| 摘要 |
543.641. Thermionic electrodes. NAAMLOOZE VENOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN., and POLLAK, J..E. (Naamlooze Venootschap Philips' Gloeilampenfabrieken). May 20, 1940, No. 8945. Addition to 484,548. [A Specification was laid open to inspection under Sect. 91 of the Acts, Nov. 23, 1940.] [Class 39 (i)] Electron emitting material as claimed in the parent Specification-comprising a mixture of basic and acid oxides-has added thereto a larger quantity by weight of tungsten or molybdenum ; this material is mounted on a support with the interpositioning of a poor heat conductor. Alkaline earth oxides may be added to the emitting material one example of which is formed by mixing together given quantities of thorium oxide, barium and strontium carbonates, solution of nitrocellulose in amy-acetate, amy-acetate and tungsten powder and grinding this mixture. To this is added finely ground quartz and the whole is ground again. This paste is applied to a support made of tungsten to which a heat insulating layer has been applied the electrode being heated in a reducing-nitrogen, hydrogen-atmosphere at about 2,200‹ C. until sintering occurs. The insulating layer may consist of the material described in the parent Specification. |
