Effects of Oxide Additives on the Phase Structures and Electrical Properties of SrBi4Ti4O15 High-Temperature Piezoelectric Ceramics

Abstract

In this work, SrBi4Ti4O15 (SBT) high-temperature piezoelectric ceramics with the addition of different oxides (Gd2O3, CeO2, MnO2 and Cr2O3) were fabricated by a conventional solid-state reaction route. The effects of oxide additives on the phase structures and electrical properties of the SBT ceramics were investigated. Firstly, X-ray diffraction analysis revealed that all these oxides-modified SBT ceramics prepared presented a single SrBi4Ti4O15 phase with orthorhombic symmetry and space group of Bb21m, the change in cell parameters indicated that these oxide additives had diffused into the crystalline lattice of SBT and formed solid solutions with it. The SBT ceramics with the addition of MnO2 achieved a high relative density of up to 97%. The temperature dependence of dielectric constant showed that the addition of Gd2O3 could increase the TC of SBT. At a low frequency of 100 Hz, those dielectric loss peaks appearing around 500 °C were attributed to the space-charge relaxation as an extrinsic dielectric response. The synergetic doping of CeO2 and Cr2O3 could reduce the space-charge-induced dielectric relaxation of SBT. The piezoelectricity measurement and electro-mechanical resonance analysis found that Cr2O3 can significantly enhance both d33 and kp of SBT, and produce a higher phase-angle maximum at resonance. Such an enhanced piezoelectricity was attributed to the further increased orthorhombic distortion after Ti4+ at B-site was substituted by Cr3+. Among these compositions, Sr0.92Gd0.053Bi4Ti4O15 + 0.2 wt% Cr2O3 (SGBT-Cr) presented the best electrical properties including TC = 555 °C, tan δ = 0.4%, kp = 6.35% and d33 = 28 pC/N, as well as a good thermally-stable piezoelectricity that the value of d33 was decreased by only 3.6% after being annealed at 500 °C for 4 h. Such advantages provided this material with potential applications in the high-stability piezoelectric sensors operated below 500 °C.

Enhanced electrical properties of Cr2O3 addition NBT‐based high‐temperature piezoelectric ceramics

“…Notably, recent studies have reported that Cr 2 O 3 has similarly improved the piezoelectric properties of BLSF piezoelectric materials. For instance, among modifications with MnO 2 , CeO 2 , and Cr 2 O 3 , that with Cr 2 O 3 provided the best improvement in the d 33 and thermal stability of SrBi 4 Ti 4 O 15 8 . In addition, Cr 2 O 3 addition had positive effects on the piezoelectric properties of W 6+ ‐doped Bi 4 Ti 3 O 12 and CaBi 2 Nb 2 O 9 , with an increase in the d 33 values to 28 9 and 15 pC/N 3 , respectively.…”

Boosting of Magnetic, Ferroelectric, Energy Storage Efficiency, and Piezoelectric Properties of Zn Intercalated SrBi4Ti4O15-Based Ceramics

“…The suitable A and B -site dopants for SBT have recently shown interesting behaviors regarding the piezoelectric, ferroelectric, and pyroelectric properties. Recently, Wang et al have studied the piezoelectric and dielectric properties of SBT ceramics with the addition of different oxides, where the modified Sr 0.92 Gd 0.053 Bi 4 Ti 4 O 15 + 0.2 wt% Cr 2 O 3 has shown the best merits with piezoelectric d 33 ~ 28 pC/N [ 17 ]. Ramana et al have reported the high remnant polarization ( P r ) of ~9.2 µC/cm 2 for the A -site doping of Pb in SBT (Sr 1−x Pb x Bi 4 Ti 4 O 15 ) ceramics [ 18 ].…”

Structural, Dielectric Properties and Conduction Mechanism of SrBi4Ti4O15 Ceramics

“…SBT ceramic has an orthorhombic structure (space group: A2 1 am) and above the curie temperature T c =530 • C, it changes to a tetragonal structure (space group: I4/mmm) (1)(2)(3)(4) . The Bi and oxygen vacancies will be formed for SBT ceramics during the process of sintering, the oxygen vacancy maintains the neutral charge (5,6) . The oxygen vacancy may cause due to enhanced leakage current, impeding the displacement of the Ti 4+ ion, screening the electric field near the space charge region, and trapping of charge carriers (7,8) .…”

“…Some previous literature reported that substituting the A and/or B-site of SBT will improve the ferroelectric properties and minimize the oxygen vacancies (9,10) . The effect of oxide additives like Gd 2 O 3 , CeO 2 , MnO 2, and Cr 2 O 3 on the phase structures and electrical properties of SBT ceramics were investigated by Shaozhao Wang et al (11) . The oxide additives improve the piezoelectric property of SBT (d 33 = 10 pC/N); SCBT-Cr and SGBT-Cr obtained a higher d 33 of 26 pC/N and 28 pC/N, respectively.…”