New zinc–rare earth alloys: Influence of intermetallic compounds on the corrosion resistance
By Veys-Renaux, Delphine; Guessoum, Khadoudj; Rocca, Emmanuel; David, Nicolas & Belhamel, Kamel
Published in Corrosion Science
2013
Abstract
New ZnRE 1–2 wt.% alloys (RE = Ce, La and Mischmetal) were synthesized. Microstructural analyses reveal that rare-earth metals are exclusively present in intermetallic phases contained within the zinc matrix: CeZn11 or LaZn13 in binary alloys; Ce1-xLaxZn11 and CeyLa1-yZn13 in Zn–Mischmetal alloys. This phase equilibrium is confirmed by a thermodynamic description of the Zn-rich corner of Zn–Ce–La system. Both intermetallic phases CeZn11 and LaZn13 induce a cathodic inhibition of the corrosion of the Zn–RE alloys in comparison with pure zinc. In the specific case of cerium addition, a significant anodic inhibition is also observed.