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High-current density electronic emission body rareearth-Sc-W based material and mfg. method thereof

An electron emitter and high current density technology, applied in the directions of discharge tube solid thermionic cathode, discharge tube main electrode, discharge tube cold cathode, etc., can solve problems such as uneven emission, affecting the improvement of cathode life, and difficulty in replenishment, etc. Achieve the effect of improving high temperature resistance, improving uniformity and good repeatability

Inactive Publication Date: 2003-03-12
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] (1) The added rare earth element Sc or its oxide is unevenly distributed, resulting in uneven emission and the appearance of abnormal Schottky effect
[0005] (2) The diffusion performance of rare earth elements Sc and its oxides is poor, making it difficult to replenish, and the performance of high temperature resistance and ion bombardment resistance is not good, which affects the improvement of cathode life.
[0006] (3) The process repeatability is not good
The research content that the present invention carries out has not yet seen domestic and foreign reports

Method used

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  • High-current density electronic emission body rareearth-Sc-W based material and mfg. method thereof
  • High-current density electronic emission body rareearth-Sc-W based material and mfg. method thereof
  • High-current density electronic emission body rareearth-Sc-W based material and mfg. method thereof

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0020] Example 1, 10.05 grams of scandium nitrate was dissolved in water, and added to 120.64 grams of powdered blue tungsten (wherein scandium oxide accounted for 3% of the total weight of the final product rare earth scandium tungsten-based high current density electron emitter material), in a multi-stage hydrogen furnace In the process, reduce at 650°C for 1 hour, and reduce at 900°C for 2 hours to obtain tungsten powder doped with scandium oxide; press the above-mentioned tungsten powder doped with scandium oxide on a hydraulic press to form a thin slice sample of Φ3.5×1mm, and the pressing pressure is 350Mpa / cm 2 , in a tungsten wire mesh furnace, sintering in a hydrogen atmosphere at 1750 ° C to prepare a rare earth scandium tungsten sintered body. The above-mentioned sintered body is impregnated with aluminate, ultrasonically cleaned and annealed, and then laser-welded with a molybdenum sleeve to produce an electron emitter material.

example 2

[0021] Example 2, 10.05 grams of scandium nitrate and 1.441 grams of ammonium rhenate were dissolved in water respectively and added to 119.39 grams of powdered blue tungsten (wherein scandium oxide accounts for the total weight of the final product rare earth scandium tungsten-based high current density electron emitter material 3%, rhenium accounted for 1%), in a multi-stage hydrogen furnace, 500 ° C reduction for 1 hour, 800 ° C reduction for 3 hours, to obtain powder doped with scandium oxide and rhenium; press the above tungsten powder on a hydraulic press to Φ3. 5×1mm thin slice sample, the pressing pressure is 350Mpa / cm 2 , in a tungsten wire mesh furnace, sintering in a hydrogen atmosphere at 1400 ° C to prepare a rare earth scandium tungsten sintered body. The above-mentioned sintered body is impregnated with aluminate, ultrasonically cleaned and annealed, and then laser-welded with a molybdenum sleeve to produce an electron emitter material.

example 3

[0022] Example 3, 33.50 grams of scandium nitrate and 4.323 grams of ammonium rhenate were dissolved in water respectively and added to 108.20 grams of powdered blue tungsten (wherein scandium oxide accounts for the total weight of the final product rare earth scandium tungsten-based high current density electron emitter material 10% of rhenium, rhenium accounted for 3%), in a multi-stage hydrogen furnace, 650 ℃ reduction for 1.5 hours, 900 ℃ reduction for 2 hours, get doped scandium oxide and rhenium, the tungsten powder is pressed on the hydraulic press to Φ3.5 For a thin sheet sample of ×1mm, the pressing pressure is 350Mpa / cm 2 , in a tungsten wire mesh furnace, sintering in a hydrogen atmosphere at 1400 ° C to prepare a rare earth scandium tungsten sintered body. The above-mentioned sintered body is impregnated with aluminate, ultrasonically cleaned and annealed, and then laser-welded with a molybdenum sleeve to produce an electron emitter material.

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Abstract

A ScW-base rare-earth material as high-current-density electronic emitter (cathode) contains scandium oxide, rhenium and tungsten. It is prepared through proportionally mixing blue tungsten with aqueous solution of scandium nitrate, adding the aqueous solution of ammonium rhenate, reduction reaction in hydrogen at 500-650 deg.C for 0.5-1.5 hr, maintaing 800-1000 deg.c for 1-3 hr, powder metallurgy, dipping in solution of aluminate, ultrasonic washing at annealing. Its advantages are high emission uniformity and high resistance to high temp and ion bombardment.

Description

1. Technical field [0001] A rare-earth scandium-tungsten-based high-current-density electron emitter material and a preparation method thereof belong to the technical field of rare-earth refractory metal cathode materials. 2. Background technology [0002] Electron emitters are the heart of vacuum electronic devices. Vacuum display devices and microwave devices play a pivotal role in the information industry and military engineering. Vacuum display devices including kinescopes and display tubes have developed rapidly in recent years. With the development of such devices to large screens and high-definition, the requirements for the emission current density and lifetime of the electron emitters used in them are getting higher and higher, from the early 0.5A / cm 2 To 2A / cm 2 , 4A / cm 2 and even higher current densities. The traditional oxide cathode can not meet this requirement at all, and the new oxide cathode developed in recent years is at 2A / cm 2 The above application...

Claims

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Application Information

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IPC IPC(8): C22C27/04H01J1/14H01J1/30
Inventor 王金淑周美玲王亦曼陶斯武
Owner BEIJING UNIV OF TECH
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