Phase Evolution, Microstructure and Electrical Behavior of (Ba0.97Ca0.03)(Ti0.94-x/2Sn0.06-x/2Wx)O3 Ceramics Synthesized via the Solid-State Combustion Technique

Abstract

This research studied the effect of W4+ substitution on the phase formation, microstructure and electrical properties of (Ba0.97Ca0.03)(Ti0.94-x/2Sn0.06-x/2Wx)O3 (BCTSW) ceramics with x = 0, 0.005, 0.010, 0.015 and 0.020 mol%. The BCTSW ceramics were synthesized by the solid-state combustion technique, using glycine as fuel. The powders and green pellets of BCTWS were calcined and sintered at 1100 °C for 4 h and 1400 °C for 2 h, respectively. A pure perovskite phase with coexisting orthorhombic and tetragonal phases were observed for all samples. The content of the tetragonal phase increased when x rose, as verified by the Rietveld refinement procedure. The average grain size and the measured density of the samples tended to decrease from 35 ± 0.56 to 1.9 ± 0.12 µm and 5.59 to 4.88 g/cm3, respectively, when x increased. The dielectric behavior of the ceramics strongly degenerated upon W4+ substitution. The undoped BCTS ceramic showed a well-saturated P-E hysteresis loop. With W4+ substitution, the samples’ P-E loops became unsaturated and a leakage current was created.