GXRD analysis of TiN coatings deposited on ion implanted stainless steel

Nitrogen ion implantations were performed on AISI 1045 steel substrates. The ion energy was 40 keV and the ion doses were from 5x1016 – 5x1017 ions cm-2. On such substrates we have deposited 1.3 μm thick TiN coatings. Structural characterizations were performed by grazing incidence X-ray diffraction analysis (GXRD), normal X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM). Microhardness was measured by Vicker`s method. The obtained results indicate that the formation of iron nitrides occurred in the near surface region of the substrates. This effect is more pronounced for higher implantation doses. Structure of the deposited TiN coatings shows a dependence on the implanted doses. Ion implantation and deposition of hard TiN coatings induce an increase of microhardness of this low performance steel for more than eight times.YUCOMAT 2006 : 8th Annual Conference YUCOMAT 2006 : Septembar 4-8, Herceg Novi, 2006

Fuzzy methaheuristic model for copy-move forgery detection on images

Many methods have been proposed to detect the originality of an image. One of the most commonly used method, the Copy - move forgery detection (CMFD), is considered here. The contribution of this paper is the application of the new fuzzy distances in clustering using metaheuristics. The family of the used fuzzy distances satisfies the axioms of the fuzzy metric. CMFD method, which includes Variable Neighborhood Search (VNS) and Bee Colony Optimization (BCO) metaheuristics, has been tested and compared with similar methods. The proposed method with the proposed new metric used in this research gave better results than the existing methods. The proposed fuzzy metrics in this paper as well as the problem of $$p-$$median clustering applied to the problem and compared with existing research in this field give better results

Atomic mixing and interface reactions in Ta/Si bilayers during noble-gas ion irradiation

This article focuses on the influence of chemical driving forces on the mixing and phase formation taking place at the interface of highly reactive metal/semiconductor systems under ion-beam irradiation. Ta/Si bilayers were irradiated with Ar, Kr, and Xe ions to fluences of (0.5-2.5) X 10(16) ions/cm(2) and at temperatures between liquid nitrogen and 400degreesC. The interface mixing and silicide formation were monitored as function of the ion mass and fluence by means of Rutherford backscattering spectrometry and x-ray diffraction. The interface broadening variance was found to depend linearly on the ion fluence and was explained with the help of a compound formation model involving local or global thermal spikes. The results are compared with those found in other silicide and germanide systems. The transition from local to global spikes was found to occur at the critical deposited damage energy of about 2.5 keV/nm

Mixing and silicide formation during Xe-ion beam irradiations of Ta/Si bilayers

Thin Ta layers deposited on Si (100) substrates were irradiated with 475 keV Xe+ ions to fluences of (0.5-2) x 10(16) ions/cm(2) at temperatures between room temperature and 400 degreesC. By means of Rutherford Backscattering Spectrometry, the interface mixing and tantalum silicide formation were monitored as function of the ion fluence. TaSi2 phase formation was verified using X-ray diffraction. The interface broadening variance was found to depend linearly on the ion fluence and was explained with the help of a compound formation model involving global thermal spikes

The L3A facility at the Vinca Institute: Surface modification of materials, by heavy ion beams from an electron cyclotron resonance ion source

This article describes the L3A experimental facility for surface modification of materials at the Vinca Institute of Nuclear Sciences, in Belgrade. This facility was completed and put into operation in May 1998. It is connected to the mVINIS ion source, an electron cyclotron resonance ion source capable of producing a wide range of multiply charged ions from gaseous and solid substances. The heavy ion beams obtained from mVINIS are separated by charge to mass ratio (q/m) and transported to the target chamber for sample irradiation and modification. The target chamber is equipped with a multipurpose target holder, an electron-beam evaporation source for thin layer deposition, a residual gas analyzer, and other auxiliary equipment. There is also an additional low energy argon ion source for target preparation/sputtering and for ion beam assisted deposition. In this article we describe the layout and performances of the L3A facility, the experience gained during 1 yr of operation, and the requirements imposed by the current and future experimental programs. Currently, there are 24 experimental programs competing for the ion beam time at the L3A facility. (C) 2000 American Institute of Physics. [S0034-6748(00)59102-3]

Interface mixing in Ta/Si bilayers with Ar ions

We report on the room-temperature synthesis of the low-resistivity TaSi2 phase using ion-beam mixing of Ta/Si bilayers with Ar ions. The formation of the silicide phase is observed for different damage energies deposited at the Tal Si interface. The variance Delta sigma(2) of the reacted (TaSi2) layer thickness varies linearly with the ion fluence Phi and the reaction rate Delta sigma(2)/Phi, is proportional to the deposited damage energy density F-D. The measured mixing/reaction efficiency, Delta sigma(2)/Phi F-D = 10 +/- 1 nm(5)/keV, is in agreement with the value calculated by the model of compound formation under local thermal spikes. (C) 2000 Elsevier Science B.V. All rights reserved.14th International Conference on Ion Beam Analysis/6th European Conference on Accelerators in Applied Research and Technology, Jul 26-30, 1999, Dresden, German

