JPS60149705A - Method and device for forming ultrafine alloy particles by evaporation in gas method - Google Patents

Abstract

PURPOSE:To form substantially all the assemblages of the cooled and captured ultrafine particles to fine alloy particles by preparing a metallic material having the lower vapor pressure as a molten metal in an evaporating state into a vessel and supplying continuously the other metallic material thereto. CONSTITUTION:A metallic ingot 2 having the lower pressure is prepd. in a crucible 2 provided in a treating vessel 1. An induction heating coil 5a is activated to heat and melt the metallic ingot (a) in the crucible 2 until said ingot evaporates. The other metal (b) having the higher vapor pressure is continuously supplied in the form of a bar, pellet, etc. through a metallic material supply port 10 into the molten metal (a). The outside circumference of the metal (b) is enclosed with the metal (a) and is supplied in the form of a composite metallic material 16 in this case. When the tip end of the material 16 is dipped in the molten metal, the enveloping metal (a) melts and the metal (b) of the core melts and evaporates. The vapors of both metals (a), (b) collide and fuse against and to each other thus forming ultrafine alloy particles. The formed fine particles are cooled by a convectional inert gas during the ascending thereof and are grown to prescribed particles which are then stuck to the cooled sticking plate 6 in a capturing pipe 4. The particles are recovered in a receiving tray 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, as a method for producing ultrafine alloy particles by in-gas evaporation method, the vapor pressure is large (for example, Ii'e, Co, Ni
, Or, Ou, etc., and a metal selected from metals with higher vapor pressure such as Zn, Cd, Mg, etc.) At the evaporation temperature, the vapor pressure is Since there is a difference of 6 to 8 orders of magnitude, for example, attempts have been made to charge Ou, which has a relatively low vapor pressure, and Zn, which has a relatively high vapor pressure, into the same evaporation source and evaporate it, but first, the vapor pressure Because of the phenomenon that O, which has a low vapor pressure, begins to evaporate at the point where molten Zn with a high vapor pressure has completely evaporated, most of the ultrafine particles that are generated are individual ultrafine particles of O and Zn, respectively. However, the aggregate is obtained only as a mixture of individual ultrafine particles.

As another production method, for example, two evaporation gaps are provided in the processing container corresponding to two types of metal particles, and the heating temperature of each evaporation source is changed by 1 to increase the vapor pressure of the two types of metals. Attempts have been made to evaporate each of them in parallel while controlling each of them, with the hope that the ultrafine particles of the generated vapor will collide and fuse as they grow in the gas, but it has not been possible to achieve sufficient fusion and fusion. This did not occur, and the generation of ultrafine alloy particles was extremely small, and most of the collected aggregates were ultrafine particles of the metal of husbando alone.

The present invention improves the drawbacks of the conventional method, makes it easier to generate the sound of evaporated ultrafine particles of alloy by evaporation in gas, and the aggregate of the cooled and collected ultrafine particles is made up of all alloy ultrafine particles. In this method, two or more alloy ultrafine particles having different vapor pressures are generated by whole gas evaporation method. Among the seeds or five or more metal materials, a metal phase with the lowest vapor pressure is prepared in the evaporated molten metal, and the remaining one or more metal materials are continuously supplied. This is a full feature.

Next, an embodiment of the production method of the present invention and an example of its apparatus will be described with reference to the attached drawings.

FIG. 1 shows an example of a generation apparatus for carrying out the production method of the present invention. The upper surface of the ultrafine particle collection tube (4) is connected to the inlet (3) where the
) is connected to a vacuum exhaust system (not shown).

The evaporation source (2) consists of a crucible and is equipped with heating means (5) around its outer periphery. The heating means (5) consists of, for example, an induction heating coil (5aJ) and an external 65-frequency power source (5b) connected to it. A collection chamber (8) is connected to the side through an on-off valve (7). (12+ is a collection tray,
(131 indicates the operating rod. According to the present invention, a cylindrical seal member (9) is provided on the outer periphery of the upper side wall of the processing container (1).
A metal material supply port (101 is provided. Uυ
Figure 1 shows the inert gas outlet.

