Modified Wagner model for the active-to-passive transition in the oxidation of Si3N4

Junjie Wang, Litong Zhang, Qingfeng Zeng, Laifei Cheng, Yongdong Xu

科研成果: 期刊稿件文章同行评审

2 引用 (Scopus)

摘要

Si3N4 is used as the coating material of space shuttle structures which receive very high thermal fluxes during the atmospheric re-entry phase. Two main regimes govern the oxidation of Si3N 4: the passive oxidation, with the formation of a protective silica layer leading generally to a mass gain, and the active oxidation, with vaporization of SiO leading to a mass loss of the sample. To ensure that silicon nitride will efficiently protect a material in given oxidizing environments, its own oxidation behaviour must be previously known. Therefore, the active-to-passive transition of Si3N4 oxidation is a problem of deep scientific importance and of wide technological relevance. In this paper, a modified Wager model for the active-to-passive transition in the oxidation of Si3N4 is presented, which includes the non-equilibrium effects caused by the mass transfer. The present theoretical calculations satisfactorily explained the reported experimental and theoretical data. The influence of flow rate on the active-to-passive transition boundary has been explained using our model. The rate controlling mechanism of the oxidation at the active-to-passive transition point is proposed.

源语言英语
文章编号115412
期刊Journal of Physics D: Applied Physics
41
11
DOI
出版状态已出版 - 7 6月 2008

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