CN110676137B - Preparation method of cathode for magnetron - Google Patents

Preparation method of cathode for magnetron Download PDF

Info

Publication number
CN110676137B
CN110676137B CN201910870422.7A CN201910870422A CN110676137B CN 110676137 B CN110676137 B CN 110676137B CN 201910870422 A CN201910870422 A CN 201910870422A CN 110676137 B CN110676137 B CN 110676137B
Authority
CN
China
Prior art keywords
temperature
tungsten
layer
spraying
spiral
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201910870422.7A
Other languages
Chinese (zh)
Other versions
CN110676137A (en
Inventor
漆世锴
王小霞
王兴起
高阳
查兵
刘理
曾伟
徐梦婷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiujiang University
Original Assignee
Jiujiang University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jiujiang University filed Critical Jiujiang University
Priority to CN201910870422.7A priority Critical patent/CN110676137B/en
Publication of CN110676137A publication Critical patent/CN110676137A/en
Application granted granted Critical
Publication of CN110676137B publication Critical patent/CN110676137B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H01J9/04—Manufacture of electrodes or electrode systems of thermionic cathodes
    • H01J9/042—Manufacture, activation of the emissive part
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/02—Electrodes; Magnetic control means; Screens
    • H01J23/04—Cathodes
    • H01J23/05—Cathodes having a cylindrical emissive surface, e.g. cathodes for magnetrons
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/50—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2223/00—Details of transit-time tubes of the types covered by group H01J2225/00
    • H01J2223/02—Electrodes; Magnetic control means; Screens
    • H01J2223/04—Cathodes
    • H01J2223/05—Cathodes having a cylindrical emissive surface, e.g. cathodes for magnetrons
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2225/00—Transit-time tubes, e.g. Klystrons, travelling-wave tubes, magnetrons
    • H01J2225/50—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field

Abstract

A method for preparing a cathode for a magnetron, the method comprising the steps of: (1) sleeving the processed spiral tungsten wire on a cylindrical inner container, uniformly coating an aluminum oxide suspension on the surface of the spiral tungsten wire sleeved with the inner container, drying the spiral tungsten wire in a dryer after each coating, repeating the operation until the thickness of the aluminum oxide layer exceeds the diameter of the spiral tungsten wire, taking out the inner container, and finally putting the inner container into a high-temperature hydrogen furnace for sintering to obtain a heater with good insulating property; (2) uniformly spraying a tungsten powder layer on the surface of the heater by using a high-pressure spray gun, repeatedly spraying and drying, and then putting into a high-temperature hydrogen furnace to sinter to form a tungsten sponge layer; (3) and (3) uniformly spraying electron emission active substances on the surface of the tungsten sponge layer by using a high-pressure spray gun, repeatedly spraying and drying, and then putting into a high-temperature vacuum furnace to sinter to form a ceramic layer, thus preparing the cathode for the magnetron. The cathode prepared by the invention has the advantages of low working temperature, small evaporation, good poisoning resistance and strong electron bombardment resistance.

