Resistance of Si_2N_2O ceramics to oxidation and erosion of molten silica

Si 2N 2O ceramics was fabricated from powder by hot pressing in N 2 atmosphere. The resistance of the ceramic sample to oxidation and erosion of molten silica was investigated. The bulk density and open porosity of the ceramic sample were measured according to the Archimedes principle in water. Then fracture surface of the sintered body was observed by SEM. The results and analysis indicate that the resistance of Si 2N 2O ceramics to oxidation and erosion of molten silica increases when its density increases and/or its open porosity decreases. Moreover, they also reveal that the oxidation process is an unsteady dispersing process with oxygen as the constant source, and the resistance to erosion of molten silica related to the quantity of grain boundary in unit surface area. The lowest mass gain is 2.4 g/m 2 after oxidizing at 1 000 ℃ for 100 h in air, while the lowest mass loss is 2.9 g/m 2 after 40 h erosion in molten silica.