The Effect of Grain Boundaries on the Surface Rearrangement during Wustite Reduction within its Range of Existence

概要

論文の詳細を見る
Dense polycrystalline wüstite samples equilibrated with 50%CO-CO2 gas mixture for 432 ks has been reduced at 1073 K using 60%CO-CO2 gas mixture to study the effect of grain boundaries on the surface rearrangement process. Orientations of surface grains on the wüstite specimens are measured by applying electron backscattering pattern technique. The development of the surface arrangement away from grain boundaries is significantly larger than that near grain boundaries. Quick establishment of the equilibrium with the reacting gas in the region near grain boundaries at the early stage of the reduction makes it difficult to continue the transportation of Fe2+ ions into deep interiors of wüstite by the volume diffusion process. As a result, the surface rearrangement is retarded at the surface near grain boundaries after the equilibration of the surface. The transportation of Fe2+ ions at the surface layer away from grain boundaries by volume diffusion is small but not negligible so that the surface rearrangement away from the grain boundary is possible to continue until almost the whole sample is equilibrated.
社団法人日本鉄鋼協会の論文
2005-05-15