KR960013893B1 - Method of metal powder - Google Patents

Abstract

Compared with the generally gas-spray method having low efficiency of gas, difficult control of thermodynamic and mechanical properties, agglomeration and surface oxidation of powder, this method employing the principle of solvent extraction provides a excellent facility of control of particle size, a homogeneous metal powder on the shape and the distribution of particle size, and a prevention of contamination and oxidation. The metal powder is produced by the processes of : immersing of rotary bar(5) with blade and impeller in an inorganic solvent(7) of the mixer(2), mixing and emulsifying of liquid metal(10) and the inorganic solvent through the punched suction holes(11) by the high-speed rotating of rotary bar(5) and through pressurization device(4), sedimenting and separating of emulsified mixture by the difference of specific gravity in the precipitator(3), withdrawing of metal powder(1).

Description

Manufacturing method of metal powder

1 is a schematic diagram of a device used in the present invention.

2 is a graph showing the change of the average particle diameter of the metal powder according to the height of the outlet of the mixer and the rotation speed of the motor in the apparatus used in the present invention.

3 is a scanning electron micrograph of a Pb-Sn alloy powder prepared according to the present invention.

The present invention relates to a method for producing a metal powder, and more particularly, to a method for producing a metal powder, which is easy to control the particle size and uniform in shape and particle size distribution, using the principle of a device used for solvent extraction.

In general, there are several methods for producing metal powder. Among them, the spray method is a representative method of directly obtaining a solid powder from a metal liquid phase. Spraying is a method of obtaining a liquid metal by pulverizing it with a second fluid (gas or liquid), or by striking a solid plate at high speed. The mechanical and physical properties of the powders obtained at this time depend on the size of the sprayed powders. In general, however, the smaller the powder is, the more post-treatment the powder must be. That is, it should be possible to prevent contamination and oxidation from the outside. In addition, the shape of the powder must be spherical so that it can be used industrially. Such powders must be spherical in shape to be used industrially. There are many process variables in controlling the size and shape of such powders and there are many difficulties in controlling them. In other words, in the manufacture of metal powder with excellent mechanical properties, the gas sprayer is suitable for mass production, but the efficiency of the gas used in powder production is low, and it is difficult to control the shape and size of the powder, the surface oxidation, and the mass of the powder ( agg1o-meration). There are disadvantages such as difficult control of the thermodynamic and mechanical properties of the powder. In order to provide a method for manufacturing a metal powder with a uniform particle size distribution and easy control of the size and shape of the metal powder produced by supplementing the shortcomings of the gas spraying method, which has been widely used as a method for manufacturing a metal powder. There is an object of the present invention.

In order to achieve the above object, according to the present invention, the blade and the impeller is installed in the above-mentioned inlet perforated at the bottom of the mixer by rotating the rotating rod, which is deposited in an inorganic solvent, which is installed and does not react with the manufactured metal powder. Emulsifying and mixing the liquid metal and the inorganic solvent into the mixer; And precipitating the metal powder and the inorganic solvent and the mixture introduced through a predetermined locating outlet of one side wall of the mixer by the specific gravity difference in the precipitator to recover the metal powder through the powder recovery port, and The excess inorganic solvent is introduced is recycled through the inorganic solvent circuit for reuse to provide a method for producing a metal powder.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 shows a schematic view of an apparatus for carrying out the method for producing a metal powder according to the present invention. This apparatus is supplied with a relatively high temperature mixer (2) serving to emulsify the charged liquid metal (10) and the inorganic solvent (7), and the prepared emulsified mixed liquid to transfer the metal powder (1) to the inorganic solvent ( 7) it can be divided into two parts of sedimenter (3), which is a part of the geothermal zone that is separated and settled. Silicone oil is widely used as the inorganic solvent used in the present invention, but in the case of a high melting point metal such as Al-Si, a salt such as KC1 + LiCl may be used.

In the mixer (2), the inlet (11) drilled in the bottom of the mixer (2) by rotating the rotary rod (5) with blades and impellers attached to the inorganic solvent (7) and rotating at high speed by the rotational force of the motor (M). In addition to raising the liquid metal and the inorganic solvent (oil) sucked through, it also serves to crush the already formed metal powder. At this time, it is preferable that the partition 12 is installed at a portion where the liquid metal and the inorganic solvent meet directly under the suction port 11 so that the liquid metal or the inorganic solvent flows horizontally with each other so as not to invade.

