KR101359719B1 - Method of manufacturing a powder of platinum-ruthenium alloys - Google Patents

Abstract

The present invention relates to a method for producing an oxide dispersion-reinforced platinum-ruthenium alloy powder which requires high strength and desorption with glass in the platinum apparatus used for the high quality glass manufacturing apparatus. Many, problems such as acid treatment occurs, and is designed to improve the disadvantage that the manufacturing time also takes several days.
In order to solve this problem, platinum alloy ingot is added to platinum to form a target composition of ruthenium and oxide dispersion strengthening, heat treatment is performed on the prepared ingot, an oxide layer is formed, and a certain amount of oxygen is easily added after plasma formation. It is an object to produce a platinum-ruthenium alloy powder.

Description

Method of manufacturing a powder of platinum-ruthenium alloys

The present invention provides the production of oxide dispersed strengthening platinum materials, which are widely used in places where high strength is required for platinum devices (melting equipment, crucibles, bushings, etc.) used for high quality glass manufacturing apparatus. The present invention relates to a method for preparing a platinum-ruthenium alloy powder, and more particularly, to a method of preparing a platinum-ruthenium alloy powder using a dry method after manufacturing a platinum-ruthenium ingot.

Platinum is a face-centered cubic structure that is easy to process at room temperature and high temperature, has a high melting point (1780 ℃), chemical stability at high temperature, resistance to oxidation and volatility, and corrosion resistance to acids and chemicals. Although the material is expensive, it has been used for various purposes. In particular, with the recent growth of the LCD industry, it is widely used for materials and devices for manufacturing high-quality glass for LCD.

The platinum device is manufactured in various shapes and forms, and the manufactured platinum device is installed in the main part of the glass manufacturing process, and after manufacturing the final glass, manufactures the LCD panel and leads to the product. The platinum material and device manufactured are applied as the core source material for Melter, Refiner, Pipe, Stirrer in the glass manufacturing process line, and the platinum material suitable for each requirement is used.

In particular, with the recent 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 significantly due to the increase in demand for high quality glass for LCD. It is becoming. Platinum material with improved strength is required to manufacture such high-quality glass, and conventionally alloys gold (Au) or platinum material to improve wettability with glass in platinum to increase the strength of platinum. In order to improve the strength of rhodium (Rh), ruthenium (Ru) and the like has been used in order to improve the desorption and heat resistance with glass. These alloying elements are usually employed by platinum to use platinum material. However, the alloying element used as a solid solution is expensive and colored according to the alloying component. Recently, these alloys are very inexpensive and have high temperature strength. It is being replaced by distributed reinforced platinum materials.

Oxide dispersion-enhanced platinum material is an oxide formed and dispersed by alloying an element with superior oxidation power compared to pure platinum. Summarizing the characteristics of oxide-dispersed platinum, there is almost no grain growth even when used for a long time at a high temperature of more than 1200 ℃. Less deformation, recrystallization is hindered by the oxide, and thus have elongated grains, resulting in high high temperature creep strength. In addition, due to the low amount of oxide, zirconium (Zr), samarium (Sm), yttrium (Y), europium (Eu), and hafnium (Pt), platinum-rhodium alloy, platinum-gold alloy, platinum-ruthenium alloy, etc. BACKGROUND ART Platinum materials in which oxides are formed and dispersed using elements such as Hf) have been researched and developed in various ways.

Platinum or platinum alloy materials containing these oxides can be selected from alloying elements depending on the atmosphere and purpose of use. The oxides are dispersed in these platinum alloys, and crystal grains do not grow and deform even when used for a long time at a high temperature of 1200 ° C or higher. It is known to have a small amount, and recrystallization is prevented by oxides, resulting in elongated crystal grains and exhibiting high high temperature creep strength.

Conventionally, the wet method and the dry method are known as a method for producing platinum or platinum alloy powder for producing an oxide dispersion-enhanced platinum or platinum alloy material. In the case of the wet method, platinum or platinum alloys for producing final oxide dispersion-enhanced platinum or platinum alloy materials by adding raw materials such as gold, rhodium, or ruthenium, which are the main alloying elements, and elements for oxide dispersion strengthening to platinum or platinum alloys The powder is prepared. When using the dry method, platinum or platinum alloy ingots are manufactured and made of wire, and then sprayed into water using an arc sprayer, etc. to produce powder, and then pulverized and degassed, and then platinum or platinum alloy material To prepare a platinum or platinum alloy powder to prepare.

