Browsing by Subject "Ion implantation"
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Item Friction and wear behaviour of implanted AISI 316L SS and comparison with a substrate(2002) Dogan H.; Findik F.; Morgul O.Ion implantation creates alterations in surface composition or morphology of solids which yield to a modification of physical and especially mechanical properties; such as hardness and modulus of elasticity. The aim of this study is to focus on the friction and wear behaviour of N2 and Zr implanted and TiN coated 316L stainless steel and compare with a substrate. Particularly, stainless steels were of interest, because they often display a poor tribological behaviour, which can be improved when they are hardened by incorporating N2, TiN and Zr and forming a hardened surface zone. The present implantations were shown to improve the friction coefficient as well as the wear resistance of the stainless steel surface. © 2002 Elsevier Science Ltd.Item Luminescence characterisation of defects in pld alumina and copper implanted silica(2002) Wu Z.; Türkler A.; Brooks R.; Hole D.E.; Townsend P.D.; Köster S.F.; Kurt K.; Gonzalo J.; Suarez-Garcia A.Luminescence is reported for alumina and Al2O3:Cu films grown by pulsed laser deposition and is contrasted with luminescence from Cu ion implanted silica. The implanted samples display numerous emission bands with at least two associated to charge states or the Cu ions. The relative band intensities are altered by thermal treatments. In the case of the thin films the signals are sensitive to the growth conditions and show evidence for trapped Ar nanoparticles, from argon used as a background gas during film growth. Thus in both thin film and ion implanted material the luminescence offers a route to monitor the state of the defects and the copper impurity ions. © 2002 Published by Elsevier Science B.V. © 2002 Elsevier Science Ltd. All rights reserved.Item A simple method for calculating the number of atoms in ion implanted samples from the RBS yield(Association for Scientific Research, 2004) Can N.; Belik H.G.A simple method that computes the number of atoms in implanted samples from the integral of the elastic backscattering yield, using a pocket calculator, is represented. The energy dependence E2, of the Rutherford law and the screening of the nuclear charge by the electron cloud is considered. The method is based on the assumption that the stopping power is a linearly decreasing function of the energy in the range from 1.4 MeV to 2MeV. The total yield can be integrated analytically, and the number of atoms in the sample can then be ascertained by an iteration procedure that can be accomplished with a scientific pocket calculator. The results obtained are compared with the values obtained using the computer simulation code for RBS spectra RUMP.Item High fluence effects on ion implantation stopping and range(2005) Selvi S.; Tek Z.; Öztarhan A.; Akbaş N.; Brown I.G.We have developed a code STOPPO which can be used to modify the more-widely used ion implantation codes to more accurately predict the mean nuclear and electronic stopping power, preferential sputtering and range of heavy ions in monatomic target materials. In our simulations an effective atomic number and effective atomic mass are introduced into conveniently available analytical stopping cross-sections and a better fitting function for preferential sputtering yield is carefully evaluated for each ion implantation. The accuracy of the code confirmed experimentally by comparison with measured Rutherford backscattering spectrometry (RBS) concentration profiles for 130 keV Zr ions implanted into Be to fluences of 1 × 1017, 2 × 10 17 and 4 × 1017 ions/cm2. We find a steady increase in the mean nuclear and electronic stopping powers of the target; the increase in nuclear stopping power is much greater than the increase in electronic stopping power. © 2004 Elsevier B.V. All rights reserved.Item Optical properties and luminescence of metallic nanoclusters in ZnO:Cu(2005) Karali T.; Can N.; Valberg L.; Stepanov A.L.; Townsend P.D.; Buchal Ch.; Ganeev R.A.; Ryasnyansky A.I.; Belik H.G.; Jessett M.L.; Ong C.Copper nanoparticles have been formed in a zinc oxide (ZnO) substrate by Cu implantation at 160 keV. The implant layer shows amorphised behaviour as monitored by the RBS data and optical absorption indicates the surface plasmon resonance peak characteristic of copper nanoparticles. There is nonlinear optical absorption from the Cu nanoparticles. There are numerous changes in the luminescence responses which include a variety of green and