Phase structure and electrical properties of (Ba1/2Sr1/2)²⁺ modified high Curie temperature CaBi₂Nb₂O₉‐based ceramics

High‐temperature piezoelectric sensing is usually used in the aerospace, automotive, and power plant fields. High temperature piezoelectric ceramics are considered the key materials in these fields. In this paper, Ca 1− x (Ba 1/2 Sr 1/2 ) x Bi 2 Nb 1.985 (W 3/4 Mn 1/4 ) 0.015 O 9 ( x = 0.05, 0.10, 0.15 and 0.20) (C 1− x BS x BNWM) has been synthesized by a traditional solid state reaction method. The effects of substitution of calcium at the A‐site by barium and strontium on phase evolution and piezoelectric properties of the CaBi 2 Nb 2 O 9 orthorhombic Aurivillius phases were investigated. The crystal structure of piezoelectric ceramics was characterized by XRD, Rietveld refinement, and Raman spectroscopy. Co‐substitution of barium/strontium (Ba 2+ /Sr 2+ ) and tungsten/manganese (W 6+ /Mn 4+ ) resulted in lattice distortion of C 1− x BS x BNWM ceramics. The results induce that the tetragonal crystal structure increase with increasing the co‐substitution cations. Isothermal impedance spectroscopy confirmed intrinsic thermally activated conduction in the system. The C 1− x BS x BNWM ceramics with x = 0.15 exhibit a very high Curie temperature ( T C ∼ 923°C), a reasonable piezoelectric coefficient ( d 33 = 13.3 pC/N). Remarkably, even after thermal annealing at temperatures up to 800°C, it still retains a high d 33 of 13 pC/N. In addition, the C 0.85 BS 0.15 BNWM ceramic had a relatively high resistivity (3.82 × 10 6 Ω·cm, 500°C). The Ca 0.85 (Ba 1/2 Sr 1/2 ) 0.15 Bi 2 Nb 1.985 (W 3/4 Mn 1/4 ) 0.015 O 9 ceramics make possible their application in high‐temperature acceleration transducers.