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Ca0.6(Li0.5Bi0.5‐xPrx)0.4Bi2Nb2O9 ceramics were prepared via a solid‐state reaction method. The effect of the Pr content on the structural and electrical properties was systematically investigated. X‐ray diffraction (XRD) combined with Rietveld refinement and X‐ray photoelectron spectroscopy (XPS) demonstrated that a moderate amount of Pr3+ can be incorporated into the NbO6 octahedra, while excess Pr3+ ions probably enter into the (Bi2O2)2+ layers, thus resulting in an increase in the tetragonality of the crystal structure. The introduction of Pr suppressed the generation of oxygen vacancies and improved the preferential grain growth along the c‐axis, which might be responsible for enhancing the resistivity (ρ ~ 106 Ω cm at 600°C). The replacement of Pr3+ for A‐site Bi3+ enhanced the piezoelectric property, and the piezoelectric constant d33 increased from 13.8 pC/N to 16.3 pC/N. The high depolarization temperature (up to 900°C) implied that CBN‐LBP100x ceramics are promising candidates for ultrahigh‐temperature application.

Bi 4 Ti 3 O 12 high-temperature piezoelectric ceramics composed of 0.03 mol (Nb, Ta) 5+ substituting B site and x mol CeO 2 (x = 0-0.05, abbreviated as BCTNT100x) substituting A site were synthesized by the conventional solid-state reaction method. The effects of Ce additive on the structures and electrical properties of resulting Bi 4 Ti 3 O 12 -based ceramics were systematically investigated. In-situ temperature-dependent X-ray diffraction (XRD) confirmed that the phase structure of BCTNT100x ceramics change from orthorhombic structure to tetragonal structure as temperature increased. The ceramics at Ce content x = 0.03 illustrated optimal performances with superior piezoelectric constant (d 33 = 36.5 pC/N), high Curie temperature (T C = 649 • C), and large remanent polarization (2P r = 21.6 μC/cm 2 ). BCTNT3 ceramics also possessed high d 33 of 32.5 pC/N at an annealing temperature of 600 • C, with electrical resistivity preserved at 10 6 Ω cm at 500 • C. These results demonstrate that BCTNT100x ceramics can be used as high-temperature piezoelectric devices.

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The molten-salt method was used to synthesize CaBi 2 Ta 2 O 9 (CBTa) powder, and the influence of temperature on the structure and micromorphology of products was investigated using X-ray diffraction and the scanning and transmission electron microscope. The results showed that highly crystalline CBTa nanoplates exhibit single orthorhombic symmetry and could be obtained in the temperature range of 850-900°C. Among which, the nanoplates prepared at 900°C have optimal properties (average grain size of 1.7 μm and uniform size distribution). Above 900°C, various CaO-Ta 2 O 5 binary compounds, Bi 2 O 3, and BiTaO 4 formed due to the decomposition of CBTa and subsequent reactions of decomposition products, transforming plate-like grains to cuboid nano-particles with a small amount of prismatic grains. Possible reaction mechanisms at different synthesizing temperature were proposed. This work provides a method for the preparation of template grains to synthesize textured CaBi 2 Ta 2 O 9 high-temperature piezoelectric ceramics by the template grain growth method.

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