JP2015517030A - Manufacturing method of oxide dispersion strengthened platinum-gold alloy - Google Patents

Abstract

The present invention relates to the manufacture of an oxide dispersion strengthened platinum-gold alloy material used in a melting apparatus at the time of glass production, and a platinum alloy powder containing platinum, gold and an alloy element for oxide and final oxidation using plasma. To produce an oxide dispersion strengthened platinum-gold alloy material with finely dispersed materials. The present invention has been devised to overcome the disadvantages of vitreous coloring and severe price fluctuations of alloying elements when using a platinum-rhodium alloy used in the past. For this purpose, gold is vaporized first due to the difference in the melting point of platinum and gold in the plasma process after the platinum-gold alloy ingot is manufactured by adding the gold and oxide alloy elements, which are the target composition, to platinum. In order to suppress oxidative heat treatment, after surface oxidation, plasma powder is used to produce alloy powders of platinum, gold and alloying elements for oxides, and the produced powders are introduced and subjected to pressureless firing. Oxide dispersion strengthened platinum in which fine oxides are dispersed by manufacturing compacts by sintering, improving density through high temperature oxidation heat treatment and high temperature pressure sintering, followed by hot working and cold working final heat treatment -Manufacture gold materials. [Selection] Figure 1

Description

  The present invention relates to a technique for producing an alloy powder containing platinum, gold, and an oxide element using plasma, and producing an oxide dispersion strengthened platinum-gold material using the same. Is often used in places where high-temperature strength is required, such as platinum-containing equipment used in glass-related industries (melting equipment, crucibles, bushings, stirrers, etc.) In particular, the present invention relates to the production of a platinum material obtained by alloying gold, which plays a role of improving the contact angle between a platinum crucible used in glass production and a glass melt.

  Platinum, which has a high melting point and has high chemical resistance and corrosion resistance at high temperatures, can be easily processed at room temperature and high temperature and does not volatilize easily. It is used in many industries, such as ornaments, dental equipment, automotive catalysts, and the glass industry.

  Particularly recently, with the steady growth of the LCD industry, the use of platinum materials with improved strength is increasing for the manufacture of high quality glass manufacturing materials and devices for LCDs.

  Conventionally, in order to improve the strength of pure platinum, platinum material that has been strengthened by solid solution strengthening by alloying gold (Au), rhodium (Rh), or a ternary element to platinum has been mainly used. However, recently, the price fluctuations of alloying elements used for strengthening elements are large, and there are disadvantages that bubbles are generated when the glass melts, and glass objects are colored by alloying components. Instead of such alloys, platinum alloy materials that are dispersion strengthened with oxides having superior high temperature creep properties have been substituted.

  In order to solve the problems of platinum and platinum-rhodium materials that are solid solution strengthened as described above, platinum and platinum materials in which oxides are formed and dispersed using elements having higher oxidizing power than rhodium are used. Although platinum materials containing these oxides have been developed, even if they are used at a high temperature of 1200 ° C. or higher for a long time, there is almost no growth of crystal grains, deformation is small, and recrystallization is hindered by oxides. It is known to have stretched grains and to achieve higher high temperature creep strength.

  Also, by adding gold, the contact angle between the glass melt to be manufactured and the melting device in which the platinum material is used is improved, the separation between the crucible and the melt is easy, and the cost is reduced and used. Lifespan can be improved.

  As a method for producing an oxide dispersion strengthened platinum-gold material, there is a dry method that is easy to control the oxide content and is excellent in high temperature strength. Compared to conventional wet methods, this dry method has the advantage that the oxide element content can be easily controlled and has excellent high-temperature strength, but the process is complicated and the purity of the material is reduced. Disadvantages and increased costs due to increased overall manufacturing time.

  The present invention has an improved contact angle with a glass melt as compared with a platinum-rhodium alloy that has been used in the past, and is easily separated from the melt after the manufacturing process. In the production of materials, a platinum-gold ingot is subjected to a surface oxidation process in which an oxidation heat treatment is performed, and plasma is used to produce usable high-purity platinum-gold powder, and oxidation is performed using this. The object is to provide a material-dispersion strengthened platinum-gold material.

