Rapid pressure-less and spark plasma sintering of (Ba0.85Ca0.15Zr0.1T0.9)O-3 lead-free piezoelectric ceramics

摘要

This work shows for the first time the possibility to sinter BCZT powder compacts by rapid heating rates within one hour of sintering, while achieving good piezoelectric properties. The sintering was performed by rapid (heating rates 100 and 200 degrees C/min) pressure-less sintering (PLS) at 1550 degrees C/5-60 min and by SPS sintering (100 degrees C/min, 1450 degrees C/5 60 min and 1500 degrees C/15 45 min). The rapid PLS samples reached a relative density up to 94 % and grain sizes of 17-36 mu m acquiring d(33) up to 414 pC/N. Although the SPS samples reached full density at 1450 degrees C, their piezoelectric properties worsened due to smaller grains (10-15 mu m) as well as formation of cracks at dwell times > 30 min. At elevated SPS temperature of 1500 degrees C/30 min, the d(33) increased to 360 pC/N sustaining full density. Even higher increase in d(33) (424 pC/N) of SPS samples was achieved by post-rapid PLS at 1550 degrees C/60 min resulting from further expansion in grain size.