FIG. 1 shows a structure in which the liquid metal 10 is sucked through the suction port 11 punctured at the bottom of the mixer 2, but in another way, for example, the mother alloy is immersed in the mixer 2 in a bulk form. After heating and melting with one, rotating the rotating rod, ② method to pour the liquid metal from the top of the mixer (2), or ③ improve the motor (M) portion of the rotating rod in the form of a pipe and then the liquid metal through the inside Various methods are possible in the supply method of the liquid metal, such as the supply method, without departing from the scope of the present invention.

As the rotating rod 5 continues to rotate, the amount of the solution to be edified by the mixing action of the liquid metal and the oil which is continuously introduced and increased increases, so that the outlet 13 formed at a predetermined position on one side wall of the mixer 2 Through the flow into the low temperature settler (3) without flow. In the precipitator (3), the liquid metal solidifies completely, and the solid metal powder (1) and the inorganic solvent (7) are separated by the specific gravity difference with the inorganic solvent, and a high specific metal powder is precipitated at the bottom of the precipitator. Subsequently, the precipitator 3 is recovered through the powder recovery port 9 provided at the lower part of the other side wall and the inorganic solvent recirculation furnace 8 from the upper part thereof, so that the prepared metal powder is recovered and the inorganic solvent is reused for reuse. Circulated.

Since liquid metal has a high specific gravity, there may be a case in which suction is not sufficiently performed only by the rotational force by the rotating rod. In this case, a separate device capable of charging the liquid metal, for example, a molten liquid metal as shown in FIG. By pressurizing by using a pressurizing device such as a press 4, the liquid metal can be sucked more efficiently.

It is preferable that the volume ratio of the liquid metal and the inorganic solvent sucked through the suction port 11 is 2: 1 or more due to the properties of the powder finally obtained.

On the other hand, it is possible to control the particle size of the final metal powder obtained by appropriately adjusting the height and the size of the outlet 13 of the emulsified liquid constituted in the mixer 2, thereby facilitating the production of fine metal powder. In addition, the characteristics of the powder can also be controlled by operating variables such as the rotational speed rpm of the motor M, the number of blades, or the emulsification time.

Reference numeral 6 denotes a heater for maintaining a predetermined temperature during the production process of the metal powder.

According to the present invention, it is easy to control the particle size of the final powder by selectively adjusting the various operating variables as described above. For example, as shown in FIG. 2, the relationship between the rotation speed (rpm) of the motor and the average particle size of the metal powder according to the height (H) of the outlet of the mixer shows that the larger the rotation speed of the motor, It can be seen that the higher the height of the outlet, the smaller the particle size of the metal powder. 3 is a scanning electron microscope (SEM) photograph of the Pb-Sn alloy powder of the process composition according to the present invention. The metal powder obtained under the same operating conditions has a good particle size distribution, and the formation of satellite powder and the agglomeration of powder are observed. It is not possible to prevent the oxidation of the powder due to the manufacturing process in the inorganic solvent, it is useful for mass production because it can be performed by separating the continuous injection of the liquid metal and the collection of the manufactured metal powder.

In addition, the present invention has been described in the case where the process is carried out by one-to-one engagement of the mixer and the settler, respectively, but may also contribute to powder size control or production line improvement by using multiple mixers in parallel.

Claims (3)

The impeller-attached rotary bar 5 is deposited on the inorganic solvent 7 in the mixer 2 to rotate at high speed, and the liquid metal 10 and the inorganic body are formed through the inlet 11 formed in the bottom of the mixer 2. Suction mixing the solvent (7) to emulsify it; And recovering the metal powder (1) by precipitating and separating the emulsified mixture introduced from the mixer (2) in a precipitator (3). 2. The liquid metal (10) according to claim 1, characterized in that the liquid metal (10) is pressurized using the pressure means (4) together with the rotation of the rotating rod (5) to facilitate the suction of the liquid metal into the mixer (2). How to. The method according to claim 1 or 2, characterized in that the emulsifying step is carried out two or more times by installing two or more mixers (2) in parallel.