bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural and Magnetic Properties of Ion Beam Deposited Nanocrystalline Al-Co and Al-Co-O Films
Authors: Khan H. R. , Brouers F. 
Published: September 2012

AbstractNanocrystalline films of Al-Co and Al-Co-O are deposited on glass substrates using Ar and (Ar + O2) gas mixture by IB and IAB deposition techniques. The structure of the films is investigated by X-ray diffraction. Annealed (500°C/ 0.5 h / Vacuum) films show a preferred Co<111> + Al<200> crystallographic orientation. The crystallite size estimated from the line broadening of Co<111> + Al<2007gt;reflections lies between 4 and 12 nm. The value of Mx/Ms increases with decreasing Co concentration from 0.2 (74 at.%) to 0.4 (46 at.%) for IB(Ar) films, where Mr and Ms are the remanence and saturation magnetizations respectively. IB (Ar + O2) and IAB (Ar + O2) films of the same composition A154Co46Ox show different magnetic behaviour.
Alpha Particle Beam Interactions with Fe-Based and FeCo-Based Amorphous Magnets
Authors: Sorescu Monica , Barb D. 
Published: September 2012

AbstractSamples of Fe78B13Si1 and Fe66Co18B15Si1 metallic glasses were irradiated with alpha particle beams (W=2.8 MeV) using radiation doses of 1016 and 1017 cm2. Irradiation-induced effects on the magnetic and structural properties of alloy samples were studied by transmission and conversion electron Mbssbauer spectroscopy. The evolution of phases and microstructure during the radiation-induced amorphous-to-crystalline transformation was found to depend on the particle flux and sample composition. Differences between bulk and surface irradiation behaviors were demonstrated.
Study of the Ion-Acoustic Effect using Focused Ion Beams
Authors: Teichert J. , Bischoff L. , Köhler B. 
Published: September 2012

AbstractAcoustic waves induced by an intensity-modulated focused ion beam (FIB) have been measured. The experiments were performed with Ga+ ions of 35 keV at a current of 3 nA and variable chopping frequency up to 10 MHz. The acoustic signals were detected by means of a piezoelectric sensor with integrated pre-amplifier. In the paper the experimental setup and the results of first measurements are presented. Evidence for FIB induced acoustic waves has been found.
Growth and Mechanical and Tribological Characterization of Multi-Layer Hard Carbon Films
Authors: Ager J. , Brown I. , Monteiro O. , Knapp J. A. , Follstaedt D. M. , Nastasi M. , Walter K. C. , Maggiore C. J. 
Published: September 2012

AbstractVacuum-arc deposition is used to deposit multilayer carbon films by modulating the sample bias during deposition. The effect of varying the sublayer thickness in multilayer films consisting of alternating layers of “hard” (68.4 GPa, -100 V bias) and “soft” (27.5 GPa, -2000 V bias) was investigated. Films consisting of equal thickness layers of hard and soft material and an individual layer thickness varying from 10 to 35 nm were deposited. Mechanical property measurements were obtained by finite element modeling of nanoindentation load-displacement curves. The film hardness values were about 20% below the average of the component layers and relatively independent of the layer thickness. TEM investigation revealed deterioration of the multilayer structure when the sublayer thickness was below 15 nm due to implantation damage of the hard layers caused by the energetic C+ ions of the soft layers (-2000 V bias) deposited over them. Pin-on-disk wear tests show that the wear rate drops when sublayer thickness is decreased below 20 nm and remains constant with further decreases in the layer thickness.
Thermal Annealing Behavior of Si-DLC Ibad Coatings
Authors: Fountzoulas C. G. , Demaree J. D. , Sengupta L. C. , Hirvonen J. K. 
Published: September 2012

AbstractAmorphous, 700 nm thick, diamond-like carbon coatings containing silicon (Si-DLC), farmed by Ar+ ion beam assisted deposition (IBAD) on silicon substrates, were annealed in air at temperatures ranging from room temperature to 600°C for 30 minutes. RBS analysis showed that the composition of the films remained the same up to 200°C, but at higher temperatures the Si-DLC coatings began to oxidize at the outer surface of the coating, forming a surface layer of SiO2. After in-air annealing at 600°C the coating had been completely converted to SiO2, with no trace of carbon seen by RBS. FTIR spectra of the unannealed coatings showed a very broad mode typical of Si-DLC bonding as well as some absorption features associated with Si and SiO2. Above 200°C the transmission mode shifted to higher frequencies which may be caused by the growth of SiO2 and the decrease of the Si-DLC film thickness. The room temperature ball-on-disk friction coefficient of the coating against a 1/2′′ diameter 440 C steel ball at 1 N load ranged from 0.2 for the original coating up to 0.5 after a 100° anneal and returned to 0.2 after annealing at 200–400°C and fell to 0.12 after a 500°C exposure. The average Knoop microhardness (uncorrected for substrate effects) was 10 GPa (1,000 KHN) for coatings annealed at temperatures as high as 400°C. All coatings up to 500 °C passed the qualitative “Scotch Tape” test.
Deposition and Properties of Doped Diamondlike Carbon Films Produced by Dual-Source Vacuum Arc Plasma Immersion
Authors: Monteiro O. R. , Delplancke-Ogletree M. P. , Brown I. G. , Ager J. W. 
Published: September 2012

