Transition Metal Dispersed Oxide Ceramic Nanocomposites with Multiple Functions

To develop new materials in which improved magnetic properties are consistent with excellent mechanical properties, transition metal nano-particles have been dispersed into alumina and zirconia ceramics. These nanocomposites (Al₂O₃/Co and ZrO₂/Ni which contains metals of less than 20 vol%), have been fabricated by the reduction and sintering of composite powders. These mixtures were prepared by wet chemical processes to obtain a desiable structure for ceramic/metal nanocomposites. In the sintered composites, nanometer-sized Co or Ni particles were mainly dispersed at the matrix grain boundaries of Al₂O₃ or tetragonal-ZrO₂, respectively. Fracture strength was improved because of microstructural refinement, and toughness was increased by incorporating large size and amount of metals. Ferromagnetic responses with enhanced coercive force were observed for these composites.