Barium-tungsten cathode material and preparation method thereof

Abstract

The invention relates to the technical field of refractory metal cathode materials, in particular to a barium-tungsten cathode material and a preparation method thereof. The preparation method of the barium-tungsten cathode material comprises the following steps: (1) preparing roughened tungsten powder; (2) preparing doped zirconium oxide powder; (3) mixing raw materials, pressing and forming; (4) sintering a green body; according to the barium-tungsten cathode material disclosed by the invention, the cathode material has relatively high internal porosity while having excellent hardness, so that excellent emission performance is ensured, the problem that the mechanical performance and the porosity of the traditional barium-tungsten cathode material cannot be maintained at excellent levels at the same time is solved, and the barium-tungsten cathode material has a good application prospect in the aspect of the cathode material for a vacuum electronic device. Wide application prospects are realized.

Description

Technical Field

[0001] The invention relates to the technical field of refractory metal cathode materials, and in particular to a barium tungsten cathode material and a preparation method thereof. Background Art

[0002] Vacuum electronic devices are widely used in radar imaging, medical treatment, communication, navigation and other fields. With the development of science and technology, these fields have higher and higher requirements for the application of vacuum electronic devices. When working, vacuum devices realize energy conversion through the action of electrons and magnetic fields, and finally achieve the effect of signal amplification. Therefore, the cathode of the electron emission source plays an important role in vacuum devices. Its quality not only directly affects the performance of vacuum devices, but also determines the reliability and life of the entire device to a considerable extent. For this reason, the cathode is known as the "heart" of vacuum electronic devices.

[0003] Patent document CN1176480C discloses a rare earth scandium tungsten-based high current density electron emitter material and a preparation method thereof. The electron emitter material of the invention has uniform emission performance, improved high temperature resistance and ion bombardment resistance, and the preparation method of the invention has good process repeatability. Patent document CN109926591B discloses a simple preparation method for a barium tungsten cathode. The invention obtains a submicron barium tungsten cathode with good pore structure, and nano-scale active substances appear on the cathode surface, and the emission performance is improved. Although the above cathode materials all have good emission performance, their excellent porosity often adversely affects their mechanical properties in actual applications. Although low-void cathode materials have good mechanical properties, their emission performance is often greatly reduced due to the reduction in porosity. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a barium tungsten cathode material and a preparation method thereof, so as to provide a barium tungsten cathode material with excellent mechanical properties and emission properties.

[0005] Based on the above purpose, the present invention provides a method for preparing a barium tungsten cathode material, comprising the following steps: S1: roughening the tungsten powder to obtain roughened tungsten powder; S2: mixing the roughened tungsten powder and the doped scandium oxide powder, ball milling and dispersing them uniformly, and then pressing to obtain a tungsten cathode green body; S3: sintering the tungsten cathode green body to obtain a tungsten cathode material; S4: coating 411 active salt on the surface of tungsten cathode material, and cooling after high temperature impregnation; S5: washing, drying and annealing the cathode material obtained in S4 to obtain a barium tungsten cathode material; The preparation steps of the doped scandium oxide powder are as follows: Dissolving polyethylene oxide-polystyrene in THF to obtain a polyethylene oxide-polystyrene solution, then dissolving bis(cyclopentadiene)tungsten dichloride in THF to obtain a bis(cyclopentadiene)tungsten dichloride solution, and then dissolving scandium nitrate hexahydrate in THF to obtain a scandium nitrate solution, and then mixing the three, stirring evenly, standing, heat treating, crushing, sieving, and obtaining a doped scandium oxide powder; The particle size of the doped scandium oxide powder is 10-15 μm; The doped scandium oxide powder has a 3D mesoporous structure; Preferably, the specific steps of the roughening treatment in step S1 are first placing the tungsten powder in a sodium hydroxide solution, cleaning it under ultrasonic conditions at 50-75°C for 30 minutes, washing and drying it, and then immersing it in a nitric acid solution for 0.5-1h, filtering, washing, and drying to obtain a roughened tungsten powder.

