Abstract: A method is provided for alleviating the stress damage in metallic matrix composites, such as laminated sheet or foil composites, wherein non-intersecting discrete discontinuities are positively introduced into the interface between the layers so as to reduce the thermal stress produced by unequal expansion of the materials making up the composite. The discontinuities are preferably produced by drilling holes in the metallic matrix layer. However, a plurality of discrete elements may be used between the layers to carry out this purpose.

Abstract: A circumferential shaft seal comprising two sealing rings held to a rotating shaft by means of a surrounding elastomeric band. The rings are segmented and are of a rigid sealing material such as carbon or a polyimide and graphite fiber composite.

Abstract: A self-stabilizing radial face seal comprising an axial member, a primary seal ring juxtapositioned to a seal seat, at least one of said primary seal ring and seal seat being affixed to said axial member so as to rotate therewith, said primary seal ring having a front face which opposes a face of said seal seat, said seal having both high-pressure and low-pressure regions of fluid, said seal seat being provided with a porous ring-like circumferential structure in the face of said seal seat opposite said front face of said primary seal ring.

Abstract: The object of the invention is to provide a thermal barrier coating system for protecting metal surfaces at high temperature in normally corrosive environments.The thermal barrier coating system includes a metal alloy bond coating, the alloy containing nickel, cobalt, iron, or a combination of these metals. The system further includes a corrosion resistant thermal barrier oxide coating containing at least one alkaline earth silicate.The preferred oxides are calcium silicate, barium silicate, magnesium silicate, or combinations of these silicates.

Abstract: A method for cold welding metal joints. In order to remove the contamination layer on the surface of the metal, an ion beam generator is used in a vacuum environment. A gas, such as xenon or argon, is ionized and accelerated toward the metal surface. The beam of gas effectively sputters away the surface oxides and contamination layer so that clean underlying metal is exposed in the area to be welded. The use of this method allows cold welding with minimal deformation. Both similar and dissimilar metals can be cold welded with this method.

Abstract: A monolithie multijunction solar cell is modified by fabricating an integrated circuit inverter on the back of the cell to produce a device capable of generating an alternating current output. In another embodiment, integrated circuit power conditioning electronics is incorporated in a module containing a solar cell power supply.

Abstract: A composite material is described which will provide low friction surfaces for materials in rolling or sliding contact and is self-lubricating and oxidation resistant up to and in excess of about 930.degree. C. The composite is comprised of a metal component which lends strength and elasticity to the structure, a fluoride salt component which provides lubrication and, lastly, a glass component which not only provides oxidation protection to the metal but may also enhance the lubrication qualities of the composite.

Abstract: An iron alloy is provided which exhibits excellent strength and toughness characteristics at cryogenic temperatures. The alloy consists essentially of about 10 to 16 percent by weight nickel, about 0.1 to 1.0 percent by weight aluminum, and 0 to about 3 percent by weight copper, with the balance being essentially iron. The iron alloy is produced by a process which includes using cold rolling at room temperature and subsequent heat treatment at temperatures ranging from 400.degree. to 650.degree. C., and possesses a fracture toughness ranging from 200 to 230 ksi .sqroot.in. and yield strengths up to 230 ksi.

Abstract: A circumferential shaft seal comprising two sealing rings held to a rotating shaft by means of a surrounding elastomeric band. The rings are segmented and are of a rigid sealing material such as carbon or a polymide and graphite fiber composite.

Abstract: A method is provided for alleviating the stress damage in metallic matrix composites, such as laminated sheet or foil composites, wherein discontinuities are positively introduced into the interface between the layers so as to reduce the thermal stress produced by unequal expansion of the materials making up the composite. Although a plurality of discrete elements could be used to form one of the layers and thus carry out this purpose, the discontinuities are preferably produced by simply drilling holes in the metallic matrix layer or by forming grooves in a grid pattern in this layer.

Abstract: An electron bombardment argon ion source is used to treat polyimide and fluorinated ethylene propylene polymers to form textured surfaces thereon. This improves the optical and electrical properties so that these polymers can be used in industrial and space applications.

Abstract: A fuel injection system is provided for gas turbines or the like which includes a pair of high pressure pumps which provide fuel and a carrier fluid such as air at pressures above the critical pressure of the fuel. A supercritical mixing chamber mixes the fuel and carrier fluid and the mixture is sprayed into a combustion chamber for burning therein. The use of fuel and a carrier fluid at supercritical pressures promotes rapid mixing of the fuel in the combustion chamber so as to reduce the formation of pollutants and promote cleaner burning.

