Abstract
This research studied the effect of MnO2 substitution on the phase formation, microstructure and electrical properties of (Ba0.97Ca0.03)(Ti0.94-xMnxSn0.06)O3 (BCTMS with x = 0, 0.005, 0.010, 0.015, and 0.020 mol%) lead-free piezoelectric ceramics. The BCTMS ceramics were fabricated by the solid-state combustion technique. The powders and green pellets were calcined and sintered at 1100 °C for 4 h and 1400 °C for 2 h, respectively. The XRD patterns of all BCTMS ceramics exhibited a single perovskite structure with the coexisting orthorhombic and tetragonal phases, where the tetragonal phase increased and the orthorhombic decreases with increasing x. The average grain size decreased from 35 to 13 µm with increasing x. The dielectric constants at room temperature (εr) and at the Curie temperature (εC), density, remanent polarization (Pr), and piezoelectric coefficient (d33) decreased as x increased. The changes in the crystal structure and microstructure affected electrical properties.
Acknowledgments
The authors wish to thank the Department of Physics, Faculty of Science, Naresuan University for their supporting facilities. Thanks are also given to Asst. Prof. Dr. Kyle V. Lopin for his help in editing the manuscript.