Search NASA⌕ Search

SEARCH · Search NASA

Results for “Surface Analysis”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics

The acid-base properties of titanium 6-4 plates (low surface area) were investigated after three different pretreatments, namely Turco, phosphate-fluoride and Pasa-Jell. A series of indicators was used and color changes were detected using diffuse reflectance visible spectroscopy. Electron spectroscopy for chemical analysis was used to examine the indicator on the Ti 6-4 surface. Specular reflectance infra-red spectroscopy was used to study the adsorption of stearic acid from cyclohexane solutions on the Ti 6-4 surface.

Siriwardane, R.↗
NASA NTRS1983

Surface analysis of graphite fiber reinforced polyimide composites

Several techniques have been used to establish the effect of different surface pretreatments on graphite-polyimide composites. Composites were prepared from Celion 6000 graphite fibers and the polyimide LARC-160. Pretreatments included mechanical abrasion, chemical etching and light irradiation. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used in the analysis. Contact angle of five different liquids of varying surface tensions were measured on the composites. SEM results showed polymer-rich peaks and polymer-poor valleys conforming to the pattern of the release cloth used durng fabrication. Mechanically treated and light irradiated samples showed varying degrees of polymer peak removal, with some degradation down to the graphite fibers. Minimal changes in surface topography were observed on concentrations of surface fluorine even after pretreatment. The light irradiation pretreatment was most effective at reducing surface fluorine concentrations whereas chemical pretreatment was the least effective. Critical surface tensions correlated directly with the surface fluorine to carbon ratios as calculated from XPS.

Messick, D. L.↗
NASA NTRS1986

Fracture surface analysis in composite and titanium bonding

Carbon fibers were obtained from several manufacturers. Surface treatments were performed on these fibers by anodization. The surfaces of these fibers were analyzed by X-ray photoelectron spectroscopy and wetting force measurement. The breaking strength of these fibers was measured at 2.5 cm length. It was seen that the surface treatments reduces the strength of the fibers. It was also seen that the Hercules fibers had a higher breaking strength than the Union Carbide fibers. Fiber critical length measurements showed no difference in critical lengths between AS-4 and AU-4 fibers embedded in polysulfone. However, the fiber lengths were much shorter for the surface treated fibers. This effect could be related to increased adhesion between fiber and matrix, or it could be due to the lower breaking strength of the surface treated fiber.

Devilbiss, T. A.↗
NASA NTRS1993

Near surface analysis

This is a study to assist in the understanding of earth near surface structure. Higher order moments are used to detect the density distribution as well as to seek patterns found in geological structures. It is shown how higher order moments at points outside a mass structure are determined as well as how to recover the mass distribution from the higher order moments. It is interesting to note that the first moment at a point P outside the mass structure, V(sub O)(P), is the entire mass and the second moment, V(sub 1)(P), is the potential at P due to the mass structure. Usually only the mass and the potential function are used to determine the density distribution in a body. An infinite function sequence (V(sub n)(P))(sub n=0)(sup infinity) is required to uniquely determine the density distribution.

Johnson, Gordon G.↗
NASA NTRS1996

Surface Analysis of LDEF Materials

The abstract to the M.S. thesis included as appendix to this report contains the details of the research performed under this grant. Presentations and publications resulting from the research are listed as the main content of the report itself. The thesis describes the surface characterization procedures and analysis of materials flown in the NASA Long Duration Exposure Facility (LDEF).

Wightman, J. P.↗
NASA NTRS1997

Raman Spectroscopy for Mineral Identification and Quantification for in situ Planetary Surface Analysis: A Point Count Method

Quantification of mineral proportions in rocks and soils by Raman spectroscopy on a planetary surface is best done by taking many narrow-beam spectra from different locations on the rock or soil, with each spectrum yielding peaks from only one or two minerals. The proportion of each mineral in the rock or soil can then be determined from the fraction of the spectra that contain its peaks, in analogy with the standard petrographic technique of point counting. The method can also be used for nondestructive laboratory characterization of rock samples. Although Raman peaks for different minerals seldom overlap each other, it is impractical to obtain proportions of constituent minerals by Raman spectroscopy through analysis of peak intensities in a spectrum obtained by broad-beam sensing of a representative area of the target material. That is because the Raman signal strength produced by a mineral in a rock or soil is not related in a simple way through the Raman scattering cross section of that mineral to its proportion in the rock, and the signal-to-noise ratio of a Raman spectrum is poor when a sample is stimulated by a low-power laser beam of broad diameter. Results obtained by the Raman point-count method are demonstrated for a lunar thin section (14161,7062) and a rock fragment (15273,7039). Major minerals (plagioclase and pyroxene), minor minerals (cristobalite and K-feldspar), and accessory minerals (whitlockite, apatite, and baddeleyite) were easily identified. Identification of the rock types, KREEP basalt or melt rock, from the 100-location spectra was straightforward.

Haskin, Larry A.↗
DOE OSTI2021

Towards a reliable assessment of charging effects during surface analysis: Accurate spectral shapes of ZrO 2 and Pd/ZrO 2 via X-ray Photoelectron Spectroscopy

X-ray Photoelectron Spectroscopy of large bandgap or insulating material surfaces relies on an effective mechanism that compensates for the emission (loss) of electrons by maintaining the material surface at a steady-state uniform potential. While a steady-state may be attained by utilizing an active compensation, such as low power electron emitting filament, there is the possibility that the surface potential is not uniform over the area analyzed, leading to peak shifts and incorrect spectral interpretation. Here, in this work, a spectral data processing method based on mapping the ZrO 2 and Pd/ZrO 2 surfaces utilizing photoemission peak binding energy is proposed, which provides information about the response of specific material surfaces to charge compensation. Spectromicroscopy of ZrO 2 and Pd/ZrO 2 surfaces without spatial information is used to monitor the efficacy of charge compensation. Exploiting counts distributed over many bins require the use of procedures and algorithms essential to practical mapping peak positions. Iterative singular value decomposition is therefore introduced and utilized as a means of efficiently delivering spatially resolved spectra from which binding energy for peaks is computed. The concepts developed in this work result in robust and accurate peak models of ZrO 2 and Pd/ZrO 2 that can be applied in XPS analysis of not only ZrO 2 but other large bandgap or insulating material surfaces. Supporting arguments for a peak model representing signal from Zr 3p and Pd 3d are developed within this work are presented.

36 MATERIALS SCIENCE↗
NASA NTRS1977

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.↗
NASA NTRS2019

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↗
NASA NTRS1985

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.↗
NASA NTRS2000

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.↗
NASA NTRS1998

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.↗
NASA NTRS1976

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.↗
NASA NTRS1983

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.↗
NASA NTRS1982

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.↗