天然海水微生物对5083铝合金初期腐蚀行为的影响

Effect of biofilms on corrosion behavior of 5083 Al-alloy (5083AA) in natural seawater was investigated by means of epifluorescence microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy as well as measurements of open circuit potential, electrochemical impedance spectroscopy and pothentiodynamic polarization curves. Results showed that biofilms could form on the surface of 5083AA in natural seawater and acted as a protective layer for the substrate; moreover, in comparison with those in sterile seawater, the open circuit potential of the alloy was lower and the electron charge resistance (Rct) of the alloy was higher in natural seawater, which may be related with the reduction of cathodic reaction and microbiological corrosion inhibition on the alloy surface respectively. The microbiological corrosion inhibition may be due to the oxygen consumption by bacteria respiration and the existence of protective biofilms. On the other hand, the corrosion of 5083AA alloy could be inhibited in sterile medium to a certain extant, and this may be due to the formation of corrosion products on the alloy surface.