The bauxite ores of Kazakhstan were analyzed using Mössbauer spectroscopy, X-ray diffraction and an X-ray fluorescence analysis. Experimental data on the structural–phase composition of bauxites were obtained, and the features of the iron-bearing minerals within them were revealed. The studied bauxites were high in iron. The magnetic part of bauxite was mainly represented by aluminohematite with a concentration of C_Al = 3.34–5.73 at.%, alongside goethite in small amounts. The predominant phase in the bauxite samples was the alumina-bearing mineral gibbsite with a well-crystallized monoclinic lattice. The main siliceous mineral of bauxite is kaolinite, which showed distorted octahedral positions in a number of samples. Siderite amounts were found to vary in the range of 0–15 at.% in the present iron-bearing minerals. Ilmenite was also present in the bauxite of some deposits; anatase was found in all bauxites and was the final product of ilmenite decomposition in the weathering crust.

Mixed transition metal sulfides are promising materials for positive electrodes of asymmetric supercapacitors because they have a large potential for increasing the electrical characteristics of these devices. The paper presents the results of a study of a material based on spinel CuCoNiS_xO_4−x with both sulfide and oxide sublattices, prepared by a one-step hydrothermal method directly on nickel foam, forming an array of whiskers. Electrochemical studies showed that a positive electrode, CuCoNiS₂O₂, exhibited a high specific capacitance of 3612 F g⁻¹ at a current density of 1 A g⁻¹. The assembled asymmetric supercapacitor with activated carbon as a negative electrode achieved a specific capacitance of 133.5 F g⁻¹ at 1 A g⁻¹ and a potential window of 1.7 V. Its energy density was 53.6 Wh kg⁻¹ at a power density of 805 W kg⁻¹ and the power density reached 17,000 W kg⁻¹ at an energy density of 18.9 W h kg⁻¹. The assembled device exhibits 52% of capacitance retention after the 20,000 cycles at a current density of 10 A g⁻¹ with 97% coulombic efficiency. These results demonstrate that the CuCoNiS_xO_4−x system is competitive with other quaternary transition metal sulfides, and this type of spinel is a perspective electrode material for high-performance supercapacitors.

Studies of the mineralogical composition were carried out, and the features of the clays from the deposits of Kazakhstan were established using Mössbauer spectroscopy (MS) and X-ray diffraction analysis (XRD). According to the XRD results, all the samples were mixed-layer clays of the kaolinite–illite type. The lattice parameters of the kaolinite were determined, and it was shown that its structure was disordered and contained a certain amount of impurity in some of the clay samples. A special feature of two of the samples was the additionally identified muscovite polytype 2M₁. The spectra of the iron-containing clays were amenable to being resolved into separate components, with similar Mössbauer parameters of the kaolinite, muscovite, illite, and glauconite. The oxidation state of the iron was determined using MS. The predominant part of paramagnetic iron in most samples was in the trivalent state. The primary minerals contributing to Fe²⁺ were illite and muscovite. The results obtained during the study of the clay samples with complex mineralogical compositions using MS and XRD methods both complemented one another and were found to be in good agreement.

This study aimed to develop a technology for synthesizing non-degrading porous coatings that remain stable under the conditions of outer space. Using the magnetron sputtering method, we obtained vanadium–lead system coatings over a wide range of mutual concentrations from 6 to 44.9 at. % Pb. X-ray and electron microscopic studies were conducted on the obtained coatings. As a result of the research, a dependence of the film structure on changes in the lead concentration in vanadium was demonstrated. A correlation between the lead concentration in vanadium, the size of the resulting crystallites of solid solutions, and the change in the lattice parameter of the solid solution depending on the lead concentration in the coating was identified. A new possibility of producing porous vanadium coatings through vacuum annealing of the obtained alloy-based coatings in the V-Pb system was shown.

Solid solutions of tellurium in cadmium, cadmium in tellurium, and cadmium in cadmium telluride synthesized during sputtering are formed for the first time by ion-plasma sputtering and the...