Ferroelectric ceramic materials based on the (1-x-y) NaNbO₃-xKNbO₃-yCd_0.5NbO₃ system (x = 0.05–0.65, y = 0.025–0.30, Δx = 0.05) were obtained by a two-stage solid-phase synthesis followed by sintering using conventional ceramic technology. It was found that the region of pure solid solutions extends to x = 0.70 at y = 0.05 and, with increasing y, it narrows down to x ≤ 0.10 at y = 0.25. Going out beyond the specified concentrations leads to the formation of a heterogeneous region. It is shown that the grain landscape of all studied ceramics is formed during recrystallization sintering in the presence of a liquid phase, the source of which is unreacted components (Na₂CO₃ with T_melt. = 1126 K, K₂CO₃ with T_melt. = 1164 K, KOH with T_melt. = 677 K) and low-melting eutectics in niobate mixtures (NaNbO₃, T_melt. = 1260 K, KNbO₃, T_melt. = 1118 K). A study of the electrophysical properties at room temperature showed the nonmonotonic behavior of all dependences with extrema near symmetry transitions, which corresponds to the logic of changes in the electrophysical parameters in systems with morphotropic phase boundaries. An analysis of the evolution of dielectric spectra made it possible to distinguish three groups of solid solutions: classical ferroelectrics (y = 0.05–0.10), ferroelectrics with a diffuse phase transition (y = 0.30), and ferroelectrics relaxors (y = 0.15–0.25). A conclusion about the expediency of using the obtained data in the development of materials and devices based on such materials has been made.

The reasons for the high electrical conductivity of bismuth ferrite due to its natural composite structure, structural non-stoichiometry, redox processes, and the boundary position in the perovskite family have been considered. It has been shown that it is possible to significantly (2–3 orders of magnitude) reduce the conductivity of BiFeO₃ by introducing large-sized ions of rare-earth elements (REE: La, Pr, Nd, Sm, Eu, Gd with 0.94 ≤ $\overline{R}$ ≤ 1.04 Å) in amounts of up to 10 mol %. An interpretation of the observed effects has been given. A consideration about the appropriateness of taking into account the presented results when developing devices using materials of the BiFeO₃/REE type has been expressed.

We investigated and presented our results for the dependence of the characteristics of the crystalline and grain structures of the PCR-13 material (based on the lead zirconate titanate (PZT) system), which was sintered in various ways, on the regulations for its preparation. The data from the microfluorescence analysis of the surface of ceramic materials were provided, which allowed us to state that micro X-ray fluorescence spectrometry (MICRO–XRF), supplemented by mathematical statistics, allows us to trace even small changes in the chemical composition of ceramic samples, reliably characterize the degree of surface homogeneity and provide strict mathematical conclusions related to the reproducibility of the properties of manufactured piezoelectric ceramic materials. Based on the obtained data, the optimal conditions for ceramics have been selected, which ensure homogeneity, high-density structure and reproducibility of the characteristics. This allows us to reliably use the material in frequency-selective equipment.

The investigation results of the processes of phase formation in barium niobate, strontium, and their solid solutions in the conditions of the variability of the thermodynamic background are presented. The formation of a grain landscape and dielectric properties (including relaxation phenomena) in the solid solutions of strontium niobate and their solid solutions and the establishment of regularities in the formation of radio-absorbing properties in them are studied.

Solid solutions of the ([equation]) (0.02 ⩽ α1 ⩽ 0.36, 0.0073 ⩽ α2⩽ 0.1339) system with the ratio of Sr and Ba chosen so as to exclude the influence of the size factor on the lead titanate structure...