Dense KSr2Nb5O15 ceramics with uniform grain size prepared by molten salt synthesis

Dense KSr2Nb5O15 (KSN) ceramics with various grain-size distributions were prepared by the conventional solid-state sintering under different conditions, e.g. one-step and two-step techniques. Bi2O3 (2 mol%) was added as sintering aid. KSN powder crystals prepared by the molten salt synthesis was used as raw materials. Varying temperature from 1250 °C to 1350 °C at one-step sintering technique were found to enhance abnormal grain growth. For two-step sintering technique, presintering at 1250 °C followed by higher sintering temperature of 1350 °C controlled abnormal grain growth and obtained a dense KSN ceramics with uniform grain size (an average grain size of 3 μm). The effect of KSN powder crystals on promoting densification and presintering technology on controlling abnormal grain growth were discussed. The correlation of microstructure with dielectric properties was investigated.