Simple preparation method of aluminate electron-emission substance for hot cathode

A technology of electron emission and aluminate, which is applied in the preparation of alkaline earth metal aluminate/alumina/hydroxide, parts of discharge tube/lamp, circuits, etc., can solve the problem of large aluminate particle size and inconsistent phase Single, multi-emission performance and other issues, to achieve the effect of single phase, simple preparation process, and good emission performance

Active Publication Date: 2018-08-14
BEIJING UNIV OF TECH
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  • Abstract
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  • Claims
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Problems solved by technology

[0003] Aiming at the disadvantages of the traditional mechanical mixing method and co-precipitation method that the aluminate finally prepared has a larger particle size, more and more phases, and lower emission performance, the present invention adopts a sol-gel method and uses Ba(NO 3 ) 2 , Ca(NO 3 ) 2 4H 2 0 and Al(NO 3 ) 3 9H 2 O as the raw material, EDTA as the complexing agent, the precursor powder of the salt was prepared by the sol-gel method, and the precursor powder was roasted to obtain the final aluminate

Method used

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  • Simple preparation method of aluminate electron-emission substance for hot cathode
  • Simple preparation method of aluminate electron-emission substance for hot cathode
  • Simple preparation method of aluminate electron-emission substance for hot cathode

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Effect test

Embodiment 1

[0027] Weigh 52.3g of Ba(NO 3 ) 2 , 11.8g of Ca(NO 3 ) 2 4H 2 0 and 37.5g of Al(NO 3 ) 3 9H 2 O and other raw materials, the molar ratio of which is 4:1:2, was dissolved in 2L of deionized water to form a nitrate solution, and 102.3g of EDTA was weighed and dissolved in 100ml of ammonia water. Put the nitrate solution in a water bath and heat it up to 80°C. At the same time, slowly add the EDTA solution into it, heat and stir continuously to form a sol, place it in an oven at 120°C to remove water to form a xerogel, and then put it in a horse Decompose in a Furnace, the decomposition temperature is 800°C, and keep warm for 4h. The morphology of the obtained precursor powder is as follows figure 1 As shown, after being ground, it is passed through a 200-mesh standard sieve, and then it is put into a high-temperature hydrogen furnace for sintering in a hydrogen environment. The sintering temperature is set at 1400°C, and the aluminate is obtained after holding for 4 hour...

Embodiment 2

[0029] Weigh 52.3g of Ba(NO 3 ) 2 , 11.8g of Ca(NO 3 ) 2 4H 2 0 and 37.5g of Al(NO 3 ) 3 9H 2O and other raw materials, the molar ratio of which is 4:1:2, was dissolved in 2L of deionized water to form a nitrate solution, and 102.3g of EDTA was weighed and dissolved in 100ml of ammonia water. Put the nitrate solution in a water bath and heat it up to 80°C. At the same time, slowly add the EDTA solution into it, heat and stir continuously to form a sol, place it in an oven at 120°C to remove water to form a xerogel, and then put it in a horse Decompose in a Furnace, the decomposition temperature is 800°C, and keep warm for 4h. The obtained precursor powder was ground and passed through a 200-mesh standard sieve, and then put into a high-temperature hydrogen furnace for sintering in a hydrogen environment. The sintering temperature was set at 1500°C, and after holding for 4 hours, the aluminate was obtained. The phase analysis was as follows: Figure 4 shown. Cathode im...

Embodiment 3

[0031] Weigh 52.3g of Ba(NO 3 ) 2 , 7.9g of Ca(NO 3 ) 2 4H 2 0 and 50.0g of Al(NO 3 ) 3 9H 2 O and other raw materials, the molar ratio of which is 6:1:4, was dissolved in 2L of deionized water to form a nitrate solution, and 102.3g of EDTA was weighed and dissolved in 100ml of ammonia water. Put the nitrate solution in a water bath and heat it up to 80°C. At the same time, slowly add the EDTA solution into it, heat and stir continuously to form a sol, place it in an oven at 120°C to remove water to form a xerogel, and then put it in a horse Decompose in a Furnace, the decomposition temperature is 800°C, and keep warm for 4h. The obtained precursor powder was ground and passed through a 200-mesh standard sieve, and then put into a high-temperature hydrogen furnace for sintering in a hydrogen environment. The sintering temperature was set at 1400°C. After holding for 4 hours, the aluminate was obtained. Its microscopic appearance is as follows: image 3 shown. Cathode ...

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Abstract

The invention discloses a simple preparation method of an aluminate electron-emission substance for a hot cathode, and belongs to the technical field of preparation of the electron-emission materialsfor the hot cathodes. The preparation method comprises the following steps: taking Ba(NO3)2, Ca(NO3)2.4H2O and Al(NO3)3.9H2O as raw materials and taking EDTA (Ethylene Diamine Tetraacetic Acid) as a complexing agent to prepare precursor powder of salt by a sol-gel method; roasting the precursor powder to obtain final aluminate, wherein after the cathode is fully activated, the pulse emission current density under 950 DEG C b can reach 100A/cm<2> or above and emission slope reaches 1.4 or above. The aluminate prepared by the method has the advantages of simple preparation process, uniform components, single phase, low melting point, good emission performance and the like and is expected to be used in the fields such as microwave vacuum electronic devices.

Description

technical field [0001] The invention relates to a simple preparation method of an aluminate electron emission material for a hot cathode, in particular to a preparation method of an aluminate with excellent primary electron emission performance by using EDTA as a complexing agent, adopting sol-gel and roasting The invention belongs to the technical field of preparation of primary electron emission thermal cathode materials. Background technique [0002] Vacuum electronic devices play an important role in national economic fields such as radio, television, radio communication, space navigation, electronic countermeasures, and modern industrial induction heating. As the electron source of vacuum electronic devices, the cathode directly determines the characteristics and service life of vacuum electronic devices. At present, hot cathode materials are often used in vacuum electronic devices, but there is a certain gap in the emission performance of cathodes prepared in my count...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/16H01J1/142
CPCC01F7/16C01P2002/72C01P2004/03H01J1/142
Inventor 王金淑潘兆柳刘伟周帆杨韵斐李俊辉吴浩
Owner BEIJING UNIV OF TECH
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