Examples of the method for producing ultrafine alloy particles of the present invention using the above-described apparatus of the present invention will be described below. To explain the method for producing ultrafine alloy particles of two metals with significantly different vapor pressures, the metal with the lower vapor pressure is prepared in the crucible (2), and the processing vessel (2) is kept in an airtight state. 1) One-way inert gas (Ar, He,
, Xθ, etc.) is introduced as indicated by the arrow, and the inside of the container is maintained at a predetermined inert gas pressure under the convection of the gas. In this state, one high frequency tπ source (dielectric heating coil connected to 5bJ)
51L) ffi is activated, and the gold H in the crucible (2j) is heated and melted to form a molten metal and evaporated. fibi, inserted airtightly from the metal material supply port 00) and continuously supplied to the molten gold Ma.
As one supply form, the metal b't is made into a longitudinal rod-shaped body in advance, and the outer periphery of the rod-shaped body is covered with a cylindrical formed body of the metal a having a low vapor pressure, and a coaxial rod-shaped composite metal material (161
This is airtightly inserted through the supply port (101), its tip is immersed in the crucible (2), and fed continuously at the required speed.
The metal a (C) on its outer periphery is protected from being melted or evaporated by the radiant heat from the evaporation source during its supply and the heat of steam a evaporating from the molten metal, and its tip is immersed in the molten metal. Due to the expansion, the enveloping metal a melts and the core metal vapor melts and evaporates, and the metal vapor is
By ensuring that the metal vapor rises within the chamber, sufficient opportunity is given for collision and fusion of both metal vapors a and b to produce ultrafine particles of the alloy.

The ultrafine alloy particles produced in this way are cooled during their ascent by a single convection inert gas, and as they grow, they are
- Particles in the range of several μm enter the collection tube (4) and adhere to the cooling adhesion plate (6). Scrape and collect in the collection tray Q2+. The collected ultrafine particles can be stored in the collection chamber (8) as is or with a full introduction valve (14) such as "2r02".
After the surface is slowly oxidized, it is taken out from the recovery chamber +8J. Alternatively, N2 gas can be introduced at atmospheric pressure 1 and sealed into the bottle using a glove. Then, the entire group of collected ultrafine particles was inspected, and each particle was found to be an alloy ultrafine particle consisting of metals a and b, metal a,
Ultrafine particles consisting of b alone were completely destroyed. The alloy composition ratio of each ultrafine alloy particle was determined as f' since a homogeneous aggregate with almost no variation was obtained.

As a result of various experimental studies, the weight of metal a filled in the crucible is 1
(b) The amount of ultrafine particles to be generated is approximately 100 times that of the predetermined amount of ultrafine particles, and the alloy in the ultrafine particles collected when the composite metal material F-1 is completely fed at a constant rate and evaporated from the beginning to the end of the filled metal. It was found that the variation in composition was only about 0.1% and did not change significantly, and that ultrafine alloy particles with no large change in magnetic properties were obtained. Incidentally, the pressure of the inert gas is generally controlled between 1 Torr and 100 Torr by adjusting the supply amount of the inert gas and the exhaust gas L.

Next, a detailed manufacturing example of d' will be explained in which all of the above-mentioned apparatuses are used.

