| Solution Deposition Methods for Carbon Nanotube Field-Effect Transistors |
Jun-2009 |
32 pages |
| Authors:
Matthew Ervin; Natalie Salaets; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
 | This study evaluated different methods for controlled deposition of carbon nanotubes (CNTs) from solution onto a silicon substrate to make CNT field-effect transistors (FETs). The goal of this deposition was to achieve reproducible device properties through more uniform CNT densities and other traits. This method serves as an easier, room temperature alternative to chemical vapor deposition growth. Three different types of CNT solutions were spun onto substrates: pristine tubes solubilized ... |
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| Novel MEMS Apparatus for In Situ Thermo-Mechanical Tensile Testing of Materials at the Micro- and Nano-Scale (Preprint) |
Apr-2009 |
6 pages |
| Authors:
M D Uchic; J Han; T Saif; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| We present, for the first time, a MEMS-based test methodology that potentially enables elevated-temperature mechanical tensile testing of nano- and micro-scale samples within a SEM or TEM (T 500 degrees C). Importantly, the test methodology allows for the samples to be fabricated separately from the MEMS-apparatus, a significant advancement from other test devices developed by some of the present authors. Therefore the test methodology should be applicable to the study ... |
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| A Combined Experimental and Computational Study to Examine Lateral Constraint Effects on Single-Slip Oriented Microcompression Experiments (Preprint) |
Apr-2009 |
18 pages |
| Authors:
H L Fraser; M D Uchic; D M Dimiduk; P A Shade; R Wheeler; Y S Choi; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| A custom in-situ SEM mechanical testing system has been used to study the compressive deformation behavior of single-slip oriented Rene N5 microcrystals. Two different compression platens were used to explore the effect of lateral stiffness on the resultant mechanical response, which approximated either a full-frictional or zero-friction case. The change in the lateral constraint of the test system had a demonstrable effect on many aspects or attributes of plastic flow: ... |
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| Effect of Projectile Type, Size and Impact Velocity on Ballistic Impact Failure Behavior of TROGAMID CX-7323 Nylon |
Dec-2008 |
8 pages |
| Authors:
Nicholas Tsantinis; John W Song; ARMY NATICK SOLDIER RESEARCH DEVELOPMENT AND ENGINEERING CENTER MA
|
| Extensive study on the fracture behavior of TROGAMID CX-7323 (CX-7323) nylon under ballistic impact was performed. Generally, CX-7323 exhibits ductile failure upon impact with a 17-grain fragment simulating projectile(s) (FSP). Penetration is initiated by ductile shearing upon impact. Subsequent tensile stretching allows the penetration event to progress. Material in front of the projectile is pushed out of the way during penetration. Significant elastic recovery of the exit hole is noticed ... |
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| Bulk Nanocomposites Produced by Thermally Activated Severe Plastic Deformation |
Dec-2008 |
9 pages |
| Authors:
J Jr; S Zhang; J Bai; K Shue; X Wu; Y Liu; L Dauerman; Mabesa; M3TECHCENTER LLC CANTON MI
|
| In this paper, several versions of extrusion processes were used to provide severe plastic deformation for grain refinement (with a modified ECAE extrusion) and for grain/fiber alignment (with straight extrusion). The process was performed at elevated temperatures to reduce extrusion pressure, and in order to increase strength and avoid grain growth secondary phases were added or in-situ formed. In addition, this study also attempts to develop a one-step material synthesis ... |
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| Coarsening Kinetics of gamma-prime Precipitates in the Commercial Nickel Base Superalloy Rene88DT (PREPRINT) |
Sep-2008 |
28 pages |
| Authors:
J Tiley; R Banerjee; R Srinivasan; G B Viswanathan; H L Fraser; D M Dimiduk; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| Rene88DT samples were subjected to different cooling rates after a supersolvus treatment, and aged for varying periods of time from 25 to 200 hours at 760 degrees C. Secondary and tertiary gamma-prime precipitate sizes were measured after each heat treatment condition through scanning electron microscopy (SEM) and energy filtered transmission electron microscopy (EFTEM). Coarsening rate constants were calculated and reported from the measured values of precipitate sizes. When describing the ... |
