Rapid pressureless sintering of barium titanate-based piezoceramics and their electromechanical harvesting performance

The innovative method of processing of Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT), Ba0.95Ca0.05Ti0.91Sn0.09O3 (BCST), and BCZT doped with 0.07-wt.% CeO2 (Ce-BCZT) lead-free piezoceramics is presented. The rapid pressureless sintering (RPLS) technique can reduce high-temperature processing time more than eight times compared to the conventional sintering. RPLS was performed at a heating and cooling rate of 100 degrees C/min up to 1550 degrees C with 15-, 30-, 45-, and 60-min dwell times, producing defect and crack-free nearly dense ceramics. The optimal microstructure exhibiting the highest piezoelectric constant was reached after 30 min in BCZT (grain size 25-30 mu m, d(33) = 428 pC/N), 45 min in Ce-BCZT (grain size 30-35 mu m, d(33) = 515 pC/N), and 45 min of dwell time in BCST (grain size 58-68 mu m, d(33) = 443 pC/N). The highly competitive energy-harvesting properties were discovered for BCZT, resp. Ce-BCZT (n = 94.5, resp. 93.4%, FOMoff = 6.1, resp. 7.8 x 10(-10) m(2)/N) ceramics.