FEATURES OF SINTERING OF SILICA-DOPED TETRAGONAL ZIRCONIA NANOPOWDERS
The kinetics of the initial sintering stage of tetragonal zirconia nanopowders 3Y-TZP (ZrO2-3 mol% Y2O3) with the addition of SiO2 (concentrations of 0.2 and 2 wt %) is studied. The nanopowders are obtained in two ways: mechanical mixing and co-precipitation methods. The shrinkage of the compacts at the initial sintering stage is tested by non-isothermal sintering at the constant rate of heating. It is found that in the case of SiO2 doping by co-precipitation method, the predominant sintering mechanism is changed from the volume diffusion (VD) to the grain boundary diffusion (GBD). The SiO2 - doped nanopowders 3Y-TZP (0.2 and 2 wt% SiO2) produced by mechanical mixing are sintered under the predominance of the VD mechanism at the initial sintering stage.