CN117344190A - High-entropy alloy reinforced impregnated cathode and preparation method thereof - Google Patents
High-entropy alloy reinforced impregnated cathode and preparation method thereof Download PDFInfo
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- CN117344190A CN117344190A CN202311242435.2A CN202311242435A CN117344190A CN 117344190 A CN117344190 A CN 117344190A CN 202311242435 A CN202311242435 A CN 202311242435A CN 117344190 A CN117344190 A CN 117344190A
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- 239000000956 alloy Substances 0.000 title claims abstract description 30
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 29
- 238000002360 preparation method Methods 0.000 title abstract description 7
- 239000000843 powder Substances 0.000 claims abstract description 29
- 238000010438 heat treatment Methods 0.000 claims abstract description 12
- 239000001257 hydrogen Substances 0.000 claims abstract description 12
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 12
- 238000000034 method Methods 0.000 claims abstract description 12
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052762 osmium Inorganic materials 0.000 claims abstract description 11
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 10
- 238000002156 mixing Methods 0.000 claims abstract description 9
- 238000000498 ball milling Methods 0.000 claims abstract description 7
- 239000002994 raw material Substances 0.000 claims abstract description 7
- 229910052707 ruthenium Inorganic materials 0.000 claims abstract description 6
- 238000009837 dry grinding Methods 0.000 claims abstract description 4
- 238000000227 grinding Methods 0.000 claims abstract description 4
- 238000000465 moulding Methods 0.000 claims abstract description 4
- 238000009702 powder compression Methods 0.000 claims abstract description 4
- 150000003839 salts Chemical class 0.000 claims abstract description 4
- 238000005245 sintering Methods 0.000 claims abstract description 4
- 238000005303 weighing Methods 0.000 claims abstract description 3
- 239000007789 gas Substances 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 3
- 238000000746 purification Methods 0.000 claims description 3
- 229910000905 alloy phase Inorganic materials 0.000 claims description 2
- 238000000137 annealing Methods 0.000 claims description 2
- 238000003825 pressing Methods 0.000 claims description 2
- 229910052702 rhenium Inorganic materials 0.000 claims description 2
- 238000001228 spectrum Methods 0.000 claims description 2
- 239000011159 matrix material Substances 0.000 abstract description 10
- 239000006104 solid solution Substances 0.000 abstract description 5
- 238000005470 impregnation Methods 0.000 abstract description 4
- 238000002844 melting Methods 0.000 abstract description 3
- 230000008018 melting Effects 0.000 abstract description 3
- 150000002431 hydrogen Chemical class 0.000 abstract 1
- 239000000306 component Substances 0.000 description 10
- 238000011161 development Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000013461 design Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 229910000765 intermetallic Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910000510 noble metal Inorganic materials 0.000 description 2
- WMTSAHAFZXEJBV-UHFFFAOYSA-N [Ba].[W] Chemical compound [Ba].[W] WMTSAHAFZXEJBV-UHFFFAOYSA-N 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000010849 ion bombardment Methods 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C30/00—Alloys containing less than 50% by weight of each constituent
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/14—Treatment of metallic powder
- B22F1/142—Thermal or thermo-mechanical treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/02—Compacting only
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/1003—Use of special medium during sintering, e.g. sintering aid
- B22F3/1007—Atmosphere
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
- B22F3/26—Impregnating
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/32—Secondary-electron-emitting electrodes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
- B22F2009/043—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by ball milling
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Abstract
A high-entropy alloy reinforced impregnated cathode and a preparation method thereof belong to the field of refractory high-entropy alloy. The method comprises the following specific steps: 1) Os, ir, re, W and Ru raw material powders were put into a crucible and annealed in hydrogen. Weighing raw material powder and mixing; 2) Mixing evenly by ball milling and dry milling; 3) Powder compression molding: placing the ball-milled powder into a grinding tool to be pressed, and maintaining the pressure for 20-43 s; 4) Sintering the pressed green body in a hydrogen furnace, introducing hydrogen, heating to 850 ℃ for 30min, heating to 1380-1620 ℃ at a heating rate of 8.5 ℃/min, and preserving heat for 15-55 min; impregnating the active salt at 1660-1690 ℃. The impregnated cathode has the cathode matrix with a tissue structure mainly comprising a simple Hcp solid solution, and has the advantages of high melting point, large impregnation amount, high temperature stability, high current emission density and the like.
