Preparation method for compacting scandium containing dispenser cathode

Abstract

The invention relates to a method for producing compression scandium disperse cathode, wherein said method dissolves the Sc (NO3)3, Ba (NO3)2, Ca (NO3)2, Al (NO3)3 and ammonium metatungstate into water to be mixed, and adds citrate solution to be bathed, to form gel, then drying it to form gel, to be decomposed to obtain powder; reducing and compressing the powder into sample; sintering it under hydrogen gas to form cathode material. The invention has better repeat property, to apply batch production. And the elements of cathode material are uniformly distributed, with better emission property under 800Deg. C.

Description

technical field

[0001] The invention discloses a method for preparing a compressed scandium-containing diffusion cathode, which belongs to the technical field of rare earth refractory metal cathode materials. Background technique

[0002] At present, the diffused thermionic emission cathode (barium tungsten cathode) based on alkaline earth metal Ba is mainly used in various types of military and civilian microwave vacuum electronic devices widely used at home and abroad. The active material is mainly composed of calcium aluminate with different molar ratios. Composition of barium salts. With the continuous improvement of the power and frequency of microwave tubes, barium tungsten cathodes have been difficult to meet the requirements of devices for cathode current density, and scandium-containing diffusion cathodes (adding Sc elements to barium tungsten cathodes) have become the most ideal due to their low temperature and large emission characteristics. It is the most import...

Examples

example 1

[0025] Example 1. Dissolve 2.1966 grams of scandium nitrate, 12.3093 grams of ammonium metatungstate, 0.6777 grams of barium nitrate, 0.1531 grams of calcium nitrate, 0.4864 grams of aluminum nitrate, and 10 grams of citric acid in water. First, dissolve scandium nitrate, barium nitrate, and aluminum nitrate Mix with calcium nitrate solution, then add ammonium metatungstate solution, and finally add citric acid solution. The mixed solution was placed in a water bath at 80°C until a sol was formed. It was then dried at 80°C to form a gel. After decomposing the gel at 500°C for 5 hours under atmospheric atmosphere, a yellow powder was obtained. The decomposed powder is subjected to two-step reduction in a hydrogen atmosphere, the first reduction temperature is 500°C, the holding time is 2 hours, the second step reduction temperature is 900°C, and the holding time is 2 hours. Then the powder at 2.5t / cm 3 Press under pressure to form a round cake of Φ3×1.2mm, and then sinter at...

example 2

[0026] Example 2. Dissolve 2.1966 grams of scandium nitrate, 11.6255 grams of ammonium metatungstate, 1.3554 grams of barium nitrate, 0.3062 grams of calcium nitrate, 0.9728 grams of aluminum nitrate, and 10 grams of citric acid in water. First, dissolve scandium nitrate, barium nitrate, and aluminum nitrate Mix with calcium nitrate solution, then add ammonium metatungstate solution, and finally add citric acid solution. The mixed solution was placed in a water bath at 100°C until a sol was formed. It was then dried at 100°C to form a gel. The gel was decomposed at 550°C under an oxygen atmosphere for 5 hours to obtain a yellow powder. The decomposed powder is subjected to two-step reduction in a hydrogen atmosphere, the first reduction temperature is 500°C, the holding time is 2 hours, the second step reduction temperature is 1000°C, and the holding time is 2 hours. Then put the powder at 2t / cm 3 Pressed under pressure to form a round cake of Φ5×1.2mm, and then sintered at...

example 3

[0027] Example 3. Dissolve 2.1966 grams of scandium nitrate, 11.6255 grams of ammonium metatungstate, 1.3554 grams of barium nitrate, 0.3062 grams of calcium nitrate, 0.9728 grams of aluminum nitrate, and 10 grams of citric acid in water. First, dissolve scandium nitrate, barium nitrate, and aluminum nitrate Mix with calcium nitrate solution, then add ammonium metatungstate solution, and finally add citric acid solution. The mixed solution was placed in a water bath at 90°C until a sol was formed. It was then dried at 120°C to form a gel. After decomposing the gel at 550°C for 5 hours under atmospheric atmosphere, a yellow powder was obtained. The decomposed powder is subjected to two-step reduction in a hydrogen atmosphere, the first reduction temperature is 500°C, the holding time is 2 hours, the second step reduction temperature is 850°C, and the holding time is 2 hours. Then put the powder at 1.5t / cm 3 Pressed under pressure to form a round cake of Φ3×1.2mm, and then si...

