| 摘要 |
PURPOSE:To obtain a stable radiating characteristic under a high current density for a long time by making an electron radiating material layer to contain a specific amount of Sc2O3 and a heat-resisting metal. CONSTITUTION:An electron radiating material layer 2a coating the base upper part of a base body contains Ba at least, besides having an alkaline earth metal oxide containing Sr or/and Ca as a main component and containing Sc2O3 of 0.1-20wt.% and 0.01-0.05wt.% of a heat-resisting metal (Ti powder). A composite oxide, which is a high-resisting layer segregated near the interface of the base body 11 can be dissociated by adding thin Sc2O3 so that a sufficient electron emitting characteristic can be obtained under a high current density. Further, the activity of the electron radiating material layer 2a can be maintained for a long time by adding the heat-resisting metal (Ti power). |