[0006] Preferably, the molecular weight of the polyethylene oxide-polystyrene is 16,500.

[0007] Preferably, the particle size of the tungsten powder in step S1 is 1-5 μm.

[0008] Preferably, the weight percentage of the roughened tungsten powder and the doped scandium oxide powder in step S2 is 95%-98%: 2%-5%.

[0009] Preferably, in step S2, the ball milling speed is 100-200 rpm, and the ball milling time is 10 min.

[0010] Preferably, the pressing pressure in step S2 is 1.6-2 t / cm 2 , holding time 25-50s.

[0011] Preferably, the sintering in step S3 is microwave-assisted sintering, specifically, first heating to 1000°C at a rate of 30°C / min, keeping warm for 10 minutes, pre-sintering, and then heating to 1400-1500°C at a rate of 40°C / min, keeping warm for 10 minutes.

[0012] Preferably, the coating amount of the 411 active salt in step S4 is 20%-50% of the cathode mass.

[0013] Preferably, the impregnation amount of the 411 active salt in step S4 is more than 8% of the cathode mass.

[0014] Preferably, the composition of the 411 active salt in step S4 is BaO:CaO:Al2O3 in a molar ratio of 4:1:1.

[0015] Preferably, the high temperature immersion time in step S4 is 1-3 minutes, and the immersion temperature is 1600-1700°C.

[0016] Preferably, the annealing temperature in step S5 is 1200°C.

[0017] Preferably, the usage ratio of the polyethylene oxide-polystyrene to THF is 1-2 g:40-60 ml.

[0018] Preferably, the usage ratio of the bis(cyclopentadienyl)tungsten dichloride and THF is 0.5-1g:10-20ml.

[0019] Preferably, the usage ratio of scandium nitrate hexahydrate to THF is 5.3-5.4 g:10-20 ml.

[0020] Furthermore, the present invention also provides a barium tungsten cathode material, and the barium tungsten cathode material is prepared according to the above-mentioned method for preparing the barium tungsten cathode material.

[0021] Beneficial effects of the present invention: The present invention roughens the tungsten powder to achieve better bonding between the raw material powders, making the internal pore distribution of the cathode material more uniform, thereby improving the hardness and emission performance of the cathode material.

[0022] The present invention uses doped zirconium oxide powder with a 3D mesoporous structure as raw material powder, thereby improving the interface compatibility between the components of the raw material powder. At the same time, the mesoporous structure itself further improves the porosity and hardness of the cathode material.

[0023] The cathode material of the present invention is obtained by mixing roughened tungsten powder and doped zirconium oxide powder with a 3D mesoporous structure as raw material powders. The two have a synergistic effect, so that the cathode material has good porosity and thermal emission performance while ensuring excellent hardness. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0025] The properties or amounts of the raw materials used in the examples and comparative examples of the present invention are as follows: The particle size of the tungsten powder is 3 μm; the coating amount of the 411 active salt is 40% of the cathode mass.

