Effect of thermal-cycling on the piezoelectricity of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 Pb-free piezoceramic.

The reliability of piezoelectricity under thermal-cycling is an important consideration for the practical application of Pb-free piezoelectric materials. In this paper, we investigated the effect of thermal-cycling on the piezoelectricity of 0.5Ba(Zr 0.2 Ti 0.8)O 3 -0.5(Ba 0.7 Ca 0.3)TiO 3 (BZT-BCT) Pb-free piezoceramic. The results show that, in BZT-BCT, the tetragonal-orthorhombic (T-O) transition causes a strong piezoelectricity degradation (∼40% reduction after 60 thermal cycles between −40 °C and 50 °C), whereas the orthorhombic-rhombohedral (O-R) transition only leads to negligible degradation during the thermal-cycling test, indicating a weak depoling effect. The comparative studies made between BZT-BCT and BaTiO 3 (BT) reveal that the weak depoling effect results from the diffuseness of the O-R transition in BZT-BCT and weak domain pattern change across the transition. Our work implies that Pb-free piezoelectrics with good thermal-cycling stability can be achieved through engineering the normal ferroelectric-to-ferroelectric transition to a diffused one, which may help to design new Pb-free piezoelectric materials with good thermal-cycling stability. Image 1 • Normal ferroelectric-to-ferroelectric phase transition leads to a poor thermal-cycling stability. • Diffuse ferroelectric-to-ferroelectric phase transition causes a good thermal-cycling stability. • Good thermal-cycling stability roots in the weak domain pattern changes. [ABSTRACT FROM AUTHOR]