Excellent thermal stability and aging behaviors in BiFeO₃‐BaTiO₃ piezoelectric ceramics with rhombohedral phase

Abstract

BiFeO3‐BaTiO3 (BF‐BT) solid solutions are lead‐free candidates for high‐temperature piezoelectric applications. BF‐BT ceramics with compositions near the morphotropic phase boundary (MPB) separating rhombohedral (R) and pseudo‐cubic (PC) phases were fabricated by the conventional high temperature sintering method, and their thermal stability and aging properties were studied in detail. BF‐BT ceramics with rhombohedral (R) phase show much better thermal stability and aging properties than those with pseudo‐cubic (PC) or coexistence of PC and R phases. The thermal degradation and aging rates of BF‐BT ceramics with R phase are on the order of 1% and 1.2% per decade, respectively. X‐ray diffraction results reveal that the domain state of poled rhombohedral BF‐BT ceramics is stable up to its Curie temperature, which is responsible for the high thermal stability. The Rayleigh analysis shows that the low aging rate is attributed to the low domain wall contribution to the overall piezoelectric response. The high thermal stability and low aging rates indicate that the lead‐free BF‐BT ceramics with R phase are potential candidates for sensor and transducer applications over a broad temperature range.

Dielectric, ferroelectric, and piezoelectric properties of Gd-modified CaBi2Nb2O9 high Curie temperature ceramics

“…These piezoelectric sensors usually withstand high temperature of 500 °C or higher. To meet the requirements of these applications, piezoelectric materials must possess high piezoelectric performance and high electrical resistivity as well as high Curie temperature [1][2][3][4][5][6][7][8][9][10][11][12].…”

Enhanced aging behaviors and electric thermal stabilities in 0.75BiFeO3–0.25BaTiO3 piezoceramics by Mn modifications

“…[1][2][3][4][5][6][7] It is worth noting that BF-BT solid solution not only has a continuous phase transition but also possesses a morphotropic phase boundary (MPB) where the content of BT is between 0.25~0.40. [8][9][10][11][12] In the BF-BT piezoceramics system, 0.75BF-0.25BT ceramics near the MPB has attracted intensive investigation due to its high Curie temperature (>560℃) and excellent electric properties. The 0.75BF-0.25BT solid solution possessed perovskite phase structure with rhombohedral phase structure (R3c space group), showed excellent temperature stabilities when compared with BF-BT piezoceramics with pseudo-cubic phase (Pm3m space group) and coexistence of pseudo-cubic phase and rhombohedral phase (Pm3m and R3c space group).…”

High‐temperature BiFeO3–PbTiO3‐Ba(Zr,Ti)O3 ternary ceramics with excellent piezoelectricity

“…The temperature sensitivity coefficient η given in Figure 8B was calculated by the following equation.where ( d 33 ) T and ( d 33 ) 200°C are of the piezoelectric coefficient at the measurement temperature T and 200°C, respectively. It can be seen that the d 33 values change slightly with the rise of annealing temperatures up to 400°C, which is only about 50°C lower than the phase transition temperature T c , and the η value is maintained at ±10% in the temperature range of 30°C–400°C, which is due to the stable domain structure at the elevated annealing temperature 26,49 . It is concluded that the piezoelectric properties of BF‐ x PT‐0.13BZT ternary ceramics show an excellent thermal stability due to their high Curie temperature and large coercive fields.…”

“…It is known that the large signal results mainly from both intrinsic and extrinsic contributions. The intrinsic effect is dominated by the lattice distortions and reversible domain wall switching, while the extrinsic contribution is a result of irreversible non‐180° domain‐wall motion and phase transition 48,49 . The lower lattice distortions are beneficial to the domain switching and thus the improvement of field induced strains 50,51 …”