Description

Preparation method of cathode for magnetron
Technical Field
The invention relates to a preparation method of a cathode for a magnetron.
Background
A magnetron is an electric vacuum device used to generate microwave energy. The tube is a vacuum diode placed in a constant magnetic field, electrons in the tube interact with a high-frequency electromagnetic field under the control of the constant magnetic field and the constant electric field which are perpendicular to each other, and energy obtained from the constant electric field can be converted into microwave energy, so that the aim of generating the microwave energy is fulfilled. Currently, magnetrons have proven to be the most efficient and economical microwave generator for industrial use as a vacuum electronic device. The cathode is one of the heart parts of the magnetron, and the quality of the cathode directly influences the output power and the service life of the magnetron; in the normal working process of the high-power magnetron, the cathode of the high-power magnetron works at a higher temperature and in a worse working environment, the surface of the cathode is bombarded by violent electrons and ions, and the traditional oxide cathode and the barium-tungsten cathode can lose effectiveness.
Disclosure of Invention
The invention aims to provide a method for preparing a cathode for a magnetron, which solves the problems that the conventional high-power magnetron works at a higher temperature and in a worse working environment, the surface of the cathode is bombarded by violent electrons and ions, and the conventional oxide cathode and the conventional barium-tungsten cathode fail in the normal working process.
In order to achieve the above object, the technical scheme is that the preparation method of the cathode for the magnetron comprises the following steps:
(1) sleeving the processed spiral tungsten wire on a cylindrical inner container, uniformly coating an aluminum oxide suspension on the surface of the spiral tungsten wire sleeved with the inner container, drying the spiral tungsten wire in a dryer after each coating, repeating the operation until the thickness of the aluminum oxide layer exceeds the diameter of the spiral tungsten wire, taking out the inner container, and finally putting the inner container into a high-temperature hydrogen furnace for sintering to obtain a heater with good insulating property;
(2) uniformly spraying a tungsten powder layer on the surface of the thermite by using a high-pressure spray gun, repeatedly spraying and drying, and then putting into a high-temperature hydrogen furnace for sintering to form a tungsten sponge layer;
(3) and (3) uniformly spraying electron emission active substances on the surface of the tungsten sponge layer by using a high-pressure spray gun, repeatedly spraying and drying, and then putting into a high-temperature vacuum furnace to sinter to form a ceramic layer, thus preparing the cathode for the magnetron.
Advantageous effects
Compared with the prior art, the invention has the following advantages.
1. The cathode prepared by the invention has the advantages of low working temperature, small evaporation, good poisoning resistance and strong electron bombardment resistance;
2. the invention has simple manufacturing process and lower cost and has better application potential in a high-power magnetron.
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is a flow chart of the cathode preparation of the present invention;
FIG. 2 is a schematic view of the spiral tungsten filament and the inner container of the present invention;
FIG. 3 is EDS spectrum of yttrium zirconate cathode prepared in the first embodiment of the present invention
FIG. 4 is a cross-sectional view of the overall structure of a yttrium zirconate cathode fabricated according to a first embodiment of the present invention;
FIG. 5 is a thermal emission I-V characteristic curve of a yttrium zirconate cathode prepared according to a first embodiment of the invention;
FIG. 6 is a graph of the life characteristics of a yttrium zirconate cathode prepared in accordance with example one of the present invention;
FIG. 7 is an EDS spectrum of a gadolinium hafnate cathode prepared in example two of the present invention;
fig. 8 is a cross-sectional view of the overall structure of a gadolinium hafnate cathode according to a second embodiment of the present invention;
FIG. 9 is a thermal emission I-V characteristic curve of a gadolinium hafnate cathode prepared according to a second embodiment of the present invention;
FIG. 10 is a graph illustrating lifetime characteristics of a gadolinium hafnate cathode prepared according to example two of the present invention;
FIG. 11 is an EDS spectrum of a yttrium hafnate cathode prepared in example three of the present invention;
FIG. 12 is a sectional view showing the overall structure of a yttrium hafnate cathode according to a third embodiment of the present invention;
FIG. 13 is a thermal emission I-V characteristic curve of a yttrium hafnate cathode prepared in example three of the present invention;
fig. 14 is a graph showing the lifetime characteristics of a yttrium hafnate cathode prepared according to example three of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to specific embodiments and accompanying drawings.
A method for preparing a cathode for a magnetron, as shown in fig. 1 and 2, the method comprising the steps of:
