General Electric Company

Electric Power Research Institute Incorporated

Stephan P Mitoff

Robert W Powers

Wayne D Pasco

Richard J Charles

Manfred W Breiter

Randall N King

Walter L Roth

Edward Szymalak

Vincent J DeCarlo

A process for producing an hermetic feedthrough in a ceramic substrate by providing a sheet of liquid phase sinterable ceramic composition having a feedthrough hole, filling the feedthrough hole with refractory metal metallization material, firing the resulting structure to produce a sintered substrate and adherent metallization wherein the metallization is comprised of continuous phases of refractory metal and glass, contacting the refractory metal with electrically conductive intrusion metal and heating the resulting structure to a temperature at which the glassy phase is fluid, the refractory metal is solid, and the intrusion metal is liquid whereby the liquid metal preferentially wets the refractory metal, migrates into the metallization displacing glass and, upon subsequent solidification, partially or wholly occupies the volume space originally containing the continuous glass phase.

Hermetic feedthrough in ceramic substrate

Method of making hermetic feedthrough in ceramic substrate

A process for increasing electrical conductance of a metallization on a ceramic substrate wherein the metallization is an intermixture of continuous phases of refractory metal and glass which comprises contacting the refractory metal with an electrically conductive intrusion metal and heating the resulting structure to a temperature at which the glassy phase is fluid, the refractory metal is solid, and the intrusion metal is liquid whereby the liquid metal preferentially wets the refractory metal, migrates into the metallization displacing glass and, upon subsequent solidification, partially or wholly occupies the volume space originally containing the continuous glass phase.

Secondary metallization by glass displacement in ceramic substrate

A sintered .beta.-alumina cylindrical tube of uniform shape is produced by placing the unsintered tube within a sagger, passing the sagger on friction-reducing balls through a horizontal firing tube and rotating the tube-containing sagger through the firing tube.

Production of .beta.-alumina ceramic tubes

A sintered .beta.-alumina cylindrical tube of uniform shape is produced by placing the unsintered tube within a sagger, passing the sagger on friction-reducing balls through a horizontal firing tube and continuously alternately rotating the tube-containing sagger through the firing tube so that all portions of the tube therewithin experience on the average the same gravitational effect.

A sodium-sulfur cell is disclosed herein along with a method of constructing its sulfur electrode. The cell includes means containing a supply of sodium, an elongated housing joined at one end with sodium containing means, a beta-alumina electrolyte tube located within and extending from the joined end of the housing so as to define a compartment within the housing around the tube. A mixture including sulfur and an electrically conductive filler is disposed within the compartment and forms the cells sulfur electrode. In constructing this electrode, sufficient space is initially provided within the cell compartment around the beta-alumina electrolyte tube to allow for expansion of the sulfur when the latter converts from its solidified state during initial storage to its molten state during operation of the cell, thereby minimizing the possibility of damage to the electrolyte tube as a result of this expansion.

Sodium-sulfur cell with method of constructing the sulfur electrode

In a sodium sulfur cell including a beta-alumina separator between the sodium and sulfur compartments, high surface area gettering means, e.g., beta-alumina or beta'-alumina, for potassium and alkali earth metal ion impurities in the sodium to protect the separator. The gettering means is disposed in the sodium container in the form of particles or a continous porous shell or porous solid plug adjacent to the separator.

Sodium sulfur cell

Molten sodium is filled into a reservoir insert container including a closed ended tubular portion and the sodium is solidified and the container sealed. Then an open port is provided for the insert container. The container is placed into the sodium compartment of a sodium-sulfur cell so that the tubular portion extends into the electrolytic separator tube of the cell and is spaced apart therefrom forming an annular chamber. To activate the cell, the sodium is melted and flows through the open port into the annular chamber.

Sodium insert container for a sodium-sulfur cell and method

Methods are described for making an improved sensing element and an improved sensor assembly for a halogen gas leak detector. The method of making an improved sensing element includes positioning at least one porous ceramic tubular element doped with sodium carbonate in a high temperature, non-reactive container, surrounding and covering the element with sodium beta-alumina particles, and baking the element in a furnace overnight at a temperature in the range from 1400.degree. C. to 1450.degree. C. The method of making an improved sensor assembly includes the above steps after which a helical heater coil is wrapped snugly around the tubular element, and a platinum wire electrode is positioned substantially within and supported by the tubular element. A suitable cement is applied over the entire helical heater coil and the immediate juxtaposed portions of the tubular element. The sensor assembly is then surrounded by and covered with sodium beta-alumina in a high temperature, non-reactive container. The cement is then cured at 1300.degree. C. for one to three hours.

Methods of making an improved sensing element and an improved sensor

A composite body has a beta-alumina substrate with at least one aperture therethrough, and a glass coating covering and adhering to the entire external surface of the substrate. The glass coating has sodium resistance, low alkali ion-conductance, and a coefficient of thermal expansion of 7.3 to 6.1 .times. 10.sup.-6 inches/inch/.degree. C.

Composite body with beta-alumina substrate and glass-coating thereon

Improved sodium-sulfur batteries are provided by enhancing the utilization of active positive-electrode material. In sodium-sulfur batteries, employing a liquid sodium electrode separated from a liquid sulfur electrode by a solid .beta.-alumina electrolyte separator, where the sulfur is impregnated in an electronically conducting matrix such as porous carbon, enhanced utilization of active electrode material is achieved during the charging-discharging cycling by enhancing the electronic resistivity adjacent the .beta.-alumina in the sulfur electrode. This can be achieved in a variety of ways, particularly employing porous carbon of higher resistivity adjacent the .beta.-alumina as compared to the porous carbon distant from the .beta.-alumina.

Efficient sodium/sulfur battery

A method of forming a beta-alumina article includes electrophoretically depositing such material on a mandrel, exposing the deposited material promptly to a continuous flow of warm air thereby drying the deposited material, and sintering the dried material. Alternately, the deposited material is stored in a chamber purged continuously with an inert gas until the material is dried in a flow of warm dry air. Such articles are useful as solid electrolytes in sodium-sulfur and sodium halogen batteries.

Method of forming beta-alumina articles

A battery casing and a sealed sodium-sulfur battery are disclosed wherein the battery casing includes separate seals of low temperature melting glass joining a portion of an inner casing of a solid sodium ion-conductive material to the interior surface of a ceramic ring, and joining two opposed outer metallic casings to the ceramic ring. A sealed sodium-sulfur battery has the above type of casing with a sodium anode in one casing and a cathode of sulfur in conductive material in the other casing.

Battery casing and hermetically sealed sodium-sulfur battery

A cell casing and a hermetically sealed sodium-sulfur cell are disclosed wherein the cell casing includes a hermetic mechanical seal joining two opposed outer metallic casing portions to a ceramic ring supporting an inner casing of a solid sodium ion-conductive material. A hermetically sealed sodium-sulfur cell has the above type of casing with a sodium negative electrode in the inner casing and a positive electrode of sulfur in conductive material in an outer casing portion surrounding the inner casing.

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Clifton Park, NY, United States of America

Stephan P Mitoff