AbstractDiamond-like carbon films with mechanical properties approaching those of diamond have been consistently produced by cathodic vacuum arc based techniques. These films have been successfully used in applications where enhanced hardness and wear resistance are required Such DLC films have two major drawbacks that prevent their application in other areas: a high level of internal stresses, which promotes failure by spallation of thick films; and the loss of mechanical properties at temperatures higher than 300°C. In this paper we describe the effect of doping elements on the room-temperature mechanical properties and on the thermal stability of DLC films upon annealing in air. The effect of the presence of W and Ti was investigated and compared to pure DLC. The films were produced by dual-source metal plasma immersion ion implantation and deposition with magnetic filtering to remove macroparticles from the plasma; dopant content was controlled by varying the relative pulse duration of the two plasma sources. Microstructural and chemical characterization of the films are presented.
Carbon Nitride Film Formation by Low Energy Positive and Negative Ion Beam Deposition
Authors: Tsubouchi N. , Horino Y. , Enders B. , Chayahara A. , Kinomura A. , Fujii K. 
Published: September 2012

AbstractUsing a newly developed ion beam apparatus, PANDA (Positive And Negative ions Deposition Apparatus), carbon nitride films were prepared by simultaneous deposition of mass-analyzed low energy positive and negative ions such as C2-, N+, under ultra high vacuum conditions, in the order of 10−6 Pa on silicon wafer. The ion energy was varied from 50 to 400 eV. The film properties as a function of their beam energy were evaluated by Rutherford Backscattering Spectrometry (RBS), Fourier Transform Infrared spectroscopy (FTIR) and Raman scattering. From the results, it is suggested that the C-N triple bond contents in films depends on nitrogen ion energy.
Large Area Surface Treatment by Ion Beam Technology
Authors: Wu R. L. C. , Lanter W. 
Published: September 2012

AbstractAn ultra high vacuum ion beam system, consisting of a 20 cm diameter Rf excilted (13.56 MHz) ion gun and a four-axis substrate scanner, has been used to modify large surfaces (up to 1000 cm2) of various materials, including; infrared windows, silicon nitride, polycrystalline diamond, 304 and 316 stainless steels, 440C and M50 steels, aluminum alloys, and polycarbonates; by depositing different chemical compositions of diamond-like carbon films. The influences of ion energy, Rf power, gas composition (H2/CH4 , Ar/CH4 and O2/CH4/H2), on the diamond-like carbon characteristics has been studied. Particular attention was focused on adhesion, environmental effects, IR(3–12 μm) transmission, coefficient of friction, and wear factors under spacelike environments of diamond-like carbon films on various substrates. A quadrupole mass spectrometer was utilized to monitor the ion beam composition for quality control and process optimization.
Evaluating Mechanical Properties of Thin Layers using Nanoindentation and Finite-Element Modeling: Implanted Metals and Deposited Layers
Authors: Knapp J. A. , Follstaedt D. M. , Barbour J. C. , Myers S. M. , Ager J. W. , Monteiro O. R. , Brown I. G. 
Published: September 2012

AbstractWe present a methodology based on finite-element modeling of nanoindentation data to extract reliable and accurate mechanical properties from thin, hard films and surface-modified layers on softer substrates. The method deduces the yield stress, Young's modulus, and hardness from indentations as deep as 50% of the layer thickness.
Properties of Ion Implanted Ti-6Al-4V Processed using Beamline and PSII Techniques
Authors: Walter K. C. , Williams J. M. , Woodring J. S. , Nastasi M. , Poker D. B. , Munson C. M. 
Published: September 2012

