Effect of Chlorella Vulgaris on Corrosion Behavior of Q235 Carbon Steel in Seawater

The effect of chlorella vulgaris in seawater on corrosion behavior of Q235 carbon steel was investigated by means of surface analysis techniques and electrochemical measurement method. The results show that the Q235 carbon steel uniformly corroded in culture medium without chlorella vulgaris, but localized corrosion occurred in culture medium with chlorella vulgaris. The open circuit potential showed a periodic oscillation with the change of immersion time in culture medium with chlorella vulgaris. The chlorella vulgaris and its metabolite could adhere to steel surface and form a biofilm which could effectively restrain metallic corrosion. Meanwhile, the oxygen produced by photosynthesis of chlorella vulgaris can cause cathodic oxygen depolarization reaction, which accelerated the corrosion of metal.