The Influence of Structure on the Corrosion of Glassy Copper-Zirconium Alloys

Abstract

Abstract Differences in structure between crystalline and glassy copper-zirconium alloys lead to subtle increases in the corrosion rate of crystalline compared to glassy material. Glassy alloys of Cu60Zr40 were melt spun and subsequently devitrified, yielding single phase polycrystalline material. Comparing the potentiodynamic polarization response of these structural types revealed no significant difference in ϕcorr. ba, bc, icorr. and io. Other alloys, Cu58Zr42 and Cu55Zr45, compared in glassy and crystal-line forms revealed that inhomogeneity, caused by precipitation of a second phase, did not alter the corrosion behavior from that of single phase Cu60Zr40. Corroded glassy surfaces were generally smooth except for scattered hemispherical features, while crystalline surfaces were densely populated with these features. Corrosion of copper-zirconium alloy occurs by the selective dissolution of zirconium in the vicinity of ϕcorr, whereas, at potentials noble to −0.1 VSCE, copper contributes to the anodic current. Above approximately 0.0 VSCE the alloys passivate. Results of potentiodynamic polarization studies suggest that for these alloys, unlike transition metal-metalloid glasses, devitrification does not significantly affect the corrosion kinetics of copper-zirconium alloys.