Synthesis, mechanical properties and bioactivity of nanostructured zirconia

Yttria stabilized zirconia 3Y - TZP nanopowders (10-30 nm) are prepared through direct precursor calcination of mixed zirconium oxychloride and yttrium nitrate solutions at 600°C for 2h. Cuboid(50×25×20 mm(3)) zirconia blanks are fabricated through centrifuge casting and followed by sintering at 1350°C for 2h. Sintered zirconia blanks exhibit 24% volume shrinkage and 98% relative density with average grain size of 250 nm. Vickers hardness and indented fracture toughness of sintered blanks are measured as 13.5 GPa and 3.5 MPa.m(1/2), respectively. Bioactivity of nanostructured zirconia originates after four weeks incubation in simulated body fluid solution. An optimum time is required for the deposition of hydroxyapatite nanoparticles on stress-induced nucleation site of nanostructured zirconia.