Na 0.5 Bi 2.5 Nb 2 O 9 lead-free piezoelectric ceramics with high Curie temperature derived from sol–gel route

Abstract

An Aurivillius phase bismuth layer-structured compound, Na_0.5Bi_2.5Nb₂O₉ (NBN), has been prepared by an economical aqueous sol–gel technique. The results indicated that pure NBN nano-particles can be obtained at a low temperature of 650°C and the morphology are platelike with grain sizes of about 40 nm. Using these nano-particles, the dense NBN ceramics were fabricated at 1100°C for 2 h. The Curie temperature T_c and piezoelectric coefficient d₃₃ at room temperature for the present ceramic were found to be 770°C and 11 pC/N, respectively. Thermal annealing studies indicate that the NBN ceramic possesses stable piezoelectric properties, demonstrating it is a promising candidate for high-temperature applications.