TW201510244A - Method for preparing platinum-rhodium-oxide based alloy - Google Patents

Abstract

The present disclosure provides a method for preparing a high-density dispersion strengthening type platinum-rhodium-oxide based alloy.

Description

Method for preparing platinum-rhodium oxide alloy material

The present invention relates to a process for preparing a high-density oxide dispersion-strengthened platinum-rhodium oxide-based alloy.

Dispersion strengthening is a method of strengthening a metal material by dispersing dispersed particles composed of carbides, nitrides, and oxides of other metals in a parent phase metal and using dispersion. The action of the particles increases the mechanical properties of the parent metal.

Regarding the parent phase metal, platinum is usually used, and although it is expensive, platinum has a high melting point, platinum is easily handled at room temperature and high temperature, and platinum has excellent chemical resistance, corrosion resistance, and volatility.

In the related art, in order to increase the strength of platinum, a solid-solution strengthened platinum material is generally used, by alloying platinum with an element such as gold (Au) and rhodium (Rh). obtain. However, recently, due to the increase in the price of alloying elements (for example, gold, rhodium, etc.) using strengthening elements, in order to replace alloy materials (for example, platinum-gold and platinum-ruthenium), it has been developed to use an element having excellent oxidizing power. To form oxidation And dispersed in the platinum alloy material.

For example, oxide particles of a metal (for example, zirconium) in a platinum alloy are dispersed in platinum as a parent phase metal. It is known that even when a platinum alloy is used for a long time at a high temperature of 1,200 ° C or higher, the platinum alloy exhibits slight grain growth and small deformation, and the platinum alloy has a strengthened crystal when the recrystallization is inhibited by the metal oxide. The granules have a large high temperature creep strength and also lower their price.

The dispersion-strengthened alloy is easily deformed by high temperature and high pressure, and the dispersion-type alloy has excellent high-temperature latent characteristics, and therefore, the alloy can be used as a material for manufacturing high-quality LCD glass and devices.

In the related art, a method for producing an oxide dispersion-strengthened alloy is as follows: an alloy ingot having a target composition is prepared, and then a plasma is used to prepare a platinum alloy powder. An advantage of this preparation method is that the content of the oxide element can be easily controlled, but the disadvantage is that the yield is slightly reduced due to the scattered powder, and since the preparation time is increased, the price is also required to be high.

[Patent Document]

Korean Patent No. 1,288,592.

The present invention is directed to providing a high-density oxide dispersion-strengthened platinum-rhodium oxide alloy having excellent high temperature latent strength. method.

An exemplary embodiment of the present invention provides a method for preparing a platinum-rhenium oxide-based alloy, comprising: forming an alloy ingot comprising (i) platinum, (ii) antimony, and (iii) one or more metal systems Freely selected: a group consisting of zirconium, hafnium, niobium and tantalum; and an alloy thin plate formed by melt-spinning the alloy ingot; internally oxidizing the alloy sheet, which is tied to the air Performing heat treatment of the alloy sheet in an atmosphere; laminating or grinding the inner oxide alloy sheet, and subjecting the inner oxide alloy sheet to high temperature press forming; thermally processing the high temperature press formed alloy sheet; cold working the hot worked An alloy sheet; and heat treating the cold worked alloy sheet.

The alloy ingot may comprise from 5 to 20 weight percent bismuth; from 0.02 to 0.8 weight percent oxide metal; and the balance platinum, based on 100 weight percent of the alloy ingot.

The formed alloy sheet may include: forming a melt formed by melting the alloy ingot under a high vacuum of 10 ^-4 Torr to 10 ^-3 Torr; and spraying the melt at 500 rpm to 3,000 rpm The surface of the copper wheel is pressurized with an inert gas at 0.1 to 1.0 MPa.

This internal oxidation can be carried out by performing a heat treatment at a temperature of from 800 ° C to 1,000 ° C for 1 to 5 hours.

The high temperature press molding may be a hot pressing or a hot isostatic pressing, and may be carried out at a temperature of 1,200 ° C to 1,400 ° C for 1 to 5 hours under a pressure of 0 MPa to 50 MPa.

Preferably, the temperature is carried out at a temperature of from 1,000 ° C to 1,400 ° C. Thermal processing.

Preferably, the cold working is carried out at a reduction ratio of 40% to 90%.

This heat treatment can be carried out at a temperature of 1,200 ° C to 1,400 ° C for 1 to 5 hours.

