bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stoichiometric Disturbance in InP Measured During Ion Implantation Process
Authors: Haberland D. , Harde P. , Nelkowski H. , Schlaak W. 
Published: March 2011

ABSTRACTTo measure the sputtered ions during implantation a specially designed UHV-target chamber with a SIMS apparatus was set up. Quantitative analysis are possible with an Auger spectrometer. Disturbances in the stoichiometry in InP are measured during implantation of Sn. The enrichment of the doped surface of InP with the lighter component phoshorus will be discussed in consideration of preferential sputtering and recoil effects during implantation. Measured depth profiles of Sn in InP will be compared with calculated distributions on condition that sputtering takes place. The sputtering yield of InP bombarded by 120 keV Sn+ is 17±5.
Anisotropic Transport of Impurities in Ion Mixing
Authors: Matteson S. , Keenan J.A. , Pinizzotto R.F. 
Published: March 2011

ABSTRACTExperimental investigations of the redistribution of a thin (1nm) Sn marker layer lying between two thicker dissimilar layers (Ge and Si) during 360 keV As ion irradiation are reported. Several permutations of layer arrangements were tested, i.e. Si/Sn/Ge, Ge/Sn/Si, Si/Sn/Si and Ge/Sn/Ge. It was also found that in the dissimilar “diffusion” couples, the Sn drifts in the Ge rich direction, regardless of whether the Ge is on the surface side or the substrate side of the marker. This phenomemon of anisotropic transport is interpreted as a drift induced by a gradient in the “diffusion” coefficient. The radiation resistance of concentrated alloys is discussed in the light of this phenomenon.
Magnetic Properties of Iron Implanted Polymers and Graphite
Authors: Koon N. C. , Weber D. , Pehrsson P. , Schindler A. I. 
Published: March 2011

ABSTRACTWe have measured the magnetic properties of highly oriented pyrolytic graphite (HOPG), polyethylene (PE), and polyvinylidine fluoride (PVF2), implanted with fluences of 25 keV iron atoms ranging from 1016 to 1017 atoms/cm2 . The lowest fluence specimens were paramagnetic down to 2 K, with evidence for clusters of only a few spins, while the highest fluence specimens were clearly ferromagnetic, with magnetization curves resembling those of a set of randomly oriented soft magnetic planes. The critical fluence for formation of a ferromagnetic state appears to be between 1 and 3 × 1016 atoms/cm2 at 25 keV. Theseresults can be qualitatively understood based on the critical density for percolation of near neighbor exchange interactions.
Magnetoreflection in Ion-Implanted Graphite
Authors: Mcneil L.E , Elman B.S. , Dresselhaus M.S , Dresselhaus G. , Venkatesan T. 
Published: March 2011

ABSTRACTThe use of a hot stage (T ∼ 600°C) for ion implantation into graphite permits the introduction of foreign species into the host material while eliminating most of the lattice damage associated with ion implantation at room temperature. This permits the use of the magnetoreflection technique for examination of changes in the electronic band structure induced by implantation Samples of graphite implanted with 31P and 11B at various energies and fluences are examined, and the in-plane and c-axis disorder are characterized using Raman spectroscopy and Rutherford Backscattering Spectrometer (RBS) techniques. Implantation-induced changes in the electronic band structure are interpreted in terms of the Slonczewski-Weiss- McClure band model. Small changes are found relative to the band parameters that describe pristine graphite.
Modifying Polycrystalline Films Through Ion Channelling
Authors: Iverson R. B. , Reif R. 
Published: March 2011

ABSTRACTA novel low-temperature process to enhance the grain size of a polycrystalline film on an amorphous substrate has been previously reported. In this process, ion implantation is used to selectively anorphize the film, and undamaged grains act as seed crystals in a subsequent low-temperature anneal. In this work, a 120 nm polycrystalline silicon film was implanted from three angles with phosphorous at 150°K. The total dose was l.0×l015/cm2 . Transmission electron micrographs after a partial anneal (700°C for 30 minutes) indicate that some crystallites survived implantation due to ion channelling in the (111) plane. After a 60 minute anneal at 700°C, 7 μm grains were observed.
Thin Polymeric Films Produced by Ion Implantation from Frozen Organic Molecules
Authors: Calcagno L. , Sheng K. L. , Foti G. 
Published: March 2011

