Structure and electrical properties of IrO2-doped 0.5Ba(0.7)Ca(0.3)TiO(3)-0.5BaTi(0.8)Zr(0.2)O(3) ceramics via low-temperature sintering

摘要

Lead-free ceramics 0.5Ba(0.7)Ca(0.3)TiO(3)-0.5BaTi(0.8)Zr(0.2)O(3)-xIrO(2) (x = 0-1.2 %) were prepared at a low temperature of 1260 A degrees C via sintering the as-synthesized nanoparticles, which were synthesized by a modified Pechini polymeric precursor method. All samples featured high levels of densification under the synthesis conditions; particularly, the ceramic prepared at IrO2 content of 0.4 % achieved the highest relative density (similar to 97.4 %). Phase transition from tetragonal to orthorhombic and a polymorphic phase transition (PPT) region were observed, which were influenced by the IrO2 content. The dielectric properties, temperature coefficient of capacitance, ferroelectric properties, and piezoelectric properties as a function of IrO2 content were thoroughly studied. Optimal electrical properties (remnant polarization, piezoelectric constant, and planar electromechanical coupling factors, i.e., P (r) = 6.28 mu C/cm(2), d (33) = 199 pC/N, and k (p) = 0.258) were obtained around the PPT region. The findings of the ceramic electrical properties by IrO2 doping are believed to be insightful in the development of lead-free dielectric and ferroelectric materials.