出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Ceramic foams have a wide range of applications (heat exchangers, liquid metal filters, porous electrodes, composite of rocket nozzles, etc.) due their properties, such as high melting temperature, high porosity, low thermal conductivity and low density. Since the mechanical resistance of this kind of material is linked to its cell walls features, this research analyzed the cell walls thickness of silicon carbide (SiC) ceramic foams by X-ray microtomography. This technique is a powerful non destructive way to analyze the internal structure of any object, generating images (cross sections) by attenuation of the X-ray beam. The analyses of these images allow us to determine the samples structural parameters through specific software. The samples have pore densities of 30, 60 and 100 pore per inch (ppi). A Skyscan-1172 microtomograph, operated at 50 kV high tension and 200 μA current was utilized for the measurements. The spatial resolution obtained was 24.8 μm and the measurement time was around 30 minutes for each sample. The analyses show that the cell walls of the 30 ppi sample have micropores. These micropores were observed at same images of 60 ppi cross sections too, but they were not observed at 100 ppi sample. It is probable that the cell walls of 100 ppi sample have micropores smaller than the achieved resolution.
