Lunar and planetary surface analysis using neutron activation.
Neutron activation analysis of Si, Fe, Al, Mg and O content of lunar and planetary surfaces
ELEMENT ABUNDANCE↗
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Microchemical surface analysis by electron spectroscopy
Auger electron velocity analyzer for use with scanning electron microscope to identify low concentrations of elements on surfaces of semiconductor devices
Source record↗
Orbital chemistry - Lunar surface analysis from the X-ray and gamma ray remote sensing experiments
The X-ray and gamma-ray lunar surface remote sensing experiments conducted by the Apollo 15 and 16 are discussed. The data indicate mare basins that are extensively basaltic and highlands of aluminum-rich anorthositic-type feldspar. An east-west asymmetry involving higher Al/Si ratios toward the east is noted; high concentrations of a KREEP-type component along the Imbrium-Procellarum edges and throughout the basin are also observed. Lunar K/Th ratios, lowest in areas of the Imbrium and higher in the surrounding mare and highlands, may lend support to the picture of the moon as a high-temperature condensate.
Adler, I.↗
Airspace Technology Demonstration 2 (ATD-2): Simulation and Modeling Used in Surface Analysis
This presentation describes how the fast-time simualtion and modeling techniques are used in the development of ATD-2 system, especially for surface traffic data anlaysis. This presentation will answer the following questions: What analytical results are most important to communicate to Industry from ATD-2 simulation? What fast-time simulations are currently in the works, including EOBT quality impact study and benefits/costs assessment of ATD-2?
fast-time simulation↗
Ellipsometric surface analysis of wear tracks produced by different lubricants
A scanning ellipsometer with high spatial resolution was used to analyze wear tracks generated on M-50 surfaces operated in several lubricant formulations. These formulations included a pure ester base stock of trimethyol propane triheptanoate with additives of either benzotriazole (BTZ), dioctyldiphenylamine (DODPA), or tricresylphosphate (TCP). Results indicated that BTZ and TCP produced patchy oxide surface films consisting mainly of Fe304. DOPDA produced a much more uniform oxide film. These findings may explain the tendency of lubricant formulations containing TCP to scuff more readily than those containing only antioxidants.
Lauer, J. L.↗
Quantitative Hydrocarbon Surface Analysis
The elimination of ozone depleting substances, such as carbon tetrachloride, has resulted in the use of new analytical techniques for cleanliness verification and contamination sampling. The last remaining application at Rocketdyne which required a replacement technique was the quantitative analysis of hydrocarbons by infrared spectrometry. This application, which previously utilized carbon tetrachloride, was successfully modified using the SOC-400, a compact portable FTIR manufactured by Surface Optics Corporation. This instrument can quantitatively measure and identify hydrocarbons from solvent flush of hardware as well as directly analyze the surface of metallic components without the use of ozone depleting chemicals. Several sampling accessories are utilized to perform analysis for various applications.
Douglas, Vonnie M.↗
Preparation and Surface Analysis of a Fluorinated Amorphous Silicon for Photo-voltaic Device Application
Amorphous silicon films (a-Si:H) have been routinely deposited on a variety of substrates. Surface and interfacial studies were carried out with a PHI 5600 X-ray photo electron spectrometer. Co-deposition with fluorine yielded films having oxygen present as bulk oxide. The higher the fluorine content, the greater the amount of bulk oxygen observed. The presence of oxygen may be a contributing factor to inconsistent film properties of fluorine doped silicon materials, reported else where. A definite chemical interface between a layer containing fluorine and a layer made from pure silane has been delineated.
McWhinney, Hylton G.↗
A far-ultraviolet photometer for planetary surface analysis
The measurement of local variations in the far-ultraviolet albedo is explored as a means of detecting changes in the refractive index of rocks and dust on the surface of atmosphereless planets and satellites. Far-ultraviolet spectrophotometric measurements of the lunar surface, which were obtained on the Apollo 17 orbital mission, are presented to demonstrate that significant albedo variations occur in the spectral range 120 to 170 nm. These data also confirm the hypothesis that the albedo variations represent refractive-index differences in the surface materials. A three-band photometer is described which, when put in orbit around a solar system object, is capable of providing refractive-index maps with a sensitivity of one part in the second decimal place and with kilometer resolution. Comparative surface-composition and surface-history analyses based on such maps are discussed.
Henry, R. C.↗
Surface analysis of grapite fiber reinforced polyimide composites. I
The results of experimental analyses of the effects of pretreatment on bonding between composite materials are reported. The materials comprised graphite fibers in a polyimide matrix. The surfaces were bonded as-received or subjected to grit blasting, bead blasting, hand sanding, washes with ethanolic KOH, NH2NH2-H2O or H2SO4 + 0.30 H2O2 or flashblasting. SEM and X-ray photoelectron spectroscopy revealed fluorine contents in the as-received samples. Contact angles were determined by means of five different liquids with various surface tensions. The flashblast technique removed all fluorine from the samples. Low critical surface tensions were found in the composite surfaces with high fluorine concentrations. The surface scanning techniques are concluded to be useful for studying factors influencing the strength and durability of adhesively bonded composites.
