Structure–microstructure–property relationships in lead-free BCTZ piezoceramics processed by conventional sintering and spark plasma sintering

Abstract

a b s t r a c tLead-free piezoelectric ceramics belonging to the pseudo-binary system (1 − x)BaTi 0.8 Zr 0.2 O 3 -x Ba 0.7 Ca 0.3 TiO 3 (BCTZ, x = 0.32 and 0.5) were prepared using conventional sintering and spark plasma sintering. This comparative study shows how the macroscopic properties of ferroelectric BCTZ perovskites are affected when the grain size is decreased. The crystallographic structure and the microstructural characteristics are thoroughly investigated for ceramic samples obtained by both sintering methods. We clearly demonstrate that the dielectric, piezoelectric, pyroelectric and ferroelectric properties in SPS ceramics are strongly affected by the grain size and the structural defects leading to local strain fields which undermine the polarisation flexibility. This confirms that the critical compositions showing remarkably large piezoelectric coefficients are extremely sensitive to external and internal stresses.

Enhanced ferroelectric properties and thermal stability of Mn‐doped 0.96(Bi0.5 Na0.5)TiO3‐0.04BiAlO3 ceramics

“…The P r increases as Mn addition increases up to 0.7 mol% with a remarkably high value approximately 41 μC/cm 2 . Similar relationship between P r and grain size was also observed in other studies . It was suggested that single domain state tended to transform into multidomain structure with the increase in grain size .…”

“…Similar relationship between P r and grain size was also observed in other studies. 22,23 It was suggested that single domain state tended to transform into multidomain structure with the increase in grain size. 24 In this case, both domain wall motion and domain switching become feasible due to the reduced clamping effect of the neighboring grains and the existence of domain walls.…”

Towards Lead-Free Piezoceramics: Facing a Synthesis Challenge

“…Therefore, strategies to reduce the synthesis and sintering temperatures are needed for processing routes towards sub-10 µm grain size ceramics. Most of the work has been carried out following the solid state synthesis route, and the role of dopants and substitutions [14,15,61,62,63], the processing related ceramic microstructure [64,65,66,67], resulting in strong changes in the piezoelectric coefficient for the same composition (Figure 6), and the poling process [68] have been the current topics of this research line.…”

On the origin of grain size effects in Ba(Ti0.96Sn0.04)O3 perovskite ceramics

“…The study of grain size effects in polycrystalline ferroelectrics has drawn great interest in the past decades and it still represents a hot topic in the area of ferroelectrics [1][2][3][4][5][6][7][8][9][10][11]. The majority of studies on grain size effects currently available in the literature are mainly focused on two aspects.…”