Effects of Yttrium and Strontium Addition on Electrochemical Behavior of Mg-14Li-1Al Alloys

Abstract:

Mg-14Li-1Al (LA141), LA141-0.3Y, LA141-0.3Sr and LA141-0.3Y-0.3Sr alloys were prepared and their electrochemical behavior in 0.7 mol/L NaCl solutions was investigated by means of potentiodynamic polarization, potentiostatic current-time and electrochemical impedance spectroscopy measurements as well as by scanning electron microscope examination. The effects of gallium oxide as an electrolyte additive on the potentiostatic discharge performances of these magnesium alloys were studied. The discharge activities and utilization efficiencies of these alloys increase in the order: LA141LA141-0.3Sr>LA141-0.3Y>LA141-0.3Y-0.3Sr. Scanning electron microscopy indicates that the alloy elements Y and Sr can prevent the formation of dense oxide film on the alloy surface and accelerate the peeling off the oxide products. In the respect of improving the electrochemical performance Y is more obvious than Sr and it is the most significant when Y and Sr are alloyed in magnesium at the same time. LA141-0.3Y-0.3Sr exhibits the best performance in terms of activity and utilization efficiency and the most loose oxide products on alloy surface.