WO2021167205A1 - Method for improving flowability of powder, and method for producing powder having improved flowability - Google Patents

Abstract

The purpose of the present invention is to provide: a method for improving the flowability of a powder, in particular a metal or alloy powder produced through gas atomization; a method for producing a powder having improved flowability; and a powder having improved flowability produced thereby. To this end, the present invention provides a method for improving the flowability of a powder, the method comprising the steps of: preparing a powder by gas atomization using, as a raw material, a metal having a diffusion coefficient greater than that of nickel (Ni), or an alloy based on said metal; and heat-treating the prepared powder in a temperature range of 20-70% of the melting point of the raw material. According to the present invention, there are advantages in that a powder can be produced in large quantities through gas atomization, and powders of various metals can be produced. In addition, there is an effect that the produced powder has improved flowability despite being produced through gas atomization, and thus can be applied to various applications such as 3D printing.

Description

Method for improving the flowability of powder and manufacturing method for powder with improved flowability

The present invention relates to a method for improving the fluidity of a powder, a method for manufacturing a powder having improved fluidity, and a powder with improved fluidity produced thereby.

Metal powder has no segregation due to rapid solidification, fine grains, and controllable porosity according to processing methods. The field of application is steadily increasing.

In relation to the production of such metal powder, Republic of Korea Patent Registration No. 10-0800505 "Metal powder manufacturing apparatus" is a metal melting tank formed with an orifice for discharging molten metal at the bottom; a vibration transmission rod for refining the molten metal by transmitting the vibration generated from the vibration generating mechanism to the molten metal inside the melting tank; a high-pressure gas storage tank accommodating the high-pressure gas ejected into the molten metal droplets through a supply tube in order to further refine the molten metal droplets discharged from the melting tank; and a metal powder spray tank that receives and cools the molten metal droplets that are refined and discharged by the high-pressure gas, so that the production of fine spherical metal powder having an average particle diameter of 20 μm or less can be stably and inexpensively performed, and MIM metal We are proposing technologies for practical use of powders and metal powders for electronic products.

Registration No. 10-1096734, "Spherical alloy powder and its manufacturing method" is one of rapid solidification (RSP), in the case of the conventional gas atomization process, by melting the alloy raw material of the target composition into a crucible and then in the chamber. Unlike producing fine powder by spraying and cooling high-pressure gas with an annular spray nozzle, the semi-liquid particles sprayed by the annular spray nozzle collide with the inside of the water-cooled cylindrical cooling roller rotating at high speed again to form secondary It is possible to obtain a more homogeneous microstructure by reducing micro-segregation by increasing the cooling effect of the molten alloy by recovering the alloy powder by cooling with are doing

Korean Patent Laid-Open Publication No. 2001-0011544 "Method for producing particulate powder such as powder for cream solder using ultrasonic waves and device therefor" is a method for reducing molten substances into small It is sprayed with droplets, and the sprayed small droplets are cooled to solidify, but the powder particle size can be adjusted by varying the frequency of ultrasonic waves. The flow rate is sprayed on the ultrasonic horn to produce powder for cream solder, and the spraying step is dropped onto the ultrasonic horn vibrating in the range of 20 to 44 kHz in an inert gas atmosphere, so that good quality cream solder powder can be continuously manufactured in large quantities. technology is proposed for

On the other hand, Laid-Open Patent Publication No. 10-2007-0105256 "Metal powder manufacturing apparatus, metal powder and compact" is a supply unit (tundish) for supplying molten metal, a liquid ejection unit provided below the supply unit, and liquid ejection It has a nozzle and a cylindrical body provided below the part, the nozzle has an orifice for jetting a liquid jet (second liquid), and when the dispersion liquid collides with this liquid jet, the propagation direction of the dispersion liquid is forcibly changed. is proposing

In general, mass production of metal powder manufacturing uses an atomizer device, and is divided into a gas atomizer method and a water atomizer method.

In this case, the water spray atomizer device may be divided into a method of spraying only pure water or a mixture of water and gas. The water atomizer method is similar to the gas atomizer method in its operation method and the break-up theoretical model of droplets, but the difference is that the liquid of water is used instead of the gas which is a gas for the transfer of kinetic energy to break the droplets. There is this.