AbstractThe surface of Ti-6Al-4V (Ti64) alloy has been modified using beamline implantation of boron. In separate experiments, Ti64 has been implanted with nitrogen using a plasma source ion implantation (PSII) technique utilizing either ammonia (NH 3), nitrogen (N2), or their combinations as the source of nitrogen ions. Beamline experiments have shown the hardness of the N-implanted surface saturates at a dose level of ˜4× 1017 at/cm2 at ˜10 GPa. The present work makes comparisons of hardness and tribological tests of (1) B implantation using beamline techniques, and (2) N implanted samples using ammonia and/or nitrogen gas in a PSII process. The results show that PSII using N2 or NH3 gives similar hardness as N implantation using a beamline process. The presence of H in the Ti alloy surface does not affect the hardness of the implanted surface. Boron implantation increased the surface hardness by as much as 2.5x at the highest dose level. Wear testing by a pin-on-disk method indicated that nitrogen implantation reduced the wear rate by as much as 120x, and boron implantation reduced the wear rate by 6.5x. Increased wear resistance was accompanied by a decreased coefficient of friction.
Thermomechanically Modulated Nanoscale Multilayered Materials for Application in Electromagnetic Gun Systems
Authors: Otooni M. A. , Brown I. G. , Monteiro O. 
Published: September 2012

AbstractFired rails from electromagnetic railguns show severe damage from arcing and tribological mismatch. We have fabricated and studied several different nanoscale multilayered materials as possible routes to improve the thermal transport and thermomechanical properties of the rail and armature materials. A vacuum-arc-based plasma deposition technique with wide control of ion energy was used for the film synthesis, and high-energy high-dose (energy up to ˜ 150 keV, dose up to ˜ 1 × 1017cm−2) metal ion implantation was also used. The multilayered film structures formed and investigated included sublayers of Ti, TiCo, ZrN, TaN and dlc (diamond-like carbon) in the following combinations: (i) ZrN on TiCo on TaN on dlc on a Cu substrate, (ii) ZrN on TiCo on TaN on dlc on an Al substrate, (iii) TiN on TiCo on TaN on a stainless steel substrate, and (iv) Ti on TiCo on a stainless steel substrate. Individual sublayer film thickness was in the range of 400Å-7μ. The surfaces were characterized by SEM, TEM, RBS, high energy electron diffraction, arid microhardness measurements. Significant improvements in the material surface properties were obtained for virtually all of the surface structures investigated. Here we outline the material synthesis and surface modification techniques used and the materials characterization results obtained.
Preparation of TiC and TiC/DLC Multilayers by Metal Plasma Immersion Ion Implantation and Deposition: Relationship between Composition, Microstructure and Wear Properties
Authors: Delplancke-Ogletree M. P. , Monteiro O. R. , Brown I. G. 
Published: September 2012

AbstractWe have used pulsed vacuum arc deposition to prepare TixCy films and multilayer structures of TixCy / diamondlike carbon (DLC) in a dual plasma source set-up. The composition of the monolithic films was controlled by varying the pulse duration of each plasma gun. During the deposition, a repetitively pulsed bias voltage was applied to the substrate in order to improve the adhesion to the substrate and between the individual layers. For the multilayers, the carbon and Ti guns were synchronously pulsed during deposition of the TixCy, and the Ti gun was not operated during the DLC deposition. Multilayers with different periodicities were synthesized. The deposited films were analyzed by various techniques including XPS, AES, TEM, EELS, and XRD to characterize the composition, bonding states, and microstructure. Special attention was given to the interface thickness in relation to the applied bias voltage. Tribological properties such as friction coefficient and wear resistance were measured, and correlated to the composition and microstructure of the films.
Al / Al-N / Ain Compositional Gradient Film Synthesized by Ion-Beam Assisted Deposition Method
Authors: Amamoto Yoshiki , Uchiyama Shingo , Watanabe Yoshihisa , Nakamura Yoshikazu 
Published: September 2012

AbstractAl / AI-N / AIN compositional gradient thin film was deposited on a Si(100) substrate at room temperature by ion-beam assisted deposition method, with a diminishing ion beam current from 1.4 to 0 mA at increments of 0.3 mA in order to gradually decrease the nitrogen to aluminum ratio at the substrate. The gradual Al and AIN variation in composition was shown by the change of the Al / N atomic ratio analysed by the energy dispersive X-ray spectroscopy(EDX) and the X-ray photoelectron spectroscopy (XPS) in the cross section of the film. The formation of crystalline Al metal and AIN ceramic layer on the Si substrate was revealed by X-ray diffraction(XRD). The cross sectional image taken by high resolution transmission electron microscope (HRTEM) showed a nano-sized crystalline AI-N ceramic material and the flat interface between the Si substrate and the AIN film.
The Effect of Impurity Content and Ion Mass on the Depth Profiles of Vacancy-Type Defects in MeV Implanted Si
Authors: Libertino S. , Coffa S. , Privitera V. , Priolo F. 
Published: September 2012

