INHIBITION BEHAVIOR OF MOLYBDATE INHIBITORS FOR CARBON STEEL IN SEA WATER

The compound molybdates as corrosion inhibitors of carbon steel in sea water were tested using weight loss,electrochemical polarization and surface analysis techniques.The inhibition efficiency increased with increasing molybdate concentration,but when the single molybdate concentration was lower than 30 mg/L the corrosion of carbon steel would be aggravated.There were synergistic effects between molybdate,organic phosphate (HEDP),Zn2+ and sodium gluconate.The inhibition efficiency was over 90% in the proportion of 40 mg/L molybdate,10 mg/L HEDP,4mg/L Zn2+ and 50 mg/L sodium gluconate.The compound molybdate inhibitor was an anodic corrosion inhibitor which formed a compact film on carbon steel surface,the main composition of the film was iron oxide with some Mo and P.