bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of Near Surface Structure and Composition for High Dose Implantation of Cr+ into Si
Authors: Namavar F. , Budnick J. I. , Hayden H. C. , Otter F. A. , Patarini V. 
Published: March 2011

ABSTRACTThe dependence of the implanted layer composition on total dose, dose rate and target chamber environment for Cr+ implanted Si have been studied by means of Rutherford Back Scattering (RBS) and Auger Electron Spectroscopy (AES). Implantation of Cr+ for doses up to 2 × 1018 ions/cm2 and a fixed dose rate and energy were carried out in an ultra high vacuum (UHV) system as well as in a diffusion pumped vacuum (DPV) system. For the former, the maximum Cr concentration was about 42%. On the other hand, implantation of Cr in a DPV system resulted in a much higher peak concentration (86%) and retention.Both the RBS and AES results positively demonstrate the existence of extensive surface carbon for a Si-rich surface and a chromium oxide layer for the Cr-rich surface. This result suggests that the interaction of oxygen or carbon occurs preferentially and depends on the surface composition.No surface compositional variation could be observed by the RBS experiments for Cr implanted in a UHV system for different dose rates. In contrast, for implantation in a DPV system, higher concentrations can be achieved for lower dose rates.
Modification of μm Thick Surface Layers Using keV Ion Energies
Authors: Rehn L. E. , Lam N. Q. , Wiedersich H. 
Published: March 2011

ABSTRACTRoot-mean-square diffusion distances for both vacancy and interstitial defects in metals can be very large at elevated temperatures, e.g. several μm's in one second at 500°C. Consequently, defects that escape the implanted region at elevated temperature can produce compositional and microstructural changes to depths which are much larger than the ion range. Because of the high defect mobilities, and of the fact that diffusion processes must compete with the rate of surface recession, the effects of defect production (ballistic mixing), radiation-enhanced diffusion and radiation- induced segregation become spatially separated during ion bombardment at elevated temperature. Results of such experimental studies in a Cu-Ni alloy are presented, discussed and compared with predictions of a phenomenological model. Contributions to the subsurface compositional changes from radiation-enhanced diffusion and radiation- induced segregation are clearly identified.
Ion Beam Modification of Ceramics
Authors: Mchargue C. J. , White C. W. , Appleton B. R. , Farlow G. C. , Williams J. M. 
Published: March 2011

ABSTRACTAlterations to the structure and properties of ceramics are complex due to the range of bonding types encountered and the necessity for maintaining local charge balance. Ion damage can occur as a result of ionizing effects as well as displacement collisions. Ion species, implantation temperature, implantation energy, and the specific bonding characteristics of the host are important parameters in determining the structure and properties of implanted ceramics. Some of these effects will be illustrated for Al2O3 implanted with chromium or zirconium and silicon carbide implanted with chromium.
Changing the Indentation Behaviour of MgO by Ion Implantation
Authors: Burnett P.J. , Page T.F. 
Published: March 2011

ABSTRACTCleaved {100} MgO single crystal surfaces have been implanted with 300keV Ti+and Cr+ ions to doses in the range 10 16 −1018 ions cm−2. Localised plasticity and fracture behaviour has been investigated using microhardness indentation tests at loads of between 10gf and 500gf.Significant surface hardening has been observed at lower doses with amorphisation related softening occurring at higher doses. Post-implantation heat treatments produce precipitation reactions with associated hardness changes.
Synthesis of Hard Si-C Composite Films by Ion Beam Irradiation of Polymer Films
Authors: Venkatesan T. , Wolf T. , Allara D. , Wilkens B. J. , Taylor G. N. , Foti G. 
Published: March 2011

ABSTRACTWe propcoe a novel technique to convert polymer films into useful inorganic films by ion beam irradiation. Along the track of an ion the polymer is dissociated into smaller fragments. volatile fragments diffuse through the film and escape. Any element which is not removed in the form of volatile species is subsequently enriched with respect to the other elements. We demonstrate this effect in a polymer poly(dimethylsilylene-co-methylphenylsilylene), which initially has a C:Si ratio of 45:1. Upon irradiation with 2 MeV Ar+ ions at a dose of 1015 ions/cm2 the C:Si ratio changes to 3.4:1 as verified by Rutherford backscattering spectrometry. We believe that the effect of the ion beam irradiation is to produce more Si-C bonds at the expeme of the C-H and Si-Si bonds, with ≲10% of the original hydrogen being present in the film at high doses. The loss of the H atoms is further confirmed by a nuclear reaction technique. The IR spectra of the film as a function of the irradiation dose shows a progressive loss of fine molecular features with significant increase of the refractive index. The IR spectrum at the high doses appears to be due to a mixture of various Si and C bonds. However, the irradiated films are very hard and scratch resistant (knoop value ≳1300) suggesting an increase in the number of silicon carbide bonds
Depth Profiling of Hydrogen in Ion-Implanted Polymers
Authors: David Carlson J. , Pronko Peter P. , Ingram David C. 
Published: March 2011