  In order to solve this problem, gold and oxide alloying elements of the desired composition are added to platinum, and an alloy ingot of platinum-gold-oxide alloying elements is manufactured by vacuum melting to suppress gold vaporization. In order to do this, after surface oxidation, platinum alloy powder is produced using plasma, and then heat treatment is performed in the atmosphere to produce a molded body, oxidation heat treatment, high-temperature pressure heat treatment, hot working, cold working and final recrystallization. Heat treatment is performed to produce an oxide dispersion strengthened platinum-gold material.

  In the present invention, a platinum alloy ingot is manufactured by adding gold and an oxide alloying element having a target composition to platinum under a vacuum atmosphere or an inert atmosphere. Producing platinum alloy powder by using, producing platinum alloy compact by pressureless vacuum or atmospheric heat treatment, oxidizing alloy elements by high-temperature atmospheric heat treatment, and producing high-density sintered compact by high-temperature pressure molding The present invention is characterized in that a hot working, a cold working and a recrystallization heat treatment are performed to produce an oxide dispersion strengthened platinum-gold material.

  Maintains high high-temperature creep strength by dispersing oxides compared to previously known platinum-rhodium alloys when manufacturing powders of oxide dispersion strengthened platinum-gold alloy materials that improve contact angle This improves the contact angle between the platinum alloy material used in the glass melting device and the glass melt, facilitates the separation of the platinum material and the glass melt, and improves the life of the melting device. The

  Therefore, the core composition of the present invention is the platinum-gold which can be finally used by using plasma instead of the spray method used in the existing dry method in the production of oxide dispersion strengthened platinum-gold powder. It is to produce alloy powder.

1 is a procedural diagram showing a method for producing an oxide dispersion strengthened platinum-gold alloy according to the present invention. It is a figure which shows the microstructure of the cross-sectional part after the heat processing of the oxide dispersion strengthened platinum-gold raw material manufactured by this invention. It is a figure which shows the comparison result of the contact angle of the melt | dissolution of the oxide dispersion strengthening type platinum-gold raw material manufactured by this invention, and the oxide dispersion strengthening type platinum-rhodium alloy used conventionally.

  According to the present invention, in a production method for producing an oxide dispersion strengthened platinum-gold alloy for improving the wettability between a glass melt and a platinum-based material during the production of glass, a gold having a target composition is applied to platinum. And the alloying element for oxide to produce a platinum-gold-oxide alloy ingot, and after the surface of the platinum-gold-oxide alloy ingot is oxidized before the plasma process A second stage in which powder is formed using plasma, a third stage in which the manufactured powder is subjected to an oxidation heat treatment to produce a molded body having a fixed shape in which the oxide element is oxidized, and an oxidation treatment. The final oxide dispersion-strengthened platinum-gold by the fourth stage to ensure high density by performing high-temperature pressure molding on the molded body and post-processing such as hot working, cold working and recrystallization heat treatment Consisting of the fifth stage of producing the material Oxide-dispersion strengthened platinum and symptoms - method of manufacturing a gold alloy is provided.

  In the production of oxide dispersion-strengthened platinum-gold materials, in the plasma process, after the platinum-gold-oxide elemental alloy ingot is produced under a vacuum or an inert atmosphere, and before the powder is produced. In order to suppress the vaporization of gold faster due to the difference in melting point between platinum and gold, after the surface oxidation treatment, plasma is used, the crushing and degassing steps are omitted, and the final molding and sintering are performed. It is characterized by producing possible powders.

  This reduces manufacturing time, minimizes contamination and saves costs compared to existing powder manufacturing processes using dry methods, and enables the production of oxide dispersion strengthened platinum gold materials. become.