Ion-beam mixing in Fe/Si bilayers by singly and highly charged ions: evolution of phases, spike mechanism and possible effects of the ion-charge

Silicide formation and ion beam mixing of Fe/Si bilayers due to Ar-, Xe- and Au-ion irradiations at room and liquid-nitrogen temperatures were investigated. For the study of silicide phase formation, the Fe/Si bilayers were irradiated with 100-keV Ar+, 250-keV Xe+, 700-keV Xe2+ or 400-keV Au+ ions at fluences of 1 x 10(15) to 2 x 10(16) ions/cm(2). The influence of the ion-charge state on the mixing process was studied in Fe/Si by 100-keV Ar8+-ion implantation, in addition to the corresponding irradiations with singly charged ions at the same energy. Changes in the samples were analyzed by Rutherford backscattering spectroscopy, conversion electron Mossbauer spectroscopy, X-ray diffraction and atomic force microscopy. Pronounced structural changes and the intermixing of the components at the Fe/Si interfaces were measured as a function of the ion species, ion fluence and, sample temperature. A linear correlation between the interface broadening and the fluence was observed for all the cases. Mossbauer analysis with enriched Fe-57 layers revealed the onset of phase formation out of the solid solution. In order to interpret the mixing rates in this most general case, we considered mixing through thermal local or global spikes and compound formation. The highly charged Ar8+-ion irradiation produced a higher athermal mixing rate compared to singly charged Ar+ ions, and this result could not be explained by the above models

Direct synthesis of beta-FeSi2 by ion beam mixing of Fe/Si bilayers

The iron di-silicide beta-FeSi2 is a promising direct band gap semiconductor but difficult to produce. Here, the successful direct synthesis of this phase by ion beam mixing of Fe/Si bilayers at temperatures in the range of 450 to 550 degrees C is reported. The obtained single-phase beta-FeSi2 layers and their structure are confirmed by Rutherford backscattering spectrometry, X-ray diffraction and conversion electron Mossbauer spectroscopy. PACS: 61.80.Jh; 68.55.Nq; 61.82.Fk

New facile one-pot synthesis of S-alkyl thiolcarbamates from xanthogenate in water

A simple and efficient one-pot synthesis was developed for the preparation of S-alkyl thiolcarbamates from xanthogenate without catalyst using water as a solvent. The water can be recycled after removal of the product. The significant features of this protocol are: operational simplicity, mild reaction conditions, recycling of solvent and high product yields. Starting basic alkyl xanthogenate reacts with alkyl ammonium sulfate (aryl ammonium sulfate) and hydrogen peroxide (molar ratio 1:0.55:1) in water at 40 A degrees C for 1 h, followed by additional heating at 70-110 A degrees C for 1-2.3 h. Good to excellent yields were achieved using ammonium sulfate in 10 % molar excess

Growth of beta-FeSi2 films via noble-gas ion-beam mixing of Fe/Si bilayers

A detailed study of the formation of beta -FeSi2 films by ion-beam mixing of Fe/Si bilayers with noble gas ions is presented. Fe films of 35-50 nm deposited on Si (100) were irradiated with 80-700 keV Ar, Kr, or Xe ions in a wide temperature interval, from room temperature to 600 degreesC. The structures were analyzed by Rutherford backscattering spectroscopy, x-ray diffraction, conversion electron Mossbauer spectroscopy, elastic recoil detection analysis, cross-section high resolution transmission electron microscopy, and energy dispersive x-ray spectroscopy. Already after Xe irradiation at 300 degreesC the whole Fe layer is transformed to a mixture of Fe3Si, epsilon -FeSi, and beta -FeSi2 phases. At 400-450 degreesC, a unique, layer by layer growth of beta -FeSi2 starting from the surface was found. A full transformation of 35 nm Fe on Si to a 105 nm beta -FeSi2 layer was achieved by irradiation with 205 keV Xe to 2x10(16) ions/cm(2), at a temperature of 600 degreesC. The fully ion-beam grown layers exhibit a pronounced surface roughness, but a sharp interface to Si. This structure is assigned to a growth of beta -FeSi2 grains in a local surrounding of interdiffused silicon. Rapid diffusion of silicon to the surface was observed during all ion irradiations. Single-phase beta -FeSi2 layers were also synthesized by vacuum annealing for 2 h at 600 degreesC of 35 nm Fe/Si bilayers premixed with Xe at 450 degreesC. In this case, the layers form with a smoother surface topography. It is concluded that ion-beam mixing can be used successfully for growth of beta -FeSi2 layers at moderate temperatures, either directly or combined with postirradiation annealing. (C) 2001 American Institute of Physics