Sandwich materials formed by thick alumina tapes and thin-layered alumina-aluminium titanate structures shaped by EPD

The objective of this work was to analyse the potential of the alumina (Al2O3)-titania (TiO2) system to fabricate laminates with very thin deflecting layers. Alumina-aluminium titanate structures formed by thick self-supported alumina tapes (400 mu m) joined together by layered alumina-aluminium titanate structures shaped by EPD have been developed and their mechanical response has been evaluated as a function of the thickness of the layered structures. For this purpose the stability of alumina and alumina-titania suspensions in ethanol was optimized and the EPD parameters to control the growth of layers on non-conductive substrates were analysed. Two different sandwich structures formed by external alumina tapes joined by multilayer systems built by EPD were fabricated. Differences between the multilayer systems were based on the thickness of the layers. Large portions of the central parts of the laminates with thicker layers remained un-fractured while multiple delaminations were observed in the central parts of the specimens with thinner layers that presented wood-like fracture. The fracture modes were reflected in the load-displacement curves as higher loads were needed to fracture the more resistant thicker ligaments whereas larger displacements were admitted by the specimens with thinner layers due to multiple delaminations. (C) 2008 Elsevier Ltd. All rights reserved.