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.

The effect of implanting ⁵⁷Fe ions on the crystal structure of Nb–Zr alloys has been studied using Mössbauer spectroscopy on ⁵⁷Fe nuclei and X-ray diffraction. As a result of implantation, a metastable structure was formed in the Nb–Zr alloy. The XRD data indicated a decrease in the crystal lattice parameter of niobium; that is, there was a compression of the niobium planes when implanted with iron ions. Mössbauer spectroscopy revealed three states of iron. The singlet indicated a supersaturated Nb(Fe) solid solution; the doublets characterized the diffusion migration of atomic planes and crystallization of voids. It was shown that the values of the isomer shifts in all three states did not depend on the implantation energy, which indicates the invariance of the electron density on the ⁵⁷Fe nuclei in the studied samples. The resonance lines of the Mössbauer spectra were significantly broadened, which is typical for materials with low crystallinity and a metastable structure that is stable at room temperature. The paper discusses the mechanism of radiation-induced and thermal transformations in the Nb–Zr alloy, which leads to the formation of a stable well-crystallized structure. A Fe₂Nb intermetallic compound and the Nb(Fe) solid solution formed in its near-surface layer, while Nb(Zr) remained in the bulk.

The austenitic–martensitic transformation in austenitic–ferritic duplex stainless steel CF8 subjected to cold plastic deformation with a deformation degree ε = 10–95% is studied here using transmission Mössbauer spectroscopy (MS), conversion electron Mössbauer spectroscopy (CEMS), and X-ray diffraction (XRD) methods. It is assumed that the α′-martensite phase appeared at ε > 10%. The CEMS results showed that the formation of α′-martensite occurred most intensively in the near-surface layers of the steel, distributing in depth with the growth of the deformation degree. The volume fraction of the α′-martensite was determined based on the results of calculations carried out via the MS and XRD methods, and a good correlation was observed. A modified Olson–Cohen model was proposed to determine the dependence of the amount of α′-martensite on the deformation degree ε. The coefficients included in the Olson–Cohen expression were found.

Nanoscale coatings formed by thermal vacuum deposition of metal on an aluminum substrate have been investigated by Mössbauer spectroscopy, X-ray diffraction (XRD) analysis, and electron microscopy. The film coatings have been grown by depositing enriched ⁵⁷Fe in a magnetron vacuum chamber at a residual atmospheric pressure. It is shown that carbon penetration occurs over grain boundaries and inhomogeneities of interboundary formations, and an amorphous phase is formed during deposition of fine-grained ⁵⁷Fe. After annealing at a temperature of 500°C, the amorphous structure is crystallized and a monophase (cementite Fе₃С) is formed. High-temperature annealing leads to the formation of ferrite α-Fе(C) and graphite due to the decrease in the Fе₃С content, according to the equilibrium phase diagram of the Fе–C system.

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.

The method of Mössbauer spectroscopy at 57Fe nuclei was used to study the structure and phase state of a three-layered Be-Fe-Be system after irradiation with helium and krypton ions and subsequent iso