Microstructure and electrical properties in W/Nb co-doped Aurivillius phase Bi4Ti3O12 piezoelectric ceramics

• W/Nb codoped BIT ceramics were prepared by the mixed oxides route.
• High nd0 electronic configuration of W/Nb reduces the lattice distortion and T­C.
• Oxygen vacancy is responsible for dielectric relaxation and DC conduction process.
• W/Nb additives significantly enhanced the piezoelectric coefficient d33 value.
• BWNb-10 ceramics possessed large remnant polarization and a wide sintering window.

Aurivillius-type Bi4Ti3-xWx/2Nbx/2O12 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 Bi4Ti2.9W0.05Nb0.05O12 ceramics exhibited optimum piezoelectric coefficient (d33 ∼22.8 pC/N), large remnant polarization (2Pr ∼26.8 μC/cm2 @ 200 °C) together with a high Curie temperature (TC ∼635 °C). Furthermore, this composition possessed a wide sintering window with outstanding piezoelectric properties. These parameters indicate that Bi4Ti2.9W0.05Nb0.05O12-based ceramic is a promising candidate for high temperature piezoelectric applications.

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