Fabrication of porous Al₂O₃ by microwave sintering and its properties

Porous composites of Al₂O₃/ZrO₂ with improved mechanical properties were fabricated by microwave sintering. The microstructure of the composite was characterized by the enhanced neck growth between the initially touching particles. This neck growth was ascribed to the selective heating of ZrO₂ between Al₂O₃ particles in the microwave heating, because of the high dielectric loss factor and good microwave-energy absorption ability of ZrO₂. The composite prepared by the microwave sintering exhibited higher elastic modulus and fracture strength than that prepared by conventional sintering. The improved mechanical properties of the microwave-sintered composites were attributable to the enhanced neck growth.