| 摘要 |
PURPOSE:To prolong the service life while preventing exhaustion of Sc in a Sc system impregnated cathode having a thin film layer including Sc on the surface thereof by adding the supply source into the above thin film surface. CONSTITUTION:An impregnated cathode 1 is formed in such a manner that a porous base body having a porosity of 28%, which is prepared by pre-sintering in hydrogen and sintering in vacuum a press-moulded tungsten powder, is infiltrated in hydrogen with an electron emitting material composed of 4BaO-Al2O3- CaO. On the surface of the cathode 1, there is formed a compound thin film layer 5 which is prepared by adding a mixture or compound of Re, Os, Ru, Pt, W, Ta, Mo or the like including Sc onto a thin film layer compound of an oxide including W and/or Sc, and therefore it is possible to easily supply, on the surface of the cathode 1, Sc which is a molecular layer component of (Ba:Sc:O) necessary for improvement in an electron emitting characteristic. |
