Showing papers on "Diffusion barrier published in 1974"
Patent•
11 Nov 1974TL;DR: An improved nuclear fuel element is disclosed for use in the core of nuclear reactors in this article, which has a metal liner and a diffusion barrier disposed between the cladding and the nuclear fuel material.
Abstract: An improved nuclear fuel element is disclosed for use in the core of nuclear reactors. The improved nuclear fuel element has a metal liner and a diffusion barrier disposed between the cladding and the nuclear fuel material. The diffusion barrier is in the form of a metal coating with the diffusion barrier being coated on the internal surface of the cladding in one embodiment and the diffusion barrier being coated on the outside surface of the metal liner in another embodiment. The diffusion barrier is a coating of chromium or a chromium alloy and serves to prevent any alloying or formation of low melting eutectic liquid phases between the metal liner and the cladding at elevated temperatures. The metal liner is selected from the group consisting of stainless steel, copper, copper alloys, nickel, and nickel alloys.
31 citations
Patent•
28 Jan 1974TL;DR: In this paper, a thin layer of a ductile diffusion barrier, which is non-poisonous to thermoelectric materials, such as iron, tungsten, molybdenum, or niobium, is disposed between the material and a contacting shoe.
Abstract: A bonded electrical contact and method for a thermoelectric element A thin layer of a ductile diffusion barrier, which is non-poisonous to thermoelectric materials, such as iron, tungsten, molybdenum, or niobium, is disposed between the thermoelectric material and a contacting shoe, such as stainless steel, which has poisonous alloy constituents The thermal expansion coefficient of the diffusion barrier, which does not match that of the thermoelectric material, is overridden by that of the shoe, whose coefficient does correspond with that of such high expansion thermoelectrics as the telluriden
19 citations
TL;DR: In this paper, a study has been made of the preparation and the stabilization of silver surfaces that are suitable as field electron emitters, showing negligibly distorted FEM patterns, by in-situ deposition of silver vapour onto the apex of thermally cleaned blunt tungsten tips.
11 citations
Patent•
7 Feb 1974TL;DR: In this article, an improved hydrogen detector for use in sodium cooled reactors is presented. The improved detector basically comprises a diffusion tube of either pure nickel or stainless steel having a coating on the vacuum side (inside) of a thin layer of refractory metal, e.g., tungsten or molybdenum.
Abstract: An improved hydrogen detector for use in sodium cooled reactors. The improved detector basically comprises a diffusion tube of either pure nickel or stainless steel having a coating on the vacuum side (inside) of a thin layer of refractory metal, e.g., tungsten or molybdenum. The refractory metal functions as a diffusion barrier in the path of hydrogen diffusing from the sodium on the outside of the detector into the vacuum on the inside, thus by adjusting the thickness of the coating, it is possible to control the rate of permeation of hydrogen through the tube, thereby providing a more stable detector.
9 citations
Patent•
21 Nov 1974TL;DR: In this paper, a dielectric substrate is provided with a thin narrow heater strip of multi-layer metallic films of noble metals such as platinum and gold, which is bonded to the substrate and it has terminal means comprising a silver film electrode that is spaced away from the film heater.
Abstract: A dielectric substrate is provided with a thin narrow heater strip of multi-layer metallic films of noble metals such as platinum and gold. The film heater is bonded to the substrate and it has terminal means comprising a silver film electrode that is spaced away from the film heater. A metal oxide diffusion barrier such as a tin oxide film bridges the gap between the film heater and the silver electrode and retards the electromigration and mass flow between the film heater and the electrode.
8 citations
Patent•
28 Jan 1974TL;DR: In this article, an insulating substrate is first coated with a film of tantalum and then either a layer of copper or two layers of copper separated by a diffusion barrier layer of iron, nickel or cobalt are applied by sputtering to metallize the surface.
Abstract: An insulating substrate is first coated with a film of tantalum Then either a layer of copper or two layers of copper separated by a diffusion barrier layer of iron, nickel or cobalt are applied by sputtering to metallize the surface With a photolithographic mask to protect the circuit and component pattern, the copper and tantalum are etched to bare the substrate Then with a screen printed mask, the copper is selectively etched over resistor and capacitor regions, and the tantalum there is partially oxidized, the copper conductors and contact areas being protected A soft solder is then applied to the copper, but does not stick to the oxide
8 citations
Patent•
10 Oct 1974TL;DR: In this article, the sputtering in a discharge of a monatomic gas containing 0.5 to 16% of air, nitrogen or oxygen was carried out to make a solder-fast contact layer, which made it resistant to alloying with a solution in solder.
Abstract: Copper is sputtered onto a substrate to make a solder-fast contact layer by carrying out the sputtering in a discharge of a monatomic gas containing 0.5 to 16% of air, nitrogen or oxygen which reduces the conductivity of the copper layer, but makes it resistant to alloying with a solution in solder, to an extent comparable with the results obtained by the provision of intermediate diffusion barrier layers. Best results are obtained in an argon discharge in the presence of an admixture of nitrogen or air between 2 and 4% by volume. The solder-wetting properties are not impaired.
8 citations
Patent•
4 Apr 1974
TL;DR: In this paper, if polyvinyl butyral (PIB) is used as bonding film or outer sheet the layer of PUDC is arranged between the glass and the bonding film.
Abstract: Pref. if polyvinyl butyral (PIB) is used as bonding film or outer sheet the layer of PUDC is arranged between the glass and the bonding film. The PUDC can be a film or applied as a coating substance and it can be opt. coated.
3 citations
TL;DR: In this paper, a stabilized tantalum-gold thin film system on quartz substrates has been investigated as a metallization system for microwave power transistors, where the tantalum was used as the barrier metal in order to minimize interdiffusion and eutectic formation between the gold and silicon.
Abstract: A stabilized tantalum-gold thin film system on quartz substrates has been investigated as a metallization system for microwave power transistors. The stabilized tantalum was used as the barrier metal in order to minimize interdiffusion and eutectic formation between the gold and silicon. In order to stabilize the tantalum against rapid diffusion of gold at tantalum grain boundaries, a 200–300A film of platinum was deposited between 1000A layers of tantalum. The resulting structure was then overlaid with 3000A of sputtered gold. The present investigation has shown that the Au/Ta-Pt metallization is (1) metallurgically stable with no significant degradation of resistivity below 500°C, (2) resists electrochemical corrosion and (3) is readily processed with existing technology.
3 citations
TL;DR: In this paper, a diffusion-barrier coatings which can effectively reduce the interaction of refractory filaments such as tungsten and tantalum with a nickel-alloy matrix is presented.
Abstract: A new approach to the development of diffusion-barrier coatings which can effectively reduce the interaction of refractory filaments such as tungsten and tantalum with a nickel-alloy matrix is presented. This consists of reacting the oxide film deliberately grown on these metals with a nickel coating prior to fabricating the composite. The nickel-oxide film reactions proceed under vacuum conditions in the temperature range 650 to 800° C with the formation of intermediate phases which produce sufficiently strong bonds for composite strengthening.
2 citations