[0026] Example 1: A barium tungsten cathode material, the specific preparation steps are as follows: (1) Place the tungsten powder in a 10wt% sodium hydroxide solution, clean it under ultrasonic conditions at 50°C for 30 minutes, rinse it repeatedly with clean water until the pH value is neutral, dry it, and then immerse it in a 10% nitric acid solution for 0.5h, filter it, rinse it repeatedly with clean water until the pH value is neutral, and dry it to obtain a roughened tungsten powder; (2) Dissolve 1 g of polyethylene oxide-polystyrene in 40 ml of THF to obtain a polyethylene oxide-polystyrene solution, then dissolve 0.5 g of bis(cyclopentadiene)tungsten dichloride in 10 ml of THF to obtain a bis(cyclopentadiene)tungsten dichloride solution, and then dissolve 5.3 g of scandium nitrate hexahydrate in 10 ml of THF to obtain a scandium nitrate solution, and then mix the three, stir evenly, and then stand at 25°C for 12 hours, then heat treat at 100°C for 12 hours, and then heat in a nitrogen atmosphere at 1°C / min to 300°C, keep warm for 30 minutes, then heat in an air atmosphere at 5°C / min to 500°C, keep warm for 30 minutes, and finally keep warm at 350°C in an air atmosphere for 2 hours, crush, sieve, and obtain doped scandium oxide powder; (3) Roughened tungsten powder and doped scandium oxide powder were mixed in a weight percentage of 95%:5%, ball milled at 100 rpm for 10 min, loaded into a mold, and pressed in both directions with a steel mold, with the pressure adjusted to 1.6 t / cm 2 , holding time 25s, to obtain a tungsten cathode green body; (4) Sintering the tungsten cathode green body, placing the alumina crucible containing the cathode green body into an auxiliary heat preservation and heating device, and then placing them together into a microwave resonant cavity, first heating to 1000°C at a rate of 30°C / min, keeping the temperature for 10 minutes, pre-sintering, and then heating to 1400°C at a rate of 40°C / min, keeping the temperature for 10 minutes, and naturally cooling to room temperature to obtain a tungsten cathode material; (5) A layer of 411 active salt is uniformly coated on the surface of the tungsten cathode material, and then immersed at 1600°C for 1 minute; then cooled to room temperature with water and taken out; (6) The cathode obtained in step (5) is washed with water, dried, and annealed at 1200° C. to obtain a barium tungsten cathode material.

[0027] Example 2: A barium tungsten cathode material, the specific preparation steps are as follows: (1) The tungsten powder was placed in a 10wt% sodium hydroxide solution, cleaned under ultrasonic conditions at 65°C for 30 minutes, repeatedly rinsed with clean water until the pH value was neutral, dried, and then immersed in a 13% mass concentration nitric acid solution for 1 hour, filtered, repeatedly rinsed with clean water until the pH value was neutral, and dried to obtain a roughened tungsten powder; (2) Dissolve 1.5 g of polyethylene oxide-polystyrene in 50 ml of THF to obtain a polyethylene oxide-polystyrene solution, then dissolve 0.75 g of bis(cyclopentadiene)tungsten dichloride in 15 ml of THF to obtain a bis(cyclopentadiene)tungsten dichloride solution, and then dissolve 5.35 g of scandium nitrate hexahydrate in 15 ml of THF to obtain a scandium nitrate solution, then mix the three, stir evenly, then stand at 25°C for 14 h, then heat treat at 100°C for 13 h, then heat in a nitrogen atmosphere, first increase the temperature to 330°C at 1°C / min, keep warm for 30 min, then increase the temperature to 500°C at 5°C / min, keep warm for 30 min, and finally keep warm at 350°C in an air atmosphere for 3 h, crush, sieve, and obtain doped scandium oxide powder; (3) Roughened tungsten powder and doped scandium oxide powder were mixed in a weight percentage of 96.5%:3.5%, ball milled at 150 rpm for 10 min, and then pressed in a steel mold in both directions, with the pressure adjusted to 1.8 t / cm 2 , the holding time is 40s, and a tungsten cathode green body is obtained; (4) Sintering the cathode green body of tungsten, placing the alumina crucible containing the cathode green body into an auxiliary heat preservation and heating device, and then placing them together into a microwave resonant cavity, first heating to 1000°C at a rate of 30°C / min, keeping the temperature for 10 minutes, pre-sintering, and then heating to 1450°C at a rate of 40°C / min, keeping the temperature for 10 minutes, and naturally cooling to room temperature to obtain a tungsten cathode material; (5) A layer of 411 active salt is uniformly coated on the surface of the tungsten cathode material, and then immersed at 1650°C for 1 minute; then cooled to room temperature with water and taken out; (6) The cathode obtained in step (5) is washed with water, dried, and annealed at 1200° C. to obtain a barium tungsten cathode material.

