Abstract: A reactionless thermionic cathode for electronic tubes consists of a metallic or ceramic support and an alloy, preferably an intermetallic compound, containing the actual emission-promoting element, with a metal from the group comprising those of the VIIIth vertical row of the periodic table and rhenium. The preferred activation substances are platinides of the elements having a low electron work function, predominantly Ba and La. The cathode is manufactured by wet-mechanical, cataphoretic or electroplating application of the activation substance to the support or by infiltration of the porous support having a pore volume of at least 10%. High emission current densities are obtained at relatively low operating temperatures.

Abstract: A hot-cathode material in wire or sheet form, comprising a high-melting carrier metal, an oxide activator and a carbide reducing agent, and, optionally, a diffusion-promoting additive, the material comprising a core zone and at least one surface layer having different compositions or different concentrations of constituents therein which are such that, in operation, the rate of diffusion of the activator from the core zone is equal to or greater than the loss of activator from the surface layer. The material is made by a powder metallurgy/thermo-mechanical process.

Abstract: A gas discharge vessel and a process for extending the life of a gas discharge vessel, which is used as a radiation source, is permeable to radiation of a wavelength from 10 to 1,000 nm and has an activated cathode, wherein a metal oxide, of which the free enthalpy .DELTA.G, under the pressure and temperature conditions prevailing in the vessel, is both greater than the free enthalpy of the oxides, from which the vessel is constructed, and greater than the free enthalpy of any oxide or suboxide of the element constituting the activating substance applied to the cathode is introduced in the discharge path.

Abstract: A reaction thermionic cathode of the diffusion type on the basis of an activated high-temperature support metal doped with a diffusion-promoting additive for the activator substance, provided with a barrier layer inhibiting the self-diffusion of this additive in an undesired direction.

Abstract: A thermionic cathode of tungsten or molybdenum is made with an activating content of lanthanum oxide and is supplied with a carbonaceous reducing agent either by incorporation in the bulk material of the cathode body or by carburizing, so that the reducing agent comprises at least in part a carbide of the carrier metal. Lower operating temperatures and higher emissivity are obtained compared to thoriated tungsten filaments and longer useful life compared to other cathodes activated by other rare earth oxides. The temperature-emissivity characteristics are such that good results are obtainable even within the temperature range in which molybdenum is usable as a carrier material.

Abstract: A reaction cathode with high thermic emission which is especially suited for vacuum tube application and which contains a compound of a monolayer forming element which is liberated by a supply reaction which proceeds during the operation of the cathode, wherein the monolayer forming element is at least one of the elements selected from the group consisting of yttrium and lanthanum, and wherein said cathode further contains at least one metal selected from the group consisting of palladium, platinum, rhodium and ruthenium, as a diffusion-enhancing agent.