Electrochemical Behavior of Nanocrystalline Fe88Si12 Alloy in 3.5% NaCl Solution

Influence of microstructure on electrochemical behavior of nanocrystalline Fe88Si12 alloy has been investigated in 3.5 wt% NaCl solution. The results show that Fe88Si12 alloy with optimal corrosion resistance is composite of ordered Fe3Si and disordered Fe(Si) phases and grain size of 40 nm. Because the ordered Fe3Si structure is beneficial to form SiO2 film, which possesses good corrosion resistance compared with the Fe2O3 film from disordered Fe(Si). Moreover, although the decreased grain size is conducive to form preservative, as the grain size decreases to 10 nm, the grain boundary increases to above 30 vol%, which is the active sites for corrosion attack.