Therefore, since the water atomizer device injects high-density water instead of gas, it has the advantage of generating relatively large kinetic energy and producing up to 1 μm-sized metal powder, but using water instead of inert gas It has limitations in oxidation of phosphorus metal powder and post-processing problems.

However, in the case of metal powder manufactured using the above gas atomizer, the flowability of the powder is greatly reduced because the surface is rough. There is a problem that it does not proceed smoothly.

On the other hand, when the powder is manufactured through the plasma process, there is no problem in applying it to the application field due to the excellent fluidity of the powder, but there is a problem that it takes a lot of manufacturing time due to the nature of the process. It is difficult to manufacture, and there is a problem in that it is not suitable for applications requiring various metal powders.

Accordingly, the inventors of the present invention can mass-produce various kinds of metal powders by manufacturing powders using a gas atomizer, and completed the present invention by conducting research on improving the flowability of the powders to be manufactured.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for improving the flowability of a powder, particularly a metal or alloy powder produced by gas atomization, a method for producing a powder having improved flowability, and a powder with improved flowability produced thereby.

To this end, the present invention

manufacturing a powder by gas atomization using a metal having a diffusion coefficient greater than that of nickel (Ni) or an alloy having the same as a base metal as a raw material; and

performing heat treatment on the prepared powder in a temperature range of 20% to 70% based on the melting point of the raw material;

It provides a method of improving the flowability of a powder comprising a.

Also, the present invention

manufacturing a powder by gas atomization using a metal having a diffusion coefficient greater than that of nickel (Ni) or an alloy having the same as a base metal as a raw material; and

performing heat treatment on the prepared powder in a temperature range of 20% to 70% based on the melting point of the raw material;

It provides a method for producing a powder with improved fluidity comprising a.

Furthermore, the present invention

It provides a powder with improved flowability, which is prepared by the above method and has a hall flow value of 10 to 70 s/50 g of the prepared powder.

According to the present invention, the powder can be produced in large quantities by manufacturing the powder through gas atomization, and there is an advantage that powders of various metals can be manufactured. In addition, despite the production through gas atomization, The flowability of the manufactured powder is improved, and there is an effect that it can be applied to various applications such as 3D printing.

1 is a schematic diagram and a photograph of an apparatus for measuring the flow of powder in the present invention,

2 is a graph showing the difference in fluidity according to the heat treatment temperature for the mold steel powder,

3 is a graph showing the difference in fluidity according to the heat treatment atmosphere for the mold steel powder,

4 is a graph showing the difference in flowability according to heat treatment temperature for SUS316L alloy powder, and

5 is a graph showing whether the flowability is improved when heat treatment is performed on IN718 alloy powder.

In the present invention, the term 'base metal' refers to a metal that occupies the largest percentage by weight in an alloy.

the present invention

manufacturing a powder by gas atomization using a metal having a diffusion coefficient greater than that of nickel (Ni) or an alloy having the same as a base metal as a raw material; and

performing heat treatment on the prepared powder in a temperature range of 20% to 70% based on the melting point of the raw material;

It provides a method of improving the flowability of a powder comprising a.

Hereinafter, the flow improvement method of the present invention will be described in detail for each step.

The method for improving the flowability of powder of the present invention includes preparing a powder by gas atomization using a metal having a higher diffusion coefficient than nickel (Ni) or an alloy using the same as a base metal as a raw material.

In general, when a metal or alloy powder is manufactured by a gas atomization method, for example, the advantage of being able to produce a large amount of powder compared to the case of manufacturing through plasma treatment, and the advantage of being able to manufacture powder of various metals However, the flowability of the powder to be manufactured is low, which causes a problem in application to applications such as 3D printing. The present invention targets the powder produced by the gas atomization method as described above, and particularly, the powder with low flowability produced by the gas atomization method.

On the other hand, in the method for improving the flowability of the present invention, the step of producing a powder through gas atomization is performed by gas atomization using a metal having a higher diffusion coefficient than nickel (Ni) or an alloy using the same as a base metal as a raw material. characterized in that it is manufactured. In the case of nickel or a metal having a lower diffusion coefficient than this or an alloy containing the same, the flowability of the powder is not improved even if heat treatment is performed after the powder is manufactured.

