Vol 43, No 1 (2017)

The theoretical and methodological data on the magnetochemistry of low-magnetic glass and crystalline materials, including chalcogenides, are presented. Based on the methods of the magnetochemistry of glass and crystalline materials, the conclusions about the parameters of chemical bonds in these materials, the distribution of substances added to them, the presence or absence of chemical ordering, and the concentration of intrinsic paramagnetic centers have been made.

X-ray fluorescence of lithium borate glass with various additives is studied. The possibility of the mutual influence of glass components, as well as equipment, on the results of X-ray analysis is shown. The conditions under which this method can be used for analytical purposes are formulated.

The results of the synthesis and study of white glass-ceramic enamel coatings for the protection of steel products based on R₂O–RO–B₂O₃–Al₂O₃–SiO₂–TiO₂–P₂O₅–F^–system are considered. A number of glass-enamel compositions is developed. The crystallization features are revealed for white covercoat glassceramic enamel coatings; and the conditions preventing the anatase-to-rutile modification transition are determined. The influence of dopants upon the crystallization of white enamels is stuedied. The whiteness and spectrophotometric characteristics of the shadings are determined for white enamels using the spectrophotometric method and the RGB color model. It is proved that the synthesized covercoat glass-enamel coatings for steel products meet all the requirements of the technical specifications of the Russian State Standard GOST R 52569-2006 Frits.

Thin silicon carbonitride SiC_xN_y films are synthesized by means of plasma enhanced chemical vapor deposition using an organosilicon compound such as bis(trimethylsilyl)ethylamine EtN(SiMe₃)₂ as the precursor in a mixture with hydrogen. The chemical composition and properties of the films are characterized by a set of modern research methods such as IR, Raman, and energy dispersive spectroscopy; ellipsometry; scanning electron microscopy; and spectrophotometry. The growth rate, chemical composition, and optical properties of the films have been studied depending on the synthesis temperature in the range from 373 to 1073 K. It is found that the substrate temperature exerts a significant effect on the growth kinetics, surface morphology, physicochemical properties, and functional characteristics of the films. Low temperature SiC_xN_y films have high transparency in the visible and infrared regions of the spectrum. Varying the parameter of synthesis allows one to obtain layers with different values of the refractive index (1.50–2.50).

Silver nanoparticles have been fabricated by the method of chemical reduction in solution using different types of stabilizers: an organic low-molecular compound—sodium dioctyl sulfosuccinate (AOT)— and a natural biologically active substance—antimicrobial cationic polypeptide lysozyme. According to studies of the produced hydrosols, the average size of the shell-coated particles is 20–25 nm. The biological activity of the obtained bioconjugates toward Gram-negative (Escherichia coli ML35p, Pseudomonas aeruginosa (clinical isolate)) and Gram-positive (Listeria monocytogenes EGD (АТСС ВАА-679), MRSA ATCC 33591 (Staphylococcus aureus resistant to methicillin)) bacteria has been investigated by the methods of radial diffusion in an agarose gel and serial dilution in a liquid nutritional medium. It has been established that the antimicrobial activity of the bioconjugates depends on the nature of the used stabilizer.

Crystalline zirconium phosphates with the langbeinite structure containing macroquantities of elements that imitate high-level radioactive waste (HLRW) (Cs 4.6 wt %, Sr 6.2 wt %, La 10.0 wt %, or U⁴⁺ 11.6 wt %) have been synthesized. To impart finely the dispersed materials with the necessary rheological properties, they have been made more compact with the addition of an 2.4–4.4 wt % aluminophosphate binder. The rate of leaching (logR) of the prepared langbeinite samples in distilled water at room temperature for 100 days decreased to–6.1 (Cs),–5.4 (Sr),–5.5 (La), and–5.6 (U) g/(cm² day) with a noticeable trend toward further reduction, which meets, in practical terms, the requirements for the matrix material used for HLRW management. The samples’ axial compression strengths after leaching tests varied from 600 to 1100 kg/cm².

Single phased Sr substituted BaTiO₃ ceramics were synthesized by a sol-gel route and were found to crystallise in tetragonal symmetry with P_4mm space group using rietveld refinement. With increase in Sr content the tetragonality was reduced to pseudocubic and the Curie temperature (T_c) decreased with a rate of 3.33 K/mol %. This transition temperature has been determined by studying the thermal evolution of Cole- Cole diagrams (ε'' vs ε'). Effects of Sr content (x) and sintering time (4 and 8 h) on density, crystalline structure and piezoelectric properties were also investigated.

Using the method of crystallochemical analysis (the TOPOS program package), the 14 most promising and stable structures of lithium manganese (iron) silicate compounds have been selected based on the data on 132 experimentally received and predicted compounds (Materials Project resource).

The problem of modifying thermal and photolytic properties by using carbon nanoparticles is discussed for an energy-saturated (5-nitrotetrazolato-N²) pentaammin-cobalt(III) perchlorate metal complex. The interpretation of the experimental data using the conception of minor structural transformations is proposed.