According to the method for producing a platinum-ruthenium oxide-based alloy of the present invention, the number of processes and the preparation time can be reduced by using a melt-spinning method to prepare the metal thin plate, followed by oxidizing the metal thin plate in a heat treatment only in the air. To increase the competitiveness of the price.

The density of the platinum-rhenium oxide-based alloy can be increased, and the high-temperature creep strength can be increased.

The foregoing summary is for illustrative purposes only and is not intended to be limiting. Further aspects, specific embodiments, and features of the invention will become apparent from the Detailed Description of the Drawing.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart showing the steps of a method for preparing a platinum-rhenium oxide alloy in the prior art.

Figure 2 is a flow chart showing the steps of a method for preparing a platinum-rhenium oxide-based alloy according to the present invention.

3 is a transmission electron microscope (TEM) photograph of the alloy sheet prepared in Example 1.

4 shows the preparation of platinum in each of the processes of Example 1 and Comparative Example 1. - Photograph of bismuth oxide alloy.

Fig. 5 is a EBSD analysis photograph of the platinum-rhenium oxide-based alloy prepared in Example 1.

Fig. 6 is a EBSD analysis photograph of the platinum-rhenium oxide-based alloy prepared in Comparative Example 1.

In the following embodiments, reference to the additional drawings is part of the present invention. It is not intended to be limited to the illustrative embodiments described in the embodiments, the drawings, and the claims. Other embodiments and other changes may be made without departing from the spirit and scope of the invention.

Hereinafter, the present invention will be described with reference to Fig. 2 .

The present invention provides a method for preparing a platinum-rhenium oxide-based alloy comprising: forming an alloy ingot comprising (i) platinum, (ii) antimony, and (iii) one or more oxides selected from the group consisting of zirconium a group consisting of ruthenium, osmium, and iridium; and forming an alloy sheet formed by melt-spinning the alloy ingot; internally oxidizing the alloy sheet by heat-treating the alloy sheet under an air atmosphere Performing; laminating or grinding the inner oxidized alloy sheet, and subjecting the inner oxidized alloy sheet to high temperature press forming; thermally processing the high temperature press formed alloy sheet; cold working the hot worked alloy sheet; and heat treating the cold worked alloy sheet.

Hereinafter, each step of the preparation method will be described.

First, forming a metal containing (i) platinum (Pt), (ii) ruthenium (Rh), and (iii) one or more selected from the group consisting of zirconium (Zr), strontium (Sm), ytterbium (Y), and yttrium (Hf) Group A group is formed (step S100).

In one embodiment, in step S100, by mixing and melting platinum, rhodium, and one or more metals selected from the group consisting of: zirconium, hafnium, tantalum, and niobium; melting the metal; and then injecting the melt The object has a model having a predetermined shape to form the alloy ingot.

The content of platinum is not particularly limited, but may be a maintained amount to obtain a total weight of the alloy ingot of 100% by weight.

Antimony is an element that is added for solid solution strengthening.

The content of cerium is not particularly limited, but when the content is 5 to 20% by weight, an excellent solid-solution strengthening effect can be obtained. When the content of cerium is less than 5% by weight, the solid-solution strengthening effect cannot be obtained due to cerium, and when the content exceeds 20% by weight, the strength is increased by solid solution strengthening due to cerium, but during post-treatment Cracking occurs so that the high temperature strength increased in the platinum-rhenium oxide-based alloy causes damage.

The alloy ingot comprises more than one metal selected from the group consisting of zirconium, hafnium, tantalum and niobium.

The metal as described above does not reduce corrosion resistance, can be easily converted into an oxide due to an oxidation degree higher than platinum and rhodium, and can be increased in dispersion due to stability at a high temperature of 1,400 ° C or higher. effect.

The content of the metal is not particularly limited, but when the content is 0.02 to 0.8% by weight, an excellent dispersion strengthening effect of the alloy can be obtained. When the content of the alloying element of the oxide is less than 0.02% by weight, the dispersion strengthening effect of the platinum-rhenium oxide-based alloy cannot be obtained. When the content is super When the amount exceeds 0.8% by weight, the latent strength of the alloy is increased, but since the dispersion strengthening effect is increased by maintaining the dispersed particles, the processability may be deteriorated.

Therefore, preferably, the content of cerium and one or more metals is selected from a range capable of performing processability while maximizing solid solution strengthening and dispersion strengthening effects.