  The manufacturing method for manufacturing the oxide dispersion strengthened platinum-gold material includes the step of manufacturing a platinum-gold-oxide alloy ingot by adding gold and an alloying alloy element for oxide to platinum (S10), The platinum-gold-oxide alloy ingot is subjected to surface oxidation in order to suppress the vaporization of gold due to the difference in melting point between platinum and gold during powder production, and then a powder is formed using plasma. Step (S20): Oxidation heat treatment is performed on the produced powder to produce a molded body having a fixed shape in which the oxide element is oxidized (S30). High-temperature pressure molding is performed on the oxidized body. It is composed of a step of improving the density by performing (S40) and a step of manufacturing a final oxide dispersion strengthened platinum-gold material by post-processing such as hot processing, cold processing and final heat treatment (S50). ).

  Hereinafter, the process steps will be described in detail.

  First, an ingot of a platinum-gold-oxide alloy is manufactured by adding gold and a reinforcing element for oxide to the high-purity platinum (S10).

  Among the alloy elements to be added, the gold content is 1 to 5 wt%. However, when the content is 1 wt% or less, not only cannot the solid solution strengthening effect with the addition of gold be obtained, but also contact with the glass melt. If the angle is not improved and is 5 wt% or more, there is a disadvantage that the improvement of the contact angle by gold is rather lowered.

  Zirconium (Zr), samarium (Sm), yttrium (Y), hafnium (Hf), etc. are preferably added as metal elements added to the oxide alloy elements. Various types can be selected, but taking into account its use in the glass industry, it does not impair corrosion resistance, has a higher degree of oxidation than platinum and gold, and is stable even at high temperatures of 1400 ° C or higher. It is desirable to select an oxide element.

  The amount of the alloying element for oxide added is 0.02 wt% to 0.8 wt%. However, if the amount is less than 0.02 wt%, there is almost no dispersion strengthening effect. Although the strength is improved, there is a disadvantage that the dispersion strengthening effect by the residual dispersed particles is increased and the workability is lowered.

  Therefore, it is desirable to select the amount of the alloy element for gold and oxide within a range in which workability is possible while maximizing the effect of solid solution strengthening and dispersion strengthening.

  In particular, the above alloying elements for oxides are more oxidizable than platinum and gold, and when dissolved in the atmosphere, it is difficult to control the content of the elements for oxides by oxidation and vaporization. It is desirable to perform the dissolution in the original.

  In order to suppress the vaporization of gold due to the difference in melting point between platinum and gold during the production of the powder in the produced platinum-gold-oxide alloy ingot, the powder is produced using plasma after the surface oxidation ( S20).

  After the ingot is manufactured, when the powder is manufactured using plasma, the gold is vaporized by performing surface oxidation treatment to prevent the gold from being vaporized first due to the difference between the melting points of platinum and gold. Suppress.

  After that, in the method of producing powder using plasma, the ingot material is placed on the mold inside the plasma equipment, and after forming the plasma by reducing the pressure, the plasma power is increased to melt and vaporize the ingot. To obtain a powder.

  As a material that can be used for the mold in which the ingot is disposed, it is necessary that the material to be used has a high melting point. Therefore, molybdenum (Mo), tungsten (W), graphite, platinum (Pt ) Etc. can be used.

  It is desirable that the finally obtained powder minimizes mold contamination and maintains high purity. Among the crucible materials described above, graphite and platinum molds of the same material that can be easily removed by atmospheric heat treatment or oxidation heat treatment. It is most desirable to use

  The electrode (cathode) material for plasma formation is also important. As the usable material, molybdenum (Mo), tungsten (W), platinum (Pt) can be used, and platinum of the same material should be used. desirable.

  The produced platinum-gold-oxide alloy powder is subjected to an oxidation heat treatment to produce a molded body in which the oxide element is oxidized (S30).

  The size of the powder produced using plasma varies widely from several tens of nanometers to several tens of micrometers. To achieve uniform physical properties of the final oxide dispersion strengthened platinum-gold alloy material It is desirable to classify the produced powder and use a powder of a certain size.

  The shape inside the mold for manufacturing the molded body is manufactured in a desired shape of circular or square, and the powder manufactured using plasma is put into the mold and then subjected to oxidation heat treatment.

