Fe-Si系合金の陽極分極挙動について

Abstract

Fe-Si alloys having various Si contents of 0-14% were prepared by sinter siliconizing and subsequent diffusion treatment according to the procedure described in the author's previous report. Anodic polarization behaviors of the prepared specimens in 2N H2SO4 were investigated by the potentiostatic method.For the specimens having Si contents up to 6%, both of the maximum current density at the active state and the corresponding potential indicated each constant value, independent of Si content. At above 6% of Si content, however, the maximum current density decreased with the increase of Si content and the corresponding potential shifted to be less noble.Effects of Si content on the passive current density were quite different from those of abovementioned. That is, the passive current density increased with the increase of Si content up to 6%, but decreased with the increase of Si content above 6%.The anodic polarization was measured in 1 and 0.5N H2SO4 by using specimens having Si contents of 6 and 14%. The polarization for 6% Si specimen was only affected by concentration of H2SO4 and the potential range of the active state was extremely extended. In other words, 6% specimen was much less to be passive than other specimens when H2SO4 solution was diluted to 1 or 0.5N from 2N. It was confirmed by the author's another experiment that the above results mainly depended upon SO4-- concentration in H2SO4 solution.