In step S100, since the alloying element of the oxide has better oxidation property than platinum or rhodium, when the alloying element of the oxide is melted in the air, it is difficult to control the oxide due to the relationship between oxidation and evaporation. The content of the alloying element. Therefore, it is preferred to melt the alloying element of the oxide under vacuum or in an inert gas atmosphere.

The melting temperature is not particularly limited, but it is preferably melted at 1,200 ° C to 1,400 ° C.

Thereafter, the alloy ingot obtained in the step S100 is spin-quenched to form an alloy sheet (step S200).

Since the alloy sheet having a small thickness is formed through the step S200, even in the following step S300, the heat treatment is performed under air, and the oxidation can be sufficiently performed in a short time.

The alloy ingot is embedded in a nozzle provided in a melt quenching apparatus, and the alloy ingot is completely melted under a high vacuum of 10 ^-4 Torr to 10 ^-3 Torr to form a melt. Next, an inert gas is pressurized at 0.1 MPa to 1.0 MPa and sprayed onto the melt, and the sprayed melt begins to contact the surface of a rotating copper wheel that is vertically disposed under the nozzle and away from the nozzle. And rapidly spraying the sprayed melt, thereby forming an alloy sheet.

The inert gas is not particularly limited, but is preferably argon.

The rotation speed of the copper wheel is not particularly limited, but when the speed is 500 rpm to 3,000 rpm, the melt contacts the surface of the copper wheel and is rapidly cooled, and the thickness of the formed alloy can be adjusted. However, since the metal thin plate is thin, in the following step S300, oxidation can be sufficiently obtained in a short time. Therefore, the thickness of the sheet can be adjusted. The thickness is preferably from about 50 μm to about 200 μm. The thickness of the metal sheet can be controlled by adjusting the gap of the melt, wherein the melt contacts the copper wheel.

Quartz, graphite, etc. are materials having a higher melting point than platinum, and since platinum has a high melting point, it can be used as a nozzle.

Thereafter, the alloy sheet obtained in step S200 is subjected to heat treatment under air and subjected to internal oxidation (step S300).

The metal oxide is uniformly formed in a short time by heat treatment under air, and the metal is selected from the group consisting of zirconium, hafnium, tantalum and niobium.

The temperature and time of the heat treatment are not particularly limited, but the temperature is preferably in the range of 800 ° C to 1,200 ° C, and the time is preferably from 1 to 12 hours. When the heat treatment temperature is less than 800 ° C, or the heat treatment time is less than 1 hour, the oxide of the alloying element may not be sufficiently obtained. When the temperature exceeds 1,200 ° C or the time exceeds 12 hours, the alloying element is coarsened, so that the dispersion effect can be broken.

Thereafter, the inner oxide alloy sheet obtained in step S300 is laminated or ground, and subjected to high temperature press molding (step S400).

Relative density of one of the oxidized alloy sheets in step S400 Can be adjusted to more than 80%.

The high temperature press molding includes, for example, hot press (HP) or hot isostatic press (HIP), but the present invention is not limited thereto.

The temperature and time of the high temperature press molding are not particularly limited. However, it is preferred to carry out the preparation for 1 to 5 hours at a temperature ranging from 1,200 ° C to 1,400 ° C under a pressure of 10 MPa to 50 MPa. When the temperature of the high-temperature press molding is less than 1,200 ° C, when the time is less than 1 hour, or the pressure is less than 10 MPa, a high-density sintered body cannot be obtained. When the temperature exceeds 1,400 ° C or the time exceeds 5 hours, the dispersion strengthening effect is likely to be broken due to the coarsening of the oxide. Pressures in excess of 50 MPa can pose a hazard to the models and equipment used.

Thereafter, the alloy sheet obtained in step S400 is subjected to hot working (step S500).

The hot working in step S500 is for obtaining a high-density alloy, and the relative density obtained in step S400 via the hot working can be adjusted to 98% or more. The thermal processing includes, for example, hot rolls, hot forging, and the like, but is not limited thereto.

When the relative density is less than 98%, even if the relative density is changed to 99% or more due to the subsequent cold working, the pores maintained during the hot working are not removed. Therefore, it is highly likely that bubbles are generated on the surface of the alloy by heat treatment or internal bonding or the like.