  The heat treatment carried out at this time is aimed at producing a molded body having a fixed shape, and since it is important to form an oxide for an oxide element, it is oxidized using a mold having a fixed shape in the atmosphere. However, if it is difficult to produce a mold material that can be applied to a high oxidation heat treatment temperature, the molded body is first produced in a vacuum or in an inert atmosphere using a carbon mold. Thus, by separating the mold and the molded body and subjecting only the molded body to air or an oxidation heat treatment, an oxidized molded body can be manufactured.

  At this time, it is preferable that the heat treatment is performed at a temperature of 1000 ° C. to 1400 ° C. and for 2 to 5 hours. However, when the temperature is 1000 ° C. or less or 2 hours or less, the sintering is sufficiently performed. Since the molded body is easily damaged, the post-processing is difficult to proceed and the oxide alloy element may not be sufficiently oxidized. When the temperature is 1400 ° C. for 5 hours or more, the alloy element becomes coarse. This is because the dispersion strengthening effect is reduced.

  In the production of a molded body, it is necessary to sufficiently oxidize an alloy element that is easier to oxidize than platinum. For this reason, a low-density platinum alloy molded body that is advantageous for oxidation must be produced. Therefore, it is desirable to perform the heat treatment under no pressure in order to produce a uniform oxide dispersion strengthened platinum-gold material.

  Desirably, the platinum alloy molded body is heat-treated at a temperature of 1000 ° C. to 1400 ° C. for 2 to 5 hours in a vacuum or an inert atmosphere, and subsequently 2 to 5 at a temperature of 1000 ° C. to 1400 ° C. in the atmosphere. Heat treatment is performed for a period of time.

  In order to improve the density of the oxidized platinum alloy compact, high-temperature pressure molding is performed to produce a sintered compact (S40).

  The oxidized molded body can be densified by hot working such as hot forging or hot rolling, but when it is manufactured in a non-pressurized state during oxidation heat treatment, the density is low, If hot working is performed immediately thereafter, the molded body is likely to be damaged. Therefore, it is desirable to perform high-temperature pressure molding before hot working so as to have a relative density of 80% or more.

  In the high-temperature pressure molding process applicable at this time, hot pressing (HP) or hot isostatic pressing (HIP) is possible, and in the temperature range of 1200 ° C. to 1400 ° C. for 1 to 5 hours, It is desirable to manufacture at a pressure of 50 MPa.

  When the temperature is 1200 ° C. or lower, the sintering time is insufficient, or the pressure is low, a high-density sintered body cannot be obtained, and the temperature is 1400 ° C. and the sintering time is low. In the case of 5 hours or more, it is not desirable because it is likely that the characteristics are deteriorated due to the coarsening of the oxide, and when the pressure is high, the applied mold and equipment may be dangerous.

  A final oxide dispersion strengthened platinum-gold material is manufactured by performing hot working, cold working and final heat treatment on the sintered body densified by high-temperature pressure molding (S50).

  In the hot working process, it is important to secure a density close to the theoretical density, and as a hot working process applicable for this purpose, hot rolling, hot forging process, etc. can be used. Yes, for oxide dispersion strengthened platinum-gold produced by hot working, it is desirable to have a relative density of 98% or more, but this is the case for materials with a relative density of 98% or less. Even if a relative density of 99% or more is ensured by subsequent cold working, the pores remaining at the time of hot working are not removed, and the final recrystallization heat treatment or the surface of blister (swelling) or the like This is because a defect is likely to occur.

  It is appropriate that the processing temperature during hot processing is 1000 to 1400 ° C. However, when the processing temperature is as low as 1000 ° C or less, cracks are likely to occur during hot processing. This is because the characteristics of the oxide-dispersion strengthened platinum-gold material may deteriorate due to the coarsening of the alloying element for the oxide when it is difficult to ensure the temperature.

  After hot working, it is also desirable to carry out cold working in order to obtain a recrystallized heat-treated structure through thickness control and final heat treatment in order to prevent the occurrence of cracks during cold working.

  The rolling reduction during cold rolling is suitably 40 to 90%. However, when the rolling reduction is 40% or less, the processing stress is low and recrystallization may not occur even after heat treatment. In the case of 90% or more, the material is highly likely to be damaged by a high processing stress.

