Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “ion deposition”

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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Properties of coated and modified surfaces

The ability to create surface and near-surface properties distinct from the bulk properties of a material by means of coating or surface modification techniques is an important new field of development for engineering materials, encompassing ion implantation, plasma processing, reactive deposition methods, ion beam deposition and modification, molecular beam epitaxy, and fast quench thermal processing. Attention is given to specific areas of process control which illustrate (1) the use of process development to control material properties, (2) the importance of surface modification and coating to the tribology and ion-surface interactions of semiconductor film growth, and (3) recent findings in surface science which exemplify potential applications of ion-surface interactions that generate novel material qualities.

Mattox, D. M.↗
DOE OSTI2020

GaN/InGaN Blue Light-Emitting Diodes on Polycrystalline Molybdenum Metal Foils by Ion Beam-Assisted Deposition

Light-emitting diode (LED) arrays fabricated on a polycrystalline metal substrate are demonstrated using a novel technique that enables the growth of epitaxial metal-organic chemical vapor deposition (MOCVD) GaN layers on non-single-crystal substrates. Epitaxial GaN is deposited directly on metal foil using an intermediate ion beam-assisted deposition (IBAD) aligned layer. For a single 170 μm-diameter LED on the metal foil, electroluminescence (EL) spectrum shows a peak wavelength of ≈452 nm and a full width at half maximum (FWHM) of ≈24 nm. The current–voltage (I –V ) characteristics show a turn-on voltage of 3.7 V, a series resistance of 10 Ω. LEDs on metal show a relative external quantum efficiency (EQE) that is roughly 3× lower than that of similar LEDs fabricated on a sapphire substrate. Finally, InGaN LEDs on large-area non-single-crystal substrates such as metal foils enable large-area manufacturing, reducing production cost, and opening the door for new applications in lighting and displays.

36 MATERIALS SCIENCE↗
NASA NTRS1994

Friction and Wear Properties of As-deposited and Carbon Ion-implanted Diamond Films

Recent work on the friction and wear properties of as-deposited and carbon ion-implanted diamond films was reviewed. Diamond films were produced by the microwave plasma chemical vapor deposition (CVD) technique. Diamond films with various grain sizes and surface roughnesses were implanted with carbon ions at 60 ke V ion energy, resulting in a dose of 1.2310(exp 17) carbon ions/cm(exp 2). Various analytical techniques, including Raman spectroscopy, proton recoil analysis, Rutherford backscattering, transmission and scanning electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction, were utilized to characterize the diamond films. Sliding friction experiments were conducted with a polished natural diamond pin in contact with diamond films in the three environments: humid air (40 percent relative humidity), dry nitrogen (less than 1 percent relative humidity), and ultrahigh vacuum (10(exp -7) Pa). The CVD diamond films indeed have friction and were properties similar to those of natural diamond in the three environments. The as-deposited, fine-grain diamond films can be effectively used as self-lubricating, wear-resistant coatings that have low coefficients of friction (0.02 to 0.04) and low wear rates (10(exp -7) to 10(exp -8)mm(exp 3)/N-m) in both humid air and dry nitrogen. However, they have high coefficients of friction (1.5 to 1.7) and a high wear rate (10(exp -4)mm(exp 3/N-m) in ultrahigh vacuum. The carbon ion implanation produced a thin surficial layer (less than 0.1 micron thick) of amorphous, nondiamond carbon on the diamond films. In humid air and dry nitrogen, the ion-implanted, fine- and coarse-grain diamond films have a low coefficient of friction (around 0.1) and a low wear rate (10(exp -7)mm(exp 3/N-m). Even in ultrahigh vacuum, the presence of the nondiamond carbon layer reduced the coefficient of friction of fine-grain diamond films to 0.1 or lower and the wear rate to 10(exp -6)mm(exp 3)/N-m. Thus, the carbon ion-implanted, fine-grain diamond films can be effectively used as wear-resistant, self-lubricating coatings not only in air and dry nitrogen, but also in ultrahigh vacuum. The wear mechanism of diamond films is that of small fragments chipping off the surface. The size of wear particles is related to the extent of wear rates.

