Electrical properties and tracer diffusion of oxygen in some Bi-based lead-free piezoelectric ceramics

The relationship between electrical properties and oxygen tracer diffusion was focused for Bi based piezoelectric ceramics including typical perovskite ferroelectrics, (Bi1/2Na1/2)TiO3 (BNT), and Bi layer-structured ferroelectrics, Bi4Ti3O12 (BIT). The oxygen tracer diffusion was investigated by secondary ion mass spectrometry, SIMS. Volume diffusion coefficients, Dv, of 18O in Bi excess BNT (BNT+Bi2O3 0.3 mass%, BNT-0.3) and V-substituted BIT (Bi4Ti3-xVxO12, BITV-x) ceramics were dramatically decreased as compared with those in non-doped ceramics. These results suggest that the concentration of oxygen vacancies decreased. On the other hand, electromechanical coupling factor, k33, for BNT-0.3 and BITV-0.02 ceramics are 0.47 and 0.25, respectively, which are the largest in each system.