  As an implementation condition for the recrystallization heat treatment after the cold working, the recrystallization heat treatment is performed in the air for the oxidation of the oxide element, but the heat treatment is performed in a temperature range of 1200 ° C. to 1400 ° C. for 1 to 5 hours. Desirably, the recrystallization of the microstructure may be suppressed when the temperature is 1200 ° C. or less for 1 hour or less, and when the temperature is 1400 ° C. or more for 5 hours or more, the crystal grains and This is because the oxide is coarsened and the high temperature strength may be lowered.

  An ingot 846gr containing 5 wt% Au and 0.3 wt% Zr in the base material Pt was manufactured using a vacuum high frequency induction melting furnace.

In order to prevent the vaporization phenomenon of gold due to the difference between the melting points of platinum and gold in the plasma process, the surface of the manufactured ingot was oxidized at 800 ° C. for 1 hour, followed by platinum alloy powder. In order to manufacture a plasma, a vacuum pump provided in the plasma equipment is used to reduce the pressure to 10 ⁻³ torr, and then plasma is formed using Ar as a reaction gas, and then the ingot is melted to produce a powder. Produced powder was collected inside the chamber and in the quenching section, etc., and finally a powder containing 5 wt% Au and 0.3 wt% Zr was secured in the Pt base material. Pt base material from which carbon was removed by performing a heat treatment at 750 ° C. for 3 hours in the atmosphere to remove carbon contamination due to It won powder containing 5 wt% of Au and 0.3 wt% of Zr in.

  The produced powder is put into a square-shaped carbon mold and heat-treated at 1400 ° C. for 2 hours in an argon (Ar) atmosphere to produce a molded product. A heat treatment was performed in the atmosphere for 1400 ° C. for 3 hours for oxide formation.

  The oxidized test piece was subjected to pressure sintering at a pressure of 20 MPa for 2 hours from 1400 ° C. in order to ensure high density, and 1300 ° C. in the atmosphere to ensure ultra high density. The final oxide dispersion strengthened platinum-gold material was manufactured by performing hot rolling, cold rolling and heat treatment for 3 hours.

As a result of performing ICP analysis to confirm the gold content of the manufactured plate material, it was possible to manufacture a plate material having a gold content close to the target composition of 4.35 wt%. Table 1 shows the results of ICP analysis for confirming the content of zirconium added for the purpose of dispersion strengthening.

  In the case of the powder manufactured from Table 1, the zirconium content as an oxide alloy element represents 0.2162 wt%, and the platinum purity excluding the zirconium content has achieved a high purity of 3N6 or more, and is sufficient. Quality powder production is possible.

  It was also confirmed that the final plate material maintained a high purity of zirconium content of 0.2156 wt% and platinum purity excluding zirconium of 3N6 or higher.

Table 2 shows the production time, relative density, purity, hardness, zirconium (Zr) content and other physical properties produced for each of the produced oxide dispersion strengthened platinum-gold alloys.

  From Table 2, it is possible to produce an oxide dispersion-strengthened platinum-gold material of sufficient quality in two days according to the present invention, and the purity of platinum is very superior to that of a conventionally used material. It can be seen that the zirconium content control is also advantageous.

  In order to confirm the change of the microstructure after heat treatment at 1500 ° C. for 1 hour on the oxide dispersion strengthened platinum-gold material manufactured according to the present invention, the microstructure of the cross-section after the heat treatment The results are shown in FIG.

  Recrystallized grains are observed in the cross section of the oxide dispersion-strengthened platinum-gold material produced according to the present invention, indicating the crystal grains stretched in the rolling direction.

  However, the platinum-gold material manufactured according to the invention shows the fine crystal grains in spite of being subjected to high-temperature heat treatment at 1500 ° C. on both the surface and the cross section. It can be seen that the material dispersion-strengthened platinum-gold material has improved strength by suppressing the growth of crystal grains due to the distribution of fine oxides.

