Structural, dielectric and piezoelectric study of Ca-, Zr-modified BaTiO$_3$ lead-free ceramics

Bulletin of Materials Science

关键词: BCTZ;    sintering;    grain size;    dielectric properties;    piezoelectric properties.;   

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

We prepared a lead-free ceramic (Ba$_{0.85}$Ca$_{0.15}$)(Ti$_{1−x}$Zr$_x$ )O$_3$ (BCTZ) using the conventional mixed oxide technique. The samples were prepared by an ordinary mixing and sintering technique. In this study we investigated howsmall amounts of Zr$^{4+}$ can affect the crystal structure and microstructure as well as dielectric and piezoelectric propertiesof BaTiO$_3$. X-ray diffraction analysis results indicate that no secondary phase is formed in any of the BCTZ powders for$0 \leq x \leq 0.1$, suggesting that Zr$^{4+}$ diffuses into BaTiO$_3$ lattices to form a solid solution. Scanning electron microscopy micrographs revealed that the average grain size gradually increased with Zr$^{4+}$ content from 9.5 $\mu$m for $x = 0.02$ to 13.5 $\mu$m for $x = 0.1$; Curie temperature decreased due to the small tetragonality caused by Zr$^{4+}$addition. Owing to the polymorphic phase transition from orthorhombic to tetragonal phase around room temperature, it was found that the composition $x = 0.09$ showed improved electrical properties and reached preferred values of $d_{33} = 148$ pC N$^{−1}$ and $K_p = 27$%.

【 授权许可】

CC BY