| 摘要 |
630,624. Cathode materials and processing. COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. March 4, 1947, No. 6170. Convention date, March 5, 1946. [Class 39 (i)] Indirectly heated cathodes for thermionic valves are manufactured by embedding a heating filament F, Fig. 1, insulated by a thin coating of a substance such as periclase or magnesite which is deposited on the filament by cataphoresis, in a powder of such metals as nickel or tungsten, with optional additions of aluminium, magnesium or titanium, which is compressed and heat treated to form a pellet P which may be shaped like a tennis racquet, having the filament leads f<1>, f<2> embedded in the handle, and which receives the emitting substance on its surface. According to an alternative method of manufacture, twin half-pellets P, Fig. 2, having grooves E to contain the filament, are pressed together and baked, use being made in some cases of an intermediary substance in the form of a metallic paint. The Specification as open to inspection under Sect. 91 comprises also the inclusion of metals such as magnesium and barium in a cathode according to the invention, said metals vaporizing in vacuo and condensing on cold portions of the bulb, thus providing a method of manufacturing photo-electric cells, or a method of gettering. It is also stated that the method according to the invention may be applied to the manufacture of emitting anodes. This subject-matter does not appear in the Specification as accepted. |
