Besides the composition and grain size, the functional properties of electroceramics are strongly dependent on their porosity level, as well as on the microstructural characteristics of the existing pores (size, shape, orientation, distribution and phase interconnectivity). Specific porosity distribution and anisotropy [1] may determine peculiar strain-stress distributions, thus providing superior piezo/ferro/pyroelectric properties. In the present paper, the functional properties of porous BaTiO3 ceramics with pore anisotropy are numerically estimated by using Finite Element Models [2]. Ceramics with variable porosity levels and pore anisotropy have been produced by using polymer spheres as sacrificial templates. The real 3D ceramic microstructures have been determined by using X-Ray tomography (XCT) technique [2,3]. The 3D microstructures have been used as input in order to determine the local potential and electric field and the strain-stress fields inside the ceramic body. With respect to the SEM microstructures, the advantage of XCT method is to provide 3D real ceramic microstructures. Therefore, peculiar features as structural defects, cracks, percolated pores, anisotropy can be locally examined and their role on the material property peculiarities and failure can be better understood. Further, by using models for the dense ceramic component, the dielectric, ferroelectric and piezoelectric properties are estimated and then compared to the experimentally determined ones. The employed approach provides a bridge from meso- to macroscale in understanding the relationship between the microstructural characteristics and macroscopic material properties.
 
Acknowledgements: This work was supported by the Romanian UEFISCDI PN-III-P4-ID-PCE-2020-1988 grant.
 
References
[1] R.S. Stirbu et al., Materials 15, 6839 (2022)
[2] L. Padurariu et al., Acta Materialia, in press
[3] J. Lesseur et al., J. Eur. Ceram. Soc. 35, 337–345 (2015)