Tape-cast alumina-zirconia laminates: Processing and mechanical properties

(A)lumina-zirconia laminar ceramics made from layers of different compositions with different stacking sequences were fabricated by tape casting and compared. A phosphate ester dispersant was optimized in MEK/EtOH and an optimum formulation of organic components for tape casting was defined. The fracture resistance, toughness and elastic properties were characterized. A significant improvement of both the fracture resistance and the toughness, from 380 to 560 MPa and from 3.7 to 8 MPa root m respectively, was gained between the pressed alumina monolith and the tape-cast Al2O3-ZrO2 composites. The improvement was tentatively related to the presence of residual stresses at both the microscopic (phase transformation toughening) and at the macroscopic scale (interface effects). (C) 1996 Elsevier Science Limited.