ELECTROCHEMICAL STUDIES ON THE CORROSIONINHIBITION OF PMTA FOR BRONZE IN AQUEOUS CHLORIDESOLUTION

摘要

PMTA(1-phenyl-5-mercapto-tetrazole) was considered as an effective corrosion inhibitor inrnarchaeological bronze conservation. Potentiodynamic polarization curve measurement was used to screenrnthe optimal forming conditions of PMTA protective film on bronze electrode, and to discuss thernelectrochemical mechanism of its corrosion inhibition in 0.5mol/L NaCl aqueous solution. The inhibitionrnbehavior of PMTA protective film was studied by means of electrochemical impedance spectrum (EIS).rnIts electrochemical parameters had been made a comparison with that of AMTrn(5-amino-2-mercapto-1,3,4-thiadiazole), MBI (2-mercapto-benzimidazole) and MBOrn(2-mercaptobenzoxazole). The test results showed that these inhibitors acted as a mixed inhibitor, thernorder of inhibition efficiency exhibited as AMT>PMTA>MBO >MBI at the same concentration ofrn100mg/L, and the retardation of anodic process by PMTA at 1000mg/L was much more effective. It wasrnalso found that the synergistic effect of PMTA and BTA could improve the inhibition efficiency obviouslyrnin immersion test. The film polarization resistance of PMTA protective film had increased torn27.421K ?·cm 2 from 401 ?·cm 2 of untreated bronze electrode in the medium. The results of AES and XPSrnmeasurements indicated that PMTA could react with bronze surface oxides to form composite complex torninhibit chloride corrosion.