The degradation of Cu2S-CdS thin film solar cells under simulated orbital conditions
Copper disulfide-cadmium sulfide thin film solar cell degradation under simulated low orbit conditions, investigating thermal stress
Bernatowicz, D. T.↗
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Photovoltaic properties of Cu2S-CdS heterojunctions
Heat treatment and photovoltaic properties of copper disulfide-cadmium sulfide heterojunctions, measuring I-V characteristics, capacitance and spectral response
Bube, R. H.↗
Friction torque of ball bearings with burnished MoS2 films at .1 nanotorr at several loads using five retainer materials
Determination of bearing torque for burnished molybdenum disulfide ball bearings
Anderson, W. J.↗
Absorption spectrum of CS2 in the region from 600 to 1015 A
Carbon disulfide absorption spectrum measurement in far UV region
Chang, H. C.↗
The degradation of Cu2S-CdS thin film solar cells under simulated orbital conditions
Copper sulfide-cadmium disulfide thin film solar cells degradation under simulated orbital conditions, determining electrochemically induced copper filament growth as electric shorts causes
Bernatowicz, D. T.↗
Identity of a common contaminant of Apollo 11 lunar fines and Apollo 12 York meshes
Apollo 11 and 12 lunar soil samples common contaminant identified as diisopropyl disulfide, using chromatograph mass spectrometer
Flory, D.↗
Sliding-load history effects on the friction of MoS2 in vacuum
Sliding load history effects on friction of thin burnished films of molybdenum disulfide in vacuum
Jamison, W. E.↗
Radiofrequency-sputtered coatings for lubrication system components and other complex surfaces
Irregularly shaped surfaces, such as lubrication system components (ball bearings, seals, gears, etc.), can be coated on all surfaces, including irregular shapes, when radiofrequency sputtering is used. When the specimen is properly located with respect to the sputtering target, the sputtered material covers the entire surface of the object irrespective of its geometrical configuration. An adherent, dense film is formed. The film thickness varies from 20 to 50 percent on, for example, a hearing cage or race depending on its geometry. When sputtered solid film lubricants such as molybdenum disulfide are used, a film thickness only of the order of 10 to the minus 7th power m (thousands of angstroms) is required at the contacting areas. It is only essential to determine the required film thickness at the critical areas in need of lubrication. The sections outside the areas to be lubricated fall within the thickness deviation range of 20 to 50 percent, which still constitutes a negligible change respect to tolerance requirements.
Spalvins, T.↗
Dynamic friction and wear of a solid film lubricant during radiation exposure in a nuclear reactor
The effect of nuclear reactor radiation on the performance of a solid film lubricant was studied. The film consisted of molybdenum disulfide and graphite in a sodium silicate binder. Radiation levels of fast neutrons (E or = 1 MeV) were fluxed up to 3.5 times 10 to the 12th power n/sq cm-sec (intensity) and fluences up to 2 times 10 to the 18th power n/sq cm (total exposure). Coating wear lives were much shorter and friction coefficients higher in a high flux region of the reactor than in a low flux region. The amount of total exposure did not affect lubrication behavior as severely as the radiation intensity during sliding.
Jacobson, T. P.↗
The synergistic effects of slip ring-brush design and materials
The design, fabrication, and testing of four power slip rings for synchronous orbit application are considered. Environmental and instrumentation systems necessary for monitoring electrical noise, friction, and brush wear in air and at less than 5 X 10 to the minus 8th power torr were developed. Composite brushes consisting of silver-molybdenum disulfide-graphite and silver-niobium diselenide-graphite were employed on rings of coin silver and rhodium plate. These four contact combinations were tested during ambient condition run-in at 150 and a humidity sequence at 0.1. The first nine months of a two year vacuum test performed at 0.1 rpm were completed.
Lewis, N. E.↗
Friction, wear and noise of slip ring and brush contacts for synchronous satellite use.
A program is being conducted for testing of slip rings for synchronous orbit application. Instrumentation systems necessary for monitoring electrical noise, friction, and brush wear at atmospheric pressure and at less than 50 ntorr have been developed. A multiplex scheme necessary for the simultaneous recording of brush displacement, friction, and electrical noise has also been developed. Composite brushes consisting of silver-molybdenum disulfide-graphite and silver-niobium diselenide-graphite have been employed on rings of coin silver and rhodium plate. Four contact combinations have been tested during an ambient condition run-in at 150 rpm and a humidity sequence at 0.1 rpm. The first six months of the two year vacuum test at 0.1 rpm have been completed. Electrical noise, friction and brush wear data recorded during these periods have been analyzed.