Specifically, the metal having a higher diffusion coefficient than nickel is preferably one selected from the group consisting of copper (Cu), magnesium (Mg), aluminum (Al), titanium (Ti), and iron (Fe). When a powder is prepared by gas atomization using the above metals or an alloy having the same as a base metal as a raw material, and then heat treatment is performed, flowability is improved.

In the case of an alloy as a raw material for gas atomization in the method of the present invention, a metal having a higher diffusion coefficient than nickel is used as the base metal, and it is preferable to include the base metal in an amount of 50% by weight or more based on the total weight of the alloy. When a metal having a higher diffusion coefficient than nickel is included in an amount of less than 50% by weight based on the total weight of the alloy, the flowability may not be improved through heat treatment.

Gas atomization in the method of the present invention may be performed under conditions of a melting point temperature of a raw material to a melting point temperature + 500 °C and a gas injection pressure of 10 to 100 bar. When gas atomization is performed under the above conditions, a large number of powders can be produced in a short time. However, in the case of such preparation, the surface roughness of the powder is greatly increased, and there is a problem in that the flowability of the powder is reduced. However, since the present invention improves the flowability of the powder by performing heat treatment on the powder thus prepared, as a result, there is an advantage that a powder having excellent flowability can be mass produced in a short time.

The method for improving the flowability of powder of the present invention includes performing heat treatment on the powder prepared through the above step at a temperature ranging from 20% to 70% based on the melting point of the raw material. If the temperature of the heat treatment is less than 20% based on the melting point of the raw material, there is a problem that the flowability of the powder is not sufficiently improved. There is a problem that the powder cannot be used in the field of application. In addition, the heat treatment temperature is more preferably performed in a temperature range of 30% to 50% based on the melting point of the raw material in terms of preventing oxidation of the powder while improving the flowability.

In addition, the heat treatment is preferably carried out in one type of environment selected from the group consisting of argon, nitrogen, hydrogen, and nitrogen and hydrogen environment. If the heat treatment is performed in a different environment, there may be a problem in that the metal powder is oxidized.

The method for improving the flowability of the powder of the present invention is characterized in that the hall flow value of the powder produced therethrough is improved to 10 to 70 s/50g. By improving the hole flow value of the powder as in the above range by the method of the present invention, when the powder is applied to an application field such as 3D printing, there is an effect that the process of the application field can be smoothly performed. If the hole flow value exceeds 70 s/50g, for example, if the powder is applied to 3D printing, the powder may not be uniformly applied in the printing process, so that the density and mechanical properties of the molded body are deteriorated. can

The flowability improvement method of the powder of the present invention is a method of improving the flowability of powders with low fluidity produced through gas atomization. While it can be produced as a powder, there is an effect of improving the flowability of the prepared powder.

Also, the present invention

manufacturing a powder by gas atomization using a metal having a diffusion coefficient greater than that of nickel (Ni) or an alloy having the same as a base metal as a raw material; and

performing heat treatment on the prepared powder in a temperature range of 20% to 70% based on the melting point of the raw material;

It provides a method for producing a powder with improved fluidity comprising a.

Hereinafter, the manufacturing method of the present invention will be described in detail for each step.

The method for producing a powder having improved flowability of the present invention includes a step of preparing a powder by gas atomization using a metal having a diffusion coefficient greater than that of nickel (Ni) or an alloy having the same as a base metal as a raw material.

In general, when a metal or alloy powder is manufactured by a gas atomization method, for example, the advantage of being able to produce a large amount of powder compared to the case of manufacturing through plasma treatment, and the advantage of being able to manufacture powder of various metals However, the flowability of the powder to be manufactured is low, which causes a problem in application to applications such as 3D printing. The present invention targets the powder produced by the gas atomization method as described above, and particularly, the powder with low flowability produced by the gas atomization method.

On the other hand, in the powder manufacturing method of the present invention, the step of manufacturing the powder through gas atomization is performed by gas atomization using a metal having a larger diffusion coefficient than nickel (Ni) or an alloy using the same as a base metal as a raw material. characterized in that it is manufactured. In the case of nickel or a metal having a lower diffusion coefficient than this or an alloy containing the same, the flowability of the powder is not improved even if heat treatment is performed after the powder is manufactured.

