Microstructure and electrical properties in W/Nb co-doped Aurivillius phase Bi_4Ti_3O_(12) piezoelectric ceramics

摘要

Aurivillius-type Bi_4Ti_(3-x)W_(x/2)Nb_(x/2)O_(12) ceramics were prepared by a conventional solid-state sintering method. The XRD patterns demonstrated that all compositions were a single three layered crystalline structure, involving a reduction of lattice distortion with an increase in W/Nb doping level. The electrical properties including dielectric, electrical conduction and piezoelectric properties were tailored by W/Nb additives. The Curie-temperature decreased, whereas the electrical resistivity drastically increased with introduction of W/Nb donor dopants. As a result, a high electric field can be applied during the poling process. The Bi_4Ti_(2.9)W_(0.05)Nb_(0.05)O_(12) ceramics exhibited optimum piezoelectric coefficient (d_(33) ～22.8pC/N), large remnant polarization (2P_r ～26.8 μC/cm~2@200℃) together with a high Curie temperature (T_C ～635 ℃). Furthermore, this composition possessed a wide sintering window with outstanding piezoelectric properties. These parameters indicate that Bi_4Ti_(2.9)W_(0.05)Nb_(0.05)O_(12)-based ceramic is a promising candidate for high temperature piezoelectric applications.