Production of Cellular Ceramics by Gel Casting Ceramic Emulsions

Cellular ceramics have been produced by several methods, giving a wide range of macrostructures and properties. This work describes a novel route to produce cellular ceramics based on the gel casting of emulsions consisting in an aqueous ceramic suspension containing water-soluble organic monomers and an emulsified insoluble liquid phase. The effects of solids loading and kerosene fraction on the rheological properties of emulsions were characterized. Samples with different kerosene additions (20, 30, 40 and 50 %vol.) were produced and their green and sintered densities were measured. The results have shown a good correlation between the volumetric fraction of kerosene into the emulsion and the porosity of samples. Diametrical compression was used to evaluate the strength of sintered samples, which varied with the porosity between 18 and 37 MPa. The cellular structure was analyzed by SEM and revealed isolated pores for samples with low porosity, which changed to an interconnected network of pores as the porosity increased.