(4) sleeving the processed spiral tungsten wire on a cylindrical inner container, uniformly coating an aluminum oxide suspension on the surface of the spiral tungsten wire sleeved with the inner container, drying the spiral tungsten wire in a dryer after each coating, repeating the operation until the thickness of the aluminum oxide layer exceeds the diameter of the spiral tungsten wire, taking out the inner container, and finally putting the inner container into a high-temperature hydrogen furnace for sintering to obtain a heater with good insulating property;
(5) uniformly spraying a tungsten powder layer on the surface of the thermite by using a high-pressure spray gun, repeatedly spraying and drying, and then putting into a high-temperature hydrogen furnace for sintering to form a tungsten sponge layer;
(6) and (3) uniformly spraying electron emission active substances on the surface of the tungsten sponge layer by using a high-pressure spray gun, repeatedly spraying and drying, and then putting into a high-temperature vacuum furnace to sinter to form a ceramic layer, thus preparing the cathode for the magnetron.
The alumina suspension in the step (1) is a mixed solution of 20wt% of alumina powder, 10wt% of (1-3)% of methanol solution and 70wt% of (1-3)% of nitrocotton solution, wherein the purity of the alumina powder is 4N, and the average grain size is less than 1 mu m; the filament diameter of the spiral tungsten filament is 1.2-1.4 mm, the spiral diameter is 8.5-8.7 mm, and the spiral length is 23-27 mm.
The sintering process of the high-temperature hydrogen furnace in the step (1) comprises the following steps: firstly, linearly raising the temperature to 1450-1800 ℃ from the normal temperature within 2-20 minutes, preserving the temperature for 10-30 minutes, and then linearly lowering the temperature to the normal temperature within 2-12 hours to obtain the heater with good insulating property.
And (3) repeatedly spraying and drying the tungsten powder layer in the step (2), wherein the thickness of the tungsten powder layer is 20-200 mu m, the purity of the tungsten powder is 4N, the particle size is 1-2 mu m, the air pressure value adopted by a high-pressure spray gun for spraying the tungsten powder layer is 0.4-0.8 Mpa, after spraying the tungsten powder once, the tungsten powder layer is dried by using a dryer, and then the operation is repeated until the thickness of the tungsten powder layer is 20-200 mu m.
The sintering process of the high-temperature hydrogen furnace in the step (2) comprises the following steps: firstly, linearly raising the temperature to 1500-2000 ℃ from the normal temperature within 0.5-2 hours, preserving the temperature for 0.5-2 hours, and then linearly reducing the temperature to the normal temperature within 2-12 hours to obtain the tungsten sponge layer.
The electron emission active material in the step (3) is one of a yttrium zirconate suspension, a gadolinium hafnate suspension and a yttrium hafnate suspension, wherein the yttrium zirconate suspension is a mixed solution of 20wt% yttrium zirconate powder and 80wt% of (1-3)% nitro-cotton solution, the gadolinium hafnate suspension is a mixed solution of 20wt% gadolinium hafnate powder and 80wt% of (1-3)% nitro-cotton solution, and the yttrium hafnate suspension is a mixed solution of 20wt% yttrium hafnate powder and 80wt% of (1-3)% nitro-cotton solution; the high-pressure spray gun for spraying the electron emission active material adopts an air pressure value of 0.5-1.0 Mpa, and the high-pressure spray gun is dried by a dryer after the electron emission active material is sprayed once, and the operation is repeated.
The sintering process in the high-temperature vacuum furnace in the step (3) comprises the following steps: firstly, linearly heating to 1400-1800 ℃ from 2-4 hours after the normal temperature is consumed, and linearly cooling to the normal temperature from 12-24 hours after heat preservation for 2-7 hours to obtain a ceramic layer; the vacuum degree in the sintering process is always better than 10-5Pa, and the thickness of the finally sintered ceramic layer is 50-300 mu m.
Example one
Yttrium zirconate is used as the electron-emitting active substance.
Sleeving a spiral tungsten wire with the wire diameter of 1.2-1.4 mm, the spiral diameter of 8.5-8.7 mm and the spiral length L of 23-27 mm on the cylindrical inner container; then uniformly coating an aluminum oxide suspension on the surface of the spiral tungsten wire sleeved with the liner, wherein the suspension is a mixed solution of 20wt% of aluminum oxide powder, 10wt% of (1-3)% methanol solution and 70wt% of (1-3)% nitrocotton solution, the purity of the aluminum oxide powder is 4N, and the average particle size is smaller than 1 mu m; drying under a dryer after each coating, and repeating the operation until the thickness of the coated aluminum oxide layer exceeds the diameter of the tungsten spiral wire; taking out the inner container, putting the inner container into a high-temperature hydrogen furnace for sintering, wherein the process comprises the steps of linearly raising the temperature to 1450-1800 ℃ from the normal temperature within 2-20 minutes, preserving the temperature for 10-30 minutes, and then consuming 2-12 hoursLinearly reducing the temperature to normal temperature, and taking out to obtain a heater with good insulating property; then, uniformly and repeatedly spraying a tungsten powder layer on the surface of the thermite by using a high-pressure spray gun, wherein