Evaluating corrosion resistances of Fe-based amorphous alloys by YCr/Mo values

In this paper, the synthetic effect of Cr, Mo and Y on corrosion resistance was explored, and the frim value was employed to evaluate the corrosion resistance. The composition of amorphous alloy was designed by mixing the Fe41Co7Cr15Mo14C15B6Y2 (BMG1) with good glass forming ability (GFA) and Fe50Cr22B23Ni5.4 with a high corrosion resistance at 9:1 ratio. At the same time, the contents of Y, Mo and Cr were fine-tuned. The electrochemical tests demonstrated that the passivation current density decreased with the increase of the Yam value. The passivation current density of Fe-based amorphous alloy was reduced by about half an order of magnitude. The fitting result showed that the logarithm of passivation current density (I) and the Yam value (X) were logarithmic relationship, and the fitting equation was J=-5.649+4.904x 10(15)e(-17) (52x). The X-ray photoelectron spectroscopy (XPS) results showed that the Yam value played a key role in stability of passive films. When the Yam value was low, the Cr6+ ion, Mo6+ ion were enriched in the initial stage of passivation process, then leading to the increase. passivation current density. However, when the Yam value was high, the low-valence Fe2+, Cr3+, and Mo4+ ion were enriched more easily, which result in small passivation current densities and more stable passive films.