Improvement of piezoelectric properties of Bi4Ti3O12 ceramics by Mn/Ta co-doping and direct reaction sintering

Bi 4 Ti 3- x (Mn 1/3 Ta 2/3 ) x O 12 piezoelectric ceramics were prepared by conventional sintering and direct-reaction sintering in this study. The effect of B-site Mn/Ta co-substitution and sintering method on the microstructure and electrical properties of Bi 4 Ti 3- x (Mn 1/3 Ta 2/3 ) x O 12 piezoelectric ceramics was systematically investigated. The experimental results show that the combination of high-valent Ta and low-valent Mn ions replacing Ti 4+ ions reduce the concentration of oxide vacancy defects in BITMT ceramics. The direct-reaction sintering is a simpler preparation method and the prepared samples have more uniform grain distribution and higher density. The resistivity of the direct reaction sintered sample with x  = 0.05 at 500 °C is 7.19 × 10 5 Ωcm, the residual polarization is 8.1 μC/cm 2 , and the temperature stability of the piezoelectric constant is good. Therefore, the present study suggests that the piezoelectric properties of Mn and Ta co-doping of BIT ceramics could be greatly enhanced via the direct-reaction sintering, which provides a promising alternative to the conventionally sintered for a more cost-effective preparation for BIT ceramics.