yellow emission bands. During excitation there were changes in the cathodoluminescence intensity and lifetime influenced by the surface events, including some unusual features, which may be considered in terms of interactions with surface water and ice. Radioluminescence signals oscillate between the normal emission bands and the wide red line emission from free Zn. Overall ZnO is, therefore, an unexpectedly interesting host for dispersed Cu nanoparticles, not least because the optical features may be compatible with the semiconductor aspects of ZnO. © 2005 Elsevier B.V. All rights reserved.Item Enhanced biocompatibility of GPC by silver ion implantation(2005) Zimmerman R.; Gürhan I.; Muntele C.; Ila D.; Özdal-Kurt F.; Sen B.H.Biocompatible Glassy Polymeric Carbon (GPC) is used for artificial heart valves and in other biomedical applications. Although it is ideally suited for implants in the blood stream, tissue that normally forms around the moving parts of a GPC heart valve sometimes loses adhesion and creates embolisms downstream. Here we compare silver ion implantation and silver deposition, each of which strongly inhibits cell attachment on GPC. Inhibition of cell adhesion is a desirable improvement to current GPC cardiac implants. In vitro biocompatibility tests have been carried out with model cell lines to demonstrate that traces of silver can favorably influence the surface of GPC for biomedical applications. © 2006 Materials Research Society.Item Metal vapour vacuum arc ion implantation facility in Turkey(2005) Öztarhan A.; Brown I.; Bakkaloglu C.; Watt G.; Evans P.; Oks E.; Nikolaev A.; Tek Z.A vacuum arc ion source based metal ion implantation facility is built and in operation at TUBITAK (The Scientific and Technical Research Council of Turkey), Izmir, Turkey and a surface modification research and development program is being carried out here. The system is similar to the one in Lawrence Berkeley Laboratory, which was first built and developed by Brown et al. The broad-beam ion source can be repetitively pulsed at rates up to ∼50 pulses per second and the extracted ion beam current can be up to ∼1 A peak or ∼10 mA time averaged. The ion source extraction voltage can be increased up to 110 kV. Additionally, mixed metal and gas ion beams were generated by a magnetic field, which was obtained through a magnet coil located in front of anode plate and by adding gas in the discharge region. This modified system was used to form buried layers of mixed metal-gas species such as Ti+N (on 316 SS and Ti alloy samples) and Zr and W (316 SS and Ti alloy samples, respectively) of which their hardness, coefficient of friction and wear volumes were measured and their RBS results were obtained. The anodic electrochemical tests showed that the corrosion resistance of Ti implanted 304 SS samples was increased with the dose. Micro structures of Ti implanted surfaces of 304 SS samples were examined with SEM before and after the corrosion tests and the results showed that the pittings were formed mostly in the areas where implanted Ti concentration was less. Recently, the system is equipped with TOF for measuring the charge state distribution of ions. R&D work is planned for the purpose of forming tribologically enhanced materials for industrial applications by using ion implantation, PVD coating, plasma nitriding and their combinations. The results showed that the hardness and performance of ion implanted (with various metals and N) PVD coated cutting inserts increased remarkably. The use of ion implantation techniques in modifying the properties of textile and other materials and optimising the performance of textile and other industrial machine parts and tools is also being investigated and some of the results are presented in this work. © 2004 Elsevier B.V. All rights reserved.Item Optical properties of Cu implanted ZnO(2006) Cetin A.; Kibar R.; Ayvacikli M.; Can N.; Buchal Ch.; Townsend P.D.; Stepanov A.L.; Karali T.; Selvi S.Nanoparticles of Cu have been made in zinc oxide crystals by ion implantation. The Cu ions were implanted at 400 keV into the (0 0 0 1) face of a single crystal. After implantation and after post-irradiation annealing there are numerous changes in the luminescence responses which include a variety of green and yellow emission bands. Following annealing at temperatures up to 1000 °C a green luminescence near 525 nm was observed which has been associated with the isolated Cu ions. The changes between as implanted and annealed luminescence signals suggests that the implants generate clustering or nanoparticle formation of Cu but