When the wet method known in the art is applied, there is an advantage that fine powder can be manufactured. However, complex processes such as dissolution and concentration of platinum, ruthenium, and oxide dispersion-enhanced alloying elements are required. And strong acids such as nitric acid, hydrochloric acid, and aqua regia in the concentration process, there are many difficulties in managing waste liquids and using strong acids, and it is difficult to control the content of alloying elements.

In addition, in the case of the recently known dry method, there is an advantage that it is easier to control the content than the wet method and that the platinum material having a high temperature strength can be manufactured. Processes such as powdering, pulverization and degassing are complicated, resulting in increased costs and reduced purity.

The present invention has been made in order to solve the above-mentioned conventional problems, and relates to a platinum-ruthenium alloy powder manufacturing method for producing an oxide dispersion-enhanced platinum material, and to manufacture and manufacture ingots using a conventional wet method or melting The purpose of the present invention is not to prepare a powder using a complicated process after the wire is manufactured, but to easily prepare a platinum-ruthenium-zirconium alloy powder using plasma after performing an oxidation heat treatment on the manufactured ingot.

In detail, a platinum alloy ingot is prepared by adding a ruthenium and an oxide dispersing alloying element of the target composition to platinum, heat treating the ingot to form an oxide layer, and injecting a certain amount of oxygen after plasma formation to easily add platinum-ruthenium. An object is to produce an alloy powder.

In order to achieve the above object, the present invention is to prepare a platinum alloy ingot by adding the alloying element in an inert atmosphere for the purpose of controlling the composition of the ruthenium and oxide dispersion strengthening alloy element, which is easily oxidized and volatilized when dissolved in the atmosphere, Oxide treatment is carried out as necessary, and oxygen is partially added during plasma formation to prepare scattered platinum alloy powder. Oxide dispersion-enhanced high purity platinum-ruthenium alloy powder having uniform characteristics by reduction treatment and classification using hydrogen heat treatment. It characterized in that the manufacturing.

The present invention aims to easily produce platinum alloy powder using a plasma to the platinum alloy ingot, rather than the conventional wet and dry method in the production of platinum alloy powder used in the oxide dispersion-enhanced platinum material, the existing thermal plasma It is aimed at the production of scattering powder for the production of a platinum alloy powder of uniform purpose composition, rather than the powder production by evaporation after the formation of the molten metal. Through this, in the production of oxide dispersion-enhanced platinum alloy powder, cost reduction is possible, and it is possible to manufacture oxide dispersion-enhanced platinum material having a uniform composition having high strength at high temperature.

1 is a flowchart showing the operation of manufacturing a platinum-ruthenium alloy powder using plasma.

In the production of platinum-ruthenium alloy powder for the production of oxide dispersion-enhanced platinum material, the powder is dissolved in an inert atmosphere in the production of platinum alloy ingot, and the powder is prepared using plasma in the production of platinum alloy powder. It features.

As a method for producing a platinum-ruthenium alloy powder for producing an oxide dispersion-enhanced platinum material, a method of preparing a platinum alloy ingot by adding an alloying element of a desired composition to pure platinum, and oxidizing the platinum alloy ingot To prepare a high-purity platinum alloy powder by the step of setting the oxidized platinum alloy ingot inside the plasma equipment, depressurizing the inside of the plasma equipment, forming a plasma to produce a platinum alloy powder and heat-treating the platinum alloy powder. It is composed of steps.

More specifically, the method for producing a platinum-ruthenium alloy powder for producing an oxide dispersion-enhanced platinum material, comprising: adding a ruthenium and an oxide dispersion-enhanced element to pure platinum to prepare a platinum-ruthenium alloy ingot; Heat-treating the prepared platinum-ruthenium alloy ingot; Pretreating the heat-treated platinum-ruthenium alloy ingot inside the plasma equipment; Pressure-reducing the inside of the plasma equipment, and forming a plasma to prepare scattered platinum-ruthenium alloy powder; Heat-treating and classifying the scattered platinum-ruthenium alloy powder.

Hereinafter, the process steps will be described in detail with reference to embodiments of the present invention and the accompanying drawings.

1 is a flowchart showing the operation of manufacturing a platinum-ruthenium alloy powder using plasma.

