WO2013147338A1

WO2013147338A1 - Method for manufacturing oxide dispersion-strengthened platinum-gold alloy powder using dry method

Info

Publication number: WO2013147338A1
Application number: PCT/KR2012/002243
Authority: WO
Inventors: 윤원규; 양승호; 박재성; 김태훈; 연병훈
Original assignee: 희성금속 주식회사
Priority date: 2012-03-27
Filing date: 2012-03-28
Publication date: 2013-10-03
Also published as: KR101321945B1; JP2015516512A; KR20130109348A

Abstract

The present invention relates to a method for manufacturing platinum alloy powder used to manufacture oxide dispersion-strengthened platinum materials. The objective of the present invention is to overcome the disadvantages of existing wet and dry methods for manufacturing platinum alloy powder, such as environmental pollution problems including wastewater treatment due to the use of acids, a complicated manufacturing process, high manufacturing costs, and a long manufacturing time. To this end, the present invention obtains fine and highly-purified platinum alloy powder which is prepared by: manufacturing a platinum alloy ingot by adding an alloy element for a target composition to platinum; manufacturing platinum alloy powder using an environmentally friendly plasma process; obtaining fine and highly-purified platinum alloy powder using and performing heat treatment and classification.

Description

Method for producing oxide-dispersed platinum-gold alloy powder by dry method

Industrial Applicability The present invention provides an oxide dispersion strengthened platinum material which is widely used in places where high strength is required for platinum devices (dissolving devices, crucibles, bushings, etc.) used in glass related industries. The present invention relates to a platinum alloy powder manufacturing method for, in particular, to create a platinum alloy powder using an environmentally friendly plasma method.

Conventionally, oxide dispersion-enhanced platinum alloys having excellent high temperature strength characteristics have been used as materials mainly used in glass-related industries.

In particular, with the growth of the flat panel display industry, the demand for LCD glass has exploded. In addition, the demand for platinum used in LCD manufacturing materials and devices has increased greatly due to the increased demand for high quality glass for LCD. have. Platinum material of several times improved strength is required to manufacture such high-quality glass, and in order to increase the strength of platinum, conventionally, alloys of platinum (Au), rhodium (Rh), and the like are strengthened to solid solution. Although platinum materials have been used a lot, alloy elements used as solid solution strengthening elements are expensive and colored according to alloying components. In recent years, these materials are very inexpensive and have high temperature strength. The trend is being replaced.

As an oxide used for alloying, platinum material in which oxides are formed and dispersed using elements such as zirconium (Zr), samarium (Sm), yttrium (Y), europium (Eu), and hafnium (Hf), which are superior in oxidizing power to platinum. The platinum material containing these oxides has no grain growth and little deformation even when used for a long time at a high temperature of 1200 or more, and recrystallization is hindered by the oxide, resulting in elongated crystal grains. Known.

The present invention relates to a method for producing a platinum-gold alloy powder using a dry method for producing a platinum material dispersed with an oxide, and introduces the world's first environmentally friendly plasma method instead of the conventional dry method using a conventional wet method and vacuum melting. The purpose is to produce an alloy powder of the final high purity through powder production and post-heat treatment.

In order to solve this problem, a platinum alloy ingot is prepared by adding gold, which is a target composition to platinum, as an alloying element, and a platinum-gold alloy powder is prepared by using plasma, followed by atmospheric heat treatment to produce a high purity platinum-gold alloy powder. It aims to do it.

In the present invention, a platinum-gold alloy ingot of a target composition is prepared by adding gold, which is a target composition to platinum, in a vacuum atmosphere or an inert gas (Ar, N ₂ ) atmosphere as an alloying element, and using a thermal plasma, a platinum-gold alloy. To prepare a powder, it is characterized in that the high purity platinum-gold alloy powder for the production of oxide dispersion-enhanced platinum material having uniform properties by removing and classifying impurities in the powder by using a queue treatment.

It is possible to produce fine powder when wet powder is applied, but it is difficult to manage and handle waste liquids because of the long production period and use of strong acid, and it is difficult to control the content of alloying elements.

In addition, the recently known dry method has the advantage that it is easier to control the content than the wet method and to produce a platinum material having a high temperature strength, but the cost is increased due to the complicated processes such as grinding and degassing to prepare powder. And lowering of purity.

However, the present invention, in the production of platinum-gold alloy powder used for the oxide dispersion-enhanced platinum material by introducing an environmentally friendly plasma, rather than the conventional wet and dry method, it is possible to manufacture the platinum alloy powder in a short time, queue processing Through this, there is an advantage that high purity platinum alloy powder can be manufactured. Through this, it is possible to reduce the cost in the production of high purity platinum alloy powder, and to manufacture the oxide dispersion-enhanced platinum material having high strength at high temperature.

1 is a FESEM image of a Pt-Au-Zr powder prepared by plasma.

2 is a FESEM image of the powder after heat treatment of the Pt-Au-Zr powder.

3 is a graph showing the results of particle size analysis on the Pt-Au-Zr powder after plasma and heat treatment.