the purity of the tungsten powder is 4N, the particle size is 1-3 mu m, the air pressure value adopted by the high-pressure spray gun is 0.4-0.8 Mpa, drying is carried out by using a dryer after the tungsten powder is sprayed once, the operation is repeated until the thickness of the tungsten powder layer is 20-200 mu m, and the thickness of the tungsten powder layer which is repeatedly sprayed and dried is 20-200 mu m; finally, placing the tungsten spiral wire with the tungsten powder layer sprayed on the surface into a high-temperature hydrogen furnace for sintering, wherein the process comprises the steps of firstly linearly raising the temperature to 1500-2000 ℃ from the normal temperature within 0.5-2 hours, preserving the temperature for 0.5-2 hours, and then linearly lowering the temperature to the normal temperature within 2-12 hours to obtain a tungsten sponge layer; then uniformly and repeatedly spraying a yttrium zirconate suspension on the surface of the tungsten sponge layer by using a high-pressure spray gun, wherein the yttrium zirconate suspension is a mixed solution of 20wt% of yttrium zirconate powder and 80wt% (1-3)% of nitrocotton solution, the air pressure value of the spray gun is 0.5-1.0 Mpa, drying is carried out by using a dryer after the yttrium zirconate suspension is sprayed once, and then the operation is repeated; finally, the mixture is put into a high-temperature vacuum furnace for sintering, and the vacuum degree of the vacuum furnace in the whole sintering process is always superior to 10-5Pa, the sintering process is as follows: linearly heating to 1400-1800 ℃ from the normal temperature within 2-4 hours, preserving the heat for 2-7 hours, and then linearly cooling to the normal temperature within 12-24 hours, thus obtaining a compact and uniform yttrium zirconate ceramic layer, wherein an EDS spectrogram of the yttrium zirconate ceramic is shown in FIG. 3; the thickness of the prepared yttrium zirconate ceramic layer is 50-300 mu m; the novel yttrium zirconate cathode for the magnetron is prepared through the preparation process, and the sectional view of the overall structure of the yttrium zirconate cathode for the magnetron is shown in fig. 4; the yttrium zirconate cathode for the magnetron has larger emission capacity, and can obtain 1.3A/cm at the working temperature of 1600 ℃ and the anode voltage of 300V2As shown in fig. 5; in addition, on a life test bed, the yttrium zirconate cathode for the magnetron of the invention has the anode voltage of 220V at 1500 ℃, and the thermal emission current density of 0.5A/cm2Under the condition, as shown in fig. 6, the service life can reach more than 5000 hours, which is far higher than the 1000-hour service life requirement of the magnetron cathode in actual production.
Example two
Gadolinium hafnate is used as the electron-emitting active substance.
Sleeving a spiral tungsten wire with the wire diameter of 1.2-1.4 mm, the spiral diameter of 8.5-8.7 mm and the spiral length L of 23-27 mm on a cylindrical liner, and then uniformly coating an aluminum oxide suspension on the surface of the spiral tungsten wire sleeved with the liner, wherein the suspension is a mixed solution of 20wt% of aluminum oxide powder, 10wt% of (1-3)% of methanol solution and 70wt% of (1-3)% of nitrocotton solution, the purity of the aluminum oxide powder is 4N, and the average particle size is less than 1 mu m; drying under a dryer after each coating, and repeating the operation until the thickness of the coated aluminum oxide layer exceeds the diameter of the tungsten spiral wire; taking out the inner container, putting the inner container into a high-temperature hydrogen furnace for sintering, wherein the process comprises the steps of linearly raising the temperature to 1450-1800 ℃ from the normal temperature within 2-20 minutes, preserving the temperature for 10-30 minutes, then linearly lowering the temperature to the normal temperature within 2-12 hours, and taking out to obtain the heater with good insulating property; then, uniformly and repeatedly spraying a tungsten powder layer on the surface of the thermite by using a high-pressure spray gun, wherein the purity of the tungsten powder is 4N, the particle size is 1-3 mu m, the air pressure value adopted by the high-pressure spray gun is 0.4-0.8 Mpa, after spraying the tungsten powder once, drying by using a dryer, and finally, putting the tungsten spiral wire with the tungsten powder layer sprayed on the surface into a high-temperature hydrogen furnace for sintering, wherein the process comprises the steps of firstly linearly raising the temperature to 1500-2000 ℃ from the normal temperature for 0.5-2 hours, preserving the temperature for 0.5-2 hours, and then linearly reducing the temperature to the normal temperature for 2-12 hours to obtain a tungsten sponge layer; and then uniformly and repeatedly spraying a gadolinium hafnate suspension on the surface of the tungsten sponge layer by using a high-pressure spray gun, wherein the gadolinium hafnate suspension is a mixed solution of 20wt% gadolinium hafnate powder and 80wt% (1-3)% nitrocotton solution, the air pressure value of the spray gun is 0.5-1.0 Mpa, and after spraying the gadolinium hafnate suspension once, drying by using a dryer, and then repeating the operation. Finally, the mixture is put into a high-temperature vacuum furnace for sintering, and the vacuum degree of the vacuum furnace in the whole sintering process is always superior to 