ABSTRACTDepth profiling of hydrogen in polymeric materials poses special problems. Backscattering methods are ruled out because of kinematics. Nuclear reaction methods are undesirable because small reaction cross sections necessitate large fluences of high mass projectiles and result in unacceptable levels of radiation damage. We have used a helium-induced proton-recoil technique with 3 MeV 4He particles to measure the hydrogen distribution in pristine and ion-implanted polyvinylidene fluoride (PVDF) films. The incident 4He particles stopped in the 25 micron PVDF films while the recoiling protons were detected after passing through the polymer film. Large changes in the hydrogen content of PVDF films implanted with modest fluences of 6 MeV carbon, oxygen and nickel ions were observed.
Ion Beam Mixing Effects in Au-Fe and Pt-Fe Thin Bilayers
Authors: Battaglin G. , Carnera A. , Celotti G. , Della Mea G. , Kulkarni V.N. , Lo Russo S. , Mazzoldi P. 
Published: March 2011

ABSTRACTMixing effects induced by Kr++ bombardment in the Au-Fe and Pt-Fe metallic systems have been studied by Rutherford backscattering and X-ray diffraction techniques. The mixed amount of Fe atoms shows a linear dependence on the square root of the Kr do se for both systems. The induced mixing appears more efficient for the Pt-Fe with respect to the Au-Fe system. In the case of Pt-Fe mixing is much more efficient when the initial bilayer structure has Pt on the top. The X-ray diffraction analysis reveals the formation of an extended solid solution of Fe in Pt, having the Fe40 Pt60 composition.
Development of New Materials by Ionized-Cluster Beam Technique
Authors: Takagi T. 
Published: March 2011

ABSTRACTIn the Ionized-Cluster Beam (ICB) technique, deposition by macroaggregates consisting of 500 to 2000 atoms loosely coupled together involves low ratios of charge to mass. Consequently, high mass density beams at low equivalent energy per atom in an optimum range for film formation can be transported without problems due to space charge repulsion forces and deposition onto insulating substrates is easily possible due to low accumulation of ion charge. The presence of ionic charge has great influence upon film formation mechanisms in spite of low content of ions in the total flux. Also, because of the kinetics of cluster breakup upon impact, enhancement of migration of adatoms upon a substrate surface can be achieved by increasing the acceleration voltage. It is possible to control the mechanical, crystallographic, optical and magnetic properties of films over three dimensions by variation of acceleration voltage or ion content in the total flux. Films of many materials have been formed at low temperatures with well-controlled characteristics. Among examples of interest are included metal and semiconductor material films for functional devices and VLSI applications, intermetallic compound films for magnetic or thermoelectric uses and organic material films. Results suggest that ICB offers exceptional potential for applications involving formation of new materials.
Ion Beam Irradiation of Metal Films on SiO2
Authors: Clark G. J. , Baglin J. E. E. , d'Heurle F. M. , White C. W. , Farlow G. , Narayan J. 
Published: March 2011

ABSTRACTIon beam irradiation of metal film/SiO2 interfaces causes reactions when the metals are those chemically capable of reducing SiO2. These reactions result in the formation of metal rich silicides in the region of the interface and an increase in the adhesion of the film to the substrate. For other nonreactive metals ion irradiation causes lateral transport of metal atoms resulting in the formation of an island structure. The results obtained by ion irradiation are compared with previous studies of high temperature thermal processing of metal films on SiO2.
Magnetoreflection of Ion-Implanted Bismuth
Authors: Kunoff E. M. , Elman B. S. , Dresselhaus M. S. 
Published: March 2011

