μCT Analysis of Porous Cermet Membranes with the Use of Enhanced Filtration and Binarization Algorithms

This paper presents the results of tomography studies of a porous ceramic–metal membrane based on coarse-grained aluminum oxide. For the development of a technology for the manufacturing of ceramic–metal membranes with specified properties by the method of self-propagating high-temperature synthesis, it is important to have information about the internal morphological structure of the membrane, which determines such characteristics as the porosity, specific surface area, etc. A closer look at the data of X-ray computed microtomography (µCT) would allow one to study the effect of the technological-process parameters on the morphology of the membrane and, consequently, on its properties. Tomographic measurements of the membrane are carried out using an original laboratory setup. It is shown for the first time that single-pixel pores and “levitating stones” have an effect on the calculated characteristics of the membranes. We use this fact in our data-processing strategy. The morphological characteristics are calculated from the results of tomographic reconstruction after the filtration of noise and binarization by Otsu’s method. Comparison of the values of the morphological characteristic calculated from the binarized reconstructed image with the results of measurements by other methods shows good agreement in the magnitudes of the porosity and pore size and a difference in the values of the specific surface area, which can be explained by a discrepancy in the spatial resolution of the employed methods.