2\frac14Cr-1Mo鋼表面に発生した錆の高温ナトリウムによる還元
1984 年 48 巻 7 号 p. 699-704
詳細
1984 年 48 巻 7 号 p. 699-704
Specimens of 2\ frac14Cr-1Mo steel, previously rusted in the air, were immersed in stagnant sodium at temperatures from 423 to 673 K for 3.6×103 to 3.6×106 s. The reduction of rust in liquid sodium was investigated as a function of the immersion temperature and immersion time. The rust studied contained γ-FeOOH and Fe3O4.
In the temperature range of 423 to 573 K, wetting of rust with sodium required 3.6×105 s and this process was the rate-determining step for reduction in sodium. At temperatures above 573 K, wetting occurred within 3.6×103 s, followed by reaction with sodium. Rust was reduced in sodium by the processes in which γ-FeOOH was converted into Fe2O3 by dehydration, and Fe2O3 was changed into Fe3O4 and finally Fe. These were surface reactions, controlled by diffusion of oxygen through sodium. The activation energy of diffusion of oxygen was measured as 8.8 kJ/mol.
