TEM analysis of grain boundary in Y2O3-Nd2O3-doped silicon nitride

Abstract

The grain boundary phase in gas-pressure sintered silicon nitride containing 1 mol% (SN1) and 10 mol% (SN10) of equimolar Y2O3-Nd2O3 was investigated using transmission electron microscopy. In SN1, grain boundary phases were observed in two-grain boundaries and multigrain boundaries. In SN10, pockets of an additive-rich glassy phase were observed beside two-grain boundaries and multigrain boundaries, showing that too much additive caused glassy pockets. SN1 contained a silica-rich phase in the multigrain boundary, although SN10 contained an additive-rich phase. A silica-rich phase with a lower melting temperature contributed to increased sinterability of SN1.