ABSTRACTBi single crystals have been implanted with isoelectronic ions (As, Sb and Bi) and the electronic structur of these implanted materials has been studied using the magnetoreflection technique. Since the ion penetration depth and optical skin depths are of roughly the same magnitude, this technique provides a sensitive test for implantation-induced changes in the electronic structure. Explicitly, the magnetoreflection spectra show changes in lineshape, resonant frequency and in some cases the introduction of Landau level transitions forbidden in unimplanted bismuth. In particular, implantation-induced changes in the resonance lineshapes indicate an increase in plasma frequency as either the fluence of the implants or the ion size is increased. Further analysis of the data shows that the Lax model, which accounts for the magnetoreflection spectra of unimplanted bismuth, is equally applicable to bismuth implanted with isoelectronic ions. Our results yield measurable changes in the L-point band gap and smaller relative changes in the band parameter combination Eg/m* . The mechanism responsible for these changes in the electronic structure of bismuth is suggested.
Enhancement in Adhesion of Pt Films on Ceramics by Helium Ion and Electron Irradiation, and a Study of their Electrochemical Behaviour.
Authors: Sood D.K. , Bond P.D. , Badwal S.P.S. 
Published: March 2011

ABSTRACTThe adhesion of Pt films (10–330nm thick) sputter deposited on prepared substrates of yttria stabilized zirconia (YSZ) and alumina has been observed to be remarkably enhanced after irradiation with 2 MeV He++ ions and 5–30 keV electrons. The adhesion enhancement has been studied as a function ot beam energy, dose and film thickness. Thermal stability of adhesion enhancement and of the microstructure of ‘stitched’ films has been investigated. The electrochemical behaviour of ‘stitched’ Pt electrodes on YSZ has been studied by complex impedance spectroscopy.
Ion Implantation into Nb/NbO/PbAuIn Josephson Tunnel Junctions
Authors: Clark G. J. , Raider S. I. 
Published: March 2011

ABSTRACTBoron ions were implanted into completed planar and edge Nb/Nb oxide/PbAuIn Josephson tunnel junctions to directly trim the Josephson pair currents, Io. The implantation caused an increase in Io and in the junction subgap conductance and a decrease in the junction energy gap. For a fixed junction fabrication procedure, the variations were observed to be monotonic with 11B implant dose. Optimum trimming was found when the 11B ions were implanted such that the peak in the depth distribution occurred at the tunnel barrier. The implantation caused an increase in Io and in the junction subgap conductance and a decrease in the junction energy gap. The implanted junctions are stable at 80°C and under storage.
Tribomechanical Properties of Ion Implanted Metals
Authors: Singer Irwin L. 
Published: March 2011

ABSTRACTA review of tribomechanical studies supported by surface analysis finds ion implantation capable of increasing the sliding wear resistance of ion implanted metals in two ways. First, it can reduce friction by modifying the surface composition (e.g. Ti+ into steel) or by promoting the growth of low friction oxide layers (e.g. N into Ti). Second, it can modify the subsurface composition and structure to resist fracture and debris formation. These modifications harden the surface, change its work-hardening behavior and/or increase residual stresses. Microindentation hardness measurements indicate that many but not all of the wear resistant surfaces are hardened by implantation; thus, surface hardness is a contributing but not necessarily a controlling factor in wear resistance. These mechanisms of wear reduction and the chemical and microstructural modifications responsible for them are discussed. Evidence for wear reduction through the migration of N during wear is critically reviewed. It is concluded that the principal benefit of ion implantation is to prevent or delay the formation of wear particles, thereby changing the wear mode during run-in and permitting metals to reach load-carrying capacities up to their elastic limits.
Hardness as a Measure of Wear Resistance
Authors: Oliver W.C. , Hutchings R. , Pethica J.B. , Singer I.L. , Hubler G.K. 
Published: March 2011

ABSTRACTOne measure of the surface mechanical properties of materials can be obtained through microhardness data. The success of microhardness in predicting the improvements in wear resistance of ion implanted metals has been mixed. In this paper the cases of N implantation into 304 S.S. and Ti implantation into 52100 bearing steel will be examined. Microhardness data indicates little or no hardness changes whereas large wear rate changes are observed. From these two examples it is clear that the wear mechanism, the chemical nature of the surface, the ductility, and the toughness can be more important than the hardness changes.
Modeling of High Fluence Titanium Ion Implantation and Vacuum Carburization in Steel
Authors: Farkas D. , Singer I. L. , Rangaswamy M. 
Published: March 2011