As shown in FIG. 1, first, a platinum alloy ingot is prepared by adding an alloying element of the target composition to pure platinum. (S1)

First, in order to facilitate the control of the composition of the alloying elements, it is preferable to prepare a platinum-based platinum alloy by adding platinum and ruthenium alloys or platinum and an element for dispersing strengthening, and adding the remaining alloying elements to form a ternary platinum alloy ingot. . Ruthenium (Ru) is the main alloying element added to the step of preparing a platinum-ruthenium ingot, and the amount of ruthenium alloy added is preferably 0.05wt to 10wt%, which is less than 0.05wt%, the high temperature stability of ruthenium It is difficult to obtain the effect and the effect of suppressing the reaction with the glass, and in the case of 10 wt% or more, the ductility of the platinum material is lowered, and the workability is remarkably lowered, which is not suitable for the glass apparatus. Zirconium (Zr), samarium (Sm), yttrium (Y), europium (Eu), hafnium (Hf), etc. can be selected as an alloy element for oxide dispersion strengthening, and any of these can be selected. There are various types of alloying elements to be added, but considering the use in the glass industry, it is preferable to select an element having a higher oxidation degree than platinum, without inhibiting the corrosion resistance of the platinum material. This is to form an oxide by oxidizing the alloying element first in comparison with platinum in the intermediate atmospheric heat treatment or final atmospheric heat treatment performed to manufacture the type platinum material. The amount of the alloying element for oxide dispersion strengthening is added is characterized in that 0.02 wt% to 1 wt%, which is less than 0.02 wt%, the dispersion strengthening effect of the platinum material can not be obtained, the high temperature strength is lowered, exceeding 1 wt% In this case, 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 preferably selected at the level to improve the workability while maximizing the dispersion strengthening effect. In addition, in the case of ruthenium or an oxide dispersion-enhanced element, it is excellent in oxidizing property compared with platinum, and when dissolved in the air, it is difficult to control the content of the target composition by oxidation and volatilization. desirable.

The prepared platinum alloy ingot is subjected to oxidation treatment to prepare scattering powder. (S2)

In the case of using a plasma, there is an advantage in that the composition does not change even when dissolution and vaporization powder are obtained by plasma. However, in the case of preparing an alloy powder of binary or higher type, the vaporization powder produced by the vaporization temperature between metal elements is different. In this case, there is a high possibility that the composition of the whole powder is not uniform. In order to prevent this problem, the present invention aims to manufacture the scattering powder mainly in an ingot that is uniformly controlled, not vaporized, and to facilitate the preparation of scattering powder, preparing a scattering powder by injecting some oxygen into an oxide or a reaction gas. It was confirmed that it is easy, first of all to perform a heat treatment to facilitate the production of fly ash powder. At this time, the heat treatment temperature is 1 to 5 hours at 800 ~ 1200 ℃, it is advantageous to perform in the air atmosphere, which is difficult to form the oxide layer when the heat treatment conditions are 800 ℃, 1 hour or less, when 1200 ℃, 5 hours or more There is a disadvantage that ruthenium has high volatility, and it is difficult to control the composition of the purpose, and it is preferable to carry out in the air to form an oxide film.

The oxidized platinum-ruthenium alloy ingot is set inside the plasma apparatus. (S3)

It is preferable to clean the inside of the chamber before the plasma treatment to prevent the incorporation of impurities and foreign substances. A platinum alloy ingot is set on the cleaned chamber internal mold and the distance between the plasma torch and the target is adjusted for plasma formation. In order to produce high purity platinum alloy powder, the material of the electrode used for plasma formation is important and it is important to minimize contamination by the plasma electrode. Applicable negative electrode materials may include molybdenum (Mo), tungsten (W), and platinum (Pt), and any one selected from among them may be applicable, and the use of platinum, which is the same material as that of the raw material, may produce high purity powder. Most preferred. Molybdenum (Mo), tungsten (W), copper (Cu), carbon, or platinum (Pt) may be used as the mold material for the anode to which the platinum alloy ingot is set. Is available. Maintaining high purity and minimizing contamination by the mold is important. Platinum, which is the same material, is most preferable, and it is advantageous to select a carbon mold that is easy to remove the contamination even if contamination occurs by the mold.

After depressurizing the inside of the plasma equipment, adjusting the reaction gas and adjusting the working vacuum, electric power is applied to form a plasma to prepare platinum-ruthenium alloy powder in which the ingot is scattered.