10-5Pa, the sintering process is as follows: linearly increasing the temperature to 1400-1800 ℃ from the normal temperature by consuming 2-4 hours, preserving the temperature for 2-7 hours, and then linearly decreasing the temperature to the normal temperature by consuming 12-24 hours, so as to obtain a relatively compact and uniform gadolinium hafnate ceramic layer, wherein an EDS spectrogram of the gadolinium hafnate ceramic is shown in FIG. 7, and the thickness of the prepared gadolinium hafnate ceramic layer is 50-300 μm; through the preparation process, the product is preparedA novel gadolinium hafnate cathode for a magnetron, as shown in fig. 8, is a cross-sectional view of the overall structure of the gadolinium hafnate cathode for the magnetron; the gadolinium hafnate cathode for the magnetron has large emission capability, and can obtain 2A/cm at the working temperature of 1600 ℃ and the anode voltage of 300V2As shown in fig. 9. In addition, on a life test bed, the gadolinium hafnate cathode for the magnetron of the invention has the anode voltage of 160V and the thermal emission current density of 0.5A/cm at 1500 DEG C2Under the condition, as shown in fig. 10, the service life can reach more than 5000 hours, which is far higher than the 1000-hour service life requirement of the magnetron cathode in the actual production.
EXAMPLE III
Yttrium hafnate is used as the electron-emitting active substance.
Sleeving a spiral tungsten wire with the wire diameter of 1.2-1.4 mm, the spiral diameter of 8.5-8.7 mm and the spiral length L of 23-27 mm on a cylindrical liner, and then uniformly coating an aluminum oxide suspension on the surface of the spiral tungsten wire sleeved with the liner, wherein the suspension is a mixed solution of 20wt% of aluminum oxide powder, 10wt% of (1-3)% of methanol solution and 70wt% of (1-3)% of nitrocotton solution, the purity of the aluminum oxide powder is 4N, and the average particle size is less than 1 mu m; drying under a dryer after each coating, and repeating the operation until the thickness of the coated aluminum oxide layer exceeds the diameter of the tungsten spiral wire; taking out the inner container, putting the inner container into a high-temperature hydrogen furnace for sintering, wherein the process comprises the steps of linearly raising the temperature to 1450-1800 ℃ from the normal temperature within 2-20 minutes, preserving the temperature for 10-30 minutes, then linearly lowering the temperature to the normal temperature within 2-12 hours, and taking out to obtain the heater with good insulating property; then, uniformly and repeatedly spraying a tungsten powder layer on the surface of the thermite by using a high-pressure spray gun, wherein the purity of the tungsten powder is 4N, the particle size is 1-3 mu m, the air pressure value adopted by the high-pressure spray gun is 0.4-0.8 Mpa, after spraying the tungsten powder once, drying by using a dryer, and repeating the operation, wherein the thickness of the tungsten powder layer which is repeatedly sprayed and dried is 20-200 mu m; finally, placing the tungsten spiral wire with the tungsten powder layer sprayed on the surface into a high-temperature hydrogen furnace for sintering, wherein the process comprises the steps of firstly linearly raising the temperature to 1500-2000 ℃ from the normal temperature within 0.5-2 hours, preserving the temperature for 0.5-2 hours, and then linearly lowering the temperature to the normal temperature within 2-12 hours to obtain a tungsten sponge layer; then using high pressureUniformly and repeatedly spraying yttrium hafnate suspension on the surface of the tungsten sponge layer by using a spray gun, wherein the yttrium hafnate suspension is a mixed solution of 20wt% yttrium hafnate powder and 80wt% of (1-3)% nitrocotton solution, the air pressure value of the spray gun is 0.5-1.0 Mpa, drying by using a dryer after spraying the yttrium hafnate suspension once, and repeating the operation; finally, the mixture is put into a high-temperature vacuum furnace for sintering, and the vacuum degree of the vacuum furnace in the whole sintering process is always superior to 10-5Pa, the sintering process is as follows: linearly increasing the temperature to 1400-1800 ℃ from the normal temperature by taking 2-4 hours, preserving the temperature for 2-7 hours, and then linearly decreasing the temperature to the normal temperature by taking 12-24 hours, so as to obtain a relatively compact and uniform yttrium hafnate ceramic layer, wherein an EDS (electron-ray diffraction) spectrogram of the yttrium hafnate ceramic is shown in figure 11, and the thickness of the prepared yttrium hafnate ceramic layer is 50-300 microns; the novel yttrium hafnate cathode for the magnetron is prepared through the preparation process, and fig. 12 is a sectional view of the overall structure of the yttrium hafnate cathode for the magnetron. The yttrium hafnate cathode for the magnetron has larger emission capability, and can obtain 3.5A/cm at the working temperature of 1600 ℃ and the anode voltage of 300V2As shown in fig. 13. In addition, on a life test bed, the yttrium hafnate cathode for the magnetron of the invention has the anode voltage of 300V at 1450 ℃, and the thermal emission current density of 1A/cm2Under the condition, as shown in fig. 14, the service life can reach more than 5000 hours, which is far higher than the 1000-hour service life requirement of the magnetron cathode in actual production.