AbstractWe used deep level transient spectroscopy to determine the concentration and depth profile of the defects introduced by MeV He and Si implants in n-type crystalline Si. We have found that only ∼ 16% of the Frenkel pairs generated by the ion escapes recombination and is stored into room temperature stable defects such as divacancies and oxygen vacancy complexes. For a light ion (He), the depth distribution of these defect complexes is strongly dependent on the O content of the substrate: it mirrors the initial distribution of I-V pairs, as calculated by TRIM (a Monte Carlo Code) when the O content is high (∼ 1018/cm3) while it can be much wider (up to 2 μm) in a highly pure (low O content) epitaxial substrate. This effect is due to a long range migration of vacancies before clustering or trapping at impurities. This migration is strongly inhibited for an ion of higher mass (such as Si) since in a denser collision cascade direct clustering is strongly favoured with respect to agglomeration of migrating defects.
A Study of the Tribological Characteristics of Titanium Nitride Film Prepared by the Dynamic Ion Beam Mixing Method for Application on Sliding Bearings
Authors: Nagasaka H. , Koizumi T. 
Published: September 2012

AbstractTitanium nitride (TiN) film for the bearings and seals used in rotating machinery has been developed by the dynamic-ion-beam-mixing (DM) process, which combines Ti vapor deposition with simultaneous nitrogen ion beam irradiation. In this study, the tribological properties of the DM-TiN film on martensitic stainless steel (SS) were investigated for application on the bearings of submerged pumps. The critical contact pressure for seizure, wear resistance and friction coefficient properties of DM-TiN film paired with cast iron were investigated under practical sliding conditions, and compared with the hard surface materials of nitriding AISI 420 SS and nitriding 41CrAlMo74 (CrAlMo) steel. The results show that DM-TiN film is superior to these nitriding steels in surface contact pressure for seizure and wear resistance.
Preparation and Characterization of Tin Oxide Films by Ion-Assisted Deposition
Authors: Choi W. K. , Cho J. S. , Song S. K. , Kim Y. T. , Yoon K. H. , Jung H.-J. , Koh S. K. 
Published: September 2012

AbstractUndoped tin oxide films were grown on Si substrates by a reactive ion-assisted deposition technique in which oxygen ions were irradiated on depositing Sn particles. In order to investigate the oxidation from SnO to SnO2, the effects of initial oxygen contents and heat treatment on the final crystalline structure of tin oxide films were thoroughly examined. Oxygen to Sn metal ratio (No/Nsn) of as-deposited films were controlled from 1.1 to 1.9 by varying the relative arrival ratio (F) of oxygen ion to Sn particle from 0.025 to 0.1. Heat treatment was carried out in two different ways; one was post vacuum-annealing at 400 ∼ 600°C and the other was in-situ annealing 400 ∼ 500°C. Crystalline structure of as-deposited tin oxide films at room temperature was amorphous. After post-annealing at 400°C, only SnO phase was found below No/Nsn= 1.6 in x-ray diffraction and crystalline structure of the films comprising higher oxygen contents still appeared to be amorphous. Even though the films still showed SnO phase until Γ50 after 500°C post-annealing, however, mixed structures of SnO, SnO2, and intermediate Sn2O3/Sn3O4 were observed for the films Γ75 and Γ100 with higher oxygen contents. At 600°C annealing, perfect SnO2 phase was attained for the films having No/Nsn=1.9. On the other hand, pure polycrystalline SnO2 films could be obtained by in-situ annealing at low temperature. The values of No/Nsn and the chemical shifts with the variation of oxidation were carefully determined by the comparison of Sn MNN and O KLL Auger transitions. Surface microstructure of deposited films was also analyzed using a scanning electron microscopy (SEM) and an atomic force microscope (AFM).
Engineered Nanocrystallites for Enhanced Performance of Ceramic Coatings by Ion Beam Assisted Deposition
Authors: Namavar F. , Haupt J. , Tobin E. , Karimy H. , Trogolo J. , Colter P. , Yoganathan M. , Jollimore C. , Bricault R. , Hirvonen J. P. , Ayer R. 
Published: September 2012

