Development of multylayer porous media using colloidal processing

This work describes the development of copper oxide multilayer porous media with 30 vol.% of charcoal, used as space holder material, which was milled during different time periods for 5−45 min. A previews work dealing with different space holder concentrations showed that 30 vol.% presents the best properties of mechanical resistance and porosity for the desired application and that each concentration presents a different percentage of retraction. In the present work, to be able to develop multilayer porous media, the concentration was maintained constant and the charcoal particle size was modified. The rheological behavior of the mixture was studied through constant rate curves. The ceramic bodies were produced in different layer combinations through aqueous colloidal processing, using slip casting as a molding technique. The final bodies of each layer were heat treated and characterized to obtain their porosity, pore size distribution, permeability, and effective thermal conductivity. The sintered samples had porosity of 60.2 ± 2.0%, bimodal pore size distribution, permeability of 10−14−10−13 1/m2 (depending of the space holder average particle size), and effective thermal conductivity of 5.6 W/(m·K). The multilayer porous media interface was characterized through scanning electron microscope images.