ABSTRACTConcentration vs. depth profiles have been calculated for Ti and C in 52100 Ti-implanted steel. A computer formalism was developed to account for diffusion and mixing processes, as well as sputtering and lattice dilation. A Gaussian distribution of Ti was assumed to be incorporated at each time interval. The effects of sputtering and lattice dilation were then included by means of an appropriate coordinate transformation. C was assumed to be gettered from the vacuum system in a one-to-one ratio with the surface Ti concentration up to a saturation point. Both Ti and C were allowed to diffuse. A series of experimental (Auger) concentration vs. depth profiles of Ti implanted steel were analyzed using the above-mentioned assumptions. A best fit procedure for these curves yielded information on the values of the sputtering yield, range and straggling, as well as the mixing processes that occur during the implantation. The observed values are in excellent agreement with the values predicted by existing theories.
Microstructures of Stainless Steels Exhibiting Reduced Friction and Wear After Implantation with Ti and C
Authors: Follstaedt D. M. , Yost F. G. , Pope L.E. 
Published: March 2011

ABSTRACTImplantation of Ti and C into stainless steel discs of Types 304, 15–5 PH, Nitronic 60 and 440C has previously been reported to reduce wear depths by up to ∼ 85% and friction by ∼ 50% in unlubricated pin-on-disc tests. Our earlier studies relating microstructure to friction and wear results in Type 304 are first summarized; these indicate that the improvements in the surface mechanical properties are due to an amorphous surface layer, similar to the amorphous layer observed in pure Fe implanted with Ti and C. We have now examined the other three implanted steels and found similar amorphous layers. These results strongly suggest that the amorphous surface alloy is responsible for reduced friction and wear in all the steels.
Friction and Wear Reduction of 440C Stainless Steel by Ion Implantation
Authors: Pope L. E. , Yost F. G. , Follstaedt D. M. , Picraux S.T. , Knapp J. A. 
Published: March 2011

ABSTRACTFriction and wear tests on ion-implanted 440C stainless steel discs have been extended to high Hertzian stresses (≤ 3150 MPa). Implantation of 2 × 1015 Ti/mm2 (180–90 keV) and 2 × 1015 C/mm2 (30 keV) into 440C reduces friction (∼40%) and wear (> 80%) for Hertzian stresses as large as 2900 MPa, stresses which significantly exceed the yield strength of 440C (∼1840 MPa). Implantation of 4 × 1015 N/mm2 (50 keV) into 440C reduces friction slightly (∼25%) for Hertzian stresses > 1840 MPa but provides little or no reduction in wear. The amount of Ti remaining in the wear tracks correlates with the reductions in friction and wear. The implantation of Ti and C produces an amorphous surface layer which is believed to reduce friction and wear, whereas N implantation is expected to produce hard nitride particles which probably do not modify the hardness of 440C (KHN = 789) significantly.
Friction, Wear and Deformation of Soft Steels Implanted with Ti and N
Authors: Singer I.L. , Jeffries R.A. 
Published: March 2011

ABSTRACTFriction and wear measurements were performed with a hardened steel ball sliding against unhardened steels (AISI 10184 304 and M2) implanted with either N+ or Ti+ or both N+ Ti+ ions. Dry and lubricated sliding studies found that: Ti-implantation reduced friction and thereby delayed wear; N-implantation did not reduce friction but delayed wear by increasing the resistance of the surface to shear; and dual implants of N+ + Ti+ showed effects of both implants. Auger sputter depth profiles found the 1018 and M2 surfaces enriched in implanted N and bulk C. No evidence of N migration could be found in heavily deformed surfaces.
Electrical Resistivity of Multilayers During Ion Beam Mixing
Authors: Grilhe J. , Riviere J.P. , Delafond J. , Jaouen C. , Templier C. 
Published: March 2011

ABSTRACTA new approach is developed, employing “in situ” electrical resistivity measurements, as a tool to study ion beam mixing of evaporated metal-metal multi or bilayers. The electrical resistivity variations measured continuously during the ion bombardment exhibit a monotonical increase and a tendency toward a saturation process allowing to detect precisely the total mixing of the film. The volume fraction of intermixed atoms can be determined within the framework of a simple conduction model. Experimental results are given in the case of Fe-Al and Al-Ag multilayers.
Wear Improvement in Ti-6Al-4V by Ion Implantation
Authors: Vardiman R.G. 
Published: March 2011

