ELECTROCHEMICAL STUDY ON THE CORROSION BEHAVIOR OF X70 STEEL IN ACID SOLUTIONS WITH H₂S

The influences of the acidity of solution,temperature,immersion time and polarization potentials on corrosion behavior of X70 steel in weak acidic solutions with H2S were studied by means of potentiodynamic polarization curves and electrochemical impendence spectroscopy.With the increasing of the acidity of the solution promoted the cathodic process,thus accelerated the corrosion rate of X70 steel.With the increasing of temperature ,the corrosion current increased gradually,the corrosion potential became negative firstly and then positive.With the extension of immersion time,FeS film became more steady and inhibition was strengthened.The FeS protective film could suppress the electrode reaction with the increasing of electrode potential in a certain region,however,when the electrode potential rised to more pasitive values,this kind of protective film would be destroyed and lost protective function.