Synthesis, mechanical properties and bioactivity of nanostructured zirconia

• A new technique has been proposed to prepare 10–30 nm 3Y – TZP nanopowders.
• Cuboid zirconia blanks are fabricated through centrifuge casting.
• Average grain size varies from 100 to 400 nm after sintering at 1350 °C for 2 h.
• Hardness and fracture toughness are found as 13.5 GPa and 3.5 MPa.m1/2, respectively.
• Nanoscale hydroxyapatite deposits on stress-induced nucleation site of ZrO2 after optimum time.

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 2 h. Cuboid(50 × 25 × 20 mm3) zirconia blanks are fabricated through centrifuge casting and followed by sintering at 1350 °C for 2 h. 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.m1/2, 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.