Specifically, the metal having a higher diffusion coefficient than nickel is preferably one selected from the group consisting of copper (Cu), magnesium (Mg), aluminum (Al), titanium (Ti), and iron (Fe). When the powder is manufactured by gas atomization using the above metals or an alloy having the same as a base metal as a raw material, and then heat treatment is performed, there is an effect that a powder having improved fluidity can be manufactured.

In the case of an alloy as a raw material for gas atomization in the method of the present invention, a metal having a higher diffusion coefficient than nickel is used as the base metal, and it is preferable to include the base metal in an amount of 50% by weight or more based on the total weight of the alloy. When a metal having a higher diffusion coefficient than nickel is included in an amount of less than 50% by weight based on the total weight of the alloy, the flowability may not be improved through heat treatment.

In the method of the present invention, gas atomization may be performed under conditions of a melting point temperature to a melting point temperature of the raw material + 500 °C and a gas injection pressure of 10 to 100 bar. When gas atomization is performed under the above conditions, a large number of powders can be produced in a short time. However, in the case of such preparation, the surface roughness of the powder is greatly increased, and there is a problem in that the flowability of the powder is reduced. However, since the present invention improves the flowability of the powder by performing heat treatment on the powder thus prepared, as a result, there is an advantage that a powder having excellent flowability can be mass produced in a short time.

The method for producing powder with improved fluidity of the present invention includes performing heat treatment on the powder prepared through the above steps in a temperature range of 20% to 70% based on the melting point of the raw material. If the temperature of the heat treatment is less than 20% based on the melting point of the raw material, there is a problem that the flowability of the powder is not sufficiently improved. There is a problem that the powder cannot be used in the field of application. In addition, the heat treatment temperature is more preferably performed in a temperature range of 30% to 50% based on the melting point of the raw material in terms of preventing oxidation of the powder while improving the flowability.

In addition, the heat treatment is preferably carried out in one type of environment selected from the group consisting of argon, nitrogen, hydrogen, and nitrogen and hydrogen environment. If the heat treatment is performed in a different environment, there may be a problem in that the metal powder is oxidized.

The method for producing a powder having improved flowability of the present invention is characterized in that the powder produced through this has a hall flow value of 10 to 70 s/50g. The powder produced by the method of the present invention has a hole flow value within the above range, and thus, when the powder is applied to an application field such as 3D printing, there is an effect that the application field process can be smoothly performed. If the hole flow value exceeds 70 s/50g, for example, if the powder is applied to 3D printing, the powder may not be uniformly applied in the printing process, so that the density and mechanical properties of the molded body are deteriorated. can

The alloy used in the manufacturing method of the present invention preferably contains the base metal in an amount of 50% by weight or more based on the total weight of the alloy. When a metal having a higher diffusion coefficient than nickel is included in an amount of less than 50% by weight based on the total weight of the alloy, the flowability may not be improved through heat treatment.

The method for manufacturing powder with improved fluidity of the present invention is a method for manufacturing powder with improved fluidity while manufacturing powder through gas atomization. Since powder is manufactured through gas atomization, various metal or alloy powders are used While it can be mass-produced, there is an effect of improving the flowability of the manufactured powder.

Further, the present invention provides a powder with improved flowability, which is manufactured by the above method and has a hall flow value of 10 to 70 s/50 g of the prepared powder.

If the hole flow value exceeds 70 s/50g, for example, if the powder is applied to 3D printing, the powder may not be uniformly applied in the printing process, so that the density and mechanical properties of the molded body are deteriorated. can

In this case, the powder having improved fluidity may be one type of metal powder selected from the group consisting of copper (Cu), magnesium (Mg), aluminum (Al), titanium (Ti), and iron (Fe).

Since the powder of the present invention is manufactured through the gas atomization method, it can be mass-produced in a short time and, unlike the plasma process, which can produce only limited metal powders such as titanium, various types of metal powders are produced. While it can be manufactured, there is an advantage that the flowability is improved, and it can be applied to a variety of applications.

