Characteristics and corrosion studies of vanadate conversion coating formed on Mg-14 wt%Li-1 wt%Al-0.1 wt%Ce alloy

Mg-14Li-1Al-0.1Ce alloy is immersed in NH 4VO 3 + K 3(Fe(CN) 6) solutions with different NH 4VO 3 and/or K 3(Fe(CN) 6) concentrations, and different immersion time. The surface morphology and composition of the vanadate coating are then characterized by scanning electron microscopy with energy dispersion spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), and the corrosion behavior of the conversion coating is studied by polarization technique and electrochemical impedance spectroscopy (EIS). The experimental results indicate that the vanadate film with better corrosion resistance forms on Mg-Li-Al-Ce surface after the sample is immersed in 30 g L -1 NH 4VO 3 + 3.75 g L -1 K 3(Fe(CN) 6) solution at 80 °C for 10 min. The coating consists of V 2O 5, Li 2O and Mg(OH) 2. © 2012 Published by Elsevier B.V.