The thermal and radiation stabilities of the formulations based on ethylene–propylene–diene rubber (EPDM), which contain barium titanate (BaTiO₃) doped with lanthanum and cerium oxides, were investigated by chemiluminescence and mechanical testing. The contributions of these doped fillers are related to the surface interaction between the structural defects (doping atoms, i.e., lanthanum and cerium) implanted in the filler lattice and the molecular fragments formed during the progress of degradation. These composite materials present extended durabilities with respect to the references; the oxidation periods are a minimum of three times longer than the corresponding times for pristine polymers. This behavior is associated with the scavenging activity of dopants. Mechanical testing has demonstrated the contributions of doped filler to the improvement of tensile strength and elongation at break by the restructuration of the polymer phase. Scanning electron microscopy images revealed the densification of materials in the presence of doped barium titanates. All the investigations constitute valid proof for the qualification of BaTiO₃ doped with Ce as the more efficient stabilizer compared to the same inorganic filler doped with La.

This study presents an experimental investigation of the influence of dopant type and calcination temperature on BaTiO₃-based piezoceramics synthesized by a solid-state calcination process. The effects of Mn, Nb, La, and Ce dopants on the structural, morphological, and piezoelectric characteristics of powders calcined at 1000 °C and 1100 °C were systematically evaluated. In addition, two co-doped BaTiO₃ compositions, namely Mn–Nb and La–Nb, calcined at 1000 °C, were investigated in order to assess the combined effect of acceptor–donor and donor–donor doping strategies on microstructural evolution and structural stability. The synthesized powders were characterized by scanning electron microscopy (SEM), particle size analysis, energy-dispersive X-ray spectroscopy (EDS), elemental mapping, and X-ray diffraction (XRD), in comparison with a commercial BaTiO₃ reference powder. The piezoelectric response was assessed by correlating the structural modifications induced by doping with the estimated piezoelectric coefficient d₃₃, calculated as a function of the tetragonality ratio (c/a) and further correlated with the crystallite size. The results reveal significant variations in grain growth, dopant distribution, and crystallographic stability, highlighting the critical role of dopant chemistry and calcination temperature in tailoring the functional properties of BaTiO₃ for piezoelectric applications.

The Pb(Mg_1/3Nb_2/3)O₃-based ceramic system was obtained by using a modified variant of the conventional ceramic method in order to get pyrochlore-free compositions. Solid solutions obtained from Pb(Mg_1/3Nb_2/3)O₃ and Ln(Mg_1/2Ti_1/2)O₃ with Ln = Y3+, La³⁺, Pr³⁺, Nd³⁺ and Sm3+, were synthesized using a 3-step columbite precursor method and appropriate milling and sintering conditions. The structural phases of all sintered compositions were investigated in detail. The X-ray diffraction results demonstrate that all the samples possess a perovskite structure. The influence of dopant on the incorporation degree in the solid solutions was studied. The dielectric constants at three frequencies were measured and the influence of the dopant on these values was discussed.

In this study, four types of materials suitable for use as special insulation were produced. Polyvinylidene fluoride (PVDF) served as the polymer matrix, while PZT powders (a Pb(Zr_0.52Ti_0.48)O₃ system doped with Nb₅₊ and Sr₂₊) were used as the filler material; the method for producing these powders is also described. The mass concentrations, expressed as PVDF/PZT ratios, were 100/0, 95/5, 90/10, and 80/20. Characterization analyses and tests were conducted to verify the materials’ suitability as insulators. Specifically, the materials underwent structural (SEM and FTIR), chemical (EDS), mechanical, and dielectric testing (measuring tan δ, ε_r, ρ, and E_str). Additionally, resistance to degradation at the maximum operating temperature was evaluated through thermal resistance tests at 150 °C. Finally, the remaining service life prior to complete material degradation—and the consequent need for replacement—was determined. All characterization tests indicated that the composite material with a 5% PZT powder concentration—which exhibits the best structural, mechanical, dielectric, and thermal properties—represents the optimal composite variant for insulation applications. Potential applications for these materials include coatings for electric field grading and voltage control, as well as insulation for high-voltage transients and impulses.

In this paper B-oxide sintering process and Spark plasma Sintering (SPS) method is used to synthesize 0.88Pb(Zr_0.52Ti_0.48)O₃ – 0.12Pb(Mn_1/3Sb_2/3)O₃ – x at%Pr complex system where x = 0 and 0.02. The sintering temperature used in the SPS technique is considerably lower than that used in the B-oxide method (200 to 400^oC) with significant decrease of the duration of the sintering route, arriving to some minutes instead of some hours. The aim of the study is the investigation of the effect of sintering technique on the dielectric and ferroelectric properties of such piezoelectric materials. The properties of the developed ceramic materials were determined: the development of crystalline phases was investigated by X-ray diffraction technique and the microstructural behavior by scanning electron microscopy was observed. The composition obtained by the SPS technique shows a lower remnant polarization and maximum strain, as well as a higher coercive field, compared to the those obtained using the same composition produced by B-oxide method.