Preparation method of scandia-doped dispenser cathode material with turned surface

A cathode and car-making technology is applied in the field of preparation of scandium-containing diffusion surface car-made cathode materials, and can solve the problems of restricting the large-scale application of scandium-containing diffusion cathodes and the like

Active Publication Date: 2016-07-27
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above problems limit the large-scale applic

Method used

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  • Preparation method of scandia-doped dispenser cathode material with turned surface
  • Preparation method of scandia-doped dispenser cathode material with turned surface
  • Preparation method of scandia-doped dispenser cathode material with turned surface

Examples

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Effect test

Embodiment 1

[0017] Example 1 Dissolve 146.7g of ammonium metatungstate and 16.7g of scandium nitrate in water respectively, stir well and then mix. Powder was prepared by spray drying, and the powder was calcined and decomposed in a muffle furnace at 600°C for 2 hours. The decomposed product is reduced with hydrogen in a tube furnace. The reduction temperature is slowly heated from room temperature to 600°C, kept for 1 hour, continued to be slowly heated to 950°C, kept for 1 hour, and then slowly cooled. After that, pressing, sintering and impregnation are carried out, and the sintering temperature is 1450°C. Afterwards, the cathode is machined, and the cathode is processed into a cylindrical cathode with a diameter of 2mm and a thickness of 2mm (see figure 1 ). Place the prepared cathode in 2% dilute nitric acid aqueous solution for 15 seconds and wash it with deionized water and absolute ethanol. Afterwards, the cathode was placed in a hydrogen atmosphere and heated to 850°C for 20 m...

Embodiment 2

[0018] Example 2 Dissolve 152.9g of ammonium metatungstate and 3.34g of scandium nitrate in water respectively, stir well and then mix. Powder was prepared by spray drying, and the powder was calcined and decomposed in a muffle furnace at 600°C for 2 hours. The decomposed product is reduced with hydrogen in a tube furnace. The reduction temperature is slowly heated from room temperature to 600°C, kept for 1 hour, continued to be slowly heated to 950°C, kept for 1 hour, and then slowly cooled. After that, pressing, sintering and impregnation are carried out, and the sintering temperature is 1450°C. Afterwards, the cathode is machined, and the cathode is processed into a cylindrical cathode with a diameter of 2mm and a thickness of 2mm (see figure 1 ). Place the prepared cathode in 2% dilute nitric acid aqueous solution for 15 seconds and wash it with deionized water and absolute ethanol. Afterwards, the cathode was placed in a hydrogen atmosphere and heated to 850°C for 20 m...

Embodiment 3

[0019] Example 3 Dissolve 139.0g of ammonium metatungstate and 33.5g of scandium nitrate in water respectively, stir well and then mix. Powder was prepared by spray drying, and the powder was calcined and decomposed in a muffle furnace at 600°C for 2 hours. The decomposed product was reduced with hydrogen in a tube furnace. The reduction temperature was slowly heated from room temperature to 600°C, kept for 1 hour, continued to be slowly heated to 950°C, kept for 1 hour, and finally cooled slowly. After that, pressing, sintering and impregnation are carried out, and the sintering temperature is 1450°C. Afterwards, the cathode is machined, and the cathode is processed into a cylindrical cathode with a diameter of 2mm and a thickness of 2mm (see figure 1 ). Place the prepared cathode in 2% dilute nitric acid aqueous solution for 15 seconds and wash it with deionized water and absolute ethanol. Afterwards, the cathode was placed in a hydrogen atmosphere and heated to 850°C for...

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Abstract

The invention provides a preparation method of a scandia-doped dispenser cathode material with a turned surface, and belongs to the field of rare-earth refractory metal cathode materials. Cathode matrixes are dipped with a cathode emission active salt, are turned and are subjected to surface cleaning; the cathode matrixes are Sc2O3 and W; the Sc2O3 accounts for 1wt%-10wt% of the total weight of a cathode and the rest is W; and the dipping cathode emission active salt is calcium barium aluminate. The method comprises the following steps: firstly, turning the cathode dipped with the cathode emission active salt into the cathode with the specified dimension, then putting the cathode into an acid solution with the concentration of 0.5wt%-10wt% and keeping the cathode for 10-60 seconds; cleaning the cathode with deionized water and absolute ethyl alcohol respectively; and finally heating the cathode in a hydrogen atmosphere to 830-860 DEG C, carrying out heat preservation for 20-30 minutes and then cooling the cathode. The current density of the cathode subjected to secondary treatment in a pulse voltage test can reach 116A/cm<2> at 950 DEG C.

Description

technical field [0001] The invention belongs to the technical field of rare-earth refractory metal cathode materials, and specifically relates to a method for preparing cathode materials with scandium-containing diffusion surfaces. Background technique [0002] With the continuous development of vacuum electronic devices in the direction of high power and high frequency, higher requirements are put forward for the current density and emission uniformity of the cathode. As the core component, the cathode provides an electron source for the device, so the performance of the cathode directly determines the use characteristics of the device. Scandium-containing diffusion cathodes represent the highest emission level of hot cathodes, and are currently the only hot cathodes that may meet the current density requirements of future high-power microwave devices. [0003] Submicron scandium-containing diffusion cathode, with an average particle size of 600-800nm, is conducive to the ...

Claims

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Application Information

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IPC IPC(8): H01J9/04
CPCH01J9/047
Inventor 王金淑杨韵斐杨帆刘伟周美玲左铁镛
Owner BEIJING UNIV OF TECH
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