Inhibition Behavior and Mechanism of Molybdate Compound Inhibitor for Carbon Steel in Sea Water

The compound molybdates were tested as corrosion inhibitor and mechanism of corrosion of carbon steel in sea water was discussed by using weight loss,electrochemical polarization and XPS technique.The results indicated that the inhibition efficiency increased with increasing molybdate concentration,but single molybdate inhibitor had low inhibition efficiency.It had been found that there were synergistic effects between molybdate,sodium citrate,organic phosphate and Zn2+.The inhibition efficiency was over 93% in the proportion of 10mg/L molybdate,40mg/L sodium citrate,10mg/L HEDP,4mg/L Zn2+.The polarization curve and XPS showed that the compound inhibitors were anodic corrosion inhibitor which formed a compact film on carbon steel surface,the main composition of the film was iron oxide and complex,and Mo and P also formed precipitation film.