Abstract
The distribution and the morphology of glass phase in polycrystals are affected by the dihedral angle and the volume fraction of the glass phase. The effects of temperature and chemical composition of intergranular glass on dihedral angle of glass-doped 3-mol%-yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) were studied by transmission electron microscopy (TEM). The intergranular glass was either SiO2 (melting point of 1700°C) or Y2O3-Al2O3-SiO2 eutectic glass (YAS glass: melting point of 1350°C). The average dihedral angles of SiO2-doped and YAS-doped 3Y-TZP, which were sintered at 1300°C, were found to be 70° and 50°, respectively. The dihedral angle in YAS-doped 3Y-TZP decreased to 25° after annealing at 1500°C, whereas that in SiO2-doped 3Y-TZP remained constant. From the relationship between the dihedral angle and the ratio of grain boundary energy to solid/glass interface energy (γSS/γSL), it was suggested that γSS/γSL increased at elevated temperatures higher than the melting point of glass.
