Three-Dimensional Investigation of the Pore Space in Carbon Preforms of Metal Infiltrated Carbon Based Silicon Carbide Ceramics

Abstract

The microstructures of MiCaSiC ® ceramics (Metal Infiltrated Carbon based Silicon Carbide) depend among others on the pore space properties of the carbon preforms before the liquid silicon infiltration (LSI). The aim of this work was to obtain three-dimensional information of the complex and non-homogeneous pore network in the carbon preform using microfocus X-ray computed tomography (μCT) and adequate image processing algorithms. It was found that it is possible to identify the optimum silicon infiltration direction by analyzing the porosity profiles. The pore size distribution was derived from the tomographic images using granulometry and cells reconstruction methods. Both results were compared with the distribution provided experimentally by the mercury intrusion porosimetry (MIP). Some relevant structural parameters (e.g. geometrical tortuosity, surface density, etc.) were calculated from the tomograms. A representative unit cell (RUC) was derived on the basis of those values. This information will reduce the computational efforts when performing μCT data based simulations, in order to better understand the LSI process for MiCaSiC®.