Miyoshi, Kazuhisa↗
NASA NTRS1996

Friction and Wear Properties of As-Deposited and Carbon Ion-Implanted Diamond Films

Recent work on the friction and wear properties of as-deposited and carbon ion-implanted diamond films was reviewed. Diamond films were produced by the microwave plasma chemical vapor deposition (CVD) technique. Diamond films with various grain sizes and surface roughnesses were implanted with carbon ions at 60 keV ion energy, resulting in a dose of 1.2 x 10(exp 17) carbon ions per cm(exp 2). Various analytical techniques, including Raman spectroscopy, proton recoil analysis, Rutherford backscattering, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, were utilized to characterize the diamond films. Sliding friction experiments were conducted with a polished natural diamond pin in contact with diamond films in the three environments: humid air (40% relative humidity), dry nitrogen (less than 1 percent relative humidity), and ultrahigh vacuum (10(exp -7) Pa). The CVD diamond films indeed have friction and wear properties similar to those of natural diamond in the three environments. The as-deposited, fine-grain diamond films can be effectively used as self-lubricating, wear-resistant coatings that have low coefficients of friction (0.02 to 0.04) and low wear rates (10(exp -7) to lO(exp -8) mm(exp 3) N(exp -1) m(exp -1)) in both humid air and dry nitrogen. However, they have high coefficients of friction (1.5 to 1.7) and a high wear rate (10(exp -4) mm(exp 7) N(exp -1) m(exp -1)) in ultrahigh vacuum. The carbon ion implantation produced a thin surficial layer (less than 0.1 micron thick) of amorphous, non-diamond carbon on the diamond films. In humid air and dry nitrogen, the ion-implanted, fine and coarse-grain diamond films have a low coefficient of friction (around 0.1) and a low wear rate (10(exp -7) mm(exp 3) N(exp -1) m(exp-1)). Even in ultrahigh vacuum, the presence of the non-diamond carbon layer reduced the coefficient of friction of fine-grain diamond films to 0.1 or lower and the wear rate to 10(exp -6) mm(exp 3) N(exp -1) m(exp -1). Thus, the carbon ion-implanted, fine-grain diamond films can be effectively used as wear-resistant, self-lubricating coatings not only in air and dry nitrogen, but also in ultrahigh vacuum.

Miyoshi, Kazuhisa↗
NASA NTRS1981

Vapor phase diamond growth technology

Ion beam deposition chambers used for carbon film generation were designed and constructed. Features of the developed equipment include: (1) carbon ion energies down to approx. 50 eV; (2) in suit surface monitoring with HEED; (3) provision for flooding the surface with ultraviolet radiation; (4) infrared laser heating of substrate; (5) residual gas monitoring; (6) provision for several source gases, including diborane for doping studies; and (7) growth from either hydrocarbon source gases or from carbon/argon arc sources. Various analytical techniques for characterization of from carbon/argon arc sources. Various analytical techniques for characterization of the ion deposited carbon films used to establish the nature of the chemical bonding and crystallographic structure of the films are discussed. These include: H2204/HN03 etch; resistance measurements; hardness tests; Fourier transform infrared spectroscopy; scanning auger microscopy; electron spectroscopy for chemical analysis; electron diffraction and energy dispersive X-ray analysis; electron energy loss spectroscopy; density measurements; secondary ion mass spectroscopy; high energy electron diffraction; and electron spin resonance. Results of the tests are summarized.

