Isomorphism problems in lead-barium titanate

A complex study of Pb1-xBaxTiO3 solid solutions (0.00 <= x <= 1.00) made using conventional ceramic technology have been performed. By the method of X-ray diffraction, a deviation of the concentration dependences of the structural parameters from additivity was established and the degradation of the diffraction peaks in the interval 0.10 < x < 0.9 is shown. Energy dispersive X-ray (EDX) analysis of the samples revealed regions enriched in Pb or Ba. An analysis of X-ray photoelectron spectra showed that in the decomposition of the Pb4f spectrum contains components characteristic of the Ti2PbC compound. The study of the dielectric, piezoelectric, and mechanical properties revealed in the range 0.3 <= x <= 0.8 the diffuse ferroelectric phase transition, of the dispersion of the relative permittivity epsilon/epsilon(0), as well as the appearance of the second frequency-dependent maximum on the temperature dependence of the dielectric loss tangent. A correlation between the diffuseness degree of the ferroelectric phase transition and the spreading in chemical composition in the samples is shown. Based on the data of the study, it was concluded that there is no continuous series of solid solutions in the Pb1-xBaxTiO3 system. (C) 2020 Elsevier B.V. All rights reserved.