Hereinafter, the present invention will be described in more detail through Examples, Comparative Examples and Experimental Examples. However, the following Examples, Comparative Examples, and Experimental Examples are only intended to illustrate and specifically describe the contents of the present invention, and are not intended to limit and interpret the scope of the present invention by the following contents.

<Example 1>

Production of powder using mold steel

A powder was prepared by the following method using a mold steel having the composition shown in Table 1 below.

C	Cr	Mo	V	Nb	Fe
0.9	5.3	2.8	0.4	1.2	Bal.

The alloy ingot of the above composition was heated to a temperature of 1650 ° C using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers.

The obtained powder was heat-treated at a temperature of 200° C. and a heat treatment atmosphere of _{N 2} +H _{2 for 1 hour.}

<Example 2>

Production of powder using mold steel

A powder was prepared by the following method using a mold steel having the composition shown in Table 1.

The alloy ingot of the above composition was heated to a temperature of 1650 ° C using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers.

The obtained powder was heat-treated at a temperature of 300° C. and a heat treatment atmosphere of _{N 2} +H _{2 for 1 hour.}

<Example 3>

Production of powder using mold steel

A powder was prepared by the following method using a mold steel having the composition shown in Table 1.

The alloy ingot of the above composition was heated to a temperature of 1650 ° C using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas spray pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers.

The obtained powder was heat-treated at a temperature of 400° C. and a heat treatment atmosphere of _{N 2} +H _{2 for 1 hour.}

<Example 4>

Production of powder using mold steel

A powder was prepared by the following method using a mold steel having the composition shown in Table 1.

The alloy ingot of the above composition was heated to a temperature of 1650 ° C using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers.

The obtained powder was heat-treated at a temperature of 600° C. and a heat treatment atmosphere of _{N 2} +H _{2 for 1 hour.}

<Example 5>

Production of powder using mold steel

A powder was prepared by the following method using a mold steel having the composition shown in Table 1.

The alloy ingot of the above composition was heated to a temperature of 1650 ° C using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers.

The obtained powder was heat-treated at a temperature of 600° C. and a heat treatment atmosphere of _{N 2 for 1 hour.}

<Example 6>

Production of powder using mold steel

A powder was prepared by the following method using a mold steel having the composition shown in Table 1.

The alloy ingot of the above composition was heated to a temperature of 1650 ° C using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers.

The obtained powder was heat-treated at a temperature of 600° C. and a heat treatment atmosphere of _{H 2 for 1 hour.}

<Example 7>

Production of powder using mold steel

A powder was prepared by the following method using a mold steel having the composition shown in Table 1.

The alloy ingot of the above composition was heated to a temperature of 1650 ° C using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas spray pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers.

The obtained powder was heat-treated at a temperature of 600° C. and an Ar heat treatment atmosphere for 1 hour.

The heat treatment conditions of Examples 1 to 7 are summarized in Table 2 below.

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7
Heat treatment temperature (℃)	200	300	400	600	600	600	600
heat treatment atmosphere	N 2 +H 2	N 2 +H 2	N 2 +H 2	N 2 +H 2	N 2	H 2	Ar

<Example 8>

Preparation of powder using STS316L

A powder was prepared by the following method using a commercial STS316L alloy.

Commercial STS316L alloy was heated to a temperature of 1650 °C using induction inside a gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was heat-treated at a temperature of 400° C. and an Ar atmosphere for 1 hour.

<Example 9>

Preparation of powder using STS316L

A powder was prepared by the following method using a commercial STS316L alloy.

Commercial STS316L alloy was heated to a temperature of 1650 °C using induction inside a gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was heat-treated at a temperature of 500° C. and an Ar atmosphere for 1 hour.

<Example 10>

Preparation of powder using STS316L

A powder was prepared by the following method using a commercial STS316L alloy.

Commercial STS316L alloy was heated to a temperature of 1650 °C using induction inside a gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was heat-treated at a temperature of 600° C. and an Ar atmosphere for 1 hour.

<Example 11>

Preparation of powder using STS316L

A powder was prepared by the following method using a commercial STS316L alloy.

Commercial STS316L alloy was heated to a temperature of 1650 °C using induction inside a gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was heat-treated at a temperature of 700° C. and an Ar atmosphere for 1 hour.

