The Preparation and Properties of Layered Ceramic-Matrix Composites with Ribbon-like Microstructures

The potential of repeated-deformation processing using paraffin oil for the production of layered ceramic-matrix composites with ribbon-like microstructures is demonstrated. The examples given here include the alumina/zirconia, aluminium titanate/alumina, aluminium titanate/mullite, calcium phosphate/zirconia and barium titanate/Ni systems. Viscous ceramic- and metal-powder pastes containing 57 to 60 vol.% of solids were prepared using paraffin oil as the dispersing medium. These pastes were rolled into tapes, which were then stacked together to form starting bi-material laminates in an A-B-A or A-B sequence, and plastically deformed by repeated folding and rolling at room temperature. After a sufficiently large, true plastic deformation, composites with ribbon-like microstructures were successfully produced. These composites exhibited an almost isotropic sintering behaviour and attractive mechanical, thermal and/or electric properties.