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| Microstructural Effects on the Corrosion Behavior of Alloys and Ceramics |
30-Jun-2008 |
45 pages |
| Authors:
Todd Allen; Lizhen Tan; NATIONAL ASSOCIATION OF CORROSION ENGINEERS HOUSTON TX
|
| The objective of this research was to investigate the effect of microstructure on the corrosion behavior of metals and ceramics. Representative materials from the important engineering alloys and ceramics were studied to determine their corrosion behavior in supercritical water and during cyclic oxidation in air. The materials included Incoloy alloy 800H, Inconel alloy 617, 12%Cr ferritic-martensitic steel HCM12A, and silicon carbide fabricated by means of chemical vapor deposition (CVD). The ... |
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| Electro-Responsive Behaviour Multi-Wall Nanotubes/Gelatin Composites and Cross-Linked Gelatin Electrospun Mats |
11 FEB 2008 |
26 pages |
| Authors:
Soo-Young Park; KYUNGPOOK NATIONAL UNIV DAEGU (SOUTH KOREA) DEPT OF POLYMER SCIENCE
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| Swelling, states of water, morphology, stability in the aqueous solution, and electro-mechano- chemical bending behaviors of the gelatin/chitosan blend system were studied in order to clarify the potential use of this blend system as an actuator. The gelatin/chitosan blend system was prepared in order to avoid dissolution of the pure chitosan film system in an aqueous medium and the rigidity and easy degradation of the pure gelatin system in the ... |
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| Seed Effort Toward "Multiscale Theoretical and Experimental Investigation of the Role of Structural Features on Damage Tolerance and Creep" |
NOV 2007 |
31 pages |
| Authors:
Amit Ghosh; Rick Lee; MICHIGAN UNIV ANN ARBOR DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| This report summarizes research ideas and some results in relation to effort conducted toward understanding the role of grain boundaries and grain boundary defects on the mechanical properties of metals, and with evolving interest in testing and learning the behavior of small specimens. It has been shown that by considering grain boundaries having different properties from grains, strengthening of metals as affected by grain size can be predicted. The analysis ... |
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| Morphological Studies of Bragg Reflection Gratings Written in Holographic Polymer Dispersed Liquid Crystals by Thiol-Ene Photopolymerization (Preprint) |
AUG 2007 |
5 pages |
| Authors:
Timothy J. Bunning; Jeremy M. Wofford; L. V. Natarajan; R. L. Sutherland; Vincent Tondiglia; Pamela Lloyd; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| Recently, a new photopolymerization system for writing visible light initiated thiol-ene based H-PDLC Bragg reflection gratings was developed. Using this new method, Bragg reflection gratings were written with notch wavelengths out into the NIR. The aim of the present work is to determine the grating parameters like spacing, LC width, polymer width and droplet density from morphological studies and compare with those obtained from optical measurements. The electro-optical performance of ... |
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| Growth and Characterization of Carbon Nanotubes on Constantan (Cu-Ni-Mn Alloy) Metallic Substrates Without Adding Additional Catalysts |
Jul-2007 |
6 pages |
| Authors:
J Burke; L Brunke; J Bulmer; J Baca; K Yost; P Barnes; C V Varanasi; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| In this study, metallic constantan (Cu55-Ni44-Mn1 wt %) alloy substrates were investigated as an alternate choice of substrates to grow carbon nanotubes (CNTs). No additional catalysts were used other than the as-rolled and annealed substrates to process CNTs on them. High density CNT growth was observed to take place on these substrates when suitable conditions were used in a thermal chemical vapor deposition (CVD) furnace with C2H2 as the carbon ... |
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| Nanocomposites Derived from Carbon Nanofibers and a Hyperbranched Poly(Ether-Ketone): In Situ Polymerization, Chain-End Modification, and Properties (Preprint) |
MAY 2007 |
41 pages |
| Authors:
David H. Wang; Peter Mirau; Loon-Seng Tan; Bing Li; Christopher Y. Li; Jong-Beom Baek; DAYTON UNIV OH RESEARCH INST
|
