Formation of silicon oxinitride from Si 3N 4 and SiO 2 in the presence of Al 2O 3

Abstract

The formation of Si 2N 2O from SiO 2 and α-Si 3N 4 powder mixtures with addition of 3 mol % Al 2O 3 was investigated. An eutectic at 98 mole % SiO 2 and 2 mole % Si 3N 4 was formed at 1863 K which is decreased by the Al 2O 3, thus enabling the formation of Si 2N 2O via the liquid phase. Microstructural analysis by TEM showed a strong orientation between Si 2N 2O and α-Si 2N 4 crystals. Oxidation resistance and bending strength were also measured.