[0028] Example 3: A barium tungsten cathode material, the specific preparation steps are as follows: (1) Place the tungsten powder in a 10wt% sodium hydroxide solution, clean it under ultrasonic conditions at 75°C for 30 minutes, rinse it repeatedly with clean water until the pH value is neutral, dry it, and then immerse it in a 15% nitric acid solution for 1 hour, filter it, rinse it repeatedly with clean water until the pH value is neutral, and dry it to obtain a roughened tungsten powder; (2) Dissolve 2g of polyethylene oxide-polystyrene in 60ml of THF to obtain a polyethylene oxide-polystyrene solution, then dissolve 1g of di(cyclopentadiene)tungsten dichloride in 20ml of THF to obtain a di(cyclopentadiene)tungsten dichloride solution, and then dissolve 5.4g of scandium nitrate hexahydrate in 20ml of THF to obtain a scandium nitrate solution, and then mix the three, stir evenly, and then stand at 30°C for 15h, then heat treat at 100°C for 14h, and then heat in a nitrogen atmosphere at 1°C / min to 350°C, keep warm for 30min, then heat in an air atmosphere at 5°C / min to 500°C, keep warm for 30min, and finally keep warm at 350°C in an air atmosphere for 3h, crush, sieve, and obtain doped scandium oxide powder; (3) Roughened tungsten powder and doped scandium oxide powder were mixed in a weight percentage of 98%:2%, ball milled at 200 rpm for 10 min, and then pressed in a steel mold in both directions, with the pressure adjusted to 2 t / cm 2 , holding time 50s, to obtain a tungsten cathode green body; (4) Sintering the tungsten cathode green body, placing the alumina crucible containing the cathode green body into an auxiliary heat preservation and heating device, and then placing them together into a microwave resonant cavity, first heating to 1000°C at a rate of 30°C / min, keeping the temperature for 10 minutes, pre-sintering, and then heating to 1500°C at a rate of 40°C / min, keeping the temperature for 10 minutes, and naturally cooling to room temperature to obtain a tungsten cathode material; (5) A layer of 411 active salt is uniformly coated on the surface of the tungsten cathode material, and then immersed at 1700°C for 3 minutes; then cooled to room temperature with water and taken out; (6) The cathode obtained in step (5) is washed with water, dried, and annealed at 1200° C. to obtain a barium tungsten cathode material.

[0029] Comparative Example 1: A barium tungsten cathode material, which differs from Example 2 in that the tungsten powder is not roughened. The specific preparation steps are as follows: (1) Dissolve 1.5 g of polyethylene oxide-polystyrene in 50 ml of THF to obtain a polyethylene oxide-polystyrene solution, then dissolve 0.75 g of bis(cyclopentadiene)tungsten dichloride in 15 ml of THF to obtain a bis(cyclopentadiene)tungsten dichloride solution, and then dissolve 5.35 g of scandium nitrate hexahydrate in 15 ml of THF to obtain a scandium nitrate solution, and then mix the three, stir evenly, and then stand at 25°C for 14 hours, then heat treat at 100°C for 13 hours, and then heat in a nitrogen atmosphere at 1°C / min to 330°C, keep warm for 30 minutes, then heat in an air atmosphere at 5°C / min to 500°C, keep warm for 30 minutes, and finally keep warm at 350°C in an air atmosphere for 3 hours, crush, sieve, and obtain doped scandium oxide powder; (2) Tungsten powder and doped scandium oxide powder were mixed in a weight percentage of 96.5%:3.5%, ball milled at 150 rpm for 10 minutes, and then pressed in a steel mold in both directions, with the pressure adjusted to 1.8 t / cm 2 , the holding time is 40s, and a tungsten cathode green body is obtained; (3) Sintering the cathode green body of tungsten, placing the alumina crucible containing the cathode green body into an auxiliary heat preservation and heating device, and then placing them together into a microwave resonant cavity, first heating to 1000°C at a rate of 30°C / min, keeping the temperature for 10 minutes, pre-sintering, and then heating to 1450°C at a rate of 40°C / min, keeping the temperature for 10 minutes, and naturally cooling to room temperature to obtain a tungsten cathode material; (4) A layer of 411 active salt is uniformly coated on the surface of the tungsten cathode material, and then immersed at 1650°C for 1 minute; then cooled to room temperature with water and taken out; (6) The cathode obtained in step (5) is washed with water, dried, and annealed at 1200° C. to obtain a barium tungsten cathode material.

