LOW-FREQUENCY PIEZOELECTRIC CERAMIC MATERIAL BASED ON BISMUTH FERRITE AND LEAD FERRONIOBATE Russian patent published in 2025 - IPC C04B35/497 C04B35/26 

FIELD: chemistry.

SUBSTANCE: invention relates to piezoelectric ceramic materials based on bismuth ferrite and lead ferroniobate and can be used to create electromechanical transducers in ultrasonic flaw detection, operating in the frequency range of 24.0-28.0 kHz. Piezoceramic material with chemical formula (1-x)BiFeO₃–xPb(Fe_0.5Nb_0.5)O₃, where x = 0.95, contains over stoichiometry germanium oxide GeO₂ with following ratio of initial components, wt. %: Bi₂O₃ 5.21-5.22; Fe₂O₃ 18.77-18.79; PbO 47.47-47.51; Nb₂O₅ 28.27-28.29; GeO₂ 0.28-0.19. Introduction of glass-forming additive of germanium oxide into solid solutions of binary system (1-x)BiFeO₃–xPb(Fe_0.5Nb_0.5)O₃ leads to formation of a single-phase state with cubic symmetry without impurity phases.

EFFECT: increased anisotropy of piezomodules d₃₃/|d₃₁| to values of 7-8, anisotropy of electromechanical coupling coefficients K_t/K_p to values close to 10, reduction of mechanical quality factor Q_M to values of 100-150, reduction of temperature of the first synthesis and sintering temperature while maintaining high values of relative permittivity of polarized samples, ε^T₃₃/ε₀, equal to 5700-6600.

1 cl, 8 dwg, 4 tbl