Angus, J. C.↗
NASA NTRS1985

Rolling contact fatigue behavior of Cu and TiN coatings on bearing steel substrates

The resistance of copper and TiN coatings on various bearing substrates to high-load rolling contact fatigue (RCF) is investigated. Special attention is given to the lubricating characteristics of copper deposited by ion plating, and the wear resistant characteristics of TiN deposited by ion plating and magnetron sputtering techniques. RCF samples of 440C and AMS 5749 bearing steels were coated. Sputter deposited and ion plated films were on the RCF samples in a range of thickness from about 2000 A to 2 microns. Results showed a marked improvement of the RCF for pure copper tested on 440C, but a degradation for copper on AMS 5749. It is also found that the 2000 A TiN films behave favorably on the 440C and AMS 5749 bearing steels at RCF stress levels of 786 ksi. Scanning electron microscopy, X-ray diffraction, and electron spectroscopy for chemical analysis were used during the investigation.

Hochman, R. F.↗
DOE OSTI2022

Insights into the Crossover Effects in Cells with High‐Nickel Layered Oxide Cathodes and Silicon/Graphite Composite Anodes

Abstract Silicon anodes are regarded as one of the most promising alternatives to graphite (Gr) anodes due to their ultrahigh capacity, abundance, and low cost. Coupling Si‐based anodes with high‐nickel layered oxide cathodes LiNi x Mn y Co 1− x − y O 2 (NMC, x ≥ 0.8) can enhance the driving range for electric vehicles. Transition‐metal (TM) ion dissolution and deposition has been a long‐known failure mode for Gr‐based lithium‐ion batteries. However, the mechanistic insight associated with TM ion deposition on Si‐based anodes has rarely been reported. Herein, the impact of in situ deposited TM ions on SiO x /Gr composite anodes and the individual influences of Ni, Mn, and Co on the structural and electrochemical stability along with the underlying degradation mechanisms are presented. TM ion dissolution causes a greater deleterious impact on Si than on Gr, with different TM ions exhibiting different influences on anode‐electrolyte interphase formation. Specifically, Ni deposit induces more aggressive salt decomposition; Co deposit has negligible effect on salt decomposition, but significantly accelerates solvent decomposition; and Mn deposit aggravates both salt and solvent decompositions, resulting in worse full cell performance. The extent of degradation decreases in the order Mn 2+ > Ni 2+ > Co 2+ . The systematic comparisons presented can guide further development of high energy systems.

Zhang, Xianhui↗
NASA NTRS1985

Ion beam sputter-deposited thin film coatings for protection of spacecraft polymers in low Earth orbit

Ion beam sputter-deposited thin films of Al2O3, SiO2, and a codeposited mixture of predominantly SiO2 with small amounts of a fluoropolymer were evaluated both in laboratory plasma ashing tests and in space on board shuttle flight STS-8 for effectiveness in preventing oxidation of polyimide Kapton. Measurements of mass loss and optical performance of coated and uncoated polyimide samples exposed to the low Earth orbital environment are presented. Optical techniques were used to measure loss rates of protective films exposed to atomic oxygen. Results of the analysis of the space flight exposed samples indicate that thin film metal oxide coatings are very effective in protecting the polyimide. Metal oxide coatings with a small amount of fluoropolymer codeposited have the additional benefit of great flexibility.

Banks, B. A.↗
NASA NTRS1985

Ion beam sputter-deposited thin film coatings for protection of spacecraft polymers in low earth orbit

Ion beam sputter-deposited thin films at Al2O3, SiO2, and a codeposited mixture of predominantly SiO2 with small amounts of fluoropolymer were evaluated both in laboratory plasma ashing tests and in space on board Shuttle flight STS-8 for effectiveness in preventing oxidation of polyimide Kapton. Measurements of mass loss and optical performance of coated and uncoated polyimide samples exposed to the low earth orbital environment are presented. Optical techniques were used to measure loss rates of protective films exposed to atomic oxygen. Results of the analysis of the space flight exposed samples indicate that thin film metal oxide coatings are very effective in protecting the polyimide. Metal oxide coatings with a small amount of fluoropolymer codeposited have the additional benefit of great flexibility.

