Porous ceramics have great technological importance, since they combine ceramics unique properties, such as refractoriness and chemical resistance, with high surface area, high permeability and low thermal conductivity. Nevertheless, increasing porosity generally deteriorates the mechanical behavior of ceramics. In this work, the mechanical properties of ceramic foams produced by the aeration of ceramic suspensions associated to the polymerization of previously added monomers (gelcasting process) is investigated. The macrostructure that results from this process is constituted of nearly spherical pores, a geometry that minimizes the concentration of mechanical stresses. Moreover the cell walls can be well densified during sintering, resulting in a homogeneous microstructure. The mechanical strength of ceramic foams with several densities was evaluated under 4-point bending test and compression. The results of flexural strength were used to calculate the Weilbull modulus of the samples. The Young's modulus and shear modulus were measured using a mechanical resonance method. The results allowed a better comprehension of the main factors that affect the mechanical properties of this new material category and provided insights for its improvement.
gelcasting; ceramic foam; modulus of rupture; elastic moduli; Weilbull modulus
