Polymorphic Phase Transition and Piezoelectric Performance of BaTiO3-CaSnO3 Solid Solutions

Abstract

BaTiO3-based piezoelectric ceramics have attracted considerable attention in recent years due to their tunable phase structures and good piezoelectric properties. In this work, the (1 − x)BaTiO3−xCaSnO3 (0.00 ≤ x ≤ 0.16, abbreviated as BT−xCS) solid solutions, were prepared by traditional solid-state reaction methods. The phase transitions, microstructure, dielectric, piezoelectric, and ferroelectric properties of BT-xCS have been investigated in detail. The coexistence of rhombohedral, orthorhombic, and tetragonal phases near room temperature, i.e., polymorphic phase transition (PPT), has been confirmed by X-ray diffraction and temperature-dependent dielectric measurements in the compositions range of 0.06 ≤ x ≤ 0.10. The multiphase coexistence near room temperature provides more spontaneous polarization vectors and facilitates the process of polarization rotation and extension by an external electric field, which is conducive to the enhancement of piezoelectric response. Remarkably, the composition of BT-0.08CS exhibits optimized piezoelectric properties with a piezoelectric coefficient d33 of 620 pC/N, electromechanical coupling factors kp of 58%, kt of 40%, and a piezoelectric strain coefficient d33* of 950 pm/V.

Tailored electrostrain and related properties in (1 − x)BaTiO3–xSrSnO3 Pb‐free electroceramics

“…The grain size monotonously decreased from ∼21 μm ( x = 0.025) to ∼15 μm ( x = 0.15) with an increase in SrSnO 3 content, as shown in Figure 2F. This shows that the incorporation of Sn‐hindered grain growth during sintering and similar effects on the sintering behavior of BaTiO 3 have also been reported in the literature 31–33 . Notably, the grain‐size distribution became narrower with increase in x , and relatively broad grain size distributions were observed up to x = 0.075; however, the distributions exhibited a clear single peak near the average grain size for x = 0.1 and 0.15, and the paraelectric C phase became the major phase, as shown in Table 1.…”

“…Notably, the grain‐size distribution became narrower with increase in x , and relatively broad grain size distributions were observed up to x = 0.075; however, the distributions exhibited a clear single peak near the average grain size for x = 0.1 and 0.15, and the paraelectric C phase became the major phase, as shown in Table 1. Therefore, the broad grain size distributions could be a result of the coexistence of the T and O phases 32 …”

“…Therefore, the broad grain size distributions could be a result of the coexistence of the T and O phases. 32 be attributed to a diffuse phase transition. The dispersive behavior was most clearly observed for x = 0.15, where only a paraelectric C phase exists.…”