Description
Technical Field
The invention relates to a high-entropy alloy reinforced impregnated cathode and a preparation method thereof, belonging to the field of refractory high-entropy alloy.
Background
Cathode is a core component of vacuum electronic devices such as cathode ray tube, X-ray tube and microwave tube, and the development progress of cathode technology also determines the development progress of vacuum electronic devices to a great extent, and at present, vacuum electronic devices mainly develop in the directions of high power, high efficiency, high reliability, high frequency and miniaturization. Currently, in high-frequency high-power vacuum electronic devices, electron sources mainly comprise barium-tungsten diffusion cathodes, the cathodes usually work at a temperature below 1000 ℃ and have an emission current density of 5A/cm 2 Left and right. The cathode of the mixed matrix of W-Ir, W-Os and W-Re added with noble metal has strong poisoning resistance and certain ion bombardment resistance, however, the emission current density of the cathode is only 10A/cm when the cathode works at 1000 DEG C 2 Left and right. Although the cathode added with noble metal has lower work function, stronger emission capability and current density of 5-10A/cm 2 Has a long life of more than 20000 hours. However, when pursuing a value of more than 20A/cm 2 When the current density is increased, the working temperature of the cathode is inevitably increased, and the high temperature causes excessive evaporation of the active material, so that the service life of the cathode is seriously shortened, and the practicability of the cathode is greatly influenced. In addition, the film-coated cathode coated with metals such as Os, ir or Re and the like, which has the emission performance equivalent to that of the mixed-base cathode, has the problems that the emission performance of the cathode is reduced and the film layer is easy to fall off due to the fact that components are changed due to the mutual diffusion between matrix elements and film-coated elements in the long-time use process, and the emission performance is unstable. Thus, there is an urgent need for a new cathode to meet the requirements of high power devices for cathode development. In addition, pure tungsten or withThe toughness of the cathode of the intermetallic matrix is poor and the brittleness is large, which makes the cathode processing very difficult.
The high-entropy alloy is a novel alloy material developed in recent years. The method is characterized in that: comprising 5 or more than 5 components, and each component content is between 5% and 35%. Thereafter, the composition range of the high-entropy alloy is further expanded to include 4 or more components, and each component content is between 5% and 50%. The high-entropy alloy does not form a plurality of intermetallic compound phases after solidification, but forms a tissue structure mainly comprising a simple Fcc, bcc or Hcp solid solution. The formation of solid solution matrix makes the high entropy alloy overcome the inherent brittleness of intermetallic compounds and amorphous alloys, so that the high entropy alloy is hopeful to become an advanced engineering structural material.
Therefore, the high-entropy alloy is introduced into the cathode matrix, so that the mechanical property of the cathode is expected to be improved, and the electron emission capability of the cathode can be obviously improved.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a high-entropy alloy reinforced impregnated cathode and a preparation method thereof, wherein the high-entropy alloy is introduced into a cathode matrix to improve the microstructure of the cathode matrix, so that the cathode matrix with a tissue structure mainly comprising a simple Hcp solid solution is obtained, and the cathode with a high melting point and a large impregnation amount is finally obtained.