In the production of platinum-gold alloy powder for the production of oxide dispersion-enhanced platinum material, the vacuum melting method is applied to the preparation of the ingot of the platinum-gold-oxide alloy, and the platinum alloy powder is subjected to the thermal plasma process. In preparing the powder, internal oxidation is performed to prevent initial vaporization of the gold material, a powder is prepared using an environmentally friendly plasma, and a high purity powder is produced through a final heat treatment.

A method of producing a high purity platinum alloy powder for producing an oxide dispersion-enhanced platinum material, comprising: adding a target composition of gold (Au) as an alloying element to pure platinum to produce a platinum alloy ingot; initial vaporization of the gold material In order to prevent the internal oxidation, the step of forming a plasma to produce a platinum alloy powder, and the platinum-gold-oxide alloy powder is subjected to heat treatment to prepare a high purity platinum-gold alloy powder .

Hereinafter, the process steps will be described in detail.

First, a platinum-gold-oxide alloy ingot is prepared by adding an alloying element of the target composition to pure platinum. The content of gold (Au), which is the alloying element added, is characterized in that 3 to 6wt%, the amount of the metal element added as the alloying element for the oxide is characterized in that 0.5wt% to 0.9wt%. If it exceeds 1 wt%, the oxide dispersion strengthening effect of the alloying element is increased, resulting in a decrease in workability. Therefore, the amount of the alloying element and the alloying element is characterized by improving the workability while maximizing the dispersion strengthening effect. In addition, since these elements are superior in oxidizing property to platinum, and when dissolved in the air, it is difficult to control the content of the target composition by oxidation and vaporization, and therefore, it is preferable to prepare the platinum alloy ingot in a vacuum or inert atmosphere.

The prepared platinum alloy ingot is oxidized to the inside and outside of the ingot through an internal oxidation process, and then the ingot is set inside the plasma chamber.

Clean the inside of the chamber before the plasma treatment, set the platinum alloy ingot on the carbon mold inside the chamber, and adjust the distance between the plasma torch and the ingot. As the applicable negative electrode material, molybdenum (Mo), tungsten (W) and platinum may be used, and platinum, which is the same material as that of the raw material, is most preferable for producing a high purity powder. Molybdenum (Mo), tungsten (W), copper (Cu), graphite, and the like can be used as the mold material in which the ingot is set and usable for forming the melt. It is important to maintain high purity and minimize contamination by the mold, and it is important to select a mold that is easy to remove the contamination even if contamination is caused by the mold. To this end, carbon, which is preferably easy to remove, is advantageous, and more preferably, it is most preferable to use a platinum mold that does not affect purity even if contaminated.

Depressurize the inside of the plasma equipment, and form a plasma to produce a powder.

In order to form a plasma, a vacuum system was used to reduce the pressure to a level of 10 ⁻¹ torr, and after adjusting the reaction gas input and the working vacuum, electric power was applied to form a plasma. As the reaction gas used, a mixed gas such as Ar, N ₂ , CH ₄ , Ar + H ₂ , and Ar + N ₂ may be used, but Ar is most preferably used. In order to increase the powder production rate, when N ₂ and H ₂ are partially contained in the Ar gas, the reaction gas content is preferably added at less than 1.5% to 3%. It is preferable to add it, because when it is 1% or less, the effect of increasing the powder production rate cannot be expected, and when it is 5% or more, the possibility of remaining in the powder is high. It is desirable to work at about 45 to 700 torr, because if it is less than 45 torr, it is difficult to directly transfer heat to the platinum alloy ingot, and if it is above 700 torr, the exhaust capacity of the pump may be lowered, which may make it difficult to remove impurities during melting. . Vacuum control is performed using other cooling gases attached to the equipment or by using a vacuum control valve.

When plasma power is increased after plasma formation, a molten metal is formed, and the temperature of the molten metal is increased, so that the molten metal above the vaporization temperature is vaporized and cooled to produce a powder, or the powder is also produced by scattering by the ambient atmosphere and the reaction gas pressure. . At this time, the manufactured power is preferably 15 to 50 kw or less. If the power is 15 kw or less, there is a limitation in the production of scattering powder, and is performed at 50 kw or less in consideration of the stability of the equipment.

In the case of the platinum alloy powder produced by plasma, carbon melting and vaporization also occurs when the molten metal is formed by using a graphite mold. Thus, the carbon powder is removed by heat treatment to obtain a platinum powder of high purity by removing the carbon powder. To obtain a platinum powder having a constant size through classification.

In the case of heat treatment, the atmosphere is preferably an atmosphere or an oxygen atmosphere, in order to utilize a mechanism in which fine carbon is bonded and gasified and removed with oxygen at a high temperature of 500 or more. The heat treatment temperature is preferably 600 to 1200 and 1 to 4 hours. If the temperature is 600 or less and less than 1 hour, the remaining carbon is not likely to be sufficiently removed. If the temperature is 1200 or more and a long time of 4 hours or more, the produced powder is likely to aggregate.

