Mechanical properties of Y-TPZ ceramics obtained by liquid phase sintering using bioglass as additive

Yttria stabilized tetragonal zirconia (Y-TZP) ceramics were sintered by liquid phase sintering at low temperatures using bioglass as sintering additive. ZrO2–bioglass ceramics were prepared by mixing a ZrO2 stabilized with 3 mol%Y2O3 and different amounts of bioglass based on 3CaO·P2O5–MgO–SiO2 system. Mixtures were compacted by uniaxial cold pressing and sintered in air, at 1200 and 1300 °C for 120 min. The influence of the bioglass content on the densification, tetragonal phase stability, bending strength, hardness and fracture toughness was investigated. The ceramics sintered at 1300 °C and prepared by addition of 3% of bioglass, exhibited the highest strength of 435 MPa, hardness of 1170 HV and fracture toughness of 6.3 MPa m1/2. These results are related to the low monoclinic phase content, high relative density and the presence of the thermal residual stress generated between the ZrO2-matrix and bioglass grain boundary, contributing to the activation of the toughening mechanisms.