Synthesis and Electrical Properties of KF-Doped BaTiO3 Ceramics

概要

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KF-doped barium titanate ceramics, Ba1-xKxTiO3-xFx (KF-BT/$x$: $0\leqq x\leqq 0.15$), were fabricated by spark plasma sintering (SPS) using fine particles prepared by a sol–gel method. We measured the dielectric and piezoelectric properties of the SPS ceramics after annealing in an O2 gas flow at 1273 K. The dielectric constant and the piezoelectric constant $d_{33}$ were enhanced in KF-BT/0.10, as found in the single crystals, because the composition of $x=0.10$ locates near the tricritical point (TCP). However, some different behaviors from those of the single crystals were found; in particular, $T_{\text{C}}$ of the ceramic forms is much higher than that of the crystalline forms, and the difference becomes marked with increasing $x$. We consider that the evaporation of F-, which occurs during the O2 annealing process, markedly increases $T_{\text{C}}$.
2010-09-25