Banks, B. A.↗
NASA NTRS1998

Fluoropolymer Films Deposited by Argon Ion-Beam Sputtering of Polytetrafluoroethylene

The FT-IR, XPS and UV spectra of fluoropolymer films (SPTFE-I) deposited by argon ion-beam sputtering of polytetrafluoroethylene (PTFE) were obtained and compared with prior corresponding spectra of fluoropolymer films (SPTFE-P) deposited by argon rf plasma sputtering of PTFE. Although the F/C ratios for SPTFE-I and -P (1.63 and 1.51) were similar, their structures were quite different in that there was a much higher concentration of CF2 groups in SPTFE-I than in SPTFE-P, ca. 61 and 33% of the total carbon contents, respectively. The FT-IR spectra reflect that difference, that for SPTFE-I showing a distinct doublet at 1210 and 1150 per centimeter while that for SPTFE-P presents a broad, featureless band at ca. 1250 per centimeter. The absorbance of the 1210-per centimeter band in SPTFE-I was proportional to the thickness of the film, in the range of 50-400 nanometers. The SPTFE-I was more transparent in the UV than SPTFE-P at comparable thickness. The mechanism for SPTFE-I formation likely involves "chopping off" of oligomeric segments of PTFE as an accompaniment to "plasma" polymerization of TFE monomer or other fluorocarbon fragments generated in situ from PTFE on impact with energetic Ar ions. Data are presented for SPTFE-I deposits and the associated Ar(+) bombarded PTFE targets where a fresh target was used for each run or a single target was used for a sequence of runs.

Golub, Morton A.↗
NASA NTRS1993

Optical and scratch resistant properties of diamondlike carbon films deposited with single and dual ion beams

Amorphous diamondlike carbon (DLC) films were deposited using both single and dual ion beam techniques utilizing filament and hollow cathode ion sources. Continuous DLC films up to 3000 A thick were deposited on fused quartz plates. Ion beam process parameters were varied in an effort to create hard, clear films. Total DLC film absorption over visible wavelengths was obtained using a Perkin-Elmer spectrophotometer. An ellipsometer, with an Ar-He laser (wavelength 6328 A) was used to determine index of refraction for the DLC films. Scratch resistance and frictional and adherence properties were determined for select films. Applications for these films range from military to the ophthalmic industries.

Kussmaul, Michael T.↗
NASA NTRS1978

Ion beam sputter etching and deposition of fluoropolymers

Fluoropolymer etching and deposition techniques including thermal evaporation, RF sputtering, plasma polymerization, and ion beam sputtering are reviewed. Etching and deposition mechanism and material characteristics are discussed. Ion beam sputter etch rates for polytetrafluoroethylene (PTFE) were determined as a function of ion energy, current density and ion beam power density. Peel strengths were measured for epoxy bonds to various ion beam sputtered fluoropolymers. Coefficients of static and dynamic friction were measured for fluoropolymers deposited from ion bombarded PTFE.

Banks, B. A.↗
NASA NTRS1978

Ion beam sputter etching and deposition of fluoropolymers

Fluoropolymer etching and deposition techniques including thermal evaporation, RF sputtering, plasma polymerization, and ion beam sputtering are reviewed. Etching and deposition mechanisms and material characteristics are discussed. Ion beam sputter etch rates for polytetrafluoroethylene (PTFE) were determined as a function of ion energy, current density and ion beam power density. Peel strengths were measured for epoxy bonds to various ion beam sputtered fluoropolymers. Coefficients of static and dynamic friction were measured for fluoropolymers deposited from ion bombarded PTFE.

