Silver Ion Implantation Research Articles

Powder synthesis, sintering, and characterization of Ba 1+xZr 6−2xSi 2xO 24 -A low thermal expansion system

HCF tests on polycrystalline alpha-iron with and without silver, chromium, yttrium, and aluminum ion implantation have been conducted. The stress-life curves obtained were best fit by using the power function. It was shown that the fatigue property had been improved to different extent after ion implantation. Enhanced strengthening of the implanted layer due to radiation induced defects, super solid solution, and formation of intermetallic compounds in implantation was the prominent mechanism for property improvement.

High-temperature ion implantation into quartz

Ion implantation of copper, gallium and silver ions into quartz substrates has been performed. The implantation parameters were identical for each series of implants: 55 keV ion energy and an implanted dose of 6.4*1016 ions cm-2. However, the temperature of the substrate was varied with implants being done at room temperature, 373 K, 498 K, 623 K and 873 K. Rutherford backscattering was used to provide depth profiles for the implanted ions and the substrate elements; the ion profiles were compared with simulations from the TRIM code. The ion profiles were significantly affected by temperatures in all three cases: in particular, bimodal distributions formed at 498 K for the copper and gallium implants and at 623 K for the silver. The ions amorphized the substrate to depths commensurate with the tail of the implant except in the 873 K silver implant. In this case none of the silver was retained and the substrate completely recrystallized. Evidence of recrystallization was also evident in the gallium 873 K implants, which had a smaller amorphization depth than the lower temperature implants.

High temperature silver ion implantation into glass

Soda-lime-silicate glass has been implanted with 55 keV Ag + ions at five different temperatures: room temperature, 100, 225, 350 and 600°C. Rutherford backscattering spectroscopy was used to provide depth profiles for the implants. All samples show a low retention of silver and this varies with temperature. In the room temperature and 100°C implants the silver diffuses to, and is lost from the surface. This also occurs in the higher temperature implants, but in these cases there is a significant amount of inward diffusion by the silver. This diffusion extends to at least 500 nm: greatly in excess of the predicted range for a standard implant. Optical measurements on the samples show that those with the inward diffusion have formed an enhanced-index waveguide.

Colloid size distributions in ion implanted glass

Ion implantation of silver ions at 60 keV into silicate glass produces metallic colloids. Colloid growth during implantation as recorded by in situ changes in optical reflectivity. Post implant analyses indluded optical absorption, Rutherford backscattering and transmission electron microscopy. The optical data imply there is a range of colloid sizes and the details of colloid size as a function of depth are determined by the TEM measurements of thinned samples. The factors influencing the changes in the optical data with ion dose and the depth dependence of the colloid size distribution are discussed.

Implantation of titanium, chromium, yttrium, molybdenum, silver, hafnium, tantalum, tungsten and platinum ions generated by a metal vapor vacuum ion source into 440C stainless steel

Titanium, yttrium, molybdenum, silver, chromium, hafnium, tantalum, tungsten and platinum ions generated by a metal vapor vacuum arc (MEVVA) ion source were implanted into 440C stainless steel in the dose region 10 17 ions cm -2 with extraction voltages of up to 70 kV. Glow discharge spectroscopy (GDS), friction coefficient, and Vickers microhardness of the specimens were studied. Grooves made by friction tests were investigated by electron probe microanalysis (EPMA). GDS showed incorporation of carbon in the yttrium, hafnium, tantalum, tungsten and platinum implanted specimens, as well as titanium implanted samples. A large amount of oxygen was observed in the yttrium implanted specimen. The friction coefficient was measured by reciprocating sliding of an unimplanted 440C ball without lubricant at a load of 0.245 N. The friction decreased and achieved a stable state after implantation of titanium, hafnium and tantalum. The friction coefficient of the platinum implanted specimen showed a gradual decrease after several cycles of sliding at high friction coefficient. The yttrium implanted sample exhibited a decreased but slightly unstable friction coefficient. Results from EPMA showed that the implanted elements, which gave decreased friction, remained even after sliding of 200 cycles. Implantation of chromium, molybdenum, silver and tungsten did not provide a decrease in friction and the implants were gone from the wear grooves after the sliding tests.

