| 摘要 |
<p>PURPOSE:To obtain an electron tube cathode with little life dispersion by setting the ratio that a nickel powder sintered layer formed on the upper face of a nickel substrate covers the upper face of the nickel substrate within a specific range. CONSTITUTION:A nickel powder sintered layer 4 with the coating ratio 3-50% is formed between the nickel substrate of a cathode and an electron emitting material layer 2 dispersed with scandium oxide 2b powder. The function to generate free barium and the function to improve the conductivity of the electron emitting material layer 2 are attained by the composite oxide generated by the scandium oxide 2b dispersed in the electron emitting material layer 2, the generation of an intermediate layer is controlled by the nickel powder sintered layer 4, and the reduction of conductivity is prevented. The fluctuation of emission characteristic is reduced, and the stable thermoelectron emission characteristic with a long life is obtained.</p> |
