Broad porosity range can be obtained in ceramic foams employing the gelcasting technique coupled to the aeration of ceramic suspensions. Alumina based foams were produced with porosity in the range of 62 to 87 volume-%, which corresponded to relative densities between 0.13 and 0.38. Fitting models after Mackenzie, Boccaccini and Gibson and Ashby, describing the dependency of elastic moduli on density or porosity, were applied. The bar resonance technique was used to determine the values of Young's modulus, shear modulus and Poisson's ratio of these cellular material. The fitting model that best describe the dependence of elastic moduli on porosity could be identified and discussed.
ceramic foams; gelcasting; elastic modulus; bar resonance; alumina
