Correlation between the corrosion behavior and corrosion ®lms formed on the surfaces of Mg82ÿxNi18Ndx (x ˆ 0, 5, 15) amorphous alloys

This study deals with the characterization of the corrosion ®lms formed on the surfaces of amorphous Mg82ÿxNi18Ndx (x ˆ 0, 5, 15) alloys in 3% NaCl solution saturated with Mg(OH)2. Hydrogen evolution test revealed that the addition of Nd has a bene®cial effect to reduce the dissolution rate of Mg82ÿxNi18Ndx alloys. SEM showed that the least severe corrosion occurred for the Mg67Ni18Nd15 alloy which has the highest Nd concentration. XPS revealed that the corrosion ®lm formed on Mg67Ni18Nd15 is the least hydroxidized among the amorphous Mg82ÿxNi18Ndx (x ˆ 0, 5, 15) alloys. The improved corrosion resistance of Mg67Ni18Nd15 is attributed to the high content of oxidized Nd in the corrosion ®lm preventing the detrimental Clÿ and CO3 2ÿ anions from penetrating. # 2001 Elsevier Science B.V. All rights reserved.