Abstract: A high voltage multijunction solar cell comprises a plurality of discrete voltage generating regions, or unit cells, which are formed in a single semiconductor wafer (10) and are connected together so that the voltages of the individual cells are additive. The unit cells comprise doped regions of opposite conductivity types (30, 32) separated by a gap. The method includes forming V-shaped grooves (16) in the wafer and thereafter orienting the wafer so that ions of one conductivity type can be implanted in one face (e.g., 16a) of the groove while the other face (e.g., 16b) is shielded. A metallization layer (22) is applied and selectively etched away to provide connections between the unit cells.

Abstract: A low cost coating protects metallic base system substrates from high temperatures, high gas velocity ovidation, thermal fatigue and hot corrosion. The coating is particularly useful for protecting vanes and blades in aircraft and land based gas turbine engines.A lacquer slurry comprising cellulose nitrate containing high purity silicon powder is sprayed onto the superalloy substrates. The silicon layer is then aluminized to complete the coating.The Si-Al coating is less costly to produce than advanced aluminides and protects the substrate from oxidation and thermal fatigue for a much longer period of time than the conventional aluminide coatings. While more expensive Pt-Al coatings and physical vapor desposited MCrAlY coatings may last longer or provide equal protection on certain substrates, the Si-Al coating exceeded the performance of both types of coatings on certain superalloys in high gas velocity oxidation and thermal fatigue.

Abstract: This invention is concerned with improving the efficiency of thermionic energy converters. The invention is particularly directed to the reduction of plasma losses in these converters.This beneficial technical effect is achieved by internal distribution of tiny shorted cesium diodes driven by the thermal gradient between the primary emitter (10) and the collector (12). Specifically, the tiny, shorted diode distribution (14) comprises protrusions of the emitter material (16) from the main emitter face (18) which contact the main collector face (22) thermally but not electrically. The main collector ends (20) of the protrusions are separated from the main collector by a thin layer of insulation (24), such as aluminum oxide.The diode effect will increase with the use of metals that adsorb cesium less readily for the main emitter ends of the tiny protrusions and metals that adsorb cesium more readily for the main collector ends of the protrusions.

Abstract: This invention is concerned with improving high temperature evaporation-condensation heat-transfer devices which have important and unique advantage in terrestrial and space energy 5 processing. The device is in the form of a heat pipe 10 comprising a sealed container or envelope 12 which contains a capillary wick 14.The temperature of one end of the heat pipe is raised by the input of heat from an external heat source 16 which is extremely hot and corrosive. A working fluid 18 of a corrosive alkali metal, such as lithium, sodium, or potassium transfers this heat to a heat receiver 20 remote from the heat source.In accordance with the invention the container 12 and wick 14 are fabricated from a superalloy containing a small percentage of a corrosion inhibiting or gettering element. Lanthanum, scandium, yttrium, thorium, and hafnium are utilized as the alloying metal.