ABSTRACTThe synthesis of polymeric films under ion bombardment of frozen benzene has been investigated for the dependence of the thickness on the fluence and beam energy of keV proton and argon ions. Chemical analyses have been performed to characterize the films.
Effects of Nitrogen and Helium Ion Implantation on Uniaxial Tensile Properties of 316 SS Foils
Authors: Spitznagel J. A. , Hall B. O. , Doyle N. J. , Jayram Raman , Wallace R. W. , Townsend J. R. , Miller M. 
Published: March 2011

ABSTRACTImplantation of nitrogen into steels is known to affect surface sensitive mechanical properties. Tensile properties of thin foils implanted with either nitrogen or helium at 300 K have been measured. Fluences greater than 1 × 1016 ions/cm2 raise the yield stress and fracture stress and reduce the plastic strain to failure. Both nitrogen and helium give comparable stress-strain responses for equal average concentrations of implanted ions. The mechanical response is discussed in terms of plastic flow of laminated structures and hardening mechanisms. Initial results of atom probe field ion microscopy examinations of nitrogen implanted Fe-15 wt.% Cr-12 wt.% Ni alloy are described.
Industrial Applications of Ion Implantation
Authors: Hirvoney J.K. 
Published: March 2011

ABSTRACTThe use of ion implantation for non-semiconductor applications has evolved steadily over the last decade. To date, industrial trials of this technology have been mainly directed at the wear reduction of steel and cobalt-cemented tungsten carbide tools by high dose nitrogen implantation. However, several other surface sensitive properties of metals such as fatigue, aqueous corrosion, and oxidation, have benefitted from either i)direct ion implantation of various ion species, ii)the use of ion beams to “intermix” a deposited thin film on steel or titanium alloy substrates, or iii)the deposition of material in conjunction with simultaneous ion bombardment.This paper will concentrate on applications that have experienced the most industrial trials, mainly high dose nitrogen implantation for reducing wear, but will present the features of the other ion beam based techniques that will make them appear particularly promising for future commercial utilization.
Friction and Wear Behavior of a Cobalt-Based Alloy Implanted with Ti or N
Authors: Dillich S. A. , Bolster R. N. , Singer I. L. 
Published: March 2011

ABSTRACTDry sliding friction tests and relative abrasive wear measurements were used to investigate the effects of ion implantation on the tribology of a centrifugally cast Co-Cr-W-C alloy. Titanium implantation was found to significantly reduce the friction and wear of the alloy. Auger spectroscopy showed that vacuum carburization of the surface occurred during Ti implantation. Similar Ti and C profiles were seen in both carbide and (Co-rich) matrix phases. The abrasive wear resistance of the alloy decreased as a result of N-implantation. Nitrogen implantation did not reduce the friction during dry sliding, however, a change in the wear mode was observed.
The Mechanical Properties of Si+ and Pb+ Implanted Al
Authors: Madakson P.B. 
Published: March 2011

ABSTRACTCommercially pure Al was implanted with 300 keV Si+ and 200 keV Pb+ to doses of between l011 and 1017 ions/cm2. Changes in friction, wear, oxidation and hardness were investigated. Silicon increased the hardness and wear resistance of Al and significantly decreased friction and the oxidation of the implanted surface. These changes were observed to be almost proportional to the implanted dose. The implantation of Pb+ resulted in a linear increase in hardness and a decrease in surface oxidation with dose. Friction decreased and wear resistance increased but the changes were not dose dependent. The implantation of Si+ did not significantly alter the distribution of impurities, such as Fe and Cu within the Al matrix, but Pb+ resulted in a diffusion of Fe to the implanted surface. Formation of precipitates was observed and the improvements in the surface properties studied are considered to result from precipitation hardening, which involves the impediment of dislocation movement by the precipitates during plastic deformation of the implanted Al.
Wear Behavior of Flat and Graded Profile Boron-Implanted Beryllium
Authors: Kumar K. , Newborn H. , Kant R. 
Published: March 2011

ABSTRACTPin-on-disk tests were performed for comparative friction and wear behavior on flat and graded profile boron implanted beryllium samples. Peak, intended boron concentrations of 10, 20, 30 and 40 atom percent were investigated. Auger Electron Spectroscopy was used to determine the boron concentration as a function of depth. Preliminary work was performed to study the effects of (1) a low temperature (450°C, 1–1/2 hours) heat treatment of the implanted specimens and (2) a change in the pin material. All of the boron implanted beryllium samples showed significant improvement versus unimplanted beryllium and an anodized beryllium surface. Graded samples showed comparable friction coefficients but inferior wear resistance with respect to the flat profile samples.
Enhancement of Ferrous Alloy Surface Mechanical Properties by Nitrogen Implantation
Authors: Pollock John T.A. , Kenny Michael J. , Paterson Peter J.K. 
Published: March 2011