Claims (1)

1. A method for preparing a cathode for a magnetron, the method comprising the steps of:
(1) sleeving the processed spiral tungsten wire on a cylindrical inner container, and then uniformly coating an aluminum oxide suspension on the surface of the spiral tungsten wire sleeved with the inner container, wherein the aluminum oxide suspension is a mixed solution of 20wt% of aluminum oxide powder, 10wt% of (1-3)% of methanol solution and 70wt% of (1-3)% of nitro-cotton solution, the purity of the aluminum oxide powder is 4N, and the average particle size is smaller than 1 micron; drying the coated aluminum oxide layer under a dryer after each coating, repeating the operation until the thickness of the aluminum oxide layer exceeds the diameter of the spiral tungsten wire, and taking out the liner, wherein the wire diameter of the spiral tungsten wire is 1.2-1.4 mm, the diameter of the spiral is 8.5-8.7 mm, and the length of the spiral is 23-27 mm; and finally, sintering the mixture in a high-temperature hydrogen furnace to obtain a heater with good insulating property, wherein the sintering process of the high-temperature hydrogen furnace comprises the following steps: firstly, linearly raising the temperature to 1450-1800 ℃ from the normal temperature within 2-20 minutes, preserving the temperature for 10-30 minutes, and then linearly lowering the temperature to the normal temperature within 2-12 hours to obtain a heater with good insulating property;
(2) uniformly spraying a tungsten powder layer on the surface of the heater by using a high-pressure spray gun, repeatedly spraying and drying, wherein the thickness of the tungsten powder layer repeatedly sprayed and dried is 20-200 mu m, the purity of the tungsten powder is 4N, the particle size is 1-2 mu m, the air pressure value adopted by the high-pressure spray gun for spraying the tungsten powder layer is 0.4-0.8 Mpa, drying by using a dryer after spraying the tungsten powder once, and repeating the operation until the thickness of the tungsten powder layer is 20-200 mu m; then putting the tungsten sponge layer into a high-temperature hydrogen furnace for sintering to form the tungsten sponge layer, wherein the process of sintering the tungsten sponge layer in the high-temperature hydrogen furnace is as follows: firstly, linearly raising the temperature to 1500-2000 ℃ from the normal temperature within 0.5-2 hours, preserving the temperature for 0.5-2 hours, and then linearly reducing the temperature to the normal temperature within 2-12 hours to obtain a tungsten sponge layer;
(3) uniformly spraying an electron emission active substance on the surface of the tungsten sponge layer by using a high-pressure spray gun, and repeatedly spraying and drying, wherein the electron emission active substance is one of a yttrium zirconate suspension, a gadolinium hafnate suspension and a yttrium hafnate suspension, the yttrium zirconate suspension is a mixed solution of 20wt% of yttrium zirconate powder and 80wt% of (1-3)% of a nitro-cotton solution, the gadolinium hafnate suspension is a mixed solution of 20wt% of gadolinium hafnate powder and 80wt% of (1-3)% of the nitro-cotton solution, and the yttrium hafnate suspension is a mixed solution of 20wt% of yttrium hafnate powder and 80wt% of (1-3)% of the nitro-cotton solution; the high-pressure spray gun for spraying the electron emission active material adopts an air pressure value of 0.5-1.0 Mpa, and the high-pressure spray gun is dried by a dryer after spraying the electron emission active material once, and the operation is repeated. And then placing the ceramic layer into a high-temperature vacuum furnace for sintering to form a ceramic layer, namely preparing the cathode for the magnetron, wherein the sintering process in the high-temperature vacuum furnace is as follows: firstly, linearly heating to 1400-1800 ℃ from 2-4 hours after the normal temperature is consumed, and linearly cooling to the normal temperature from 12-24 hours after heat preservation for 2-7 hours to obtain a ceramic layer; the vacuum degree in the sintering process is always better than 10-5Pa, and the thickness of the finally sintered ceramic layer is 50-300 mu m.
CN201910870422.7A 2019-09-16 2019-09-16 Preparation method of cathode for magnetron Active CN110676137B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910870422.7A CN110676137B (en) 2019-09-16 2019-09-16 Preparation method of cathode for magnetron