| 5-Phenoxyisophthalic acid, an A2B monomer, was easily polymerized via a Friedel-Crafts acylation in poly(phosphoric acid)/phosphorus pentoxide (PPA/P2O5; 1:4 w/w) medium to form a CO2H-terminated hyperbranched poly(ether-ketone), HPB-PEK. Thus, the polymerization of 5-phenoxyisophthalic acid, in the presence of various amounts (1, 2, 5, 10, 20, 30 and 40 wt%) of vapor-grown carbon nanofibers (VGCNF) was performed under similar reaction conditions. The resulting (HPB-PEK)-g-VGCNF nanocomposites were insoluble in dichlorobenzene or toluene, but ... |
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| Enzymatic Decontamination of Environmental Organophosphorus Compounds |
04 DEC 2006 |
13 pages |
| Authors:
Roger M. Leblanc; MIAMI UNIV CORAL GABLES FL
|
| This final report describes the research performed during the award period (June 5, 2003 to December 4, 2006). The main thrust of the research project was to investigate the surface chemistry of and molecular interactions between OP compounds and enzymes. The objective were: i) to characterize the Langmuir films of organophosphorus acid hydrolase (OPH) and organophosphorus acid anhydrase (OPAA) by studying their interfacial and spectroscopic properties at air/water interface; ii) ... |
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| The Effect of Hard Coated Metals on the Thermo-Oxidative Stability of a Branched Perfluoropolyalklyether Lubricant (Preprint) |
OCT 2006 |
39 pages |
| Authors:
Patrick T. Hellman; Jeffrey S. Zabinski; Lois J. Gschwender; Carl E. Snyder; Andras L. Korenyi-Both; DAYTON UNIV OH RESEARCH INST
|
| M-50 and carburized Pyrowear 675(registered) steel coupons deposited with commercially available physical vapor deposited (PVD) TiN, TiCN, TiAlCN, TiCrCN/TiB4C multilayer, electroless Ni (E-Ni) TiN, and E-Ni TiCN coatings were immersed in a branched perfluoropolyalklyether (PFPAE), Krytox AC(registered), in an oxidative environment at temperatures ranging from 315 to 360 deg C for a duration of 24 hours and compared to uncoated coupons. Coated and uncoated Pyrowear 675(registered) coupons demonstrated superior corrosion ... |
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| Corrosion Properties of Ca Based Bulk Metallic Glasses (Preprint) |
OCT 2006 |
24 pages |
| Authors:
James Dahlman; O. N. Senkov; J. M. Scott; D. B. Miracle; SOUTHWESTERN OHIO COUNCIL FOR HIGHER EDUCATION DAYTON
|
| Bulk amorphous metals are attractive materials for several reasons. An absence of microstructural features such as crystal plains, dislocations, grain and phase boundaries contribute to appealing mechanical properties such as high hardness and high specific strength. The amorphous structure also results in attractive magnetic properties such as high magnetic permeability. Corrosion studies have also established amorphous metals as a group of materials with corrosion properties much more desirable than their ... |
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| Transport Imaging in the One Dimensional Limit |
JUN 2006 |
83 pages |
| Authors:
Stephen D. Winchell; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF PHYSICS
|
| Transport imaging is a SEM-based technique used to directly image the motion and recombination of charge in luminescent semiconductors, allowing for the extraction of transport parameters critical to device operation. In this thesis, transport imaging for 1-D structures was initiated with work on sample preparation, modeling and initial characterization. One dimensional structures are being integrated into forefront electronics due to their inherent advantages in size, packing density and power consumption. ... |
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| Improved Electrical Properties of Epoxy Resin with Nanometer-Sized Inorganic Fillers (Preprint) |
MAY 2006 |
5 pages |
| Authors:
John C. Horwath; Daniel L. Schweickart; Guido Garcia; Donald Klosterman; Mary Galaska; Amanda Schrand; Lawrence C. Walko; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| In this study, the average dielectric breakdown voltage of POSS-filled epoxy was increased 34 percent compared to unloaded epoxy. Additionally, scanning electron microscopy showed uniform dispersion of the POSS filler down to a level of 10-100 nm. Dispersion uniformity appears to be a critical parameter in obtaining the desired property enhancements. |
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| Characterization of the Field Emission Properties of Carbon Nanotubes Formed on Silicon Carbide Substrates by Surface Decomposition |
MAR 2006 |
180 pages |
| Authors:
Michael C. Pochet; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Dense arrays of vertically aligned carbon nanotubes (CNTs) form on the surface of silicon carbide wafers during high temperature anneals under moderate vacuum conditions. The novelty of this growth method is that the CNTs form without the aid of a metal catalyst, allowing for potentially impurity-free CNTs to form. In this study, CNT films were grown by the surface decomposition of silicon carbide substrates. The associated field emission characteristics were ... |
