| 摘要 |
PURPOSE:To provide a cathode for electric discharge tube with less deterioration of electron emission characteristics by equipping a substrate having nickel as main ingredient, and specified three layers adhered onto the substrate. CONSTITUTION:A cathode for an electric discharge tube is provided with a substrate body 1 having nickel as main ingredient; a first layer 4 adhered onto the substrate body 1, wherein 0.05% to 5% by weight of oxide scandium is contained in alkaline-earth metal oxide including barium; a second layer 5 adhered onto the first layer 4, wherein at least one type among carbon in group IV, metal such as germanium, or those oxides is contained by 0.01% to 5% by weight in alkaline-earth metal oxide including barium; a third layer 6 adhered onto the second layer 5 and composed of alkaline-earth metal oxide including barium. Occurrence of Joule heat is thus decreased, evaporation of barium is reduced, and deterioration of electron emission characteristics is suppressed. |
