Morphological Models of Networks of Inter-granules Micropores: Identification and Validation Based on 2D and 3D Imaging

In view of predicting the overall thermal conductivity of ceramics with a granular microstructure exhibiting complex networks of pores preferably located at the interfaces between granules, a simple microstructural model has been developed to capture the dominant features of such a specific morphology. Generated 3D virtual networks of pores are obtained as the intersection of a Voronoi tessellation, representing the granules, and a boolean model of monodisperse overlapping spheres [1]. The two non-dimensional parameters fully determining such networks have been first adjusted so as to reproduce at best some morphological properties extracted from 2D optical images of various real samples [2]. To further validate this model, several small samples of the same materials have in addition been imaged in 3D by synchrotron X-ray micro-computed tomography, with a specific setup adapted to the very strong attenuation of these ceramics. The consistency of the results measured in 2D on cross-sections of tomography images with those measured on optical microscopy images has been first checked. Next, qualitative comparisons between observed 3D pore networks and simulated ones with parameters adjusted from 2D observations have been complemented by more quantitative ones.