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| Study of Quantum Point Contact via Low Temperature Scanning Gate Microscopy |
2006 |
5 pages |
| Authors:
N. Aoki; A. Burke; C. R. da Cunha; R. Akis; D. K. Ferry; Y. Ochiai; ARIZONA STATE UNIV TEMPE DEPT OF ELECTRICAL ENGINEERING
|
| Two types of quantum point contacts have been studied by low temperature scanning gate microscopy. In addition to the usual bright spot, which corresponds to a large conductance change at the constriction, ring structures are observed near the center of the quantum point contact. The ring diameter shrinks with increasing base conductance when the side gate voltage is changed. The rings are thought to relate to the observation of impurity ... |
|
| STM Studies of Semiconductor Qubit Candidates |
30 NOV 2005 |
13 pages |
| Authors:
J. C. Davis; CORNELL UNIV ITHACA NY OFFICE OF SPONSORED PROGRAMS
|
| We developed novel spectroscopic STM instruments for study of individual atom qubits. |
|
| Hydrogen Termination Following Cu Deposition on Si(001) |
08 APR 2005 |
5 pages |
| Authors:
L. A. Baker; A. R. Laracuente; L. J. Whitman; NAVAL RESEARCH LAB WASHINGTON DC
|
| We describe the surface structures following submonolayer Cu deposition on Si(001) and subsequent hydrogen termination as characterized by scanning tunneling microscopy. Cu adsorption at 870 K results in a characteristic (2*8) island+vacancy structure, as previously reported. In addition, occasional structures are observed attributed to Cu in surface interstitial sites. After H termination, the dominant features of the island+vacancy structure remain, but the size and distribution of the structures are significantly ... |
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| ZnS-Based Photonic Crystal Phosphors Fabricated Using Atomic Layer Deposition |
2004 |
5 pages |
| Authors:
J. S. King; C. W. Neff; S. Blomquist; E. Forsythe; D. Morton; C. J. Summers; GEORGIA INST OF TECH ATLANTA SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
|
| The infiltration by atomic layer deposition of three-dimensional opal structures has been investigated as a means of fabricating photonic crystal phosphors. ZnS:Mn infiltrated and inverse opals have been demonstrated with filling fractions >95%. Characterization of these structures by scanning electron microscopy, specular reflectance, and photoluminescence is reported. Specular reflectance measurements confirm successful infiltration, and demonstrate modification of the electromagnetic density of states consistent with calculated photonic (111) pseudo band gaps. ... |
|
| Changes in Trace and Minor Constituents and Associated Micro-architecture of Montastrea faveolata during Time of Stress |
Sep-2003 |
5 pages |
| Authors:
Charles W Holmes; Noreen A Buster; James E Sorauf; J H Hudson; Cynthia Kester; GEOLOGICAL SURVEY SAINT PETERSBURG FL
|
| As corals grow, they secrete a calcareous skeleton with the aid of photosynthetic activity of endosymbiotic dinoflagellates. The rate of this secretion varies annually which produces annual bands. Entrapped with the carbonate are trace substances that record the chemistry of the surrounding ocean. Detailing these changes in chemistry requires careful high-resolution sampling. New procedures involving laser ablation inductive couple plasma mass spectroscopy (LA-ICP/MS) provides a unique method that does not ... |
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| Stoichiometry-Induced Roughness on Antimonide Growth Surfaces |
23 APR 2001 |
4 pages |
| Authors:
A. S. Bracker; B. Z. Nosho; W. Barvosa-Carter; L. J. Whitman; B. R. Bennett; B. V. Shanabrook; J. C. Culbertson; NAVAL RESEARCH LAB WASHINGTON DC
|
| Phase shifts in the intensity oscillation of reflection high-energy electron diffraction spots provide evidence for monolayer island formation on AlSb that is caused by sudden changes in surface stoichiometry. High-resolution scanning tunneling microscopy confirms the interpretation of the phase shift. These results are consistent with a previous structural assignment of the AlSb beta(4 x 3) and alpha(4 x 3) surface reconstructions and provide guidelines for producing smooth interfaces in antimonide-based ... |
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| A Monohydride High-Index Silicon Surface: Si(114):H-(2x1) |
08 MAR 1999 |
4 pages |
| Authors:
A. Laracuente; S. C. Erwin; L. J. Whitman; NAVAL RESEARCH LAB WASHINGTON DC
|