In order to form a plasma, a vacuum system was used to reduce the pressure to a level of 10 ⁻¹ torr, and the plasma was formed by applying electric power after adjusting the reaction gas input and working vacuum degree. The main reaction gases used are Ar, H ₂ , Mixed gas such as N ₂ , CH ₄ , Ar + H ₂ , Ar + N ₂ may be used, and any one or more of these may be used, but when using N ₂ , H ₂ or a mixed gas containing them, powder It is most preferable to use Ar because it remains in the platinum powder after manufacture and is trapped in manufacturing the material, so that cracks due to processing may occur. Even if N ₂ and H ₂ are partially contained in the Ar gas to increase the powder production speed, it is preferable to add 1 to 5% or less of the reaction gas content, which is not expected to increase the powder production speed when it is 1% or less. If 5% or more, it is likely to remain in the powder. It is desirable to work at roughly 50 ~ 700 torr. If it is less than 50 torr, the plasma is transferred to the mold, which makes it difficult to transfer heat directly to the material. If it is more than 700 torr, the exhaust capacity is deteriorated. This is because removal of impurities and the like may be difficult. It is desirable to adjust the vacuum degree using other cooling gas attached to the equipment or by using a vacuum control valve. In order to facilitate the preparation of fly ash powder, a small amount of oxygen is added to the main reaction gas. In the previous process, the formation of fly ash powder is easy at the beginning after plasma formation by the formation of oxide by queuing process, but after a certain time, the oxide layer is reduced and there is a limit to the preparation of fly ash powder. It aims to supply around raw materials. The oxygen content is preferably 0.5 to 5% or less than the reaction gas content. When the oxygen content is less than 0.5% to the reaction gas content, the oxygen effect is lowered, making it difficult to prepare scattered powder, and when the oxygen content is 5% or more. There is a possibility of work hazards such as explosion and explosion. Therefore, oxygen content control is necessary. Plasma power is preferably 10 to 100 kw or less. If the power is 10 kw or less, the plasma effect is lowered due to low power, and is performed at 100 kw or less in consideration of the stability of the equipment.

The prepared platinum-ruthenium alloy powder is subjected to heat treatment and classification. (S5)

In general, platinum-ruthenium crucibles of the same material are difficult to apply in terms of cost, and even if they are contaminated, they use a lot of carbon materials that are easy to remove pollutants. When carbon materials are used, they react with carbon due to the properties of platinum group elements. Since vaporization of carbon also occurs, it is possible to produce a high purity platinum-ruthenium alloy powder from which carbon is removed by queuing. In the case of heat treatment, the atmosphere is preferably an atmosphere or an oxygen atmosphere, in order to remove the carbon by forming fine carbon combined with oxygen, gas such as carbon monoxide (CO) or carbon dioxide (CO ₂ ) at a high temperature of 500 ° C. or higher. to be.

In this case, the heat treatment temperature is preferably performed at 600 to 1200 ° C. for 1 hour to 5 hours. If the temperature is 600 ℃ or less and less than 1 hour, the remaining carbon is not likely to be sufficiently removed, resulting in deterioration of processability in the final platinum material. There is a high possibility of coarsening of the oxide dispersion strengthening element.

For the platinum alloy powder from which the carbon component has been removed, a powder of a desired size can be controlled using a standard body. 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.

[Example]

To prepare a powder having a composition of Pt-5.0Ru-0.3Zr (wt%), using a vacuum high frequency induction furnace, 947 gr of platinum having a purity of 3N5 or higher, 50 gr of ruthenium having a purity of 3N5 or higher, 3 gr of zirconium of 3N or higher Ingot was prepared 1,000 gr. The prepared ingot was subjected to a 1 hour queue treatment at 1000 ° C., and a Pt-Ru-Zr powder was prepared using a plasma apparatus. The manufacturing process is as follows. After setting the ingot manufactured in the graphite mold, adjusting the distance from the plasma torch, and reducing the pressure to 10 ^-2 torr using a vacuum pump attached to the plasma equipment, controlling the working vacuum degree to 700torr using a cooling gas, and then Ar Was formed as a reaction gas, and after the plasma was formed, 1% oxygen was added to prepare Pt-Ru-Zr powder, and the process conditions for producing the platinum alloy powder using plasma are shown in Table 1.

