Effect of grain boundaries on the formation of ozide scale in Fe-Cr alloy for SOFCs
The effect of grain boundaries on the formation of oxide scale was investigated for two different Fe-Cr alloys at 1073 K in H2-H2O atmosphere: typical stainless steel (SUS430) and Laves-phase forming Fe-Cr alloy. Identified oxide scale phases were Cr-Mn-(Fe) spinel and Cr2O3 on both surfaces of the Fe-Cr alloys. A relatively fast diffusion of elements was observed at the grain boundaries of SUS430 with a formation of ridges on the oxide scale surface. On the other hand, the diffusion of elements was controlled by precipitating a Laves-phase (Fe2(Nb, Mo) phase) at the alloy grain boundaries in the Laves-phase forming alloy. The oxide scale growth rates of the Laves-phase forming alloy was 9.8×0-15 cm2 s-1, which was much smaller than that of SUS430 (4.5×10-14 cm2 s-1) in the same condition. This was due to the lower diffusivity of elements at the grain boundaries of alloy. The control of elemental diffusivity at the alloy grain boundary (Laves-phase forming alloy) is effective to form stable and thin oxide scales on the Fe-Cr alloy surface in H2-H2O.
Ozide scale Fe-Cr alloy Interconnect Solid ozide fuel cells (SOFCs) Grain boundary
Teruhisa Horita Haruo Kishimoto Katsuhiko Yamaji Yueping Xiong Natsuko Sakai Manuel E.Brito Harumi Yokokawa
National Institute of Advanced Industrial Science and Technology (AIST), AIST Central 5, Higashi 1-1-1, Tsukuba 305-8565, Japan
国际会议
The 16th International Conference on Solid State Ionics(第十六届国际固态离子学会议)
上海
英文
1320-1324
2007-07-01（万方平台首次上网日期，不代表论文的发表时间）