Barium tungsten electrode is a composite electrode material made of tungsten (W) and barium (Ba) compounds, mainly used in electron emission devices such as cathode ray tubes (CRTs), X-ray tubes and electron guns. It combines the high melting point, corrosion resistance and mechanical strength of tungsten with the low work function characteristics of barium to achieve efficient thermal electron emission.
Barium tungsten electrodes are usually composed of the following two parts:
Tungsten Substrate: Tungsten is a high melting point metal (melting point is about 3422°C) with good conductivity and corrosion resistance, and can maintain structural stability at high temperatures.
Barium Oxide Layer: The barium compound (such as barium oxide) coated on the surface can significantly reduce the work function of the electrode, making it easier for electrons to be emitted.
Working Principle of Barium Tungsten Electrode:
When in use, the barium tungsten electrode is heated to about 1000-1200°C. At this time, the barium atoms in the barium oxide layer will diffuse to the surface to form an active barium film. This film further reduces the work function and promotes thermal electron emission, thereby improving the emission efficiency.
Main Advantages of Barium Tungsten Electrodes:
High Emission Current Density: It can provide higher electron emission current at lower temperature, suitable for high power devices.
Long Life: The heat resistance and corrosion resistance of the tungsten substrate ensure the long-term stability of the electrode under high temperature and vacuum environment.
Quick Start: Due to the low work function, the electron emission response is fast.
Good Stability: It can still maintain performance under harsh working conditions.
Limitations Of Barium Tungsten Electrodes:
Complex Fabrication Process: high temperature sintering or melting and other steps are required, and the cost is high.
High Environmental Requirements: It needs to be used in a vacuum environment, is susceptible to contamination, and needs to prevent barium evaporation.
Application Areas of Barium Tungsten Electrodes:
Barium tungsten electrodes are widely used in electronic devices that require high electron emission current and long life, such as vacuum electronic devices such as cathode ray tubes (CRTs), X-ray tubes, and electron guns.