technical field

[0001] The invention discloses a method for preparing a compressed scandium-containing diffusion cathode, which belongs to the technical field of rare earth refractory metal cathode materials. Background technique

[0002] At present, the diffused thermionic emission cathode (barium tungsten cathode) based on alkaline earth metal Ba is mainly used in various types of military and civilian microwave vacuum electronic devices widely used at home and abroad. The active material is mainly composed of calcium aluminate with different molar ratios. Composition of barium salts. With the continuous improvement of the power and frequency of microwave tubes, barium tungsten cathodes have been difficult to meet the requirements of devices for cathode current density, and scandium-containing diffusion cathodes (adding Sc elements to barium tungsten cathodes) have become the most ideal due to their low temperature and large emission characteristics. It is the most import...

Examples

example 1

[0025] Example 1. Dissolve 2.1966 grams of scandium nitrate, 12.3093 grams of ammonium metatungstate, 0.6777 grams of barium nitrate, 0.1531 grams of calcium nitrate, 0.4864 grams of aluminum nitrate, and 10 grams of citric acid in water. First, dissolve scandium nitrate, barium nitrate, and aluminum nitrate Mix with calcium nitrate solution, then add ammonium metatungstate solution, and finally add citric acid solution. The mixed solution was placed in a water bath at 80°C until a sol was formed. It was then dried at 80°C to form a gel. After decomposing the gel at 500°C for 5 hours under atmospheric atmosphere, a yellow powder was obtained. The decomposed powder is subjected to two-step reduction in a hydrogen atmosphere, the first reduction temperature is 500°C, the holding time is 2 hours, the second step reduction temperature is 900°C, and the holding time is 2 hours. Then the powder at 2.5t / cm 3 Press under pressure to form a round cake of Φ3×1.2mm, and then sinter at...

example 2

[0026] Example 2. Dissolve 2.1966 grams of scandium nitrate, 11.6255 grams of ammonium metatungstate, 1.3554 grams of barium nitrate, 0.3062 grams of calcium nitrate, 0.9728 grams of aluminum nitrate, and 10 grams of citric acid in water. First, dissolve scandium nitrate, barium nitrate, and aluminum nitrate Mix with calcium nitrate solution, then add ammonium metatungstate solution, and finally add citric acid solution. The mixed solution was placed in a water bath at 100°C until a sol was formed. It was then dried at 100°C to form a gel. The gel was decomposed at 550°C under an oxygen atmosphere for 5 hours to obtain a yellow powder. The decomposed powder is subjected to two-step reduction in a hydrogen atmosphere, the first reduction temperature is 500°C, the holding time is 2 hours, the second step reduction temperature is 1000°C, and the holding time is 2 hours. Then put the powder at 2t / cm 3 Pressed under pressure to form a round cake of Φ5×1.2mm, and then sintered at...

example 3

[0027] Example 3. Dissolve 2.1966 grams of scandium nitrate, 11.6255 grams of ammonium metatungstate, 1.3554 grams of barium nitrate, 0.3062 grams of calcium nitrate, 0.9728 grams of aluminum nitrate, and 10 grams of citric acid in water. First, dissolve scandium nitrate, barium nitrate, and aluminum nitrate Mix with calcium nitrate solution, then add ammonium metatungstate solution, and finally add citric acid solution. The mixed solution was placed in a water bath at 90°C until a sol was formed. It was then dried at 120°C to form a gel. After decomposing the gel at 550°C for 5 hours under atmospheric atmosphere, a yellow powder was obtained. The decomposed powder is subjected to two-step reduction in a hydrogen atmosphere, the first reduction temperature is 500°C, the holding time is 2 hours, the second step reduction temperature is 850°C, and the holding time is 2 hours. Then put the powder at 1.5t / cm 3 Pressed under pressure to form a round cake of Φ3×1.2mm, and then si...

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