Sodium-assisted oxidation of reaction-bonded silicon nitride
- Cite this article as:
- Mayer, M.I. & Riley, F.L. J Mater Sci (1978) 13: 1319. doi:10.1007/BF00544739
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The oxidation of reaction-bonded silicon nitride in air, and with small amounts of sodium carbonate applied to the sample surface, has been studied. The action of the alkali is to cause short-term enhanced oxidation,which is terminated when specific compositions of the product sodium silicate glass are attained. These correspond closely to liquidus compositions in the Na2O-SiO2 system, and it is postulated that the retardation in the oxidation rate at this stage is due to the formation of a stable tridymite film at the silicon nitride-glass interface. The implications for the high temperature stability of reactionbonded silicon nitride components in alkali contaminated atmospheres are discussed.