Sintering of magnesium partially stabilized zirconia – behaviour of an impurity silicate phase

Abstract

The formation and evolution of the grain boundary silicate phase in a commercially available 8 mol.-%Mg partially stabilized zirconia powder during the early stages of sintering has been studied using analytical transmission electron microscopy. The results show that forsterite is the first formed silicate phase in the range 1350–1450°C. Between 1550 and 1600°C, forsterite melts incongruently to a silica-rich composition which wets tetragonal zirconia, pulling the individual grains into clusters. However, below 1700°C, the silicate does not wet the cubic zirconia grain boundaries significantly. The consequences of this behaviour on the sintering of the ceramic are discussed.MST/559