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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Solar absorptance and emittance of candidate zinc oxides/silicone and zinc oxide/potassium silicate coatings measured at room temperature for application to space radiators
High purity silica reinforced ablative composite materials evaluated as nozzle sections of throat storable propellant rocket engine - erosion rates and charring
Feasibility of machine sewing wire reinforced asbestos and silica cloth plies of flexible heat shield curtain assembly
Rapid thermal cycling of integral coverslipped solar cells, and tests on high vacuum sputtered silicon dioxide cells
Fabrication processes for thick integral coverslips for silicon solar cells
Material property effects on ablative performance of silica phenolic, graphite phenolic, and graphite epoxy materials
Optical transmittance of fused silica at elevated temperatures, showing shift in UV to IR ABSORPTION with increasing temperature
Electron beam evaporation of silicon dioxide producing storage layers for automatic picture transmission vidicon, analyzing causes of signal loss after short operating time in flight tubes
Destructive breakdown conduction in aluminum- silicon oxide-aluminum capacitors, discussing voltage threshold, etc
Mass spectrometric analysis of electrolyte degradation during electrolysis in sulfuric acid silica gel cell for oxygen recovery
Adsorption equilibrium data obtained at high pressure for methane and propane on silica gel using radioactive tracer pulsing
A thermodynamic study of the thermal stability of conventional terrestrial minerals in a hypothetical lunar atmosphere has opened some interesting speculation. Much of the Earth's crust is composed of oxides of silicon, aluminum, magnesium, and related compounds. These crust components may be as much a product of the Earth's atmosphere as vegetation and animal life. Though inanimate and long considered imperishable, these materials are stable under conditions of an atmosphere equivalent to 34 ft of water at sea level and persist under adverse conditions of moisture and temperature to altitudes of roughly 29,000 ft above sea level. The oxygen content averages 21% ) and the oxygen partial pressure would be roughly 1/5 atm.
Effective binary diffusion coefficients for multicomponent diffusion determined for potassium oxide and SrO in system potassium oxide-SrO- silicon dioxide
The behavior theory of the light-sensitive MNOS memory transistor is developed and supported by presented experimental evidence. It is shown that the nitride, oxide, and silicon space-charge current-field relationships necessary for comparison of theory and experiment can be obtained from steady-state current-voltage measurements on the MNOS device.
The interdiffusion of platimum and gold films, a couple utilized in beam lead microcircuits, has been studied for temperatures up to 550 C. Gold-on-platinum couples and separate platimum and gold films 80-450 nm thick, were deposited by electron beam evaporation onto oxidized (111) silicon substrates. Diffusion was monitored by means of spectral reflectance versus wavelength in the band 500-1000 nm. The separate metal films showed good adhesion and stable reflectances (after an initial change) for at least 6 h at diffusion temperatures, in contrast to the couples. Analysis of platinum diffusion through the gold films yielded an activation energy about 38 kcal/g-atom and a pre-exponential factor of the order 0.001 sq cm/sec, values close to those for volume diffusion. The pre-exponential factor especially is dependent upon film deposition conditions.
A program was conducted to develop and test electrically conductive paint coatings for spacecraft. A wide variety of organic and inorganic coatings were formulated using conductive binders, conductive pigments, and similar approaches. Z-93, IITRI's standard specification inorganic thermal control coating, exhibits good electrical properties and is a very space-stable coating system. Several coatings based on a conductive pigment (antimony-doped tin oxide) in silicone and silicate binders offer considerable promise. Paint systems using commercially available conductive polymers also appear to be of interest, but will require substantial development. Evaluations were made based on electrical conductivity, paint physical properties, and the stability of spectral reflectance in space environment testing.
The oxidation and corrosion behavior of SiC (in the form of a SiC powder) and hot-pressed and reaction-bound material were studied. The excellent stability of SiC in an oxidizing atmosphere is due to the development of protective SiO2 coatings. Any changes in these protective layers (e.g., due to impurities, reaction with corrosive media, high porosity of SiC, etc.) lead in most cases to increased rates of oxidation and thus restrict the field of SiC application.
The friction properties of some ferrous-base metallic glasses were measured both in argon and in vacuum to a temperature of 350 C. The alloy surfaces were also analyzed with X-ray photoelectron spectroscopy to identify the compounds and elements present on the surface. The results of the investigation indicate that even when the surfaces of the amorphous alloys, or metallic glasses, are atomically clean, bulk contaminants such as boric oxide and silicon dioxide diffuse to the surfaces. Friction measurements in both argon and vacuum indicate that the alloys exhibit higher coefficients of friction in the crystalline state than they do in the amorphous state.