Role of alloyed Y in improving the corrosion resistance of extruded Mg-Al-Ca-based alloy

We report that alloying with Y remarkably enhances the corrosion resistance of extruded Mg-Al-Ca based alloy. The corrosion rates, measured by immersion tests in 0.6 M NaCl solution at 25 degrees C, were 0.31 and 1.84 mm y(-1) for the Mg-6Al-1Zn-0.5Ca-0.3Mn (wt.%) alloys with and without 0.25 wt.% Y, respectively. The improved corrosion resistance is mainly attributed to a change in the type of Al-containing intermetallic particles toward reducing their electrochemical nobility, resulting in reduced H-2 evolution rate during corrosion. (C) 2017 Elsevier Ltd. All rights reserved.