| We describe the adsorption of H on Si(114)-(2x1) as characterized by scanning tunneling microscopy and first-principles calculations. Like Si(001)-and despite the relative complexity of the (114) structure-a well-ordered, low-defect-density monohydride surface forms at approx. 400 deg. C. Surprisingly, the clean surface reconstruction is essentially maintained on the (2 x 1) monohydride surface, composed of dimers, rebonded double-layer steps, and nonrebonded double-layer steps, with each surface atom terminated by a single ... |
|
| The Structure of Si(112):Ga-(N x 1) Reconstructions |
01-Jan-1999 |
7 pages |
| Authors:
L J Whitman; A A Baski; S C Erwin; VIRGINIA COMMONWEALTH UNIV RICHMOND DEPT OF PHYSICS
|
| We have studied the structure of Si(112):Ga-(N*1) reconstructions using atomic-resolution scanning tunneling microscopy and first-principles calculations. The nanofaceted clean Si(112) surface becomes planar following the adsorption of Ga, which forms long chains on the surface interrupted by isolated quasi-periodic defects. The defects create a mixture of (N*1) structures (N~4-7) with 5 1 and 6 1 unit cells most common. We demonstrate that this structure consists of a chain of Ga ... |
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| Structure of InAs/AlSb/InAs Resonant Tunneling Diode Interfaces |
AUG 1998 |
7 pages |
| Authors:
B. Z. Noshoa; W. H. Weinberg; J. J. Zinck; V. Shanabrook; B. R. Bennett; L. J. Whitman; CALIFORNIA UNIV SANTA BARBARA CENTER FOR QUANTIZED ELECTRONIC STRUCTURES
|
| We have used in situ plan-view scanning tunneling microscopy to study the surfaces and interfaces within an InAs/AlSb/InAs resonant tunneling diodelike structure grown by molecular beam epitaxy. The nanometer and atomic-scale morphologies of the surfaces have been characterized following a number of different growth procedures. When InAs(001)-(234) is exposed to Sb2 a bilayer surface is produced, with 1 monolayer (ML) deep (3 ) vacancy islands covering approximately 25% of the ... |
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| Epitaxial Growth, Structure, and Composition of Fe Films on GaAs(001)-2x4 |
01 APR 1996 |
7 pages |
| Authors:
E. Kneedler; P. M. Thibado; B. T. Jonker; B. R. Bennett; B. V. Shanabrook; R. J. Wagner; L. J. Whitman; NAVAL RESEARCH LAB WASHINGTON DC
|
| The structure and composition of Fe films grown on As-terminated GaAs(001)-234 surfaces at 175 C has been studied in situ with scanning tunneling microscopy (STM), photoelectron diffraction (PED), and x-ray photoelectron spectroscopy (XPS). The GaAs surfaces were prepared by molecular beam epitaxy (MBE) and exhibited large atomically well-ordered terraces. We find that the 234 reconstruction has a significant impact on the Fe nucleation and growth, with initial nucleation occurring at ... |
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| Compositional and Thermal Effects on Chemically Processed AlN-BN Nanocomposite Powders. |
1994 |
|
| Authors:
G. M. Chow; T. D. Xiao; X. Chen; K. E. Gonsalves; NAVAL RESEARCH LAB WASHINGTON DC
|
 | Powders of nanocrystalline aluminum nitride (AlN) and boron nitride (BN) were prepared via a chemical route. Precomposite gels, which were obtained from ammonolysis of aqueous solutions of boric acid, urea, and aluminum chloride hexahydrate, were thermally processed to produce AlN-BN nanocomposite powders with a wide range of compositions. These powders were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The structure, morphology, and ... |
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| Laser Surface Coating of a Bioceramic Composite Layer. |
1993 |
|
| Authors:
Yaping Zhang; Jiacheng Gao; Jifu Tan; Zhirong Zhou; CHONGQING UNIV (CHINA)
|
| In this paper laser surface coating of a step bioceramic composite layer which was preformed by paving step bioceramic or CaH(PO4)2 H2O-CaCO3 powders on austenic stainless steel was studied. The results of scanning electron microscopy, electron diffraction spectroscopy and X-ray diffraction analyses show that the main factors that are advantageous to the formation of the bioceramic coating are the lower power and higher scan speed of the laser, when the ... |
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| Reactive Magnetron Sputtering of Zirconium Carbide Films Using Ar-CH4 Gas Mixtures. |
1993 |
|
| Authors:
J. Brueckner; T. Mantyla; TECHNISCHE UNIV CHEMNITZ (GERMANY)
|
| Zirconium carbide coatings have been produced by reactive r.f. sputtering on cold-rolled steel samples. The films were deposited in an argon-methane atmosphere. The influence of total pressure, methane partial pressure, substrate temperature and bias voltage on the structure and properties was investigated. The coatings were mainly characterized by X-ray diffraction (XRD), scanning electron microscopy and hardness measurements. Energy dispersive X-ray spectroscopy analysis was used to detect impurities such as argon. ... |