<Example 12>

Preparation of powder using STS316L

A powder was prepared by the following method using a commercial STS316L alloy.

Commercial STS316L alloy was heated to a temperature of 1650 °C using induction inside a gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was heat-treated at 800° C. and Ar atmosphere for 1 hour.

Table 3 summarizes the heat treatment conditions of Examples 8 to 12.

	Example 8	Example 9	Example 10	Example 11	Example 12
Heat treatment temperature (℃)	400	500	600	700	800
heat treatment atmosphere	Ar	Ar	Ar	Ar	Ar

<Examples 13 to 16>

Using a raw material having an alloy composition of Fe60Co15Ni15Cr10, a powder was prepared by the following method.

The raw material was heated to a temperature of 1650° C. using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was subjected to heat treatment at 600° C. and argon atmosphere for 1 hour.

<Example 14>

Using a raw material having an alloy composition of Fe55Co18Cr12.5Ni7Mo7.5, a powder was prepared by the following method.

The raw material was heated to a temperature of 1700° C. using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was subjected to heat treatment at 600° C. and argon atmosphere for 1 hour.

<Example 15>

Using a raw material having an alloy composition of Fe62Ni11Cr13Al14, a powder was prepared by the following method.

The raw material was heated to a temperature of 1650° C. using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was subjected to heat treatment at 600° C. and argon atmosphere for 1 hour.

<Example 16>

A powder was prepared by the following method using a raw material having an alloy composition of Ti-6Al-4V.

The raw material was heated to a temperature of 1830 °C using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was subjected to heat treatment at 600° C. and argon atmosphere for 1 hour.

The alloy compositions of Examples 13 to 16 are summarized in Table 4 below.

	Example 13	Example 14	Example 15	Example 16
alloy composition	Fe60Co15Ni15Cr10	Fe55Co18Cr12.5Ni7Mo7.5	Fe62Ni11Cr13Al14	Ti-6Al-4V

<Example 17>

The alloy ingot of AlSi10Mg composition was heated to a temperature of 770 ° C using induction inside the gas atomizer, and the molten metal was finely crushed with argon gas while spraying it through the gas atomizer at a gas spray pressure of 70 bar to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was heat-treated at 200° C. and under argon atmosphere for 1 hour.

<Comparative Examples 1 to 7>

A powder was prepared by the following method using the ingot of the composition shown in Table 5 below.

comparative example	Furtherance
One	The mold steel composition
2	The STS316L composition
3	Composition of Example 13
4	Composition of Example 14
5	Composition of Example 15
6	Composition of Example 16
7	Composition of Example 17

1650 °C (Comparative Example 1), 1650 °C (Comparative Example 2), 1650 °C (Comparative Example 3), 1700 °C (Comparative Example 4), 1650 °C for each of the raw materials in Table 5 using induction inside the gas atomizer (Comparative Example 5), 1830 ℃ (Comparative Example 6), 770 ℃ (Comparative Example 7) was heated to a temperature, which was sprayed with a gas atomizing pressure of 70 bar through a gas atomizer while crushing the molten metal finely with argon gas to obtain a powder prepared. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. Heat treatment was not performed on the obtained powder.

<Comparative Examples 8 to 11>

The IN718 nickel-based alloy ingot was heated to a temperature of 1580 ° C using induction inside the gas atomizer, and the molten metal was crushed with argon gas while spraying it at a gas atomization pressure of 70 bar through the gas atomizer to prepare a powder. The cooled powder was removed by using a sieve to remove a powder having a size greater than 45 micrometers and an aerosol classifier to remove a powder smaller than 20 micrometers to finally obtain a powder having a size of 20 to 45 micrometers. The obtained powder was heat-treated in an argon atmosphere at 600 °C (Comparative Example 8), 800 °C (Comparative Example 9), and 1000 °C (Comparative Example 10) for 1 hour. Comparative Example 11 was obtained in which no heat treatment was performed on the obtained powder.

<Experimental example>

Fluidity Analysis of Powders

Fluidity analysis of the powder was performed according to ASTM B 213.

