F. Z. Gil’mutdinov

Effect of the burning temperature on the phase composition, photovoltaic response, and electrical properties of Ag/Pd resistive films

Silver-palladium (Ag/Pd) films were grown by thick-film technology using a resistive paste consisting of Pd, Ag2O, and glass on ceramic substrates at burning temperatures of 878, 1013, and 1113 K. The effect of the burning temperature and Pd content in the initial paste on the phase composition, resistivity, photovoltaic properties of films, free carrier concentration, and mobility was studied. It was found that the films grown at a burning temperature of 878 K have the greatest factor of conversion of the pulsed laser power to the photovoltaic signal, which depends on the direction of the incident radiation wave vector. Using X-ray diffraction, X-ray photoelectron spectroscopy, and thermodynamic modeling, it was shown that the AgPd alloy and PdO oxide are the main components of the Ag/Pd film with photovoltaic properties.

Corrosion-electrochemical behavior of nanostructured chromium oxide layers obtained by laser irradiation of unalloyed steel by short pulses

Laser short-pulse treatment of ultradispersed powdered chromium(III) oxide supported on the surface of steel 20 was used to obtain nanosize surface layers containing chromium and iron oxides dispersed in α- and γ-iron, as well as mixed oxides with a FeO · Cr2O3 spinel structure. Reduced metallic chromium is also found. Measurement of anodic potentiodynamic curves in neutral and weakly basic borate buffer solutions shows that the formed surface layers promote enhancement of corrosion stability of steel due to transition of the surface into a passive state.

Structure and Surface Layers of Mg-C Nanocomposites Produced by Ball Milling

X-ray diffractometry (XRD), X-ray photoelectron spectrometry (XPS), Auger electron spectrometry (AES) and transmission electron microscopy (TEM) were used to investigate the structure and surface layers properties of nanocomposites produced by the mechanical activation (ball milling) of elemental magnesium with carbon materials (amorphous carbon and graphite). Amorphous carbon was synthesized by electric discharge treatment in kerosene. It was shown that ball milling, the allotropic form of carbon materials, and features of hydrogenation have a considerable effect on the structure, surface layer properties, and hydrogen adsorption of a formed composition. XPS and Auger spectroscopy revealed the surface layer of the composite particles to be enriched with carbon. In addition, there were oxide layers on their surfaces due to the particles’ interaction with the environment.

Allowance for the background component in X-ray photoelectron and Auger electron spectroscopy

A simple and efficient method of subtraction of the nonlinear background in X-ray diffraction and Auger electron spectroscopy is suggested. The method has been verified using test samples of Fe-Ni alloys and oxides of transition metals of a known composition.

Investigation of oxidation and segregation processes at the surface of titanium nickelide

The chemical composition of the surface of the equiatomic alloy TiNi was studied using x-ray electron spectroscopy. It is shown that titanium nickelide shows a tendency toward titanium segregation at the free surface. After thermal action in vacuum and in air, the fraction of titanium atoms in the surface layer reaches 98% of the total content of titanium and nickel. Under heat treatment in air an oxidized layer forms at the surface whose main component is TiO2.

Synthesis of manganese dioxide by homogeneous hydrolysis in the presence of melamine

A new selective method for the synthesis of nanocrystalline manganese dioxide (α-, β-, and γ-MnO2) based on the reaction of potassium permanganate with 2,4,6-triamino-1,3,5-triazine (melamine) under hydrothermal conditions has been proposed. Effect of synthesis conditions on the phase composition of the products has been revealed. A new manganese-containing phase with layered structure has been prepared.

Corrosion and electrochemical behavior of nanoscale carbon layers deposited onto a surface of nonalloyed steel via pulsed laser deposition

Carbon films 5 to 7 nm thick with a graphite structure are obtained via high-speed laser exposure of ultrafine graphite powder distributed homogeneously on the surface of nonalloyed steel. Due to the created intermediate layer consisting of nonstoichiometric iron carbides, the obtained films have a high adhesion to the substrate. These films also exhibit high continuity and behave as ideally polarizable electrodes over an extended potential range in borate buffer solutions. Cathode and anode currents are much lower in the obtained graphite films than are those measured at the compact graphite materials. The deposited graphite layers completely stop the anodic dissolution of a steel substrate.

Determination of atomic pair correlation functions for nickel oxide films via extended energy-loss fine structure spectroscopy

The extended energy-loss fine structure (EELFS) spectra for pure nickel samples (M2,3 EELFS spectra), a NiO stoichiometric film (nickel M2,3 EELFS and oxygen K EELFS spectra), and an “inhomogeneous” oxide film (Ni-O system) on the surface of nickel have been obtained. The calculations of amplitudes and intensities of electron transitions are performed for the corresponding inner levels of atoms taking into account the multipolarity of the excitation of inner atomic levels by an electron impact. The normalized oscillating components are extracted from EELFS spectra using the results of calculations. Close agreement between experimental results and theoretical data obtained for test Ni samples and NiO films indicate that the theoretical approaches applied to the description of EELFS spectra and the results of calculations are good approximations. Atomic pair correlation functions are obtained from the experimental normalized oscillating components of EELFS spectra with the use of the Tychonoff regularization technique.

Composition separation in the surface layers of a Ni-Cu foil during ion implantation

The effect of ion implantation on the composition and mechanical properties of rolled Ni-Cu foils is studied. The formation of a non-monotonic oscillating dependence of the chemical composition on depth associated with a presumable change in the defect structure of the material has been observed. Possible mechanisms of the observed phenomena are proposed.

Dihydronitrilotris(methylenephosphonato)dimercury(II)mercury(I) [(Hg 2 I )Hg II N(CH 2 PO 3 ) 3 H 2 ]: Synthesis and Structure

Heterovalent complex [(Hg2I)HgIIN(CH2PO3)3H2] is synthesized by the reaction of mercury amidochloride HgIINH2Cl with nitrilotris(methylenephosphonic acid) N(CH2PO3)3H6. The gray crystals with metallic luster are monoclinic and described by the space group P21/c, Z = 4, a = 8.2988(7), b = 22.3149(15), c = 7.2188(6) Å, and β = 115.419(11)°. The Hg(II) atom is coordinated at vertices of a distorted octahedron, and the Hg2I group has the configuration of a strongly distorted trigonal prism. Seven donor centers of the ligand, six of the nine oxygen atoms, and one nitrogen atom are involved in the coordination of the mercury atoms. The crystal packing includes layers formed by the two-dimensional connection of the mercury atoms and ligand molecules linked by the van der Waals forces and weak hydrogen bonds only (CIF file ССDC no. 1559444).