Effects of (Li, Ce, Y) co-substitution on the properties of CaBi2Nb2O9 high temperature piezoceramics

Self Cite

CaBi2Nb2O9 (CBN)‐based high Curie temperature piezoelectric ceramics with formula Ca0.8‐xSrx(Li0.5Ce0.15Bi0.35)0.2Bi2Nb1.94Ta0.04W0.02O9 were prepared by conventional solid‐state reaction method. The effects of strontium substitution for calcium in CBN pseudo‐perovskite structure A‐site were systematically studied. Results showed that the addition of Sr2+ ions lead to an improvement of the tetragonality of lattice structure, which resulted in an enhancement of piezoelectric and ferroelectric properties together with high Curie temperature TC and good resistance to thermal depolarization. The analysis of dielectric spectrums revealed that the space charge polarization induced an additional dielectric anomaly occurred below TC. The composition with x = 0.025 showed good integrated performance, the piezoelectric coefficient d33 and TC were ~17.5 pC/N and ~917°C, respectively. Even though the as‐studied ceramics underwent high depolarizing temperature reached up to 875°C, d33 decreased by 8% merely. The remanent polarization 2Pr and the resistivity ρ at 650°C were on the order of ~10 μC/cm2 and 3 × 105 Ω cm, respectively.

Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Enhanced electrical properties related to structural distortion of CaBi₂Nb₂O₉‐based piezoelectric ceramics

Xie

Zhong

et al. 2018

Self Cite

“…The aerospace, aircraft, and nuclear power industries have an indispensable demand for relevant electronic devices, and Aurivillius ferroelectrics have attracted much attention for their brilliant application prospect in high‐temperature region, owing to their high Curie temperature ( T C ) and large resistivity . The general formula of Aurivillius ferroelectrics is (Bi 2 O 2 ) 2+ (A m −1 B m O 3 m + 1 ) 2− , where A is a mono‐, di‐, or trivalent element (or combination) with dodecahedral coordination.…”

Section: Introductionmentioning

confidence: 99%

Enhanced thermal stability of (NaCe)‐multidoped CaBi₂Nb₂O₉ by A‐site vacancies‐induced pseudo‐tetragonal distortion

Liu

Ren

et al. 2018

Self Cite

Although A‐site codoping of alkali metal and rare‐earth elements are known to effectively promote the d33 of CaBi2Nb2O9 (CBN), its thermal depoling behavior cannot be well promised. In this work, piezoelectricity of CBN was effectively promoted by (NaCe) modification, and its thermal instability was caused by the lattice evolution from orthorhombic structure to pseudo‐tetragonal structure during thermal depoling process. A‐site vacancies could induce pseudo‐tetragonal distortion in Ca0.92(Na0.5Ce0.5)0.08Bi2Nb2O9 ceramic, which obviously enhanced the thermal stability of lattice by reducing the rotation of the Nb–O octahedron during the thermal depoling process, as compared with orthorhombic structure, thereby weakening the swing of spontaneous polarization (Ps) and promoting the thermal depoling performance. Consequently, good thermal stability was obtained (remained 92% of initial d33 after depoling at 600°C). Moreover, dominant role of oxygen vacancies in the electrical conduction and relaxation process promised that the introduction of small amount of A‐site vacancies would not influence the electrical properties obviously.

“…29 In general, lower t value corresponds to higher T C in BLSFs. 30 The substitutions of Ti 4+ (0.605 Å) with Ta 5+ (0.64 Å) and Cu 2+ (0.73 Å) will give rise to a decrease in tolerance factor (t), which might be responsible for increasing T C in the samples with lower doping concentration. On the other hand, the B-site cations with the higher nd 0 electron orbit generally are known to decrease the T C .…”

Section: Resultsmentioning

confidence: 99%

Large enhancement of piezoelectric properties and resistivity in Cu/Ta co‐doped Bi₄Ti₃O₁₂ high‐temperature piezoceramics

Chen

Sheng

et al. 2019

In this study, the electrical properties of Bi4Ti3O12‐based Aurivillius‐type ceramics were tailored by a B‐site co‐doping strategy combining high valence Ta5+ and low valence Cu2+. A series of Bi4Ti3−x(Cu1/3Ta2/3)xO12 (BTCT) (x = 0, 0.005, 0.01, 0.015, 0.02, 0.025, and 0.03) ceramics were prepared by the conventional solid‐state reaction method. The effect of Cu/Ta co‐doping on the crystal structure, microstructure, dielectric properties, piezoelectric properties, ferroelectric properties, and electrical conductivity of these ceramics was systematically investigated. Co‐doping significantly enhanced the piezoelectric properties and DC electrical resistivity of the resulting composites. The optimized comprehensive performances were obtained at x = 0.015 with a large piezoelectric coefficient (34 pC/N) and a relatively high resistivity of 9.02 × 106 Ω cm at 500°C. Furthermore, the ceramic also exhibited stable thermal annealing behaviors and excellent fatigue resistance. The results of this study demonstrated great potential of the Cu/Ta co‐doped Bi4Ti3O12 ceramics for high‐temperature piezoelectric device applications.