anneals dissociate them. © 2006 Elsevier B.V. All rights reserved.Item Investigating the Applicability of Metal Ion Implantation Technique (MEVVA) to Textile Surfaces(2006) Öktem T.; Özdogan E.; Namligöz S.E.; Öztarhan A.; Tek Z.; Tarakçioglu I.; Karaaslan A.Polyethylene terephalate (PET) samples were modified by Cu, C, Ti, and Cr implantation using a metal vapor vacuum arc (MEVVA) implanter. The ions were implanted at an accelerating voltage of 30 kV with a dose ranging from 1 × 1014 to 1 × 1017 ions/cm2. In the first part of this study, Cu ions were implanted to improve the electrical properties of PET woven fabrics, and in the second part, C, Ti and Cr ions were implanted to enhance the mechanical properties of PET membrane fabrics. After implantation, the results showed that the half-charge decay time of implanted fabric lessened to milliseconds, and the friction coefficient and wear loss values decreased significantly. The surface morphologies of the samples were examined by scanning electron microscopy and atomic force microscopy. The changes in chemical structure were observed by IR spectra. © 2006, SAGE Publications. All rights reserved.Item Sliding wear behaviour of Zr-ion-implanted D3 tool steel(2007) Saklakoglu N.; Saklakoglu I.E.; Ceyhun V.; Monteiro O.R.; Brown I.G.The wear and friction characteristics of zirconium-ion-implanted AISI D3 tool steel have been investigated using pin-on-disc methods. Ion implantation was carried out using a vacuum-arc-based ion implanter to form multicharged zirconium ion beams at a mean ion energy of 130 keV, and the implantation doses investigated were approximately 3.6×1016, 5×1016 and 1×1017 ions cm-2. It was found that Zr implantation decreased both the wear and the coefficient of friction. The beneficial effects of Zr implantation in terms of associated Auger electron spectroscopy, Rutherford backscattering spectroscopy and scanning electron microscopy microprobe analyses are described. © 2006 Elsevier Ltd. All rights reserved.Item A comparative study of Ti + N and W ion implantation into Ti-6Al-4V alloy(2007) Tek Z.; Öztarhan A.; Selvi S.The effect of Ti + N hybrid ion implantation and W ion implantation at a dose of 1 × 1017 ions/cm2, and 50 kV and 40 kV extraction voltage on mechanical properties of Ti-6Al-4V samples was studied. Mechanical tests have shown that the friction coefficient decreased with both Ti + N and W ion implantations. It was observed that the Ti + N hybrid ion implanted samples gave better results compared to those of the W ion implanted ones. The results of wear tests showed that both Ti + N hybrid and W ion implanted samples had much better wear resistance compared to unimplanted samples. Hardness values for Ti + N hybrid ion implanted and W implanted samples were much higher than those for unimplanted ones. Ti + N and W ions charge state distributions were measured using time of flight spectrometry. W concentration profiles were obtained by Rutherford backscattering spectrometry. These and the range distribution of ions in implanted and unimplanted samples were evaluated using TRIM and STOPPO programs [S. Selvi, Z. Tek, A. Oztarhan, I. Brown, N. Akbaş 'High fluence effects on ion implantation stopping and range', Nuclear Instruments and Methods in Physics Research B 229 (2005) 60-64; J.F. Ziegler, J.P. Biersack, U. Littmark, (Pergamon, New York, 1985); also http://www.SRIM.org] and the results were compared with the experimental data. © 2007 Elsevier B.V. All rights reserved.Item The life of WC-Co cutting tools treated by plasma immersion ion implantation(2007) Saklakoglu I.E.; Saklakoglu N.; Ceyhun V.; Short K.T.; Collins G.In this study, the tool life of plasma immersion nitrogen-implanted cutting inserts while machining AISI 4140 steel has been investigated. The implantation time was 5 h and the temperature was in the range 320-520 °C. Implantation dose was ∼2×1018 ions cm-2 for all treatments. Surface topography of the implanted surfaces was obtained from atomic force microscopy. Results of the turning tests are discussed in terms of tool life (flank wear) and surface roughness of the workpieces. The results show that plasma immersion nitrogen implantation increased tool life by about 85%. © 2006 Elsevier Ltd. All rights reserved.Item A comparative study of single and duplex treatment of martensitic AISI 420 stainless steel using plasma nitriding and plasma nitriding-plus-nitrogen ion implantation techniques(2007) Çetin A.; Tek Z.; Öztarhan A.; Artunç N.Martensitic AISI 420 is a high chromium mold steel which is suitable for tools for molding corrosive plastics. In