Approximately 5 images of oumiu were placed in the pot to be polished, and after exhausting the processing volume to 1 x 10 m, the pressure inside the container was raised to H.
e Adjust the Hθ gas supply amount and displacement so that it is 3.0 torr. A high-frequency 1f current is passed through the induction heating coil to fully heat and melt the Cu mass in the crucible, and the temperature is raised! Let's go. Power output 601 (w The temperature of the molten metal reached 15% in about 1 hour after turning on the power.
50' (:), Gu was evaporated. Almost at the same time as this Ouu emission started, a Zn rod with a diameter of 6.2 heads was encapsulated with an O cylinder with an outer diameter of 10 mg and an inner diameter of 4H and a wall thickness of 5 balls. The coaxial rod-shaped composite metal paste was supplied through the entire vacuum seal supply port to the high-temperature O molten metal.Thus, at the tip of the rod, the O on the outer periphery and the Zn inside were simultaneously and continuously melted and evaporated. In this way, all of the ultrafine particles introduced into the upper collection tube were collected, and after surface slow oxidation treatment, they were released into the atmosphere and their aggregates were analyzed. 0u-
It was confirmed that the material was composed of Zn alloy ultrafine particles.
A) It was. That is, the composition analysis of 0u-Zn is
This was carried out using a fluorescent X-ray analyzer, but only one ultrafine particle was detected.
For component analysis of Ou-Zn in the specimen, an electron energy loss spectrum analysis method attached to a transmission electron microscope was used. The particle size was measured using an electron micrograph. Furthermore, in analysis using electron energy loss spectrophotography, it was confirmed that the spectra from individual particles and the spectra from a group of particles were in good agreement, and it was found that there was no significant segregation between particles.

In the above implementation, the supply rate of the coaxial composite rod of 0u-Zn (Yu/Kan) 1, which is stated separately, and the Zn heavy rod supply rate (
7xm and the Zn component ratio in the produced ultrafine alloy particles was investigated, and all the relationship curves shown at A in FIG. 2 were obtained. In addition, the total output of the high frequency power supply is 7Mi, and the molten metal temperature of L and Ou is 15
The relationship curve shown in \B was obtained by carrying out exactly the same procedure as above except for 00" (:).
.

The main one was VC300A. As is clear from the above, it can be seen that the ratio U of the alloy components of the ultrafine alloy particles, the feeding rate of the Zn rod, and the evaporation temperature of the molten metal vary greatly.

Next, an example of producing ultrafine particles of a quinary alloy as a three-phase (all-metal material) will be described.

Production Example 2 In the same manner as Production Example 1, the N1 lump with the lowest vapor pressure was charged into a three-edge crucible, and the pressure inside the container (i2.0) and the molten metal temperature were adjusted to 1800"CK to evaporate Ni. .

At the same time as Ni evaporation, a Pb rod with a diameter of 3.2H was added to a thickness of □, 5M.
Tape it in the same way as Ag f taping with a width of 10 m, and further tape the outer periphery of the tray with an outer diameter of 8 tj and an inner diameter of 5 tm and a wall thickness of 1.
A coaxial rod-shaped composite metal material encapsulated in a cylindrical body of N1 for 5 minutes was fed into the N1 molten metal through a fully vacuum-sealed supply port. Thus, at the tip of the rod, Ni on the outer periphery and Ag and Pb on the inside simultaneously and continuously melt and evaporate. The ultrafine particles thus led to the upper collection tube were collected, and after surface slow oxidation treatment, they were taken out into the atmosphere and analyzed for their aggregates, which revealed that all of them were Ni-Pb-Ag alloys with approximately uniform composition. It was confirmed that it was composed of ultrafine particles.

The particle size is 200~60OA, mainly 40OA and β
It was. For the compositional analysis of Ni-Pb-Ag, a fluorescent X-ray spectrometer and an electron energy loss spectrum analysis method attached to a transmission electron microscope were used in the same manner as described above. As a result, Ni-
It was found that the segregation between the Pb-Ag super@ particles was not large.

In the above example, the relationship between the feed rate (mm/min) of the Ni-Pb-Ag coaxial composite rod and the component ratio in the produced ultrafine alloy particles was investigated, and the results shown in Figure 3 were obtained. In the above example, it was shown that the metal material on the side with higher vapor pressure is coated with the same material as the metal material of the molten metal in order to prevent melting and evaporation due to heat in the container during supply. Alternatively, for example, insulating or heat-resistant pipes can be used. In this case, even if the supplied metal material is in the form of pellets, powder, etc., it can be continuously supplied to the molten metal through the pipe. To completely heat and melt the metal material for the molten metal evaporation source, direct resistance heating, indirect resistance heating arc method, and any other heating means can be selected and used.

