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Corrosion Behavior of an Al-Fe-Gd Metallic Glass in Aqueous Environments

Buchheit Jr., R.G.; Stoner, G.E.; Shiflet, G.J.

The corrosion behavior of a rapidly solidified Al-Fe-Gd alloy glass was studied in aqueous chloride environments of varying pH using potentiodynamic polarization. The corrosion behavior of a rapidly solidified pure Al glass, crystalline Al-Fe-Gd alloy and crystalline Al were measured for comparison. Due to lattice disorder, the dissolution rate of the glasses in the passive region was greater than that of their crystalline counterparts. The breakaway potentials measured for the glasses were more positive than those of the crystalline metals because film breakdown initiation sites like second phase particles and internal boundaries were not present in the glass. Alloy glass specimens exposed to alkaline solutions exhibited lower passive current densities and higher breakaway potentials than expected. This appeared to be a result of an enrichment of oxidized Fe at the specimen surface. This Fe-rich protective film also appeared to form in pits which developed on crystallized specimens tested in neutral chloride solutions.