| 摘要 |
PURPOSE:To maintain the electron radiation characteristics of the oxide cathode for a long time by forming the compound layer of BaO and Al2O3 or BaO and SiO2 between the substrate metal and the oxide layer of the electron radiant alkaline earth metal and thus controlling the consumption speed of the reducing agent. CONSTITUTION:Substrate 4 is composed of the plate material formed by the alloy of 30mum of 27.5 wt% W, 1.0 wt% Zr and the rest of Ni. And compound layer 5 of 5 mol BaO and 2 mol Al2O3 and with 5mum is coated on the upper surface of substrate 4. Furthermore, oxide layer 3 composed of three elements (Ba-Sr-Ca) is coated on the surface of layer 5, thus forming the oxide cathode. In such oxide cathode, the reducing agent Zr within substrate 4 features a low reaction to layer 5, and thus the supply of Zr onto the surface of substrate 4 is reduced. Accordingly, the consumption speed is suppressed for the reducing agent under operation. |
