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CN-117448612-B - Method for improving density of platinum-based powder metallurgy alloy

CN117448612BCN 117448612 BCN117448612 BCN 117448612BCN-117448612-B

Abstract

The invention relates to a method for improving the compactness of a platinum-based powder metallurgy alloy, which realizes the purposes of reducing the porosity of a noble metal powder metallurgy alloy ingot, improving the compactness of a material through the processes of vacuum melting, powder preparation, resonance compaction, liquid phase sintering, forging control and the like. By adopting the process, the invention greatly improves the lasting strength and toughness of the platinum-based powder metallurgy alloy at high temperature, remarkably prolongs the service life of the product at high temperature and brings good economic benefit.

Inventors

  • WANG ZHIJIANG
  • SONG ZHENYANG
  • SHI WEIFENG
  • LU WEIDING
  • LI XIGUO

Assignees

  • 英特派铂业股份有限公司

Dates

Publication Date
20260508
Application Date
20231027

Claims (6)

  1. 1. A method for improving the compactness of a platinum-based powder metallurgy alloy, which is characterized by comprising the following steps: 1.1, vacuum smelting, namely putting prepared platinum and alloy elements into a vacuum induction furnace for smelting, wherein a smelting crucible is a zirconia crucible, and smelting and casting into a special mould to obtain an alloy cast ingot; 1.2, preparing the obtained cast ingot, namely placing the cast ingot into a plasma rotary powder manufacturing device to prepare platinum-based alloy powder with the required granularity and realizing synchronous oxidation, wherein the rotating speed of the plasma rotary powder manufacturing device is 10000-60000 r/min, the granularity is 20-100 mu m, and the oxygen partial pressure is 1-6 multiplied by 10 4 Pa; 1.3 resonance compaction, namely removing large-particle residues after platinum-based alloy powder is obtained, weighing the powder with uniform residual particle size, and putting the powder into high-frequency resonance equipment for compaction, wherein the resonance frequency is 1000-5000 Hz, and the weight is 3-10 kg; 1.4 liquid phase sintering, namely, the compacted powder and a die are fed into a vacuum high-temperature furnace and undergo a pressurizing molding, vacuum degassing and liquid phase sintering process to obtain a finished ingot, wherein the vacuum degree in the vacuum degassing process is less than or equal to 0.03Pa, and the liquid phase sintering temperature is 1700-1800 ℃; And 1.5, controlling forging, namely performing multi-pass free forging on the finished ingot obtained in the step 1.4 by controlling forging means to obtain a blank, and then preparing the blank into various plate, sheet, rod and wire products by conventional processing means, wherein the initial forging temperature in the multi-pass free forging process is 1400-1500 ℃, the final forging temperature is 1100-1200 ℃, the per-forging processing amount in each pass is 5-10%, 10-15% and finally 5-10%, and the free forging of each pass is performed according to the rule.
  2. 2. The method for improving the compactness of a platinum-based powder metallurgy alloy according to claim 1, wherein the alloy element in the step 1.1 is one or more selected from Rh, au, al, zr, Y, sc, pd.
  3. 3. The method for improving the compactness of the platinum-based powder metallurgy alloy according to claim 1, wherein in the step 1.1, the smelting temperature is 1800-2000 ℃, the smelting time is 20-30 min, the exhausting time is 20-30 min, and the refining time is 5-10 min, so that the liquid metal before casting is obtained.
  4. 4. The method for improving the compactness of a platinum-based powder metallurgy alloy according to claim 1, wherein the prepared platinum and alloy elements in the step 1.1 are platinum ingots meeting the SM/Pt-99.95% standard, rhodium powder meeting the SM/Rh-99.95% standard and zirconium rods with the purity of 99.9%.
  5. 5. An alloy product made by the method of any one of claims 1-4.
  6. 6. The alloy product of claim 5, wherein the maximum density of the alloy product is increased to 99.93% and the creep time is increased to <48h.

