Abstract: A method is provide for preparing potassium metal which comprises embedding a polycrystalline alkali metal ??-Al2O3 molding in an oxidic powder containing potassium and aluminum of a molar K2O:Al2O3 ratio within the range of 1:(x?1) to 1:(x+1), the weight of oxidic powder amounting to at least two times the weight of the molding; heating the embedded molding at a rate of at least 100° C. per hour to at least 1100° C.; and further heating to at least 1300° C., this temperature being maintained for at least one hour prior to cooling.

Abstract: A method is provide for preparing potassium metal which comprises embedding a polycrystalline alkali metal ??-Al2O3 moulding in an oxidic powder containing potassium and aluminium of a molar K2O:Al2O3 ratio within the range of 1:(x?1) to 1:(x+1), the weight of oxidic powder amounting to at least two times the weight of the moulding; heating the embedded moulding at a rate of at least 100° C. per hour to at least 1100° C.; and further heating to at least 1300° C., this temperature being maintained for at least one hour prior to cooling.

Abstract: A solid polycrystalline potassium ion conductor having a ??-Al2O3 structure, its production, and the preparation of potassium metal using this potassium ion conductor.

Abstract: A thermoelectric material in a shape for forming part of a thermoelectric module, the thermoelectric material is coated with a protective layer to prevent degradation by humidity, oxygen, chemicals or thermal stress.

Abstract: In a thermoelectric module comprising a series of p and n type semiconductors connected in series by conductive contacts, the conductive contacts are in contact with a substrate of moderate to high thermal conductivity that is electrically insulated from the conductive contacts by a resistive surface layer comprising a ceramic material.

Abstract: In a sodium sulphur cell having a porous matrix forming an electronic conductor in the cathodic region and extending between the surface of the solid electrolyte and a cathode current collector, this matrix is a composite comprising a first material formed of graphite or carbon of a material coated with graphite or carbon, which first material is intimately mixed with a second material, such as alumina fibres, which is more easily wetted by the polysulphides than is the first material.

Abstract: Beta-alumina ceramic articles of improved strength and durability particularly for use in sodium sulphur cells are produced by compacting beta-alumina particles or a mixture of powders which react to form beta-alumina, sintering the compacted material in air or oxygen to form an impervious polycrystalline ceramic body and then further densifying the sintered body by subjecting it to the direct isostatic pressing action of a fluid, e.g. a gas at a pressure of at least about 5,000 psi and at a temperature between 1200.degree. C and 1500.degree. C which is above the elastic/plastic transformation, said fluid being inert and non-permeating with respect to said fired body and subsequently cooling the body under pressure to a temperature below the elastic/plastic transformation.

Abstract: In making .beta.-alumina ceramic articles by a fast firing technique in which the green shapes of compressed powder material are sintered by passing them continuously through a tubular furnace, the furnace is sloped upwardly to give convective air flow forwardly through the furnace at a speed not less than the speed of movement of the article or other means are provided for causing such an air flow or flow of other oxygen-containing gas. An induction furnace is described having a rotating tube and automatic temperature control means.

Abstract: In a sodium sulphur cell, the cathode current collector in the sulphur/polysulphide cathodic reactant comprises a carbon or graphite tube containing a solid metal, e.g. aluminum, core and a liquid metal, e.g. tin or a tin-lead alloy, as a conducting interface between the carbon or graphite tube and the core. In a preferred construction, the current collector is axially located within a cylindrical electrolyte tube, the space between the electrolyte tube and graphite tube containing the sulphur/polysulphides and a graphite felt. The outer surface of the graphite tube in this case may have grooves or recesses to form a sulphur reservoir.

Abstract: In a sodium sulphur cell, the cathode current collector in the sulphur/polysulphide cathodic reactant comprises a carbon or graphite tube containing a solid metal, e.g. aluminum, core and a deformable electronic conductor, e.g. graphite felt, as a conducting interface between the carbon or graphite tube and the core. In a preferred construction, the current collector is axially located within a cylindrical electrolyte tube, the space between the electrolyte tube and graphite tube containing the sulphur/polysulphides and a graphite felt. The outer surface of the graphite tube in this case may have grooves or recesses to form a sulphur reservoir.

Abstract: In making beta-alumina ceramic articles by a fast firing technique in which the green shapes of compressed powder material are sintered by passing them continuously through a tubular furnace, the furnace is sloped upwardly to give convective gas flow forwardly through the furnace at a speed not less than the speed of movement of the article or other means are provided for causing such a gas flow. An induction furnace is described having a rotating tube and automatic temperature control means.

Abstract: In a sodium-sulphur cell having a solid electrolyte and a cathode current collector with a porous conductive matrix, e.g. carbon or graphite felt, in the region between the electrolyte and the current collector, the matrix is formed of a plurality of discrete elements with electronically conductive material, e.g. graphite foil, between the elements extending across the region between the current collector and the electrolyte to increase the conductivity across that region.

Abstract: A thermo-electric generator of the kind making use of beta alumina ceramic through which sodium is circulated to produce an electric potential between the two surfaces of the ceramic has the ceramic in the form of a tube closed at its upper end and with its open end extending into liquid sodium. A heat pipe extends into the ceramic tube and there is an external tubular casing around the ceramic tube forming a closed structure for housing sodium in liquid and vapor form both inside and outside the ceramic tube. The heat pipe may be arranged either as a heat source or heat sink for the sodium inside the ceramic tube, the housing forming the heat sink in the former case of the heat source in the latter. The ceramic tube may, at its open end, be sealed to the housing and a pump used for pumping the sodium from the cold face to the hot face of the ceramic or capillary means may be used to circulate the sodium.

Abstract: In a sodium sulphur cell, the cathode current collector in the sulphur/polysulphide cathodic reactant comprises a carbon or graphite tube containing a solid metal, e.g. aluminium, core and a liquid metal, e.g. tin or a tin-lead alloy, as a conducting interface between the carbon or graphite tube and the core. In a preferred construction, the current collector is axially located within a cylindrical electrolyte tube, the space between the electrolyte tube and graphite tube containing the sulphur/polysulphides and a graphite felt. The outer surface of the graphite tube in this case may have grooves or recesses to form a sulphur reservoir.

Abstract: In an electrochemical cell, such as a sodium-sulphur cell, having a liquid metal electrode and a solid electrolyte, the solid electrolyte is an upright tube with a closed end and a reservoir is provided above the top of the electrolyte tube to accommodate the increased volume of the cathodic reactant as the cell discharges whereby the whole surface of the electrolyte can be in contact with the cathodic reactant despite the increase in volume of the cathodic reactant in the cathodic compartment.

Abstract: Tubes of .beta. alumina ceramic are produced by forming a tube of compressed finely divided powder material, e.g. finely divided crystalline .beta. alumina or finely divided powders which together will form on heating the required ceramic. This tube is passed at a uniform rate through an electric inductive furnace of open-ended tubular form having a short zone at 1600.degree.-1900.degree.C so that the tube is rapidly raised to the sintering temperature and, after a short period in the sintering zone is rapidly cooled.