AbstractTypical high-temperature thin-film deposition techniques are not suitable for certain substrates such as polymers and thermally-sensitive steels. In this work, ion beam assisted deposition (IBAD) was used to deposit ceramic and metallic films at temperatures below 150°C with nanocrystalline (< 100Å diameter) grain size. Nanoindentation studies of these films have shown hardnesses 50 to 100% greater than larger-grained films and, in some cases, fracture toughness approaching that of Si3N4.By combining chromium evaporation with nitrogen beam bombardment, hard, adherent CrN films without any porosity have been produced at low temperatures with a N/Cr arrival ratio of about 1. The grain size is typically smaller than 100Å and hardness is typically higher than 25 GPa. For a N/Cr arrival ratio slightly less than 1, we observed possible grain boundary porosity. However, even with porosity, hardness is typically 20 to 24 GPa for grain sizes smaller than 100Å. For a N/Cr arrival ratio of 1/4 we deposited elemental Cr with a grain size of 300 to 500Å and a hardness greater than that of silicon (12 GPa). Using Ar ions and a N backfill, we produced elemental Cr containing a mixture of coarse (120 to 150Å) and fine (25 to 30Å) grains. For high-temperature deposition of CrN, the grain size increases (200 to 600Å) with a noticeable decrease in hardness. Mechanical properties of CrN are greatly influenced by impurities, as well as by surface conditioning of the substrate.TiN films having gold color and grain sizes from 50 to 1000Å have been produced at low temperatures. Nanoindentation measurements of hardness and fracture toughness indicate that impurity-free TiN (with grains smaller than 100Å) has a hardness higher than 25 GPa and a fracture toughness close to that of Si3N4, but with higher wear resistance. Mechanical properties of our TiN films are greatly influenced by impurities, particularly oxygen, although it does not influence the gold color of TiN.
Defect Diffusion During Annealing of Low-Energy Ion-Implanted Silicon
Authors: Bedrossian P. J. , Caturla M.-J. , Rubia T. Diaz De La 
Published: September 2012

AbstractWe present a new approach for investigating the kinetics of defect migration during annealing of low-;energy, ion-implanted silicon, employing a combination of computer simulations and atomic-resolution tunneling microscopy. Using atomically-clean Si(111)-7×7 as a sink for bulk point defects created by 5 keV Xe and Ar irradiation, we observe distinct, temperature-;dependent surface arrival rates for vacancies and interstitials. A combination of simulation tools provides a detailed description of the processes that underly the observed temperature-dependence of defect segregation, and the predictions of the simulations agree closely with the experimental observations.
Effects of Interstitial Clustering on Transient Enhanced Diffusion of Boron in Silicon
Authors: Solmi S. , Valmorri S. 
Published: September 2012

AbstractA simulation model for Boron diffusion which takes into account the aggregation of the excess interstitials in clusters, and subsequently, the dissolution of these defects, is proposed. The interstitial supersaturation and generation rate are determined according to the classical theory of nucleation and growth of particles, in analogy with the precipitation of a new phase in heavily doped silicon. The clusters are considered as precipitates formed by interstitial Si atoms. The B diffusion is modelled on the basis of the dopant-interstitial pair diffusion mechanism. The clusters dissolution during annealing maintains nearly constant, for a long period, the interstitial supersaturation and the related enhancement of the boron diffusion. This gives a good account of the diffusion results over a large range of experimental conditions. Furthermore, this approach describes most of the behavior of the transient enhanced diffusion (TED), like the temperature dependence of the level of the B diffusion enhancement, the dependence of the duration of the phenomenon on implanted dose, and the scarce dependence on the damage distribution in depth. The results of the simulations are compared with experimental data on the kinetics of interstitial cluster dissolution and of B TED.
Formation of ZnSe/GaAs Heterovalent Heterostructures by Movpe
Authors: Funato Mitsuru , Aoki Satoshi , Fujita Shizυo , Fujita Shigeo 
Published: September 2012

AbstractZnSe/GaAs (001) heterovalent heteгostructures are fabricated by metalorganic vapor phase epitaxy. During the growth, both GaAs and ZnSe surfaces are kept atomically flat to achieve precise control of the interface formation. Interface composition, Ga/As, are controlled by means of either Zn or Se treatment of a GaAs surface, and then ZnSe growth follows. Consequently, it is revealed by X-ray photoemission spectroscopy (XPS) that artificial control of Ga/As from 1.0 to 2.8 leads to the variation of valence band offsets from 0.6 to 1.1 eV. Based on the electron counting model and layer-attenuation model, it is proposed that the As plane just below the interface consists of As, anti-site Ga and As vacancy.