Improving the Adhesion of Multi-Walled Carbon Nanotubes to Titanium by Irradiating the Interface with He+ Ions: Atomic Force Microscopy and X-ray Photoelectron Spectroscopy Study.

A complex study of the adhesion of multi-walled carbon nanotubes to a titanium surface, depending on the modes of irradiation with He+ ions of the "MWCNT/Ti" system, was conducted using atomic force microscopy and X-ray photoelectron spectroscopy. A quantitative assessment of the adhesion force at the interface, performed using atomic force microscopy, demonstrated its significant increase as a result of treatment of the "MWCNT/Ti" system with a beam of helium ions. The nature of the chemical bonding between multi-walled carbon nanotubes and the surface of the titanium substrate, which causes this increase in the adhesion of nanotubes to titanium as a result of ion irradiation, was investigated by X-ray photoelectron spectroscopy. It was established that this bonding is the result of the formation of chemical C-O-Ti bonds between titanium and carbon atoms with the participation of oxygen atoms of oxygen-containing functional groups, which are localized on defects in the nanotube walls formed during ion irradiation. It is significant that there are no signs of direct bonding between titanium and carbon atoms.

Comparative Study of the Structural Features and Electrochemical Properties of Nitrogen-Containing Multi-Walled Carbon Nanotubes after Ion-Beam Irradiation and Hydrochloric Acid Treatment.

Using a set of microscopic, spectroscopic, and electrochemical methods, a detailed study of the interrelation between the structural and electrochemical properties of the as-prepared nitrogen-containing multi-walled carbon nanotubes (N-MWCNTs) and their modified derivatives is carried out. It was found that after treatment of nanotubes with hydrochloric acid, their structure is improved by removing amorphous carbon from the outer layers of N-MWCNTs. On the contrary, ion bombardment leads to the formation of vacancy-type structural defects both on the surface and in the bulk of N-MWCNTs. It is shown that the treated nanotubes have an increased specific capacitance (up to 27 F·g-1) compared to the as-prepared nanotubes (13 F·g-1). This is due to an increase in the redox capacitance. It is associated with the reversible Faraday reactions with the participation of electrochemically active pyridinic and pyrrolic nitrogen inclusions and oxygen-containing functional groups (OCFG). Based on the comparison between cyclic voltammograms of N-MWCNTs treated in HCl and with an ion beam, the peaks on these curves were separated and assigned to specific nitrogen inclusions and OCFGs. It is shown that the rate of redox reactions with the participation of OCFGs is significantly higher than that of reactions with nitrogen inclusions in the pyridinic and pyrrolic forms. Moreover, it was established that treatment of N-MWCNTs in HCl is accompanied by a significant increase in the activity of nitrogen centers, which, in turn, leads to an increase in the rate of redox reactions involving OCFGs. Due to the significant contribution of redox capacitance, the obtained results can be used to develop supercapacitors with increased total specific capacitance.

Data on the morphology and chemical state of coatings based on TiN obtained by condensation with ion bombardment on various substrates.

This article presents the effect of the substrate on the morphology and chemical composition of titanium nitride coatings formed using the condensation with ion bombardment method. Various steels, sintered hard alloy (tungsten carbide - 92%, cobalt - 8%) and titanium-based alloy were used as substrates. The paper presents the XPS data obtained at various depths from the surface. The article also presents the data of the wear resistance of coatings for road milling cutters.

Data on the structure, chemical state of carbon and discharge characteristics of multi-walled carbon nanotubes and composites based on them modified by pulsed ion beam.

The data presented in this article are related to the research article entitled "Structure and electrochemical characterization of SnOx/Sn@MWCNT composites formed by pulsed ion beam irradiation" (Korusenko et al., 2019). This article presents the effect of irradiation by pulsed ion beam (PIB) irradiation at various modes on the structure multi-walled carbon nanotubes (MWCNTs) and composites based on MWCNTs and tin oxide as well as cycling performance of these composites. The article also presents the results of the analysis of the structure of the electrodes, obtained on the basis of the initial and irradiated composites.