The Carbothermal Reduction of Silica with Y2O3-MgO Powders

Abstract

The aim of this study is to examine the effect of MgO and Y2O3 to the carbothermal reduction and nitridation of silica. The synthetic silica, MgO and Y2O3 powders were premixed (4wt% MgO-6% Y2O3, 5% MgO-5% Y2O3 and 6% MgO-4% Y2O3) in the starting reactants depending on the final powder composition. Carbon black was added to the silica (SiO2) above the stoichiometric amount of oxygen (C/SiO2 ratio of 3). The carbothermal reduction and nitridation process was carried out in a tube furnace at 1400 degrees C, 1450 degrees C, and 1475 degrees C for 3 h under nitrogen gas atmosphere. The synthesized Si3N4 powder properties were examined by using X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectrosopy. In this study, MgO and Y2O3 powders dispersed in the final Si3N4 powder more homogeneously and thus formable and sinterable the starting mixing material is produced.