Lead-free piezoelectric ceramics of Ba0.70Ca 0.30Ti1-xFexO3 (x=0-0.03) have been synthesized by a conventional solid state reaction method. The influence of Fe content on the microstructure, phase transition, dielectric, ferroelectric, and piezoelectric properties is investigated systematically. The ceramics with x≤0.02 are diphasic composites of tetragonal Ba0.80Ca 0.20TiO3:Fe and orthorhombic Ba0.07Ca 0.93TiO3:Fe solid solutions. The tetragonal phase is gradually suppressed as x increases, the ceramic with x=0.03 is found to have diphasic pseudocubic and orthorhombic phases. And the grain size is dependent on Fe content significantly. Introduction of Fe at B-sites improves the densification and decreases the sintering temperature. As x increases from 0 to 0.03, the room temperature relative dielectric permittivity enhances, dielectric loss decreases, and the Curie temperature decreases monotonically from 128 C to 58 C. However, the ferroelectricity enhances slightly and reaches the maximum near x=0.005, and then weakens with increasing x. On the other hand, the piezoelectric coefficient (d33) and the electromechanical coupling coefficient (kp) decrease simultaneously with increasing x, whereas the mechanical quality factor (Qm) increases significantly. The structure-electrical properties relationship is discussed intensively to give more information on (Ba,Ca)TiO3-based lead-free piezoelectric ceramics.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry