Y2O3-Lu2O3 system composite rare earth-molybdenum electron emission material and preparation method thereof

An electron emission material, y2o3-lu2o3 technology, is applied in the direction of secondary electron emission electrodes, light-emitting cathode manufacturing, discharge tube main electrode, etc., which can solve the problems of difficult cathode vibration, inconvenient processing, high activation temperature, etc., and achieve improved material The effect of machinability

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

AI Technical Summary

Problems solved by technology

This kind of cathode has high electron emission ability, but there is a problem of high activation temperature
This makes it difficult for the cathode to vibrate when used in a magnetron, which is not convenient for practical application
In addition, the rare earth addition amount of the cathode reaches 30wt%, so that the brittleness of the cathode is improved, which is not convenient for subsequent processing

Method used

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  • Y2O3-Lu2O3 system composite rare earth-molybdenum electron emission material and preparation method thereof
  • Y2O3-Lu2O3 system composite rare earth-molybdenum electron emission material and preparation method thereof
  • Y2O3-Lu2O3 system composite rare earth-molybdenum electron emission material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Dissolve 48.4934 grams of yttrium nitrate and 10.4301 grams of lutetium nitrate in absolute ethanol respectively, filter the solution after completely dissolving, weigh 120.0235 grams of molybdenum trioxide powder and mix it with the filtered nitrate solution, and place them in a water bath at 80°C Heat over medium heat, stirring constantly, until the liquid evaporates completely.

[0023] (2) Decompose the powder obtained after evaporation at 500° C. under an air atmosphere until the nitrate is completely decomposed, and the N element in the powder is completely removed.

[0024] (3) Crushing and sieving the powder, and then reducing the powder under a hydrogen atmosphere. The reduction is carried out in two steps. First, hold at 500°C for 2 hours, then raise the temperature to 900°C for 2 hours, and then cool with the furnace. The reduced powder is pressed and sintered to make a rare earth-molybdenum secondary electron emission material green body. The embryo bo...

Embodiment 2

[0026] (1) Dissolve 48.4934 grams of yttrium nitrate and 10.4301 grams of lutetium nitrate in absolute ethanol respectively, and filter the solution after completely dissolving. Weigh 120.0235 g of molybdenum trioxide powder and mix it with the filtered nitrate solution, and heat it in a water bath at 90°C, stirring continuously until the liquid evaporates completely.

[0027] (2) Decompose the powder obtained after evaporation at 550° C. under an air atmosphere until the nitrate is completely decomposed, and the N element in the powder is completely removed.

[0028] (3) Crushing and sieving the powder, and then reducing the powder under a hydrogen atmosphere. The reduction is carried out in two steps. First, hold at 550°C for 4 hours, then increase the temperature to 950°C for 4 hours, and then cool with the furnace. The reduced powder is pressed and sintered to make a rare earth-molybdenum secondary electron emission material green body. The embryo body is machined into a...

Embodiment 3

[0030] (1) Dissolve 32.3289 grams of yttrium nitrate and 20.8602 grams of lutetium nitrate in absolute ethanol respectively, and filter the solution after completely dissolving. Weigh 120.0235 g of molybdenum trioxide powder and mix it with the filtered nitrate solution, and heat it in a water bath at 100°C, stirring continuously until the liquid evaporates completely.

[0031] (2) Decompose the powder obtained after evaporation at 520° C. under an air atmosphere until the nitrate is completely decomposed, and the N element in the powder is completely removed.

[0032](3) Crushing and sieving the powder, and then reducing the powder under a hydrogen atmosphere. The reduction is carried out in two steps. First, hold at 520°C for 3 hours, then increase the temperature to 920°C for 3 hours, and then cool with the furnace. The reduced powder is pressed and sintered to make a rare earth-molybdenum secondary electron emission material green body. The embryo body is machined into a...

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Abstract

The invention discloses Y2O3-Lu2O3 system composite rare earth-molybdenum electron emission material and a preparation method thereof, and belongs to the technical field of rare earth refractory metal cathode materials. The prior cathode material cannot satisfy the higher electron emission requirements. The Y2O3-Lu2O3 system composite rare earth-molybdenum electron emission material and the preparation method thereof are characterized in that yttrium and lutetium which are rare earth elements are used as additional elements, and are mixed into metal molybdenum in any proportion for the preparation of the cathode material. The material is obtained by mixing Lu2O3 and Y2O3 which are two rare earth oxides in any proportion, the mixed rare earth oxides account for 20 percent wt of the gross weight of the emission material, and others are molybdenum. The Y2O3-Lu2O3 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, and optimum activation temperature is less than the lanthanum-containing cathode and a cerium-containing cathode.

Description

technical field [0001] Y 2 o 3 -Lu 2 o 3 The system composite rare earth-molybdenum electron emission material and its preparation belong to the technical field of rare earth refractory metal cathode materials. Background technique [0002] In high-power electron tubes and magnetrons, thoriated tungsten (W-ThO 2 ) cathode as the emission source. The working temperature of thoriated tungsten cathode is as high as 1800°C, and it is brittle and difficult to process. Since thorium is a radioactive element with a long half-life, thoriated tungsten cathodes seriously threaten human health and the living environment during processing, production, and recycling of waste products. Many problems show that thoriated tungsten cathode is not an ideal cathode material today, and its substitute products must be developed. Previously, the thermal emission and secondary emission properties of lanthanum-containing rare earth-molybdenum cathodes have been developed [1, 2], and they have...

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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