[0030] Comparative Example 2: A barium tungsten cathode material, which differs from Example 2 in that tungsten is not doped, and the specific preparation steps are as follows: (1) The tungsten powder was placed in a 10wt% sodium hydroxide solution, cleaned under ultrasonic conditions at 65°C for 30 minutes, repeatedly rinsed with clean water until the pH value was neutral, dried, and then immersed in a 13% mass concentration nitric acid solution for 1 hour, filtered, repeatedly rinsed with clean water until the pH value was neutral, and dried to obtain a roughened tungsten powder; (2) Dissolve 1.5 g of polyethylene oxide-polystyrene in 50 ml of THF to obtain a polyethylene oxide-polystyrene solution, then dissolve 5.35 g of scandium nitrate hexahydrate in 15 ml of THF to obtain a scandium nitrate solution, then mix the two, stir evenly, then stand at 25°C for 14 h, then heat treat at 100°C for 13 h, then heat in a nitrogen atmosphere at 1°C / min to 330°C, keep warm for 30 min, then heat in a nitrogen atmosphere at 5°C / min to 500°C, keep warm for 30 min, finally keep warm at 350°C in an air atmosphere for 3 h, crush, sieve, and obtain scandium oxide powder; (3) Roughened tungsten powder and scandium oxide powder were mixed in a weight percentage of 96.5%:3.5%, ball milled at 150 rpm for 10 minutes, and then pressed in a steel mold in both directions, with the pressure adjusted to 1.8 t / cm 2 , the holding time is 40s, and a tungsten cathode green body is obtained; (4) Sintering the cathode green body of tungsten, placing the alumina crucible containing the cathode green body into an auxiliary heat preservation and heating device, and then placing them together into a microwave resonant cavity, first heating to 1000°C at a rate of 30°C / min, keeping the temperature for 10 minutes, pre-sintering, and then heating to 1450°C at a rate of 40°C / min, keeping the temperature for 10 minutes, and naturally cooling to room temperature to obtain a tungsten cathode material; (5) A layer of 411 active salt is uniformly coated on the surface of the tungsten cathode material, and then immersed at 1650°C for 1 minute; then cooled to room temperature with water and taken out; (6) The cathode obtained in step 5 is washed with water, dried, and annealed at 1200° C. to obtain a barium tungsten cathode material.

[0031] Comparative Example 3: A barium tungsten cathode material, which is different from Example 2 in that scandium oxide and tungsten powder are directly mixed and ball-milled, and then mixed with roughened tungsten powder and pressed. The specific preparation steps are as follows: (1) The tungsten powder was placed in a 10wt% sodium hydroxide solution, cleaned under ultrasonic conditions at 65°C for 30 minutes, repeatedly rinsed with clean water until the pH value was neutral, dried, and then immersed in a 13% mass concentration nitric acid solution for 1 hour, filtered, repeatedly rinsed with clean water until the pH value was neutral, and dried to obtain a roughened tungsten powder; (2) Scandium oxide powder with a particle size of 10-15 μm and tungsten powder were mixed in a weight ratio of 7:3, and ball-milled at 700 rpm for 14 h to obtain a sieved doped scandium oxide powder with a particle size of 10-15 μm; (3) Roughened tungsten powder and doped scandium oxide powder were mixed in a weight percentage of 96.5%:3.5%, ball milled at 150 rpm for 10 min, and then pressed in a steel mold in both directions, with the pressure adjusted to 1.8 t / cm 2 , the holding time is 40s, and a tungsten cathode green body is obtained; (4) Sintering the cathode green body of tungsten, placing the alumina crucible containing the cathode green body into an auxiliary heat preservation and heating device, and then placing them together into a microwave resonant cavity, first heating to 1000°C at a rate of 30°C / min, keeping the temperature for 10 minutes, pre-sintering, and then heating to 1450°C at a rate of 40°C / min, keeping the temperature for 10 minutes, and naturally cooling to room temperature to obtain a tungsten cathode material; (5) A layer of 411 active salt is uniformly coated on the surface of the tungsten cathode material, and then immersed at 1650°C for 1 minute; then cooled to room temperature with water and taken out; (6) The cathode obtained in step (5) is washed with water, dried, and annealed at 1200° C. to obtain a barium tungsten cathode material.

