Phase transition and high piezoelectricity in (Ba,Ca)(Ti1-xSnx)O3 lead-free ceramics

The phase structure in the (Ba,Ca)(Ti1-xSnx)O-3 lead-free ceramics was evolved from inceptive orthorhombic (O) at 0 <= x <= 0.04 to a two-phase coexistence of pseudocubic-orthorhombic (PC-O) at 0.06 <= x <= 0.10 and further to a multiphase coexistence of rhombohedral-pseudocubic-orthorhombic (R-PC-O) at x = 0.11. Due to the multiphase coexistence of R-PC-O at room temperature proved by X-ray diffraction, dielectric constant er and differential scanning calorimetry, an ultrahigh piezoelectric coefficient d(33) = 670 pC/N and electrostrain 0.061% were achieved. The high d(33) over 520 pC/N was stabilized in a wide compositional range of 0.07 <= x <= 0.11, suggesting that (Ba,Ca)(Ti,Sn)O-3 ceramics are a promising candidate for the lead-free piezoelectric ceramics. (C) 2013 AIP Publishing LLC.