The invention provides an Os-Ir-Re-W-Ru high-temperature high-entropy alloy, which consists of Os, ir, re, W, ru four or five elements according to equal atomic ratio or non-equal atomic ratio, wherein each element is proportioned according to 5-50% of mole percent, and the chemical formula is Os x Ir y Re z W k Ru n Wherein x+y+z+k+n=100, x, y, z, k, n are each 5 to 50, or either one of x, y, z, k, n is 0, and the others are each 5 to 50;
a high-entropy alloy reinforced impregnated cathode and a preparation method thereof specifically comprises the following steps:
(1) Respectively separating Os, ir, re, W and Ru raw materialsPlacing the powder into a crucible, and annealing in a tube furnace into which hydrogen is introduced to ensure the purification of the original powder; according to Os x Ir y Re z W k Ru n The Os, ir, re, W and Ru raw material powder with required mass are weighed and mixed according to the dosage proportion of each element in the components; mixing materials with Os powder of 200 meshes, ir powder of 200 meshes, re powder of 200 meshes, W powder of 2.3 mu m and Ru powder of 200 meshes;
(2) Uniformly mixing the multi-component powder by using a ball milling method, adopting a dry milling method, and adopting inert gas protection or vacuum;
(3) Powder compression molding: placing the powder obtained after ball milling in the step (2) into a grinding tool (preferably with the diameter of 3 mm) for pressing, and maintaining the pressure for 20-43 s;
(4) Sintering the green body pressed in the step (3) in a hydrogen furnace, introducing hydrogen as a protective gas, heating to 850 ℃ for 30min, heating the sample to 1380-1620 ℃ at a heating rate of 8.5 ℃/min, and preserving heat for 15-55 min; the active salt is impregnated at 1660-1690 ℃ to obtain the high-entropy alloy reinforced impregnated cathode.
The further high-entropy alloy reinforced impregnated cathode XRD spectrum consists of W and high-entropy alloy phase Hcp, and the cathode has optimal thermionic emission performance and can further improve the current emission density.
The preparation method of the high-entropy alloy reinforced impregnated cathode, which is disclosed by the invention, particularly uses a simple Hcp solid solution as a main cathode matrix combined with a single-phase W tissue structure, has the advantages of high melting point, large impregnation amount, high temperature stability, high current emission density and the like, and finally obtains the high-intensity high-emission high-entropy alloy reinforced impregnated cathode.
Drawings
FIG. 1 shows Os of the present invention 16 Ir 25 Re 24 W 35 And Os (sic) 17 Ir 35 Re 18 W 25 Ru 5 XRD profile of the cathode;
FIG. 2 shows Os of the present invention 25 Ir 25 Re 25 W 25 、Os 20 Ir 20 Re 20 W 20 Ru 20 And Os (sic) 30 Ir 35 Re 12 W 13 Ru 10 XRD profile of the cathode;
FIG. 3 shows Os of the present invention 20 Ir 20 Re 20 W 20 Ru 20 SEM images of cathode surface morphology;
FIG. 4 is a graph of the macroscopic morphology of the high entropy alloy strengthened impregnated cathode of the present invention;
FIG. 5 shows Os of the present invention 20 Ir 20 Re 20 W 20 Ru 20 Cathode emission current density;
table 1 shows the design parameters of the components of the present invention;
table 2 shows the temperatures of 1000℃for the cathodes according to the invention b Electron emission performance was tested below.
Detailed Description
The invention will be described in further detail with reference to specific embodiments, but the scope of the invention is not limited to the description.
Composition design
(1) Os, ir, re, W and Ru raw material powders are respectively put into a crucible and are annealed in a tube furnace into which hydrogen is introduced to ensure the purification of the raw powder. Proportioning metal powder with purity of over 99.95%, weighing Os, ir, re, W of required mass and Ru raw material powder according to a proportion, and mixing;
(2) Uniformly mixing the multi-component powder by using a ball milling method, adopting a dry milling method, and adopting inert gas protection or vacuum;
(3) Powder compression molding: putting the powder after ball milling in the step 2 into a grinding tool with the diameter of 3mm to be pressed, and maintaining the pressure for 20-43 s;
(4) Sintering the green compact pressed in the step 3 in a hydrogen furnace, introducing hydrogen as a protective gas, heating to 850 ℃ for 30min, heating the sample to 1490 ℃ at a heating rate of 8.5 ℃/min, and preserving heat for 30min; impregnating the active component 411 salt with electron emission at 1660-1670 ℃.