Description

Method for improving density of platinum-based powder metallurgy alloy Technical Field The invention relates to a method for improving the density of a platinum-based powder metallurgy alloy, in particular to the technical field of metal material smelting. Background The platinum-based alloy is widely applied to the field of high-end glass industrial manufacturing, has extremely bad use environment, needs to bear long-time scouring, corrosion and cold-hot impact of a high-temperature glass solution of 1200-1650 ℃, and causes serious creep and fatigue of materials. In recent years, new technology is continuously introduced to improve the high-temperature mechanical property, corrosion resistance and oxidation resistance of the platinum-based alloy, wherein the powder metallurgy technology is one of the great effects. At present, by adopting a dispersion strengthening principle and a powder metallurgy technology, the high-temperature strength of the platinum-based alloy can be improved by more than 150%, and the creep property can be improved by more than 300%. However, the platinum-based powder metallurgy alloy prepared by the powder metallurgy means such as an atomization method, an electric spark method and the like commonly used at present has certain defects in density, and can bring about great hidden danger in use. At present, the density of the platinum-based powder metallurgy alloy material prepared by different technological means is detected to be 99.76%, which leads to that a certain number of pores or cavities are necessarily reserved in the product, and the pores or cavities can be expanded, aggregated and extended to finally generate cracking or even complete cracking when the alloy material is used for a long time under a high-temperature working condition. Disclosure of Invention The invention aims to overcome the defects and provide a method for improving the density of platinum-based powder metallurgy alloy, which is used for finally preparing the platinum-based powder metallurgy alloy materials with different sizes through the processes of vacuum melting, powder preparation, resonance compaction, liquid phase sintering, controlled forging and the like. On the other hand, the invention also provides an alloy product or alloy material prepared by the method for improving the compactness of the platinum-based powder metallurgy alloy. The basic principle and advantages of the invention are as follows: (1) And preparing micron-sized platinum-based alloy powder which is uniform in particle size, high in sphericity and directly dried by adopting plasma rotary electrode powder making equipment at a high rotating speed, and simultaneously adjusting oxygen partial pressure to enable the powder to be oxidized synchronously in the preparation process. The method greatly shortens the drying and oxidizing time, and the prepared powder can be directly used for the next step; (2) The macroscopic and microscopic vibration flows are generated in the powder at the same time through the acousto-magnetic coupling field, so that the purposes of self-filling and redispersion of the powder are achieved, and the pellets to be sintered are orderly arranged and compactly combined; (3) The innovative use of liquid phase sintering technology, vacuum degassing in a vacuum high temperature furnace is carried out firstly, and after the vacuum degree reaches below 0.03Pa, the pressurization molding and the near melting point, namely liquid phase sintering, are continuously realized, so as to obtain a preliminary finished ingot with extremely high density; (4) After repeated verification, a group of process schemes for further improving the density of the finished ingot and reducing internal defects by using a free forging method are obtained. Specifically, the technical scheme adopted by the invention is as follows: a method for improving the compactness of a platinum-based powder metallurgy alloy, comprising the following steps: 1.1, vacuum smelting, namely putting prepared platinum and alloy elements into a vacuum induction furnace for smelting, wherein a smelting crucible is a zirconia crucible, and smelting and casting into a special mould to obtain an alloy cast ingot; 1.2, preparing the powder, namely placing the obtained cast ingot into plasma rotary powder-making equipment to prepare platinum-based alloy powder with required granularity and realizing synchronous oxidation; 1.3 resonance compaction, namely, after platinum-based alloy powder is obtained, large-particle residues are removed through screening, and the powder with uniform residual particle size is weighed and put into high-frequency resonance equipment for compaction; 1.4 liquid phase sintering, namely, the powder after compaction and the die enter a vacuum high-temperature furnace together and undergo the processes of pressure molding, vacuum degassing and liquid phase sintering to obtain a finished ingot; and 1.5, controlling forging, namely, perform