Abstract: A steel alloy is produced by a process which includes using cold rolling at room temperature and subsequent heat treatment at temperatures ranging from 500.degree. to 650.degree. C.The resulting alloy exhibits excellent strength and toughness characteristics at cryogenic temperatures. This alloy consists essentially of about 10 to 16 percent by weight nickel, to about 1.0 percent by weight aluminum, and 0 to about 3 percent by weight of at least one of the following additional elements: copper, lanthanum, niobium, tantalum, titanium, vanadium, yttrium, zirconium and the rare earth metals, with the balance being essentially iron. The improved alloy possesses a fracture toughness ranging from 200 to 230 ksi.sqroot.in. and yield strengths up to 230 ksi.

Abstract: A seal assembly is provided for reducing the escape of fluids from between a housing and a shaft rotatably mounted in the housing. The seal assembly comprises a pair of seal rings resiliently connected to each other and disposed in side-by-side relationship. In each seal ring, both the internal bore surface and the radial face which faces away from the other seal ring are provided with a plurality of equi-spaced recesses known as Rayleigh step pads. The seal faces referred to are located adjacent a seating surface of the housing. Under normal operating conditions, the seal assembly is stationary with respect to the housing, and the recesses generate lift, keep the assembly spaced from the rotating shaft and allow slip therebetween. Due to expansion of the shaft resulting from rubbing contact with the seal assembly, the seal assembly can seize on the shaft, and slip will then occur between the radial faces and the housing.

Abstract: A solar array-ion thruster system including a power control circuit which provides for use of the thruster itself in operating the solar array at the maximum power point. The power control circuit is connected between the solar array and the ion thruster and receives voltage and current signals from the former. The control circuit multiplies the voltage and current signals together to produce a power signal which is differentiated with respect to time. The differentiator output is detected by a zero crossing detector and, after suitable shaping, the detector output is phase compared with a clock in a phase demodulator. An integrator receives no output from the phase demodulator when the operating point is at the maximum power point but is driven toward the maximum power point for non-optimum operation. A ramp generator provides minor variations in the beam current reference signal produced by the integrator in order to obtain the first derivative of power.

Abstract: A method of making composite material which provides low friction surfaces for materials in rolling or sliding contact. The composite material is self-lubricating and oxidation resistant up to and in excess of about 930.degree. C. The composite material is comprised of a metal component which lends strength and elasticity to the structure, a fluoride salt component which provides oxidation protection to the metal but may also enhance the lubrication qualities of the composite.

Abstract: A heterojunction or Schottky barrier photovoltaic device comprising a conductive base metal layer compatible with and coating predominately the exposed surface of the p-type substrate of the device such that a back surface field region is formed at the interface between the device and the base metal layer, a transparent, conductive mixed metal oxide layer in integral contact with the n-type layer of the heterojunction or Schottky barrier device having a metal alloy grid network of the same metal elements of the oxide constituents of the mixed metal oxide layer embedded in the mixed metal oxide layer, an insulating layer which prevents electrical contact between the conductive metal base layer and the transparent, conductive metal oxide layer, and a metal contact means covering the insulating layer and in intimate contact with the metal grid network embedded in the transparent, conductive oxide layer for conducting electrons generated by the photovoltaic process from the device.

Abstract: A gas path seal suitable for use with a turbine engine or compressor is provided. A shroud wearable or abradable by the abrasion of the rotor blades of the turbine or compressor shrouds the rotor blades. A compliant backing surrounds the shroud. The backing may be made of corrugated sheets or the like with adjacent layers having off-set corrugations, with axes of the folds parallel to the rotor axis. The sheets may be bonded together at points of contact by brazing, welding or the like. In another embodiment a compliant material is covered with a thin ductile layer. A mounting fixture surrounds the backing.

Abstract: A transparent, conductive collector layer containing conductive metal channels is formed as a layer on a photovoltaic substrate by coating a photovoltaic substract with a conductive mixed metal layer; attaching a heat sink having portions protruding from one of its surfaces which define a continuous pattern in combination with recessed regions among said protruding portions to said substrate such that said protruding portions of said heat sink are in contact with the conductive layer of said substrate; andHeating said substrate while simultaneously oxidizing the portions of the conductive layer exposed to a gaseous oxidizing substance forced into said recessed regions of said heat sink, thereby creating a transparent metal oxide layer on said substrate containing a continuous pattern of highly conductive metal channels in said layer.

Abstract: Thermocouples of the present invention provide stability and performance reliability in systems involving high temperatures and vacuums by employing a bimetallic thermocouple sensor wherein each metal of the sensor is selected from a group of metals comprising molybdenum and iridium and alloys containing only those two metals. The molybdenum, iridium thermocouple sensor alloys provide bare metal thermocouple sensors having advantageous vapor pressure compatibilities and performance characteristics. The compatibility and physical characteristics of the thermocouple sensor alloys of the present invention result in improved emf, temperature properties and thermocouple hot junction performance. The thermocouples formed of the molybdenum, iridium alloys exhibit reliability and performance stability in systems involving high temperatures and vacuums and are adaptable to space propulsion and power systems and nuclear environments.