The temperature of the hot working is not particularly limited, and is preferably in the range of 1,000 ° C to 1,400 ° C. When the temperature is less than 1,000 ° C, in the heat Cracking is likely to occur during processing, and it is difficult to ensure the high density of the alloy. When the temperature exceeds 1,400 ° C, the alloying element of the oxide is coarsened, so that the dispersion strengthening effect of the alloy can be deteriorated.

Meanwhile, the alloy sheet obtained in the step S500 may be heat treated before the step S600 described below. Thereby, cracking can be avoided during cold working.

After the hot working, cold working is performed to control the thickness (step S600).

Non-limiting examples of the cold working include: cold-rolling, cold-forging, etc., preferably a chill roll.

The deformation rate of the cold roll is not particularly limited, but is preferably 40% to 90%. When the deformation rate is less than 40%, even after the subsequent heat treatment, the work stress is so low that recrystallization cannot be produced. When the deformation rate exceeds 90%, it is highly likely to decompose the alloy due to high working stress.

After the cold working, heat treatment is performed to recrystallize the fine structure (step S700).

The temperature and time conditions of the heat treatment are not particularly limited, but it is preferably heat-treated at a temperature ranging from 1,200 ° C to 1,400 ° C for 1 to 5 hours. When the temperature is less than 1,200 ° C or the time is less than 1 hour, recrystallization of the fine structure can be inhibited. When the temperature exceeds 1,400 ° C or the time exceeds 5 hours, the hardness can be broken due to crystal grains and oxides.

Hereinafter, the present invention will be specifically described by way of examples, but the following examples and experimental examples illustrate only one form of the invention. this invention The scope of the invention is not limited to the following examples and experimental examples.

Example 1

By embedding 99.7 weight percent of PtRh10 and 0.3 weight percent of Zr into a vacuum high frequency induction melting furnace, wherein the PtRh10 has a purity of 3N5, and the Zr has a purity of 3N; The mixture is then cured to obtain an alloy ingot. Thereafter, by embedding the alloy ingot into a melt-spinning equipment, the argon gas was pressurized at 0.3 MPa to 0.5 MPa, and the melt was sprayed on the surface of the copper wheel to obtain an alloy sheet. In this case, the rotational speed of the copper wheel is set to 500 rpm to 3,000 rpm. The inner oxidized alloy sheet is prepared by an alloy sheet obtained by heat treatment at 800 ° C to 1,000 ° C under air for 1 to 5 hours.

Thereafter, the inner oxide alloy sheet was laminated or ground, and pressure-sintered at 1,400 ° C for 2 hours under a pressure of 20 MPa. Next, the measured alloy sheets had a relative density of 86.5%. Thereafter, hot forging was performed at a temperature of 1,200 °C. Next, the measured alloy sheets had a relative density of 98.0%. Thereafter, the chill roll was carried out at a deformation rate of 40%. Next, the measured relative density of the alloy sheet was 99.9%. Next, the platinum-rhodium-oxide-based alloy was heat-treated at 1,200 ° C for 1 hour in the air.

Figure 3 illustrates the penetration of the internally oxidized alloy sheet as a transmission electron microscope (TEM) photograph. It is known that the Zr metal oxide having a size of about 200 nm is uniformly dispersed and formed along a grain boundary.

Comparative example 1

By embedding 99.7 weight percent PtRh10 and 0.3 weight percent Zr into a vacuum high frequency induction melting furnace, wherein the PtRh10 has a purity of 3N5, and the Zr has a purity of 3N; melting the mixture; then solidifying the melt to An alloy ingot is obtained. Thereafter, a vacuum pump attached to the plasma device is used to lower the pressure to 10 ^-3 Torr, and then, plasma is formed by using argon gas as a reaction gas; the alloy ingot is melted; and plasma power is increased to prepare a powder. By introducing the obtained powder into a square molded body carbon model; and heat-treating the powder at 1,300 ° C for 2 hours under an argon atmosphere to prepare a molded body; and heat-treating at 1400 ° C for 2 hours under air, To prepare an internal oxidation molded body.

Thereafter, the thus-oxidized molded body was pressure-sintered at 1,400 ° C for 2 hours under a pressure of 20 MPa. After the pressure sintering, the relative density of the molded body measured was 93.4%. Thereafter, hot forging was performed at a temperature of 1,200 °C. After hot forging, the relative density of the molded body measured was 97.6%. Thereafter, the chill roll was carried out at a deformation rate of 40%. Next, the relative density of the molded body measured was 99.2%. Next, a platinum-rhenium-oxide-based alloy was prepared by heat-treating at a temperature of 1,200 ° C for 1 hour under air.

