Abstract
The oxidation behavior of porous reaction-bonded silicon nitride has been investigated in the temperature range 900-1400℃ for up to 3 hours by the Simultaneous Thermal Analysis technique. The mechanism of oxidation is complex and depends critically on the temperature. At low temperatures in excess oxygen, a protective silica film is formed by passive oxidation. The low P_<o2> in pores beneath the film leads to active oxidation of both the silicon nitride and silicon oxynitride which may be formed during fabrication process. A model for the roles of the silica film and the silicon oxynitride was proposed and discussed.