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910870422.7A CN110676137B (en) 2019-09-16 2019-09-16 Preparation method of cathode for magnetron

Publications (2)

Publication Number Publication Date
CN110676137A CN110676137A (en) 2020-01-10
CN110676137B true CN110676137B (en) 2022-05-27

Family

ID=69076971

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910870422.7A Active CN110676137B (en) 2019-09-16 2019-09-16 Preparation method of cathode for magnetron

Country Status (1)

Country Link
CN (1) CN110676137B (en)

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2749470A (en) * 1952-06-11 1956-06-05 Int Standard Electric Corp Indirectly heated cathodes
GB1012695A (en) * 1962-10-15 1965-12-08 Philips Electronic Associated Improvements in indirectly-heated electron-tube cathodes
US3246197A (en) * 1962-10-02 1966-04-12 Westinghouse Electric Corp Cathode heater having an aluminum oxide and tungesten coating
JPS50120561A (en) * 1974-02-22 1975-09-20
JPS5693246A (en) * 1979-12-27 1981-07-28 Toshiba Corp Production of magnetron cathode body
JPS6340230A (en) * 1986-08-05 1988-02-20 Toshiba Corp Manufacture of heater of indirectly heated cathode
JPH01279537A (en) * 1988-04-30 1989-11-09 Futaba Corp Indirectly heated linear cathode
CN1052748A (en) * 1989-12-22 1991-07-03 国营国光电子管总厂 Magnetron cathode assembly and manufacture craft
CN1925088A (en) * 2005-08-31 2007-03-07 安徽华东光电技术研究所 Dipped barium wolfram cathode and process for its manufacture
CN101687247A (en) * 2007-07-24 2010-03-31 株式会社东芝 Method for manufacturing coil member and coil member
CN107622931A (en) * 2016-07-14 2018-01-23 中国科学院电子学研究所 A kind of electron gun and gyrotron
CN109037007A (en) * 2018-07-03 2018-12-18 九江学院 A kind of preparation method of the directly-heated type cathode of resistance to electron bombardment
CN109065422A (en) * 2018-07-03 2018-12-21 九江学院 A kind of preparation method of directly-heated type carbonization tungsten-rhenium alloy cathode

