Phase equilibria and electrical properties of barium-containing relaxor-based solid solutions

Abstract

We have studied the effect of modification with Ba on the phase composition, structure, and elec trical properties of ceramic samples of Pb (1 -x) Ba x (Mg 1/3 Nb 2/3 ) m (Zn 1/3 Nb 2/3 ) y (Ni 1/3 Nb 2/3 ) n Ti z O 3 (0 ≤ x ≤ 0.15) solid solutions and investigated phase equilibria in this system in the range 0 ≤ x ≤ 0.15. The results indicate that a tetragonal and a low symmetry phase coexist in the composition range 0 ≤ x ≤ 0.05, a pseudocubic phase exists in the range 0.05 < x < 0.10, and a cubic phase exists in the range 0.1 ≤ x ≤ 0.15. We propose a scheme of solid solution formation according to which partial barium substitution for lead in the range 0 ≤ x ≤ γ (where γ is structural nonstoichiometry) causes the Pb ions to leave distorted octahedra. For x > γ, Ba 2+ sub stitutes for Pb 2+ on the cuboctahedral site. The sintering temperature is shown to influence the phase com position of the modified ceramics. We demonstrate, that varying the Ba content of the solid solutions, one can obtain a series of materials with a wide range of electrical parameters (ε/ε 0 = 2880-11000, K p = 0.07-0.43, and Q m = 48-8300) and potential applications in hydroacoustics, piezoelectric motors, and capacitor tech nology.

Impact of Ba2+ on Structure and Piezoelectric Properties of PMN–PZN–PNN–PT Ceramics Near the Morphotropic Phase Boundary

“…Earlier it was shown that the introduction of 5 mol% Ba 2+ in PZN–PMN–PNN–PT leads to stabilization of the perovskite structure (the traces of pyrochlore phase disappear on X‐ray diagrams), changes in the phase composition of the studied ceramics, significant increase in the values of their piezoelectric and dielectric responses and modifications of microstructure . A preliminary phase diagram of this system with variation in the barium content was constructed . However, the establishment of the MPB on the phase diagram of the system required clarification.…”

“…28 A preliminary phase diagram of this system with variation in the barium content was constructed. 29 However, the establishment of the MPB on the phase diagram of the system required clarification.…”