this study, micro-pulsed plasma nitriding and plasma nitriding + nitrogen ion implantation techniques have been used to improve the surface hardness and tribological properties of AISI 420 substrates. Firstly polished-AISI 420 samples are nitrided at 530 °C for 15 h at a pressure of 10 mbar. Then nitrided samples are implanted with nitrogen ions to a dose of 2 × 1017 ions/cm2. Mechanical characterization of both of the modified and unmodified samples has been carried out by means of nano-hardness, wear resistance, friction coefficient and surface roughness measurements. It is found that the nano-hardness, wear resistance, friction coefficient and surface roughness values improve 1.6, 3.5, 1.4 and 10 times for plasma nitrided samples, and 2.0, 4.6, 1.1 and 9 times for plasma nitrided-plus-N+ ion implanted samples, respectively, in comparison with unmodified AISI 420 samples. Both the plasma nitriding process and the plasma nitriding-plus-N+ ion implantation treatment sample results are also compared. The improvement of the samples modified using nitriding-plus-N+ ion implantation process is found to be better than that of samples modified by the nitriding process. © 2007 Elsevier B.V. All rights reserved.Item Characterization of Ti + N and Zr ion implanted 316 L stainless steel(2007) Tek Z.; Öztarhan A.; Selvi S.In this study, polished 316LSS stainless steel has been implanted with Ti + N and Zr ions at fluence of 2 × 1017 ions/cm2 and 1 × 1017 ions/cm2, respectively. Ion charge state distributions of Ti + N and Zr were measured by time-of-flight spectrometry, and the mean energies of these ions were determined. The Zr concentration profiles were obtained by Rutherford backscattering spectrometry. The range distribution of ions in implanted and unimplanted samples were evaluated using TRIM and STOPPO programs and the results were compared with the experimental data, which were in good agreement. The influence of the ions on the mechanical behavior of the 316LSS was investigated. The measurements show that after Ti + N implantation; the friction coefficient decreases, the hardness value increases, the wear resistance decreases and after Zr implantation; the friction coefficient decreases, the hardness value increases and the wear resistance increases with respect to an unimplanted sample. © 2007 Elsevier B.V. All rights reserved.Item Thermal characterization of Ag and Ag + N ion implanted ultra-high molecular weight polyethylene (UHMWPE)(2007) Sokullu Urkac E.; Oztarhan A.; Tihminlioglu F.; Kaya N.; Ila D.; Muntele C.; Budak S.; Oks E.; Nikolaev A.; Ezdesir A.; Tek Z.Most of total hip joints are composed of ultra-high molecular weight polyethylene (UHMWPE ). However, as ultra-high molecular weight polyethylene is too stable in a body, wear debris may accumulate and cause biological response such as bone absorption and loosening of prosthesis. In this study, ultra-high molecular weight polyethylene samples were Ag and Ag + N hybrid ion implanted by using MEVVA ion implantation technique to improve its surface properties. Samples were implanted with a fluence of 1017 ion/cm2 and extraction voltage of 30 kV. Implanted and unimplanted samples were investigated by thermo-gravimetry analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), optical microscopy (OM) and contact Angle measurement. Thermal characterization results showed that the ion bombardment induced an increase in the % crystallinity, onset and termination degradation temperatures of UHMWPE. © 2007 Elsevier B.V. All rights reserved.Item Ion implantation inhibits cell attachment to glassy polymeric carbon(2007) Zimmerman R.; Deliloglu-Gurhan I.; Ozdal-Kurt F.; Sen B.H.; Rodrigues M.; Ila D.Implantation of MeV gold, oxygen, carbon ions into GPC alters the surface topography of GPC and enhances the already strong tendency for cells to attach to GPC. We have shown that implantation of silver ions near the surface strongly inhibits cell growth on GPC. Both enhanced adhesion of and inhibition of cell growth are desirable improvements on cardiac implants that have long been successfully fabricated from biocompatible glassy polymeric carbon (GPC). In vitro biocompatibility tests have been carried out with model cell lines to demonstrate that ion beam assisted deposition (IBAD) of silver, as well as silver ion bombardment, can favorably influence the surface of GPC for biomedical applications. © 2007 Elsevier B.V. All rights reserved.Item Optical properties of Tb implantation into ZnO(2007) Çetin A.; Kibar R.; Ayvacikli M.; Tuncer Y.; Buchal Ch.; Townsend P.D.; Karali T.; Selvi S.; Can N.ZnO [0001] single crystals were implanted at room temperature with 400 keV Tb+ ions at fluences in the range of 1 × 1016-2 × 1017 ions/cm2. Zinc oxide was chosen because of its potential for photonic applications as a semiconductor with high radiation resistance. After implantation and post-irradiation annealing, optical absorption was measured in a UV-VIS-NIR range and radioluminescence spectra were recorded at room temperature. Emission signals were generated by the Tb+ ion implants and intrinsic emission of the ZnO matrix were observed. The implant signal intensities were comparable with the host radioluminescence, even though the implants modify the surface of the crystal. It is suggested that the presence of Tb at high concentration generates stresses which influence the bulk material and also potentially forms precipitates or nanoparticles in the near surface region. Overall ion implantation of ZnO results in strongly modified luminescence. © 2007.Item Enhanced biocompatibility of GPC by ion implantation and deposition(2007) Zimmerman R.; Gürhan I.; Muntele C.; Ila D.; Rodrigues M.; Özdal-Kurt F.; Sen B.H.Biocompatible Glassy Polymeric Carbon (GPC) is used for artificial heart valves and in other biomedical applications. Although it is ideally suited for implants in the blood stream, tissue that normally forms around the moving parts of a GPC heart valve sometimes loses adhesion and creates embolisms downstream. We have previously shown that oxygen ion implantation slightly enhances cell adhesion to GPC. Here we compare silver ion implantation and silver deposition, each of which strongly inhibits cell attachment on GPC. Inhibition of cell adhesion is the more desirable improvement to current GPC cardiac implants. In vitro biocompatibility tests have been carried out with model cell lines to demonstrate that traces of silver can favorably influence the surface of GPC for biomedical applications. © 2007.Item Modification of surface morphology of UHMWPE for biomedical implants(Materials Research Society, 2007) Oztarhan A.; Urkac E.S.; Kaya N.; Yenigul M.; Tihminlioglu F.; Ezdesir A.; Zimmerman R.; Budak S.; Muntele C.; Chhay B.; Ila D.; Oks E.; Nikolaev A.; Tek Z.; Eltem R.Ultra High Molecular Weight Polyethylene (UHMWPE) samples were implanted with metal and metal-gas hybrid ions (Ag, Ag+N, C+H, C+H+Ar, Ti+O) by using improved MEVVA Ion implantation technique [1,2]. An extraction voltage of 30 kV and influence of 1017 ions/cm2 were attempted in this experiment, to change their surface morphologies in order to understand the effect of ion implantation on the surface properties of UHMWPEs. Characterizations of the implanted samples with RBS , ATR - FTIR, spectra were compared with the un-implanted ones . Implanted and unimplanted samples were also thermally characterized by TGA and DSC. It was generally observed that C-H bond concentration seemed to be decreasing with ion implantation and the results indicated that the chain structure of UHMWPE were changed and crosslink density and polymer crystallinity were increased compared to unimplanted ones resulting in increased hardness. It was also observed that nano size cracks (approx.10nm) were significantly disappeared after Ag implantation, which also has an improved antibacterial effect. Contact angle measurements showed that wettability of samples increased with ion implantation. Results showed that metal and metal+gas hybrid ion implantation could be an effective way to improve the surface properties of UHMWPE to be used in hip and knee prosthesis. © 2007 Materials Research Society.Item Polymeric thermal analysis of C + H and C + H + Ar ion implanted UHMWPE samples(2007) Kaya N.; Oztarhan A.M.; Urkac E.S.; Ila D.; Budak S.; Oks E.; Nikolaev A.; Ezdesir A.; Tihminlioglu F.; Tek Z.; Cetiner S.; Muntele C.Chemical surface characterization of C + H hybrid ion implanted UHMWPE samples were carried out using DSC (differential scanning calorimeter) and TGA (thermal gravimetric analysis) techniques. Samples were implanted with a fluence of 1017 ion/cm2 and an extraction voltage of 30 kV. The study of TGA and DSC curves showed that: (1) Polymeric decomposition temperature increased, (2) Tm, ΔCp and ΔHm values changed while ΔCp and ΔHm increased. Tg value could not be measured, because of some experimental limitations. However, the increase in ΔHm values showed that Tg values increased, (3) the branch density which indicated the increase in number of cross-link (Mc) decreased in ion implanted samples and (4) increase in ΔHm values indicated increase in crystallinity of implanted surface of UHMWPE samples.