Preparation method of aluminate electron emission material for impregnated cathode

An electron emission material, aluminate technology, applied in the preparation of alkaline earth metal aluminate/alumina/aluminum hydroxide, circuits, electrical components, etc., can solve the problem that the chemical composition of aluminate cannot be designed to keep the composition consistent, and synthesize aluminum Solve the problems that the consistency of salt composition and performance cannot be guaranteed, and achieve the effects of precise control of chemical composition, small particle size, and reasonable process design

Active Publication Date: 2020-10-09
NANJING TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Since commercially available nitrates contain trace impurities, adsorbed water, and crystallized water, it is almost impossible to obtain a mixed salt solution for coprecipitation reaction with precise control of the proportion of each element component by direct weighing, which will inevitably lead to the synthesis of aluminate The chemical composition cannot be consistent with the design composition; moreover, when the batch of raw materials or the manufacturer is replaced, the consistency of the composition and performance of the synthetic aluminate cannot be guaranteed; in addition, the co-precipitated product will produce Changes in composition of aluminates due to partial dissolution

Method used

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  • Preparation method of aluminate electron emission material for impregnated cathode
  • Preparation method of aluminate electron emission material for impregnated cathode
  • Preparation method of aluminate electron emission material for impregnated cathode

Examples

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Embodiment 1

[0025] The chemically pure barium nitrate and deionized water purchased from Xilong Chemical Co., Ltd. were prepared into a barium nitrate solution with a mass concentration of 4%. After weighing a certain weight, pour it into a 255.15-gram calcined at 1300°C to constant weight Crucible (alumina content is 99.3%), weigh the solution and the accurate mass of the crucible is 411.15 grams, first put the crucible in an oven at 100°C for 24 hours, then place it in an electric furnace and calcinate at 200°C to constant weight, weigh and calcinate The exact weight of the product, together with the crucible, was 261.39 grams, resulting in a weight of 6.24 grams of calcined barium nitrate. The chemically pure calcium nitrate purchased from Xilong Chemical Co., Ltd. and deionized water were prepared into a calcium nitrate solution with a mass concentration of 20%. After weighing a certain weight, pour it into a calcined at 1300°C to a constant weight, weighing 263.02 grams. Crucible (al...

Embodiment 2

[0032] The chemically pure barium nitrate and deionized water purchased from Sinopharm Group Chemical Reagent Co., Ltd. were prepared into a barium nitrate solution with a mass concentration of 12%. After a certain weight was weighed, it was poured into a 269.39 g barium nitrate solution calcined at 1400°C to a constant weight. Crucible (alumina content is 99.5%), weigh the solution and the accurate mass of the crucible is 421.45 grams, first place the crucible in an oven at 150°C for 12 hours, then place it in an electric furnace and calcinate at 500°C until constant weight, weigh the calcined The exact weight of the product, together with the crucible, was 287.64 grams, resulting in a weight of 18.25 grams of calcined barium nitrate. The chemically pure calcium nitrate purchased from Sinopharm Group Chemical Reagent Co., Ltd. and deionized water were prepared into a calcium nitrate solution with a mass concentration of 45%. After a certain weight was weighed, it was poured in...

Embodiment 3

[0039] The chemically pure barium nitrate purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. and deionized water were prepared into a barium nitrate solution with a mass concentration of 8%, weighed a certain weight, poured it into calcination at 1400°C to constant weight, and the weight was 258.35 gram of crucible (aluminum oxide content is 99.7%), weigh the solution and the accurate mass of the crucible is 410.28 grams, first put the crucible in a 120°C oven and bake it for 18 hours, then place it in an electric furnace and calcinate it to constant weight at 400°C, weigh Measure the calcined product together with the accurate weight of the crucible of 270.50 grams to obtain a weight of 12.15 grams of calcined barium nitrate. The chemically pure calcium nitrate purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. and deionized water were prepared into a calcium nitrate solution with a mass concentration of 30%. Weighed a certain weight and poured it i...

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Abstract

A method for preparing an aluminate electron emission material used for an impregnated type negative electrode is provided. The method includes (1) accurately weighing barium nitrate, calcium nitrateand aluminum nitrate solutions, drying, calcining, and then accurately weighing the mass of the calcined barium nitrate, calcium oxide and alumina; (2) accurately measuring purity of the calcined barium nitrate, the calcium oxide and the alumina; (3) calculating the mass of pure barium nitrate obtained by drying and calcining 100 g of the barium nitrate solution, the mass of pure calcium oxide obtained by drying and calcining 100 g of the calcium nitrate solution, and the mass of pure alumina obtained by drying and calcining 100 g of the aluminum nitrate solution; (4) calculating the weights of needed barium nitrate, calcium nitrate and aluminum nitrate solutions according to the chemical constitution and the weight of an aluminate to be prepared; (5) weighing the barium nitrate, calcium nitrate and aluminum nitrate solutions according to the calculation result, and mixing the weighed solutions to obtain a mixed salt solution for coprecipitation synthesis of the aluminate electron emission material; and (6) preparing the aluminate electron emission material by adopting a process combining coprecipitation and spray pyrolysis. The method is reasonable in process and design, and simple to operate, and the prepared aluminate has an accurately controlled chemical constitution and a good degree of crystallinity.

Description

technical field [0001] The invention belongs to the field of microwave electric vacuum device manufacture, and in particular relates to a method for preparing an impregnated cathode aluminate electron emission material. Background technique [0002] The cathode is the "heart" of microwave vacuum electronic devices, and plays a vital role in the power output and life of high-power microwave devices. The impregnated barium tungsten cathode is composed of a porous tungsten matrix and an aluminate electron emission material impregnated in it. It has the characteristics of high emission current density and excellent anti-poisoning performance. It is used in medium and high-power microwave electric vacuum electronic devices. most widely. The performance of the impregnated barium tungsten cathode mainly depends on the chemical composition of the aluminate electron emission material and the uniformity of the composition distribution of each element. Researchers found that the use ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/16H01J1/142
CPCC01F7/16C01P2002/72H01J1/142
Inventor 魏建君李婧琳冯永宝
Owner NANJING TECH UNIV
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