Effect of chlorella vulgaris on corrosion behavior of Mg-3Y-1.5Nd alloy in natural seawater

Abstract

The effect of chlorella vulgaris on corrosion behavior of Mg-3Y-1.5Nd alloy in f/2 culture medium was studied by means of X-ray diffraction, scanning electron microscope, energy dispersive analysis system of X-ray and other electrochemistry test. Results show that the main corrosion products on the surface of alloy with and without chlorella vulgaris are Mg (OH)2,Mg3 (PO4)2 and Mg2 (OH)3Cl; Mg and O are present on the specimen surface, and the content of Mg in culture medium with chlorella vulgaris (29.6%) is lower than that without chlorella vulgaris (39.8%); and corrosive ions invade the loose corrosion product structure and promote further corrosion of the alloy; the high O2 concentration produced by the photosynthesis of chlorella vulgaris results in the increase of local O2 concentration underneath the biofilm, which adds oxygen reduction cathodic currents and enhances corrosion. It is conduded that the average corrosion rate in the presence of chlorella vulgaris is more serious than that in the absence of chlorella vulgaris.

Keywords

• mg-3y-1.5nd alloy
• chlorella vulgaris
• microbiological corrosion
• electrochemistry