PROCESSING AND DENSIFICATION OF CERIA ZIRCONIA CERAMIC THROUGH EXTRUSION OF CERAMIC POLYMER MIXTURE

High-density 10 mol% ceria-zirconia ceramic has been fabricated by ext rusion of ceramic-polymer mixtures. The basic composite powder mixture has an average particle size of 3.5 mum and a tap density of 1976 kg/ m3. The torque rheological features of various ceramic-polymer (polyet hylene base) combinations were examined using a Brabender Plasticorder . The mixture containing 51 vol% (86.5 wt%) ceramic with a mixing torq ue value of 40 N m has been extruded to make 8-mm rods at 120-degrees- C. The initial extrusion torque of 240 N m slowly came down to 180 N m . The samples after debinding over a temperature ranging up to 600-deg rees-C were further sintered to high densities at around 1450-degrees- C, and were then found to have uniformly distributed grains with an av erage particle size of about 4 mum. The details of variation in rheolo gical properties of the ceramic-polymer mixtures with extrusion temper ature, packing of ceramic phase, debinding properties, densification c haracteristics and microstructural features are presented and are comp ared with the features of a uniaxially pressed sample.