Abstract: An impregnated cathode having a complex porous body of one-body construction which is mounted in a metal sleeve and in which a partition layer made of a porous material having a porosity less than 17% is arranged in close contact with an impregnated layer made of a porous material containing an electron emissive material. The aforementioned porous partition layer takes the place of the conventional partition plate of refractory metal. The impregnated cathode according to the present invention can not only have its size reduced without any difficulty but also enjoy a high emission current density with a remarkably small dispersion.

Abstract: The hot cathode, according to the invention, is constituted by a fritted matrix 1 and a heating filament 4, said matrix being formed from a powder mixture 2 of tungsten and another high work function refractory metal and covered with a high work function refractory metal film 3. FIG. 3.

Abstract: A directly heated type oxide cathode comprising a base made of an alloy containing Ni as a major component and Zr as a reducing agent, a diffusion prevention layer made of Co formed on the base, a coating of Ni powders formed on the diffusion prevention layer, and an electron emissive alkaline earth oxide layer formed on the coating of Ni powders, does not show deformation of Ni powders or peeling of the oxide layer during the production procedures or operation of the cathode.

Abstract: A controlled porosity sheet defining a surface for a thermionic dispenser thode and a method of manufacture. Starting with a generally flat silicon template substrate structure having an array of upstanding microposts 1-25 microns across on 5-100 micron spacings from each other, a layer of metal is deposited on the substrate to surround the microposts and cover the substrate structure to a desired depth. The metal layer is then abraded to a smooth, flat surface which exposes the microposts. Thereafter, the silicon substrate and microposts are completely etched away, leaving a metal sheet having micron-size holes therethrough.

Abstract: In a controlled-porosity dispenser cathode of the type which has a foil w a plurality of holes covering the emitting material so that emitting material is dispensed through the holes to the electron-emitting surface of the foil and electrons are actually emitted through the holes and a small area surrounding each hole, a non-emitting shadow grid is laid down on the surface of the foil in such a configuration that it does not obstruct any of the emitting holes, has the same shape as the control grid, and is substantially in precise registration with the control grid.

Abstract: An oxide-coated cathode used for the electron tubes such as cathode ray tubes and camera tubes, comprising as the base a sintered product principally composed of an alkaline earth metal compound and a high-melting-point metal and having high heat conductivity and low specific resistance, said sintered product being either used singly or layered on a high-melting-point metal body containing a reducible element or elements as impurity, and an oxide cathode material coated on said base, and a method of producing such oxide-coated cathode.

Abstract: In an exemplary embodiment, a metal capillary cathode for electric discharge vessels with an emission substance carrier disk porous on its front face and comprised of metal melting at a high temperature is constructed to prevent lateral emission of electrons (interfering emission). To this end, the disclosure provides that the emission substance carrier disk has a nonporous outer casing surface with a higher electron work function than the outer, active surface of the emission substance carrier disk. Such a dispenser cathode is employed as a metal capillary cathode in traveling wave tubes.

Abstract: A dispenser cathode is fabricated by covering a reservoir of electron emitting material with a perforated metal foil having an appropriate pattern of pore-sized apertures thereon for providing uniform electron emission from the cathode surface. The electron emitting material is in the form of a pellet of barium oxide impregnated with a wax or resinous material to minimize chemical reduction of the barium oxide in air. The impregnated barium oxide pellet is sandwiched between the apertured foil and a support structure to which the foil is welded. During tube bake-out or subsequently during cathode activation, the wax or resinous material evaporates and barium oxide migrates through the apertures to cover the surface of the foil in a uniform manner. The desired pattern of apertures in the foil is achieved by photolithography, or by forming the foil (e.g., by chemical vapor deposition, sputter deposition, evaporation, or sintering) on a substrate containing an array of protruding posts.

Abstract: Emission quantity of thermionic cathodes is increased by including in the potentially emissive material applied to a cathode substrate a quantity of a readily reducible metallic oxide. During cathode processing the metal oxide provides free oxygen gas which aids in binder removal.