Banks, B. A.↗
DOE OSTI2023

The dependence of tungsten fuzz layer thickness and porosity on tungsten deposition rate and helium ion fluence

Abstract Fuzz formation on a heated tungsten surface in the presence of a helium-containing plasma and tungsten deposition source was investigated. Tungsten samples were exposed at 1123 K to pure helium plasma with ion incident energy of 76 eV, W/He ion flux ratio of ∼ 0.4 × 10 − 4 , and varied helium ion fluence from 0.18 to 3.4 × 10 26 m −2 . Fuzz thickness was measured by cross-sectional scanning electron microscopy to increase from 0.22 to 15 µ m with increasing helium ion fluence. No indication of saturation in fuzz thickness at high fluence was observed, in contrast to fuzz produced on a tungsten surface without tungsten deposition. Additional tungsten samples were exposed at 1123 K to pure helium plasma with ion incident energy of 76 eV, helium ion fluence of ∼ 3.4 × 10 26 m −2 , and varied W/He ion flux ratio from 0.26 to 3.0 × 10 − 4 . Fuzz thickness increased from 7.5 to 120 µ m with increasing W/He ion ratio. A final sample exposed at 1123 K to a mixed helium-deuterium plasma with ion incident energy of 76 eV, helium ion fluence of 0.18 × 10 26 m −2 , and W/He ion flux ratio of 2.2 × 10 − 4 developed nearly identical fuzz structures to that developed in a pure He plasma. As a function of deposited tungsten fluence, all results were found to trace out a single layer-growth curve given by a power law relation, indicating that fuzz thickness is independent of the W/He ion flux ratio in the range investigated and independent of any deuterium present in the plasma. As a result, for tungsten plasma facing walls in magnetic fusion devices at 1000–2000 K with 10 −4 W/He ion flux ratio, fuzz with thicknesses greater than hundreds of microns may form in as little as 10 4 s (in the absence of ELM-induced erosion or annealing), and may more significantly affect its thermophysical properties than fuzz generated without a tungsten deposition source.

Physics↗
NASA NTRS1993

Optical and Scratch Resistant Properties of Diamondlike Carbon Films Deposited with Single and Dual Ion Beams

Amorphous diamond-like carbon (DLC) films were deposited using both single and dual ion beam techniques utilizing filament and hollow cathode ion sources. Continuous DLC films up to 3000 A thick were deposited on fused quartz plates. Ion beam process parameters were varied in an effort to create hard, clear films. Total DLC film absorption over visible wavelengths was obtained using a Perkin-Elmer spectrophotometer. An ellipsometer, with an Ar-He laser (wavelength 6328 A) was used to determine index of refraction for the DLC films. Scratch resistance, frictional, and adherence properties were determined for select films. Applications for these films range from military to the ophthalmic industries.

Kussmaul, Michael T.↗
DOE OSTI2020

Temperature and processing effects on lithium ion conductivity of solution‐deposited lithium zirconium phosphate (LiZr 2 P 3 O 12 ) thin films

Abstract Lithium zirconium phosphate (LiZr 2 P 3 O 12 ) thin films have been prepared on platinized silicon substrates via a chemical solution deposition approach with processing temperatures between 700°C and 775°C. Films that were subject to a single high‐temperature anneal were found to crystallize at temperatures above 725°C. Crystallization was observed in films annealed after each deposited layer at 700°C and above. In both cases, grain size was found to increase with annealing temperature. Ion conductivity was found to increase with annealing temperature in singly annealed films. In per‐layer annealed films ion conductivity was found to initially increase then decrease with increasing annealing temperature. A maximum ion conductivity of 1.6 × 10 −6 S/cm was observed for the singly annealed 775°C condition, while a maximum ion conductivity of 5.8 × 10 −7 S/cm was observed for the 725°C per‐layer annealed condition. These results are consistent with an increasing influence of cross‐plane, internal interface resistance and vapor phase carrier loss in the per‐layer annealed samples. This work demonstrates that post‐deposition processing methods can strongly affect the ion conducting properties of LiZr 2 P 3 O 12 thin films.

Brummel, Ian A.↗