Electrochemical behavior of a Ti-based bulk metallic glass

In this study, potentiodynamic experiments were conducted with a Ti-based BMG alloy with a nominal composition of Ti43.3Zr21.7Ni7.5Be27.5 [atomic percent (at.%)], commonly known as LM-010. Electrochemical characterization was performed in a phosphate-buffered saline (PBS) electrolyte at 37 °C with a physiologically relevant dissolved oxygen content. This BMG exhibited passive behavior at the open-circuit potential with a low mean corrosion-penetration rate. A susceptibility to localized corrosion was observed but is not a concern at the open-circuit potentials. The resistance of the LM-010 alloy to localized corrosion was statistically equivalent to, or better than, all of the BMG materials and the 316L stainless steel for which direct statistical comparisons were possible. Microscopic examination revealed that the samples predominantly exhibited many scattered, small pits (diameter ⩽100 μm) in addition to several larger pits. Based upon the pit morphology and comparisons with the literature, it appears that localized corrosion initiated at clusters of inhomogeneities within the amorphous matrix.