Abstract
The functional properties of BaTiO3 ceramics,produced by using the same pressing/sintering strategy from nanopowders with two distinct morphologies(cuboidal/equiaxed nanoparticles)and similar parti-cle sizes,are comparatively investigated.The sintered ceramics exhibit similar nanoscale structures,with faceted crystalline grains and crystalline inclusions,clean grain boundaries and well-defined 90° lamellar domains extending in some entire grains or finer nanodomains inside grain regions.The differences in the functional behavior originating from the different nanopowder morphology are described in terms of the nanoparticle assembly during the pressing step.The numerically simulated green body densification indicated a more efficient assembly resulting in higher density for the cubic particles(0.90 vs.0.84 rel-ative density)and a more homogeneous pore distribution in the spherical-derived ones.As a result of the higher density after sintering,the functional properties are enhanced in cuboid-originated ceramics.For comparison,the ceramic produced from cubic nanoparticles sintered at T1/T2=1250/800 ℃ shows higher permittivity(room temperature value of～2100-cubic vs.～1700-rounded),enhanced ferroelec-tric characteristics(cubic:Ps=8.57 μC cm-2,Pr=0.95 μC cm-2,and Ec=2.3 kV cm-1,with respect to Ps=6.06 μC cm-2,Pr=0.4 μC cm-2,and Ec=1.4 kV cm-1,for spherical-derived ones,measured at Emax=29.3 kV cm-1)and a stronger dc-field dependence of their permittivity of～12％(cubic)vs.only～2％(spherical),for a dc-applied field in the range of-15 kV cm-1＜Edc＜15 kV cm-1.In contrast,the spherical particles-derived ceramics contain fewer defects and have a more homogeneous and finer porosity distribution in the ceramic volume and consequently,they are more stable and sustain larger field applications in comparison with the cubic-derived counterparts.
基金项目
Romanian Ministry of Education and Research,CNCS-UEFISCDI(PN-Ⅲ-P1-1.1-PD-2021-0531)
NETL
NSTL
万方数据