Characterisation of mechanical and fracture behaviour of Al2O3/ZrO2/BaTiO3 laminate by indentation

The paper describes the preparation of laminate piezo-ceramic composite consisting of Al2O3, ZrO2 and BaTiO3 layers and proves the idea of residual stresses utilization for crack deflection and handling with the brittleness of BaTiO3. The laminate was prepared by alternate electrophoretic deposition. Although the laminate was sintered at 1300 degrees C and consisted of layers having a density between 57 % (ZrO2) and 73 % (BaTiO3), the hardness and elastic modulus of layers corresponded to those of free sintered monolithic ceramics at a comparable level of porosity. The crack deflection at the interface between individual layers was observed having the same effect and magnitude as deflection observed in the case of fully dense Al2O3/ZrO2 laminates. An interlayer developed on the interface between Al2O3 and BaTiO3 had no negative impact on crack propagation.