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Emission active salt for barium tungsten cathode and preparation thereof

A technology of barium tungsten cathode and active salt, which is applied in the field of emission active salt for barium tungsten cathode and its preparation, which can solve the problem of affecting the distribution of electron cloud in space, the difficulty of high-power magnetron to vibrate and work normally, and the unstable operation of magnetron And other issues

Active Publication Date: 2021-08-20
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the secondary electron emission accounts for about 90% of the anode current during normal operation, if the secondary emission coefficient of the cathode is large enough, it does not need too high thermal emission or the ionization of residual gas molecules is enough to start the device, and the thermal emission of the cathode is too large On the contrary, it will affect the distribution of electron clouds in space, which will cause the magnetron to work unstable.
At present, barium tungsten cathodes and other types of secondary emission materials such as oxide cathodes, rare earth molybdenum metal ceramic cathodes and alloy cathodes used in magnetrons, due to their emission performance, radioactivity, stability and cost, make high-power It is difficult for the magnetron to vibrate and maintain its normal operation

Method used

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  • Emission active salt for barium tungsten cathode and preparation thereof
  • Emission active salt for barium tungsten cathode and preparation thereof
  • Emission active salt for barium tungsten cathode and preparation thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Weigh 88.6g of Ba(NO 3 ) 2 , 20g of Ca(NO 3 ) 2 4H 2 0 and 63.56g of Al(NO 3 ) 3 9H 2 O and other raw materials, the molar ratio of the three is 4:1:2, then weigh 13.27g, the mass fraction is 6% of Y (NO 3 ) 3 ·6H 2 0 was dissolved in 3L of deionized water to form a nitrate solution, and 120g of excess (NH 4 ) 2 CO 3 Dissolve in deionized water as a precipitant. After the precipitation is complete, wash the precipitate with deionized water and ethanol solution, and then place it in an oven at 120°C for drying to form a precursor powder. The morphology of the obtained precursor powder is as follows: figure 1 As shown, put it in a muffle furnace for decomposition at a temperature of 750°C and keep it warm for 3 hours. After being ground, pass through a 200-mesh standard sieve, put it into a high-temperature hydrogen furnace for sintering in a hydrogen environment, set a sintering temperature of 1530°C, keep it for 3 hours, and take it out to obtain aluminate. ...

Embodiment 2

[0036] Weigh 88.6g of Ba(NO 3 ) 2 , 20g of Ca(NO 3 ) 2 4H 2 0 and 63.56g of Al(NO 3 ) 3 9H 2 O and other raw materials, the molar ratio of the three is 4:1:2, then weigh 17.69g, the mass fraction is 8% Y (NO 3 ) 3 ·6H 2 0 was dissolved in 3L of deionized water to form a nitrate solution, and 140g of excess (NH 4 ) 2 CO 3 Dissolve in deionized water as a precipitant. After the precipitation is complete, wash the precipitate with deionized water and ethanol solution, then place it in a 120°C oven for drying to form a precursor powder, and then put it in a muffle furnace for decomposition. The decomposition temperature is 750°C, and the temperature is kept for 3.5 hours. After being ground, pass through a 200-mesh standard sieve, put it into a high-temperature hydrogen furnace for sintering in a hydrogen environment, set the sintering temperature at 1545°C, keep it warm for 4 hours, and take it out to obtain aluminate. Its phase composition is as follows: image 3 show...

Embodiment 3

[0038] Weigh 88.6g of Ba(NO 3 ) 2 , 20g of Ca(NO 3 ) 2 4H 2 0 and 63.56g of Al(NO 3 ) 3 9H 2 O and other raw materials, the molar ratio of the three is 4:1:2, then weigh 22.12g, the mass fraction is 10% of Y (NO 3 ) 3 ·6H 2 0 was dissolved in 3L of deionized water to form a nitrate solution, and 152g of excess (NH 4 ) 2 CO 3 Dissolve in deionized water as a precipitant. After the precipitation is complete, wash the precipitate with deionized water and ethanol solution, then place it in a 120°C oven for drying to form a precursor powder, and then put it in a muffle furnace for decomposition. The decomposition temperature is 750°C and the temperature is kept for 4 hours. After being ground, pass through a 200-mesh standard sieve, put it into a high-temperature hydrogen furnace for sintering in a hydrogen environment, set a sintering temperature of 1555°C, keep it warm for 3.5 hours and take it out to obtain aluminate, whose phase composition is as follows Figure 4 ...

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Abstract

The invention discloses an emission active salt for barium tungsten cathode and its preparation, belonging to the technical field of preparation of hot cathode electron emission materials. With Ba(NO 3 ) 2 , Ca(NO 3 ) 2 4H 2 0. Al(NO 3 ) 3 9H 2 O and Y (NO 3 ) 3 4H 2 O as raw material, with (NH 4 ) 2 CO 3 As a precipitating agent, the precursor powder of the salt is prepared by a liquid-phase co-precipitation method, and the precursor powder is roasted to obtain the final emission active material salt. After the barium tungsten cathode is fully activated, at 1100°C b Under this condition, the pulse emission current density reached 12A / cm 2 above; at 1100°Cb, the secondary emission coefficient is as high as 4. The emission active salt prepared by the method is impregnated into the barium tungsten cathode, and has higher primary electron emission capability and larger secondary emission coefficient. It is expected to be used in magnetron and other fields.

Description

technical field [0001] The invention relates to a novel emission active salt for barium tungsten cathode and a preparation method thereof, in particular to aluminate such as 411 aluminate (n(BaO):n(CaO):n(Al) for barium tungsten cathode 2 o 3 )=4:1:1) to add Y with a mass fraction of 4%-10% 2 o 3 The invention relates to the preparation of a new type of emission active salt, the barium tungsten cathode prepared by the salt has high thermal emission capability and secondary electron emission coefficient, and belongs to the technical field of preparation of electron emission thermal cathode materials. Background technique [0002] Vacuum electronic devices refer to active devices that generate signal amplification and conversion effects through the transmission of electrons or ions between electrodes in a vacuum or gas medium, and are widely used in contemporary national defense equipment, national economy, information systems and people's daily life and play an important r...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01J1/142H01J9/04
CPCH01J1/142H01J9/042H01J9/045
Inventor 王金淑潘兆柳周帆杨韵斐李俊辉吴浩
Owner BEIJING UNIV OF TECH