Enhanced piezoelectric properties and thermal stability in Mo/Cr co-doped CaBi2Nb2O9 high-temperature piezoelectric ceramics

Mo/Cr modified CaBi2Nb2-x(Mo2/3Cr1/3)(x)O-9 (x = 0.03, 0.04, 0.05, 0.06, 0.07, 0.075, and 0.1) were synthesized by the conventional solid-state reaction method. The effects of Mo/Cr substitution for Nb on structure, dielectric properties, piezoelectric properties and electrical conduction behaviours of CBN were investigated in detail. Results showed that moderate substitution of Nb with Mo/Cr optimized crystal structure and led to a reduction in oxygen vacancies, which effectively improved the electrical properties of the CBN ceramics. The CaBi2Nb1.93(Mo2/3Cr1/3)(0.07)O-9 ceramic showed optimal properties with a high d(33) of similar to 15 pC/N along with a high T-C of similar to 939 degrees C, an enhanced electrical resistivity (rho) of 3.33 x 10(5) Omega cm accompanied by a decreased dielectric loss of tan delta = 6.5% at 600 degrees C. Furthermore, the ceramic also exhibited a remarkable thermal stability performance that d(33) remained 93% of its original value when the annealing temperature rose up to 850 degrees C. All these properties demonstrated the great potentials of Mo/Cr doped CBN-based ceramic for high-temperature applications.