ABSTRACTThe friction and wear of Ti-6Al-4V are found to be sharply reduced by carbon implantation followed by heat treatment. Optimum wear resistance is developed at 400° C, at which the microstructure of the implanted layer shows a dense array of TiC precipitates up to 60 nm in size. The implanted layer in this case is worn through in a few thousand cycles of the ball on disc test, but by implanting at two energies to achieve a deeper carbide layer, negligible wear was found even after 20,000 cycles. No wear improvement was found for nitrogen implantation.
Ion Implanted Ti-6Al-4V
Authors: Oliver W. C. , Hutchings R. , Pethica J. B. , Paradis E. L. , Shuskus A. J. 
Published: March 2011

ABSTRACTTitanium and many of its alloys show very poor wear resistance considering their hardness. This together with high thermodynamic driving forces to form very hard compounds between titanium and nitrogen or carbon made titanium based alloys obvious candidates for ion implantation. In this paper the effects of similar implanted concentration profiles of nitrogen and carbon in two titanium alloys are compared. The wear behavior of pin on disk wear tests are reported along with the ultramicrohardness of the four samples.
Effect of Cr+ Implantation on the Thermal Oxidation of Ta
Authors: Grabowski K.S. , Gossett C.R. 
Published: March 2011

ABSTRACTCr+ implantation of Ta was undertaken in an attempt to improve oxidation resistance at temperatures between 500 and 750°C, and for oxidation times up to l00h. Samples were implanted with 1.5×1017 Cr+/cm2 at 150 keV, and compared to samples implanted with 1×l016 or 1×1017 Ta+/cm2 at 145 keV to evaluate the role of physical effects from ion implantation. Following oxidation, samples were examined using helium and proton backscattering, electron and optical imaging techniques, and auger electron spectroscopy. Improved resistance to oxidation was observed in Cr+-implanted samples oxidized at 500°C for up to l00h, and at 600°C for about lh. However, some local breakdown occurred in these samples and no protection at all was observed at 750°C. Reasons for this breakdown are discussed and alternate approaches for improving oxidation resistance using ion implantation are proposed.
Recoil Implantation of Ito thin Films on Glass Substrates
Authors: Rabin B. H. , Harbison B. B. , Shatynski S. R. 
Published: March 2011

ABSTRACTIndium-Tin Oxide (ITO) heat mirror films implanted into window glass were obtained by post annealing of argon irradiated coatings of In-5w/o Sn produced by reactive evaporation in oxygen. Characterization of coatings has been carried out using TEM and AES. Optical properties have also been evaluated. The production of acceptable thin films requires low energy deposition rates during ion bombardment. This places a limit on the extent of film-substrate mixing, which is required if increased film lifetimes are to be realized.
High Energy Ion Beam Mixing in Al2 O3
Authors: Lewis M. B. , Mchargue C. J. 
Published: March 2011

ABSTRACTThe ion beam mixing technique has been employed to mix metal atoms into the surface layers of Al2O3. Ion beams of Fe+ and Zr+ in the 1 to 4 MeV energy range were used to irradiate Al2O3 specimens on the surfaces of which films of chromium or zirconium had been evaporated. Some specimens were irradiated at elevated temperatures of 873 or 1173 K. Rutherford backscattering (RBS) and channeling methods were used to measure the metal atom depth profiles near the surface. Analyses of the backscattering data included binary collision calculations using the codes TRIM and MARLOWE. The significance and limitations of high energy (>1 MeV) beams for ion beam mixing experiments is discussed. Evidence was found for radiation enhanced diffusion and/or solubility of zirconium and chromium in Al2O3 at 873 K.
Preparation of Strontium Titanate Powders by Decomposition of Polymeric Precursors
Authors: Peschke S. L. , Ciftcioglu M. , Doughty D. H. , Voigt J. A. 
Published: March 2011

ABSTRACTThe effects of substituting poly(acrylic acid), PAA, and mucic acid for citric acid in the standard Pechini powder synthesis process was studied. Strontium titanate was chosen as the model system for this study. Powders were prepared from precursor solutions in which PAA (average molecular weight = 2,000 and 5000) was substituted for citric acid (up to 70% by weight), and with reduced weight of total organic reagents (50% reduction). The powders prepared with a 30% substitution of PAA for citric acid produced weakly agglomerated submicron particles after calcining. These powders contained a larger fraction of weak agglomerates than the powders prepared by the original Pechini process. As such, the PAA derived powder could be easily fractionated and dispersed with greater than 70% of the calcined powder having particle sizes less than 0.5 μm