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2749470A (en) * 1952-06-11 1956-06-05 Int Standard Electric Corp Indirectly heated cathodes
US3246197A (en) * 1962-10-02 1966-04-12 Westinghouse Electric Corp Cathode heater having an aluminum oxide and tungesten coating
GB1012695A (en) * 1962-10-15 1965-12-08 Philips Electronic Associated Improvements in indirectly-heated electron-tube cathodes
JPS50120561A (en) * 1974-02-22 1975-09-20
JPS5693246A (en) * 1979-12-27 1981-07-28 Toshiba Corp Production of magnetron cathode body
JPS6340230A (en) * 1986-08-05 1988-02-20 Toshiba Corp Manufacture of heater of indirectly heated cathode
JPH01279537A (en) * 1988-04-30 1989-11-09 Futaba Corp Indirectly heated linear cathode
CN1052748A (en) * 1989-12-22 1991-07-03 国营国光电子管总厂 Magnetron cathode assembly and manufacture craft
CN1925088A (en) * 2005-08-31 2007-03-07 安徽华东光电技术研究所 Dipped barium wolfram cathode and process for its manufacture
CN101687247A (en) * 2007-07-24 2010-03-31 株式会社东芝 Method for manufacturing coil member and coil member
CN107622931A (en) * 2016-07-14 2018-01-23 中国科学院电子学研究所 A kind of electron gun and gyrotron
CN109037007A (en) * 2018-07-03 2018-12-18 九江学院 A kind of preparation method of the directly-heated type cathode of resistance to electron bombardment
CN109065422A (en) * 2018-07-03 2018-12-21 九江学院 A kind of preparation method of directly-heated type carbonization tungsten-rhenium alloy cathode

Also Published As

Publication number Publication date
CN110676137A (en) 2020-01-10

Similar Documents

Publication Publication Date Title
US2912611A (en) Thermionic cathodes
EP0179513B1 (en) Method of manufacturing a scandate dispenser cathode and dispenser cathode manufactured by means of the method
CN109037007B (en) Preparation method of directly-heated electron bombardment resistant cathode
CN109065424B (en) Preparation method of rhenium-impregnated scandium-tungsten-based alloy cathode
CN105702542A (en) Rhenium doped tungsten-based alloy cathode and preparation method thereof
CN110676137B (en) Preparation method of cathode for magnetron
CN105304436A (en) Directly heated cathode and preparation method thereof
CN109390195B (en) Scandium-containing cathode at top layer of submicron structure and preparation method thereof
CN109065422B (en) Preparation method of directly-heated high-temperature tungsten-rhenium alloy cathode
CN105810536B (en) Using the magnetron of combined type cold cathode head and the production method of cold cathode body
CN107068517B (en) A kind of magnetron matches the production method for applying cold cathode and cold cathode head
CN108878234B (en) ZrH 2Added Y 2O 3Process for preparing-W-based secondary emitters
CN105788996B (en) A kind of submicron film scandium tungsten cathode and preparation method thereof
CN109926591B (en) Simple preparation method of barium-tungsten cathode
US3015560A (en) Method of fabricating cathode for electron discharge devices
Fu et al. Spherical field emission cathode based on carbon nanotube paste and its application in luminescent bulbs
CN110993465B (en) High current repetition frequency strontium titanate-carbon nano tube medium cathode and preparation method thereof
CN113889388A (en) Pressed cathode and preparation method thereof
US20180254164A1 (en) Carburized La2O3 and Lu2O3 co-doped Mo filament cathode and its fabrication method
Xiao et al. Development of Cathode-grid Assembly for Accelerator Application
KR100235995B1 (en) Impregnation treatment type cathode
CN115101395A (en) Preparation method and application of directly-heated nickel sponge oxide cathode
Wang et al. Research Progress of Pressed Sc 2 O 3 Doped Y-Gd-Hf-O Cathode
JP2699978B2 (en) Traveling wave tube
CN115332026A (en) Cathode assembly capable of being started quickly and preparation method and application thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant