Enhanced piezoelectricity in Na and Ce co-doped CaBi ₄Ti ₄O ₁₅ ceramics for high-temperature applications

Abstract

The Na and Ce co-doped CaBi4Ti4O15 (CBT) Aurivillius ceramics in a Ca1-x(Na0.5Ce0.5)xBi4Ti4O15 (CNCBT, x = 0, 0.03, 0.05, 0.08 and 0.12) system were synthesized by the conventional solid-state sintering method.All compositions show a single-phase orthorhombic (space group A21am) structure at room temperature. The shift of the Curie point Tc towards lower temperatures on doping results from the increased tolerance factor t.The substitution-enhanced ferroelectric performance with large maximum polarization and facilitated domain switching is evidenced by the developed P-E and I-E hysteresis loops. The piezoelectric coefficient d33 (20.5 ± 0.1 pC/N) of the x = 0.12 sample is about four times larger than that of pure CBT. The improved piezoelectric properties can be attributed to the high remnant polarization and relatively high permittivity. In addition, multisized (micron and sub-micron) domain structures were observed in the CNCBT ceramics by piezoelectric response microscopy. The multiple sized ferroelectric domain structure with smaller domains is beneficial to the easy domain switching, enhanced ferroelectric performance and improved piezoelectric properties of the CNCBT ceramics. The designed Aurivillius-phase ferroelectric ceramics with the Curie point around 765 °C and high d33 are suitable for high-temperature piezoelectric applications.

Single-Phase, Large Plastic Deformation, and Highly Flexible Yb2O3 Nanofibrous Membranes for Thermal Insulation

“…Compared with some other porous thermal insulation materials, such as silane-modified mxene/polybenzazole nanocomposite aerogels, polydimethylsiloxane foam materials, and polysiloxane aerogel, YbFMs also exhibit good thermal insulation performance. As is well-known, the thermal conductivity of materials is influenced by three primary factors: (1) thermal convection, (2) thermal conduction of gas and solid, and (3) heat radiation. − Hence, the increase in the thermal conductivity of YbFMs at high temperatures can be attributed to the cumulative effects of these different heat transfer mechanisms. The internal structure of YbFMs is characterized by an interlaced distribution of nanofibers, hindering the fluid convection within it and thus reducing the impact of thermal convection.…”

Deciphering the synergistic action of multiple factors inducing high piezoresponse in CaBi4Ti4O15‐based piezoelectric ceramics

“…Various previous studies have focused on this method, and some achievements had been realized. 13,14 Wu et al 15 revealed that CBT ceramics doped with Bi 4 Ti 3 O 12 exhibit an optimal piezoelectric constant (d 33 = 13 pC/N). Liu et al 16 reported that Ta/Mn co-doped CBT ceramics exhibit improved electrical properties (d 33 = 24.0 pC/N, T c = 793 1 and Figure S1.…”