Calculation of Boundary Conditions between Internal and External Oxidation of Silicon or Chromium Containing Steels
| Periodical | Materials Science Forum (Volume 696) |
|---|---|
| Main Theme | High-Temperature Oxidation and Corrosion 2010 |
| Edited by | Toshio Maruyama, Masayuki Yoshiba, Kazuya Kurokawa, Yuuzou Kawahara and Nobuo Otsuka |
| Pages | 88-93 |
| DOI | 10.4028/www.scientific.net/MSF.696.88 |
| Citation | Shohei Nakakubo et al., 2011, Materials Science Forum, 696, 88 |
| Online since | September, 2011 |
| Authors | Shohei Nakakubo, Mikako Takeda, Takashi Onishi |
| Keywords | Chromite, Chromium Containing Steel, Fayalite, High Temperature Oxidation, Internal Oxidation, Oxygen Permeability, Rate Constant, Scale, Silicon Containing Steel, Transition from Internal to External Oxidation |
| Price | US$ 28,- |
The boundary constants between internal and external oxidation of Si or Cr containing steels (Fe-Si alloys or Fe-Cr alloys) at 850°C were calculated in order to clarify the formation mechanism of fayalite scale (Fe2SiO4) or chromite scale (FeCr2O4), which can form as a “sub-scale” in Si or Cr containing steels. The diffusion coefficient of oxygen in the alloy, Do, and the oxygen concentration at the specimen surface, NO(s), which are constituents of the internal oxidation rate constant, (2DONO(s)/NB(O)n), were calculated for various oxidation conditions, and the rate equation for internal oxidation was derived. By comparing the calculated and measured values of (2DONO(s)/NB(O)n), we confirmed that the rate equation determined for internal oxidation was reasonable. The boundary condition between internal and external oxidation of Si or Cr containing steels (Fe-Si alloys or Fe-Cr alloys) at 850°C were also calculated by substituting the calculated values of DO and NO(s) into the rate equation.