|
| Heteroepitaxial Diamond Growth |
01 NOV 92 |
97 pages |
| Authors:
R. J. Markunas; R. A. Rudder; J. B. Posthill; R. E. Thomas; G. Hudson; RESEARCH TRIANGLE INST RESEARCH TRIANGLE PARK NC
|
| Work at Research Triangle Institute during this quarter concentrated on establishing directions and meaningful collaborations through which progress towards large-area, single-crystal diamond could be obtained. Three formal subcontracts with Jerry Whitten (NCSU), Max Swanson (UNC), and Robert Nemanich (NCSU) on the RTI prime have been established to pursue ab initio diamond surface kinetics, ion implantation studies, and atomic scale characterization of diamond respectively. The program here at RTI has adopted ... |
|
| A Comparison Study of Diamond Films Grown on Tungsten Carbide Cobalt Tools Inserts With CH(4) and CF(4) Gas Sources |
NOV 92 |
32 pages |
| Authors:
K. J. Grannen; F. Xiong; R. P. Chang; NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The results of a comparison study of continuous diamond coatings deposited on tungsten carbide-6% cobalt tool inserts using CF4, and CH4, gas sources are presented. The CH4, grown diamond film utilizes a thin (1200 A) amorphous silicon interlayer for adhesion while the CF4, diamond film is deposited directly onto the tool insert. Diamond films produced with CF4, gas have much higher growth rates and better adhesion than diamond films grown ... |
|
| Adhesion and Corrosion Behavior of Al-Zn and TiN/Ti/TiN Coatings on a DU-0.75 WT% Ti Alloy, |
Aug-1992 |
18 pages |
| Authors:
F C Chang; M Levy; R Huie; M Kane; P Buckley; Z Kattamis; G R Lakshminarayan; ARMY LAB COMMAND WATERTOWN MA MATERIAL TECHNOLOGY LAB
|
| Al-Zn alloy and multilayer TiN/Ti/TiN thin coatings were deposited on DU-0-75Ti alloy specimens by a cathodic arc plasma physical vapor deposition process. The quality, soundness and adhesion of the coatings to the substrate were evaluated by automatic scratch testing, in combination with optical and scanning electron microscopy examination of the scratch morphology. The galvanic corrosion behavior of DU-0.75Ti alloy coupled to the coated alloys and aluminum alloy 7075-T6 was also ... |
|
| Structural and Tribiological Studies of MoS2 Solid Lubricant Films Having Tailored Metal-Multilayer Nanostructures |
15 DEC 91 |
36 pages |
| Authors:
M. R. Hilton; R. Bauer; S. V. Didziulis; M. T. Dugger; J. M. Keem; AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS
|
| Molybdenum disulfide (MoS2) solid lubricant films were prepared by rf magnetron sputtering on 440C steel, 52100 steel, and Si substrates. This study concentrated on films that were multilayer coatings of MoS2 with either Ni or Au-Pd(20%) metal interlayers. Multilayer thickness ranged from 0.2 run to 1.0 run while the multilayer periodic spacing ranged from 3 to 10 run. Scanning electron microscopy and X-ray diffraction revealed that the multilayer films had ... |
|
| Strength and Microstructure of Ceramics |
OCT 91 |
|
| Authors:
Brian R. Lawn; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD CERAMICS DIV
|
| Results of a program on the toughness properties of monophase and two phase ceramics that toughen by bridging are presented. Fracture mechanics models describing this behavior, in the particular context of strength, are developed. Results of strengths tests confirming the essential predictions of the theory are presented. Innovative processing routes suggested by the models are shown to lead to two phase composites with impressive flaw insensitivity. A partial list of ... |
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| Investigation of Fatigue and Crack Propagation Behavior of Adhesives. |
OCT 1972 |
|
| Authors:
William B. Jones Jr.; david h. kaelble; Wolfang G. Knauss; ROCKWELL INTERNATIONAL CORP MCGREGOR TEX ROCKETDYNE DIV
|
| Fracture parameters were identified and approximate analytical descriptions of their influence on strength of the adhesive joints was developed. After an initial screening of potential materials, physical and mechanical properties of one brittle and one ductile adhesive were measured in Phase I. Properties were then used in stress analyses and fracture reations were deve-loped in Phase II. Special features of the analyses were de-tailed and particular parameters of adhesive joints ... |
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Reports by Keyword(s)
SCANNING ELECTRON MICROSCOPY
