Alloy solder for dipping barium tungsten cathode and welding method thereof

Abstract

The invention discloses alloy solder for dipping a barium tungsten cathode and a welding method thereof. The alloy solder consists of cobalt powder and tungsten powder which respectively have the average grain size of between 1 micrometer and 10 micrometers and the purity of between 99.0-99.99 percent and are fully mixed after hydrogen purification. The welding method mainly comprises the two steps of: preparing the alloy solder and welding a tungsten cake and a cathode cylinder. The invention has the beneficial effects that the melting point temperature of the alloy solder has good moderate flowing property and less evapotranspiration, is between the working temperature and the melting point temperature of a cathode activity material and can not cause the precipitation of the cathode activity material in the welding process; with the adoption of the alloy solder and the welding method, the tungsten cake dipped into the cathode activity material forms an effective welding with a molybdenum tube on a whole contact surface; and the alloy solder has high repeatability, stability and reliability.

Description

technical field [0001] The invention relates to a cathode solder and a welding method, in particular to an alloy solder for impregnating a barium-tungsten cathode and a welding method. Background technique [0002] At present, as an electron source, impregnated barium tungsten cathodes are widely used in various microwave devices. In its preparation process, the welding between the tungsten cake and the cathode cylinder supporting it is an essential process. Usually, the connection between the tungsten cake in the cathode and the cathode cylinder (the general material is molybdenum) is accomplished by electron beam welding, laser beam welding, etc. However, these traditional methods have their own drawbacks and cannot meet the performance requirements of modern microwave devices. For example, during electron beam welding and laser beam welding, due to the characteristics of refractory metals of tungsten and molybdenum, the energy required for welding is very high. If the p...

AI Technical Summary

Problems solved by technology

For example, during electron beam welding and laser beam welding, due to the characteristics of refractory metals of tungsten and molybdenum, the energy required for welding is very high. If the protection measures are not appropriate, it is easy to cause cathode oxidation and reduce the emission performance of the cathode; and often after welding It is only the combination of the surface of the welded part, and it is difficult to ensure that the entire circumference of the welded part is tightly welded. After the vibration test and environmental test, cracks often appear in the weld, resulting in the offset or even separation of the tungsten cake and the cathode cylinder.

The cathode thus made cannot adapt to complex weather and terrain, has short service life, poor reliability and stability