ABSTRACTClarification of the relationship between nitrogen profiles and wear behaviour has been sought by studying nitrogen implanted mild steel. Implant energy and dose were in the ranges 25 – 65 keV and 0.9 − 3 × 1017 1ions cm−2, respectively. Wear characteristics were measured with a ball-on-disc system followed by interferometric
analysis. Nitrogen distributions before and after wear were determined by Auger electron spectroscopy and Rutherford backscattering methods, and compared with wear track profiles. On balance, the data offers qualified support for nitrogen migration at low loads, although nitrogen was not detected for wear depths >2 times the implant depth. Observations of wear on the abrader ball-bearing surface and the role of oxygen in the wear process are reported.
Wear Behavior and Structural Characterization of a Nitrogen Implanted Ti6Al4V Alloy at Different Temperatures
Authors: Martinella R. , Chevallard G. , Tosello C. 
Published: March 2011

ABSTRACTMechanically polished Ti6Al4V samples were implanted with 100 key nitrogen ions to a fluence of 5.1017 ions/cm2 at two different bulk tenneratures: 370°C and 470°C. Wear tests were carried out with a reciprocating slidina tribotester. Structural modifications and wear morphologies were studied by TEM and SEM. 370°C implanted sample showed the same wear behavior as unimplanted ones, while 470°C implanted sample showed better wear resistance because of a TiN hardened layer. Correlations- between microstructural modifications, wear behavior and mechanisms are reported: results agree with the delamination theory. Comparison with ion- and gas-nitrided samples are presented.
Ion Beams and Catalysis
Authors: Cairns J.A. 
Published: March 2011

ABSTRACTIon beam techniques have found increasing application in recent years to a wide variety of disciplines. It is the purpose of this paper to explore their potential in the field of catalysis, concentrating exclusively on solid heterogeneous catalysts. An initial description of the internal structure and external physical form of some typical catalysts is followed by an assessment of the use of ion beams for the preparation and interrogation of both “real” and model catalysts. These techniques are then compared to some of the modern tools used in current catalysis research. It emerges that ion beams can indeed be used to advantage in certain applications, such as detecting light elements selectively; measuring interaction effects between metals and supports in model systems; highlighting surface relaxation effects in metal single crystals; and even, in special circumstances, in synthesising catalysts.
Corrosion behavior of Ni+ -Ion Irradiated NiTi Alloys
Authors: Wang R. , Brimhall J. L. 
Published: March 2011

ABSTRACTCorrosion behavior of Ni+ -irradiated NiTi alloys was studied in chloride solutions, together with unirradiated NiTi material with different surface conditions. Ion irradiation with either 2.5 or 5 MeV Ni+ ions transformed the NiTi surface into an amorphous layer up to 1.5 micrometers thick. Studies of corrosion potential vs. time and polarization behavior indicated a small enhancement of the passivation for the Ni+-irradiated NiTi over the unirradiated NiTi. The unirradiated NiTi with a mechanically polished, coarse surface was susceptible to pitting and crevice corrosion attack in 1 N HCl solution. The homogeneous amorphous structure in the irradiated alloy retarded this type of localized corrosion.
Effect of N-Implantation on the Corrosive-Wear Properties of Surgical Ti-6Al-4V Alloy
Authors: Williams J. M. , Beardsley G.M. , Buchanan R. A. , Bacon R. K. 
Published: March 2011

ABSTRACTThe effects of N-ion implantation on the corrosive-wear properties of Ti-6Al-4V, an alloy used for construction of the femoral component of artificial hip joints in humans, were tested. In corrosive-wear tests designed to simulate pertinent hip-joint parameters, electrochemical corrosion currents were measured for cylindrical samples in saline electrolyte in an arrangement which allowed the samples to be rotated between loaded polyethylene pads simultaneously with the current measurement. To further quantify material removal, Zr markers were ion-implanted into some samples so that, by use of Rutherford backscattering, material removal could be detected by changes in position of the marker relative to the surface. Corrosion currents were greatly reduced by implantation of approximately 20 at. % N, but even implantation of the Zr markers also reduced corrosion currents. The marker experiments confirmed the low rate of material removal for the implanted samples.
Enhancement of Uranium Oxidation Resistance by Molybdenum Implantation
Authors: Kaufmann E. N. , Musket R. G. , Colmenares C.A. , Appleton B. R. 
Published: March 2011

