| 摘要 |
831,133. Cathode materials and processing. GENERAL ELECTRIC CO. June 25, 1956 [June 28, 1955], No. 19606/56. Drawings to Specification. Class 39(1). A thermionic cathode consists of a metal base, a porous layer of metal particles alloyed together and to the base by titanium or zirconium, and an emissive coating impregnating and overlying the porous layer. If the emissive coating is an alkaline earth carbonate, the base metal may suitably be nickel, iron, or platinum, and the porous layer may be formed from a powdered mixture of one of these three with titanium or zirconium (or the hydrides thereof). If the emissive coating is thorium oxide, which involves a higher operating temperature, the base metal may more suitably be tungsten or tantalum, and the porous layer formed from a powdered mixture of tungsten with zirconium. The alloying is carried out by vacuum firing, and suitable times and temperatures are given for various combinations of materials. The emissive material, suspended in a binder, is then painted on. The titanium or zirconium also acts as a getter. |