As a result of many experimental studies, it has been found that when the difference between the vapor pressure of the metal material for the molten metal evaporation source and the vapor pressure of the metal material for supply is at least four orders of magnitude large, the method of the present invention can be applied to the conventional method. It was found that the effect was significantly greater than that of the previous one. Regarding the relationship between the two types of metals, as a system of 1,000 with a small vapor pressure, the above Ou vs. Zn
In addition, for example, metals such as Au, Ag, Pt, etc.
Magnetic materials such as Fe, Co, Or, A! Conductive materials such as Od, Pb+ as systems with higher vapor pressure
Metals such as Mn, Mg, Na or Sm, O
It is used selectively from rare earth metals such as e and La. As long as this relationship is satisfied, the difference in vapor pressure between two or more types of metals on the supply side may be 4 digits or less, or 2 digits or less (of course), but preferably 3 digits or more.

1. Although not shown in the drawings, the metal material can be supplied by using a pellet-shaped metal scoop such as a round sphere prepared at the upper end of a base made of a heat insulating material, etc., for example, instead of the above-mentioned supply using a rod-shaped material. A large number of particles may be sequentially rolled on a slide and then continuously supplied to the molten metal particles in the crucible.

As described above, according to the present invention, when producing ultrafine alloy particles of two or more metal materials by the whole gas evaporation method, the metal with the lowest vapor pressure among these materials is used. The material is molten metal in an evaporated state, and the remaining metal material is continuously supplied to this molten metal from the outside.
Both vapors can be generated simultaneously and come into mixed contact with each other,
By controlling the supply rate so that a good population of ultrafine alloy particles is obtained as a whole, it is possible to easily obtain desired ultrafine alloy particles having different alloy composition ratios.

[Brief explanation of the drawing]

FIG. 1 is a partially cut-out side view of an example showing the method and apparatus of the present invention, and FIG. 2 is a graph showing the entire relationship curve between the single-digit feed rate and the composition ratio of ultrafine alloy particles produced. FIG. 3 is a graph showing a relationship curve similar to that of FIG. 2 in another embodiment. (1)... Processing container (2)...
Pot (3)... Inert gas inlet (4).
...Collection tube (5) ... Heating means (
6)...Cooling adhesion plate (101...Metal material supply port a...Metal material for molten metal b...
...Provided money h (Material patent applicant New Technology Development Corporation 1st grade) Kaikai Masaru Kamibuchi 1) Hidetsugu

Claims (1)

[Claims] 1. A method of producing ultrafine particles of two or more alloys having significantly different vapor pressures by evaporation in a sonic gas,
A metal material with the lowest vapor pressure among two or more types of metal materials is prepared in the molten metal in an evaporated state in a processing container, and continuously supplied onto the remaining one or more metal materials. A method for producing ultrafine alloy particles using the evaporation method in gas, which has all the characteristics that we have developed. 2. The production method according to claim 1, wherein the one or more metal materials supplied to the molten metal are solids such as rods or pellets. & At least one of the metal materials supplied to the molten metal has a vapor pressure that is two or more orders of magnitude higher than the vapor pressure of the metal material prepared as the molten metal. Generation method described in. 4. The metal material supplied to the molten metal is in the form of a rod, pellet, etc., and its outer periphery is covered with a metal material that does not produce melting or evaporation noise due to the heat in the processing container. The production method according to claim 1. 5. The production method according to claim 4, wherein the coating metal material is the same metal material used as the molten metal. 6. A bamboo alloy ultrafine particle production method consisting of a heating device, a gold-film sintered treatment container, and a supply port for supplying metal material from the outside.