ABSTRACTInitial studies of the oxidation resistance imparted to uranium metal through the implantation of Mo ions have shown that a significantly increased resistance can be achievedfor doses of 5 ×1016/cm2. No enhancement of oxidation resistance was found for doses below 1 ×1016/cm2. We report results of weight-gain measurements, ion-beam analysis, and x-ray diffraction, as well as observations of the way in which the protective implanted layer fails at long exposure times.
Modification of the Hydriding of Uranium using Ion Implantation
Authors: Musket R. G. , Robinson-Weis G. , Patterson R. G. 
Published: March 2011

ABSTRACTThe hydriding of depleted uranium at 76 Torr hydrogen and 130°C has been significantly reduced by implantation of oxygen ions. The high-dose implanted specimens had incubation times for the initiation of the reaction after exposure to hydrogen that exceeded those of the non-implanted specimens by more than a factor of eight. Furthermore, the nonimplanted specimens consumed enough hydrogen to cause macroscopic flaking of essentially the entire surface in times much less than the incubation time for the high-dose implanted specimens. In contrast, the ion-implanted specimens reacted only at isolated spots with the major fraction of the surface area unaffected by the hydrogen exposure.
Sol-Gel Synthesis of YBa2Cu3O7-& Using Yttrium, Barium and Copper Polyether Alkoxide Precursors
Authors: Page Catherine J. , Houk Carol S. , Burgoine Gary A. 
Published: March 2011

ABSTRACTHomogeneous solutions of yttrium, barium and copper 2-(2-methoxy)-ethoxyethoxides in 2-(2-methoxy)ethoxyethanol of appropriate lY:2Ba:3Cu stoichiometry have been prepared and used in sol-gel synthesis of YBa2Cu3O7-δ. To our knowledge, this is the first report of the preparation of a homogeneous solution of yttrium, barium and copper homoleptic alkoxides dissolved only in the parent alcohol. These solutions provide an excellent starting point for sol-gel synthesis of YBa2Cu3O7-° since the metals are mixed on the molecular scale, and because the solutions are stable with no possibility of ligand exchange to give insoluble products. Hydrolysis and careful heat treatment of gels produced from these solutions yield nearly pure tetragonal YBa2Cu3O7-δ at temperatures as low as 725°C. The preparation of these solutions and their characterization by small-angle x-ray scattering measurements and TEM are reported, as well as preliminary data pertaining to their use in the sol-gel synthesis of YBa2Cu3O7-δ.
From Ceramics to Superconductors: Rapid Materials Synthesis by Solid-State Metathesis Reactions
Authors: Treece Randolph E. , Gillan Edward G. , Jacubinas Richard M. , Wiley John B. , Kaner Richard B. 
Published: March 2011

ABSTRACTThe preparation of materials from gas and liquid phase precursor reactions is well documented. However, solid-state precursor routes have remained largely unexplored. This synthetic void led us to develop rapid (< 2 s), solid-state metathesis (exchange) reactions with a very broad range of synthetic applications. An example is the self-propagating reaction:where the Nal is simply washed away with water. Analogous reactions allow the preparation of carbides, suicides, chalcogenides (O, S, Se, and Te), and pnictides (N, P, As, and Sb), of main-group, transition-, and rare-earth metals. These methods can also be exploited to produce mixed-metal and mixed-nonmetal solid solutions.To gain insight into some of the mechanistic factors involved in these reactions, such as initiation, nucleation, and propagation, we have employed a variety of physical characterization methods. This paper will review the range of materials accessible by our synthetic approaches, as well as the control of product crystallinity, phase, and homogeneity through the optimization of reaction conditions.
Characterizations of Sol-Gel Cordierite Precursors
Authors: Chen Yun Fa , Hadigui Saïd El , Vilminot Serge 
Published: March 2011

ABSTRACTCordierite powders were prepared using silicon ethoxide, Mg(NO3).2.6H2O and Al (OBu)2etac (etac = ethylacetoacetate) and conditions of hydrolysis have been checked in order pure a cordierite to be obtained. D.T.A. measurements reveal a stepwise crystallization process with intermediate formation of metastable μ cordierite. Infrared studies allow to follow the evolution of the Si-O-Al network with temperature.
Synthesis of New Compounds by Ion-Exchange Reactions
Authors: Villafuerte-Castrejón M. E. , Aragón-Piña A. 
Published: March 2011

