Manufacturing Process of Barium Tungsten Electrode

Barium tungsten electrode is a material widely used in electron tube cathodes, and is valued for its good emission performance and stability. The manufacturing process of barium tungsten electrode is mainly based on the impregnation method, which can effectively avoid the problems of barium volatilization and uneven distribution that may be caused by direct mixed sintering. It is a relatively mature and commonly used process.

The preparation of barium tungsten electrode usually includes the following main steps:

1. Preparation of Porous Tungsten Matrix

Tungsten powder pressing: Select high-purity tungsten powder and make a porous tungsten blank by pressing and molding.

Sintering: Sinter the tungsten blank at high temperature (about 2000°C) to form a porous tungsten matrix with a certain porosity (usually 15%-25%). The control of porosity is crucial to the subsequent impregnation effect.

2. Impregnation of Barium Compounds

Preparation of impregnation solution: Usually a mixture of oxides or carbonates containing elements such as barium, calcium, and aluminum is used, such as the BaO-CaO-Al₂O₃ system.

Impregnation process: Immerse the porous tungsten substrate in the molten impregnation liquid, so that the impregnation liquid penetrates and fills the pores of the tungsten substrate.

Cooling: Slowly cool to solidify the impregnation liquid in the pores to form a stable structure.

3. Surface Treatment

Remove excess impregnation: Remove excess impregnation on the electrode surface by mechanical processing or chemical cleaning to ensure a clean surface.

Heat treatment: Heat treatment is performed in a vacuum or protective atmosphere to allow the impregnation to react appropriately with the tungsten substrate to form a stable emission layer.

4. Packaging And Testing

Installation: Install the treated barium tungsten electrode into an electron tube or other vacuum device.

Activation: Activation treatment is performed by heating to generate free barium atoms on the electrode surface, thereby enhancing the emission performance.

Performance test: Test key parameters such as emission current and life to ensure that the electrode meets the use standards.

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