Phase Structure And Property Enhancement Of High-Performance BaTiO₃-based Lead-Free Piezoelectric Ceramics

BaTiO3ceramics are one kind of important functional materials. In recent years, since piezoelectric properties have made a significant breakthrough, BaTiO3-based lead-free piezoelectric received great attention. However, up until this point, there was little research done surrounding high-performance BaTiO3system. It is possible to broaden high-performance components area and obtain multiple high-performance BaTiO3-based lead-free piezoelectric ceramics through optimizing the element types and contents of dopants. In this paper, the high-performance BaTiO3lead-free piezoelectric ceramics were prepared by optimizing components and controlling phase structure. The relation between content of the different elements and phase structure was meticulously researched and the effect mechanism of high d33also was revealed.The effects of phase structure and electric properties in (Ba,Ca)TiO3-0.04LiF system with different Ca contents was researched. As increasing Ca content, the phase structure of sample turns into pseudo-cubic (PC) one from orthorhombic (O) phase. The sample achieved excellent electric properties, such as d33=361pC/N and=0.412, because of O-PC two-phase coexistence as Ca content is0.02.The impact of phase structure and electric properties with different element contents was systematically researched in (Ba,Ca)(Ti,Sn)O3lead-free piezoelectric ceramics. The ingredient region of two-or multi-phase coexistence along with their impacts on the piezoelectric, ferroelectric and dielectric performaces as well as electrostrain were illuminated via adjusting the relative proportion of each element and controlling phase structures of the samples. The ultrahigh piezoelectric coefficient d33=670pC/N and d33≥500pC/N were achieved at x=0.11and width of the component area at0.07≤x≤20.11in (Ba0.95Ca0.o5)(Ti1-xSnx)03system, respectively. In addition, the ultrahigh strain0.07and inverse piezoelectric coefficient d33*=1444pm/V were achieved in BaTiO3-x(0.4CaTiO3-0.6BaSnO3) system at x=0.16. These results suggest that (Ba,Ca)(TiSn)O3ceramic is a promising lead-free piezoelectric material.Phase structure and electrical performance of (0.7-x)BiFeO3-0.3BaTiO3-xBi(Mgi/2Ti1/2)03system with high curie temperature were studied along with the emphasis on the Bi(Mg1/2Ti1/2)O3content. The samples with R-PC two-phase coexistence were prepared via adjusting the relative proportion of each elemant and controlling the phase structure, which effectively enhances the piezoelectric property. The high d33=154pC/N and TC=482℃were achieved at x=0.04because. of R-PC two-phase coexistence. This result suggests that BiFeO3-BaTiO3-Bi(Mg1/2Ti1/2)O3ceramics have good prospects in the high-temperature piezoelectric devices.