INHIBITION EFFICIENCY AND ADSORPTION BEHAVIOROF DODECYLAMINE ON N80 STEELIN CO2-SATURATED BRINE SOLUTION AT VARIOUS pHs

摘要

The inhibition efficiency and adsorption behavior of dodecylamine on the N80 steel inrnCO2-saturated brine solution at different pHs (4.9, 6.9 and 7.4) were investigated using potentiodynamicrnpolarization, FTIR-ATR and the contact angle measurement. The results showed that the inhibitionrnefficiency of dodecylamine depends on pH of the test electrolyte. The inhibition efficiency ofrndodecylamine increased with pH value from 4.9 to 7.4 and it acted as the anodic-type inhibitor whichrnmainly inhibited the anode reaction. At pH 4.9 the inhibition efficiency might be related to the adsorptionrnbehavior of dedecylamine on the naked metal surface which further affected the adsorption and desorptionrnof intermediate corrosion products on the metal surface, while at pH 6.9 and 7.4 it might be related to thernadsorption behavior of dodecylamine on the passive film and the synergetic performance betweenrndodecylamine and the passive film. Results of FTIR-ATR also showed that high pH environments werernmore favorable for the adsorption of dodecylamine. The results of the contact angle measurements furtherrnconfirmed that dodecylamine is more inclined to adsorb on N80 steel in higher pH electrolyte, and thernwater wettability of the surface of N80 steel in a higher pH electrolyte was lower than that in a lower pHrnelectrolyte.