Optical and electrical properties of pressureless sintered transparent (K0.37Na0.63)NbO3-based ceramics

摘要

Lead-free (1-x)(K0.37N0.63)NbO3-xCa(Sc0.5Nb0.5)O-3 (x=0.050, 0.070, 0.090, 0.095 and 0.100) transparent ferroelectric ceramics have been fabricated by pressureless sintering procedure. Transmittance of 0.91(K0.37Na0.63)NbO3-0.09Ca(Sc0.5Nb0.5)O-3 ceramics sintered in sealed alumina crucible was 15% higher than those sintered unsealed in air. By increasing the content of Ca(Sc(0.5)Nba(5))O-3, the phase structure of (K0.37Na0.63)NbO3 ceramics transformed from orthorhombic to tetragonal symmetry first and then to pseudo cubic symmetry. The 0.91 (K0.37Na0.63)NbO3-0.09Ca(Sc0.5Nb0.5)O-3 ceramics exhibited high density (98%), high transmittance (60%) in the near-IR region and relatively good electrical properties (epsilon(r)=1914, tan delta=0.037, T-c=147 degrees C, P-r=6.88 mu C/cm(2), E-c = 8.49 kV/cm). Meanwhile, the introduction of Ca (Sc0.5Nb0.5)O-3 induced a composition fluctuation in the (K0.37Na0.63)NbO3 lattice and made the ceramics more relaxor-like, which would lead to a further reduction of light scattering. These results demonstrated that 0.91(K0.37Na0.63)NbO3-0.09Ca(Sc0.5Nb0.5)O-3 could be promising lead-free transparent ferroelectric ceramics. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.