The reaction behavior of α-Si3N4 powder at 1100–1500 °C for 10 h under different oxidizing conditions was investigated using thermogravimetric analysis. The phase constitution and microstructure were characterized using X-ray diffraction, optical microscope, scanning electron microscopy, transmission electron microscope and fourier transformation infrared spectroscopy. The results showed that the reaction behavior of α-Si3N4 powder varies depending on temperature and the oxidizing atmosphere. At 1100–1200 °C, water vapor enhanced the reaction due to its specifically inward oxidation. Above 1300 °C, H2O further reacted with SiO2 to form silicon tetrahydroxide, which caused the reaction behavior to follow the paralinear rate law.
α-Si3N4 powder Different oxidizing conditions Kinetics
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The authors express their appreciation to the National Science-technology Support Plan Projects (Grant 2013BAF09B01), National Nature Science Foundation of China (51104012), New Century Excellent Talents in University (NECT-12-0779) and the Fundamental Research Funds for the Central Universities (FRF-TP-14-113A2) for financial support.