Corrosion Behaviour and Electrochemistry of Mg-5Y-2Nd- 0.5Zr-xSm (x=0, 1, 3 and 5) Alloys in 3.5 wt.% NaCl

摘要

The effects of Sm on the corrosion behaviours and electrochemistry of Mg-5Y-2Nd-0.5Zr magnesiumalloy were studied by the static weight loss method, electrochemical analysis, scanning electronmicroscopy and XRD. The results showed that the addition of Sm increased the open circuit potentialsof the tested alloys, decreased their self-corrosion current densities, and improved their corrosionresistances. As the Sm content increased, the corrosion rate of the alloy first decreased and thenreached a minimum at 3 wt.% Sm. At 3 wt.% Sm content, the corrosion rate of the alloy decreased to0.2121 mg.cm-2.h-1, which was 57% of that of the original alloy. At the same time, the Sm formed anew Mg41Sm5 phase in the alloy, which changed the quantities and distributions of the second phasesin the Mg-5Y-2Nd-3Sm-0.5Zr alloy. Adding a proper amount of Sm refines the precipitates and makesthe components and tissues uniform. The uniform, fine second phases could provide a good barrieragainst the generation and expansion of corrosion, thereby significantly improving the corrosionresistance of the alloy.