  FIG. 3 shows a comparison result of the contact angle between the oxide dispersion strengthened platinum-gold material manufactured according to the present invention and a conventionally used oxide dispersion strengthened platinum-rhodium alloy melt.

  It can be seen that the contact angle of the oxide dispersion strengthened platinum-gold alloy produced according to the present invention is improved as compared with the oxide dispersion strengthened platinum-rhodium alloy.

Claims (13)

In a manufacturing method for manufacturing an oxide dispersion strengthened platinum-gold alloy for improving the wettability between a glass melt and a platinum-based material during glass manufacturing,
A first step of producing a platinum-gold-oxide alloy ingot by adding gold and an oxide alloy element having a target composition to platinum;
A second stage in which the surface of the platinum-gold-oxide alloy ingot is oxidized before the plasma process, and then a powder is formed using the plasma;
A third stage in which the powder thus produced is subjected to an oxidative heat treatment to produce a molded body having a fixed shape in which the oxide element is oxidized;
A fourth stage for ensuring high density by performing high temperature pressure molding on the oxidized molded body;
Oxide dispersion strengthened type characterized in that it comprises a fifth stage of producing a final oxide dispersion strengthened platinum-gold material by post-processing including any one of hot working, cold working and recrystallization heat treatment A method for producing a platinum-gold alloy.   2. The oxide dispersion according to claim 1, wherein in the first step, a gold content is 1 wt% to 5 wt% among alloy elements added to improve a contact angle with the glass melt. A method for producing a reinforced platinum-gold alloy.   In the first step, the metal element added to the oxide alloying element is any one selected from zirconium (Zr), samarium (Sm), yttrium (Y), and hafnium (Hf). The method for producing an oxide dispersion strengthened platinum-gold alloy according to claim 1.   The amount of the metal element added to the oxide alloy element in the first stage is 0.02 wt% to 0.8 wt%, according to any one of claims 1 to 3. Manufacturing method of oxide dispersion strengthened platinum-gold alloy.   In the second step, before the plasma process, the surface is oxidized to prevent the vaporization of gold during powder production due to the difference between the melting points of platinum and gold, and then plasma is used for platinum-gold-oxide. 2. The method of producing an oxide dispersion strengthened platinum-gold alloy according to claim 1, wherein the alloy powder is produced.   In the third step, the platinum alloy molded body is heat-treated at a temperature of 1000 ° C. to 1400 ° C. for 2 to 5 hours in a vacuum or an inert atmosphere, and subsequently, at a temperature of 1000 ° C. to 1400 ° C. in the atmosphere. The method for producing an oxide dispersion strengthened platinum-gold alloy according to claim 1, wherein the heat treatment is performed for 5 hours.   2. The oxide dispersion strengthening according to claim 1, wherein in the fourth step, the compact is manufactured by hot pressing (HP) or hot isostatic pressing (HIP). Type platinum-gold alloy manufacturing method.   8. The oxide dispersion strengthened platinum according to claim 7, wherein the high pressure molding of the compact is performed at a temperature of 1200 ° C. to 1400 ° C. for 1 to 5 hours and a pressure of 10 MPa to 50 MPa. -Manufacturing method of gold alloy.   2. The method of manufacturing an oxide dispersion strengthened platinum-gold alloy according to claim 1, wherein the fifth step further includes cold working through hot working such as hot rolling or hot forging.   The method of manufacturing an oxide dispersion strengthened platinum-gold alloy according to claim 1, wherein the hot working is performed at a temperature of 1000 ° C to 1400 ° C.   The method for producing an oxide dispersion strengthened platinum-gold alloy according to claim 1, wherein the hot-processed workpiece has a relative density of 98% or more.   2. The method of manufacturing an oxide dispersion strengthened platinum-gold alloy according to claim 1, wherein the cold working is performed at a rolling reduction of 40% to 90%.   2. The oxide dispersion strengthening according to claim 1, wherein the recrystallization heat treatment is performed on the cold-worked platinum alloy material at a temperature of 1200 ° C. to 1400 ° C. for 1 to 5 hours. Type platinum-gold alloy manufacturing method.