Journal of Materials Science, Vol.34, No.11, 2641-2649, 1999
Processing and thermomechanical evaluation of fibre-reinforced alumina filters
Impregnation of polymeric foams with ceramic suspensions has been widely employed in industry to fabricate ceramic filters of various shapes and controlled pore size at a reduced processing cost. Ceramic filters find application in cast metal industry to remove the undesired impurities from the melt, leading to products of higher quality. This paper reports a complete study on the fabrication of fibre-reinforced alumina filters. Rheological measurements of ceramic suspensions showed that the slip adherence on polymer substrate was largely improved when thickening agent was incorporated into the compositions, as a result of the increase in pseudoplasticity and in viscosity. Thermomechanical evaluation of the filters produced with fibre addition revealed that the fibre reinforcement improved the mechanical performance and reduced the damage by applied thermal stresses. Strengthening and toughening of the ceramic matrix has been explained based on the fibre properties, fibre-matrix interface strength and thermal expansion mismatch that may occur in mixed systems.