The evolution of phase structure, dielectric, strain, and energy storage density of complex-ions (Sr1/3Nb2/3)(4+) doped 0.82Bi(0.5)Na(0.5)TiO(3)-0.18Bi(0.5)K(0.5)TiO(3) ceramics

摘要

Lead-free Bi-0.5(Na0.82K0.18)(0.5)Ti1-x(Sr1/3Nb2/3)(x)O-3 (abbreviated as BNKT-xSN, x = 0.02-0.045) ceramics were fabricated via the conventional ceramic process, and the (Sr1/3Nb2/3)(4+) complex-ions were used to modify the phase transition and multifarious electrical responses of BNKT-xSN ceramics. The SN complex-ions absolutely incorporate into the lattice of BNKT matrix to form perovskite structure. The grain morphologies and size are almost unaffected by SN complex-ions. The phase transition concerning ferroelectric type transforming into ergodic relaxor happens with increasing SN content, and the corresponding critical point is x = 0.035. The phase transformation process results in the improvement of energy storage density (W = 0.754 J/cm(3)) at 80 kV/cm and a high bipolar strain (S = 0.25%) with small hysteresis. The dielectric constant at T-m peaks gradually decreases with increasing SN content, and the ferroelectric-relaxor transition temperature (TF-R) is depressed to room temperature. The evolution behaviors might facilitate our cognition about the mechanism between phase structure and multiple electrical properties of BNT-based ceramics.