Preparation of Nanocomposite Thoriated Tungsten Cathode by Swaging Technique

By using the high energy ball milling method, the nanosized ThO2 powders were obtained. Through mixing powders, sintering and hot swaging processing, a nanocomposite thoriated. tungsten cathode was fabricated. The relative density of the nanocomposite material is near 100%. The microstructure of nanocomposite cathode is quite different from that of conventional thoriated tungsten cathode. Most of thoria particles are less than 100 nm in diameter, and distribute on the boundaries of tungsten grains. The nanocomposite cathode shows a much lower arc starting field than that of conventional cathode, which will improve the performance of the cathode significantly.