Hybrid gas-metal co-implantation with a modified vacuum arc ion source

Energetic beams of mixed metal and gaseous ion species can be generated with a vacuum arc ion source by adding gas to the arc discharge region. This could be an important tool for ion implantation research by providing a method for forming buried layers of mixed composition such as e.g. metal oxides and nitrides. In work to date, we have formed a number of mixed metal-gas ion beams including Ti+N, Pt+N, Al+O, and Zr+O. The particle current fractions of the metal-gas ion components in the beam ranged from 100% metallic to about 80% gaseous, depending on operational parameters. We have used this new variant of the vacuum arc ion source to carry out some exploratory studies of the effect of Al+O and Zr+O co-implantation on tribology of stainless steel. Here we describe the ion source modifications, species and charge state of the hybrid beams produced, and results of preliminary studies of surface modification of stainless steel by co-implantation of mixed Al/O or Zr/O ion beams. 5 figs, 21 refs

SURFACE & COATINGS TECHNOLOGY

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 similar to 50 pulses per second and the extracted ion beam current can be up to -1 A peak or similar to 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. (c) 2004 Elsevier B.V. All rights reserved

ION-BEAM-BASED NANOFABRICATION

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

Erratum to "Wear behavior of nitrogen implanted PVD-coated hard metal cutting inserts" [Surface and Coatings Technology 176 (2005) 369-372] (DOI:10.1016/j.surfcoat.2004.08.205)

[No abstract available

Properties of Metal and Metal-Gas Hybrid Ion Implanted Chrome-tanned Leather Surfaces

Leather samples were modified by Ag and Zn+O ion implantation using a metal vapour vacuum arc (MEVVA) implanter. The ions were implanted at an accelerating voltage of 30kV and with 1 x 10(14), 1 x 10(15) and 1 x 10(16) ions/cm(2) fluences, and results were compared with an unimplanted control group. The surface morphologies of the samples were examined by scanning electron microscopy. The physical properties (tensile strength and tear load), CIE lab colour analysis, contact angle measurements and FTIR were also examined. The results showed that this technique can fulfill expectations of better quality and, environmentally friendly and waterproof leather processing

Nano- and micro-structural evolution of UHMWPE by ion beam

Symposium on Ion-Beam-Based Nanofabrication held at the 2007 MRS Spring Meeting -- APR 10-12, 2007 -- San Francisco, CAWOS: 000250475100022It is important to produce uniform nano-patterns with no possibility of surface exfoliation on polyethylene devices used in medical and in aerospace industry. We studied the change in the surface morphology of polyethylene at nanoscale using MeV ion beam. We have investigated the change in the surface morphology before and after ion bombardment. We have made an attempt to change the morphology to produce a uniform surface with reduced cracks and reduced granularity. For this process we have chosen ultra-high-molecular-weight polyethylene (UHMWPE). Coupons of these materials were exposed to various fluences of MeV Ag+ ions. The surface morphology and the change in the chemical structure were studied using scanning micro Raman, FTIR and AFM.Center for Irradiation of Materials, Alabama AM University; NSF-EPSCoR [EPS-0447675]This research was sponsored by by the Center for Irradiation of Materials, Alabama A&M University and supported by NSF-EPSCoR grant No. EPS-0447675

Comparison of the mechanical properties of nitrogen ion implantation and micro-pulsed plasma nitriding techniques of Cr-Ni alloy

12th International Conference on Surface Modification of Materials by Ion Beams -- SEP 09-14, 2001 -- MARBURG, GERMANYWOS: 000178482100029Cr-Ni alloys are frequently used in dentistry for economical reasons. While they gain popularity, an increase in systemic and local concerns of these dental metals is observed. With the progressions in surface technology, the surface characteristics of the metals can be changed. In this study, nitrogen ion (N ion) implantation and plasma nitriding techniques were used to change the properties of Cr-Ni alloy (Wirollay). Nitrogen implantation at dose 1 X 10(17) ion/cm(2) and micro-pulsed plasma nitriding techniques were applied to Cr-Ni alloy samples. After the process, the friction coefficient was decreased in ion implantation, but this ratio was increased in the plasma nitriding technique with respect to the substrate. The roughness did not change after N ion implantation but it increased after the plasma nitriding procedure. Wear volume of the implanted and plasma nitriding samples were lower than the substrate. Hardness values were increased four times for N ion implantation and eight times for the plasma nitriding technique. (C) 2002 Elsevier Science B.V. All rights reserved.Philipps Univ Marburg, Gesell Schwerionenforsch mb