| 摘要 |
PURPOSE:To improve consumption resistance of cathode filaments by forming discharge covering layer of an electron discharge material or ion plant layer containing rare earth metal and boron on the surface of an electrode base metal in a vacuum or inactive gas atmosphere. CONSTITUTION:A thin covering layer 31 of an electron discharge material is formed on the surface of a base material 4 of a heat resistant metal, the electron discharge material bonding thereon by diffusion. As the electron discharge material, those composed of Ba, Ca, and Sr containing rare earth elements such as La, Pr, and Ce; and boron B are used. For example, a covering material tip 3 is attached to an end chuck 2 and the tip 3 facing to the base material 4 repeats touching and detaching thereto by the vibration of a vibrator 1 and the inside of an airtight vessel 6 is supplied with inactive gas from a gas cylinder 8 while being evacuated by a vacuum pump 7. Discharging occurs when the covering material tip 3 comes down close to the base material 4 and the tip material 3 melted by the discharge heat is deposited to the base material 4 and in each vibration cycle, the tip material 3 is repeatedly coated inside the base material in a partly diffused state by the discharge current. |
