Effect of NiO addition on microstructure, stability of tetragonal phase and the mechanical properties of yttria-stabilized tetragonal zirconia was investigated. (Y, Ni)-TZP solid solution was obtained by pressureless sintering. The fracture toughness was increased by solid solution of NiO. Neither reaction phase nor glassy phase was observed at the grain boundaries. From these result, it was determined that solid solution of NiO was destabilized tetragonal phase of Y-TZP. Y-TZP/Ni nanocomposite rhat contained nano-sized ni particles was also fabricated by internal reduction method. Some evaluations and discussions were carrued out for both (Y, Ni)-TZP solid solution and Y-TZP/Ni nanocomposite.

Keywords: Y-TZP, NiO, Ni, Internal reduction, Solid solution, Nanocomposite