Structure and electrical properties of lead-free (1 − x)(K0.45Na0.5Li0.05)Nb0.95Sb0.05O3 − x(Ca0.95Ba0.05)(Zr0.9Sn0.1)O3 ceramics

Lead-free perovskite piezoelectric (1 − x)(K0.45Na0.5Li0.05)Nb0.95Sb0.05O3 – x(Ca0.95Ba0.05)(Zr0.9Sn0.1)O3 ceramics were fabricated via a conventional sintering process. A microstructural study was conducted for the ceramics through a scanning electron microscope, whose grain sizes were found to gradually reduce with increasing x. The phase structure of the studied ceramics was identified by the combined analysis of X-ray diffraction data and dielectric-temperature measurements, and a rhombohedral–orthorhombic–tetragonal phase coexistence was observed to exist in the wide composition range of 0 ≤ x ≤ 0.05. The ceramics exhibited the optimal piezoelectric properties at x = 0.01, which had a piezoelectric constant d33 of 290 pC/N and a planar electromechanical coupling coefficient of 0.43. A diffuse phase transition was induced with x increased to a relatively high value, featuring the broadening of Curie peak. In addition, the variations of ferroelectric properties with composition were investigated in this work as well. The authors believe that adding the calcium barium zirconate stannate compound (Ca0.95Ba0.05)(Zr0.9Sn0.1)O3 into (K,Na)NbO3-based ceramics is a valid way for the improvement of their piezoelectric properties.