Effect of Fe and partial pressure of oxygen on the formation and phase transformation behavior of Al2O3 scale |
| |
| Authors: | S Hayashi Y Takada I Saeki A Yamauchi Y Nishiyama T Doi S Kyo M Sato |
| |
| Affiliation: | 1. Division of Materials Science and Engineering, Faculty of Engineering, Hokkaido University, N‐13 W‐8, Sapporo, Hokkaido 060‐8628 (Japan);2. Department of Materials Science and Engineering, Muroran Institute of Technology, 27‐1, Mizumoto‐cho, Muroran, Hokkaido 050‐8585 (Japan);3. Corporate Research & Development Laboratories, Sumitomo Metal Industries, LTD. 1‐8 Fuso‐cho, Amagasaki, Hyogo 660‐0891 (Japan);4. Power Engineering R&D Center, Kansai Electric Power CO., INC, 3‐11‐20, Nakoji, Amagasaki, Hyogo 661‐0974 (Japan);5. Japan Synchrotron Radiation Research Institute, 1‐1‐1 Koto, Sayo‐cho, Hyogo 679‐5198 (Japan) |
| |
| Abstract: | The effect of oxygen partial pressure on the phase transformation of Al2O3 scale on various Fe–Al alloys with and without very thin (～100 nm) Fe coating was investigated. Fe‐coating on Fe–Al alloys can effectively suppress metastable Al2O3 formation, but little effect was observed when the samples were oxidized in a low partial pressure of oxygen. Under the low ${\rm P}_{{\rm O}_{{\rm 2}} } $ atmosphere, metastable to stable α‐Al2O3 scale phase transformation on both Fe‐coated and non‐coated Fe–Al alloys was significantly delayed. The lattice spacing of α‐Al2O3 scale formed in air decreased with increasing alloy Al content. Further decrease in the lattice spacing of α‐Al2O3 scale was observed when the alloy was oxidized in low ${\rm P}_{{\rm O}_{{\rm 2}} } $ . The results obtained clearly indicated that the formation of Fe2O3 or Fe3+ in metastable Al2O3 accelerated the metastable to stable α‐Al2O3 scale transformation. |
| |
| Keywords: | |
|
|
