Doping level effects in Nb self‐doped Bi 3 TiNbO 9 high‐temperature piezoceramics with improved electrical properties

Abstract Nb self‐doped Bi 3 Ti 1‐ x Nb 1+ x O 9 ( x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1) high‐temperature piezoelectric ceramics were fabricated through the conventional solid‐state sintering method. The effects of different Nb self‐doping levels on the microstructure, piezoelectric activities, and electrical conduction behaviors of these Nb self‐doped Bi 3 Ti 1‐ x Nb 1+ x O 9 ceramics were studied in detail. Large doping level effects on piezoelectric activity and resistivity were confirmed, which might be ascribed to the evolution of the crystal structure and the variations of the oxygen vacancy concentration and the grain anisotropy induced by Nb doping. An optimized piezoelectric coefficient ( d 33 ) of 11.6 pC/N was achieved at x = 0.04 with a Curie temperature of 906°C. Additionally, an improved DC resistivity of 6.18 × 10 5 Ω·cm at 600°C was acquired in this ceramic. Furthermore, the ceramic exhibited excellent thermal stability with the d 33 value maintaining 95% of its initial value after being annealed at 850°C for 2 hours. These results showed that Nb self‐doped Bi 3 Ti 1‐ x Nb 1+ x O 9 ceramics might have great potentials for high‐temperature piezoelectric applications.