Experimental example: Confirmation of alloying element content

The content of the element and the alloy sheet of the ingot in Example 1 was confirmed by an ICP analysis method. The results are shown in Tables 1 and 2 below, respectively.

As is apparent from Table 1, in the case of the platinum-rhodium-oxide-based ingot, the zirconium content as an oxide alloying element is represented by 0.2156% by weight, which is similar to the target composition. Even in the platinum-iridium-oxide-based alloy sheet shown in Table 2, the content of zirconium was expressed as 0.2444% by weight.

Experimental Example 2: Measurement of relative density

After the pressure sintering, the hot forging, and the chill roll, the relative densities of the platinum-rhodium-oxide-based alloys in Example 1 and Comparative Example 1 were measured, respectively. The result is shown in Fig. 4.

As illustrated in Figure 4, the platinum-bismuth-oxide alloy is pressure-burned. In the case of the junction, it was found that the alloy of Comparative Example 1 had a higher relative density than the alloy of Example 1, but in the case where the alloy was subjected to the hot forging and cold rolling steps, the alloy of Example 1 was found to have higher The relative density of the alloy of Comparative Example 1. A cold roll was carried out, and the relative density of the alloy of Example 1 was measured using the Archimedes method, and the density was 99.9%, which was a relatively high value.

Experimental Example 3: EBSD Analysis

The cross section of the platinum-rhodium-oxide-based alloy prepared in Example 1 and Comparative Example 1 was subjected to EBSD analysis, and the results are shown in Figs. 5 and 6, respectively.

As illustrated in Fig. 5, it can be understood that when the structure of the alloy can be observed after the chill roll, the crystal grains are arranged along the roll direction. It can be seen that even after heat treatment at a high temperature of 1,500 ° C, the growth of crystal grains is inhibited by the distribution of fine ZrO ₂ oxide, and equiaxed grains are maintained. However, under the conditions of the alloy of Comparative Example 1, it was found that the crystal grains were coarsened by recrystallization of the structure after the heat treatment was performed at a high temperature.

In view of the foregoing, it will be appreciated that the various embodiments of the invention are described herein, Modification. Therefore, the various embodiments of the invention are not intended to be limited to the scope of the invention.

Claims (9)

A method for preparing a platinum-rhodium oxide-based alloy, comprising: forming an alloy ingot comprising (i) platinum, (ii) antimony, and (iii) one or more metals selected from the group consisting of zirconium, hafnium, tantalum, and niobium a group formed; and forming an alloy sheet formed by melt-spinning the alloy ingot; internally oxidizing the alloy sheet by heat-treating the alloy sheet under an air atmosphere; laminating or grinding The inner oxide alloy sheet is subjected to high temperature press forming of the inner oxide alloy sheet; the high temperature press formed alloy sheet is thermally processed; the hot worked alloy sheet is cold worked; and the cold worked alloy sheet is heat treated. The method of claim 1, wherein the alloy ingot comprises: 5 to 20% by weight of bismuth; 0.02 to 0.8% by weight or more of metal based on 100% by weight of the alloy ingot; platinum. The method of claim 1, wherein the forming of the alloy sheet comprises: forming a melt which is formed by melting the alloy ingot under a high vacuum of 10 ^-4 Torr to 10 ^-3 Torr. And spraying the molten material onto the surface of the copper wheel rotated at 500 rpm to 3,000 rpm by pressurizing an inert gas at 0.1 to 1.0 MPa. The method of claim 1, wherein the internal oxidation is carried out at 800 ° C to 1,000 ° C for 1 to 5 hours. The method of claim 1, wherein the high temperature press molding is a hot pressing or a hot isostatic pressing. The method according to claim 1, wherein the high-temperature press molding is performed at a temperature of 1,200 ° C to 1,400 ° C under a pressure of 10 MPa to 50 MPa for 1 to 5 hours at a high temperature. The method of claim 1, wherein the hot working is performed at a temperature of from 1,000 ° C to 1,400 ° C. The method of claim 1, wherein the cold working is performed at a reduction rate of 40% to 90%. The method of claim 1, wherein the heat treatment is carried out at a temperature of 1,200 ° C to 1,400 ° C for 1 to 5 hours.