Synthesis of KNbO3 Piezoelectric Ceramics Using Citrate Precursors

概要

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An aqueous-based citrate precursor route has been adopted for the synthesis of KNbO3 nanopowders. The required amount of KNO3 or C6H5O7K3$\cdot$H2O solution was mixed with citric Nb solution to form white precipitates, followed by heat treatment at 800 °C to produce KNbO3 nanopowders with an average particle size of 250–300 nm. The as-received nanopowder showed a well-sinterable property without using any additives, and the obtained KNbO3 ceramics showed saturated ferroelectric hysteresis loops of $P_{\text{r}} = 22.9$ μC/cm2 and $E_{\text{c}} = 7.8$ kV/cm at 1 Hz. The excellent piezoelectric properties of $k_{\text{p}} = 0.35$, $Q_{\text{m}} = 131$, $k_{31} = 0.23$, $d_{31} = -31$ pC/N, and $d_{33} = 110$ pC/N were obtained for KNbO3 ceramics derived from KNO3 solution, whereas $k_{\text{p}} = 0.29$, $Q_{\text{m}} = 96$, $k_{31} = 0.20$, $d_{31} = -45$ pC/N, and $d_{33} = 115$ pC/N were obtained for KNbO3 ceramics derived from C6H5O7K3$\cdot$H2O solution.
2008-09-25