Using Impregnation Method for Barium Tungsten Electrodes Production

Using impregnation method to produce barium tungsten electrode it has good emission properties, high current density, smooth electrode surface and long service life and other good performance. However, this method has the disadvantage of complex processes and processing difficult.

To produce barium tungsten electrode by impregnation method there are two elements, tungsten cavernous spongisum and emitting material and the production processes are as following:

1. Tungsten cavernous spongisum production:
Raw materials: tungsten powder (250 mesh / cm2): 97g, paraffin: 3g, aviation gasoline: 30~40cc, glycerol;
Production processes: Pour gasoline into paraffin to make paraffin melted, then pour them into tungsten powder (about 180 ℃) with rapid stirring, until the smell of gasoline is gone. And then compress it into blocks. The compacted tungsten powder was processed low-temperature sintering, and before sintering temperature slowly raised to 600 ℃the temperature is 100~150 ℃/ h, but at 600 ~ 1400 ℃ the temperature is 200 ℃/h (heating preservation for 1 hour). When the temperature at 1700℃ the product is molding. Finally, high temperature sintering, high temperature sintering temperature is about 2000 ℃ (about half an hour).

2. Emitting material: barking barium aluminum in oven at about 100 ℃,after grinding and compressing put it into molybdenum boat for sintered with Al2O3 doping when the sintering temperature reaches to 700 ~ 800 ℃, heating preservation for 1 hour, when the sintering temperature is 1400 ℃, heating preservation for 2 hours, after sintering pulverized it into pieces to get finished.

3. Barium tungsten electrode: putting barium aluminum into nitrocellulose stir into a paste, applied to the surface of the tungsten cavernous. And then burn to 1750 ℃, until the product surface shows light green color. Then the sintered electrode in pumping quartz vessel prepared products roast vacuum high frequency. Finally, the electrodes are placed dried in a vacuum environment for storage.

Barium tungsten electrode Use Notes:
1. Can not make it wet or long-term exposure to the atmosphere, deposited in a vacuum state for the best;
2. Can not direct contact with the to prevents sweat marks shows on the surface of the electrode;
3. Electrode texture is light and crispy, using gently;
4. Improper storage electrode surface will oxidation, you can process burn hydrogen treatment to remove surface dark spots, and then continue to use;
5. The transmission side of electrode has cracks or broken, to stop using it.

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