It is possible to control the powder of the desired size using a standard body for the platinum alloy powder from which the carbon component is removed. Powder size control is important for showing uniform characteristics of the oxide dispersion-enhanced platinum material, so it is preferable to consider the powder use yield and the properties of the platinum material.

[실시예 1]Example 1

In order to manufacture Pt-5wt% Au-0.3wt% Zr ingot using a vacuum high frequency induction furnace, ingot 800 gr was prepared by adding 3N5 grade platinum and 4N grade Au 3N grade Zr. For the prepared ingot, Pt-Au-Zr powder was prepared using a plasma equipment.

In the powder manufacturing process, the prepared ingot is oxidized in an internal oxidation furnace, and then the ingot manufactured in the carbon mold is set, and the distance to the plasma torch is adjusted, and the pressure is reduced to 10 ^-2 torr using a vacuum pump attached to the plasma equipment. After the Ar was formed as a reaction gas to form a plasma, a powder was prepared. Table 1 shows the production process conditions of the platinum alloy powder using the plasma.

Table 1

Process item		Process condition-Example
Process item		Tier 1 (Low Power)	Stage 2 (high power)
Applied Plasma Output (kw)		15	50
Gas for plasma	Furtherance	Ar	Ar + N ₂
Gas for plasma	Gas flow rate (L / min)	30	20 (Ar) / 10 (N2)
Other gas flow rate (composition) (L / min)		160 (N2)	160 (N2)

FESEM image analysis of the Pt-Au-Zr powder prepared by the plasma is shown in FIG. Fine powder is also observed in the prepared powder, but coarse powder of several tens of micrometers is also observed (FIG. 1). The powder was prepared by contaminating carbon by the use of graphite mold to produce a black powder. The final platinum alloy powder was prepared by performing a heat treatment at 800 to 2 hours for carbon removal.

In order to confirm the presence or absence of carbon for the powder, the analysis results using EDS and Cabon analyzer before and after heat treatment are shown in Table 2, and the powder image after heat treatment is shown in FIG. 2.

TABLE 2

Item (wt%)	Before heat treatment	After heat treatment
EDS Analysis	60.2	5.2
Carbon analysis	0.157	0.020

It was confirmed that carbon was removed through the air heat treatment, and the final air heat-treated powder was subjected to powder classification using 45 standard bodies. The results of the particle size analysis to determine the powder size are shown in FIG. The final particle size of the final platinum alloy powder prepared by the heat treatment showed a size of 31.3.

As a result of ICP analysis to confirm purity and Zr content of the prepared platinum alloy powder, Au content is 4.35 wt%, Zr content is 0.2162 wt%, total impurity content is 251 ppm, and Pt purity is not less than 3N8. It was possible to manufacture a high purity platinum alloy powder.

The present invention relates to a method for producing a platinum-gold alloy powder using a dry method for producing a platinum material in which oxides are dispersed, and introduces the world's first environmentally friendly plasma method instead of the conventional dry method using a conventional wet method and vacuum melting. The purpose is to make the final high purity alloy powder through powder production and post heat treatment.

Claims

In preparing a high purity platinum alloy powder for producing a dispersion-enhanced platinum material, adding a alloying element of the target composition to pure platinum to prepare a platinum alloy ingot; Performing an internal oxidation heat treatment process on the manufactured ingot; Setting a platinum alloy ingot inside the plasma equipment; Pressure-reducing the inside of the plasma equipment and forming a plasma to prepare a platinum alloy powder; And performing a heat treatment on the platinum alloy powder to prepare a platinum alloy powder of high purity.
The method of claim 1,

The alloying element added to the step of manufacturing the platinum alloy ingot is any one selected from zirconium (Zr), samarium (Sm), yttrium (Y), europium (Eu), hafnium (Hf) oxide dispersion strengthening Method for producing type platinum-gold alloy powder.
The method according to claim 1 or 2,

The amount of alloying elements added to the step of producing the platinum alloy ingot is a method of producing an oxide dispersion-enhanced platinum-gold alloy powder, characterized in that 0.5 wt% to 0.9 wt%.
The method of claim 1,

The material of the mold used in the plasma equipment is any one selected from graphite, copper (Cu), molybdenum (Mo), tungsten (W) or platinum (Pt) oxide-dispersed platinum-gold Method for producing alloy powder.
The method of claim 1,

The material of the electrode used in the plasma equipment is molybdenum (Mo), tungsten (W) or platinum (Pt) any one selected from the production method of the oxide dispersion-enhanced platinum-gold alloy powder.
The method of claim 1,

The reaction gas used in the plasma formation is Ar, H 2 , N 2 , or CH 4 The production method of the oxide-dispersed platinum-gold alloy powder, characterized in that at least one selected from.
The method of claim 1,

The platinum powder prepared after the plasma treatment is heat-treated in an air or oxygen atmosphere to obtain a high purity platinum powder, characterized in that the production method of the oxide-dispersed platinum-gold alloy powder.
The method of claim 7, wherein

The atmospheric heat treatment is a method of producing an oxide dispersion-enhanced platinum-gold alloy powder, characterized in that the heat treatment for more than 4 hours at a temperature of 600 ℃ to 1200 ℃.