Y2O3-Gd2O3 system composite rare earth-molybdenum electron emission material and preparation method thereof

An electron emission material, y2o3-gd2o3 technology, applied in the direction of secondary electron emission electrode, light-emitting cathode manufacturing, discharge tube main electrode, etc., can solve problems such as poor electron emission performance, and achieve the effect of stable performance

Inactive Publication Date: 2009-06-03
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, its secondary electron emission performance decays rapidly with the increase of voltage, that is, when the working voltage is high, its electron emission performance is poor.

Method used

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  • Y2O3-Gd2O3 system composite rare earth-molybdenum electron emission material and preparation method thereof
  • Y2O3-Gd2O3 system composite rare earth-molybdenum electron emission material and preparation method thereof
  • Y2O3-Gd2O3 system composite rare earth-molybdenum electron emission material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] (1) Add 64.6634 grams of Y(NO 3 ) 3 , 22.9140 grams of Gd(NO 3 ) 3 Respectively dissolve in absolute ethanol, and filter the solution after it is completely dissolved. Weigh 120.0235 grams of molybdenum trioxide powder and mix with the filtered nitrate solution, and heat it in a water bath at 80°C, stirring continuously until the liquid is completely evaporated.

[0024] (2) The powder obtained after evaporation is decomposed at 500°C in an air atmosphere until the nitrate is completely decomposed, and the N element in the powder is completely removed.

[0025] (3) The powder is crushed, sieved, and then the powder is reduced in a hydrogen atmosphere. The reduction is carried out in two steps. First, it is kept at 500°C for 2 hours, and then the temperature is raised to 900°C for 2 hours, and then cooled in the furnace. The reduced powder is pressed and sintered into a rare earth-molybdenum secondary electron emission material embryo. The embryo body is machined into rare e...

Embodiment 2

[0027] (1) Add 24.2488 grams of Y(NO 3 ) 3 , 51.5565 grams of Gd(NO 3 ) 3 Respectively dissolve in absolute ethanol, and filter the solution after it is completely dissolved. Weigh 120.0235 grams of molybdenum trioxide powder and mix with the filtered nitrate solution, and heat it in a water bath at 100°C, stirring continuously until the liquid is completely evaporated.

[0028] (2) Decompose the powder obtained after evaporation at 550°C in an air atmosphere until the nitrate is completely decomposed, and the N element in the powder is completely removed.

[0029] (3) The powder is crushed, sieved, and then the powder is reduced in a hydrogen atmosphere. The reduction is carried out in two steps. First, it is kept at 500°C for 4 hours, then the temperature is raised to 900°C for 4 hours, and then it is cooled in the furnace. The reduced powder is pressed and sintered into a rare earth-molybdenum secondary electron emission material embryo. The embryo body is machined into a rare ...

Embodiment 3

[0031] (1) Add 32.3318 grams of Y(NO 3 ) 3 , 45.8280 grams of Gd(NO 3) 3 Respectively dissolve in absolute ethanol, filter the solution after it is completely dissolved. Weigh 120.0235 grams of molybdenum trioxide powder and mix with the filtered nitrate solution, and heat it in a water bath at 90°C, stirring continuously until the liquid is completely evaporated.

[0032] (2) The powder obtained after evaporation is decomposed at 550°C in an air atmosphere until the nitrate is completely decomposed, and the N element in the powder is completely removed.

[0033] (3) The powder is crushed, sieved, and then the powder is reduced in a hydrogen atmosphere. The reduction is carried out in two steps. First, it is kept at 550°C for 3 hours, and then the temperature is raised to 900°C for 3 hours, and then cooled in the furnace. The reduced powder is pressed and sintered into a rare earth-molybdenum secondary electron emission material embryo. The embryo body is machined into rare earth ...

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Abstract

The invention discloses Y2O3-Gd2O3 system composite rare earth-molybdenum electron emission material and a preparation method thereof, and belongs to the technical field of secondary electron emission materials. The prior secondary electron emission material cannot satisfy the higher electron emission requirements. The Y2O3-Gd2O3 system composite rare earth-molybdenum electron emission material and the preparation method thereof are characterized in that yttrium and gadolinium which are rare earth elements are used as additional elements, and are mixed into metal molybdenum in different proportions for the preparation of the cathode material. The Y2O3-Gd2O3 system composite rare earth-molybdenum electron emission material is obtained by mixing Gd2O3 and Y2O3 which are two rare earth oxides in any proportion, the mixed rare earth oxides account for 30 percent wt of the gross weight of the emission material, and others are molybdenum. The Y2O3-Gd2O3 system composite rare earth-molybdenum electron emission material can be utilized to make rare earth-molybdenum secondary electron emission material, the secondary electron emission coefficient thereof is higher a lanthanum-containing cathode, optimum activation temperature is less than the lanthanum-containing cathode, and the emission performance is stable in a larger voltage range and is superior to a cerium-containing cathode.

Description

Technical field [0001] Y 2 O 3 -Gd 2 O 3 The system composite rare earth-molybdenum electron emission material and its preparation belong to the technical field of secondary electron emission materials. Background technique [0002] In high-power electron tubes and magnetrons, thorium tungsten (W-ThO 2 ) The cathode is used as the emission source. The working temperature of thorium tungsten cathode is as high as 1800℃, which is brittle and difficult to process. Because thorium is a radioactive element with a long half-life, thorium tungsten cathodes seriously threaten human health and the living environment during processing, production, and recycling of waste products. Many problems show that thorium tungsten cathode is not an ideal cathode material today, and its replacement products must be developed. People have previously developed the secondary emission properties of lanthanum-containing rare earth-molybdenum cathodes [1, 2] and have been applied in some tube types. However...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01J1/32H01J9/12
Inventor 王金淑刘伟高非任志远周美玲左铁镛
Owner BEIJING UNIV OF TECH
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