Specifically, 50 g of each of the powders prepared in Examples 1 to 17 and Comparative Examples 1 to 11 were prepared, and the powder was introduced by blocking the bottom of the funnel of a hall flow meter as shown in FIG. 1 . The time was started as the lower membrane was opened, stopped and the time recorded when the powder had run out. The results are shown in Table 6 and FIGS. 2 to 5 .

Example	Fluidity (s/50g)
One	23.3
2	14.41
3	14.65
4	15.76
5	15.08
6	14.89
7	14.48
8	16.16
9	15.69
10	15.68
11	15.08
12	16.64
13	13.96
14	13.90
15	17.01
16	25.09
17	68.81
comparative example
One	not measurable
2	not measurable
3	not measurable
4	not measurable
5	not measurable
6	not measurable
7	not measurable
8	not measurable
9	not measurable
10	not measurable
11	not measurable

According to Table 6 and FIGS. 2 to 5 , the following facts can be confirmed.

In the case of all the metals or alloys subject to the test, if the heat treatment was not performed, the flowability was very poor, so measurement was impossible.

Metals or alloys with a higher diffusion coefficient than nickel have improved fluidity through the heat treatment process.

In the case of nickel, the flowability of the powder did not improve no matter how much the heat treatment temperature was increased.

According to the method of the present invention through the above experimental results, it is possible to greatly improve the flowability of the powder without risk of oxidation while mass-producing various types of powder through gas atomization, so that the manufactured powder can be used in various applications. There is an effect that can be applied.

Claims (15)

1. manufacturing a powder by gas atomization using a metal having a diffusion coefficient greater than that of nickel (Ni) or an alloy having the same as a base metal as a raw material; and

   performing heat treatment on the prepared powder in a temperature range of 20% to 70% based on the melting point of the raw material;

   A method of improving the flowability of a powder comprising a.
2. The method of claim 1, wherein the metal having a diffusion coefficient greater than that of nickel is one selected from the group consisting of copper (Cu), magnesium (Mg), aluminum (Al), titanium (Ti), and iron (Fe). A method for improving the flowability of powders.
3. The method of claim 1, wherein the alloy contains 50% by weight or more of the base metal based on the total weight of the alloy.
4. The method of claim 1, wherein the gas atomization is performed in a temperature range of a melting point temperature of a raw material to a melting point temperature + 500°C.
5. The method of claim 1, wherein the gas atomization is performed under a gas injection pressure of 10 to 100 bar.
6. The method of claim 1, wherein the heat treatment is performed in a temperature range of 30% to 50% based on the melting point of the raw material.
7. The method of claim 1, wherein the heat treatment is performed in one type of environment selected from the group consisting of argon, nitrogen, hydrogen, and a nitrogen and hydrogen environment.
8. The method according to claim 1, wherein the powder flowability improving method is to improve the powder's hall flow value from 10 to 70 s/50g.
9. manufacturing a powder by gas atomization using a metal having a diffusion coefficient greater than that of nickel (Ni) or an alloy having the same as a base metal as a raw material; and

   performing heat treatment on the prepared powder in a temperature range of 20% to 70% based on the melting point of the raw material;

   A method for producing a powder with improved fluidity comprising a.
10. The method of claim 9, wherein the metal having a diffusion coefficient greater than that of nickel is one selected from the group consisting of copper (Cu), magnesium (Mg), aluminum (Al), titanium (Ti), and iron (Fe). A method for producing a powder with improved fluidity.
11. The method of claim 9, wherein the heat treatment is performed in a temperature range of 30% to 50% based on the melting point of the raw material.
12. 10. The method of claim 9, wherein the heat treatment is performed in one environment selected from the group consisting of argon, nitrogen, hydrogen, and a nitrogen and hydrogen environment.
13. [10] The method of claim 9, wherein the alloy contains 50% by weight or more of the base metal based on the total weight of the alloy.
14. 10. A powder prepared by the method of claim 9, wherein the powder has a hall flow value of 10 to 70 s/50g.
15. 15. The method of claim 14, wherein the powder with improved fluidity is one type of metal powder selected from the group consisting of copper (Cu), magnesium (Mg), aluminum (Al), titanium (Ti), and iron (Fe). Powder with improved fluidity, characterized in that.

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