Dissolved-Oxygen-Induced Intensive Pitting Corrosion of Amorphous ZrCu Alloys in Thin NaCl Solutions

Intensive pitting corrosion of amorphous (a-) Zr55Cu45 and a-Zr50Cu50 were observed by immersion in 0.2-200 mM NaCl solutions open to air at room temperature. The decreased corrosion rate in Ar-purged NaCl solution and no corrosion in ultrapure water open to air suggested that dissolved O-2 and Cl- played an important role on the corrosion of the ZrCu-base amorphous alloys. The open-circuit potential showed a negative shift with increasing the NaCl concentration from 0.2 to 200 mM like that of pure Cu. These observations suggest that the corrosion of the ZrCu-base amorphous alloys in the NaCl solutions was triggered by Cu dissolution which was induced by the reduction of dissolved O-2. The dissolution of Cu and Zr self-catalytically progressed by the local concentration of Cl- and hence the corrosion pits and holes were intensively formed even at the thinner NaCl concentrations. [doi:10.2320/matertrans.M2010437]