Alumina/kaolin laminated composites have been fabricated at 1650°C by firing multilayers of 1mm thick alumina sheets and 50 or 100μm thick kaolin tapes. During firing, the kaolin layers changed to mixed phases of mullite and SiO2-rich glass. The bending strength of these composites dose not depend on the numbers of laminated kaolin tapes, but depends on the thickness. It was camparable with that of monolithic alumina sheets. The fracture behavior of laminated composites varied with the thickness of kaolin tapes. The composites with pillar-like mullite crystals grown perpendicular to the kaolin layers of 50μm showed a linear relation in the load/deflection curve. On the other hand, the composites prepared with 100μm-kaolin tapes contained two types of mullite crystals: pillar-like mullite crystals grown at the interface between alumina sheet and kaolin tape and needle-like mullite crystals formed in the center area of the kaolin tape. These composites with thicker kaolin tapes showed a non-linear relation in the load/deflection curve.
