Modification of stainless steel based on synergistic of low-energy high-intensity ion implantation and high-current electron beam impact on the surface layer

The results of experiments on low-energy implantation of AISI 321 stainless steel by nitrogen ions are presented. The treatment was carried out by a pulsed beam of nitrogen ions obtained using a ballistic ion focusing system. The surface modification occurs with the formation of a two-layer structure, which is typical for ion-plasma nitriding processes of stainless steels. The thickness of the modified layer can reach 27 μm after 1 hour of ion-plasma treatment. The influence of subsequent modification of the ion-doped layer by the action on the surface of the pulsed high-current electron beam of microsecond duration is studied. The work presents the results of the studying the regularities of changes in the depth distribution of dopants, microstructure and phase composition of the modified and matrix layers by optical metallography, diffraction analysis and transmission electron microscopy.

Effect of Nitrogen Ion Implantation Energy on the Mechanical and Chemical Properties of AISI M50 Steel

Nitrogen ion implantation has shown its role in enhancing steel surface properties. In this work, AISI M50 steel was implanted with nitrogen ions by using the metal vapor vacuum arc technique with a dose of 2 × 1017 cm−2, and corresponding implanted energies were at 60 keV, 80 keV, and 100 keV, respectively. The distribution of implanted nitrogen ions was calculated, and the samples were tribologically tested and examined. As shown by the results, the microhardness in implanted samples was 1.17 times greater relative to that of the unimplanted sample. The implantation of the nitrogen ion leads to a change in the friction coefficient of the AISI M50 steel. Adhesive wear mechanism occurs in the unimplanted sample, and adhesion resistance tends to increase when nitrogen-implanted energy increases. The formation of oxides α-Fe2O3 and Fe3O4 further enhanced the tribological properties for implanted samples.

Study of Concentration-depth Profiles of the Titanium and Nitrogen Ions by SRIM/TRIM Simulation

In this research, the concentration-depth profiles reached by titanium and nitrogen particles, on the surface of AISI/SAE 1020 carbon steel substrates, by using of ion implantation technique, are studied. The ions are surface deposited by means of high voltage pulsed discharges and electric arc discharge under high vacuum conditions. The concentration and position distribution of the metallic and non-metallic species are obtained by simulation of the interaction of ions with the matter, stopping and ranges of ions in the matter, by the computer program transport of ions in matter. The implantation dose is calculated from the discharge data and the previously established study parameters in this work. From the simulation results, the depth profiles demonstrated that titanium and nitrogen ions may reach up to 300 Å and 600 Å and concentrations of 1.478 x 1016 ions⁄cm2 and 2.127 x 1016 ions⁄cm2, respectively. The formation of titanium microdroplets upon the surface of the substrates is identified from the micrographs obtained by the scanning electron microscopy technique; furthermore, the presence of titanium and nitrogen implanted on the surface of the substrate is verified through the elemental composition analysis by the energy dispersive spectroscopy, validating the effect of ion implantation on ferrous alloys.

Fabrication and Surface Deformation of Boron Nitride Nanotubes by RF Plasma and Ion Beam

Boron Nitride Nanotubes (BNNT) are one of the candidate materials for storing hydrogen by physical adsorption. It has been reported that this hydrogen storage capacity increases as the crystallinity of the nanostructures decreases. Here, BNNT was synthesized using an RF plasma torch system, and the surface of the BNNT was irradiated with nitrogen ions using an ion beam device, and changes in the surface microstructure were subsequently investigated. A multi-walled BNNT with a wall thickness of about 5 nm was synthesized using a 60 kW RF plasma torch. Amorphous impurities generated during the synthesis process were removed by heat treatment and membrane filtering. Then nitrogen ions were irradiated for 40 minutes at energies of 40 keV and 50 keV, respectively, using an ion beam irradiation device. The changes in the microstructure of the BNNT surface following ion beam irradiation were confirmed by HR-TEM, Raman spectrometer and FT-IR spectrometer. The tube walls of the BNNT were disordered by the nitrogen ions irradiation. At 50 keV, the tube walls located in the middle became disordered, which was attributed to an increase in penetration depth due to the higher irradiation energy. The maximum peak in the Raman spectra and FT-IR spectra of the ion irradiated BNNT were also shifted to a lower frequency. Ion irradiation reduced the crystallinity of the nanostructures. The potential improvement in hydrogen storage capacity by nitrogen ion irradiation of BNNT was confirmed.