Structural And Dielectric Properties In (1-X)Batio_3-Xbi(Mg_(1/2)Ti_(1/2))O_3 Ceramics (0.1 ≤ X ≤ 0.5) And Potential For High-Voltage Multilayer Capacitors

摘要

Structural and dielectric properties of (1-x)BaTiO_3-xBi (Mg_(1/2)Ti_(1/2))O_3 (x = 0.1-0.5) were investigated to understand the binary system and utilize it for high-voltage, high energy density capacitors. The solubility limit for Bi(Mg_(1/2)Ti_(1/2)O3 in a BaTiO_3 perovskite was between x = 0.4 and x = 0.5. A phase with pseudocubic symmetry was formed for x = 0.1-0.4; a secondary phase developed at x = 0.5. Dielectric measurements showed highly diffusive and dispersive relaxor-like characteristics from 10 to 40 mol% of Bi(Mg_(1/2)Ti_(1/2))O_3. These compositions also showed high relative permittivity with low-temperature coefficients of permittivity over a wide range of temperatures -100℃-600℃. Relaxation behavior was quantitatively investigated using the Vogel-Fulcher model, which revealed the activation energy of 0.17-0.22 ev. Prototyped multilayer capacitors of 18 mm x 17 mm x 4 mm dimensions with a capacitance of 12.5 nf at 1 khz were successfully constructed and demonstrated multiple charge-discharge characteristics up to 10 kv.