generate ultrafine particles, but if the same material is used for the base material 3 and the electrodes 4, even higher purity can be obtained. High quality ultrafine particles can be obtained. Further, ultrafine particles in which two or more metals are mixed or alloyed can be obtained by using a base material or an electrode of an alloy raw material, or by changing the materials of both electrodes. 3 jC+ T, carbide such as ]-C, T
iN.

In order to generate ultrafine particles of compounds such as nitrides such as SigN+ and oxides such as AQzOs and SnO2,
Gases containing carbon groups, nitrogen groups, and oxygen groups may be mixed in the atmosphere.

The amount of ultrafine particles produced varies depending on the polarity, but they can also be produced using direct current or alternating current with the opposite polarity to that of this embodiment.

The position of the outlet for the carrier gas to be blown out from behind or in front of the steam flame is preferably in the direction of the collection chamber 8. Also, the type of carrier gas is usually the same as the atmospheric gas, but
It is also possible to change the type of gas. '8 Although the ambient pressure is usually approximately atmospheric pressure, it is also possible to produce ultrafine particles at low or high pressure.

To increase the amount of production, place multiple base materials and/or electrodes, set one of the electrodes to a common potential, place multiple carrier gas outlets, and place a collection chamber (this is one If the electrodes are installed in multiple locations, the amount of production can be increased in proportion to the number of electrodes.

The size of the ultrafine particles generated is large when generated using the conventional hydrogen arc method as the steam flame is reheated by the arc, but according to the method of the present invention, the electromagnetic force generated by the arc current is By deflecting the arc, the steam flame can be quickly moved away from the high-temperature part of the arc, and because the carrier gas is blown out from the front or rear to rapidly cool the steam flame, the particle size is smaller compared to the conventional hydrogen arc method, and The variation in diameter is also reduced.

FIG. 4 shows yet another embodiment in which a control device 14 is added. Specifically, the control table @14 is a device that detects arc voltage and controls the arc length so that this voltage becomes a predetermined value, and outputs a signal to the drive unit 10 to raise or lower the crucible 2. (The control device 14 is a control device that keeps the arc length constant by detecting the weight of the base material 3, or a control device that inputs conditions to predict the weight loss of the base material 3 and keeps the arc length constant. ).

With the above configuration, since the length and shape of the arc 5 change depending on the distance between the surface of the base material 3 and the tip of the electrode 4, the arc voltage is detected by the control device 14, and the reference voltage set in the control device 14 is Compare and set the crucible drive unit 10 to 'fJ!' to match the reference voltage. 6 and move the shaft 11 up and down to maintain a constant voltage.

This makes it possible to maintain a good length and shape of the arc 5.

〔Effect of the invention〕

According to the present invention, one or both of the electrodes are arranged to face each other as raw materials for ultrafine particles, and an appropriate angle is provided between the two electrodes so that the electromagnetic force caused by the arc current deflects the arc between the two electrodes. By blowing out carrier gas from behind or in front of the flame and providing a collection chamber that collects ultrafine particles in the direction of the steam flame, ultrafine particles can be collected with 2 to 20 times higher efficiency than conventional hydrogen arc heating methods. It is effective in manufacturing.

[Brief explanation of drawings]

Figures 1 to 4 are explanatory diagrams of the ultrafine particle manufacturing apparatus according to the present invention, where Figure 1 is a schematic diagram of the ultrafine particle manufacturing apparatus, and Figure 2 shows the influence of the electrode angle on the amount of ultrafine particles produced. FIG. 3 is a partial diagram of another embodiment of the apparatus, and FIG. 4 is a schematic diagram of still another embodiment of the apparatus. 1... Chamber, 2... Crucible, 3... Base material, 4
... Electrode, 5... Arc, 6... Carrier gas outlet, 7... Carrier gas, 8... Collection chamber, 10...
Drive unit, 12...power supply 14...control device.

Claims (1)

[Claims] 1. In an apparatus for producing ultrafine particles by generating an arc between a base material to be evaporated and an electrode, one or both of the electrodes are arranged facing each other as ultrafine particle raw materials, and the electromagnetic force due to the arc current is polarized. A predetermined angle is provided between the two poles so as to deflect the arc between them, and an outlet is provided behind the steam flame of the base metal to blow carrier gas, creating a collection chamber that collects ultrafine particles in the direction of the steam flame. An apparatus for producing ultrafine particles characterized by the following: 2. In claim 1, a carrier gas outlet is provided in the direction of the steam flame of the base material, and by sucking the flow of the steam flame, ultrafine particles are delivered to the collection chamber in front of the outlet. An apparatus for producing ultrafine particles characterized by conveyance. 3. In claim 1, the angle provided between the two poles is set between 15 degrees and 50 degrees so that the electromagnetic force caused by the arc current deflects the arc between the two poles. Ultrafine particle manufacturing equipment. 4. In a device that produces ultrafine particles by generating an arc between the base material to be evaporated and the electrodes, one or both of the electrodes are placed facing each other as ultrafine particle raw materials, and the electromagnetic force generated by the arc current deflects the arc between the two electrodes. A predetermined angle is given between the two poles so that the back of the steam flame of the base material and/or
Alternatively, ultrafine particles characterized by being provided with a means for blowing out a carrier gas from the front and conveying the steam flame to a collection chamber installed in the direction of the steam flame to collect the ultrafine particles to keep the arc length constant. manufacturing equipment. 5. The ultrafine particle manufacturing apparatus according to claim 4, wherein the means for making the arc length constant is a control device that detects the arc voltage and makes the arc voltage constant. 6. The apparatus for producing ultrafine particles according to claim 4, characterized in that the means is a control device that detects a decrease in the weight of the base material and keeps the arc length constant. 7. In claim 4, the means for keeping the arc length constant is a control device that makes the arc length constant by predicting the relationship between the ultrafine particle generation conditions and the weight loss of the base material. An apparatus for producing ultrafine particles characterized by the following. 8. Claim 4 is characterized in that the angle provided between the two poles is set between 15 degrees and 50 degrees so that the electromagnetic force caused by the arc current deflects the arc between the two poles. Ultrafine particle manufacturing equipment.