PHASE TRANSFORMATION IN SiO2-Si3N4 SYSTEM WITH Li2CO3 ADDITIVE

Abstract

In the present work, a series of samples were prepared by pressureless sintering from the starting materials of Si 3 N 4 (α and/or β phases), SiO 2 and Li 2 CO 3. The phase transformation was studied with emphasis on the influence of sintering temperature and Li 2 CO 3 content. Related phase transformation was observed and analyzed by SEM and XRD and probable mechanisms were given, which will be helpful for the further explanation to the oxidation mechanism of Si 3 N 4 based ceramics at elevated temperature.