[0032] Comparative Example 4: A barium tungsten cathode material, the specific preparation steps are as follows: (1) Tungsten powder and scandium oxide powder were mixed in a weight percentage of 96.5%:3.5%, ball milled at 150 rpm for 10 min, and then pressed in a steel mold in both directions with a pressure of 1.8 t / cm 2 , the holding time is 40s, and a tungsten cathode green body is obtained; (2) Sintering the cathode green body of tungsten, placing the alumina crucible containing the cathode green body into an auxiliary heat preservation and heating device, and then placing them together into a microwave resonant cavity, first heating to 1000°C at a rate of 30°C / min, keeping the temperature for 10 minutes, pre-sintering, and then heating to 1450°C at a rate of 40°C / min, keeping the temperature for 10 minutes, and naturally cooling to room temperature to obtain a tungsten cathode material; (3) A layer of 411 active salt is uniformly coated on the surface of the tungsten cathode material, and then immersed at 1650°C for 1 minute; then cooled to room temperature with water and taken out; (4) The cathode obtained in step (3) is washed with water, dried, and annealed at 1200° C. to obtain a barium tungsten cathode material.

[0033] Performance Testing Hardness: The hardness of the tungsten cathode materials obtained in the embodiment and the comparative example was measured using a MH-6 Vickers microhardness tester. The test results are shown in Table 1. Porosity: The Archimedean drainage method is used to measure the density of the tungsten cathode materials obtained in the examples and comparative examples, and then the porosity of the tungsten matrix is ​​calculated based on the theoretical density of the pure tungsten material and the measured actual density. The calculation formula is as follows: ; P = 1-A Among them, p is the actual density, p1 is the theoretical density, A is the density, and P is the porosity Thermal emission performance: The QX-350 electron emission material testing system was used to test the thermal emission performance of the barium tungsten cathode materials obtained in the embodiment and the comparative example at 950°C. The test results are shown in Table 1.

[0034] Table 1 Performance test results

[0035] Data analysis: It can be seen from Example 2 and Comparative Examples 1 and 2 that when the present invention does not roughen the tungsten powder, its porosity will be slightly improved, but its hardness and emission performance will decrease to a certain extent, which may be due to the uneven distribution of tungsten powder and doped scandium oxide powder; the present invention then roughens the tungsten powder and mixes it with doped scandium oxide powder, and the obtained cathode material has better hardness and emission performance. This is mainly because the larger specific surface area of ​​the roughened tungsten powder and the doped scandium oxide powder can improve the interface compatibility of the surfaces of the two, thereby making the two more evenly and tightly dispersed. At the same time, the two are dispersed more evenly and tightly, so that the pore size inside the cathode material is smaller and more uniform, the specific surface area of ​​the pores is larger, it can carry more barium elements, and can ensure that the barium element is more evenly dispersed inside the material, thereby improving the emission performance of the cathode material.

[0036] It can be seen from Example 2 and Comparative Example 3 that the cathode material prepared by mixing doped zirconia powder with a mesoporous structure and tungsten powder in the present invention has relatively excellent hardness and thermal emission performance. This may be because the doped zirconia powder with a mesoporous structure can provide more pores for the cathode material, and these pores can provide a larger specific surface area, so that more barium elements are evenly loaded on the surface of the pores, thereby further improving its emission performance. At the same time, the frame-like structure inside the doped zirconia powder with a mesoporous structure can ensure the hardness of the cathode material.

