JPS62110848A - Rapid cooling apparatus for liquid - Google Patents

Abstract

PURPOSE:To cool rapidly a liquid material having high m.p. by arranging a water cooled metal crucible to hold molten material along with a nozzle made of material having high m.p. just under the crucible. CONSTITUTION:The water cooled metal crucible 1 is arranged against the high speed rotating roll 4 for rapid cooling and the crucible is divided into right and left blocks which are opened and shut freely by bars 6. At just under the crucible 1, the nozzle 3 made of a material having high m.p. such as nitride boron, is arranged. The material 2 to be melted is melted in the crucible 1 previously under pushing condition of both bars 6, and next when the crucible 1 toward right and left is opened by pulling the bars 6, the molten material 2 drops into the nozzle 3. At this time, a lower chamber is exhausted by a vacuum pump 8 and in an upper chamber, gas is introduced. Then, the molten material 2 is injected on the surface of the roll 4 to cool rapidly. In this way, the rapid cooling for the molten material having high m.p. is surely obtained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a liquid quenching method in which a substance is melted and the substance is cooled and solidified at a high cooling rate by injecting it onto the surface of a roll rotating at high speed. Related to Apparatus (Prior Art) Conventionally, this type of liquid quenching apparatus has been developed to obtain a quenched ribbon of an alloy, and the quenched alloy obtained by such an apparatus can be obtained by a solidification method. It has unique states such as an amorphous state and a non-equilibrium phase state that cannot be obtained by other materials, and has been attracting a lot of attention in recent years.

(Problem to be solved by the invention) However, conventional liquid quenching devices are often made for materials with relatively low melting points such as iron-based alloys, and a quartz nozzle is heated by resistance heating or high-frequency heating. Most of them use a heating method. Therefore, the maximum operating temperature is limited by the fire resistance of quartz, and is 1200 to 1.
The limit is about 300°C. Also, if the temperature increases, contamination of the sample may occur due to reaction with quartz. Even if the material of the nozzle is changed from quartz to other ceramics, it will still be 2,000 yen at most considering the heat resistance, reactivity, etc.
The limit is around ℃.

An object of the present invention is to solve the above-mentioned problems and provide a liquid quenching device that can be used even with high melting point substances having a melting point of 2000° C. or higher.

(Means for Solving the Problems) The present invention provides a liquid quenching device comprising a substance dissolving device and a roll that rotates at high speed and cools and solidifies the dissolved substance at a high cooling rate. This is a liquid quenching device equipped with a metal crucible and a nozzle made of a high-melting point substance placed directly below the crucible.

The liquid quenching device according to the present invention melts the substance in a water-cooled metal crucible, so that the temperature at 2000°C
Even if the above-mentioned high melting point substance is melted, almost no reaction occurs between it and the crucible metal.

This is because if the crucible metal is sufficiently water-cooled, even if high-temperature molten metal comes into contact with it, the temperature of the crucible metal is too low to cause an alloying reaction.

The material of the crucible metal is preferably a material with high thermal conductivity in order to increase the water cooling effect. In addition, substances with high melting points are also suitable from the viewpoint of being difficult to react. −
For example, copper and silver.

Alternatively, alloys thereof, tungsten, molybdenum, etc. can be considered.

In addition, melting methods include arc melting, plasma melting,
Well known methods such as electron beam melting, laser beam melting, etc. can be used.

The sample substance dissolved in this way is dropped into a nozzle made of a high-melting point material, and is sprayed from the nozzle opening onto the surface of the silo roll, becoming a quenched ribbon. At this time, it is passed through the nozzle opening. The reason is to obtain a uniform and continuous quenched ribbon by forming a stable flow of melt. If the molten material were to fall directly onto the roll surface without passing through the nozzle orifice, only a non-uniform and discontinuous ribbon would be obtained.

Also, since the molten substance and the nozzle come into contact at this time, reactions between the two become a problem, but if the nozzle is made of a high melting point material such as boron nitride, graphite, or magnesium oxide, the contact time is extremely short. Because of this, there is little reaction between the two.

As described above, in the liquid quenching device according to the present invention, when the part for dissolving a substance and the nozzle part are separated, K.
Melting substances with a high melting point of over 1,000℃ without contamination.
This makes it possible to obtain a uniform and continuous quenched ribbon by spraying.

(Example) A configuration diagram of an embodiment of the present invention is shown in Fig. 1. In the figure, 1 is a water-cooled metal crucible, 2 is a sample material, 3 is a nozzle made of a high melting point substance, and 4 is a rapidly cooling 5 is a dissolving means. Rubba 1 is divided into left and right blocks,
It can be opened and closed to the left and right using the rod 6. Therefore, when the sample 2 is dissolved with the rod 6 pushed inward and the rear rod 6 is pulled outward, Ruwa 1 will move left and right. Open,
The sample 2 falls into the nozzle 3 due to gravity. At that time, if gas is introduced into the upper chamber from the gas introduction lower and the lower chamber is evacuated by the vacuum pump 8, there will be no gap between the upper and lower chambers. Due to the pressure difference, sample 2
is ejected from the nozzle 3 onto the surface of the roll 4 and becomes a quenched ribbon.

Next, an example of fabrication of a quenched ribbon using the apparatus alif having the first configuration will be described. First, water-cooled copper was used as Ru 1, and boron nitride was used as the nozzle 3. The hole diameter of the nozzle was 0.7 mm. The roll 4 was made of copper and had a diameter of 250 mm and was rotated at a speed of 600 rpm. Further, as the melting device 5, a plasma torch was used. As sample 2, Nb was used. The melting point is approximately 2500°C.

After setting the sample as shown in Fig. 1, the upper chamber is opened by the gas introduction lower while introducing gas at approximately 0.7 m.
Maintaining an Ar atmosphere at atmospheric pressure, the lower chamber was evacuated by a rotary pump 8, the sample was melted by a plasma torch 90, and the rod 6 was pulled outward to open the brim to the left and right. fell into the
Most of the sample was sprayed onto the surface of the roll from the nozzle opening, and after the opening formed a long, uniform ribbon with a width of about 1 mm and a thickness of about 30 μm, nozzle 3 was taken out and examined. Although the sample was slightly solidified and adhered to the inner wall, the adhesion was not that strong and could be easily peeled off, and as a result of examining the interface, it was found that almost no reaction between the nozzle and the sample occurred. Furthermore, when the obtained Nb ribbon was examined for impurities, it matched the analysis value of the raw material within the margin of error, and no evidence of contamination due to liquid quenching was observed.

(Effects of the Invention) As explained in detail above, the liquid quenching device according to the present invention can easily perform liquid quenching of a substance with a high melting point of 2000°C or higher, and the effect is large.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a liquid quenching device of the present invention. In the figure, 1 is a water-cooled metal crucible;
2 is a sample substance, 3 is a nozzle made of a high melting point substance, 4 is a rapid cooling roll, 5 is a substance dissolving device, 6 is a rod for opening and closing the crucible, and 7 is a gas inlet.

Claims (2)

[Claims] (1) A liquid quenching device equipped with a substance melting device and a roll that rotates at high speed and cools and solidifies the dissolved substance at a high cooling rate, including a water-cooled metal crucible that holds the substance, and a water-cooled metal crucible that holds the substance; A liquid quenching device characterized by comprising a nozzle made of a high melting point substance placed directly below the nozzle. (2) The liquid quenching device according to claim 1, wherein the crucible has a structure in which its bottom can be opened and closed.