| 摘要 |
<p>PURPOSE:To extend the service life, of the cathode in the headline by a method wherein a base metal consists of 3 layers which differ in the concentration of reducing metal or in the kinds of reducing metal, while the concentration of 1st reducing metal is higher in the 2nd layer than in the 1st layer, and the 3rd layer includes the 2nd reducing metal, and the 1st layer is coated with electron emitting material. CONSTITUTION:A base metal is made in 3-layer structure including 0.02% of Si in the 1st layer 1 and 0.12% of Si in the 2nd layer 2, and the 3rd layer 3 is made of nickel chrome alloy which includes 20% of Cr. An object is formed by subjecting such raw material as in this laminated structure to press processing as shown in fig. (a). Then 1st and 2nd layers on the side wall of the cylinder part are removed as shown in fig (b) by photoetching technique. Thus, the top works as a base metal and the rest works as a cylindrical supporter for the top, and later, the top is coated with electron emitting material to be an oxide negative electrode. Cr takes over the role of Ba generation and the rate of Ba generation is maintained at a high level for at least 20,000hr from the onset by Si and Cr. As for the fluidity, thickness of the base metal top can be made thinner than conventional ones. By this constitution, high current density longer service life and high speed operation of a negative electrode made of oxide are made possible.</p> |