RAMAN SCATTERING STUDY OF Ag+-IMPLANTED β-ALUMINA CRYSTALS

We have measured Raman spectra of sample of sodium β-alumina and samples with silver ion implantation where one kind of sample was not annealed after the implantation, and the others were Ag +-implanted with annealing for 30 minutes at 300, 400, 500 and 700°C, respectively. Raman spectra show that silver ion implantation disturbs sublattice of Na + in β-alumina with some disorder features and some resonance modes appeared in the Raman spectra. We have found the critical annealing temperature near 400°C, above which the silver ion, typically with small activation energy 0.18 eV, gains enough energy to diffuse rapidly through the vacancy clusters formed by silver ion implantation and also through the conduction plane of crystal between clusters in β-alumina with high ionic conductivity.

Influence of the implantation of transition metal ions on the electrocatalytic activity of carbon materials

The influence of implantation of titanium, vanadium, chromium iron, cobalt, nickel, zirconium, molybdenum, silver, tungsten, iridium and platinum ions on the catalytic activity of polycrystalline graphite and glassy carbon for the electrochemical hydrogen evolution reaction has been studied. The factors causing an increase of material activity as a result of ion beam modification were determined. Implanted layers were investigated by XPS and voltammetric measurements. The formation of metastable states of implanted transition metal atoms in the carbon matrix has been established. These states are characterized by an unexpected high extent of unoccupancy of d-electronic valence levels. The transition of the implanted system in the equilibrium state occurs by metal atom diffusion and precipitation. Active sites of electronic exchange in the near-surface substrate region are bound to implanted metal atoms or their precipitates. These phenomena result in an increase of adsorptivity and considerable decrease of hydrogen overpotential on modified electrodes.

Improving the wear resistance of metal forming tools by ion implantation

A facility for wear tests under simulated production conditions was installed. These tests permit variations in essential parameters of the forming processes “backward can extrusion” and “upsetting between flat parallel dies”, which were investigated in this work. For measuring sufficient wear, 10 000 to 20 000 workpieces had to be pressed. To reduce the time, in some cases a short-time testing procedure based on a radionuclide technique was used. In this, thin surface layer of the tool was activated by deuteron irradiation. During the wear process the activity of the tool decreased because of loss of material. This enabled the determination of wear after only 2000–3000 manufactured workpieces. By applying nitrogen-ion-implanted tools, wear decreased down to the level of conventionally nitrided tools. The great advantage of the former process is the low temperature of treatment; so the roughness and structure of the material are not affected and tools can be machined to their final dimensions before ion implantation. The results of nitrogen implantation are compared with those of nitrogen plus silver ion implantation and nitrogen plus tin ion implantation. A comparison of the two forming processes, different tool materials and various surface treatments should contribute to economic application of optimized wear-resistant tools in bulk metal forming processes.

Erosion and Transfer in Electrical Contacts Measured Using the Thin Layer Activation Technique

The application of an ion beam activation technique to erosion studies in electrical contacts is demonstrated. The technique, which is based upon the labeling of a thin layer of surface atoms by high energy ion beam activation, is sensitive to both material loss from the activated layer and transfer to other components. As only a thin layer is activated the induced activity levels are low and the samples require only elementary radiological handling precautions. The information that can be obtained with the technique is demonstrated with the use of a readily available automobile contact rig incorporating tungsten contacts. Preliminary estimates of the erosion conditions are made, and the technique is then tailored to optimize experimental measurements. A typical measurement of material transfer between the two electrode faces was 50 ± 3 µg per 2 h of operation. An attempt to modify the properties of electrodes and hence their erosion rates by the ion implantation of silver ions is also reported.

Some electrical and photoelectric properties of inhomogeneous structures obtained by implantation of silver ions in cadmium selenide single crystals

The inhomogeneous structures investigated in the present work were obtained by implantation of silver ions in low-resistivity (p ~ 0.i-i.0 ~.cm and Wn 2 600 cm2/V.sec at 300~ cadmium selenide crystals which had been subjected to chemical and mechanical polishing followed by etching. The silver ions were implanted at room temperature with energy 350 keV and in doses of 2.10 z~, 7"10 I~, and 2"10 ~5 ions/cm 2. After implantation of the silver the specimens were annealed in a stream of inert gas (Ar) under an Si02 masking layer i000 thick in the temperature range 300-500~ for 20 min. Before the measurements the Si02 layer was removed and gold and indium contacts were deposited on the doped and undoped sides, respectively, of the specimens.