Effect of cooling rate on the location and chemistry of glassy phases in silica-doped 3Y-TZP ceramics

The morphology and the composition of glassy phases in silica-doped 3Y-TZP ceramics are studied for two extreme conditions of cooling. On the one hand, materials quenched after sintering exhibit silica-rich glassy phases both at grain boundaries and multiple junctions, with an enrichment of yttrium and zirconium. These observations are related to equilibrium at high temperature. On the other hand, materials slowly cooled exhibit glassy phases only at multiple junctions. During specific conditions of cooling, it is thus shown that dewetting can occur, giving rise to a low temperature equilibrium without glassy phase.