Technical Note: The Corrosion Behavior of a Ni Based Amorphous Alloy—The Effect of Devitrification Available to Purchase

Many glassy alloys prepared by rapid solidification from the liquid phase have demonstrated significantly better corrosion resistance than their conventionally prepared counterparts.^1-7  Researchers attribute this phenomenon to the following three factors: (1) structure (grain boundaries, dislocations, etc.), (2) chemical composition, and (3) homogeneity (composition fluctuation, precipitates, etc.). However, because of the complex nature of corrosion resistance, a single dominant factor which contributes to the superior corrosion resistance of amorphous alloys has not yet been elucidated. A report by Naka, et al.,⁸  on Fe-Cr-P-C and Fe-Ni-Cr-P-B alloys in 1N HCl showed that the passive current density increases two orders of magnitude because of the formation of the SS (solid solution) phase from the amorphous matrix. However, a recent study by Turn and Latanision⁹  of Cu-Zr alloys showed no significant influence of structure and homogeneity (second phase precipitation) on general corrosion behavior. These results strongly suggest that the different...