[0037] It can be seen from Example 2 and Comparative Example 4 that the present invention performs surface roughening treatment on tungsten powder and doping modification on zirconium oxide powder, which have a synergistic effect, and together enable the cathode material to have uniform and tight distribution of pores inside the cathode material while ensuring excellent hardness, forming a sponge-like structure, and evenly load the barium element on the surface of the pores, thereby ensuring its thermal emission performance.

[0038] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A method for preparing a barium tungsten cathode material, characterized in that: The following steps are involved: S1: roughening the tungsten powder to obtain roughened tungsten powder; S2: mixing the roughened tungsten powder and the doped scandium oxide powder, ball milling and dispersing them uniformly, and then pressing to obtain a tungsten cathode green body; S3: sintering the tungsten cathode green body to obtain a tungsten cathode material; S4: coating 411 active salt on the surface of tungsten cathode material, and cooling after high temperature impregnation; S5: washing, drying and annealing the cathode material obtained in S4 to obtain a barium tungsten cathode material; The preparation steps of the doped scandium oxide powder are as follows: Dissolving polyethylene oxide-polystyrene in THF to obtain a polyethylene oxide-polystyrene solution, then dissolving bis(cyclopentadiene)tungsten dichloride in THF to obtain a bis(cyclopentadiene)tungsten dichloride solution, and then dissolving scandium nitrate hexahydrate in THF to obtain a scandium nitrate solution, and then mixing the three, stirring evenly, standing, heat treating, crushing, sieving, and obtaining a doped scandium oxide powder; The particle size of the doped scandium oxide powder is 10-15 μm, and the doped scandium oxide powder has a 3D mesoporous structure.

2. The method for preparing the barium tungsten cathode material according to claim 1, characterized in that: The specific steps of the roughening treatment in step S1 are to first place the tungsten powder in a sodium hydroxide solution, clean it under ultrasonic conditions at 50-75°C for 30 minutes, wash and dry it, then immerse it in a nitric acid solution for 0.5-1h, filter, wash and dry it to obtain a roughened tungsten powder.

3. The method for preparing the barium tungsten cathode material according to claim 1, characterized in that: The particle size of the tungsten powder in step S1 is 1-5 μm.

4. The method for preparing the barium tungsten cathode material according to claim 1, characterized in that: The weight percentages of the roughened tungsten powder and the doped scandium oxide powder in step S2 are 95%-98%: 2%-5%.

5. The method for preparing the barium tungsten cathode material according to claim 1, characterized in that: The pressing pressure in step S2 is 1.6-2t / cm 2 , holding time 25-50s.

6. The method for preparing the barium tungsten cathode material according to claim 1, characterized in that: The sintering in step S3 is microwave-assisted sintering, specifically, first heating to 1000°C at a rate of 30°C / min, keeping warm for 10 minutes, pre-sintering, and then heating to 1400-1500°C at a rate of 40°C / min, keeping warm for 10 minutes.

7. The method for preparing the barium tungsten cathode material according to claim 1, characterized in that: The coating amount of the 411 active salt in step S4 is 20%-50% of the cathode mass.

8. The method for preparing the barium tungsten cathode material according to claim 1, characterized in that: The high temperature immersion time in step S4 is 1-3 minutes, and the immersion temperature is 1600-1700°C.

9. The method for preparing the barium tungsten cathode material according to claim 1, characterized in that: The usage ratio of the polyethylene oxide-polystyrene to THF is 1-2g:40-60ml; the usage ratio of the bis(cyclopentadiene)tungsten dichloride to THF is 0.5-1g:10-20ml; and the usage ratio of the scandium nitrate hexahydrate to THF is 5.3-5.4g:10-20ml.

10. A barium tungsten cathode material, characterized in that: The barium tungsten cathode material is prepared according to the method for preparing the barium tungsten cathode material according to any one of claims 1-9.

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