ABSTRACTIon-exchange reactions, particularly with molten salts, are a convenient low temperature route to prepare new materials. Six different complex oxides (KTaO3, K2Ti4O4, NaAlSiO4, Na2Si2O5,ß-NaAlO2and K2Ge4O9) were reacted with different salts (NaCI, KC1, Na2SO4, NaNO3, LiCl and LiNO3) by the ion exchange route with molten salts. In this work, new phases and substitution reactions are reported.
Comparative Study of the Sol-Gel and Metallo-Organic Decomposition (MOD) Processes for the Preparation of Inorganic Materials
Authors: Paz-Pujalt Gustavo R. , Nie W. , Lurin C. 
Published: March 2011

ABSTRACTSol-Gel processing and Metallo-Organic Decomposition are contrasted from the thermodynamics and chemical reactivity points of view. Differences and similarities on precursor requirements, processing characteristics, processing intermediates, and product formation pathways are outlined. Some specific examples are presented and their reaction thermodynamics are compared. Some conclusions regarding thermo-dynamic versus kinetic control are drawn from these examples.
Rheology of Zirconia-Alumina Gelcasting Slurries
Authors: Bleier A. , Omatete O. O. , Westmoreland C. G. 
Published: March 2011

ABSTRACTThe rheology of zirconia-alumina composite slurries for gelcasting was studied in order to maximize the solids loading. The viscosity and yield stress were controlled by adjusting the pH. This approach allows the solids loading to be maximized for the gelcasting of near-net-shape composites. A strong correspondence exists among the rheological behavior, the surface charge on the particles, colloidal stability, and the maximum solids loading. The best pH conditions for gelcasting composites depends on the specific binary composition.
Novel Precipitation Route to Silica Grain
Authors: Simms Barbara , Gallo Tom 
Published: March 2011

ABSTRACTWe describe a novel precipitation route to silica grain that lies in the interface between sol-gel and Stöber-type silica. The use of acetic acid as a catalyst for TEOS hydrolysis provides access to a precipitation window in which partially hydrolyzed TEOS and TEOS monomer, when reacted with aqueous ammonia, combine to form pumice-like silica particles in up to 90% yield as SlO2. Precipitated particles exhibit narrow particle size distributions that may be controlled for average particle sizes from 50µ to 400 µ. SEM micrographs show that the particles are agglomerates of small particles, which is consistent with the high degree of observed macroporosity.
Stability of Aqueous Suspensions of High Surface area Zirconia Powders in the Presence of Polyacrylic Acid Polyelectrolyte
Authors: Boutz Michel M. R. , Olde Scholtenhuis R. J. M. , Winnubst A. J. A. , Burggraaf A. A. J. 
Published: March 2011

ABSTRACTIn this paper results of efforts to prepare stable aqueous suspensions of high surface area (> 100 m2 /gr) yttria stabilized tetragonal zirconia powders are presented using a low molecular weight ammonium polyacrylic acid deflocculant. Zetapotentials, viscosities, agglomerate sizes and sedimentation volumes have been measured to find the optimum pH and deflocculant concentration. It has been found that the optimum pH-value coincides with the pH at which the polyacrylic acid is fully dissociated. Using deflocculant concentrations below the optimum value leads to a highly unstable system, while concentrations above the optimum value influence the stability in a much weaker way.
Production of Sols from Aggregated Titania Precipitates
Authors: Bartlett John. R , Woolfrey James L. 
Published: March 2011

ABSTRACTTitania and titania/zirconia sols, with solids loadings exceeding 1000 g dm3, have been prepared on a 10 kg scale by chemical methods involving the hydrolysis of an appropriate mixture of alkoxides, followed by peptisation with dilute nitric acid. The rate of peptisation of the hydrolysates was determined by static light-scattering and photon-correlation spectroscopy, enabling the hydrodynamic radius, the radius of gyration and the fractal dimension of colloidal species to be monitored as a function of peptisation time.The peptisation kinetics were influenced by a range of factors including the initial solids loading, the acid concentration, the reaction temperature and the age of the alkoxide hydrolysate. Hydrolysate peptisation is first order with respect to concentration of acid and exhibited a non-integer reaction rate order (complex mechanism) with respect to solids concentration. Sols produced from freshly-precipitated hydrolysate peptised at a faster rate than aged precipitates but slowly re-aggregated after peptising, yielding “equilibrium” aggregate sizes often exceeding 100 nm. This effect was not observed in sols produced from aged hydrolysate. These differences are interpreted using DLVO theory.