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Press type barium-tungsten cathode containing yttrium and preparation method thereof

A barium tungsten cathode and cathode technology, which is applied in the field of rare earth refractory metal cathode materials, can solve the problem that the secondary electron emission performance is difficult to meet the use requirements of high-power magnetrons, the thermal emission performance is poor, and the magnetron vibration starting ability is poor. question

Inactive Publication Date: 2011-09-07
BEIJING UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the secondary electron emission performance of barium tungsten cathode materials widely used in magnetrons cannot meet the requirements of high-power magnetrons.
The recently developed composite rare earth molybdenum cermet cathode material has stable secondary electron emission performance and strong electron bombardment resistance, but its thermal emission performance is poor, resulting in poor magnetron vibration.

Method used

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  • Press type barium-tungsten cathode containing yttrium and preparation method thereof
  • Press type barium-tungsten cathode containing yttrium and preparation method thereof

Examples

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Effect test

Embodiment 1

[0013] Example 1 Dissolve 40.70812 grams of yttrium nitrate, 92.05934 grams of ammonium metatungstate, 9.587834 grams of barium nitrate, 3.907167 grams of aluminum nitrate, 1.504999 grams of calcium nitrate, and 100 grams of citric acid in water respectively, and then add nitric acid in the ammonium metatungstate aqueous solution Yttrium aqueous solution, barium nitrate aqueous solution, aluminum nitrate aqueous solution and calcium nitrate solution, and finally citric acid solution was added, and the mixed solution was heated in a water bath at 80°C for 4 hours to form a sol, and the colloid was dried at 150°C for 3 hours to form a gel. Decompose in air atmosphere at 550°C for 3h to form oxide powder. Subsequently, two steps of reduction were carried out under hydrogen atmosphere, the first reduction temperature was 550°C, the holding time was 2h, the second step reduction temperature was 850°C, and the holding time was 2h. The reduced powder is compressed at a pressure of 4t...

Embodiment 2

[0014] Example 2 Dissolve 33.92343 grams of yttrium nitrate, 94.58151 grams of ammonium metatungstate, 9.587834 grams of barium nitrate, 3.907167 grams of aluminum nitrate, 1.504999 grams of calcium nitrate, and 100 grams of citric acid in water respectively, and then add nitric acid in the ammonium metatungstate aqueous solution Yttrium aqueous solution, barium nitrate aqueous solution, aluminum nitrate aqueous solution and calcium nitrate solution, and finally citric acid solution was added, and the mixed solution was heated in a water bath at 60°C for 6 hours to form a sol, and the colloid was dried at 100°C for 5 hours to form a gel. Decompose in the air atmosphere at 500°C for 4h to form oxide powder. Subsequently, two steps of reduction were carried out under hydrogen atmosphere, the first reduction temperature was 500°C, the holding time was 2h, and the second step reduction temperature was 750°C, and the holding time was 1h. The reduced powder is compressed at a pressu...

Embodiment 3

[0015] Example 3 Dissolve 50.88515 grams of yttrium nitrate, 88.27608 grams of ammonium metatungstate, 9.587834 grams of barium nitrate, 3.907167 grams of aluminum nitrate, 1.504999 grams of calcium nitrate, and 100 grams of citric acid in water respectively, and then add nitric acid in the ammonium metatungstate aqueous solution Yttrium aqueous solution, barium nitrate aqueous solution, aluminum nitrate aqueous solution and calcium nitrate solution, and finally citric acid solution was added, and the mixed solution was heated in a water bath at 80°C for 4 hours to form a sol, and the colloid was dried at 120°C for 4 hours to form a gel. Decompose in the air atmosphere at 550°C for 5h to form oxide powder. Then two steps of reduction were carried out under hydrogen atmosphere, the first reduction temperature was 550°C, the holding time was 3h, the second step reduction temperature was 800°C, and the holding time was 2h. The reduced powder is compressed at a pressure of 2t / cm ...

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Abstract

The present invention relates to a press type barium-tungsten cathode containing yttrium and a preparation method thereof, belonging to the field of rare-earth refractory metal cathode materials and aiming to solve the problem that the existing cathode materials cannot meet the use requirement of a high-power permatron. The cathode contains the following components in percentage by weight: 10-20 percent of rare-earth oxide Y2O3, 5-15 percent of BaO, 5-15 percent of CaO and 5-15 percent of Al2O3, wherein the molar ratio of Ba to Ca to Al is 4:1:1, and the balance is tungsten. The preparation method comprises the following steps: using ammonium meta-tungstate, yttrium nitrate and ternary nitrates as raw materials and citric acid as a complexing agent; preparing compound gel by a sol-gel method; reducing in hydrogen atmosphere by the following two steps: (1) preserving heat for 2-4 hours at 500-550 DEG C; (2) preserving heat for 1-2 hours at 750-950 DEG C; pressing powder obtained after the reducing under the pressure of 1-4t / cm<2> with sintering temperature of 1,400-1,650 DEG C; and sintering the pressed powder to process the cathode under the condition of preserving heat for 1-5 minutes. Proved by testing, the secondary emission coefficient of the press type cathode is obviously higher than the secondary emission coefficient of a barium-tungsten cathode, and the heat emission current density of the cathode can reach 14.54A / cm<2>.

Description

technical field [0001] A compressed barium tungsten cathode containing yttrium and a preparation method thereof belong to the technical field of rare earth refractory metal cathode materials. Background technique [0002] Magnetron is one of the most widely used electric vacuum devices at present. It has the advantages of high efficiency, high output power per unit weight, simple structure, high reliability and low price. It is widely used in radar, navigation, guidance and electronic countermeasures And various civilian fields, the performance of the magnetron is largely determined by the emission performance of the cathode, which requires the cathode to have excellent secondary electron emission performance and certain thermal electron emission performance. [0003] However, with the continuous development of technologies such as radar, aerospace, electronic countermeasures, and microwave heating, the output power of the magnetron has been further increased, so higher requ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01J23/04H01J9/12
Inventor 王金淑刘伟杨帆任志远崔云涛李莉莉赵雷张喜珠周美玲左铁镛
Owner BEIJING UNIV OF TECH