Process item
Condition Plasma Formation Step Powder manufacturing step Plasma power (kw) 10 20
Reaction gas Furtherance Ar Ar + O ₂ Gas flow rate
(L / min) 20 19.8 (Ar) /0.2 (H ₂ ) Other gas flow rate (composition)
(L / min) - 320 (N2)

Pt-Ru-Zr powder prepared by plasma was subjected to heat treatment at 900 ° C. × 1 hr in an air atmosphere to obtain Pt-Ru-Zr powder from which carbon was removed.

The prepared powder showed a spherical form, and powder of 1-230 µm level was obtained using a 230 µm standard.

Table 2 shows the results of analysis using EDS and carbon analyzer before and after heat treatment to confirm the presence or absence of carbon for the heat-treated powder.

Item (wt%) Before heat treatment After heat treatment EDS 7 0 Gas Analysis (C) 5 ↑ (Not measurable) 0.01

From the above results, it was confirmed that the carbon is removed by the atmospheric heat treatment, the powder after the heat treatment maintains the shape of the coarse powder before the heat treatment, but in the case of fine powder shows a form that is agglomerated. ICP analysis was carried out to confirm the purity and Zr content of the prepared platinum alloy powder.The ruthenium content was 4.8 wt%, the zirconium content was 0.259 wt%, and the impurity total content was 380 ppm, which was the purity of platinum except ruthenium and zirconium. It was possible to manufacture a platinum-ruthenium alloy powder maintained at a high purity of 3N5 or more.

Claims (11)

In the platinum-ruthenium alloy powder production method for producing an oxide dispersion-enhanced platinum material,
Preparing a platinum-ruthenium alloy ingot by adding ruthenium and an oxide dispersion strengthening element to pure platinum;
Heat-treating the prepared platinum-ruthenium alloy ingot;
Setting the heat-treated platinum-ruthenium alloy ingot inside the plasma equipment;
Preparing a platinum-ruthenium alloy powder in which the ingot is scattered by forming a plasma by depressurizing the inside of the plasma equipment, adjusting the reaction gas and adjusting the working vacuum, and then applying electric power;
Platinum-ruthenium alloy powder manufacturing method comprising the step of heat treatment and classification for the scattered platinum-ruthenium alloy powder. delete The method of claim 1,
A method of producing a platinum-ruthenium alloy powder, characterized in that the amount of ruthenium element added in the step of producing the platinum-ruthenium alloy ingot is 0.05 wt% to 10wt%. The method of claim 1,
Oxide dispersion-enhanced alloying element in the step of producing a platinum-ruthenium alloy ingot, characterized in that any one selected from zirconium (Zr), samarium (Sm), yttrium (Y), europium (Eu), hafnium (Hf). Platinum-ruthenium alloy powder manufacturing method to use. The method according to claim 1 or 4,
Platinum-ruthenium alloy powder manufacturing method, characterized in that the amount of the oxide dispersion-enhanced alloying element added to the step of producing a platinum-ruthenium alloy ingot is 0.02 wt% to 1 wt%. The method of claim 1,
Method for producing a platinum-ruthenium alloy powder, characterized in that heat treatment for 1 to 5 hours at a temperature of 800 ℃ to 1200 ℃ in the air for the prepared platinum-ruthenium alloy ingot. The method of claim 1,
The material of the mold used in the plasma equipment is molybdenum (Mo), tungsten (W), copper (Cu), carbon (Carbon) or platinum (Pt), characterized in that any one of the platinum-ruthenium alloy powder manufacturing method. The method of claim 1,
The material of the cathode used in the plasma equipment is molybdenum (Mo), tungsten (W) or platinum (Pt) any one selected from platinum-ruthenium alloy powder manufacturing method. The method of claim 1,
The reaction gas used for plasma formation is Ar, H ₂ , N ₂ , CH ₄ , Ar + H ₂ , Ar + N _{2 The} platinum-ruthenium alloy powder manufacturing method, characterized in that at least one selected from. The method of claim 1,
Oxygen is added to the reaction gas after the plasma formation, the content of oxygen is 0.5 to 5% compared to the content of the reaction gas platinum-ruthenium alloy powder manufacturing method. The method of claim 1,
Platinum-ruthenium alloy powder prepared by plasma, characterized in that the heat treatment for 1 to 5 hours at an air atmosphere or oxygen atmosphere at a temperature of 600 ℃ to 1200 ℃.

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