| 摘要 |
PURPOSE:To make high current density operation stable for a long period of time by providing a W powder layer on a substratum metal, and forming thereover an electron emitting substance layer consisting of alkali earth metal oxides and rare earth metal oxides. CONSTITUTION:A substratum metal 1 is welded to a sleeve 4, and surface contaminant and/or oxide layer is removed by a heat treatment. W powder, Ag nitride as binder, and organic solvent such as butyl acetate are mixed uniformly and applied to the metal 1, and thereby a W powder layer 5 is produced. A suspension liquid is prepared by mixing a powder 21 of alkali earth metal carbonate and a powder 22 of rare earth metal oxide, and with butyl acetate and/or cellulose nitrate, and is applied to this W powder layer 5, followed by drying process to yield an electron emitting substance layer 2. Accordingly the W power layer 5 promotes production of excessive Ba to enable operation with high current density, and further the bond of metal 1 with layer 2 is strengthened to lead to enhancement of the reliability. |