Lewis, N. E.↗
Evidence of crystal structure in some sputtered MoS2 films.
Electron diffraction patterns and electron micrographs of molybdenum disulfide films sputtered on single-NaCl-crystal and electropolished-aluminum substrates are presented as evidence that crystalline MoS2 films can be sputtered onto various substrates in thicknesses up to 2 microns. Applied to Falex test pins and V-blocks, some of these films exhibited a wear life as long as 65 minutes at 1000 lb jaw load.
Lavik, M. T.↗
Friction, wear, and noise of slip ring and brush contacts for synchronous satellite use.
A program is being conducted for testing of slip rings for synchronous orbit application. Instrumentation systems necessary for monitoring electrical noise, friction, and brush wear at atmospheric pressure and at less than 50 nanotorr have been developed. A multiplex scheme necessary for the simultaneous recording of brush displacement, friction, and electrical noise has also been developed. Composite brushes consisting of silver-molybdenum disulfide-graphite and silver-niobium diselenide-graphite have been employed on rings of coin silver and rhodium plate. Brush property measurements made included measurement of density, electrical resistivity, shear strength, and microstructure.
Lewis, N. E.↗
Effect of strain hardening on friction behavior of iron lubricated with benzyl structures
Sliding friction experiments were conducted with iron, copper, and aluminum in contact with iron in various states of strain. The surfaces were examined in dry sliding and with various benzyl compounds applied as lubricants. Friction experiments were conducted with a hemispherical rider contacting a flat disk at loads of from 50 to 600 grams with a sliding speed of 0.15 cm/min. Results indicate that straining increases friction for dry sliding and for surfaces lubricated with certain benzyl structures such as dibenzyl disulfide. With other benzyl compounds (e.g., benzyl formate), friction coefficients are lower for strained than for annealed iron.
Buckley, D. H.↗
Testing and evaluation of solid lubricants for gas bearings
The testing and results of testing solid film lubricants for gas lubricated bearing applications are reported. The tests simulated operational hazards of tilting pad gas bearings. The presence of a low coefficient of friction and the endurance of the solid film lubricant were the criteria for judging superior performance. All solid lubricants tested were applied to a plasma sprayed chrome oxide surface. Molybdenum disulfide and graphite fluoride were the solid lubricants tested; other test parameters included the method of application of the solid lubricant and the surface finish of the plasma sprayed coating. In general, the application of a solid film lubricant was found to significantly improve the coefficient of friction of the rubbing surfaces.
Albrecht, P. R.↗
Start-stop testing of two self-acting air-lubricated spiral groove thrust bearing coatings
Start-stop tests were conducted on air-lubricated spiral-groove thrust bearings. Application of a matrix-bonded molybdenum disulfide (MoS2) coating over a porous chrome oxide coating resulted in significantly lower friction, compared to bearings coated with chrome oxide only. The MoS2 coated bearing sustained 15,000 start-stop cycles at a maximum of 3600 rpm. Each cycle was 15 seconds on, 30 seconds off. The chrome oxide coated bearing failed by local welding after 2030 cycles. Both types of coatings exhibited early failures under higher thrust loads when operating films were insufficient to sustain the load without overheating.
Dunfee, J. D.↗
Effect of crosslinking density on biaxial relaxation of SBR by using reduced variables
The use of reduced variables to account for the effect of crosslinking density in a styrene-butadiene rubber (SBR) system is demonstrated for general biaxial stress states. Recently published results from stress relaxation tests on five SBR vulcanizates crosslinked to different degrees by tetramethylthiuram disulfide were superposed by using the crosslinking density as a reduction variable. The equilibrium shear modulus calculated from the master relaxation curve at long reduced times was in satisfactory agreement with other results for SBR. The time-axis shifts were related in a linear logarithmic manner to the crosslinking density but had a slope slightly less than values previously reported for elastomer systems.
Arenz, R. J.↗
Simplified explosive-weld evaluation
Weld surfaces, coated with commercially available molybdenum disulfide, allow visual inspection of significant indications of bond quality. Process reduces number of trial welds, making explosive bonding more competitive.
Mclarty, D. M.↗