Search

Ultrahigh piezoelectric constant (d33 = 683 pC/N) and converse piezoelectric coefficient (dS/dE = 1257 pm/V) were observed in CuO-doped lead-free (Ba,Ca)(Ti,Sn)O3 ceramics at an optimal composition fabricated by a conventional sintering method at a low temperature 1250 °C. Since all samples showed a pure perovskite structure with coexisting multiphases including cubic, tetragonal, orthorhombic, and rhombohedral phases around two converged triple points, a good compositional stability of high piezoelectricity along with a high d33 and dS/dE over 600 pC/N and 1000 pm/V was achieved within a wide compositional region (1.0 ≤ x ≤ 3.0) regardless of the CuO content (x). [ABSTRACT FROM AUTHOR]

The phase structure in the (Ba,Ca)(Ti1-xSnx)O3 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 [variant_greek_epsilon]r and differential scanning calorimetry, an ultrahigh piezoelectric coefficient d33 = 670 pC/N and electrostrain 0.061% were achieved. The high d33 over 520 pC/N was stabilized in a wide compositional range of 0.07 ≤ x ≤ 0.11, suggesting that (Ba,Ca)(Ti,Sn)O3 ceramics are a promising candidate for the lead-free piezoelectric ceramics. [ABSTRACT FROM AUTHOR]