Abstract: A thermionic emission cathode comprising a base metal made of nickel-tungsten series alloy, for example an alloy comprising 90 to 70% by weight of nickel and 10 to 30% by weight of tungsten, and an emitter layer, which is formed on the base, made from a mixture of (a) tungsten powder or nickel-tungsten alloy powder comprising 90 to 70% by weight of nickel and 10 to 30% by weight of tungsten, (b) Ba.sub.3 WO.sub.6 powder and (c) zirconium powder or ZrH.sub.2 powder, and if necessary interposing a powder layer between the base and the emitter layer, said powder layer having the same composition as the base metal and a particle size of 1 to 10 .mu.m sealed on the surface of the base with a distribution density of 0.5 to 5.0 mg/cm.sup.2, can be applied to both directly and indirectly heated type cathodes. Said cathode has such advantages as being able to be miniaturized and to have high current density.

Abstract: An oxide cathode wherein a base is made of an alloy comprising Ni as a main component and at least one reducing element selected from the group consisting of Mg, W, Zr, Si, Al and C, and the surface of the base is coated with an alkaline earth oxide layer containing at least BaO, the BaO content in the inner portion of the oxide layer contacting with the base being lower than that in the superficial portion of the oxide layer, if desired, forming a roughened layer made of powdered Ni or the like between the base and the inner portion of the oxide layer, can inhibit the formation of interface layer of, e.g. Ba.sub.3 WO.sub.6 and maintain stable thermion emitting characteristics for a long period of time.

Abstract: A method of producing a nonconsumable electrode comprising forming a blind hole in the working end face of a high-melting core of the electrode, partially filling the blind hole with doping agents and then filling the remaining portion of the hole with a mixture of the doping agents and high-melting core material. The mixture is then heated from the surface of the electrode until a fused surface layer is formed and an enclosed space with doping agents is provided in the electrode.

Abstract: The performance of microwave tubes at very high frequencies is limited by the ability of their thermionic cathodes to provide high emission current density in combination with long life and low evaporation of active material. An improved tube uses a cathode comprising a porous metal matrix consisting of a compacted mixture of tungsten and iridium particles, impregnated with a molten barium aluminate. Other alkaline earth oxides may be used as additives. The impregnated cathode outgasses easily and has a long life because it is not dependent on thin surface films. Thermionic emission is improved compared to a tungsten matrix, and barium evporation is reduced. The combination of power and frequency obtainable from the microwave tube is thereby significantly increased.

Abstract: A thermionic electron emitter comprises a tube of wall thickness less than 0.1 mm, a body of thermionic electron emissive material compressed and sintered in the tube, and a ring, coaxial with the tube, within the body to provide constraint against cracking of the body.

Abstract: An emissive member for a controlled-porosity, dispenser-type cathode comping a three-component sandwich consisting of: (1) a supporting disc; (2) a layer of nonsintered alkaline earth material on said disc; and (3) a thin perforated foil on said layer. The foil is made of refractory metal and has a uniform pattern of tiny holes through which the active material of the reservoir migrates to coat the surface of the foil, the foil thus serving as the electron-emitting surface of the cathode.

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 thin film of a low-thermionic-work-function material is maintained on the cathode of a device for producing a high-current, low-pressure gas discharge by means of sputter deposition from an auxiliary electrode. The auxiliary electrode includes a surface with a low-work-function material, such as thorium, uranium, plutonium or one of the rare earth elements, facing the cathode but at a disposition and electrical potential so as to extract ions from the gas discharge and sputter the low-work-function material onto the cathode. By continuously replenishing the cathode film, high thermionic emissions and ion plasmas can be realized and maintained over extended operating periods.

Abstract: A dispenser cathode for a grid-controlled electron tube in which the emission of surface regions immediately opposite the control grid is reduced by providing projections above the emissive surface of fused, pore-closing portons which have a focussing effect. These projections may be formed by electron beam or laser beam welding.

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.

Abstract: Device comprises an evacuated envelope and a heater-cathode assembly including an electrically-conductive, porous metal body containing electron-emission material and at least two electrically-resistive legs attached directly to spaced positions on the body. Electric current flowing through the legs and body generates heat in the legs, which heat is thermally conducted to the body. The parts are proportioned to reduce radiation losses by minimizing surface area. The structure reduces bulk and mass to permit short heating-up times.