Messick, D. L.↗
Surface analysis in composite bonding
The role of the interfacial region in determining the bond strength and durability of composite bonds is discussed. The characterization of a variety of carbon fibers including Celion 6000 using both scanning electron microscopy and X-ray photoelectron spectroscopy is discussed. The emphasis is on composite bonding, that is, the adhesive bonding between composites in contrast to fiber-matrix interaction. The primary objective of the research is the characterization of composite surfaces before adhesive bonding and after fracture of bonded specimens. Work done on the analysis of composite samples pretreated in a number of ways prior to bonding is detailed.
Messick, D. L.↗
A Neutron Activation Gamma Ray spectrometer for Planetary Surface Analysis
A pulsed DT neutron generator system, similar to that used in commercial well logging, offers the possibility of performing accurate elemental analyses to depths of tens of centimeters in a few seconds with the probe on the body's surface.
gamma-ray spectrum neutron pulses spectrometer imp↗
Ellipsometric surface analysis of wear tracks produced by different lubricants
Ellipsometric analyses of wear tracks in berings of M-50 steel were carried out after operation under severe conditions with different lubricant additives. The base lubricant was a synthetic ester. It was found that the surface and wear additives benzotirazole and tricresylyphosphate produced very patchy oxide layers. Dioctyldiphenylamine, a common antioxidant, on the other hand produced smoother films. The analyses were performed with a specially designed and constructed ellipsometer of very high (20 micron) spatial resolution. The results are consistent with data obtained by Auger electron spectroscopy.
Lauer, J. L.↗
Surface Analysis and Tools
This article is a chapter of the book entitled, "Tribology of Mechanical Systems," to be published by ASME Press, New York, NY. It describes selected analytical techniques, which are being used in understanding phenomena and mechanisms of oxidation, adhesion, bonding, friction, erosion, abrasion, and wear, and in defining the problems. The primary emphasis is on microanalytical approaches to engineering surfaces.
Miyoshi, Kazuhisa↗
A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics
The effects of composites as adherends was studied. Several other variables were studied by fractography: aluminum powder adhesive filler, fiber glass cloth scrim or adhesive carrier, new adhesives PPQ-413 and LARC-13, and strength-test temperature. When the new results were juxtaposed with previous work, it appeared that complex interactions between adhesive, adherend, bonding, and testing conditions govern the observed strength and fracture-surface features. The design parameters likely to have a significant effect upon strength-test results are listed.
Dwight, D. W.↗
Fracture surface analysis in composite and titanium bonding: Part 1: Titanium bonding
Fractured lap shear Ti 6-4 adherends bonded with polyphenyquinoxaline (PPQ) and polysulfone were analyzed. The effects of adherend pretreatment, stress level, thermal aging, anodizing voltage, and modified adhesive of Ti 6-4 adherend bonded with PPQ on lap shear strength were studied. The effect of adherend pretreatment on lap shear strength was investigated for PS samples. Results of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) used to study the surface topography and surface composition are also discussed.
Sanderson, K. A.↗
A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics
The ability of SEM/EDAX to determine the physical and chemical composition of very small areas was used to study several diverse types of samples representative of NASA-LaRC technology. More systematic investigation was carried out on differences in the results of grit-blasting Ti 6-4 adherends and the presence of extraneous elements, primarily silicon, in some polymer/HT-S fiber composites. Initial results were obtained from a fractured (ILS) short-beam shear specimen, and from Ti 6-4 alloy, before and after a proprietary Boeing anodizing surface preparation for adhesive bonding. Photomicrographs and EDAX spectra were also obtained from new, fractured lap shear strength specimens that employed PPQ and LARC-13 adhesives.
Dwight, D. W.↗
Surface analysis of space telescope material specimens
Qualitative and quantitative data on Space Telescope materials which were exposed to low Earth orbital atomic oxygen in a controlled experiment during the 41-G (STS-17) mission were obtained utilizing the experimental techniques of Rutherford backscattering (RBS), particle induced X-ray emission (PIXE), and ellipsometry (ELL). The techniques employed were chosen with a view towards appropriateness for the sample in question, after consultation with NASA scientific personnel who provided the material specimens. A group of eight samples and their controls selected by NASA scientists were measured before and after flight. Information reported herein include specimen surface characterization by ellipsometry techniques, a determination of the thickness of the evaporated metal specimens by RBS, and a determination of trace impurity species present on and within the surface by PIXE.
Fromhold, A. T.↗
Fracture surface analysis in composite and titanium bonding
To understand the mechanical properties of fiber-reinforced composite materials, it is necessary to understand the mechanical properties of the matrix materials and of the reinforcing fibers. Another factor that can affect the mechanical properties of a composite material is the interaction between the fiber and the matrix. In general, composites with strong fiber matrix bonding will give higher modulus, lower toughness composites. Composites with weak bonding will have a lower modulus and more ductility. The situation becomes a bit more complex when all possibilities are examined. To be considered are the following: the properties of the surface layer on the fiber, the interactive forces between polymer and matrix, the surface roughness and porosity of the fiber, and the morphology of the matrix polymer at the fiber surface. In practice, the surface of the fibers is treated to enhance the mechanical properties of a composite. These treatments include anodization, acid etching, high temperature oxidation, and plasma oxidation, to name a few. The goal is to be able to predict the surface properties of carbon fibers treated in various ways, and then to relate surface properties to fiber matrix bonding.
Devilbiss, T. A.↗