(5) And placing the cathode prepared by the steps in a flat diode structure to test the pulse current emission density.
Table 1 the present invention relates to 5 high entropy alloy reinforced impregnated cathode composition ratios (atomic percent)
| Sequence number | Os | Ir | Re | W | Ru |
| G1 | 16 | 25 | 24 | 35 | 0 |
| G2 | 25 | 25 | 25 | 25 | 0 |
| G3 | 17 | 35 | 18 | 25 | 5 |
| G4 | 20 | 20 | 20 | 20 | 20 |
| G5 | 30 | 35 | 12 | 13 | 10 |
Table 2 shows that the invention relates to 5 high entropy alloy reinforced impregnated cathodes at 1000deg.C b Current emission density tested below.
| Sequence number | Porosity/% | Impregnation level/% | Current emission density (A/cm) 2 ) |
| G1 | 25.79 | 7.13 | 19.46 |
| G2 | 26.48 | 7.41 | 5.43 |
| G3 | 26.98 | 7.52 | 10.73 |
| G4 | 25.83 | 7.68 | 20.53 |
| G5 | 26.12 | 7.64 | 7.29 |
。
Claims (4)
1. A high-Wen Gaoshang alloy is prepared from Os, ir, re, W, ru four or five elements (5-50 mol.%) in terms of equiatomic ratio or non-equiatomic ratio, and is expressed as Os x Ir y Re z W k Ru n Where x+y+z+k+n=100, x, y, z, k, n are each 5 to 50, or either one of x, y, z, k, n is 0, and the others are each 5 to 50.
2. A method for preparing a high Wen Gaoshang alloy reinforced impregnated cathode according to claim 1, wherein: the method comprises the following steps:
(1) Respectively placing Os, ir, re, W and Ru raw material powder into a crucible, and performing annealing treatment in a tube furnace with hydrogen introduced to ensure the purification of the raw powder; according to Os x Ir y Re z W k Ru n The dosage proportion of each element in the components is used for weighing the Os, ir,Mixing Re, W and Ru raw material powder; mixing materials with Os powder of 200 meshes, ir powder of 200 meshes, re powder of 200 meshes, W powder of 2.3 mu m and Ru powder of 200 meshes;
(2) Uniformly mixing the multi-component powder by using a ball milling method, adopting a dry milling method, and adopting inert gas protection or vacuum;
(3) Powder compression molding: placing the powder obtained after ball milling in the step (2) into a grinding tool (preferably with the diameter of 3 mm) for pressing, and maintaining the pressure for 20-43 s;
(4) Sintering the green body pressed in the step (3) in a hydrogen furnace, introducing hydrogen as a protective gas, heating to 850 ℃ for 30min, heating the sample to 1380-1620 ℃ at a heating rate of 8.5 ℃/min, and preserving heat for 15-55 min; the active salt is impregnated at 1660-1690 ℃ to obtain the high-entropy alloy reinforced impregnated cathode.
3. The Os of claim 1 x Ir y Re z W k Ru n The high-entropy alloy is characterized in that the high-entropy alloy reinforced impregnated cathode XRD spectrum consists of W and a high-entropy alloy phase Hcp, the cathode has optimal thermionic emission performance, and the current emission density can be improved.
4. An impregnated cathode prepared according to the method of claim 2 or 3.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311242435.2A CN117344190A (en) | 2023-09-25 | 2023-09-25 | High-entropy alloy reinforced impregnated cathode and preparation method thereof |
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| CN202311242435.2A CN117344190A (en) | 2023-09-25 | 2023-09-25 | High-entropy alloy reinforced impregnated cathode and preparation method thereof |
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| CN117344190A true CN117344190A (en) | 2024-01-05 |
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- 2023-09-25 CN CN202311242435.2A patent/CN117344190A/en active Pending
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